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Ahmad-Kamil, E. I., R. Ramli, S. A. Jaaman, J. Bali i J. R. Al-Obaidi. "The Effects of Water Parameters on Monthly Seagrass Percentage Cover in Lawas, East Malaysia". Scientific World Journal 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/892746.
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Seagrass is a valuable marine ecosystem engineer. However, seagrass population is declining worldwide. The lack of seagrass research in Malaysia raises questions about the status of seagrasses in the country. The seagrasses in Lawas, which is part of the coral-mangrove-seagrass complex, have never been studied in detail. In this study, we examine whether monthly changes of seagrass population in Lawas occurred. Data on estimates of seagrass percentage cover and water physicochemical parameters (pH, turbidity, salinity, temperature, and dissolved oxygen) were measured at 84 sampling stations established within the study area from June 2009 to May 2010. Meteorological data such as total rainfall, air temperature, and Southern Oscillation Index were also investigated. Our results showed that (i) the monthly changes of seagrass percentage cover are significant, (ii) the changes correlated significantly with turbidity measurements, and (iii) weather changes affected the seagrass populations. Our study indicates seagrass percentage increased during the El-Nino period. These results suggest that natural disturbances such as weather changes affect seagrass populations. Evaluation of land usage and measurements of other water physicochemical parameters (such as heavy metal, pesticides, and nutrients) should be considered to assess the health of seagrass ecosystem at the study area.
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Zabarte-Maeztu, Iñigo, Fleur E. Matheson, Merilyn Manley-Harris, Robert J. Davies-Colley, Megan Oliver i Ian Hawes. "Effects of Fine Sediment on Seagrass Meadows: A Case Study of Zostera muelleri in Pāuatahanui Inlet, New Zealand". Journal of Marine Science and Engineering 8, nr 9 (21.08.2020): 645. http://dx.doi.org/10.3390/jmse8090645.
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Seagrass meadows are vulnerable to fine sediment (mud) pollution, with impacts usually attributed to reduction in submerged light. Here we tested two non-exclusive hypotheses, that mud particles (<63 µm) impact seagrasses through both (1) the light climate and (2) changes in substrate physico-chemistry. We tested these hypotheses in Pāuatahanui Inlet, New Zealand, by comparing seagrass presence, abundance, and health, together with light climate and substrate physico-chemistry at contrasting habitats where (1) seagrass used to thrive but no longer grows (historical seagrass), (2) seagrass still persists (existing seagrass) and (3) seagrass has been present recently, but not currently (potential seagrass). Historical seagrass substrate had significantly higher mud (35% average), bulk density (1.5 g cm−3), porewater ammonium concentration (65 µM), and a more reduced redox profile (negative redox at only 2 cm soil depth) as well as a lower light availability when submerged compared to other habitats, while total daily light exposure differed little between habitats. This suggests that failure of seagrass to recolonize historical seagrass habitat reflects substrate muddiness and consequent unfavorable rhizosphere conditions. Our results provide evidence for the multi-stressor effects of fine sediment on seagrasses, with substrate suitability for seagrass being detrimentally affected even where light exposure seems sufficient.
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Batuwael, Anggi Wawan, i Dominggus Rumahlatu. "ASOSIASI GASTROPODA DENGAN TUMBUHAN LAMUN DI PERAIRAN PANTAI NEGERI TIOUW KECAMATAN SAPARUA KABUPATEN MALUKU TENGAH". Biopendix: Jurnal Biologi, Pendidikan dan Terapan 4, nr 2 (22.05.2019): 109–16. http://dx.doi.org/10.30598/biopendixvol4issue2page109-116.
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Background: Seagrasses are flowering plants (Angiosperms) that are able to adapt fully in waters with high salinity or live immersed in water. Seagrass has true rhizomes, leaves and roots like plants on land. Seagrasses usually form fields called seagrass beds, especially in tropical and sub-tropical regions. The existence of seagrasses is known to support fishing activities, shellfish communities and other invertebrate biota.
Method: This study is a descriptive study to reveal information about environmental characteristics, and associations of seagrasses with gastropods.
Results: The study found a class of gastropods, 10 species namely Strombus variabilis, Strombus microurceus, Nassariusl uridus, Nassarius dorsatus, Strombus urceus, Cypraea annulus, Strombus labiatus, Strombus marginatus, Neritas quamulata, Cypraeratigris. Of the seagrass plants found 4 species, namely Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata. Association values ranged from 4.159-8.85 with positive and negative types. This means that both types of seagrass are often found together or not found together in each observation box.
Conclusion: There is a weak association between seagrass and gastropods in the coastal waters of Tiouw State. The association of gastropod types with seagrass species is found in 10 types of gastropods and 4 types of seagrasses in the waters of the Tiouw State coast
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Short, Frederick T., i Sandy Wyllie-Echeverria. "Natural and human-induced disturbance of seagrasses". Environmental Conservation 23, nr 1 (marzec 1996): 17–27. http://dx.doi.org/10.1017/s0376892900038212.
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SummaryMany natural and human-induced events create disturbances in seagrasses throughout the world, but quantifying losses of habitat is only beginning. Over the last decade, 90000 ha of seagrass loss have been documented although the actual area lost is certainly greater. Seagrasses, an assemblage of marine flowering plant species, are valuable structural and functional components of coastal ecosystems and are currently experiencing worldwide decline. This group of plants is known to support a complex trophic food web and a detritus-based food chain, as well as to provide sediment and nutrient filtration, sediment stabilization, and breeding and nursery areas for finfish and shellfish.We define disturbance, natural or human-induced, as any event that measurably alters resources available to seagrasses so that a plant response is induced that results in degradation or loss. Applying this definition, we find a common thread in many seemingly unrelated seagrass investigations. We review reports of seagrass loss from both published and ‘grey’ literature and evaluate the types of disturbances that have caused seagrass decline and disappearance. Almost certainly more seagrass has been lost globally than has been documented or even observed, but the lack of comprehensive monitoring and seagrass. mapping makes an assessment of true loss of this resource impossible to determine.Natural disturbances that are most commonly responsible for seagrass loss include hurricanes, earthquakes, disease, and grazing by herbivores. Human activities most affecting seagrasses are those which alter water quality or clarity: nutrient and sediment loading from runoff and sewage disposal, dredging and filling, pollution, upland development, and certain fishing practices. Seagrasses depend on an adequate degree of water clarity to sustain productivity in their submerged environment. Although natural events have been responsible for both large-scale and local losses of seagrass habitat, our evaluation suggests that human population expansion is now the most serious cause of seagrass habitat loss, and specifically that increasing anthropogenic inputs to the coastal oceans are primarily responsible for the world-wide decline in seagrasses.
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Wardono, Suko, Elland Yupa Sobhytta, I. Gusti Ngurah Agung Dhananjaya, Rodo Lasniroha, Yuniarti Karina Pumpun, Mochammad Miftakhul Mashuda, Dewa Gde Tri Bodhi Saputra i Permana Yudiarso. "Association Analysis of Seagrass Coverage and Human Activities in Nusa Lembongan". Jurnal Biodjati 7, nr 2 (30.11.2022): 247–58. http://dx.doi.org/10.15575/biodjati.v7i2.20307.
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Nusa Lembongan has high marine biodiversity, including seagrass. Seagrass is a plant that lives submerged in a marine or estuary water that functions as a nursery ground, trapping sediment, and beach protector, so it is important to know the condition of seagrass coverage, especially in Nusa Lembongan for managing the Nusa Penida Marine Protected Area. This study aimed to understand the condition of seagrass coverage and the factors influencing the existence of its ecosystem in Nusa Lembongan. According to reslut in two stations, it was found that six of the twelve types of seagrasses in Indonesia, namely Enhalus acoroides, Thalassia hemprichii, Cymodocea serrulata, Cymodocea rotundata, Halodule pinifolia, and Halophila ovalis. From the two stations (LMB01 and LMB02), the total seagrass coverage was 38.10±30.98% or the medium category. The seagrass communities in the station areas were generally formed by 3 types of seagrasses; Thalassia hemprichii, Cymodocea serrulata, and Cymodocea rotundata. LMB02 has higher seagrass coverage than LMB01. The seagrass coverage is inversely proportional to the intensity of human activity.
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Ramesh, Chatragadda, i Raju Mohanraju. "Seagrass Ecosystems of Andaman and Nicobar Islands: Status and Future Perspective". Environmental and Earth Sciences Research Journal 7, nr 4 (31.12.2020): 169–74. http://dx.doi.org/10.18280/eesrj.070407.
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Seagrasses are unique marine flowering plants that play an important ecological role by yielding primary production and carbon sequestration to the marine environment. Seagrass ecosystems are rich in organic matter, supporting the growth of bio-medically important epi and endophytic microorganisms and harbor rich marine biodiversity. They are an essential food source for endangered Andaman state animal Dugongs. Seagrasses are very sensitive to water quality changes, and therefore they serve as ecological bio-indicators for environmental changes. The benthic components in and around the seagrass beds support a significant food chain for other Micro and organisms apart from fishery resources. The epiphytic bacterial communities of the leaf blades support the sustenance against the diseases. Recent reports have shown that the loss of seagrass beds in tropical and temperate regions emphasizes the depletion of these resources, and proper management of seagrass is urgent. The decline of seagrass will impact primary production, biodiversity, and adjacent ecosystems, such as reefs. Therefore, restoring the seagrass meadows could be possible with effective implementing management programs, including seagrass meadows in marine protected areas, restoration projects, seagrass transplantation, implementation of legislative rules, monitoring coastal water quality and human activities in the coastal zone. Lacunas on the seagrass ecosystem management in Andaman & Nicobar Islands are addressed.
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Mascarinas, Honey Jane, i Otadoy Julie B. "Seagrass Diversity and Distribution in Maribojoc Bay, Bohol, Philippines". American Journal of Environment and Climate 1, nr 1 (3.05.2022): 12–19. http://dx.doi.org/10.54536/ajec.v1i1.217.
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Seagrasses are major parts of coastal and marine biodiversity. Unfortunately, these aquatic plants and their ecological values are virtually unknown to many Filipinos. This study assessed the seagrasses in Maribojoc Bay, particularly in the coastal areas of the three municipalities, namely Maribojoc, Dauis, Panglao, and the City of Tagbilaran. Ecological assessments were conducted to determine the composition, abundance, distribution, percent cover, diversity, dominance, and evenness of seagrass species. Eight sampling sites were surveyed from October to December 2020. Seven seagrass species were identified, with Thalassia hemprichii as the most abundant (52.79%). There was a significant difference (p>0.05) in seagrass species relative abundance. The Shannon diversity index implies low diversity (H’=1.40) of seagrass species. High dominance (2.98) and low evenness (0.72) were attributed to the high abundance of T. hemprichii in the seagrass beds. The seagrass coverage was characterized by patchy and continuous meadows, with percentage cover ranging from 17.45% (poor) – 60% (good). Maribojoc Bay had a seagrass percentage cover of 38.65%, which can be classified under “fair” conditions. Seagrass community structure implies sparse coverage and low diversity, probably due to the deterioration of once-continuous meadows. However, further studies concerning seagrass communities are recommended in order to implement rehabilitation program or improve current management in Maribojoc Bay.
