SS018AQUATICECOSYSTEMDEVELOPMENT: DOES FUNCTION FOLLOW FORM?

Aquatic ecosystems constitute a network of interactions transferring matter and energy between organisms. Environmental conditions determine distribution and performance of organisms, thereby network's structure and capabilities to deliver a particular function. Organic matter and nutrients supply and maintain trophic interactions in organism assemblages, thus any changes in biogeochemical cycles (e.g., carbon, nutrients) driven by environmental disturbances may cause alterations in network structure, energy flow patterns and consequently the delivery of ecosystem services. Despite the growing research on "environmental change," there is still gap in knowledge related to the dynamics of ecosystem services under changing aquatic systems. This session will primarily focus on potential changes in services delivered by aquatic ecosystem beyond gross biogeochemical cycles. The aim of this session is to shed light on a number of open questions: Are there general patterns of such changes or a set of distinct scenarios? Is there any suitable conceptual framework available for such studies or do we need to develop one? Could such studies gain value from the inclusion of the human factor i.e. social dynamics? Will there be any functional changes in storage and fluxes of carbon due to complexity in ecosystem services under a changing environment? We invite both case studies and theoretical analysis on how multiple environmental drivers can induce multiple responses at different organizational levels and how such effects translate into changes of a significant ecosystem service. Keywords: Biogeochemistry, Carbon, Ecosystem Service, Food Web, Functional Ecolog

Carbon sequestration by mangrove forest: One approach for managing carbon dioxide emission from coal-based power plant

WOS:000416495400016International audienceMangroves are known as natural carbon sinks, taking CO2 out of the atmosphere and store it in their biomass for many years. This study aimed to investigate the capacity of world's largest mangrove, the Sundarbans (Indian part) to sequester anthropogenic CO2 emitted from the proximate coal-based thermal power plant in Kolaghat (∼100 km away from mangrove site). Study also includes Kolkata, one of the largest metropolises of India (∼150 km away from mangrove site) for comparing micrometeorological parameters, biosphere-atmosphere CO2 exchange fluxes and atmospheric pollutants between three distinct environments: mangrove-power plant-metropolis. Hourly sampling of atmospheric CO2 in all three sites (late December 2011 and early January 2012) revealed that CO2 concentrations and emission fluxes were maximum around the power plant (360–621 ppmv, 5.6–56.7 mg m−2s−1 respectively) followed by the metropolis (383–459 ppmv, 3.8–20.4 mg m−2s−1 respectively) and mangroves (277–408 ppmv, −8.9–11.4 mg m−2s−1, respectively). Monthly coal consumption rates (41–57, in 104 ton month−1) were converted to CO2 suggesting that 2.83 Tg C was added to the atmosphere in 2011 for the generation of 7469732 MW energy from the power plant. Indian Sundarbans (4264 km2) sequestered total of 2.79 Tg C which was 0.64% of the annual fossil fuel emission from India in the same time period. Based on these data from 2010 to 2011, it is calculated that about 4328 km2 mangrove forest coverage is needed to sequester all CO2 emitted from the Kolaghat power plant

Carbon stocks and fluxes in Asia-Pacific mangroves: current knowledge and gaps

Mangrove forest plays a key role in regulating climate change, earth carbon cycling and other biogeochemical processes within blue carbon ecosystems. Therefore, mangrove forests should be incorporated into Earth system climate models with the aim of understanding future climate change. Despite multiple carbon stock and flux assessments taking place over the past couple of decades, concrete knowledge of carbon source/sink patterns is largely lacking, particularly in the biodiversity-rich Asia-Pacific (AP) region with its 68 493 km ^2 of mangrove area. Thus, to understand the gaps in mangrove blue carbon research in the AP region, we summarize a recent decade-long inventory of carbon stock pools (aboveground, belowground and soil) and biogeochemical flux components (burial, export/import, soil-air and water-air CO _2 flux) across 25 AP countries to understand the current knowledge and gaps. While carbon stock assessments of individual components are available for all 25 countries, whole ecosystem carbon stocks—including live and standing dead aboveground and belowground, downed woody debris and soil carbon stocks—are often lacking, even in highly researched countries like Indonesia. There is restricted knowledge around biogeochemical carbon fluxes in 55% of the countries, suggesting poor carbon flux research across the region. Focusing on flux components, reports on sediment-to-sea carbon exports are extremely limited (coming from just nine countries in the AP region). There is notable scarcity of data on carbon export fluxes in Indonesian mangroves. Given the key role AP mangroves play in climate change mitigation worldwide, more detailed and methodologically comparable investigation of biogeochemical source/sink processes is required to better understand the role of this large carbon source in global carbon stocks and fluxes, and hence, global climate

Correction: Sharma et al. Successive Cyclones Attacked the World’s Largest Mangrove Forest Located in the Bay of Bengal under Pandemic. Sustainability 2022, 14, 5130

The authors would like to make the following corrections about the published paper [...

