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1
ERNAWATI, Ni Made, and Made Ayu Pratiwi. "STRUKTUR KOMUNITAS EKOSISEM PADANG LAMUN PADA DAERAH INTERTIDAL DI PANTAI SANUR, BALI." ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) 12, no. 1 (May 31, 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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Batuwael, Anggi Wawan, and Dominggus Rumahlatu. "ASOSIASI GASTROPODA DENGAN TUMBUHAN LAMUN DI PERAIRAN PANTAI NEGERI TIOUW KECAMATAN SAPARUA KABUPATEN MALUKU TENGAH." Biopendix: Jurnal Biologi, Pendidikan dan Terapan 4, no. 2 (May 22, 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., and Sandy Wyllie-Echeverria. "Natural and human-induced disturbance of seagrasses." Environmental Conservation 23, no. 1 (March 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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Ierodiaconou, Daniel A., and 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, no. 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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J. Lee Long, W., R. G. Coles, and L. J. McKenzie. "Issues for seagrass conservation management in Queensland." Pacific Conservation Biology 5, no. 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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Omollo, Derrick, Virginia Wang’ondu, Michael Githaiga, Daniel Gorman, and James Kairo. "The Contribution of Subtidal Seagrass Meadows to the Total Carbon Stocks of Gazi Bay, Kenya." Diversity 14, no. 8 (August 11, 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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Ahmad-Kamil, E. I., R. Ramli, S. A. Jaaman, J. Bali, and 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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Burkholder, Derek A., Michael R. Heithaus, and James W. Fourqurean. "Feeding preferences of herbivores in a relatively pristine subtropical seagrass ecosystem." Marine and Freshwater Research 63, no. 11 (2012): 1051. http://dx.doi.org/10.1071/mf12029.
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Understanding forage choice of herbivores is important for predicting the potential impacts of changes in their abundance. Such studies, however, are rare in ecosystems with intact populations of both megagrazers (sirenians, sea turtles) and fish grazers. We used feeding assays and nutrient analyses of seagrasses to determine whether forage choice of grazers in Shark Bay, Australia, are influenced by the quality of seagrasses. We found significant interspecific variation in removal rates of seagrasses across three habitats (shallow seagrass bank interior, shallow seagrass bank edge, deep), but we did not detect variation in gazing intensity among habitats. In general, grazers were more likely to consume fast-growing species with lower carbon : nitrogen (C : N) and carbon : phosphorus (C : P) ratios, than the slower-growing species that are dominant in the bay. Grazer choices were not, however, correlated with nutrient content within the tropical seagrasses. Slow-growing temperate seagrasses that experienced lower herbivory provide greater habitat value as a refuge for fishes and may facilitate fish grazing on tropical species. Further studies are needed, however, to more fully resolve the factors influencing grazer foraging preferences and the possibility that grazers mediate indirect interactions among seagrass species.
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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, and Permana Yudiarso. "Association Analysis of Seagrass Coverage and Human Activities in Nusa Lembongan." Jurnal Biodjati 7, no. 2 (November 30, 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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Zabarte-Maeztu, Iñigo, Fleur E. Matheson, Merilyn Manley-Harris, Robert J. Davies-Colley, Megan Oliver, and 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, no. 9 (August 21, 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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Lavery, Paul. "Marine Management: Marine Conservation." Pacific Conservation Biology 5, no. 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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Ramesh, Chatragadda, and Raju Mohanraju. "Seagrass Ecosystems of Andaman and Nicobar Islands: Status and Future Perspective." Environmental and Earth Sciences Research Journal 7, no. 4 (December 31, 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, and Otadoy Julie B. "Seagrass Diversity and Distribution in Maribojoc Bay, Bohol, Philippines." American Journal of Environment and Climate 1, no. 1 (May 3, 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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Jones, Cynthia M. "Can we predict the future: juvenile finfish and their seagrass nurseries in the Chesapeake Bay." ICES Journal of Marine Science 71, no. 3 (September 4, 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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Sidi Cheikh, Mohamed Ahmed, Salomão Bandeira, Seydouba Soumah, Gnilane Diouf, Elisabeth Mayé Diouf, Omar Sanneh, Noelo Cardoso, et al. "Seagrasses of West Africa: New Discoveries, Distribution Limits and Prospects for Management." Diversity 15, no. 1 (December 21, 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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Bongga, Marthen, Calvyn F. A. Sondak, Deisle RH Kumampung, Kakaskasen A. Roeroe, Sandra Olivia Tilaar, and Joudy Sangari. "KAJIAN KONDISI KESEHATAN PADANG LAMUN DI PERAIRAN MOKUPA KECAMATAN TOMBARIRI KABUPATEN MINAHASA." JURNAL PESISIR DAN LAUT TROPIS 9, no. 3 (October 4, 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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Pollard, PC, and M. Greenway. "Photosynthetic characteristics of seagrasses (Cymodocea serrulata, Thalassia hemprichii and Zostera capricornia) in a low-light environment, with a comparison of leaf-marking and lacunal-gas measurements of productivity." Marine and Freshwater Research 44, no. 1 (1993): 127. http://dx.doi.org/10.1071/mf9930127.
