Journal articles on the topic 'Seagrass loss'
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1
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.
Abstract:
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.
2
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.
Abstract:
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.
3
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.
Abstract:
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.
4
Duarte, Carlos M. "The future of seagrass meadows." Environmental Conservation 29, no. 2 (June 2002): 192–206. http://dx.doi.org/10.1017/s0376892902000127.
Abstract:
Seagrasses cover about 0.1–0.2% of the global ocean, and develop highly productive ecosystems which fulfil a key role in the coastal ecosystem. Widespread seagrass loss results from direct human impacts, including mechanical damage (by dredging, fishing, and anchoring), eutrophication, aquaculture, siltation, effects of coastal constructions, and food web alterations; and indirect human impacts, including negative effects of climate change (erosion by rising sea level, increased storms, increased ultraviolet irradiance), as well as from natural causes, such as cyclones and floods. The present review summarizes such threats and trends and considers likely changes to the 2025 time horizon. Present losses are expected to accelerate, particularly in South-east Asia and the Caribbean, as human pressure on the coastal zone grows. Positive human effects include increased legislation to protect seagrass, increased protection of coastal ecosystems, and enhanced efforts to monitor and restore the marine ecosystem. However, these positive effects are unlikely to balance the negative impacts, which are expected to be particularly prominent in developing tropical regions, where the capacity to implement conservation policies is limited. Uncertainties as to the present loss rate, derived from the paucity of coherent monitoring programmes, and the present inability to formulate reliable predictions as to the future rate of loss, represent a major barrier to the formulation of global conservation policies. Three key actions are needed to ensure the effective conservation of seagrass ecosystems: (1) the development of a coherent worldwide monitoring network, (2) the development of quantitative models predicting the responses of seagrasses to disturbance, and (3) the education of the public on the functions of seagrass meadows and the impacts of human activity.
5
Zhang, Yong, Xinping Yu, Zuoyi Chen, Qiuzhen Wang, Jiulong Zuo, Shanshan Yu, and Ran Guo. "A Mini-Review of Seagrass Bed Pollution." Water 15, no. 21 (October 27, 2023): 3754. http://dx.doi.org/10.3390/w15213754.
Abstract:
Due to climate change and human activities, seagrass is in crisis as the coverage of seagrass declines at an accelerated rate globally. In this paper, the severe challenges of seagrass ecosystem were briefly reviewed, including adverse effects of natural factors and human activities on seagrass beds. The research status of pollutants and pollution in seagrass bed ecosystem was reviewed, the future research directions in related fields were proposed as well. The eutrophication in coastal waters and discharge of pollutants such as sulfide, heavy metals, organic matter and microplastics caused by human activities are important reasons for seagrass loss. In addition, environmental stressors lead to reduced immunity and decreased resistance of seagrass to various pathogens, leading to seagrass wasting diseases. Future studies concerning the influence of novel pollutants, i.e., plastic waste on non-native algae, microorganisms and seagrasses, as well as their interrelationships, will be of vital importance. In addition, researches on seagrass wasting diseases and their pathogens should be much accounted in China, to fill in gaps in related fields and improve the response ability to emergent seagrass diseases. In conclusion, this review was proposed to arouse the concern about the seagrass bed pollution, and provide possible enlightening information for the protection and restoration of this significant ecosystem.
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Marliana, Isnaini, Hilman Ahyadi, Dining Aidil Candri, Immy Suci Rohyani, Sukmaraharja Aulia Rachman Tarigan, Pardede Shinta Trilestari, Sebastian Aviandhika, and Sri Puji Astuti. "Estimasi Simpanan Karbon dan Status Kesehatan Padang Lamun di Pulau Kelapa Kabupaten Bima." Bioscientist : Jurnal Ilmiah Biologi 9, no. 1 (June 30, 2021): 72. http://dx.doi.org/10.33394/bjib.v9i1.3542.
Abstract:
The seagrass community are angiosperm plant communities that mostly grow in shallow marine waters. The community has an ecological role and function, both as a habitat for various types of biota and as a carbon sink. The purpose of this study was to determine the type and condition of the seagrass ecosystem in Kelapa Island based on the percentage of cover; and to determine the estimated carbon stocks of seagrasses contained. Seagrass community data collection was carried out in September-October 2020 in the waters of Kelapa Island, Bima Regency, West Nusa Tenggara Province. A quadratic transect was used for data collection of seagrass cover, and analysis of seagrass community cover using the PhotoQuad application, followed by determining the condition of the seagrass community ecosystem, and analysis of estimated carbon storage using the Loss On Ignition (LOI) method. The results showed that there were 4 types of seagrass found, consisting of: Thalassia hemprichii, Halophila ovalis, Cymodocea rotundata, and Halodule pinifolia. The percentage of seagrass cover is 52.31%, because it is less than 60%, the health status of seagrass beds is unhealthy based on the Decree of the Minister of the Environment Number 200 of 2004. Total carbon storage is 16.1 gr.Cm-2. Thalassia hemprichii as the highest carbon storage species was 8.27 gr.Cm-2.
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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.
Abstract:
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
8
Scott, Abigail L., Paul H. York, and Michael A. Rasheed. "Spatial and Temporal Patterns in Macroherbivore Grazing in a Multi-Species Tropical Seagrass Meadow of the Great Barrier Reef." Diversity 13, no. 1 (January 2, 2021): 12. http://dx.doi.org/10.3390/d13010012.
Abstract:
Macroherbivory is an important process in seagrass meadows worldwide; however, the impact of macroherbivores on seagrasses in the Great Barrier Reef (GBR) has received little attention. We used exclusion cages and seagrass tethering assays to understand how the intensity of macroherbivory varies over space and time in the seagrass meadows around Green Island (Queensland), and what impact this has on overall meadow structure. Rates of macroherbivory were comparatively low, between 0.25–44% of daily seagrass productivity; however, rates were highly variable over a one-year period, and among sites. Loss of seagrass material to macroherbivory was predominantly due to fish; however, urchin herbivory was also taking place. Macroherbivory rates were of insufficient intensity to impact overall meadow structure. No macroherbivory events were identified on video cameras that filmed in the day, indicating that feeding may be occurring infrequently in large shoals, or at night. While relatively low compared to some meadows, seagrass macroherbivory was still an important process at this site. We suggest that in this highly protected area of the GBR, where the ecosystem and food webs remain largely intact, macroherbivory was maintained at a low level and was unlikely to cause the large-scale meadow structuring influence that can be seen in more modified seagrass systems.
9
Salsabila, H. N., P. Wicaksono, and P. Danoedoro. "Seagrass Aboveground Carbon Stock Mapping using PlanetScope SuperDove Imagery in Nemberala, Rote Island, East Nusa Tenggara." IOP Conference Series: Earth and Environmental Science 1291, no. 1 (January 1, 2024): 012013. http://dx.doi.org/10.1088/1755-1315/1291/1/012013.
Abstract:
Abstract Seagrass ecosystem is natural objects that can be used to adapt and mitigate climate change through blue carbon sequestration. There are 16 seagrass species in Indonesia and the high diversity of these species supports the high potential of carbon that can be absorbed and stored. This study aimed to develop a general equation to estimate seagrass aboveground carbon stock (AGC) from the percent cover (PC), and to map seagrass AGC using PlanetScope imagery in Nemberala, Rote Island. Nemberala has very diverse seagrass species such as Enhalus acoroides (Ea), Cymodocea rotundata (Cr), Halophila ovalis (Ho), Syringodium isoetifolium (Si), Thalassodendron ciliatum (Tc) and Thalassia hemprichii (Th). The results of laboratory analysis to obtain the value of carbon stocks using the Loss on Ignition method from each species were 0.016, 0.004, 0.001, 0.002, 0.001, and 0.0001 (gC/leaf) for Ea, Th, Cr, Si, Tc, and Ho, respectively. The general equation for predicting AGC from PC is SeagrassAGC = (0.051*SeagrassPC) – 0.635 with r of 0.61 and R2 of 0.36. This formula will be applied to convert field seagrass PC data to AGC, which will then be used to train and test the accuracy of seagrass AGC mapping based on PlanetScope SuperDove 8 bands image.
10
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.
Abstract:
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.
11
Tamondong, A., T. Nakamura, T. E. A. Quiros, and K. Nadaoka. "TIME SERIES ANALYSIS FOR MONITORING SEAGRASS HABITAT AND ENVIRONMENT IN BUSUANGA, PHILIPPINES USING GOOGLE EARTH ENGINE." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2021 (June 28, 2021): 109–16. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2021-109-2021.