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Irwan, Anisa, Calvyn F. A. Sondak, Sandra O. Tilaar, Esther D. A. Angkouw, Agung B. Windarto i Billy Th Wagey. "STUKTUR KOMUNITAS PADANG LAMUN DI SEKITAR DESA TOSEHO KECAMATAN OBA KOTA TIDORE KEPULAUAN". JURNAL PESISIR DAN LAUT TROPIS 11, nr 3 (10.01.2024): 233–42. http://dx.doi.org/10.35800/jplt.11.3.2023.53666.
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Seagrasses are flowering plants that are fully adapted to being immersed in seawater. Seagrass plants consist of rhizomes, leaves and roots. This study aims to identify the types of seagrasses and determine the structure of seagrass community. This research was conducted in July 2023 around Toseho Village, Oba Subdistrict, Tidore City Kepulaun with coordinate points on transect 1 which is 0°21'20.72 "U, 127°38'58.46 "T. on transect 2 0°21'21.78 "U, 127°38'57.32 "T and on transect 3 which is 0°21'22.86 "U, 127°38'56.14 "T. The method used in this research is quadrant line transect method. Based on the results of the study, it can be concluded that there are 6 types of seagras in Toseho Village, namely Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, Halophila ovalis, Halodule univervis and Sryngodium isoetifolium. From the results of data analysis, it was found that Thalassia hemprichii was the most dominating seagrass species in each of the 3 quadrant transects. Seagrass species diversity in Toseho Village has a medium level of species diversity (1 ≤H'≤3 Medium species diversity).Keywords: Seagrass, Community Structure, Toseho Village
ABSTRAKLamun merupakan tumbuhan berbunga yang sepenuhnya menyesuaikan diri untuk terbenam dalam air laut. Tumbuhan lamun terdiri dari rhizome, daun dan akar. Penelitian ini bertujuan untuk mengidentifikasih jenis-jenis lamun dan mengetahui struktur komunitas padang lamun. Penelitian ini dilakukan pada bulan Juli 2023 di sekitar Desa Toseho Kecamatan Oba Kota Tidore Kepulaun dengan titik kordinat pada transek 1 yaitu 0°21’20.72”U, 127°38’58.46”T. pada transek 2 0°21’21.78”U, 127°38’57.32”T dan pada transek 3 yaitu 0°21’22.86”U, 127°38’56.14”T. Metode yang digunakan dalam penelitian ini yaitu metode line transek kuadran. Berdasarkan hasil penelitian maka dapat disimpulkan bahwa ditemukannya 6 jenis lamun di Desa Toseho yaitu Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, Halophila ovalis, Halodule univervis dan Sryngodium isoetifolium. Dari hasil analisi data didapatkan bahwa Thalassia hemprichii merupakan jenis lamun yang paling mendominasi di setiap 3 transek kuadran. Kenekaraman jenis lamun di Desa Toseho memiliki tingkat keanekaragaman jenis sedang (1 ≤H′ ≤ 3 Keanekaragaman spesies sedang).Kata Kunci: Seagrass, Community Structure, Toseho Village
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Hirst, A. J., K. Giri, D. Ball i R. S. Lee. "Determination of the physical drivers of Zostera seagrass distribution using a spatial autoregressive lag model". Marine and Freshwater Research 68, nr 9 (2017): 1752. http://dx.doi.org/10.1071/mf16252.
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Seagrass mapping has become a key tool in understanding the causes of change in seagrass habitats. The present study demonstrates a method for examining relationships between seagrass habitat polygons and environmental data generated by hydrodynamic, wave, catchment and dispersion models. Seagrass abundance data are highly spatially autocorrelated and this effect was corrected using a spatially simultaneous autoregressive lag model (SSARLM). The physical processes that determine the spatial distribution of seagrass in Port Phillip Bay, Australia, were investigated by examining the links between seagrass distribution and abundance and broadscale hydrodynamic (waves, currents), physical (light, depth, salinity and temperature) and catchment (nutrient and suspended sediment concentrations) processes. The SSARLM indicated that the distribution of Zostera spp. meadows is principally constrained by two physical thresholds, namely, wave height or exposure and light. The former excludes seagrasses from colonising wave-exposed coastlines, whereas the latter directly determines the depth profile of seagrasses through its influence on light availability. In total, 95% of all seagrass occurred within grid cells with a mean significant wave height of <0.38m and a mean percentage irradiance of >33% surface levels. By comparison, variation in water quality, represented by variables such as modelled total nitrogen, suspended solids or salinity, had little influence on seagrass distribution.
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Lee, Kevin M., Megan Ballard, Kyle Capistrant-Fossa, Andrew R. McNeese, Colby W. Cushing, Thomas S. Jerome, Preston S. Wilson i Kenneth H. Dunton. "Temporal dependence of acoustic propagation in a seagrass meadow over diurnal and annual timescales". Journal of the Acoustical Society of America 153, nr 3_supplement (1.03.2023): A26. http://dx.doi.org/10.1121/10.0018032.
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Seagrasses serve major ecological roles in biodiversity promotion, coastal protection, and nutrient cycling. Furthermore, seagrasses have been proposed as a nature-based solution to mitigate effects of climate change due to their capacity for sequestering marine carbon. Current global estimates of seagrass coverage are uncertain; therefore, developing improved methods to assess seagrass coverage and rates of decline are critical to promote sustainable seagrass conservation efforts. Acoustic propagation in seagrass meadows is highly sensitive to oxygen bubble production via photosynthesis and gas volumes encapsulated within seagrass tissue, both acting as biophysical markers. This paper discusses an acoustic method to monitor seagrass oxygen production and biomass with high temporal resolution and over long time-scales. An 18-month acoustic propagation experiment was conducted in a seagrass meadow located in a shallow bay on the Texas Gulf of Mexico Coast. A piezoelectric sound source transmitted broadband frequency-modulated chirps (0.5–100 kHz) every ten minutes, and the signal was measured on horizontal hydrophone array. Dissolved oxygen, photosynthetically active radiation, water temperature, salinity, and depth were concurrently measured with oceanographic probes. Additionally, cores were collected for point-estimates of seagrass biomass. Our work demonstrates that acoustic propagation offers a valuable alternative to experimental measurements of photosynthesis. [Work sponsored by NSF.]
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Roem, Muhamad, Retno Setianingrum i Encik Weliyadi. "ASSOCIATION BETWEEN ECHINOID AND SEAGRASS COMMUNITY IN DERAWAN ISLAND WATERS". Journal of Aquatropica Asia 7, nr 2 (1.12.2022): 104–16. http://dx.doi.org/10.33019/joaa.v7i2.3608.
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Sea urchins a biota that is often associated with seagrasses were often found in seagrass beds. The objectives of this research were to discover the condition of sea urchins and seagrass, such as diversity, uniformity, dominance in sea urchins, density, and cover on seagrass, and related to variables in this research. This research was conducted on Derawan Island. The research method that was used is a 5m x 5m (sea urchin) quadrate and 0.5m x 0.5m (seagrass) placed intentionally on 2 stations with a total of 30 quadrats. The results found 3 species of sea urchins and 4 species of seagrass. At station 1 abundance of sea urchins is 2.94 individual/m2 whereas at station 2 is 0,28 individual/m2. At station 1 seagrass density 117,33 shoot/m2 whereas station 2 is 120,13 shoot/m2. Seagrass cover at station 1 is 58,75% and at station 2 is 60,28%. The dominant sea urchin species is Diadema setosum with the following diversity values H'=0,36, E=0,3, and C=0.81. There was no significant difference between variables at each station except temperature (0.020<0.05) and DO (0.027<0.05). Variables that were correlated with sea urchins in the seagrass ecosystem are nitrate, salinity, phosphate, temperature, and pH. The association with seagrasses in Derawan Island is positive.
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Bongga, Marthen, Calvyn F. A. Sondak, Deisle RH Kumampung, Kakaskasen A. Roeroe, Sandra Olivia Tilaar i Joudy Sangari. "KAJIAN KONDISI KESEHATAN PADANG LAMUN DI PERAIRAN MOKUPA KECAMATAN TOMBARIRI KABUPATEN MINAHASA". JURNAL PESISIR DAN LAUT TROPIS 9, nr 3 (4.10.2021): 44. http://dx.doi.org/10.35800/jplt.9.3.2021.36519.
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Seagrass ecosystems services in the coastal waters are included as primary producers, nutrient recycler, bottom stabilizers, sediment traps, and erosion barriers. Gleaning fisheries in seagrass bed in Mokupa waters could cause damage on seagrass, that can be marked by changes in seagrass cover. The purposes of this study were to identify the types of seagrasses and to determine the health condition of seagrass bed ecosystem in Mokupa waters. The research method used in this study is quadrat transect method. Data collection was carried out by laid three transects (100 m) with distance between each transect was 50 m. A square frame (50×50 cm2) which is divided into 4 squares is placed on the right side of the transect, with 10 m distance between frame. This study found four types of seagrasses, namely Enhalus acoroides, Thalassia hemprichii, Halodule pinifolia and Halophila ovalis. E. acoroides have the highest percentage cover (16.19%) followed byT. hemprichii (6.91%), H. pinifolia (4.50%) and H. ovalis (1.56%) respectively. Seagrass cover in the study area is considered medium (26-50%) while the health condition was poor (29.25%).
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Sidi Cheikh, Mohamed Ahmed, Salomão Bandeira, Seydouba Soumah, Gnilane Diouf, Elisabeth Mayé Diouf, Omar Sanneh, Noelo Cardoso i in. "Seagrasses of West Africa: New Discoveries, Distribution Limits and Prospects for Management". Diversity 15, nr 1 (21.12.2022): 5. http://dx.doi.org/10.3390/d15010005.
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The onset of a major seagrass initiative in West Africa enabled important seagrass discoveries in several countries, in one of the least documented seagrass regions in the world. Four seagrass species occur in western Africa, Cymodocea nodosa, Halodule wrightii, Ruppia maritima and Zostera noltei. An area of about 62,108 ha of seagrasses was documented in the studied region comprising seven countries: Mauritania, Senegal, The Gambia, Guinea Bissau, Guinea, Sierra Leone and Cabo Verde. Extensive meadows of Zostera noltei were recorded for the first time at Saloum Delta, Senegal, which represents the new southernmost distribution limit of this species. This paper also describes the seagrass morphology for some study areas and explores the main stressors to seagrasses as well as conservation initiatives to protect these newly documented meadows in West Africa. The produced information and maps serve as a starting point for researchers and managers to monitor temporal and spatial changes in the meadows’ extent, health and condition as an efficient management tool.