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We describe the photosynthetic characteristics of three seagrasses and the relationship between their production and natural light intensities (photosynthesis-irradiance response, i.e. PI curves). Seagrass production (gross production minus shoot respiration) was measured in the field by the rate of gas release from the lacuna1 space of whole seagrass shoots and compared with net leaf production. Field work was carried out on the seagrasses Cymodocea serrulata (R. Br.) Aschers, and Magnus, Thalassia hemprichii (Ehrenb.) Aschers., and Zostera capricornia Aschers. in the turbid, warm waters of Cairns Harbour, Queensland, Australia. The photosynthetic efficiencies (the initial slope of the PI curves) of all of the seagrass species were 10 times greater than any previously measured for the same species in higher-light environments. The high compensating light intensities (80-92 �E m-2 s-1) showed that the plants have high respiration rates that were probably due to the high water temperatures (29-33�C) of the harbour. The seagrasses responded to small increases of light at low light intensities by rapidly reaching saturating light intensities, and the maximum rates of production were between 0.4 and 0.6 mg C h-1 shoot-1. The average period of exposure to saturating light intensity was 2 h day-1. One-quarter of the gross production was lost to plant respiration. The net productivity and respiration of all three seagrasses was calculated from this photoperiod. Net leaf production in situ compared well with the seagrass production estimates that were measured with the lacunal-gas technique. Most of the production appeared to be allocated to the above-ground tissue, a feature consistent with seagrasses growing in low-light and terrigenous sediments.
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Hirst, A. J., K. Giri, D. Ball, and R. S. Lee. "Determination of the physical drivers of Zostera seagrass distribution using a spatial autoregressive lag model." Marine and Freshwater Research 68, no. 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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Fraser, Matthew W., Gary A. Kendrick, Pauline F. Grierson, James W. Fourqurean, Mathew A. Vanderklift, and Diana I. Walker. "Nutrient status of seagrasses cannot be inferred from system-scale distribution of phosphorus in Shark Bay, Western Australia." Marine and Freshwater Research 63, no. 11 (2012): 1015. http://dx.doi.org/10.1071/mf12026.
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Differences in phosphorus (P) availability can influence the ecology and physiology of seagrass communities; and are usually inferred from changes in the relative P content in seagrass leaves. Shark Bay is a subtropical marine embayment, with decreasing P concentrations in the water column and sediments from north to south across the entire embayment. We examined the P and nitrogen (N) content of seagrass leaves and P content of sediments across the Faure Sill and Wooramel delta region of Shark Bay, to determine whether the leaf content of seagrasses in Shark Bay also decreased from north to south over smaller spatial scales. Nutrient content of Amphibolis antarctica and Halodule uninervis were highly variable and were not strongly correlated with sediment P concentrations. Mean N : P ratios of seagrasses (<33.5) were not indicative of P limitation, as has been previously assumed for Shark Bay. We conclude that availability of P for uptake by seagrasses across Shark Bay may be highly localised and cannot be predicted from system-scale gradients (>100 km) of sedimentary P distributions. We suggest that P availability to seagrasses is more likely a complex function of differing nutrient inputs, rates of delivery to the plants and cycling rates.
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van Wyk, Johanna W., Janine B. Adams, and Sophie von der Heyden. "Conservation implications of herbicides on seagrasses: sublethal glyphosate exposure decreases fitness in the endangered Zostera capensis." PeerJ 10 (November 15, 2022): e14295. http://dx.doi.org/10.7717/peerj.14295.
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Worldwide seagrass populations are in decline, calling for urgent measures in their conservation. Glyphosate is the most widely used herbicide globally, leading to increasing concern about its ecological impact, yet little is known about the prevalence or impact of glyphosate on seagrasses. In this study, we investigated the effect of sublethal glyphosate exposure on the endangered seagrass, Zostera capensis, to identify effects on growth, photosynthetic pigments and leaf morphology as measures of seagrass fitness. Seagrasses were exposed to a single dose of a commercial glyphosate formulation—ranging between 250 to 2,200 µg/L. After three weeks, the median leaf area decreased by up to 27%, with reductions of up to 31% in above ground biomass (p < 0.05). Photosynthetic pigment concentration showed no significant difference between groups. The observed effects on biomass and leaf area were seen at glyphosate levels below the regulatory limits set for surface water by several countries and may negatively affect the long-term resilience of this ecosystem engineer to additional stressors, such as those associated with climate change and anthropogenic pollution. As such, glyphosates and other herbicides that are washed into estuarine and marine ecosystems, pose a significant threat to the persistence of seagrasses and are important factors to consider in seagrass conservation, management and restoration efforts.
