scholarly journals Seagrass community-level controls over organic carbon storage are constrained by geophysical attributes within meadows of Zanzibar, Tanzania

2017 ◽  
Author(s):  
E. Fay Belshe ◽  
Dieuwke Hoeijmakers ◽  
Natalia Herran ◽  
Matern Mtolera ◽  
Mirta Teichberg
Keyword(s):  
Organic Carbon ◽  
Carbon Storage ◽  
Plant Traits ◽  
Belowground Biomass ◽  
Shoot Density ◽  
Plant Litter ◽  
Coarse Grained ◽  
Seagrass Meadows ◽  
Seagrass Ecosystems ◽  
Sediment Carbon

Abstract. The aim of this work was to explore the feasibility of using seagrass functional traits to predict differences in sediment carbon storage. At 19 sites within highly diverse seagrass meadows of Zanzibar, Tanzania, species cover was estimated along with three community traits hypothesized to influence sediment carbon storage (amount of above and belowground biomass, seagrass tissue nitrogen content, and shoot density). We identified five distinct seagrass communities that had notable variations in key plant traits but these differences did not translate into differences is sediment organic carbon (OC) storage. Across all communities, sediment OC was very low (ranging from 0.15 % to 0.75 %) and there were no differences in OC storage among communities, which was considerably lower (33.97.7 Mg C ha−1) than the global average (194.220.2 Mg C ha−1) reported for other seagrass ecosystems. In spite of high seagrass diversity and clear zonation among plant communities, sediments in all communities were shallow (ranging from 19 to 78 cm) and composed of medium-coarse grained carbonate sand on top of carbonate rock. We propose that geophysical conditions of the sediment were not conducive to OC stabilization, and outweighed any variation in the quantity or quality of plant litter inputs, ultimately leading to low OC storage within all seagrass communities. This highlights the complexity of OC cycling in seagrass ecosystems and cautions against the use of plant traits as a proxy for OC storage across all seagrass ecosystems.

scholarly journals Seagrass community-level controls over organic carbon storage are constrained by geophysical attributes within meadows of Zanzibar, Tanzania

2018 ◽  
Vol 15 (14) ◽  
pp. 4609-4626 ◽  
Author(s):  
Elizabeth Fay Belshe ◽  
Dieuwke Hoeijmakers ◽  
Natalia Herran ◽  
Matern Mtolera ◽  
Mirta Teichberg
Keyword(s):  
Organic Carbon ◽  
Plant Traits ◽  
Sediment Cores ◽  
Belowground Biomass ◽  
Shoot Density ◽  
Seagrass Meadows ◽  
Seagrass Community ◽  
Seagrass Ecosystems ◽  
Organic Carbon Storage ◽  
Thalassodendron Ciliatum

Abstract. The aim of this work was to explore the feasibility of using plant functional traits to identify differences in sediment organic carbon (OC) storage within seagrass meadows. At 19 sites within three seagrass meadows in the coastal waters of Zanzibar, Tanzania, species cover was estimated along with three community traits hypothesized to influence sediment OC storage (above and belowground biomass, seagrass tissue nitrogen content, and shoot density). Sediments within four biogeographic zones (fore reef, reef flat, tidal channel, and seagrass meadow) of the landscape were characterized, and sediment cores were collected within seagrass meadows to quantify OC storage in the top 25 cm and top meter of the sediment. We identified five distinct seagrass communities that had notable differences in the plant traits, which were all residing within a thin veneer (ranging from 19 to 78 cm thick) of poorly sorted, medium to coarsely grained carbonate sands on top of carbonate rock. One community (B), dominated by Thalassodendron ciliatum, contained high amounts of above (972±74 g DW m−2) and belowground (682±392 g DW m−2) biomass composed of low-elemental-quality tissues (leaf C : N = 24.5; rhizome C : N = 97). While another community (C), dominated by small-bodied ephemeral seagrass species, had significantly higher shoot density (4178 shoots m−2). However, these traits did not translate into differences in sediment OC storage and across all communities the percentage of OC within sediments was similar and low (ranging from 0.15 % to 0.75 %), as was the estimated OC storage in the top 25 cm (14.1±2.2 Mg C ha−1) and top meter (33.9±7.7 Mg C ha−1) of sediment. These stock estimates are considerably lower than the global average (194.2±20.2 Mg C ha−1) reported for other seagrass ecosystems and are on the lower end of the range of estimates reported for the tropical Indo-Pacific bioregion (1.9 to 293 Mg C ha−1). The uniformly low OC storage across communities, despite large inputs of low-quality belowground tissues in community B, indicates that the geophysical conditions of the coarse, shallow sediments at our sites were not conducive to OC stabilization and outweighed any variation in the quantity or quality of seagrass litter inputs. These results add to a growing body of evidence showing that geophysical conditions of the sediment modulate the importance of plant traits in regards to retention of OC within blue carbon ecosystems and cautions against the use of plant traits as a proxy for sediment OC storage across all seagrass ecosystems.