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Khalifa, Muta Ali, Ani Rahmawati, Forcep Rio Indaryanto, Luky Adrianto, Syamsul Bahri Agus, Fery Kurniawan, Aldi Agus Setiawan, Desy Aryani i Agustin Rustam. "The Impact of Tsunami on Seagrass Ecosystem in Tanjung Lesung, Banten, Indonesia". Omni-Akuatika 16, nr 3 (30.12.2020): 78. http://dx.doi.org/10.20884/1.oa.2020.16.3.859.
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The Sunda Strait Tsunami (end of 2018) has an impact on the seagrass ecosystem in Tanjung Lesung. This paper described the seagrass ecosystem’s changes after the tsunami disaster. Sentinel-2 satellite image processing in 2018 and 2019 was used to see changes in the seagrass area. The field data were collected from May–July 2019, including the types of seagrass ecosystems based on data seagrass existence, density and biomass. Then, the seagrass sample was analyzed biomass after the tsunami disaster. The results showed that the data from 2018 – 2019 showed decreased seagrass area from 105.86 to 77.07 ha. Seagrass density dropped quite dramatically, and the species of Halodule uninervis was no longer found. The ratio of after tsunami BG/AbG dry biomass has doubled compared to before the tsunami, which indicates the seagrass's lower biomass is higher than the upper part allegedly due to tsunami impacts. Based on the results obtained, it can be concluded that the seagrass ecosystems changed and disrupted by the tsunami. Keywords: Seagrass, Tanjung Lesung, Tsunami, Sentinel-2
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Rosalina, Dwi, Endang Yuli Herawati, Yenny Risjani i Muhammad Musa. "KEANEKARAGAMAN SPESIES LAMUN DI KABUPATEN BANGKA SELATAN PROVINSI KEPULAUAN BANGKA BELITUNG". EnviroScienteae 14, nr 1 (28.04.2018): 21. http://dx.doi.org/10.20527/es.v14i1.4889.
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Marine area which is planted by seagrass called as seagrass beds. Seagrass is one of the typical ecosystems in marine waters. Bangka Belitung Province is one of the areas in Indonesia that has seagrass ecosystem. This study aims to determine the diversity, density, and coverage area of seagrass beds in the waters of South Bangka Regency. The research was conducted in Tukak, Tanjung Kerasak, and Tanjung Kemirai. The data is collected using quadratic transect method and also data of physics-chemical parameters such as temperature, salinity, pH, depth, velocity and water substrate. The results of the research showed that 7 species of seagrasses in South Bangka Regency are Cymodocea serrulata, Cymodocea rotundata, Halodule uninervis, Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium and Halophila minor. Seagrass in Lempeng waters which has the highest density is Cymodocea serrulata, about 58 ind/m2. The highest frequency of seagrass species in Tukak is Thalassia hemprichii about 1%. Seagrass species of Cymodocea serrulata has the highest cover percentage in Lempeng waters about 29.56%.
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Purvis, Danielle, i Narriman Jiddawi. "Seagrass cover reduction in Zanzibar from 2006 to 2019". Western Indian Ocean Journal of Marine Science 22, nr 1 (12.05.2023): 1–14. http://dx.doi.org/10.4314/wiojms.v22i1.1.
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Seagrass meadows are abundant in Zanzibar, Tanzania and provide essential ecosystem services, yet they have been less researched or protected than other marine ecosystems. Evidence suggests that anthropogenic impacts, such as seaweed farming, small-scale fishing, and tourism, are their greatest threats. Using geographic information systems (GIS) to estimate seagrass cover, this study conducted Spearman’s rank correlation analyses to estimate correlations between the scale of seaweed farming, fishing, and tourism or the implementation of marine protected area (MPA) management plans, and the change in percent of seagrass cover from 2006 to 2019. On average, seagrass cover decreased by 10.98 % over this period. The scale of tourism was negatively correlated with seagrass cover (rs (9) = -0.64, p = 0.044). No other variables were correlated with declines, though seaweed farming had a weak protective effect on seagrass cover (rs(9) = 0.28, p = 0.426). To improve the management of seagrass meadows, plans must identify seagrasses as critical ecosystems, expand seagrass restoration projects, and address harmful practices in the tourism industry.
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Omollo, Derrick, Virginia Wang’ondu, Michael Githaiga, Daniel Gorman i James Kairo. "The Contribution of Subtidal Seagrass Meadows to the Total Carbon Stocks of Gazi Bay, Kenya". Diversity 14, nr 8 (11.08.2022): 646. http://dx.doi.org/10.3390/d14080646.
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Seagrass beds occur globally in both intertidal and subtidal zones within shallow marine environments, such as bays and estuaries. These important ecosystems support fisheries production, attenuate strong wave energies, support human livelihoods and sequester large amounts of CO2 that may help mitigate the effects of climate change. At present, there is increased global interest in understanding how these ecosystems could help alleviate the challenges likely to face humanity and the environment into the future. Unlike other blue carbon ecosystems, i.e., mangroves and saltmarshes, seagrasses are less understood, especially regarding their contribution to the carbon dynamics. This is particularly true in regions with less attention and limited resources. Paucity of information is even more relevant for the subtidal meadows that are less accessible. In Kenya, much of the available information on seagrasses comes from Gazi Bay, where the focus has been on the extensive intertidal meadows. As is the case with other regions, there remains a paucity of information on subtidal meadows. This limits our understanding of the overall contribution of seagrasses in carbon capture and storage. This study provides the first assessment of the species composition and variation in carbon storage capacity of subtidal seagrass meadows within Gazi Bay. Nine seagrass species, comprising of Cymodocea rotundata, Cymodocea serrulata, Enhalus acoroides, Halodule uninervis, Halophila ovalis, Halophila stipulacea, Syringodium isoetifolium, Thalassia hemprichii, and Thalassodendron ciliatum, were found. Organic carbon stocks varied between species and pools, with the mean below ground vegetation carbon (bgc) stocks (5.1 ± 0.7 Mg Cha−1) being more than three times greater than above ground carbon (agc) stocks (0.5 ± 0.1 Mg Cha−1). Mean sediment organic carbon stock (sed Corg) of the subtidal seagrass beds was 113 ± 8 Mg Cha−1. Combining this new knowledge with existing data from the intertidal and mangrove fringed areas, we estimate the total seagrass ecosystem organic carbon stocks in the bay to be 196,721 Mg C, with the intertidal seagrasses storing about 119,790 Mg C (61%), followed by the subtidal seagrasses 55,742 Mg C (28%) and seagrasses in the mangrove fringed creeks storing 21,189 Mg C (11%). These findings are important in highlighting the need to protect subtidal seagrass meadows and for building a national and global data base on seagrass contribution to global carbon dynamics.
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ERNAWATI, Ni Made, i Made Ayu Pratiwi. "STRUKTUR KOMUNITAS EKOSISEM PADANG LAMUN PADA DAERAH INTERTIDAL DI PANTAI SANUR, BALI". ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) 12, nr 1 (31.05.2018): 50. http://dx.doi.org/10.24843/ejes.2018.v12.i01.p07.
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Coastal ecosystem is a productive ecosystem and has high ecological and economic value. Coastal ecosystem components, consist of coral reefs, seagrass beds, mangroves and various types of biota. The seagrass ecosystem is one of the most unique coastal ecosystems because the seagrass can live well in high salinity conditions. Seagrass ecosystem in Bali Island has many adventages and widely used for marine tourism activities. One of the marine tourism sites, that take advantage of the beauty of the seagrass ecosystem in Bali is Sanur beach. The utilization of seagrass ecosystem for marine tourism activities might be influence the structure of seagrass community. Therefore, the study about Community Structure of Seagrass Ecosystem at Intertidal Area in Sanur Beach is very important to carried out in order to investigate the structure of the seagrass ecosystem community. Samples were taken in the intertidal zone at six observation stations. At each station, it was conducted three times perpendicular repetition to the shoreline. Seagrass observation was done by using quadratic transect (50 × 50 cm). The types of seagrass found in Sanur Beach were 6 species, namely Cymodocea serrulata, Cymodocea rotundata, Halophila ovalis, Halodule uninervis, Halodule pinifolia, and Syringodium isoetifolium. Cymodocea serrulata is a seagrass-type found in every observation station, and it able to live well in Sanur Beach water characteristics. The highest average of seagrass species density is shown by the Cymodocea serrulata species of 175.11 stands/m2, while, the highest average of seagrass species density is shown by the Halodule pinifolia species of 27.33 stands/m2. The average of diversity, uniformity and dominance index at Sanur Beach reach 0.8682; 0.7347; and 0.4987, respectively. In Sanur Beach area, the seagrass has high uniformity value and stable community. The instability community has been found at station 2 when the dominance of Cymodocea serrulata species was occurred.
Keywords: Community structure; Sanur Beach; seagrasse cosystem
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Ardyanti, Agustina Aries, Roni Bawole i Yuanike Kaber. "Diversity of Seagrass Along Two Coast Line Villages in The Regency of Biak Numfor: A Comparative Study". Asian Journal of Environment & Ecology 22, nr 4 (8.11.2023): 16–27. http://dx.doi.org/10.9734/ajee/2023/v22i4504.
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The Biodiversity Assessment of Seagrass Ecosystem in Orwer and Ambroben Waters, Biak Numfor Regency, Papua Province is very important for a baseline study of the ecosystem health of seagrass beds. The ecological function of seagrass ecosystems is to stabilize the seabed, provide food and habitat for other marine life, and maintain water quality. The research conducted aims to (1) determine the types of seagrasses, density, and percentage of seagrass cover in Orwer and Ambroben waters, and (2) find out the characteristics of aquatic environmental parameters that play an important role in determining the health status of seagrass meadow ecosystems. Based on the results of the research has been found as many as four types of seagrasses are in Orwer waters, namely Halodule pinifolia, Cymodocea rotundata, Thalassia hemprichii, and Halophila ovalis. In Ambroben waters have been found as many as 7 types of seagrass, namely Halodule pinifolia, Halodule uninervis, Cymodocea rotundata, Syringodium isoetifolium, Enhalus acoroides, Thalassia hemprichii and Halophila ovalis. The average density per seagrass species in Orwer waters is higher (2101 ind/m2) compared to Ambroben waters (1553 ind/m2). The percentage of seagrass ecosystem cover in Orwer is higher (94.44%) than in Ambroben waters (91.53%). The characteristics of aquatic health indicators for seagrass ecosystems in Orwer and Ambroben waters show almost the same range of values, namely temperatures ranging from 29.47-29.97, salinity 33.27-33.97 oo/oo, and pH 7.57-8.46, the dissolved oxygen parameter shows different values between the two waters. Oxygen levels in Orwer waters are 10.47-14.37 mg / L, while Oxygen levels in Ambroben waters are 7.47-11.10 mg / L. Based on these results, it shows that both waters are still included in the category of healthy waters and meet the quality standard criteria for life requirements for seagrass ecosystems.