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Copertino, Margareth S., Joel C. Creed, Marianna O. Lanari, Karine Magalhães, Kcrishna Barros, Paulo C. Lana, Laura Sordo, and 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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Leemans, Luuk, Isis Martínez, Tjisse van der Heide, Marieke M. van Katwijk, and Brigitta I. van Tussenbroek. "A Mutualism Between Unattached Coralline Algae and Seagrasses Prevents Overgrazing by Sea Turtles." Ecosystems 23, no. 8 (February 18, 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, and Japar Sidik Bujang. "Morphological and biochemical responses of tropical seagrasses (Family: Hydrocharitaceae) under colonization of the macroalgae Ulva reticulata Forsskål." PeerJ 10 (January 18, 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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Namoua, Dilivia J., Adnan S. Wantasen, Khristin I. F. Kondoy, Rene Ch Kepel, Febry S. I. Menajang, and Wilmy Pelle. "Carbon Absorption in Seagrasses in Tongkaina Coastal Waters, Bunaken District, Manado City, North Sulawesi." Jurnal Ilmiah PLATAX 10, no. 2 (September 30, 2022): 433. http://dx.doi.org/10.35800/jip.v10i2.43485.
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This study was conducted to determine the types of seagrasses and calculate biomass and calculate how much carbon absorption in seagrasses was found in the location of Tongkaina Beach, Bunaken District, Manado City, North Sulawesi. The sampling procedure in the field is the method of cruising surveys. A cruising survey is a sample collection method that is carried out by walking through the coastal area of all seagrasses found. After the sampling at the site is completed, the sample in the inventory is then photographed. The samples that have been obtained are analyzed in the laboratory using the loss on ignition (LOI) method. The results of the study on Tongkaina coastal waters covering an area of 25,000 meters with a coastal length of ±500 meters, in an area parallel to the coastline as wide as ±50 meters towards the sea and six types of seagrasses were obtained, namely: Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium, Cymodocea rotundata, Halodule uninervis, and Halodule pinifolia. The biomass in seagrasses found had an average value of 78.10% with the highest individual seagrass biomass found in seagrass type Enhalus acoroides with a biomass value of 87.23grams of dry weight (gbk)/individual and the lowest type of seagrass individual biomass value was found in seagrass type seagrass with a biomass value of 66.67grams of dry weight (gbk)/individual. The total carbon content calculated in the entire seagrass obtained was 46,0941gCKeywords: Tongkaina Beach; seagrasses; biomass; carbon absorptionAbstrakPenelitian ini dilakukan untuk mengetahui jenis-jenis lamun dan menghitung biomassa serta menghitung berapa serapan karbon pada lamun yang ditemukan dilokasi Perairan Pantai Tongkaina Kecamatan Bunaken Kota Manado Provinsi Sulawesi Utara. Prosedur pengambilan sampel di lapangan menggunakan metode survei jelajah. Survei jelajah adalah metode pengumpulan sampel yang di lakukan dengan cara menyusuri daerah pantai terhadap semua lamun yang ditemukan. Setelah pengambilan sampel di lokasi selesai, sampel di inventarisir kemudian difoto. Sampel yang telah diperoleh dianalisa di laboratorium dengan menggunakann metode loss on ignition (LOI). Hasil penelitian pada perairan pantai Tongkaina seluas 25.000 meter dengan panjang pantai ±500 meter sejajar garis pantai dan lebar ±50 meter ke arah laut. Ditemukan enam jenis lamun yaitu: Enhalus acoroides, Thalassia hemprichii, Syringodium isoetifolium, Cymodocea rotundata, Halodule uninervis dan Halodule pinifolia. Biomassa pada lamun yang ditemukan memiliki nilai rata-rata 78,53% dengan biomassa individu lamun tertinggi terdapat pada lamun jenis Enhalus acoroides dengan nilai biomassa mencapai 87,23gram berat kering (gbk)/individu dan nilai biomassa individu jenis lamun terendah terdapat pada lamun jenis Syringodium isoetifolium dengan nilai biomassa 66,67gram berat kering (gbk)/individu. Untuk total kandungan karbon yang dihitung pada keseluruhan lamun yang didapat sebesar 46,0941gC.Kata kunci: Pantai Tongkaina; Lamun; biomasa, serapan carbon
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Coles, RG, WJ Lee Long, RA Watson, and KJ Derbyshire. "Distribution of seagrasses, and their fish and penaeid prawn communities, in Cairns harbour, a tropical estuary, Northern Queensland, Australia." Marine and Freshwater Research 44, no. 1 (1993): 193. http://dx.doi.org/10.1071/mf9930193.