Abstract:
Abstract. Seagrasses are marine flowering plants which are part of a highly productive coastal ecosystem and play key roles in the coastal processes. Unfortunately, they are declining in area coverage globally, and seagrass losses can be attributed to climate change such as sea-level rise, increase in sea surface temperature, and decrease in salinity, as well as human-related activities. The objective of this research is to assess the historical changes in the seagrass habitat and environment of Busuanga, Philippines using time series data available in the Google Earth Engine (GEE) platform. These include satellite data such as MODIS, Landsat 5, 7, and 8, and SeaWIFS. Reanalysis data such as HYCOM was also utilized in this research. Results from HYCOM data show that there has been a 0.0098 °C increase in the sea surface temperature per decade in Busuanga while MODIS data indicates an increase of 0.0045 °C per decade. Moreover, HYCOM data also shows an overall average of 0.76 mm in sea surface elevation anomaly and a decreasing trend in salinity values at 0.0026 psu per decade. Chlorophyll-a concentration has a minimal increase based on results from MODIS and SeaWIFS. Aside from changes in water parameters, changes in the land also affect seagrasses. Forest loss may cause increased siltation in the coastal ecosystem which can lead to seagrass loss. Based on the results of Landsat satellite image processing, there has been forest cover loss in Busuanga with the highest loss occurring in 2013 when super typhoon Yolanda ravaged the island. Lastly, results from the linear spectral unmixing of 778 Landsat images from 1987–2000 show that the average percent cover of seagrasses in Busuanga were declining through the years.
12
Vernianda, Cindy, Ni Luh Watiniasih, Elok Faiqoh, and I. Nyoman Giri Putra. "Analisis Karbon dalam Sedimen pada Ekosistem Lamun di Teluk Gilimanuk, Bali." Journal of Marine Research and Technology 5, no. 2 (August 31, 2022): 105. http://dx.doi.org/10.24843/jmrt.2022.v05.i02.p09.
Abstract:
The increased CO2 emissions in the atmosphere have caused several environmental changes. Therefore, a larger CO2 absorption capacity is required. Seagrass can absorb carbon relatively fast and able to store it. Seagrass beds can trap sediment, so the absorption of organic carbon from the sediment by seagrass can be influenced by the size of the substrate. It has been found that the larger the substrate grain, the lower the ability of plants to absorb the organic matter. This study aimed to determine the seagrass density and cover as well as carbon storage in seagrass bed sediments. The variable measured was Sediment-Organic Carbon Content (S-OCC) and Sediment-Organic Carbon Stock (S-OCS) of seagrass ecosystems in Gilimanuk Bay. Employing purposive sampling, 20 sampling points were selected randomly where seagrass beds were present. The data were obtained using a 1×1m quadrant transect. The carbon content of the sediment was calculated by the Loss of Ignition (LOI) method by removing organic matter at a temperature of 600? in a furnace. This study found four seagrass species: Enhalus acoroides, Cymodocea rotundata, Cymodocea serrulate, and Halophila ovalis. The average density of seagrasses in this habitat ranged from 17 – 179 #/m2, with seagrass cover values ranging from 25 to 100%. The sediment carbon content, measured as carbon stock, on seagrass ecosystems at Gilimanuk Bay was 0.21% - 5.51% for S-OCC and 0.002 – 0.059 g Corg cm-3 for S-OCS. Total S-OCS in Gilimanuk Bay was 11165.84 Mg g Corg.
13
Unsworth, Richard K. F., Leanne C. Cullen-Unsworth, Benjamin L. H. Jones, and Richard J. Lilley. "The planetary role of seagrass conservation." Science 377, no. 6606 (August 5, 2022): 609–13. http://dx.doi.org/10.1126/science.abq6923.
Abstract:
Seagrasses are remarkable plants that have adapted to live in a marine environment. They form extensive meadows found globally that bioengineer their local environments and preserve the coastal seascape. With the increasing realization of the planetary emergency that we face, there is growing interest in using seagrasses as a nature-based solution for greenhouse gas mitigation. However, seagrass sensitivity to stressors is acute, and in many places, the risk of loss and degradation persists. If the ecological state of seagrasses remains compromised, then their ability to contribute to nature-based solutions for the climate emergency and biodiversity crisis remains in doubt. We examine the major ecological role that seagrasses play and how rethinking their conservation is critical to understanding their part in fighting our planetary emergency.
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Insalaco, Stephanie A., Hannah V. Herrero, Russ Limber, Clancy Oliver, and William B. Wolfson. "Monitoring an Ecosystem in Crisis: Measuring Seagrass Meadow Loss Using Deep Learning in Mosquito Lagoon, Florida." Photogrammetric Engineering & Remote Sensing 90, no. 6 (June 1, 2024): 363–70. http://dx.doi.org/10.14358/pers.24-00001r2.
Abstract:
The ecosystem of Mosquito Lagoon, Florida, has been rapidly deteriorating since the 2010s, with a notable decline in keystone seagrass species. Seagrass is vital for many species in the lagoon, but nutrient overloading, algal blooms, boating, manatee grazing, and other factors have led to its loss. To understand this decline, a deep neural network analyzed Landsat imagery from 2000 to 2020. Results showed significant seagrass loss post-2013, coinciding with the 2011–2013 super algal bloom. Seagrass abundance varied annually, with the model performing best in years with higher seagrass coverage. While the deep learning method successfully identified seagrass, it also revealed that recent seagrass coverage is almost non-existent. This monitoring approach could aid in ecosystem recovery if coupled with appropriate policies for Mosquito Lagoon's restoration.
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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.
Abstract:
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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Coles, Rob, Fred Short, Miguel Fortes, and John Kuo. "Twenty years of seagrass networking and advancing seagrass science: The International Seagrass Biology Workshop Series." Pacific Conservation Biology 20, no. 1 (2014): 8. http://dx.doi.org/10.1071/pc140008.
Abstract:
SEAGRASSES are a group of some 72 species of marine flowering plants found in the world’s shallow coastal oceans (Green and Short 2003, Short et al. 2011). There is now scientific consensus that they create an important marine habitat not only by themselves, but also as a component of more complex ecosystems within marine coastal zones. Seagrasses contribute to the health of coral reefs and mangroves, salt marshes and oyster reefs (Dorenbosch et al. 2004; Duke et al. 2007; Heck et al. 2008; Unsworth et al. 2008). Seagrasses have high primary productivity and are a basis of many marine food webs through direct herbivory and the through a detrital cycle (Hemminga and Duarte, 2000). They have enormous value in providing nutrients (N and P) and organic carbon to other parts of the oceans, including the deep sea, and they contribute significantly to carbon sequestration (Suchanek et al. 1985; Duarte et al. 2005). Armed with this knowledge today it is interesting to remember that it is only just over a hundred years since scientists first began speculating on the roles and values of seagrass in the marine environment, with the first focus occurring in Europe on eelgrass (Zostera marina). Many at the time discounted seagrass as an important primary producer (den Hartog 1980). It was not until after the 1930s, when vast areas of Zostera marina were lost in the northern hemisphere from a wasting disease that scientists and governments started to understand and investigate the value of seagrass to coastal ecosystems (Milne and Milne 1951). The loss of Zostera marina led to obvious declines in migratory waterfowl, crustaceans, finfish and shellfish populations (Thayer et al. 1984) In response to those concerns about ongoing losses of Zostera marina and other seagrass species, a meeting of scientists in Fairbanks, Alaska in early 1973 decided to coordinate seagrass research globally. This led to the first International Seagrass Workshop being organized and held in Leiden, The Netherlands, later that year. The report of that conference (McRoy and Helfferich 1977) makes interesting reading, looking back from the perspective of the 21st century. There is only one contribution from the southern hemisphere (Larkum 1977) with Australia referred to as a “little known region”. What we now know as the centre of seagrass biodiversity, Insular Southeast Asia and the broader Indo Pacific region, receives no mention at all. A significant and long-lasting outcome of the Leiden meeting was the birth of the journal “Aquatic Botany”.
17
Ballard, Megan, Kevin M. Lee, Kyle Capistrant-Fossa, Andrew R. McNeese, Colby W. Cushing, Thomas S. Jerome, Preston S. Wilson, and Kenneth H. Dunton. "Acoustical methods for remote sensing in seagrass meadows." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A229. http://dx.doi.org/10.1121/10.0018735.
Abstract:
Seagrasses provide a multitude of ecosystem services and act as important carbon sinks. However, seagrass habitats are declining globally, and they are among the most threatened ecosystems on earth. For these reasons, long-term and continuous measurements of seagrass parameters are of primary importance for ecosystem health assessment and sustainable management. After a brief historical overview, this talk will present results from both active and passive acoustical methods for ecosystem monitoring in seagrass meadows. From a propagation perspective, gas bodies contained within the seagrass tissue as well as photosynthetic-driven bubble production results in attenuation and scattering of sound that produces increased transmission loss. For the passive approach, the detachment of gas bubbles from the plants is an important component of the ambient soundscape. Examples of both techniques will be presented based on data collected as part of an 18-month continuous deployment of an acoustical measurement system operating in a moderately dense seagrass bed dominated by Thalassia testudinum (turtle grass) in Corpus Christi Bay, Texas. The data show annual trends related to the seasonal growth pattern of Thalassia as well as diurnal trends correlated with photosynthetically active radiation. [Work supported by NSF.]
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Garcias-Bonet, Neus, Marco Fusi, Muhammad Ali, Dario R. Shaw, Pascal E. Saikaly, Daniele Daffonchio, and Carlos M. Duarte. "High denitrification and anaerobic ammonium oxidation contributes to net nitrogen loss in a seagrass ecosystem in the central Red Sea." Biogeosciences 15, no. 23 (December 11, 2018): 7333–46. http://dx.doi.org/10.5194/bg-15-7333-2018.