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Nguyen Xuan, Hoa, Nhu Thuy Nguyen Nhat i Hieu Nguyen Trung. "Current status and variation trend of seagrass beds in coastal water of Son Tra peninsula, Da Nang city". Tạp chí Khoa học và Công nghệ Biển 21, nr 2 (30.06.2021): 183–89. http://dx.doi.org/10.15625/1859-3097/16405.
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Species composition of seagrasses in coastal water of Son Tra peninsula was less diverse, with three species identified. Halophila ovalis was dominant. The seagrass beds are mainly distributed in Bai Nom and Bai But, with a total area of about 1 ha. The seagrass beds had been seriously degraded in both size and structure. Approximately 9 ha of seagrass beds (90% of total area) disappeared compared with data of 2005. Halophila ovalis had only been distributed at a depth of 2–3 m. Coverage, shoot density, and biomass of seagrass beds had also decreased.
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Siahaya, Chalvin Salmon, Prelly Marsell Jolanda Tuapattinaya i Stevin Melay. "DIVERSITY PHENETICS OF TYPES SEAGRASS IN VILLAGE POKA BEACH MALUKU BASED ON MORPHOMETRICS". RUMPHIUS Pattimura Biological Journal 4, nr 2 (29.09.2022): 062–66. http://dx.doi.org/10.30598/rumphiusv4i2p062-066.
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This research aims to determine the phenetic diversity of seagrass species in the coastal waters of Poka Village based on morphometrics. This research is a type of descriptive research, in which morphometric measurements are carried out to determine the phenetic diversity of seagrass species. Meanwhile, for kinship relationships between seagrasses. Software is used past 4.0. The results of this research were that four types of seagrass were found, namely Thalasssia hemprichii, Enhalus acoroides, Halophila pinifolia and Halophila ovalis. This indicates that the Poka Village beach has a high phenetic diversity of seagrass species with varying morphometrics for each character and type, which is influenced by the type of substrate and environmental parameters. Seagrasses that are closely related, namely, Thalasssia hemprichii and Enhalus acoroides are in one monophyletic group (ingroup) and are very closely related. Likewise with Halodule pinifolia and Halophila ovalis.
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Tahapary, Rian, Hasan Tuaputty, Sintje Liline, Tri Santi Kurnia i Muhammad Tarmizi Kubangun. "Keanekaragaman Jenis dan Kepadatan Ikan di Padang Lamun Pantai Desa Akoon Kecamatan Nusalaut Kabupaten Maluku Tengah". bionature 20, nr 2 (8.12.2019): 140. http://dx.doi.org/10.35580/bionature.v20i2.11285.
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Abstract. One of the ecological roles of seagrass beds is as fish habitat and the presence of seagrasses can affect the diversity and density of fish in a water. Distribution of seagrass vegetation in the waters of the village of Akoon is quite extensive with conditions that are also quite diverse, allowing the many types of fish that live in the seagrass beds in the village of Akoon. Nusalaut, Central Maluku Regency. The results of the study describe the types of fish that are in the seagrass beds in the village of Akoon are 17 species with 80 individuals. Fish species diversity index in the seagrass beds in Akoon village, Nusalaut sub-district was 2,434, evenness index was 0.859, and wealth index was 1,900. Fish in seagrass beds in Akoon village, Nusalaut sub-district have a density value of 0.2 ind / m2. Keywords: diversity, density, seagrass fish, Akoon Village
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Irawan, Andri, i Noorsalam R. Nganro. "DISTRIBUTION OF SEAGRASSES IN INNER AMBON BAY". Jurnal Ilmu dan Teknologi Kelautan Tropis 8, nr 1 (11.11.2016): 99–114. http://dx.doi.org/10.29244/jitkt.v8i1.12499.
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ABSTRACTExcessive sedimentation in Inner Ambon Bay (IAB) is alleged to cause the degradation of seagrass ve-getation in the area. To get a clearer picture about the matter, we conducted a field study in October 2010 - January 2011 to describe the distribution and density of seagrass at several locations in IAB with different conditions of sedimentation levels. Data were collected using transects perpendicular to the coastline along the seagrass vegetation. The results showed that there were six species of seagrass which were spreaded unevenly. At the locations with high sedimentation, we found the formation of monospecies seagrass vegetation. Conversely, at the locations with low sedimentation, we found the formation of multispecies seagrass vegetation. The distribution and abundance of each species was related to the differences of seagrasses ability to grow in a certain environment and the compe-titiveness among them. Keywords: sedimentation, distribution, seagrass, Inner Ambon Bay
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Zhang, Yong, Xinping Yu, Zuoyi Chen, Qiuzhen Wang, Jiulong Zuo, Shanshan Yu i Ran Guo. "A Mini-Review of Seagrass Bed Pollution". Water 15, nr 21 (27.10.2023): 3754. http://dx.doi.org/10.3390/w15213754.
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Due to climate change and human activities, seagrass is in crisis as the coverage of seagrass declines at an accelerated rate globally. In this paper, the severe challenges of seagrass ecosystem were briefly reviewed, including adverse effects of natural factors and human activities on seagrass beds. The research status of pollutants and pollution in seagrass bed ecosystem was reviewed, the future research directions in related fields were proposed as well. The eutrophication in coastal waters and discharge of pollutants such as sulfide, heavy metals, organic matter and microplastics caused by human activities are important reasons for seagrass loss. In addition, environmental stressors lead to reduced immunity and decreased resistance of seagrass to various pathogens, leading to seagrass wasting diseases. Future studies concerning the influence of novel pollutants, i.e., plastic waste on non-native algae, microorganisms and seagrasses, as well as their interrelationships, will be of vital importance. In addition, researches on seagrass wasting diseases and their pathogens should be much accounted in China, to fill in gaps in related fields and improve the response ability to emergent seagrass diseases. In conclusion, this review was proposed to arouse the concern about the seagrass bed pollution, and provide possible enlightening information for the protection and restoration of this significant ecosystem.
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J. Lee Long, W., R. G. Coles i L. J. McKenzie. "Issues for seagrass conservation management in Queensland". Pacific Conservation Biology 5, nr 4 (1999): 321. http://dx.doi.org/10.1071/pc000321.
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Coastal, reef-associated and deepwater (> 15 m) seagrass habitats form a large and ecologically important community on the Queensland continental shelf. Broad-scale resource inventories of coastal seagrasses were completed in the 1980s and were used in marine park and fisheries zoning to protect some seagrasses. At least eleven of the fifteen known species in the region reach their latitudinal limits of distribution in Queensland and at least two Halophila species may be endemic to Queensland or northeastern Australia. The importance of seagrasses to Dugongs Dugong dugon, Green Turtles Chelonia mydas and commercially valuable prawn fisheries, will continue to strongly influence directions in seagrass research and conservation management in Queensland. Widespread loss of seagrasses following natural cyclone and flood events in some locations has had serious consequences to regional populations of Dugong. However, the impacts to Queensland fisheries are little studied. Agricultural land use practices may exacerbate the effects of natural catastrophic events, but the long-term impacts of nutrients, pesticides and sediment loads on Queensland seagrasses are also unknown. Most areas studied are nutrient limited and human impacts on seagrasses in Queensland are low to moderate, and could include increases in habitat since modern settlement. Most impacts are in southern, populated localities where shelter and water conditions ideal for productive seagrass habitat are often targets for port development, and are at the downstream end of heavily modified catchments. For Queensland to avoid losses experienced by other states, incremental increases in impacts associated with population and development pressure must be managed. Seagrass areas receive priority consideration in oil spill management within the Great Barrier Reef and coastal ports. Present fisheries legislation for marine plant protection, marine parks and area closures to trawl fishing help protect inshore seagrass prawn nursery and Dugong feeding habitat, but seagrasses in deep water do not yet receive any special zoning protection. Efficacy of the various Local, State and Commonwealth Acts and planning programmes for seagrass conservation is limited by the expanse and remoteness of Queensland's northern coast, but is improving through broad-based education programmes. Institutional support is sought to enable community groups to augment limited research and monitoring programmes with local "habitat watch" programmes. Research is helping to describe the responses of seagrass to natural and human impacts and to determine acceptable levels of changes in seagrass meadows and water quality conditions that may cause those changes. The management of loss and regeneration of sea grass is benefiting from new information collected on life histories and mechanisms of natural recovery in Queensland species. Maintenance of Queensland's seagrasses systems will depend on improved community awareness, regional and long-term planning and active changes in coastal land use to contain overall downstream impacts and stresses.
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Meister, Martin, i John J. Qu. "Quantifying Seagrass Density Using Sentinel-2 Data and Machine Learning". Remote Sensing 16, nr 7 (27.03.2024): 1165. http://dx.doi.org/10.3390/rs16071165.
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Seagrasses, rooted aquatic plants growing completely underwater, are extremely important for the coastal ecosystem. They are an important component of the total carbon burial in the ocean, they provide food, shelter, and nursery to many aquatic organisms in coastal ecosystems, and they improve water quality. Due to human activity, seagrass coverage has been rapidly declining, and there is an urgent need to monitor seagrasses consistently. Seagrass coverage has been closely monitored in the Chesapeake Bay since 1970 using air photos and ground samples. These efforts are costly and time-consuming. Many studies have used remote sensing data to identify seagrass bed outlines, but few have mapped seagrass bed density. This study used Sentinel-2 satellite data and machine learning in Google Earth Engine and the Chesapeake Bay Program field data to map seagrass density. We used seagrass density data from the Chincoteague and Sinepuxent Bay to train machine learning algorithms and evaluate their accuracies. Out of the four machine learning models tested (Naive Bayes (NB), Classification and Regression Trees (CART), Support Vector Machine (SVM), and Random Forest (RF)), the RF model outperformed the other three models with overall accuracies of 0.874 and Kappa coefficients of 0.777. The SVM and CART models performed similarly and NB performed the poorest. We tested two different approaches to assess the models’ accuracy. When we used all the available ground samples to train the models, whereby our analysis showed that model performance was associated with seagrass density class, and that higher seagrass density classes had better consumer accuracy, producer accuracy, and F1 scores. However, the association of model performance with seagrass density class disappeared when using the same training data size for each class. Very sparse and dense seagrass classes had replacedhigherbetter accuracies than the sparse and moderate seagrass density classes. This finding suggests that training data impacts machine learning model performance. The uneven training data size for different classes can result in biased assessment results. Selecting proper training data and machine learning models are equally important when using machine learning and remote sensing data to map seagrass density. In summary, this study demonstrates the potential to map seagrass density using satellite data.