Full textAbstract:
From aerial photography (July 1987) and diving surveys (February 1988), 876 ha of seagrasses (eight species) were mapped in Cairns Harbour, tropical north-eastern Queensland. Zostera capricorni was the most common seagrass species and had the greatest biomass at 79 g m-2 dry weight of stems and leaves and 180 g m-2 dry weight of roots and rhizomes. The maximum shoot density found was 4798 shoots m-2 of Halodule pinifolia, the second most common species. Seagrasses were found only between 0.5 and 5.0 m below mean sea level. Zostera capricorni was found at the shallowest depths, Halodule pinifolia at the deepest depths. Twenty species of penaeid prawns, nine of which are marketed commercially, were sampled from the seagrass beds. Abundances of prawns of commercial species were significantly greater on seagrass-covered substrata than on nonvegetated substrata. Overall, 5614 mostly small or juvenile fish, representing 134 taxa, were sampled from seagrasses in Cairns Harbour. The most numerous fish species were a goby, Yongeichthys criniger, and a pony fish, Leiognathus splendens. Only 15 species were highly valued as recreational fish, and only 11 species were highly valued as commercial fish. Of the fish species, five (4%) were highly valued species of both groups. The density of fish on the seagrass beds was estimated to be 8809 fish ha-1.
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Lanuru, Mahatma, Rohani Ambo-Rappe, Khairul Amri, and Susan L. Williams. "Hydrodynamics in Indo-Pacific seagrasses with a focus on short canopies." Botanica Marina 61, no. 1 (January 26, 2018): 1–8. http://dx.doi.org/10.1515/bot-2017-0037.
Full textAbstract:
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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Reid, T. "Seagrass in Australia. A Strategic Review and Development of a Research and Development Plan." Pacific Conservation Biology 6, no. 2 (2000): 178. http://dx.doi.org/10.1071/pc00178a.
Full textAbstract:
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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Luong, Cao Van, Nguyen Manh Linh, Vu Manh Hung, Dam Duc Tien, Dau Van Thao, and Tran Dinh Lan. "The status of seagrass communities in the Truong Sa archipelago." Tạp chí Khoa học và Công nghệ biển 20, no. 3 (October 1, 2020): 285–95. http://dx.doi.org/10.15625/1859-3097/20/3/15076.
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Seagrasses in Truong Sa archipelago have not been intensively studied and understood, even in some obviously progressive works recently published. It is essential to carry out much more researches to fill up understanding gaps of seagrasses in the area. In 2019, within the framework of the project coded KC09.29/16–20, two surveys were conducted for three selected islands (Truong Sa Lon, Thuyen Chai and Song Tu Tay) in the area, focusing on marine ecosystems including seagrass beds. Survey results in the selected islands show eight seagrass species (one new record), the estimated total distribution area of 1,190 ha, the total reserve of biomass reaching 7,417.2 tons.dry, equivalent to 11,432.8 tons.CO2.
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Hwang, Charnsmorn, Chih-Hua Chang, Michael Burch, Milena Fernandes, and Tim Kildea. "Effects of Epiphytes and Depth on Seagrass Spectral Profiles: Case Study of Gulf St. Vincent, South Australia." International Journal of Environmental Research and Public Health 16, no. 15 (July 29, 2019): 2701. http://dx.doi.org/10.3390/ijerph16152701.
Full textAbstract:
Seagrasses are a crucial indicator species of coastal marine ecosystems that provide substratum, shelter, and food for epiphytic algae, invertebrates, and fishes. More accurate mapping of seagrasses is essential for their survival as a long-lasting natural resource. Before reflectance spectra could properly be used as remote sensing endmembers, factors that may obscure the detection of reflectance signals must be assessed. The objectives in this study are to determine the influence of (1) epiphytes, (2) water depth, and (3) seagrass genus on the detection of reflectance spectral signals. The results show that epiphytes significantly dampen bottom-type reflectance throughout most of the visible light spectrum, excluding 670–679 nm; the depth does influence reflectance, with the detection of deeper seagrasses being easier, and as the depth increases, only Heterozostera increase in the exact “red edge” wavelength at which there is a rapid change in the near-infrared (NIR) spectrum. These findings helped improve the detection of seagrass endmembers during remote sensing, thereby helping protect the natural resource of seagrasses.
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Rein, Thu. "Seagrass surveys in Shwe Thaung Yan coastal areas, the southern part of Rakhine Coastal Region, Myanmar: biodiversity, coverage and biomass." Journal of Aquaculture & Marine Biology 8, no. 3 (2019): 105–12. http://dx.doi.org/10.15406/jamb.2019.08.00248.