Abstract:
Abstract. Nitrogen loads in coastal areas have increased dramatically, with detrimental consequences for coastal ecosystems. Shallow sediments and seagrass meadows are hotspots for denitrification, favoring N loss. However, atmospheric dinitrogen (N2) fixation has been reported to support seagrass growth. Therefore, the role of coastal marine systems dominated by seagrasses in the net N2 flux remains unclear. Here, we measured denitrification, anaerobic ammonium oxidation (anammox), and N2 fixation in a tropical seagrass (Enhalus acoroides) meadow and the adjacent bare sediment in a coastal lagoon in the central Red Sea. We detected high annual mean rates of denitrification (34.9±10.3 and 31.6±8.9 mg N m−2 d−1) and anammox (12.4±3.4 and 19.8±4.4 mg N m−2 d−1) in vegetated and bare sediments. The annual mean N loss was higher (between 8 and 63-fold) than the N2 fixed (annual mean = 5.9±0.2 and 0.8±0.3 mg N m−2 d−1) in the meadow and bare sediment, leading to a net flux of N2 from sediments to the atmosphere. Despite the importance of this coastal lagoon in removing N from the system, N2 fixation can contribute substantially to seagrass growth since N2 fixation rates found here could contribute up to 36 % of plant N requirements. In vegetated sediments, anammox rates decreased with increasing organic matter (OM) content, while N2 fixation increased with OM content. Denitrification and anammox increased linearly with temperature, while N2 fixation showed a maximum at intermediate temperatures. Therefore, the forecasted warming could further increase the N2 flux from sediments to the atmosphere, potentially impacting seagrass productivity and their capacity to mitigate climate change but also enhancing their potential N removal.
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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.
Abstract:
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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Rahmadanti, Karla Lutfia, Gunawan Widi Santosa, and Rini Pramesti. "Penyerapan Karbon Pada Vegetasi Lamun Di Pantai Legon Bajak Pulau Kemujan, Taman Nasional Karimunjawa." Journal of Marine Research 12, no. 3 (June 17, 2023): 474–82. http://dx.doi.org/10.14710/jmr.v12i3.37564.
Abstract:
Gas karbondioksida yang tinggi di atmosfer dapat memicu pemanasan global. Upaya mitigasi diperlukan untuk mengurangi dampak buruk, salah satunya dengan pemanfaatan lamun sebagai penyerap karbon yang dikenal dengan blue carbon. Penelitian ini bertujuan mengetahui estimasi biomassa dan kandungan karbon pada vegetasi lamun di Pantai Legon Bajak Pulau Kemujan, Taman Nasional Karimunjawa. Penelitian dilakukan pada 28 – 29 November 2021 dengan dua stasiun. Analisis vegetasi dilakukan menggunakan metode line transect quadrant, yang mengacu pada buku Panduan Monitoring Padang Lamun LIPI. Pengambilan sampel lamun menggunakan seagrass core. Biomassa lamun terbagi menjadi bagian atas substrat (daun) dan bawah substrat (akar dan rhizoma). Nilai biomassa lamun ditentukan melalui berat kering dari dengan cara pengeringan. Nilai kandungan karbon diperoleh melalui metode LOI (Loss of Ignition) atau pengabuan kering.Hasil penelitian diperoleh 5 jenis lamun, antara lain Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Halophila ovalis dan Halodule uninervis. Kondisi padang lamun tergolong memiliki penutupan sedang. Nilai biomassa yang terdapat di bawah substrat (585 g/m2) lebih besar dibandingkan yang terdapat di atas substrat (346,73 g/m2), diikuti dengan kandungan karbon di bawah substrat (182,54 gC/m2)yang lebih besar dibandingkan atas substrat (119,43 gC/m2). Vegetasi lamun di lokasi penelitian berpotensi menyimpan karbon sebesar 301,97 gC/ m2. The high level of carbondioxide gas in the atmosphere can trigger global warming. Mitigation efforts are needed to reduce adverse impacts, such as by the optimization of seagrass as a carbon sink which is known as blue carbon. This study aims to determine the estimation of biomass and carbon content in seagrass vegetation at Legon Bajak Beach, Kemujan Island, Karimunjawa National Park. The research was conducted on 28 – 29 November 2021 at two stations. Vegetation analysis was conducted by using the line transect quadrant method, which refers to the LIPI Seagrass Monitoring Guidebook. Seagrass sample was collected by using seagrass core. Seagrass biomass is divided into above substrate (leaves) and below substrate (roots and rhizomes). The value of seagrass biomass was determined through dry weight by drying process in the oven. The value of carbon content in seagrasses is obtained through the LOI (Loss of Ignition) method or dry ignition.The results o the study obtained 5 species of seagrasses, including E. acoroides, T. hemprichii, C. rotundata, H. ovalis and H. uninervis. The condition of seagrass meadows is classified as having moderate cover. The value of the biomass below substrate (585 g/m2) is greater than the value of biomass above the substrate (346.73 g/m2), followed by the value of carbon content below the substrate (182.54 gC/m2) which is greater than above substrate (119.43 gC/m2). Seagrass vegetation in the study site has the potential to store 301.97 gC/m2 of carbon.
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Harcourt, William D., Robert A. Briers, and Mark Huxham. "The thin(ning) green line? Investigating changes in Kenya's seagrass coverage." Biology Letters 14, no. 11 (November 2018): 20180227. http://dx.doi.org/10.1098/rsbl.2018.0227.
Abstract:
Knowledge of seagrass distribution is limited to a few well-studied sites and poor where resources are scant (e.g. Africa), hence global estimates of seagrass carbon storage are inaccurate. Here, we analysed freely available Sentinel-2 and Landsat imagery to quantify contemporary coverage and change in seagrass between 1986 and 2016 on Kenya's coast. Using field surveys and independent estimates of historical seagrass, we estimate total cover of Kenya's seagrass to be 317.1 ± 27.2 km 2 , following losses of 0.85% yr −1 since 1986. Losses increased from 0.29% yr −1 in 2000 to 1.59% yr −1 in 2016, releasing up to 2.17 Tg carbon since 1986. Anecdotal evidence suggests fishing pressure is an important cause of loss and is likely to intensify in the near future. If these results are representative for Africa, global estimates of seagrass extent and loss need reconsidering.
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Titioatchasai, Jatdilok, Komwit Surachat, Ekkalak Rattanachot, Piyalap Tuntiprapas, and Jaruwan Mayakun. "Assessment of Diversity of Marine Organisms among Natural and Transplanted Seagrass Meadows." Journal of Marine Science and Engineering 11, no. 10 (October 6, 2023): 1928. http://dx.doi.org/10.3390/jmse11101928.
Abstract:
Seagrass ecosystems have been declining, and restorations are conducted in many parts of the world to compensate for habitat loss and restore the ecosystem services seagrasses provide. Assessment of transplantation success requires the monitoring of the level of biodiversity between the donor and transplanted sites. In this study, we assessed a seagrass ecosystem after restoration in terms of the diversity of marine organisms using environmental DNA (eDNA) to compare four sites: (1) bare sand, (2) a natural meadow of Cymodocea serrulata, (3) a natural meadow of Halophila ovalis, and (4) a transplanted seagrass meadow. The results showed the presence of 3 domains, 34 phyla, 59 classes, 92 orders, 155 families, 156 genera, and 121 species. Proteobacteria, Actinobacteria, Cyanobacteria, and Bacteroidetes were the dominant bacterial phyla. Among eukaryotes, Phragmoplastophyta/Charophyta (epiphytes), Ascomycota (fungi), Cnidaria (jelly fish), and Arthropoda (Crabs and bivalves) were the dominant phyla. Dugong tails and commercial species (sea cucumber, dog conch, and swimming crab) have been observed in both the natural and transplanted meadows. Relative abundance among the four sites was significantly different. There were no differences in species richness and evenness between the four sites and no differences in species richness and evenness between the natural meadows and the transplanted seagrass meadow. It is possible that transplanted seagrass meadow can be successfully restored and established and can provide habitat for fauna and microbes. Additionally, fauna are not limited in their capacity to move between the natural and transplanted habitats. This study provides an assessment of biodiversity of restored seagrass patches and a better understanding of a seagrass ecosystem after restoration. However, to assess seagrass ecosystem services after restoration and the success of restoration actions, long-term monitoring of marine organism diversity and additional assessments are needed.
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Eklöf, Johan S., Kathryn McMahon, and Paul S. Lavery. "Effects of multiple disturbances in seagrass meadows: shading decreases resilience to grazing." Marine and Freshwater Research 60, no. 12 (2009): 1317. http://dx.doi.org/10.1071/mf09008.