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Uku, J., L. Daudi, V. Alati, A. Nzioka i C. Muthama. "The status of seagrass beds in the coastal county of Lamu, Kenya". Aquatic Ecosystem Health & Management 24, nr 1 (2.01.2021): 35–42. http://dx.doi.org/10.14321/aehm.024.01.07.
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Abstract Biodiversity assessments within seagrass beds were conducted in six sites in Lamu, Kenya; namely, Kiweni, Tauzi, Wange, Ntopate, Manda toto and Ngoi. The objective of the assessment was to collect baseline information of the seagrasses of Lamu County in Kenya. Our findings revealed that nine out of the twelve seagrass species found in Kenya were found in the study sites. The dominant seagrass species Thalassodendron ciliatum was found to occur in deeper subtidal areas, while the pioneering species occurred in intertidal shallower areas. Average shoot densities per site ranged from 2.4 ± 1.7 shoots m-2 of Cymodocea serrulata to 1025.9 ± 139.3 shoots m-2 of Syringodium isoetifolium in Ngoi. Canopy heights ranged from 0.1 ± 0.1 cm of Halodule ovalis in Tauzi to 16.3±1.3.5 cm of Syringodium isoetifolium in Ngoi. Although the seagrass species characteristics were much lower than that found in similar mangrove fringed seagrass beds of Gazi Bay, the majority of the fish found in these seagrass areas were invertivores which indicates that these seagrass sites form a refugia for adult fish populations with nursery grounds being located elsewhere. This study forms the first comprehensive assessment of the seagrasses of Lamu and it provides important baseline information on seagrass beds. Such biodiversity information provides important support for decision-making for coastal areas that are targeted for infrastructural development such as Lamu. Biodiversity information of such critical habitats form a critical data base for marine spatial planning and can be used to effectively guide the integration of biodiversity and coastal livelihoods in the sustainable development of Kenya’s coastal areas.
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Laia, Dominikus Yoeli Wilson, Ganang Wibisono, Eddy Handoko, Gita Endang Palufi, Fajar Kurniawan, Syofyan Roni i Muhammad Alrizky Ratno Budiarto. "Seagrass Meadow Distribution Mapping in the Coastal Lagoon of Buan Island, Anambas". Jurnal Kelautan Tropis 26, nr 3 (27.10.2023): 554–64. http://dx.doi.org/10.14710/jkt.v26i3.20450.
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Seagrasses are vital monocotyledonous marine flowering plants that serve as essential food sources for megaherbivores, contribute significantly to organic carbon production, and offer a multitude of crucial ecosystem services. Preserving seagrass habitats is of utmost importance, but the lack of comprehensive spatial data poses challenges to conservation efforts. The Anambas Islands, consisting of 255 small islands in the Natuna Sea, the southern part of the South China Sea, exemplify the scarcity of seagrass data, with the current distribution map only covering the Central and East Siantan region. In this study, our aim was to map the Buan coastal lagoon, where previous visual interpretation of Google Earth imagery suggested the presence of seagrasses. To achieve this, we carried out a drone survey and collected field data to classify and map the substrate types in the study area. The field survey documented four species in the location: T. hemprichii, E. acoroides, H. ovalis and S. isoetifolium, thereby expanding the known seagrass species in Anambas to nine. By employing a pixel-based classification of orthophotos, we achieved a promising overall accuracy of 69.5%. Our findings demonstrated that imageries from the Google Earth platform are viable alternatives for identifying seagrass meadows and can be utilized to support seagrass mapping efforts. This discovery offers valuable support for future seagrass mapping initiatives, especially at a local scale. Ultimately, our study contributes to the broader understanding of seagrass distribution in the Anambas Islands, and emphasizes the importance of further exploration to support conservation efforts in the seagrass ecosystem.
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Vanderklift, MA, RD Pillans, M. Hutton, L. De Wever, GA Kendrick, A. Zavala-Perez, A. Vergés i in. "High rates of herbivory in remote northwest Australian seagrass meadows by rabbitfish and green turtles". Marine Ecology Progress Series 665 (29.04.2021): 63–73. http://dx.doi.org/10.3354/meps13657.
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Herbivory is a key ecological process that often determines the composition and abundance of plants. Estimates of herbivory in seagrass meadows are typically lower than those in other vegetated coastal ecosystems, but herbivory can be intense when large herbivorous vertebrates are abundant. We surveyed rates of herbivory on 2 species of tropical seagrasses (Thalassia hemprichii and Enhalus acoroides), the abundance of herbivorous vertebrates, and the diet of 2 abundant herbivorous vertebrates (the green turtle Chelonia mydas and the rabbitfish Siganus lineatus) in lagoons adjacent to remote islands off northwestern Australia. Rates of herbivory in some deployments of tethered seagrass were more than 1000 times higher than rates of production and were among the highest recorded. Consumption exceeded production in half the deployments (9 of 18). Remote underwater video revealed that S. lineatus was the most abundant herbivore. Stomachs of S. lineatus contained mostly seagrass, and models based on stable isotopes indicated that seagrass was the primary source of nutrition. Stomach contents of C. mydas were more variable, containing seagrass and macroalgae (although the sample size was low), but models based on stable isotopes indicated that seagrass was likely the primary source of nutrition. Multiple lines of evidence suggest that the high rates of herbivory on the seagrasses T. hemprichii and E. acoroides are mainly due to direct consumption by the abundant S. lineatus, and perhaps also C. mydas. Seagrass is the primary contributor to the nutrition of both species.
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Jerome, Thomas S., Megan Ballard, Kevin M. Lee, Colby W. Cushing, Kyle Capistrant-Fossa, Andrew R. McNeese, Preston S. Wilson i Kenneth H. Dunton. "Effective medium modeling of acoustic propagation in a seagrass meadow". Journal of the Acoustical Society of America 153, nr 3_supplement (1.03.2023): A62. http://dx.doi.org/10.1121/10.0018168.
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Seagrasses are foundation species in many coastal ecosystems, but these environments are declining globally due to climate change and other anthropogenic impacts. Ballard et al. [J. Acoust. Soc. Am. 147, 2020] established the efficacy of acoustic remote sensing techniques for seagrass monitoring by exploiting acoustic sensitivity to gas bubbles produced by photosynthesis and gas channels within the seagrass leaves. However, the effects of seagrass on acoustic propagation are not understood with sufficient quantitative detail, and an improved model describing propagation through a mixture of seagrass leaves, free gas bubbles, and seawater is needed to aid in integrating acoustic methods into conservation efforts. This talk provides an overview of developments in the modeling of acoustic propagation through a Thalassia testudinum meadow using a homogeneous effective medium approach to represent the seagrass leaves and seawater. The model accounts for the complex microstructure of seagrass leaves including the encapsulated gas channels and the elastic properties of the seagrass tissue. The model is intended for use in geoacoustic inference algorithms for the overall goal of providing estimates of seagrass productivity and biomass. Candidate effective medium models include 2D cylindrical seagrass leaves and a micromechanical model of a seagrass leaf cross-section. [Work supported by NSF.]
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Dewi, C. S. U., M. Handayani, F. Kurniawan, D. Yona, A. A. Rohenda i M. A. Asadi. "Potential Carbon Stock of Seagrass Biomass in Malang Regency". IOP Conference Series: Earth and Environmental Science 1328, nr 1 (1.04.2024): 012010. http://dx.doi.org/10.1088/1755-1315/1328/1/012010.
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Abstract Research on blue carbon content in seagrass beds also has important implications for coastal ecosystem management. The goals of this research are: (1) To determine the composition of seagrass species; (2) to analyze the health of the seagrass ecosystem; and (3) and to analyze the carbon content stored in seagrass biomass on the coast of Malang Regency. This research was conducted in 2018 at five stations, namely: Kondang Merak Beach (St 1), Balekambang Beach (St 2), Gatra Beach (St 3), Sendangbiru Beach (St 4), and Waru-Waru Beach (St 5) of Malang Regency. The method used to collect data refers to Seagrass Watch. The biomass value of seagrass species can be estimated by measuring the wet weight and dry weight of seagrass. Analysis of carbon content in seagrass biomass can be calculated using a method that refers to The First Nation-Wide Assessment Identifies Valuable Blue-carbon. There are five types of seagrasses found on five beaches in Malang Regency, namely: Halodule pinifolia, Halodule uninervis, Halophila ovalis, Syringodium isotifolium, and Thalassia hemprichii. This seagrass meadow ecosystem is in an unhealthy condition, with a small biomass value. Seagrass beds that are formed only in the form of small spots (1.19 Ha) are known to be able to store carbon of 0.0544 Mg C.
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Reid, T. "Seagrass in Australia. A Strategic Review and Development of a Research and Development Plan". Pacific Conservation Biology 6, nr 2 (2000): 178. http://dx.doi.org/10.1071/pc00178a.
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Australia possesses the highest diversity of seagrasses and the most extensive seagrass meadows world-wide. Unfortunately, Australia also has claim to some of the most significant declines of this habitat over the last 50 years. Seagrass in Australia reflects the shift from viewing seagrass species or even habitats as separate unconnected entities. Instead, it views them as components of larger ecosystems which incorporates the author's aim to develop a comprehensive, ecosystem based management plan.
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Coles, Rob, Fred Short, Miguel Fortes i John Kuo. "Twenty years of seagrass networking and advancing seagrass science: The International Seagrass Biology Workshop Series." Pacific Conservation Biology 20, nr 1 (2014): 8. http://dx.doi.org/10.1071/pc140008.
