scholarly journals Net heterotrophy and carbonate dissolution in two subtropical seagrass meadows

2019 ◽  
Author(s):  
Bryce R. Van Dam ◽  
Christian Lopes ◽  
Christopher L. Osburn ◽  
James W. Fourqurean
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Direct Determination ◽  
Carbonate Dissolution ◽  
Ph Buffering ◽  
Seagrass Meadows ◽  
Export Ratio ◽  
Diel Cycles ◽  
Budget Analysis ◽  
Seagrass Ecosystems ◽  
Net Heterotrophy

Abstract. The net ecosystem productivity (NEP) of two contrasting seagrass meadows within one of the largest seagrass ecosystems in the world, Florida Bay, was assessed using direct measurements over consecutive diel cycles. We report significant differences between NEP determined by dissolved inorganic carbon (NEPDIC) and by dissolved oxygen (NEPDO), likely driven by differences in air-water gas exchange and contrasting responses to variations in light intensity. In this first direct determination of NEPDIC in seagrasses, we found that both seagrass ecosystems were net heterotrophic, on average, despite large differences in seagrass net aboveground primary productivity. Net ecosystem calcification (NEC) was also negative, indicating that both sites were net dissolving of carbonate minerals. We suggest that a combination of carbonate dissolution and respiration in sediments exceeded seagrass primary production and calcification, supporting our negative NEP and NEC measurements. Furthermore, a simple budget analysis indicates that these two seagrass meadows have contrasting impacts on pH buffering of adjacent systems, due to variations in the TA : DIC export ratio. The results of this study highlight the need for better temporal resolution, as well as accurate carbonate chemistry accounting in future seagrass metabolism studies.

scholarly journals Net heterotrophy and carbonate dissolution in two subtropical seagrass meadows

2019 ◽  
Vol 16 (22) ◽  
pp. 4411-4428 ◽  
Author(s):  
Bryce R. Van Dam ◽  
Christian Lopes ◽  
Christopher L. Osburn ◽  
James W. Fourqurean
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Direct Determination ◽  
Florida Bay ◽  
Open Water ◽  
Carbonate Dissolution ◽  
Mixing Processes ◽  
Seagrass Meadows ◽  
Diel Cycles ◽  
Seagrass Ecosystems ◽  
The Impact

Abstract. The net ecosystem productivity (NEP) of two seagrass meadows within one of the largest seagrass ecosystems in the world, Florida Bay, was assessed using direct measurements over consecutive diel cycles during a short study in the fall of 2018. We report significant differences between NEP determined by dissolved inorganic carbon (NEPDIC) and by dissolved oxygen (NEPDO), likely driven by differences in air–water gas exchange and contrasting responses to variations in light intensity. We also acknowledge the impact of advective exchange on metabolic calculations of NEP and net ecosystem calcification (NEC) using the “open-water” approach and attempt to quantify this effect. In this first direct determination of NEPDIC in seagrass, we found that both seagrass ecosystems were net heterotrophic, on average, despite large differences in seagrass net above-ground primary productivity. NEC was also negative, indicating that both sites were net dissolving carbonate minerals. We suggest that a combination of carbonate dissolution and respiration in sediments exceeded seagrass primary production and calcification, supporting our negative NEP and NEC measurements. However, given the limited spatial (two sites) and temporal (8 d) extent of this study, our results may not be representative of Florida Bay as a whole and may be season-specific. The results of this study highlight the need for better temporal resolution, accurate carbonate chemistry accounting, and an improved understanding of physical mixing processes in future seagrass metabolism studies.

Seagrass Ecosystems of Andaman and Nicobar Islands: Status and Future Perspective

2020 ◽  
Vol 7 (4) ◽  
pp. 169-174
Author(s):  
Chatragadda Ramesh ◽  
Raju Mohanraju
Keyword(s):  
Water Quality ◽  
Primary Production ◽  
Environmental Changes ◽  
Future Perspective ◽  
Marine Biodiversity ◽  
Seagrass Beds ◽  
Seagrass Meadows ◽  
Seagrass Ecosystem ◽  
Seagrass Ecosystems ◽  
Nicobar Islands

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.