Abstract:
Ecosystem shifts are often associated with multiple disturbances, but limited knowledge on the mechanisms involved hampers management. This study investigated how short-term shading affected the resilience of the seagrass Halophila ovalis to grazing by black swans (Cygnus atratus) – a historically dominant grazer currently recovering from hunting and habitat loss – in south-western Australian estuaries, using field surveys and a grazing-shading experiment. Black swans were heterogeneously distributed and, in a high-density site, consumed 23% of seagrass production. Seagrasses recovered rapidly from a single disturbance (i.e. short-term shading or grazing), even though shading alone halved carbohydrate content. When seagrasses were exposed to both disturbances, recovery depended on the type of grazing; where grazing was confined to leaves, leaf densities recovered within 3 weeks, but where grazing was on both leaves and rhizomes there was no recovery. Shading increased the frequency of apex initiation, as did rhizome grazing, but only if the plants had not been shaded. This indicates that shading alters the flow of energy needed to produce apices and leaves following disturbance on rhizomes. Based on the historical swan densities and continuing recurring phytoplankton blooms, management actions reintroducing swans without controlling algal blooms could have an on impact seagrass resilience and associated organisms.
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Traganos, Dimosthenis, Bharat Aggarwal, Dimitris Poursanidis, Konstantinos Topouzelis, Nektarios Chrysoulakis, and Peter Reinartz. "Towards Global-Scale Seagrass Mapping and Monitoring Using Sentinel-2 on Google Earth Engine: The Case Study of the Aegean and Ionian Seas." Remote Sensing 10, no. 8 (August 5, 2018): 1227. http://dx.doi.org/10.3390/rs10081227.
Abstract:
Seagrasses are traversing the epoch of intense anthropogenic impacts that significantly decrease their coverage and invaluable ecosystem services, necessitating accurate and adaptable, global-scale mapping and monitoring solutions. Here, we combine the cloud computing power of Google Earth Engine with the freely available Copernicus Sentinel-2 multispectral image archive, image composition, and machine learning approaches to develop a methodological workflow for large-scale, high spatiotemporal mapping and monitoring of seagrass habitats. The present workflow can be easily tuned to space, time and data input; here, we show its potential, mapping 2510.1 km2 of P. oceanica seagrasses in an area of 40,951 km2 between 0 and 40 m of depth in the Aegean and Ionian Seas (Greek territorial waters) after applying support vector machines to a composite of 1045 Sentinel-2 tiles at 10-m resolution. The overall accuracy of P. oceanica seagrass habitats features an overall accuracy of 72% following validation by an independent field data set to reduce bias. We envision that the introduced flexible, time- and cost-efficient cloud-based chain will provide the crucial seasonal to interannual baseline mapping and monitoring of seagrass ecosystems in global scale, resolving gain and loss trends and assisting coastal conservation, management planning, and ultimately climate change mitigation.
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Wismar, Jan Ericson, Wilis Ari Setyati, and Ita Riniatsih. "Potensi Penyimpanan Karbon Pada Vegetasi Padang Lamun di Perairan Pulau Besar Utara, Sikka, Maumere, Nusa Tenggara Timur." Buletin Oseanografi Marina 10, no. 1 (January 19, 2021): 51–60. http://dx.doi.org/10.14710/buloma.v10i1.27223.
Abstract:
Konsep blue carbon adalah salah satu upaya untuk mengurangi emisi gas karbon pemicu pemanasan global dengan cara memanfaatkan vegetasi pesisir sebagai penyerap karbon. Ekosistem lamun merupakan salah satu ekosistem pesisir yang dapat menyerap karbon dalam jumlah besar. Penelitian ini bertujuan untuk mengetahui kondisi lamun dan kandungan karbon pada lamun di Perairan Pulau Besar Utara, Maumere, Sikka. Pengamatan lamun menggunakan transek kuadrat 50x50cm menurut panduan LIPI. Sampling lamun dilakukan acak menggunakan seagrass core berdiameter 15 cm di setiap lokasi. Perhitungan kandungan karbon menggunakan metode Loss On Ignition (LOI) yang kemudian dikonversikan dengan nilai biomassa pada setiap titiknya. Jenis lamun yang ditemukan sebanyak 4 spesies yaitu Enhalus acoroides, Thalassia hemprichii,, Cymodocea rotundata,dan Syringodium isoetifolium. Lokasi pengamatan memiliki tutupan lamun sangat padat. Nilai biomassa dibawah dan diatas substrat pada lokasi pengamatan didapat nilai 424,60 gbk/m2 dan 79,67 gbk/m2. Total kandungan karbon pada lokasi pengamatan adalah 41,95 gC/m2. Kandungan karbon terbesar disimpan pada jaringan lamun (akar dan rhizoma) dengan spesies E. acoroides sebagai penyumbang nilai biomassa dan kandungan karbon tertinggi. Lokasi perairan Pulau Besar Utara, Maumere memiliki kondisi perairan yang baik dengan kerapatan lamun yang tinggi, secara umum kandungan karbon yang terdapat pada perairan tersebut memiliki kandungan yang tinggi. Kondisi lamun yang baik akan memiliki simpanan karbon yang baik dan hal ini merupakan salah satu upaya dalam mitigasi perubahan iklim sekaligus menjaga kelestarian laut. The concept of blue carbon is one of the efforts to reduce carbon gas emissions that trigger global warming by utilizing coastal vegetation as a carbon sink. Seagrass ecosystems are one of the coastal ecosystems that can absorb large amounts of carbon. This study aims to find seagrass conditions and carbon content in seagrasses on the waters of Besar Utara Island, Maumere, Sikka. Seagrass observations used a 50x50cm quadrant transect according to the LIPI guideline, 2017. Seagrass sampling was using seagrass cores with 15cm diameter in each location. Calculation of carbon content using the Loss On Ignition (LOI) method which is then converted to biomass values at each point. Seagrass species found in location sampling were 4 species, namely Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, and Syringodium isoetifolium. The Location has very dense seagrass cover. Biomass values below and above the substrate at location sampling (424.60 gbk / m2 and 79.67 gbk / m2). The total carbon content in location sampling is 41.95 gC / m2. The largest carbon content is stored in seagrass tissues (roots and rhizomes) with E. acoroides as a contributor to the highest biomass and carbon content. The location of Besar North island, Maumere has good water conditions with high seagrass density, in general the carbon storage at the location of Besar North island is high condition. Seagrass with good condition will have good carbon storage and this is one of the efforts in mitigating climate change at once preserving the sea.
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Hidayah, Nur, Siti Aishah Tahirin, Mohammad Fairoz, and Mohammad Rozaimi. "Carbon stock and ?13C data of sediment samples collected from a tropical seagrass meadow in Malaysia." Plant Science Today 6, no. 2 (April 10, 2019): 132–36. http://dx.doi.org/10.14719/pst.2019.6.2.489.
Abstract:
Seagrass ecosystems are considered as major blue carbon sinks, thus contributing directly to the mitigation of climate change by storing carbon in their habitats. However, empirical data for carbon stocks in Malaysia seagrass meadow sediment remain unreported in a standardised format. This paper presents data on organic (OC) and inorganic carbon (IC) stocks, and stable isotope signatures of carbon (?13C) in bulk seagrass sediments collected from Sungai Pulai estuary (Johor, Malaysia). Within this estuary, seagrasses form shoals at Tanjung Adang and Merambong. Organic carbon and ?13C values in bulk sediment were analysed by an elemental analyser and a continuous flow isotope-ratio mass spectrometer, respectively, while sediment IC data was derived from loss-on-ignition calculations of sample mass differences. The data from these samples are presented as downcore profile of OC (values range at 0.14% to 2.49%), IC (0.16% to 5.29%), ?13C values of organic matter (-27.9‰ to -20.4‰), and cumulative carbon stocks (1.03-3.39 kg OC m-2 and 0.76-2.84 kg IC m-2) in the top 30 cm of sediments. This dataset is applicable for regional and local blue carbon studies, which would allow insights into carbon sink and carbon cycling capacity, in addition to gaining insights into the provenances of carbon stored in seagrass meadows.
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Carroll, Elizabeth W., and Amy L. Freestone. "Habitat isolation interacts with top-down and bottom-up processes in a seagrass ecosystem." PLOS ONE 18, no. 7 (July 26, 2023): e0289174. http://dx.doi.org/10.1371/journal.pone.0289174.
Abstract:
Habitat loss is accelerating at unprecedented rates, leading to the emergence of smaller, more isolated habitat remnants. Habitat isolation adversely affects many ecological processes independently, but little is known about how habitat isolation may interact with ecosystem processes such as top-down (consumer-driven) and bottom-up (resource-driven) effects. To investigate the interactive influence of habitat isolation, resource availability and consumer distribution and impact on community structure, we tested two hypotheses using invertebrate and algal epibionts on temperate seagrasses, an ecosystem of ecological and conservation importance. First, we hypothesized that habitat isolation will change the structure of the seagrass epibiont community, and isolated patches of seagrass will have lower epibiont biomass and different epibiont community composition than contiguous meadows. Second, we hypothesized that habitat isolation would mediate top-down (i.e., herbivory) and bottom-up (i.e., nutrient enrichment) control for algal epibionts. We used observational studies in natural seagrass patches and experimental artificial seagrass to examine three levels of habitat isolation. We further manipulated top-down and bottom-up processes in artificial seagrass through consumer reductions and nutrient additions, respectively. We indeed found that habitat isolation of seagrass patches decreased epibiont biomass and modified epibiont community composition. This pattern was largely due to dispersal limitation of invertebrate epibionts that resulted in a decline in their abundance and richness in isolated patches. Further, habitat isolation reduced consumer abundances, weakening top-down control of algal epibionts in isolated seagrass patches. Nutrient additions, however, reversed this pattern, and allowed a top-down effect on algal richness to emerge in isolated habitats, demonstrating a complex interaction between patch isolation and top-down and bottom-up processes. Habitat isolation may therefore shape the relative importance of central processes in ecosystems, leading to changes in community composition and food web structure in marine habitats.