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SEAGRASSES are a group of some 72 species of marine flowering plants found in the world’s shallow coastal oceans (Green and Short 2003, Short et al. 2011). There is now scientific consensus that they create an important marine habitat not only by themselves, but also as a component of more complex ecosystems within marine coastal zones. Seagrasses contribute to the health of coral reefs and mangroves, salt marshes and oyster reefs (Dorenbosch et al. 2004; Duke et al. 2007; Heck et al. 2008; Unsworth et al. 2008). Seagrasses have high primary productivity and are a basis of many marine food webs through direct herbivory and the through a detrital cycle (Hemminga and Duarte, 2000). They have enormous value in providing nutrients (N and P) and organic carbon to other parts of the oceans, including the deep sea, and they contribute significantly to carbon sequestration (Suchanek et al. 1985; Duarte et al. 2005). Armed with this knowledge today it is interesting to remember that it is only just over a hundred years since scientists first began speculating on the roles and values of seagrass in the marine environment, with the first focus occurring in Europe on eelgrass (Zostera marina). Many at the time discounted seagrass as an important primary producer (den Hartog 1980). It was not until after the 1930s, when vast areas of Zostera marina were lost in the northern hemisphere from a wasting disease that scientists and governments started to understand and investigate the value of seagrass to coastal ecosystems (Milne and Milne 1951). The loss of Zostera marina led to obvious declines in migratory waterfowl, crustaceans, finfish and shellfish populations (Thayer et al. 1984) In response to those concerns about ongoing losses of Zostera marina and other seagrass species, a meeting of scientists in Fairbanks, Alaska in early 1973 decided to coordinate seagrass research globally. This led to the first International Seagrass Workshop being organized and held in Leiden, The Netherlands, later that year. The report of that conference (McRoy and Helfferich 1977) makes interesting reading, looking back from the perspective of the 21st century. There is only one contribution from the southern hemisphere (Larkum 1977) with Australia referred to as a “little known region”. What we now know as the centre of seagrass biodiversity, Insular Southeast Asia and the broader Indo Pacific region, receives no mention at all. A significant and long-lasting outcome of the Leiden meeting was the birth of the journal “Aquatic Botany”.
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Ierodiaconou, Daniel A., i Laurie J. B. Laurenson. "Estimates of Heterozostera tasmanica, Zostera muelleri and Ruppia megacarpa distribution and biomass in the Hopkins Estuary, western Victoria, by GIS". Australian Journal of Botany 50, nr 2 (2002): 215. http://dx.doi.org/10.1071/bt00093.
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Knowledge of the spatial arrangement of the seagrass distribution and biomass within the Hopkins Estuary is an essential step towards gaining an understanding of the functioning of the estuarine ecosystem. This study marks the first attempt to map seagrass distribution and model seagrass biomass and epiphyte biomass along depth gradients by the use of global positioning system (GPS) and geographical information system (GIS) technologies in the estuary. For mapping seagrass in small estuaries, ground-surveying the entire system is feasible. Three species of seagrasses, Heterozostera tasmanica (Martens ex Aschers), Zostera muelleri (Irmisch ex Aschers) and Ruppia megacarpa (Mason), were identified in the Hopkins Estuary. All beds investigated contained a mixed species relationship. Three harvest techniques were trialed in a pilot study, with the 25 × 25-cm quadrat statistically most appropriate. Biomass of seagrasses and epiphytes was found to vary significantly with depth, but not between sites. The average estimate of biomass for total seagrasses and their epiphytes in the estuary in January 2000 was 222.7 g m–2 (dry weight). Of the total biomass, 50.6% or 112.7 g m–2 (dry weight) was contributed by seagrasses and 49.4% of the biomass (110.0 g m–2) were epiphytes. Of the 50.6% of the total biomass represented by seagrasses, 39.3% (87.5 g m–2) were leaves and 11.3% (25.2 g m–2) were rhizomes. The total area of seagrasses present in the Hopkins Estuary was estimated to be 0.4 ± 0.005 km2, with the total area of the estuary estimated to be 1.6 ± 0.02 km2 (25% cover). The total standing crop of seagrasses and epiphytes in the Hopkins Estuary in January 2000 was estimated to be 102.3 ± 57 t in dry weight, 56% (56.9 ± 17 t, dry weight) seagrasses and 44% (45.4 ± 19 t, dry weight) epiphytes. Of the seagrass biomass, 39% (39.7 ± 13 t, dry weight) was contributed by leaves and 17% (17.3 ± 7 t, dry weight) by rhizomes.
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Lanuru, Mahatma, Rohani Ambo-Rappe, Khairul Amri i Susan L. Williams. "Hydrodynamics in Indo-Pacific seagrasses with a focus on short canopies". Botanica Marina 61, nr 1 (26.01.2018): 1–8. http://dx.doi.org/10.1515/bot-2017-0037.
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Abstract Seagrass hydrodynamic regimes are important to understand and also to guide seagrass restoration, which is of great interest in Indonesia because of environmental threats to the exceptionally high seagrass species richness. Hydrodynamic regimes influence the physical stability of seagrass beds, sedimentation rates, and the advection of nutrients and food to seagrasses and associated organisms. In a flume, we determined the effect of canopies of Cymodocea rotundata, Enhalus acoroides, Halodule uninervis, Syringodium isoetifolium and Thalassia hemprichii on water velocity, turbulence, turbulence intensity and shear velocity. The taller canopies of Enhalus and Cymodocea slowed water flow, but the shorter canopies (<5 cm) had little effect. Seagrasses did not influence turbulence and turbulence intensity (turbulence normalized to mean velocity) but they reduced shear velocity U*. Our results indicate that Enhalus is a good candidate for transplantation in terms of reducing mean water flow and shear velocities, but that Halodule should also be considered as it also reduced shear velocities and it spreads quickly after transplantation. Our results extend the understanding of seagrass-hydrodynamic relationships to include very short canopies, unlike the taller canopies studied to date.
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Atmaja, Putu Satya Pratama, Dietriech G. Bengen i Hawis H. Madduppa. "The Second Skin of Seagrass Leaves: A Comparison of Microalgae Epiphytic Communities Between Two Different Species Across Two Seagrass Meadows in Lesser Sunda Islands". Tropical Life Sciences Research 32, nr 2 (29.06.2021): 97–119. http://dx.doi.org/10.21315/tlsr2021.32.2.7.
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Epiphytes as the important features in the seagrass ecosystems have been studied widely, and their functions as a primary producer, influence rates of herbivory grazer, and prevent seagrass leaf from desiccation is well known. However, patterns and distribution among seagrasses especially in Indonesia, which was known as hotspot marine biodiversity is not well understood. Therefore, this study aimed to examined epiphytic assemblages on two seagrass species with different morphological and longevity, Enhalus acoroides and Cymodocea rotundata, in two different meadows (conservation area and non-conservation area) in Lesser Sunda Islands (Bali and Lombok). A total of 22 taxa of microalgae epiphytes species were identified from eight sites and 2 different species of seagrass. The highest number of collected species between class was from Bacillariophyceae (18), followed by Cyanophyceae (3) and Fragilariophyceae (1). Analysis of similarity (ANOSIM) revealed a significant difference of microalgae epiphytes assemblages between sites and seagrasses. Epiphytes assemblages in conservation area were more abundant than non-conservation area, both in Bali and Lombok. On seagrass comparison, Enhalus acoroides showed higher abundance of epiphytes assemblages than those on Cymodocea rotundata. Based on principal component analysis (PCA), this study highlights the microalgae epiphytic communities strongly influenced by seawater temperature, phosphate’s concentration, and pH in sediment. This study also demonstrated that the assemblages of microalgae epiphytic communities affected by differences of seagrass morphological and longevity.
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Jones, Cynthia M. "Can we predict the future: juvenile finfish and their seagrass nurseries in the Chesapeake Bay". ICES Journal of Marine Science 71, nr 3 (4.09.2013): 681–88. http://dx.doi.org/10.1093/icesjms/fst142.
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Abstract The importance of estuarine seagrass beds as nurseries for juvenile fish has become a universal paradigm, especially for estuaries that are as important as the Chesapeake Bay. Yet, scientific tests of this hypothesis were equivocal depending on species, location, and metrics. Moreover, seagrasses themselves are under threat and one-third of seagrasses have disappeared worldwide with 65% of their losses occurring in estuaries. Although there have been extensive studies of seagrasses in the Chesapeake Bay, surprisingly few studies have quantified the relationship between seagrass as nurseries for finfish in the Bay. Of the few studies that have directly evaluated the use of seagrass nurseries, most have concentrated on single species or were of short duration. Few landscape-level or long-term studies have examined this relationship in the Bay or explored the potential effect of climate change. This review paper summarizes the seagrass habitat value as nurseries and presents recent juvenile fish studies that address the dearth of research at the long term and landscape level with an emphasis on the Chesapeake Bay. An important conclusion upon the review of these studies is that predicting the effects of climate change on fishery production remains uncertain.
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Samper-Villarreal, Jimena, i Jorge Cortés. "Seagrass characterization on the southern Pacific coast of Costa Rica: history, vegetation, and environment". Botanica Marina 63, nr 5 (25.10.2020): 429–38. http://dx.doi.org/10.1515/bot-2020-0022.
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AbstractSeagrass conservation and management requires scientific understanding of spatial and temporal variability, information that is currently limited for the Eastern Tropical Pacific (ETP). Here, we analysed seagrass presence based on previous reports, herbarium collections and stakeholder knowledge, combined with field characterization in Golfo Dulce, southern Pacific coast of Costa Rica. Seagrasses were found at multiple locations along a narrow border close to shore and in up to 6 m depth within Golfo Dulce, dating back to 1969. Two seagrass species were found, Halophila baillonii and Halodule beaudettei. Seagrass biomass values for Golfo Dulce (12.0 ± 8.5 g DW m−2) were lower and water nutrient concentrations were higher than previously reported in the gulf. Shoot density (1513 ± 767 shoots m−2) was similar to previous reports. Stable isotope values in seagrass were −11.3 ± 1.0‰ δ13C and 1.2 ± 0.9‰ δ15N; while those in sediments were −26.1 ± 1.3 and 2.5 ± 0.9‰. In Golfo Dulce, isotopic values of both seagrass species do not overlap with other known primary producers. Management strategies should aim to minimize known seagrass stressors, protect potential seagrass habitat, and take into account the dynamic life strategies of the two seagrass species found.
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Marliana, Isnaini, Hilman Ahyadi, Dining Aidil Candri, Immy Suci Rohyani, Sukmaraharja Aulia Rachman Tarigan, Pardede Shinta Trilestari, Sebastian Aviandhika i Sri Puji Astuti. "Estimasi Simpanan Karbon dan Status Kesehatan Padang Lamun di Pulau Kelapa Kabupaten Bima". Bioscientist : Jurnal Ilmiah Biologi 9, nr 1 (30.06.2021): 72. http://dx.doi.org/10.33394/bjib.v9i1.3542.