Full textAbstract:
Studies on percent cover and biomass of seagrasses from Shwe Thaung Yan coastal areas (Inn Din Gyi, Kyauk Nagar and Phoe Htaung Gyaing), the Southern parts of Rakhine Coastal Region, were carried out between March and August, 2018. A total of 8 species of seagrasses, namely Syringodiumisoetifolium (Ascherson) Danty, Halodulepinifolia (Miki) den Hartog, Haloduleuninervis (Forsskal) Ascherson, Cymodocearotundata Ehrenberg et Hemprich ex Ascherson, C. serrulata (R. Brown) Ascherson et Magnus, Thalassiahemprichii(Ehrenberg) Ascherson, Halophila major (Zoll.) Miquel and Enhalusacoroides (Linnaeus f.) Royle, were recorded in three study sites. Seagrass meadow in this study showed seasonal variations in both percent cover and biomass. Total seagrass coverage and biomass were higher in the dry season than in the monsoon season. Total seagrass coverage ranged between 8% and 75% in Phoe Htaung Gyaing, between 10% and 42% in Kyauk Nagar, and between 15% and 43% in Inn Din Gyi. Total seagrass mean biomass was 50.2413-259.846gdry.wtm-2 in Phoe Htaung Gyaing, 63.0194 -321.535gdry.wtm-2 in Kyauk Nagar, and 98.6819-416.237gdry.wtm-2 in Inn Din Gyi.
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Nguyen Xuan, Hoa, Nhu Thuy Nguyen Nhat, and 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, no. 2 (June 30, 2021): 183–89. http://dx.doi.org/10.15625/1859-3097/16405.
Full textAbstract:
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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Farid, M. A., S. Rasidi, and M. P. Patria. "THE COMMUNITY STRUCTURE OF SEAGRASS IN ENGGANO ISLANDS, BENGKULU." Marine Research in Indonesia 33, no. 1 (June 30, 2008): 7–10. http://dx.doi.org/10.14203/mri.v33i1.501.
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The community structure of seagrass in Enggano Islands has been studied in August 2004. The aim of the study was to assess the seagrass community including species composition, density, and distribution pattern. The study was executed using transect quadrat methods, where seagrasses were counted in quadrats of 50 cm2. The result showed that the Enggano Islands seagrasses consist of seven species Enhalus acoroides, Halophila ovalis, Thallasia hemprichii, Cymodocea rotundata, Cymodocea serrulata, Halodule uninervis, and Syringodium isoetifolium. The highest density occurred in Dua Island dominated by Thallasia hemprichii (363.3 shoots m-2), while the lowest density occurred in Merbau Island dominated by Enhalus acoroides (0.4 shoot m-2). The highest diversity index (HB) occurred in Kiape Bay (1.446) and the lowest in Merbau Island (0.634). In general, seagrass community in Enggano Islands was dominated by Thallasia hemprichii. All species has clumped distribution pattern (Id > 1).
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Vanderklift, MA, RD Pillans, M. Hutton, L. De Wever, GA Kendrick, A. Zavala-Perez, A. Vergés, et al. "High rates of herbivory in remote northwest Australian seagrass meadows by rabbitfish and green turtles." Marine Ecology Progress Series 665 (April 29, 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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Atmaja, Putu Satya Pratama, Dietriech G. Bengen, and 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, no. 2 (June 29, 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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Uku, J., L. Daudi, V. Alati, A. Nzioka, and C. Muthama. "The status of seagrass beds in the coastal county of Lamu, Kenya." Aquatic Ecosystem Health & Management 24, no. 1 (January 2, 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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Naufal, Mohammed, and Gadi Padmavati. "Ethnobotany of three sea grass species from Port Blair, a step towards its conservation in Andaman Islands." Journal of Tropical Life Science 11, no. 1 (February 3, 2021): 11–16. http://dx.doi.org/10.11594/jtls.11.01.02.
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Ethno-phycology is the study of the relationships of human society to flora and its ecosystem. In the marine world, ethno-biology is a thriving area of research which have yielded valuable ethno-biological knowledge. The main goal of the present study was to understand the effect of abiotic factors as well as the natural and anthropogenic disturbances that shape seagrass community in Andaman Island and to reveal the knowledge of the local people, about the significance of seagrass habitat and its conservation. The qualitative study on distribution of seagrasses in Chidiyatapu (11° 29' 30" to 11° 30' 34" N and 92° 35' 10" to 92° 42' 30" E) was carried out during December2012 to February 2013. A total of three seagrass species such as Thalassia hempirichi (Ehrenberg) Ascherson, 1871, Halodule uninervis (R.Brown) J.D.Hooker 1858, Halophila ovalis (Forsskål) Ascherson 1882, where identified. Among them, T. hempirichi, and H. ovalis found in this study was reported to have the ethno-medicinal value from west coast of India. As a part of the study, the semi-structured survey was carried out among the local coastal people to analyse the Traditional Ecological Knowledge (TEK). The survey has revealed the unawareness of coastal residents about the medicinal, nutritional as well as conservational values of seagrasses. An effective implementation has to be taken to make them aware that seagrasses are fundamental components of healthy marine ecosystems and the local livelihoods that rely on them. The present findings provide the first report on the ethno-phycology of seagrasses from South Andaman Island.