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Govers, Laura L., Jannes H. T. Heusinkveld, Max L. E. Gräfnings, Quirin Smeele, and Tjisse van der Heide. "Adaptive intertidal seed-based seagrass restoration in the Dutch Wadden Sea." PLOS ONE 17, no. 2 (February 9, 2022): e0262845. http://dx.doi.org/10.1371/journal.pone.0262845.
Abstract:
Seagrasses form the foundation of many coastal ecosystems but are rapidly declining on a global scale. The Dutch Wadden Sea once supported extensive subtidal seagrass meadows that have all disappeared. Here, we report on the setbacks and successes of intertidal seed-based restoration experiments in the Dutch Wadden Sea between 2014–2017. Our main goals were to 1) optimize plant densities, and 2) reduce seed losses. To achieve our goals, we conducted research-based, adaptive seagrass (Zostera marina) restoration, adjusting methods yearly based on previous results. We applied various seeding methods in three subsequent years–from Buoy Deployed Seeding (BuDS), and ‘BuDS-in-frame’ in fall, to a newly developed ‘Dispenser Injection Seeding’ (DIS) method. Our adaptive experimental approach revealed high seed losses between seeding and seedling establishment of the BuDS methods (>99.9%), which we mitigated by controlled harvest and storage of seeds throughout fall and winter, followed by DIS-seeding in spring. These iterative innovations resulted in 83 times higher plant densities in the field (0.012 to 1.00 plants m-2) and a small reduction in seed loss (99.94 to 99.75%) between 2015–2017. Although these developments have not yet resulted in self-sustaining seagrass populations, we are one step closer towards upscaling seagrass restoration in the Dutch Wadden Sea. Our outcomes suggest that an iterative, research-based restoration approach that focuses on technological advancement of precision-seeding may result in advancing knowledge and improved seed-based seagrass restoration successes.
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Karlina, Ita, Aditya Hikmat Nugraha, Dony Apdillah, Jelita Rahma Hidayati, and Esty Kurniawati. "Sosialisasi penyemaian bibit dari buah Enhalus acoroides untuk menjaga keberlanjutan ekosistem Lamun di Desa Pengudang Pulau Bintan." Unri Conference Series: Community Engagement 3 (November 18, 2021): 148–55. http://dx.doi.org/10.31258/unricsce.3.148-155.
Abstract:
Seagrass ecosystems contribute to food security, climate change mitigation, and biodiversity, yet they are vulnerable to changes in the environment. Environmental factors, both natural and human-caused, are the primary cause of the loss in the area of seagrass ecosystems. Transplanting or sowing seagrass is one method for addressing this issue. The goal of this project is to maintain the seagrass environment and give coastal people with knowledge so that they may contribute to the conservation of coastal habitats, particularly seagrass ecosystems, in Pengudang Village, Bintan. The seeding process starts with a search for seagrass in areas with a dense seagrass habitat. Enhalus acoroides was chosen as the seeding object in this investigation. The findings revealed that 78% of respondents were highly aware of the existence of seagrass ecosystems (perception), 28% were very aware of the function and existence of seagrass ecosystems (understanding), and 86% significantly participated in seagrass ecosystem conservation (participation).
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Unsworth, Richard K. F., Leanne C. Cullen-Unsworth, James N. Hope, Benjamin L. H. Jones, Richard J. Lilley, Hanna K. Nuuttila, Beth Williams, and Nicole E. Esteban. "Effectiveness of Moorings Constructed from Rope in Reducing Impacts to Seagrass." Oceans 3, no. 3 (August 31, 2022): 431–38. http://dx.doi.org/10.3390/oceans3030029.
Abstract:
Seagrass meadows commonly reside in shallow sheltered coastal environments which are typically safe havens for mooring boats. There is evidence from around the globe that the use of common swinging chain moorings leads to halos of bare sediment in otherwise productive seagrass. These halos reduce animal abundance and diversity and lead to a loss of the carbon stored within sediments. To protect and enhance seagrass ecosystem services, low-cost simple solutions are required that can solve the problems of boating-based disturbance. In the present novel study, we provide evidence that the simple replacement of mooring chains with rope can significantly reduce damage to sensitive benthic habitats such as seagrass. At three locations across a range of environmental conditions, we provide evidence that well-established moorings constructed from rope do not damage seagrass. Overall, there was a significant effect (F1,756 = 299.46, p < 0.001) of the mooring type and distance from the mooring base. This equates to a 44% increase in seagrass cover within areas around a rope mooring relative to a chain one. Most small boat mooring activity happens within the summer months, therefore large heavy-duty winter mooring systems are not required in many situations, opening opportunities for adapted systems that have a reduced environmental impact. The present study suggests that there is a ready-made, low-technology, low-cost solution already in existence for halting the widespread loss of seagrass from small boat mooring damage and allowing recovery and opportunity for restoration.
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Tol, Samantha J., Rob G. Coles, and Bradley C. Congdon. "Dugong dugonfeeding in tropical Australian seagrass meadows: implications for conservation planning." PeerJ 4 (July 7, 2016): e2194. http://dx.doi.org/10.7717/peerj.2194.
Abstract:
Dugongs (Dugong dugon) are listed as vulnerable to extinction due to rapid population reductions caused in part by loss of seagrass feeding meadows. Understanding dugong feeding behaviour in tropical Australia, where the majority of dugongs live, will assist conservation strategies. We examined whether feeding patterns in intertidal seagrass meadows in tropical north-eastern Australia were related to seagrass biomass, species composition and/or nitrogen content. The total biomass of each seagrass species removed by feeding dugongs was measured and compared to its relative availability. Nitrogen concentrations were also determined for each seagrass species present at the sites. Dugongs consumed seagrass species in proportion to their availability, with biomass being the primary determining factor. Species composition and/or nitrogen content influenced consumption to a lesser degree. Conservation plans focused on protecting high biomass intertidal seagrass meadows are likely to be most effective at ensuring the survival of dugong in tropical north-eastern Australia.
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Dolbeth, Marina, Dimítri de Araújo Costa, Manuel Meyer, José Alberto Gonçalves, and Ana Bio. "Characterisation and Dynamics of an Emerging Seagrass Meadow." Remote Sensing 15, no. 16 (August 19, 2023): 4086. http://dx.doi.org/10.3390/rs15164086.
Abstract:
Seagrasses are habitat-forming species that support biodiversity and a wide range of associated ecosystem services, from blue carbon capture to providing nursery areas for a variety of organisms. Their decline has been documented worldwide and is attributed to human impacts ranging from habitat loss and eutrophication to the effects of climate change. However, recent recovery trends have also been documented due to reductions in stressors, passive and active restoration, and even changes in environmental conditions owing to local management. In this study, we document for the first time the occurrence of Zostera noltei in the downstream area of the River Minho Estuary. This occurrence was unexpected given the hydrological conditions of the estuary, characterised by dredging and siltation. We reconstructed the occurrence and historical distribution of seagrass beds, and showed that they have existed in the region for more than a decade. The current distribution area was mapped using high-resolution multispectral remote sensing techniques, and in situ photoquadrats to complement the remote sensing information with an evaluation of the seagrass cover. A current seagrass area of 0.81 ha was found with an average cover of 70%. However, the Minho Estuary continues to be strongly affected by sediment deposition, which may affect the seagrass population in the long term. Continued surveys are recommended to confirm the long-term trend of colonisation of this important habitat, which ultimately provides so many benefits to coastal ecosystems and humankind.
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Creed, Joel C., Laura Sol Aranda, Júlia Gomes de Sousa, Caio Barros Brito do Bem, Beatriz Sant’Anna Vasconcelos Marafiga Dutra, Marianna Lanari, Virgínia Eduarda de Sousa, et al. "A Synthesis of Provision and Impact in Seagrass Ecosystem Services in the Brazilian Southwest Atlantic." Sustainability 15, no. 20 (October 11, 2023): 14722. http://dx.doi.org/10.3390/su152014722.
Abstract:
The ongoing environmental crisis, driven by biodiversity loss and climate change, raises concerns about the impacts on marine systems and human well-being. These environments provide crucial ecosystem services valued at approximately USD 74.5 trillion·year−1 globally. Seagrasses support fisheries, protect coasts, help mitigate climate change, maintain biodiversity, provide food security, and enhance water quality. However, comprehensive assessments of seagrass ecosystem services (SESs) and their impacts are lacking. Focusing on the Brazilian southwest Atlantic, our aim is to bridge this gap and identify key research areas for improved management decisions. Our literature search employed n = 19 paired terms for seagrass in Brazil. We screened 30,351 search returns for 394 relevant documents. Research on SESs has grown over time, and most research has focused on provisioning and supporting ecosystem services: 79.7% of documents mentioned at least one SES, while 24.5% of the documents provided evidence of observed SESs; 31.5% only provided information on expected SESs. Provisioning services were the most observed and expected. Coastal urbanization (54%) and marine food provisioning (17%) were the main drivers impacting SESs. Terrestrial food and material provision (9%) and climate change (8%) were also significant drivers. This study provides key recommendations aimed at fostering further research and management strategies to consider the complete ensemble of ecosystem services for a range of seagrass bioregions, to better understand the provision of and impacts to seagrass services and human well-being at the global scale.