scholarly journals STRUKTUR KOMUNITAS IKAN PADA EKOSISTEM LAMUN DI PANTAI PUDING KABUPATEN BANGKA SELATAN

2018 ◽  
Vol 12 (2) ◽  
pp. 35-44
Author(s):  
Sania Prisilia ◽  
Wahyu Adi ◽  
Arief Febrianto
Keyword(s):  
Strong Relationship ◽  
Data Retrieval ◽  
Line Transect ◽  
Thalassia Hemprichii ◽  
Seagrass Meadows ◽  
Gill Net ◽  
Seagrass Ecosystems ◽  
Halodule Uninervis ◽  
Relationship Of ◽  
Seagrass Density

Seagrass beds have a variety of roles in fish life, which can be used as nurseries, as a place for feeding ground, and for areas to seek protection. This study aims to analyze the structure of fish communities and seagrass communities and analyze the relationship of fish abundance with seagrass ecosystems. This research was conducted in March 2018 on the beach of Puding Air Banten II, Pasir Putih Village, Tukak Sadai District, Bangka Selatan Regency. Line transect method for seagrass data collection and fish data retrieval using fixed gill nets (gill net). The results of the study found that the total number of individual fish as much as 409 ind / m2 consisted of 25 species. The highest abundance of fish found in Station I with Ambassis interrupta species as many as 241 ind / m2. There were six types of seagrass found on the coast of Puding, namely Enhalus acoroides, Thalassia hemprichii, Halodule uninervis, Halophila spinulosa, Halophila decipiens and Cymodocea serrulata. The highest seagrass density was found at Station I with the seagrass Halodule uninervis species of 2541 ind / m2. Correlation coefficient analysis shows that the abundance of fish with seagrass density has a significant value of 0.956 which is classified as having a very strong relationship. Fish have higher abundance with seagrass meadows which vegetate with mangroves

Carbon storage in seagrass ecosystems along the Andaman coast of Thailand

2018 ◽  
Vol 61 (5) ◽  
pp. 429-440 ◽  
Author(s):  
Milica Stankovic ◽  
Naruemon Tantipisanuh ◽  
Anchana Prathep
Keyword(s):  
Climate Change ◽  
Carbon Content ◽  
Carbon Storage ◽  
Significant Influence ◽  
West Coast ◽  
Human Disturbance ◽  
Total Carbon ◽  
The West ◽  
Seagrass Meadows ◽  
Seagrass Ecosystems

Abstract Seagrass ecosystems are important contributors to mitigation of climate change, since they are responsible for large carbon sinks. However, there is limited knowledge regarding the importance of variability of carbon storage in various ecosystems. In this study, we estimated carbon storage in several structurally different seagrass meadows along the west coast of Thailand and determined whether degree of exposure, human disturbance, and meadow type influenced carbon storage within these meadows. Carbon content within the living vegetation was on average 3±2.7 Mg ha−1, whilst average storage of carbon in the sediment was 122±35.3 Mg ha−1. Meadow type and disturbance had a significant influence on total carbon storage in the ecosystem, while the degree of exposure of the bay did not show great differences. Uniform meadows had a higher average total carbon storage than mixed meadows (133±36.2 and 110±41.3 Mg ha−1, respectively). Undisturbed meadows had a higher average total carbon storage than disturbed ones (140±36.5 and 103±34.8 Mg ha−1, respectively). The results obtained contribute to our understanding of carbon storage on an ecosystem scale and can provide a baseline for proper management, conservation, and climate change studies in the region.

scholarly journals Radiocarbon isotopic evidence for assimilation of atmospheric CO<sub>2</sub> by the seagrass <i>Zostera marina</i>

2015 ◽  
Vol 12 (20) ◽  
pp. 6251-6258 ◽  
Author(s):  
K. Watanabe ◽  
T. Kuwae
Keyword(s):  
Carbon Source ◽  
Zostera Marina ◽  
Inorganic Carbon ◽  
Aquatic Vegetation ◽  
Dissolved Inorganic Carbon ◽  
Isotope Analysis ◽  
Co2 Exchange ◽  
Atmospheric Co2 ◽  
Isotopic Signatures ◽  
Seagrass Meadows