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The seagrass community are angiosperm plant communities that mostly grow in shallow marine waters. The community has an ecological role and function, both as a habitat for various types of biota and as a carbon sink. The purpose of this study was to determine the type and condition of the seagrass ecosystem in Kelapa Island based on the percentage of cover; and to determine the estimated carbon stocks of seagrasses contained. Seagrass community data collection was carried out in September-October 2020 in the waters of Kelapa Island, Bima Regency, West Nusa Tenggara Province. A quadratic transect was used for data collection of seagrass cover, and analysis of seagrass community cover using the PhotoQuad application, followed by determining the condition of the seagrass community ecosystem, and analysis of estimated carbon storage using the Loss On Ignition (LOI) method. The results showed that there were 4 types of seagrass found, consisting of: Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata, and Halodule pinifolia. The percentage of seagrass cover is 52.31%, because it is less than 60%, the health status of seagrass beds is unhealthy based on the Decree of the Minister of the Environment Number 200 of 2004. Total carbon storage is 16.1 gr.Cm-2. Thalassia hemprichii as the highest carbon storage species was 8.27 gr.Cm-2.
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Salaenoi, Jintana, Sawekwan P, Intanil P i Salaenoi J. "Preliminary Determination of Organic Carbon Content in Seagrass Bed at Ao Pae, Rayong Province, Thailand". International Journal of Oceanography & Aquaculture 8, nr 2 (2024): 1–8. http://dx.doi.org/10.23880/ijoac-16000318.
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Seagrass meadows play crucial roles in delivering ecosystem services to various organisms and environmental systems, particularly in efficiently capturing and storing carbon. Thus, seagrasses are included in plans to address climate change challenges. However, there is limited data on carbon sequestration by seagrass in Thailand, especially in localized areas. Therefore, this study aimed to assess the carbon storage in both sediments and seagrass at Ao Pae, Rayong Province. The analysis focused on sediment depth and the impact of moisture content. Sediment and seagrass samples were collected during the low tide season during May 2022. The sampling area was divided into two zones: one with seagrass presence (9 stations) and another where seagrass was absent (4 stations). Sediment was collected from a depth of 60 cm, divided into six layers of 10 cm each. Results indicated that the highest organic carbon content was observed in sediment at depths of 0-10 cm (22.82±2.08%). Additionally, the organic carbon content showed a significant correlation with sediment moisture content in the area with seagrass presence (p<0.05). Furthermore, the mean belowground organic carbon (1.93±0.29%) exceeded the aboveground carbon (1.66±0.28%), and sediments from stations with seagrass had higher organic carbon content compared to those without seagrass. These findings underscore the potential role of seagrass as a significant carbon sequester in Ao Pae, Rayong Province.
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Leemans, Luuk, Isis Martínez, Tjisse van der Heide, Marieke M. van Katwijk i Brigitta I. van Tussenbroek. "A Mutualism Between Unattached Coralline Algae and Seagrasses Prevents Overgrazing by Sea Turtles". Ecosystems 23, nr 8 (18.02.2020): 1631–42. http://dx.doi.org/10.1007/s10021-020-00492-w.
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AbstractSeagrass meadows are threatened biodiversity hot spots that provide essential ecosystem services. Green sea turtles may overgraze meadows, further enhancing seagrass decline. However, we observed an unexpected, remarkable recovery of seagrasses in a previously overgrazed meadow with abundant unattached branched coralline algae, suggesting that turtle grazing had ceased. We hypothesize that this recovery is due to an effective grazing-protection mutualism, in which the spiny coralline algae structures protect the seagrass meadows from overgrazing, while the seagrasses protect the algae from removal by currents and waves. Removing coralline algae from recovered seagrass plots allowed the turtles to resume grazing, while addition of coralline algae to grazed plots caused cessation of grazing. Coralline algae that were placed on bare sand were quickly displaced by wave action, whereas those placed in grazed or ungrazed seagrass remained. Our experiments demonstrate a grazing-protection mutualism, which likely explains the witnessed recovery of an overgrazed seagrass meadow. To our knowledge, this is the first account of a plant–plant grazing-protection mutualism in an aquatic environment. Our findings show that grazing-protection mutualisms can be vital for the maintenance and recovery of ecosystems shaped by habitat-structuring foundation species, and highlight the importance of mutualisms in coastal ecosystems. As seagrasses, sea turtles and coralline algae share habitats along tropical shores worldwide, the mutualism may be a global phenomenon. Overgrazing is expected to increase, and this mutualism adds a new perspective to the conservation and restoration of these valuable ecosystems.
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Emmclan, Lau Sheng Hann, Muta Harah Zakaria, Shiamala Devi Ramaiya, Ikhsan Natrah i Japar Sidik Bujang. "Morphological and biochemical responses of tropical seagrasses (Family: Hydrocharitaceae) under colonization of the macroalgae Ulva reticulata Forsskål". PeerJ 10 (18.01.2022): e12821. http://dx.doi.org/10.7717/peerj.12821.
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Background Coastal land development has deteriorated the habitat and water quality for seagrass growth and causes the proliferation of opportunist macroalgae that can potentially affect them physically and biochemically. The present study investigates the morphological and biochemical responses of seagrass from the Hydrocharitaceae family under the macroalgal bloom of Ulva reticulata, induced by land reclamation activities for constructing artificial islands. Methods Five seagrass species, Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Halophila major, and Halophila spinulosa were collected at an Ulva reticulata-colonized site (MA) shoal and a non-Ulva reticulata-colonized site (MC) shoal at Sungai Pulai estuary, Johor, Malaysia. Morphometry of shoots comprising leaf length (LL), leaf width (LW), leaf sheath length (LSL), leaflet length (LTL), leaflet width (LTW), petiole length (PL), space between intra-marginal veins (IV) of leaf, cross vein angle (CVA) of leaf, number of the cross vein (NOC), number of the leaf (NOL) and number of the leaflet (NOLT) were measured on fresh seagrass specimens. Moreover, in-situ water quality and water nutrient content were also recorded. Seagrass extracts in methanol were assessed for total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radical cation scavenging activity (ABTS), and ferric reducing antioxidant power (FRAP). Results Seagrasses in the U. reticulata-colonized site (MA) had significantly higher (t-test, p < 0.05) leaf dimensions compared to those at the non-U. reticulata colonized site (MC). Simple broad-leaved seagrass of H. major and H. ovalis were highly sensitive to the colonization of U. reticulata, which resulted in higher morphometric variation (t-test, p < 0.05) including LL, PL, LW, and IV. Concerning the biochemical properties, all the seagrasses at MA recorded significantly higher (t-test, p < 0.05) TPC, TFC, and ABTS and lower DPPH and FRAP activities compared to those at MC. Hydrocharitaceae seagrass experience positive changes in leaf morphology features and metabolite contents when shaded by U. reticulata. Researching the synergistic effect of anthropogenic nutrient loads on the interaction between seagrasses and macroalgae can provide valuable information to decrease the negative effect of macroalgae blooms on seagrasses in the tropical meadow.
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Tumonggor, Monalisa L. R., Veibe Warouw, Fitje Losung, Inneke F. M. Rumengan, Natalie D. C. Rumampuk i Meiske Salaki. "UJI AKTIVITAS ANTI UV DARI EKSTRAK LAMUN DI PERAIRAN SEKITAR DESA BAHOWO TELUK MANADO KECAMATAN BUNAKEN". JURNAL PESISIR DAN LAUT TROPIS 10, nr 2 (5.06.2022): 226–33. http://dx.doi.org/10.35800/jplt.10.2.2022.54996.
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Seagrass is one of the fertile ecosystems and has enough potential to be exploited. Seagrasses always get exposure of ultra violet (UV) rays so that they produce secondary metabolites to maintain their lives from UV radiation that is harmful to seagrasses. The aims of this study was to identify seagrass samples, obtain the extracts and determine the anti-UV activity test on seagrass extracts. The results of this study obtained 4 types of seagrass from the waters around Bahowo Village, namely Enhalus acoroides, Syringodium isoetifolium, Thalassia hemprichi, and Cymodocea serrulata. These four types of seagrass have been extracted and tested for their anti- UV activity. Seagrass species Enhalus acoroides has anti-UV-A and UV-B activity, Syringodium isoetifolium has anti-UV-B activity, Cymodocea serrulata has anti-UV-C activity and Thalassia hemprichii has anti-UV-A and UV-C activity.
Keywords : Seagrass, Enhalus acoroides, Syringodium isoetifolium Cymodocea serrulata, Thalassia hemprichii, Anti-UV
ABSTRAK
Lamun (seagrass) adalah salah satu ekosistem yang subur dan cukup potensial untuk dapat dimanfaatkan. Lamun selalu mendapatkan paparan sinar ultra violet (UV) sehingga lamun memproduksi metabolit sekunder untuk mempertahankan hidupnya dari radiasi sinar UV yang berbahaya bagi lamun. Tujuan dari penelitian ini yaitu mengidentifikasi sampel lamun, mendapatkan ekstrak dan menentukan uji aktivitas anti-UV pada ekstrak lamun. Hasil penelitian ini didapatkan 4 jenis lamun dari Perairan Sekitar Desa Bahowo yaitu Enhalus acoroides, Syringodium isoetifolium, Thalassia hemprichi, dan Cymodocea serrulata. Dari keempat jenis lamun ini telah diekstraksi dan diuji aktivitas anti-UVnya. Jenis lamun Enhalus acoroides memiliki aktivitas anti-UV- A dan UV-B, Syringodium isoetifolium memiliki aktivitas anti-UV-B, Cymodocea serrulata memiliki aktivitas anti- UV-C dan Thalassia hemprichii memiliki aktivitas anti-UV-A dan UV-C.
Kata kunci: Lamun, Enhalus acoroides, Syringodium isoetifolium Cymodocea serrulata, Thalassia hemprichii, Anti-UV
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Lavery, Paul. "Marine Management: Marine Conservation". Pacific Conservation Biology 5, nr 4 (1999): 240. http://dx.doi.org/10.1071/pc00240a.
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The research papers in this volume highlight some of the major issues in marine conservation and offer some exciting insights into future directions for research and management. It is particularly pleasing that the issue focuses on seagrasses, a component of marine biodiversity that is well recognized and with profound ecological significance, but has suffered widespread decline in its distribution over the past half century. The absence of any accurate inventory of seagrass resources makes it difficult to accurately assess the cumulative impact of human activity on them. However, the need to conserve seagrasses is well recognized and it is exciting to see the significant advances being made in bringing conservation biology techniques to seagrass research. The work of Waycott and Kenworthy (this issue) is clearly showing dramatic differences in the life-history strategies, genetic diversity and population structure of different seagrasses. It suggests that seagrasses are far from the homogenous organism that they seem to have been viewed as up until now. This also supports findings elsewhere which suggest that many of the classic paradigms regarding seagrass biology and ecology are based on inappropriate generalizations from a few species. For example, the work of Paling and others (in this issue) challenges the generally held view that we are unlikely to be able to transplant temperate species of seagrass back into disturbed areas.