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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, no. 1 (December 10, 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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Wyllie-Echeverria, S., P. Arzel, and P. A. Cox. "Seagrass conservation: lessons from ethnobotany." Pacific Conservation Biology 5, no. 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.
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Mukai, H. "Biogeography of the tropical seagrasses in the western Pacific." Marine and Freshwater Research 44, no. 1 (1993): 1. http://dx.doi.org/10.1071/mf9930001.
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Seagrass species and their distributions were recorded from 18 localities in the tropical and subtropical Pacific. These field observations were collated with a review of the recent literature, enabling the present distribution patterns of seagrass species in the western Pacific to be described and the origin of those species to be discussed in relation to the major oceanic currents of the region. The major tropical seagrasses of the western Pacific are Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, C. serrulata, Halodule uninervis, Syringodium isoetifolium and Thalassodendron ciliatum, with T. hemprichii and E. acoroides being the two most widely distributed species. Species are found in coastal waters along the Equatorial Countercurrent and the Kuroshio and East Australian Currents. The highest number of seagrass species occurs in the coastal waters of Malesia enclosed by Indonesia, Borneo, Papua New Guinea and the Torres Strait (northern Australia). This area is considered to be the source of all of the seagrass species of the western Pacific, i.e. the centre of their origin. A relationship between the distance from this centre of origin along the above three major ocean currents and the diversity of seagrass species was found: the further from the origin, the poorer the seagrass diversity. These observations support the centre-of-origin theory that was first proposed by den Hartog to describe the processes responsible for the present distribution patterns of seagrasses in the western Pacific.
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Jason G. Tuang-tuang. "Thriving Seagrasses in Rocky Sandy Substrate in Tinabilan, Northwest Leyte, Philippines." East Asian Journal of Multidisciplinary Research 1, no. 9 (October 29, 2022): 1881–86. http://dx.doi.org/10.55927/eajmr.v1i9.1258.
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The coastline of Palompon, Leyte has endowed with rich seagrass abundance and diversity which supports the well-established Siganid industry. Baseline information on the cover and species composition were gathered using the transect-quadrat method. Results showed that there were four (4) species of seagrasses identified in the coastal area of Tinabilan, Palompon, Leyte. Cymodocea rotundata and Thalassia hemprichii were observed in all the sampling stations. The average percentage cover of seagrasses was 8.36% which revealed in poor condition. However, the poor percentage cover condition can be associated with the topography and environmental factors in the area which is observed to have been dominated with rocky-sandy substrate and high temperature which possibly affects negatively the biological processes of the seagrass species.
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Nomme, Kathy M., and Paul G. Harrison. "Evidence for interaction between the seagrasses Zostera marina and Zostera japonica on the Pacific coast of Canada." Canadian Journal of Botany 69, no. 9 (September 1, 1991): 2004–10. http://dx.doi.org/10.1139/b91-252.
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Experiments were undertaken to differentiate between abiotic and biotic factors affecting seagrass growth. Monospecific patches of both Zostera marina and Zostera japonica were transplanted into one shallow subtidal and three intertidal sites at Roberts Bank, British Columbia. In transplanted patches, initiated in 1988, neither Z. marina nor Z. japonica showed any consistent differences in either population growth or mean shoot length among the sites. Abiotic environmental conditions could therefore not be considered responsible for the differences observed between the natural vegetation of the respective monospecific zones and the zone of naturally mixed seagrass vegetation. In a manipulation experiment, opaque and clear plastic seagrass canopies were imposed on Z. japonica vegetation and the resulting growth was compared with treatments of a natural Z. marina canopy and removal of the natural canopy. The artificial seagrasses combined with the patch layout of the experiment did not create the shade conditions intended and may have facilitated the loss of shoots. The results were not conclusive, but there were consistently higher densities of Z. japonica in the treatment where Z. marina had been removed. Interactions between these two seagrasses in their vegetative phase may contribute to the observed differences in population and morphological characters, but the dispersal and establishment phases remain to be studied. Key words: Zostera marina, Zostera japonica, seagrass, competition, transplants, artificial seagrass.
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Lee Long, WJ, JE Mellors, and RG Coles. "Seagrasses between Cape York and Hervey Bay, Queensland, Australia." Marine and Freshwater Research 44, no. 1 (1993): 19. http://dx.doi.org/10.1071/mf9930019.