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Gunawan, Jessica Viny, Maxi Parengkuan, A'an Johan Wahyudi, and Firman Zulpikar. "Estimasi Stok Karbon pada Biomassa Lamun di Pulau Semak Daun, Kepulauan Seribu." Oseanologi dan Limnologi di Indonesia 4, no. 2 (August 31, 2019): 89. http://dx.doi.org/10.14203/oldi.2019.v4i2.229.
Abstract:
<strong>Carbon Stock Estimation in Seagrass Biomass on Semak Daun Island, Thousand Islands</strong>. Seagrass ecosystem has a vital role in protecting the coastal ecosystem. It can also sequester and store carbon as an organic material (blue carbon) for a long time. However, anthropogenic activities in coastal areas give environmental stress on the seagrass ecosystem. This research was conducted to assess the carbon stock of seagrass biomass in Semak Daun Island in order to evaluate the potential of the seagrass meadows in sequestering carbon. Sampling and observation were held in the seagrass ecosystem to obtain seagrass density, biomass, frequency of occurrence, water quality, and anthropogenic activity. Carbon stock was calculated by the loss of ignition (LOI) method, and combined with density to determine the total carbon stock in the whole area of seagrass meadows. Seagrass species in Semak Daun Island consist of Halophila ovalis, Thalassia hemprichii, Cymodocea rotundata, Syringodium isoetifolium, and Halodule uninervis. The coverage area of seagrass in Semak Daun Island was 9.1 ha with carbon stock value of 1.84 ton C or equivalent to 6.76 ton CO2. Fifty two percent of the carbon stock was originated from the below-ground biomass and 48% from the above-ground biomass.
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Thomson, A. C. G., S. M. Trevathan-Tackett, D. T. Maher, P. J. Ralph, and P. I. Macreadie. "Bioturbator-stimulated loss of seagrass sediment carbon stocks." Limnology and Oceanography 64, no. 1 (September 27, 2018): 342–56. http://dx.doi.org/10.1002/lno.11044.
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Wear, Rachel J., Jason E. Tanner, and Sonja L. Hoare. "Facilitating recruitment of Amphibolis as a novel approach to seagrass rehabilitation in hydrodynamically active waters." Marine and Freshwater Research 61, no. 10 (2010): 1123. http://dx.doi.org/10.1071/mf09314.
Abstract:
Worldwide, 29% of seagrass habitats have been lost over the past century. Compared with large-scale losses, successful restoration programs are usually only small scale (a few hectares). One area of significant seagrass loss (>5200 ha) is Adelaide, South Australia. Improvements to wastewater management have raised the possibility of rehabilitation in this area. Traditional methods of seagrass restoration are expensive and have had limited success owing to high wave energy. We investigated a range of biodegradable substrates, mostly made of hessian (burlap), to enhance Amphibolis recruitment as an alternative. After 5 weeks, 16 514 seedlings, or 157 seedlings m–2, had recruited. Survival declined over the following 12 months to 31.4%, and down to 7.2% after 3 years, in part as a result of breakdown of the hessian, and the wave-exposed nature of the sites. During the initial 12 months, above- and belowground biomass increased 2.6- and 6.4-fold, respectively. The technique may represent a non-destructive, cost-effective (<AU$10 000 ha–1) method to restore Amphibolis over large spatial scales and in areas that are hydrodynamically too active for traditional techniques, thus helping ameliorate some of the large-scale losses of seagrasses that have occurred globally.
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French, Emily, Ashley R. Smyth, Laura K. Reynolds, and Kenneth A. Moore. "Nitrogen Cycling in Widgeongrass and Eelgrass Beds in the Lower Chesapeake Bay." Nitrogen 5, no. 2 (April 18, 2024): 315–28. http://dx.doi.org/10.3390/nitrogen5020021.
Abstract:
Eelgrass (Zostera marina) loss occurs worldwide due to increasing water temperatures and decreasing water quality. In the U.S., widgeongrass (Ruppia maritima), a more heat-tolerant seagrass species, is replacing eelgrass in certain areas. Seagrasses enhance sediment denitrification, which helps to mitigate excess nitrogen in coastal systems. Widgeongrass and eelgrass have different characteristics, which may affect sediment nitrogen cycling. We compared net N2 fluxes from vegetated areas (eelgrass and widgeongrass beds, using intact cores that included sediment and plants) and adjacent unvegetated areas from the York River, in the lower Chesapeake Bay during the spring and summer of one year. We found that seagrass biomass, sediment organic matter, and NH4+ fluxes were significantly higher in eelgrass beds than in widgeongrass beds. Eelgrass was also net denitrifying during both seasons, while widgeongrass was only net denitrifying in the summer. Despite differences in the spring, the seagrass beds had a similar rate of N2 production in the summer and both had higher denitrification rates than unvegetated sediments. Both species are important ecosystem components that can help to mitigate eutrophication in coastal areas. However, as the relative composition of these species continues to change, differences in sediment nitrogen cycling may affect regional denitrification capacity.
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Vo, Trong-Thach, Khin Lau, Lawrence M. Liao, and Xuan-Vy Nguyen. "Satellite image analysis reveals changes in seagrass beds at Van Phong Bay, Vietnam during the last 30 years." Aquatic Living Resources 33 (2020): 4. http://dx.doi.org/10.1051/alr/2020005.
Abstract:
Seagrass meadows are fragile ecosystems in the coastal zone. Natural disasters, land reclamation and various human activities seem to exert negative impacts on the distribution and biological performance of seagrass beds in Vietnam. In this present study, satellite Landsat TM/OLI image analysis was applied to determine changes in seagrass distribution at Van Phong Bay, Vietnam in the last 30 years. The maximum likelihood decision rule was used to extract seagrass bed distribution data. The error matrix using the in situ reference data for HLM image classification was 81–95% accurate, and Kappa coefficients were between 0.72 and 0.91. The results indicated that 186.2 ha (or 35.8%) of the original seagrass beds were lost in the last three decades at Van Phong Bay, and decline in each specific site may have been due to different causes. Typhoons may have caused the loss of seagrass beds at open-sea sites whereas aquaculture activities, excavation and terrigenous obliteration may have caused such losses in protected sites.
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Cambridge, M. L., A. W. Chiffings, C. Brittan, L. Moore, and A. J. McComb. "The loss of seagrass in Cockburn Sound, Western Australia. II. Possible causes of seagrass decline." Aquatic Botany 24, no. 3 (June 1986): 269–85. http://dx.doi.org/10.1016/0304-3770(86)90062-8.
40
Hendriks, I. E., Y. S. Olsen, L. Ramajo, L. Basso, A. Steckbauer, T. S. Moore, J. Howard, and C. M. Duarte. "Photosynthetic activity buffers ocean acidification in seagrass meadows." Biogeosciences 11, no. 2 (January 28, 2014): 333–46. http://dx.doi.org/10.5194/bg-11-333-2014.
Abstract:
Abstract. Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range ΩAr. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min ΩAr, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range ΩAr within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, ΩAr and carbonate deposition. Calcifying organisms, e.g. epiphytes with carbonate skeletons, may benefit from the modification of the carbonate system by the meadow. There is, however, concern for the ability of seagrasses to provide modifications of similar importance in the future. The predicted decline of seagrass meadows may alter the scope for alteration of pH within a seagrass meadow and in the water column above the meadow, particularly if shoot density and biomass decline, on which LAI is based. Organisms associated with seagrass communities may therefore suffer from the loss of pH buffering capacity in degraded meadows.
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Baeti, Tiara Nur Baeti, Retno Hartati Hartati, and Ita Riniatsih Riniatsih. "Potensi Simpanan Karbon Pada Lamun Cymodocea serrulata Di Pantai Prawean, Jepara." Journal of Marine Research 8, no. 1 (February 3, 2019): 19–26. http://dx.doi.org/10.14710/jmr.v8i1.24322.