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Han, Qiuying, Wenxue Che, Hui Zhao, Jiahui Ye, Wenxuan Zeng, Yufeng Luo, Xinzhu Bai, Muqiu Zhao i Yunfeng Shi. "Effects of Aquaculture and Thalassia testudinum on Sediment Organic Carbon in Xincun Bay, Hainan Island". Water 16, nr 2 (19.01.2024): 338. http://dx.doi.org/10.3390/w16020338.
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Eutrophication due to aquaculture can cause the decline of seagrasses and impact their carbon storage capacity. This study explored the effects of aquaculture on the sediment organic carbon (SOC) in Thalassia testudinum seagrass beds using enzyme activity and microorganisms as indicators. Our results showed that the distance to aquaculture significantly increased the SOC and TN of sediments; the C/N ratio of sediments was reduced by the distance to aquaculture. Distance to aquaculture and seagrasses significantly impacted the δ13C of sediments, and their significant interactive effects on the δ13C of sediments were found. Distance to aquaculture and seagrasses had significantly interactive effects on the cellulase activity of sediments. Distance to aquaculture and seagrasses separately reduced the invertase activity of sediments. SOC in the seagrass bed was significantly positively impacted by cellulase activity and polyphenol oxidase activity in sediments. Firmicutes, Desulfobacterota and Chloroflexi were the dominant taxa in the S1 and S2 locations. From the S1 location to the S2 location, the relative abundances of Firmicutes and Desulfobacterota increased. The functional profiles of COG were relatively similar between the S1 and S2 locations. BugBase phenotype predictions indicated that the microbial phenotypes of all the seagrass sediment samples were dominated by anaerobic bacteria in terms of oxygen utilizing phenotypes. FAPROTAX functional predictions indicated that aquaculture affects functions associated with seagrass bed sediment bacteria, particularly those related to carbon and nitrogen cycling. This study can provide an important basis for understanding the response mechanism of global carbon sink changes to human activities such as aquaculture and supply more scientific data for promoting the conservation and management of seagrass beds.
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Ibrahim, F. H. "Mapping the distribution and occurrence of four newly recorded species of seagrasses in the North-West Arabian Gulf". Mesopotamian Journal of Marine Sciences 33, nr 1 (10.12.2021): 37–48. http://dx.doi.org/10.58629/mjms.v33i1.57.
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For a long time the Iraqi regional waters of north-west Arabian Gulf were classified as free of seagrasses due to the absence of the information concerning these important angiosperms. During the survey carried out by scientist of the Marine Science Center and German divers in 2013-2014 to study the Coral reefs distribution and occurrence in this area, the divers with the help of underwater camera caught photos indicates the existence of seagrass meadows in different places of the north-west Arabian Gulf, so the efforts were made to examine this issue and a work were carried out in April 2017 to study the existence, species composition, occurrences and distribution of seagrass species in the Iraqi marine waters of the north-west Arabian Gulf for the first time. Six sites were chosen distributed along the north-west of Arabian Gulf where the depth was ranging from 0.5 to 15.0 m. Six meadows of seagrass were identified, classified, mapped and seagrass diversity and abundance were investigated. Four species of seagrass namely Halophila stipulacea (Forsskal) Ascherson, Halophila ovalis (R. Brown) Hooker f., Halophila decipiens Ostenfeld and Halodule uninervis (Forsskal) were recorded for the first time in Iraq. Halophila decipiens Ostenfeld was recorded as a new to the whole area of the Arabian Gulf and the Iraqi marine waters and found at a depth of 12-15 m. Halodule uninervis was found to be the most dominant species at all the studied sites followed by Halophila stipulacea. The total seagrass area estimated at all the stations was about 678 hectare fluctuated at different stations. Higher Seagrass total coverage area (240 ha) was found at shallower waters (0.5-3.0 m) compared with 60 ha at deeper waters (12-15 m). The exposed locations showed low seagrass coverage of 35 % comparing with sheltered sites (65 %). The relationship between depth and total coverage of seagrass was significant, while it was not significant with sites. Highest richness value was found in the Alkheran area (Khor Al-Zubair) at a depth of 0.5 m. The relative evenness of the seagrasses species, with different depths showed that the depth 0-3 m has the highest value. The distribution of seagrasses in Khor Al-Zubair and Khor Abdullah down to the open area of Khor Al-Omaya was mapped by using the GIS and Arc Map version 10.5 applications.
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Copertino, Margareth S., Joel C. Creed, Marianna O. Lanari, Karine Magalhães, Kcrishna Barros, Paulo C. Lana, Laura Sordo i Paulo A. Horta. "Seagrass and Submerged Aquatic Vegetation (VAS) Habitats off the Coast of Brazil: state of knowledge, conservation and main threats". Brazilian Journal of Oceanography 64, spe2 (2016): 53–80. http://dx.doi.org/10.1590/s1679-875920161036064sp2.
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Abstract Seagrass meadows are among the most threatened ecosystems on earth, raising concerns about the equilibrium of coastal ecosystems and the sustainability of local fisheries. The present review evaluated the current status of the research on seagrasses and submerged aquatic vegetation (SAV) habitats off the coast of Brazil in terms of plant responses to environmental conditions, changes in distribution and abundance, and the possible role of climate change and variability. Despite an increase in the number of studies, the communication of the results is still relatively limited and is mainly addressed to a national or regional public; thus, South American seagrasses are rarely included or cited in global reviews and models. The scarcity of large-scale and long-term studies allowing the detection of changes in the structure, abundance and composition of seagrass habitats and associated species still hinders the investigation of such communities with respect to the potential effects of climate change. Seagrass meadows and SAV occur all along the Brazilian coast, with species distribution and abundance being strongly influenced by regional oceanography, coastal water masses, river runoff and coastal geomorphology. Based on these geomorphological, hydrological and ecological features, we characterised the distribution of seagrass habitats and abundances within the major coastal compartments. The current conservation status of Brazilian seagrasses and SAV is critical. The unsustainable exploitation and occupation of coastal areas and the multifold anthropogenic footprints left during the last 100 years led to the loss and degradation of shoreline habitats potentially suitable for seagrass occupation. Knowledge of the prevailing patterns and processes governing seagrass structure and functioning along the Brazilian coast is necessary for the global discussion on climate change. Our review is a first and much-needed step toward a more integrated and inclusive approach to understanding the diversity of coastal plant formations along the Southwestern Atlantic coast as well as a regional alert the projected or predicted effects of global changes on the goods and services provided by regional seagrasses and SAV.
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Az zahra, Firda, Chairul Chairul i Indra Junaidi Zakaria. "Carbon Stock Of Seagrass In Karang Tirta’s Coastal Area, Padang". Bioscience 4, nr 1 (31.03.2020): 73. http://dx.doi.org/10.24036/0202041108201-0-00.
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The seagrass beds are the spawning, nursery, and the feeding ground for some oceanic biota. It’s also can trapped the sediment and stabilized the substrate so the waters looks clear. Beside those abilities, seagrasses are also can store the carbon. The research was conducted in karang tirta’s coastal area, padang city to analyze the carbon stock of seagrass that stored within their biomass. The biomass was analyzed by harvesting the seagrass at transect 25x25cm, while the carbon stock was analyzed by using walkley & black method. Seagrass beds in karang tirta’s coastal has 14,1 ha (142.546,36 m2) distribution area and it’s stored 18,05 tons of carbon. based on these result the seagrass beds in karang tirta’s coastal area has stored 1,2 tons C/ha. the highest carbon stock has found in the below ground, especially in their rhizomes.
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Ruiz-Diaz, Claudia Patricia, Carlos Toledo-Hernández, Juan Luis Sánchez-González i Alex E. Mercado-Molina. "A successful method to restore seagrass habitats in coastal areas affected by consecutive natural events". PeerJ 11 (2.01.2024): e16700. http://dx.doi.org/10.7717/peerj.16700.
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Background Seagrass meadows, known for providing essential ecosystem services like supporting fishing, coastline protection from erosion, and acting as carbon sinks to mitigate climate change effects, are facing severe degradation. The current deteriorating state can be attributed to the combination of anthropogenic activities, biological factors (i.e., invasive species), and natural forces (i.e., hurricanes). Indeed, the global seagrass cover is diminishing at an alarming mean rate of 7% annually, jeopardizing the health of these vital ecosystems. However, in the Island Municipality of Culebra, Puerto Rico, losses are occurring at a faster pace. For instance, hurricanes have caused over 10% of cover seagrass losses, and the natural recovery of seagrasses across Culebra’s coast has been slow due to the low growth rates of native seagrasses (Thalassia testudinum and Syringodium filiforme) and the invasion of the invasive species Halophila stipulacea. Restoration programs are, thus, necessary to revitalize the native seagrass communities and associated fauna while limiting the spread of the invasive species. Methods Here, we present the results of a seagrass meadow restoration project carried out in Punta Melones (PTM), Culebra, Puerto Rico, in response to the impact of Hurricanes Irma and María during 2017. The restoration technique used was planting propagation units (PUs), each with an area of 900 cm2 of native seagrasses Thalassia testudinum and Syringodium filiforme, planted at a depth between 3.5 and 4.5 m. A total of 688 PUs were planted between August 2021 and August 2023, and a sub-sample of 88 PUs was monitored between August 2021 and April 2023. Results PUs showed over 95% of the seagrass survived, with Hurricane Fiona causing most of the mortalities potentially due to PUs burial by sediment movement and uplifting by wave energy. The surface area of the planting units increased by approximately 200% (i.e., 2,459 cm2), while seagrass shoot density increased by 168% (i.e., 126 shoots by PU). Additionally, flowering and fruiting were observed in multiple planting units, indicating 1) that the action taken did not adversely affect the PUs units and 2) that the project was successful in revitalizing seagrass populations. The seagrass restoration project achieved remarkable success, primarily attributed to the substantial volume of each PUs. Likely this high volume played a crucial role in facilitating the connection among roots, shoots, and microfauna while providing a higher number of undamaged and active rhizome meristems and short shoots. These factors collectively contributed to the enhanced growth and survivorship of the PUs, ultimately leading to the favorable outcome observed in the seagrass restoration project.
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Wyllie-Echeverria, S., P. Arzel i P. A. Cox. "Seagrass conservation: lessons from ethnobotany". Pacific Conservation Biology 5, nr 4 (1999): 329. http://dx.doi.org/10.1071/pc000329.
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Current measures to protect and conserve seagrasses are nested in the legislative or judicial process. While this legal/judicial model may arrest activity in the short term, we contend that it may not deliver a long-term solution. We propose an alternative model, using insights derived from historical archives and participant observation interviews. People tend to conserve what they cherish and use. With the seagrass biome disappearing around the globe, we suggest one strategy for seagrass conservation lies in historical and ethnobotanical records of seagrass use.