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The area of seagrasses in waters adjacent to the Queensland coast between Cape York and Hervey Bay is approximately 4000 km2. Seagrasses were found near estuaries, in coastal bays and associated with islands, at sites that provided shelter from the south-easterly trade winds and Pacific Ocean swells. Of the seagrass meadows mapped, 37% had a bottom vegetation cover greater than 50%. Two large continuous areas (total of approximately 2500 km2) of seagrass of predominantly Halophila species were found in deep water in Hervey Bay and between Barrow Point and Lookout Point and may be part of a much larger area of deep-water seagrass habitat not yet surveyed in the Great Barrier Reef province. Fourteen seagrass species were found in the surveyed region, and most were typical of the northern Australian and Indo-West Pacific region. The opportunistic Halophila and Halodule species were most common, with Halophila ovalis (R. Br.) Hook. f. and Halodule uninervis (Forsk.) Aschers. each being found in more than 15% of samples. High species richness occurred at depths of less than 6 m, predominantly in sheltered bays at coastal and island locations. Low species richness at estuary- associated sites may be due to stresses caused by low salinity during monsoonal runoff periods or exposure at low tides. Zostera capricorni Aschers. was restricted to these areas and may have a competitive advantage over other species with lesser tolerance to varying salinity. Species richness decreased with an increase in both latitude and depth. The latitudinal limits of recorded distributions for some of these tropical seagrasses were confirmed. Seagrass biomass decreased with increasing depth, but parameters of seagrass abundance showed no correlation with latitude, being dependent on a complex of site-related factors. High seagrass biomass occurred at sheltered sites, including estuary-associated, coastal-bay and island-associated sites. The maximum recorded above-ground biomass was 102.9 g m-2 for Zostera capricorni at Upstart Bay. Shoot densities reached 13 806 shoots m-2 for Halophila ovalis at Escape River, and the highest leaf area index was 1.81 for Zostera capricorni at Upstart Bay.
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York, Paul H., Peter I. Macreadie, and Michael A. Rasheed. "Blue Carbon stocks of Great Barrier Reef deep-water seagrasses." Biology Letters 14, no. 12 (December 2018): 20180529. http://dx.doi.org/10.1098/rsbl.2018.0529.
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Shallow-water seagrasses capture and store globally significant quantities of organic carbon (OC), often referred to as ‘Blue Carbon’; however, data are lacking on the importance of deep-water (greater than 15 m) seagrasses as Blue Carbon sinks. We compared OC stocks from deep-, mid- and shallow-water seagrasses at Lizard Island within the Great Barrier Reef (GBR) lagoon. We found deep-water seagrass ( Halophila species) contained similar levels of OC to shallow-water species (e.g. Halodule uninervis ) (0.64 ± 0.08% and 0.9 ± 0.1 mg C cm −3 , 0.87 ± 0.19% and 1.3 ± 0.3 mg C cm −3 , respectively), despite being much sparser and smaller in stature. Deep-water seagrass sediments contained significantly higher levels (approx. ninefold) of OC than surrounding bare areas. Inorganic carbon (CaCO 3 ) levels were relatively high in deep-water seagrass sediments (8.2 ± 0.4%) and, if precipitated from epiphytes within the meadow, could offset the potential CO 2 -sink capacity of these meadows. The δ 13 C signatures of sediment samples varied among depths and habitats (−10.9 and −17.0), reflecting contributions from autochthonous and allochthonous sources. If the OC stocks reported in this study are similar to deep-water Halophila meadows elsewhere within the GBR lagoon (total area 31 000 km 2 ), then OC bound within this system is roughly estimated at 27.4 million tonnes.
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Rosalina, Dwi, Endang Yuli Herawati, Yenny Risjani, and Muhammad Musa. "KEANEKARAGAMAN SPESIES LAMUN DI KABUPATEN BANGKA SELATAN PROVINSI KEPULAUAN BANGKA BELITUNG." EnviroScienteae 14, no. 1 (April 28, 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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Tahapary, Rian, Hasan Tuaputty, Sintje Liline, Tri Santi Kurnia, and Muhammad Tarmizi Kubangun. "Keanekaragaman Jenis dan Kepadatan Ikan di Padang Lamun Pantai Desa Akoon Kecamatan Nusalaut Kabupaten Maluku Tengah." bionature 20, no. 2 (December 8, 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, and Noorsalam R. Nganro. "DISTRIBUTION OF SEAGRASSES IN INNER AMBON BAY." Jurnal Ilmu dan Teknologi Kelautan Tropis 8, no. 1 (November 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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Dilipan, Elangovan, Jutta Papenbrock, and Thirunavakkarasu Thangaradjou. "Random amplified polymorphic DNA (RAPD) finger prints evidencing high genetic variability among marine angiosperms of India." Journal of the Marine Biological Association of the United Kingdom 97, no. 6 (May 19, 2016): 1307–15. http://dx.doi.org/10.1017/s0025315416000631.