State of rare earth elements in the sediment and their bioaccumulation by mangroves: a case study in pristine islands of Indian Sundarban

WOS:000464851100069International audienceThe mangrove ecosystems are known to efficiently sequester trace metals both in sediments and plant biomass. However, less is known about the chemistry of rare earth elements (REE) in the coastal environments, especially in the world's largest mangrove province, the Sundarban. Here, the concentration of REE in the sediment and plant organs of eight dominant mangrove species (mainly Avicennia sp.) in the Indian Sundarban was measured to assess REE sources, distribution, and bioaccumulation state. Results revealed that light REE (LREE) were more concentrated than the heavy REE (HREE) (128-144 mg kg(-1) and 12-15 mg kg(-1), respectively) in the mangrove sediments, with a relatively weak positive europium anomaly (Eu/Eu* = 1.03-1.14) with respect to North American shale composite. The primary source of REE was most likely linked to aluminosilicate weathering of crustal materials, and the resultant increase in LREE in the detritus. Vertical distribution of REE in one of the long cores from Lothian Island was altered by mangrove root activity and dependent on various physicochemical properties in the sediment (e.g., Eh, pH, organic carbon, and phosphate). REE uptake by plants was higher in the below-ground parts than in the above-ground plant tissues (root = 3.3 mg kg(-1), leaf + wood = 1.7 mg kg(-1)); however, their total concentration was much lower than in the sediment (149.5 mg kg(-1)). Species-specific variability in bioaccumulation factor and translocation factor was observed indicating different REE partitioning and varying degree of mangrove uptake efficiency. Total REE stock in plant (above + live below ground) was estimated to be 168 g ha(-1) with LREE contributing similar to 90% of the stock. This study highlighted the efficiency of using REE as a biological proxy in determining the degree of bioaccumulation within the mangrove environment

Mangrove-Derived Organic and Inorganic Carbon Exchanges Between the Sinnamary Estuarine System (French Guiana, South America) and Atlantic Ocean

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JG005739International audienceThere is growing evidence that a substantial fraction of the dissolved organic and inorganic carbon (DOC and DIC) and particulate organic carbon (POC) can be exported from mangroves to the ocean. Yet our understanding of C fluxes in mangrove forests is limited to only few regional studies that exclude the world's longest sediment dispersal system connected to the Amazon River. The present study aims at (1) examining tidal fluctuations of DOC, POC, and DIC; their isotopes; and optical properties such as chromophoric dissolved organic matter (CDOM) and (2) estimating their exchange fluxes between the mangroves and adjacent coastal water in the Sinnamary estuary, French Guiana. Time series observation highlighted that physical processes coupled to tides controlled diel dynamics and sources of DOC (e.g., litter leaching and pore water seepage) and POC (microphytobenthos, sediment resuspension, and bioturbation activities). Intense benthic remineralization could account for high water column pCO2 and DIC exchange flux during the low tide. Mangrove-derived DOC export to inner shelf (8.14 g C m−2 day−1) was exceeding import of POC and DIC from the mud bank and marine sources to the mangroves (1.35 and 0.90 g C m−2 day−1, respectively). Because of specific dynamics of the Amazon mobile muds, local geomorphology, water column stratification, and environmental forcing, Guianese mangroves cannot be seen as simple C exporters to the Atlantic waters. These first data setting on C fluxes for the region should be included along with other studies to improve global mangrove C budget estimate

Accumulation, transport and toxicity of arsenic in the Sundarbans mangrove, India

International audienceArsenic (As), a toxic element is a concern for the habitants in and around the coastal areas of West Bengal (India) where world's largest Sundarbans mangrove is situated. Little is known about the potential of these mangroves in storing As within their biomass and transporting to the Bay of Bengal. A comprehensive yearly data of above ground and below ground biomass (AGB, BGB), and exchange fluxes like litter fall, plant uptake, sedimentary diffusion/advection, and suspended particle deposition were used in a box model for constructing As budget for the Sundarbans mangroves. About 80% of total As was stored in AGB while As stock in sediment was several hundred times higher than in the AGB and BGB indicating poor bioaccumulation and sequestration capacity of the mangroves, which was further supported by higher As loss though litterfall (16.8 mu g As m(-2) month(-1)) compared to gain through plant uptake (0.05 mu g As m(-2) month(-)(1)). About 65% of the river-discharged As exported to the Bay of Bengal, the rest amounting to 67.2 x 10(3) kg yr(-1) remained in the mangrove estuaries. Although ecotoxicological indexes confirmed low As pollution impact in the Sundarbans, mass budget revealed net As addition in the estuarine ecosystem (67.2 Mg As yr(-1)), mainly derived from natural and anthropogenic sources such as, contamination via atmospheric dust deposition. Overall reservoir-based mass budget showed weak As sequestration capacity by these mangroves. The approach developed for As in this study could be applied to other major metals to estimate metal sequestration and conservation potential by the Sundarbans mangroves