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.

Ten years of conservation efforts enhance seagrass cover and carbon storage in Thailand

2018 ◽  
Vol 61 (5) ◽  
pp. 441-451 ◽  
Author(s):  
Ekkalak Rattanachot ◽  
Milica Stankovic ◽  
Supaphon Aongsara ◽  
Anchana Prathep
Keyword(s):  
Organic Carbon ◽  
Carbon Storage ◽  
Seagrass Meadow ◽  
Seagrass Meadows ◽  
Rate Of Increase ◽  
Southern Thailand ◽  
Seagrass Cover ◽  
Conservation Projects ◽  
Organic Carbon Storage ◽  
Total Coverage

Abstract Seagrasses are known as engineering ecosystems that play important roles in coastal environments. Globally, seagrass areas have been declining, and many conservation projects have been carried out to prevent further decline. The goal of this work was to determine how successful conservation efforts have been in a seagrass meadow at Koh Tha Rai in the Nakhon Si Thammarat Province of southern Thailand in terms of meadow extent, coverage and organic carbon storage. A study was conducted in 2017 and compared to a previous study from 2006 to determine the effects of the various conservation efforts devoted to this area. The results show that the total seagrass area increased by 0.7 ha with a rate of increase of approximately 0.06 ha year−1. The total coverage of seagrass increased by approximately 3 times. The organic carbon in existing seagrass meadows (2006) was 53.35 Mg ha−1, while growth was 32.34 Mg ha−1 in the areas of new seagrass. Moreover, the total organic carbon storage in the sediment increased by 26.86 MgC from 2006 to 2017 (from 211.60 MgC to 235.46 MgC). In conclusion, this study demonstrated the importance of successful conservation efforts in terms of increasing seagrass meadow areas, seagrass coverage and carbon storage within the meadow.

scholarly journals Environmental drivers of sediment carbon storage in temperate seagrass meadows

Hydrobiologia ◽  
2019 ◽  
Vol 847 (7) ◽  
pp. 1773-1792 ◽  
Author(s):  
Mariana do Amaral Camara Lima ◽  
Raymond D. Ward ◽  
Chris B. Joyce
Keyword(s):  
Carbon Storage ◽  
Environmental Drivers ◽  
Seagrass Meadows ◽  
Sediment Carbon

scholarly journals Seagrass Recovery Following Marine Heat Wave Influences Sediment Carbon Stocks

2021 ◽  
Vol 7 ◽  
Author(s):  
Lillian R. Aoki ◽  
Karen J. McGlathery ◽  
Patricia L. Wiberg ◽  
Matthew P. J. Oreska ◽  
Amelie C. Berger ◽  
...  
Keyword(s):  
Heat Wave ◽  
Heat Waves ◽  
Central Area ◽  
Shoot Density ◽  
Seagrass Meadows ◽  
C Stocks ◽  
Sediment Carbon ◽  
The Impact ◽  
Marine Heat Wave

Worldwide, seagrass meadows accumulate significant stocks of organic carbon (C), known as “blue” carbon, which can remain buried for decades to centuries. However, when seagrass meadows are disturbed, these C stocks may be remineralized, leading to significant CO2 emissions. Increasing ocean temperatures, and increasing frequency and severity of heat waves, threaten seagrass meadows and their sediment blue C. To date, no study has directly measured the impact of seagrass declines from high temperatures on sediment C stocks. Here, we use a long-term record of sediment C stocks from a 7-km2, restored eelgrass (Zostera marina) meadow to show that seagrass dieback following a single marine heat wave (MHW) led to significant losses of sediment C. Patterns of sediment C loss and re-accumulation lagged patterns of seagrass recovery. Sediment C losses were concentrated within the central area of the meadow, where sites experienced extreme shoot density declines of 90% during the MHW and net losses of 20% of sediment C over the following 3 years. However, this effect was not uniform; outer meadow sites showed little evidence of shoot declines during the MHW and had net increases of 60% of sediment C over the following 3 years. Overall, sites with higher seagrass recovery maintained 1.7x as much C compared to sites with lower recovery. Our study demonstrates that while seagrass blue C is vulnerable to MHWs, localization of seagrass loss can prevent meadow-wide C losses. Long-term (decadal and beyond) stability of seagrass blue C depends on seagrass resilience to short-term disturbance events.

scholarly journals Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?