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In India 14 seagrass species can be found with monospecific genera (Enhalus, ThalassiaandSyringodium),Cymodoceawith two species andHalophilaandHalodulerepresented by more than two taxonomically complex species. Considering this, the present study was made to understand the level and pattern of genetic variability among these species collected from Tamilnadu coast, India. Random amplified polymorphic DNA (RAPD) analysis was used to evaluate the level of polymorphism existing between the species. Out of the 12 primers tested, 10 primers amplified 415 DNA fragments with an average of 41.5 fragments per primer. Of the total 415 amplified fragments only 123 (29.7%) were monomorphic and the remaining 292 (70.3%) were polymorphic for Indian seagrass species. Among the 10 primers used four are identified as the key primers capable of distinguishing all the Indian seagrasses with a high degree of polymorphism and bringing representative polymorphic alleles in all the tested seagrasses. From the present investigation, this study shows that the RAPD marker technique can be used not only as a tool to analyse genetic diversity but also to resolve the taxonomic uncertainties existing in the Indian seagrasses. The efficiency of these primers in bringing out the genetic polymorphism or homogeneity among different populations of theHalophilaandHalodulecomplex still has to be tested before recommending these primers as an identification tool for Indian seagrasses.
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Watson, RA, RG Coles, and WJ Lee Long. "Simulation estimates of annual yield and landed value for commercial penaeid prawns from a tropical seagrass habitat, Northern Queensland, Australia." Marine and Freshwater Research 44, no. 1 (1993): 211. http://dx.doi.org/10.1071/mf9930211.
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Concern over the loss of seagrass habitat has prompted examination of the value of the production of commercial prawns from such habitat. Cairns Harbour in tropical northern Queensland has 876 ha of mixed seagrasses, dominated by Zostera capricorni and Halodule pinifolia, that support a multispecies commercial penaeid prawn fishery offshore. Densities of juvenile commercial prawns estimated from seagrass surveys were used to project estimates of annual yield and landed value, using a deterministic simulation model employing lunar-period time steps. Estimates of the potential total annual yield from Cairns Harbour seagrasses for the three major commercial prawn species (Penaeus esculentus, P. semisulcatus and Metapenaeus endeavouri) were 178 t (range 81-316 t) year-1 with a landed value of $A1.2 million (range $0.6 million to $2.2 million) year-1.
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S, Velmani, Santhosh C, Nithya P, Balamurugan V, Archana L, Lavanya G, Sowmiya M, Anjalidevi B, Viji M, and Maruthupandian A. "Phytochemical and biochemical analyses of Syringodium isoetifolium (Asch.) Dandy." International Journal of Zoology and Applied Biosciences 7, no. 6 (November 5, 2022): 7–13. http://dx.doi.org/10.55126/ijzab.2022.v07.i06.sp001.
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Seagrasses are the flowering plant found in marine ecosystem. It has many bioactive compounds with various applications including pharmaceutical and nutraceutical. The present study has been aimed to evaluate the nutritional composition and antioxidant potentials of the Seagrass Syringodium isoetifolium. The Seagrass exhibits significant amounts of biochemical and phytochemical compositions. In in-vitro antioxidant, DPPH, ABTS and Hydroxyl radical scavenging assay showed that S. isoetifolium was an excellent scavenger for free radicals. The results suggest that the Seagrass S. isoetifolium may be used as a very good renewable marine resource for potential biomedical applications in future
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Sani, D. A., and M. Hashim. "SATELLITE-BASED MAPPING OF ABOVE-GROUND BLUE CARBON STORAGE IN SEAGRASS HABITAT WITHIN THE SHALLOW COASTAL WATER." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W16 (October 1, 2019): 587–93. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w16-587-2019.
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Abstract. These Mapping and estimation of seagrass total above-ground carbon (STAGC) using satellite-based techniques are required to fast-track the achievement of the 2020 agenda on Sustainable Development Goals (SDG) 14th. This attainment is possible as seagrass habitats provide a critical coastal ecosystem for storing blue carbon stock, sediment accumulation, fisheries production and stabilisation of coastal environment. However, seagrasses are generally declining across the globe due to anthropogenic disturbance, resulting in a prolonged growth rate of seagrasses that varies according to the species compositions. Therefore, this study aims at mapping and estimation of seagrass total above-ground carbon (STAGC) using Landsat ETM+ in the coastline of Penang. These satellite images were calibrated with Bottom Reflected Index (BRI) and Depth Invariant Index (DII) to compare the estimate of the STAGC for more accuracy. The leaving radiances of the seagrass were correlated with the corresponding in-situ measurements to predict seagrass carbon. This established relationship with BRI image shown a healthy correlation with STAGB (R2 = 0.992, p &leq; 0.001). Whereas the STAGB versus DII relationship has less accuracy (R2 = 0.955, p &leq; 0.01), adjusted R2 = 0.980 and 0.978 were recorded for both BRI and DII STAGC estimate using the logistic model. Therefore, careful management of blue carbon stock is essential, as this study shall contribute to achieving targets 14.2 and 14.5 of SDG 14th by the United Nations.