Abstract:
Pemanasan global merupakan akibat dari peningkatan gas-gas rumah kaca (GRK), seperti halnya gas karbondioksida, metana, nitro dioksida, maupun gas alam lainnya. Ekosistem padang lamun di perairan Pantai Prawean, Kabupaten Jepara memiliki fungsi ekologis yang sangat penting sebagai penyangga ekosistem lain di perairan tersebut. Potensi padang lamun diantaraanya adalah sebagai penyimpan emisi karbon, sehingga mampu mencegah terjadinya pemanasan global (global warming) atau biasa disebut sebagai blue carbon. Tujuan penelitian ini adalah untuk menentukan potensi simpanan karbon pada lamun jenis Cymodocea serrulata di perairan Pantai Prawean, Kabupaten Jepara. Penelitian ini dilakukan pada bulan Desember 2018 dan Maret 2019 dengan metode pengukuran karbon pada lamun Loss of Ignition (LOI). Hasil penelitian menunjukkan bahwa biomassa terbesar terletak pada bagian Below Ground (akar dan rhizoma) dengan persentase di atas 50% pada kedua waktu pengamatan bila dibandingkan dengan jaringan lamun di atas substrat (daun). Rata-rata kandungan karbon tertinggi pada kedua waktu penelitain terletak pada bagian akar lamun dengan persentase nilai simpanan karbon mencapai 55 – 57%. Terjadi penurunan nilai simpanan karbon dalam dua kali pengambilan data, yakni pada bulan Desember 2018 total simpanan karbon pada lamun Cymodocea serrulata mencapai 6,77 ton sedangkan pada bulan Maret 2019 nilainya turun menjadi 5,38 ton. Penurunan total simpanan karbon pada lamun ini di duga diakibatkan oleh adanya perubahan faktor fisik perairan serta adanya faktor antropogenik di wilayah perairan tersebut.Global warming is a result of increasing greenhouse gases (GHG), such as carbon dioxide, methane, nitrous dioxide, and other natural gas. Seagrass ecosystems in the waters of Prawean Beach, Jepara Regency have very important ecological functions as a buffer for other ecosystems in these waters. The potential of seagrass bed is as a store of carbon emissions, so as to prevent global warming or commonly referred to as blue carbon. The purpose of this research is to determine the potention of carbon deposits in seagrass species of Cymodocea serrulata in the waters of Prawean Beach, Jepara Regency. This research was conducted in December 2018 and March 2019 with the method of carbon measurement in seagrass Loss of Ignition (LOI). The results showed that the largest biomass was located in the Below Ground (roots and rhizomes) with a percentage above 50% at both observation time when compared to seagrass tissue on the substrate (leaves). The highest average carbon content at both time of the survey was located in the seagrass root section with a percentage of the value of carbon deposits reaching 55 - 57%. There was a decrease in the value of carbon deposits in two data collection, namely in December 2018 the total carbon deposits in seagrass Cymodocea serrulata reached 6,77 tons while in March 2019 the value dropped to 5,38 tons. The decrease in total carbon deposits in seagrasses is thought to be caused by changes in physical factors of the waters and the presence of anthropogenic factors in these waters.
42
Yamamuro, M., I. Koike, and H. Iizumi. "Partitioning of the nitrogen stock in the vicinity of a Fijian seagrass bed dominated by Syringodium isoetifolium (Ascherson) Dandy." Marine and Freshwater Research 44, no. 1 (1993): 101. http://dx.doi.org/10.1071/mf9930101.
Abstract:
Partitioning of the nitrogen stock in a Fijian seagrass bed dominated by Syringodium isoetifolium (Ascherson) Dandy and in an adjacent area bare of macrophytic vegetation was assessed to evaluate the effect of the presence of seagrass on coral sediment. Concentrations of major nutrients, such as nitrogen and phosphate, were as low in the water column at the seagrass bed and the bare area as they were in the open ocean. Concentrations of ammonium and dissolved organic nitrogen, however, were higher in the water within the seagrass canopy than they were in other waters. In sediments at the seagrass bed and the bare area, interstitial nitrogen, such as nitrate and dissolved organic nitrogen, was a minor component of the total nitrogen (0.3-0.05%). On the other hand, concentrations of total organic nitrogen in seagrass-bed sediment (about 70% of which was in the form of amorphous organic nitrogen and the rest of which came from living and dead seagrass) were more than three times higher than those in bare-area sediment. Concentrations of organic carbon from amorphous organic materials in seagrass-bed sediment showed no large change with depth, resulting in an apparent decrease in the carbodnitrogen atom ratio from 60 to 10. These results suggest some mechanisms to minimize the loss of nitrogen stock from the sediment of tropical seagrass beds.
43
Morris, Liz, Gregory Jenkins, David Hatton, and Timothy Smith. "Effects of nutrient additions on intertidal seagrass (Zostera muelleri) habitat in Western Port, Victoria, Australia." Marine and Freshwater Research 58, no. 7 (2007): 666. http://dx.doi.org/10.1071/mf06095.
Abstract:
Loss of seagrass habitat in many parts of the world has been attributed to increases in nutrient loading to nearshore areas. The role of excess epiphyte, macroalgal or phytoplankton growth in shading of seagrass leaves and negatively affecting seagrass health is generally agreed to be a prevalent mechanism in seagrass decline worldwide. In the present study nutrient addition experiments were undertaken at three sites in Western Port, Victoria. Nutrients were added to the water column using the controlled release fertiliser Osmocote™ in late summer 2005. The experiments ran for one month at two of the sites (Blind Bight and Hastings) and at the third site (Crib Point) the experiment ran for three months. Control and nutrient addition plots were monitored for concentrations of inorganic nutrients, number of seagrass leaves, seagrass, epiphyte and loose algal biomass and invertebrate faunal assemblages. Nutrient additions had increased ash free dry weight of seagrass leaves and loose algae at two of the three sites studied. There was also an increase in gammarid amphipod densities at the Crib Point site. We consider that Western Port seagrass habitat is sensitive to increased loads of nutrients within the water column with the Blind Bight region most at risk.
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Endarwantti, Vionita, Ali Djunaedi, and Gunawan Widi Santosa. "Estimasi Simpanan Karbon dan Bioekologi Lamun di Pantai Prawean, Jepara." Journal of Marine Research 12, no. 4 (September 25, 2023): 579–85. http://dx.doi.org/10.14710/jmr.v12i4.35699.
Abstract:
Perubahan iklim global yang semakin meningkat dapat menyebabkan kenaikan kadar karbondioksida pada atmosfer. Lamun dapat mengurangi kadar karbondioksida pada atmosfer dengan cara menyerap karbon anorganik melalui proses fotosintesis lamun dan menyimpannya dalam bentuk karbon organik dalam jangka waktu lama. Oleh karena itu penelitian ini bertujuan untuk mengetahui komposisi jenis, kerapatan, penutupan, indeks ekologi, biomassa, dan karbon pada vegetasi lamun di Pantai Prawean, Jepara. Penelitian ini menggunakan metode pengambilan data secara purposive sampling. Pendataan kondisi padang lamun mengacu pada metode LIPI 2014 dengan mendata penutupan, dan kerapatan lamun. Pengambilan sampel lamun menggunakan seagrass core secara acak. Sampel lamun diolah dengan metode Loss On Ignition (LOI) untuk mengetahui kadar karbon. Selanjutnya data kadar karbon dikonversikan berdasarkan nilai biomassa lamun. Jenis lamun yang ditemukan di Pantai Prawean berjumlah 5 jenis antara lain Cymodocea rotundata, Thalassia hemprichiii, Oceana serrulata, Enhalus acoroides dan Halodule uninervis. Kerapatan lamun di Pantai Prawean dapat mencapai 1717 individu/m2 pada stasiun 1 dan 780 individu/m2pada stasiun 2. Persentase penutupan lamun total di Pantai Prawean sebesar 39,20 % pada stasiun 1 dan 22,73 % pada stasiun 2. Indeks ekologi pada stasiun 1 memiliki keanekaragaman rendah, keseragaman rendah dan ada dominasi lamun. Sedangkan pada stasiun 2 memiliki keanekaragaman sedang, keseragaman sedang dan dominasi sedang. Total biomassa lamun pada stasiun 1 dan stasiun 2 sebesar 2970,01 g/m2 dan 1345,85 g/m2. Total estimasi kandungan karbon lamun pada stasiun 1 dan stasiun 2 sebesar 1000,61 gC/m2 dan 447,27 gC/m2. Global climate change can cause an increase in carbon dioxide levels in the atmosphere. Seagrass can reduce carbon dioxide levels in the atmosphere by absorbing inorganic carbon through the seagrass photosynthesis process and storing it in the form of organic carbon for a long time. Therefore, this study was conducted to determine species composition, density, cover, ecological index, biomass, and carbon in seagrass vegetation in Prawean Beach, Jepara. This research uses purposive sampling data collection method. Data collection on the condition of seagrass beds refers to the 2014 LIPI method by recording the cover and density of seagrass. Seagrass sampling used random seagrass cores. Seagrass samples were processed by the Loss On Ignition (LOI) method to determine the carbon content. Furthermore, the carbon content data is converted based on the value of seagrass biomass. There are 5 types of seagrass found on Prawean Beach, namely Cymodocea rotundata, Thalassia hemprichiii, Oceana serrulata, Enhalus acoroides and Halodule uninervis. The density of seagrass in Prawean Beach can reach 1717 individuals/m2 at station 1 and 780 individuals/m2 at station 2. The percentage of total seagrass cover in Prawean Beach is 39.20% at station 1 and 22.73% at station 2. station 1 has low diversity, low uniformity and there is a dominance of seagrass. While at station 2 has moderate diversity, moderate uniformity and moderate dominance. The total biomass of seagrass at station 1 and station 2 was 2970.01 g/m2 and 1345.85 g/m2. The total estimated carbon content of seagrass at station 1 and station 2 is 1000.61 gC/m2 and 447.27 gC/m2.