Abstract. Submerged aquatic vegetation takes up water-column dissolved inorganic carbon (DIC) as a carbon source across its thin cuticle layer. It is expected that marine macrophytes also use atmospheric CO2 when exposed to air during low tide, although assimilation of atmospheric CO2 has never been quantitatively evaluated. Using the radiocarbon isotopic signatures (Δ14C) of the seagrass Zostera marina, DIC and particulate organic carbon (POC), we show quantitatively that Z. marina takes up and assimilates atmospheric modern CO2 in a shallow coastal ecosystem. The Δ14C values of the seagrass (−40 to −10 ‰) were significantly higher than those of aquatic DIC (−46 to −18 ‰), indicating that the seagrass uses a 14C-rich carbon source (atmospheric CO2, +17 ‰). A carbon-source mixing model indicated that the seagrass assimilated 0–40 % (mean, 17 %) of its inorganic carbon as atmospheric CO2. CO2 exchange between the air and the seagrass might be enhanced by the presence of a very thin film of water over the air-exposed leaves during low tide. Our radiocarbon isotope analysis, showing assimilation of atmospheric modern CO2 as an inorganic carbon source, improves our understanding of the role of seagrass meadows in coastal carbon dynamics.

Short-Term Spatial and Temporal Carbonate Chemistry Variability in Two Contrasting Seagrass Meadows: Implications for pH Buffering Capacities

2018 ◽  
Vol 41 (5) ◽  
pp. 1282-1296 ◽  
Author(s):  
Tyler Cyronak ◽  
Andreas J. Andersson ◽  
Sydney D’Angelo ◽  
Philip Bresnahan ◽  
Charles Davidson ◽  
...  
Keyword(s):  
Carbonate Chemistry ◽  
Short Term ◽  
Ph Buffering ◽  
Seagrass Meadows

scholarly journals Seagrass meadows as a globally significant carbonate reservoir

2015 ◽  
Vol 12 (16) ◽  
pp. 4993-5003 ◽  
Author(s):  
I. Mazarrasa ◽  
N. Marbà ◽  
C. E. Lovelock ◽  
O. Serrano ◽  
P. S. Lavery ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Carbonate Reservoir ◽  
Seagrass Meadows ◽  
Carbonate Concentration ◽  
Sedimentary Carbonate ◽  
Seagrass Ecosystems ◽  
The Mean ◽  
Global Carbon ◽  
Particulate Inorganic Carbon ◽  
Natural Way

Abstract. There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha−1, with an average of 654 ± 24 Mg PIC ha−1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha−1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m−2 yr−1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr−1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC and POC) stocks between vegetated and adjacent un-vegetated sediments.

scholarly journals Beyond burial: lateral exchange is a significant atmospheric carbon sink in mangrove forests

2018 ◽  
Vol 14 (7) ◽  
pp. 20180200 ◽  
Author(s):  
Damien T. Maher ◽  
Mitchell Call ◽  
Isaac R. Santos ◽  
Christian J. Sanders
Keyword(s):  
Organic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sink ◽  
Blue Carbon ◽  
Mangrove Forests ◽  
Carbon Framework ◽  
Sequestration Potential ◽  
Seagrass Ecosystems ◽  
Atmospheric Carbon

The blue carbon paradigm has evolved in recognition of the high carbon storage and sequestration potential of mangrove, saltmarsh and seagrass ecosystems. However, fluxes of the potent greenhouse gases CH 4 and N 2 O, and lateral export of carbon are often overlooked within the blue carbon framework. Here, we show that the export of dissolved inorganic carbon (DIC) and alkalinity is approximately 1.7 times higher than burial as a long-term carbon sink in a subtropical mangrove system. Fluxes of methane offset burial by approximately 6%, while the nitrous oxide sink was approximately 0.5% of burial. Export of dissolved organic carbon and particulate organic carbon to the coastal zone is also significant and combined may account for an atmospheric carbon sink similar to burial. Our results indicate that the export of DIC and alkalinity results in a long-term atmospheric carbon sink and should be incorporated into the blue carbon paradigm when assessing the role of these habitats in sequestering carbon and mitigating climate change.

Sign in / Sign up

Export Citation Format

Share Document