2016 ◽  
Author(s):  
O. Serrano ◽  
P. S. Lavery ◽  
C. M. Duarte ◽  
G. A. Kendrick ◽  
A. Calafat ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Clay Content ◽  
Cost Effective ◽  
Blue Carbon ◽  
Organic Carbon Content ◽  
Terrestrial Organic Matter ◽  
Seagrass Meadows ◽  
Clay Concentration ◽  
Seagrass Ecosystems

Abstract. The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (Corg) content in terrestrial soils and marine sediments has been correlated with mud content (i.e. silt and clay), however, empirical tests of this theory are lacking for coastal vegetated ecosystems. Here, we compiled data (n = 1345) on the relationship between Corg and mud (i.e. silt and clay, particle sizes <63 μm) contents in seagrass ecosystems (79 cores) and adjacent bare sediments (21 cores) to address whether mud can be used to predict soil Corg content. We also combined these data with the δ13C signatures of the soil Corg to understand the sources of Corg stores. The results showed that mud is positively correlated with soil Corg content only when the contribution of seagrass-derived Corg to the sedimentary Corg pool is relatively low, such as in small and fast growing meadows of the genera Zostera, Halodule and Halophila, and in bare sediments adjacent to seagrass ecosystems. In large and long-living seagrass meadows of the genera Posidonia and Amphibolis there was a lack of, or poor relationship between mud and soil Corg content, related to a higher contribution of seagrass-derived Corg to the sedimentary Corg pool in these meadows. The relative high soil Corg contents with relatively low mud contents (i.e. mud-Corg saturation) together with significant allochthonous inputs of terrestrial organic matter could overall disrupt the correlation expected between soil Corg and mud contents. This study shows that mud (i.e. silt and clay content) is not a universal proxy for blue carbon content in seagrass ecosystems, and therefore should not be applied generally across all seagrass habitats. Mud content can only be used as a proxy to estimate soil Corg content for scaling up purposes when opportunistic and/or low biomass seagrass species (i.e. Zostera, Halodule and Halophila) are present (explaining 34 to 91% of variability), and in bare sediments (explaining 78% of the variability).

scholarly journals Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?

2016 ◽  
Vol 13 (17) ◽  
pp. 4915-4926 ◽  
Author(s):  
Oscar Serrano ◽  
Paul S. Lavery ◽  
Carlos M. Duarte ◽  
Gary A. Kendrick ◽  
Antoni Calafat ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Low Cost ◽  
Cost Effective ◽  
Scaling Up ◽  
Blue Carbon ◽  
Organic Carbon Content ◽  
Terrestrial Organic Matter ◽  
Seagrass Meadows ◽  
Seagrass Ecosystems

Abstract. The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (Corg) content in terrestrial soils and marine sediments has been correlated with mud content (i.e., silt and clay, particle sizes < 63 µm), however, empirical tests of this theory are lacking for coastal vegetated ecosystems. Here, we compiled data (n =  1345) on the relationship between Corg and mud contents in seagrass ecosystems (79 cores) and adjacent bare sediments (21 cores) to address whether mud can be used to predict soil Corg content. We also combined these data with the δ13C signatures of the soil Corg to understand the sources of Corg stores. The results showed that mud is positively correlated with soil Corg content only when the contribution of seagrass-derived Corg to the sedimentary Corg pool is relatively low, such as in small and fast-growing meadows of the genera Zostera, Halodule and Halophila, and in bare sediments adjacent to seagrass ecosystems. In large and long-living seagrass meadows of the genera Posidonia and Amphibolis there was a lack of, or poor relationship between mud and soil Corg content, related to a higher contribution of seagrass-derived Corg to the sedimentary Corg pool in these meadows. The relatively high soil Corg contents with relatively low mud contents (e.g., mud-Corg saturation) in bare sediments and Zostera, Halodule and Halophila meadows was related to significant allochthonous inputs of terrestrial organic matter, while higher contribution of seagrass detritus in Amphibolis and Posidonia meadows disrupted the correlation expected between soil Corg and mud contents. This study shows that mud is not a universal proxy for blue carbon content in seagrass ecosystems, and therefore should not be applied generally across all seagrass habitats. Mud content can only be used as a proxy to estimate soil Corg content for scaling up purposes when opportunistic and/or low biomass seagrass species (i.e., Zostera, Halodule and Halophila) are present (explaining 34 to 91 % of variability), and in bare sediments (explaining 78 % of the variability). The results obtained could enable robust scaling up exercises at a low cost as part of blue carbon stock assessments.

scholarly journals Contributions of the direct supply of belowground seagrass detritus and trapping of suspended organic matter to the sedimentary organic carbon stock in seagrass meadows

2018 ◽  
Vol 15 (13) ◽  
pp. 4033-4045 ◽  
Author(s):  
Toko Tanaya ◽  
Kenta Watanabe ◽  
Shoji Yamamoto ◽  
Chuki Hongo ◽  
Hajime Kayanne ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Belowground Biomass ◽  
Blue Carbon ◽  
Back Reef ◽  
Major Mechanism ◽  
Seagrass Meadows ◽  
Sedimentary Organic Carbon ◽  
Seagrass Biomass ◽  
Dead Plant