45
Persson, Carl. "Nature-Based Nutrient Reduction for Seagrass Restoration." Marine Technology Society Journal 55, no. 3 (May 1, 2021): 112–13. http://dx.doi.org/10.4031/mtsj.55.3.38.
Abstract:
Abstract Seagrasses provide the following benefits worldwide. <list list-type="bullet"><list-item>Habitat for Marine Life</list-item><list-item>Nursery for Juvenile Fish</list-item><list-item>Food</list-item><list-item>Biodiversity</list-item><list-item>Carbon Storage (Blue Carbon)</list-item><list-item>Ocean Acidification Control</list-item><list-item>Oxygen Production</list-item><list-item>Sediment Erosion Control</list-item><list-item>Nutrient Cycling</list-item></list> Seagrass loss has been persistent for the past 100 years and is now accelerating at 7 percent (21,000 square kilometers) per year. We are addressing seagrass loss resulting from nutrient pollution which is about one third of the total.The technical objective is to remove at least as much total nitrogen from the sediment and bottom waters to allow restoration with the subsequent successful planting of seeds from nearby meadows.Our nature-based process starts with the eutrophication-induced restriction on the process to remove excess nitrogen from the top layer of sediment, coupled nitrification denitrification (CND). Decaying organic matter and biogeochemical processes consume enough oxygen to reduce the efficiency and capacity of the CND process.The solution is to increase the rate of dissolved oxygen flux in the bottom waters. Although science has known this for 20 years, how to do it has been a mystery. To facilitate oxygen dissolution, we will use nanoscale oxygen bubbles mixed with bottom water and delivered to the water/sediment interface.
46
Chand, Subhash, and Barbara Bollard. "Detecting the Spatial Variability of Seagrass Meadows and Their Consequences on Associated Macrofauna Benthic Activity Using Novel Drone Technology." Remote Sensing 14, no. 1 (December 30, 2021): 160. http://dx.doi.org/10.3390/rs14010160.
Abstract:
Seagrass meadows are undergoing significant decline locally and globally from human and climatic impacts. Seagrass decline also impacts seagrass-dependent macrofauna benthic activity, interrupts their vital linkage with adjacent habitats, and creates broader degradation through the ecosystem. Seagrass variability (gain and loss) is a driver of marine species diversity. Still, our understanding of macrofauna benthic activity distribution and their response to seagrass variability from remotely sensed drone imagery is limited. Hence, it is critical to develop fine-scale seasonal change detection techniques appropriate to the scale of variability that will apply to dynamic marine environments. Therefore, this research tested the performance of the VIS and VIS+NIR sensors from proximal low altitude remotely piloted aircraft system (RPAS) to detect fine-scale seasonal seagrass variability using spectral indices and a supervised machine learning classification technique. Furthermore, this research also attempted to identify and quantify macrofauna benthic activity from their feeding burrows and their response to seagrass variability. The results from VIS (visible spectrum) and VIS+NIR (visible and near-infrared spectrum) sensors produced a 90–98% classification accuracy. This accuracy established that the spectral indices were fundamental in this study to identify and classify seagrass density. The other important finding revealed that seagrass-associated macrofauna benthic activity showed increased or decreased abundance and distribution with seasonal seagrass variability from drone high spatial resolution orthomosaics. These results are important for seagrass conservation because managers can quickly detect fine-scale seasonal changes and take mitigation actions before the decline of this keystone species affects the entire ecosystem. Moreover, proximal low-altitude, remotely sensed time-series seasonal data provided valuable contributions for documenting spatial ecological seasonal change in this dynamic marine environment.
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Nurafni, Iswandi Wahab, Balgis Bachmid, Rinto M. Nur, Kismanto Koroy, Djainudin Alwi, Titien Sofiati, and Any Kurniawati. "Carbon Absorption Potential on Seagrass Types Enhalus acoroides and Thalassia hemprichii In Morotai Island Water." International Journal of Research in Vocational Studies (IJRVOCAS) 2, no. 3 (December 16, 2022): 24–30. http://dx.doi.org/10.53893/ijrvocas.v2i3.137.
Abstract:
Seagrass is one of the most important ecosystems in coastal areas. Seagrass beds can absorb carbon of 1.15 tons/ha, with a carbon content below the substrate of 0.88 tons/ha (76.3%), higher than the carbon above the substrate, which is only 0.27 tons/ha (23, 7%). Research on carbon absorption in seagrass is still relatively carried out, so it is necessary to research the potential for carbon absorption in seagrass types Enhalus acoroides and Thalassia hemprichii in Morotai waters. The research will be carried out from September to December 2021, starting with seagrass sampling in three sub-districts (South Morotai, East Morotai, and South West Morotai Districts). The types of seagrass used were Enhalus acoroides and Thalassia hemprichii. Biomass sample analysis was carried out at the Basic Laboratory of the Faculty of Fisheries and Marine Sciences, Pacific Morotai University. Carbon analysis on seagrass was carried out at the Chemical Oceanography Laboratory of the Faculty of Marine and Fisheries Sciences, Hasanudin University Makassar. The seagrass sampling method used the quadratic transect method and sample analysis using the method Loss On Ignition (LOI). The results showed that Thalassia hemprichii has the highest carbon content in the roots, with a value of 38.94 gC/m2 to 49.48 gC/m2. In contrast, Enhalus acoroides has the highest carbon content in the roots with a carbon value of 30.77 gC/m2 to 37.86 gC/m2.
48
Han, Qiuying, Chongyu Qiu, Wenxuan Zeng, Shiquan Chen, Muqiu Zhao, Yunfeng Shi, and Xiaoli Zhang. "Sediment Carbon Sequestration and Driving Factors in Seagrass Beds from Hainan Island and the Xisha Islands." Processes 11, no. 2 (February 2, 2023): 456. http://dx.doi.org/10.3390/pr11020456.
Abstract:
Seagrass beds are considered to be substantial sinks of “blue carbon”. However, differentiation in the carbon sink capacities of seagrass beds in different regions with distinct nutrient conditions remains unclear. In this study, sediment carbon stocks, seagrass biomass, and microbial community structures and potential functions of seagrass beds in eutrophic seawater adjacent to Hainan Island and oligotrophic seawater around the Xisha Islands were compared. Our results showed that sediment mineralizable organic carbon and dry bulk density were substantially higher on Hainan Island than on the Xisha Islands (t-test, p < 0.05), while sediment carbon stocks and the total organic carbon were comparable between the two regions (p > 0.05). Similarly, seagrass biomass was much higher on Hainan Island (p < 0.05). Sediment carbon stocks positively correlated with sediment nitrogen and negatively correlated to sediment pH and grain size (p < 0.05). Bacterial diversities were similar in the two regions, while fungi were more diverse on Hainan Island (p < 0.05). Proteobacteria, Desulfobacterota, Ascomycota and Basidiomycota could account for degrading organic carbon on Hainan Island. Proteobacteria and Bacteroidota may contribute primarily to carbon loss in the seagrass beds of the Xisha Islands. This study strengthens our understanding of the effects of human activities on carbon sequestration in seagrass bed ecosystems.
49
Marbà, Núria, Elena Díaz-Almela, and Carlos M. Duarte. "Mediterranean seagrass (Posidonia oceanica) loss between 1842 and 2009." Biological Conservation 176 (August 2014): 183–90. http://dx.doi.org/10.1016/j.biocon.2014.05.024.
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Wilson, K. G., and P. J. Ralph. "A COMPARISON OF THE EFFECTS OF TAPIS CRUDE OIL AND DISPERSED CRUDE OIL ON SUBTIDAL ZOSTERA CAPRICORNI." International Oil Spill Conference Proceedings 2008, no. 1 (May 1, 2008): 859–64. http://dx.doi.org/10.7901/2169-3358-2008-1-859.
Abstract:
ABSTRACT Oil spill mitigation managers need to know the effects of chemical dispersants on subtidal seagrass in order to determine the least net environmental impact of their actions. The decision-making process for chemical dispersant use in Australia, known as Net Environmental Benefit Analysis, is compromised in near shore areas due to a lack of information on dispersed oil impacts on subtidal seagrasses. This study aimed to determine the toxic effects of crude oil, dispersed and non-dispersed, on subtidal seagrass and to quantify the exposure amount. Zostera capricorni plants were exposed to a range of concentrations of different oil and dispersant combinations in the field. ?hotosynthetic health was measured using Pulse Amplitude Modulated (PAM) fluorometry and chlorophyll pigment analysis. Oil concentration was calculated in relative oil units using Ultraviolet Fluoresence (UVF) spectrophotometry. Limited photo synthetic impact was detected in Z. capricorni exposed to the water soluble fraction of the non-dispersed Tapis crude oil treatments. No significant photo synthetic impact was evident in the dispersed Tapis crude oil treatment even though the Total Petroleum Hydrocarbon (TPH) concentration in these treatments was higher than in the non-dispersed Tapis crude oil treatments. Plants from both treatments recovered following replenishment from the surrounding seawater. A substantial reduction of the total petroleum hydrocarbons within the mesoscosms over the 10 hour exposure period was evident and would likely suggest a rapid loss of the toxic mixture to the sediments rather than assimilation by the seagrass.