Abstract. Carbon captured by marine living organisms is called “blue carbon”, and seagrass meadows are a dominant blue carbon sink. However, our knowledge of how seagrass increases sedimentary organic carbon (OC) stocks is limited. We investigated two pathways of OC accumulation: trapping of organic matter in the water column and the direct supply of belowground seagrass detritus. We developed a new type of box corer to facilitate the retrieval of intact cores that preserve the structures of both sediments (including coarse sediments and dead plant structures) and live seagrasses. We measured seagrass density, total OC mass (OCtotal) (live seagrass OC biomass (OCbio) + sedimentary OC mass (OCsed)), and the stable carbon isotope ratio (δ13C) of OCsed and its potential OC sources at Thalassia hemprichii dominated back-reef and Enhalus acoroides dominated estuarine sites in the tropical Indo-Pacific region. At points with vegetation, OCbio accounted for 25 % and OCsed for 75 % of OCtotal; this contribution of OCbio to OCtotal is higher than in globally compiled data. Belowground detritus accounted for ∼ 90 % of the OC mass of dead plant structures (> 2 mm in size) (OCdead). At the back-reef site, belowground seagrass biomass, OCdead, and δ13C of OCsed (δ13Csed) were positively correlated with OCsed, indicating that the direct supply of belowground seagrass detritus is a major mechanism of OCsed accumulation. At the estuarine site, aboveground seagrass biomass was positively correlated with OCsed but δ13Csed did not correlate with OCsed, indicating that trapping of suspended OC by seagrass leaves is a major mechanism of OCsed accumulation there. We inferred that the relative importance of these two pathways may depend on the supply (productivity) of belowground biomass. Our results indicate that belowground biomass productivity of seagrass meadows, in addition to their aboveground morphological complexity, is an important factor controlling their OC stock. Consideration of this factor will improve global blue carbon estimates.

scholarly journals Organic carbon inventories in natural and restored Ecuadorian mangrove forests

2013 ◽  
Author(s):  
Amanda G DelVecchia ◽  
John F Bruno ◽  
Larry K Benninger ◽  
Marc Alperin ◽  
Ovik Banerjee ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Carbon Storage ◽  
Organic Matter Content ◽  
Carbon Stocks ◽  
Organic Carbon Content ◽  
Mangrove Forests ◽  
Storage Potential ◽  
Sediment Carbon

Because mangroves can capture and store organic carbon, their protection and restoration is an obvious component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested) surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g). Results suggest that average soil carbon storage is 0.055 ± 0.002 g∙cm-3 (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE) up to 1 m deep in natural sites, and 0.058 ± 0.002 g∙cm-3 (8.0 ± 0.3%) in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks.

scholarly journals Mechanisms of soil carbon storage in experimental grasslands

2007 ◽  
Vol 4 (5) ◽  
pp. 3829-3862
Author(s):  
S. Steinbeiss ◽  
V. M. Temperton ◽  
G. Gleixner
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Solution ◽  
Carbon Storage ◽  
Amaranthus Retroflexus ◽  
Plant Litter ◽  
C3 Plants ◽  
Litter Input

Abstract. We investigated the fate of root and litter derived carbon into soil organic matter and dissolved organic matter in soil profiles, in order to explain unexpected positive effects of plant diversity on carbon storage. A time series of soil and soil solution samples was investigated at the field site of The Jena Experiment. In addition to the main biodiversity experiment with C3 plants, a C4 species (Amaranthus retroflexus L.) naturally labeled with 13C was grown on an extra plot. Changes in organic carbon concentration in soil and soil solution were combined with stable isotope measurements to follow the fate of plant carbon into the soil and soil solution. A split plot design with plant litter removal versus double litter input simulated differences in biomass input. After 2 years, the no litter and double litter treatment, respectively, showed an increase of 381 g C m−2 and 263 g C m−2 to 20 cm depth, while 71 g C m−2 and 393 g C m−2 were lost between 20 and 30 cm depth. The isotopic label in the top 5 cm indicated that 11 and 15% of soil organic carbon were derived from plant material on the no litter and the double litter treatment, respectively. Without litter, this equals the total amount of carbon newly stored in soil, whereas with double litter this corresponds to twice the amount of stored carbon. Our results indicate that litter input resulted in lower carbon storage and larger carbon losses and consequently accelerated turnover of soil organic carbon. Isotopic evidence showed that inherited soil organic carbon was replaced by fresh plant carbon near the soil surface. Our results suggest that primarily carbon released from soil organic matter, not newly introduced plant organic matter, was transported in the soil solution and contributed to the observed carbon storage in deeper horizons.

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