Quantifying functional consequences of habitat degradation on a Caribbean coral reef
<p>Coral reefs are declining worldwide. The abundance of corals has decreased alongside a rise of filter feeders, turf, and algae in response to intensifying human pressures. This shift in prevalence of functional groups alters the biogeochemical processes in tropical water ecosystems, thereby...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-12-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/18/6501/2021/bg-18-6501-2021.pdf |
| _version_ | 1819239034746044416 |
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| author | A. E. Webb D. M. de Bakker D. M. de Bakker K. Soetaert T. da Costa S. M. A. C. van Heuven F. C. van Duyl G.-J. Reichart G.-J. Reichart L. J. de Nooijer |
| author_facet | A. E. Webb D. M. de Bakker D. M. de Bakker K. Soetaert T. da Costa S. M. A. C. van Heuven F. C. van Duyl G.-J. Reichart G.-J. Reichart L. J. de Nooijer |
| author_sort | A. E. Webb |
| collection | DOAJ |
| description | <p>Coral reefs are declining worldwide. The abundance of corals has decreased alongside a rise of filter feeders, turf, and algae in response to intensifying human pressures. This shift in prevalence of functional groups alters the biogeochemical processes in tropical water ecosystems, thereby influencing reef functioning. An urgent challenge is to understand the functional consequences of these shifts to develop suitable management strategies that aim at preserving the biological functions of reefs.</p>
<p>Here, we quantify biogeochemical processes supporting key reef functions (i.e. net community calcification (NCC) and production (NCP) and nutrient recycling) in situ for five different benthic assemblages currently dominating shallow degraded Caribbean reef habitats. To this end, a transparent custom-made enclosure was placed over communities dominated by either one of five functional groups – coral, turf and macroalgae, bioeroding sponges, cyanobacterial mats, or sand – to determine chemical fluxes between these communities and the overlying water, during both day and night. To account for the simultaneous influence that distinct biogeochemical processes have on measured variables, the rates were then derived by solving a model consisting of differential equations describing the contribution of each process to the measured chemical fluxes.</p>
<p>Inferred rates were low compared to those known for reef flats worldwide. Reduced accretion potential was recorded, with negative or very modest net community calcification rates for all communities. Net production during the day was also low, suggesting limited accumulation of biomass through photosynthesis and remineralisation of organic matter at night was relatively high in comparison, resulting in net heterotrophy over the survey period for most communities. Estimated recycling processes (i.e. nitrification and denitrification) were high but did not fully counterbalance nutrient release from aerobic mineralisation, rendering all substrates sources of nitrogen. Results suggest similar directions and magnitudes of key biogeochemical processes of distinct communities on this shallow Curaçaoan reef. We infer that the amount and type of organic matter released by abundant algal turfs and cyanobacterial mats on this reef likely enhances heterotroph activity and stimulates the proliferation of less diverse copiotrophic microbial populations, rendering the studied reef net heterotrophic and drawing the biogeochemical “behaviour” of distinct communities closer to each other.</p> |
| first_indexed | 2024-12-23T13:45:42Z |
| format | Article |
| id | doaj.art-6c329da79408449787e25d5edb5386ea |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-23T13:45:42Z |
| publishDate | 2021-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-6c329da79408449787e25d5edb5386ea2022-12-21T17:44:44ZengCopernicus PublicationsBiogeosciences1726-41701726-41892021-12-01186501651610.5194/bg-18-6501-2021Quantifying functional consequences of habitat degradation on a Caribbean coral reefA. E. Webb0D. M. de Bakker1D. M. de Bakker2K. Soetaert3T. da Costa4S. M. A. C. van Heuven5F. C. van Duyl6G.-J. Reichart7G.-J. Reichart8L. J. de Nooijer9Department of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the NetherlandsDepartment of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the NetherlandsWageningen Marine Research, Wageningen University and Research, Den Helder, the NetherlandsDepartment of Estuarine and Delta Systems, NIOZ Royal Netherlands Institute for Sea Research, Yerseke, the NetherlandsDepartment of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the NetherlandsCIO Centre for Isotope Research, Groningen University, Groningen, the NetherlandsDepartment of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the NetherlandsDepartment of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the NetherlandsDepartment of Earth Sciences, Utrecht University, Utrecht, the NetherlandsDepartment of Ocean Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Hoorn, the Netherlands<p>Coral reefs are declining worldwide. The abundance of corals has decreased alongside a rise of filter feeders, turf, and algae in response to intensifying human pressures. This shift in prevalence of functional groups alters the biogeochemical processes in tropical water ecosystems, thereby influencing reef functioning. An urgent challenge is to understand the functional consequences of these shifts to develop suitable management strategies that aim at preserving the biological functions of reefs.</p> <p>Here, we quantify biogeochemical processes supporting key reef functions (i.e. net community calcification (NCC) and production (NCP) and nutrient recycling) in situ for five different benthic assemblages currently dominating shallow degraded Caribbean reef habitats. To this end, a transparent custom-made enclosure was placed over communities dominated by either one of five functional groups – coral, turf and macroalgae, bioeroding sponges, cyanobacterial mats, or sand – to determine chemical fluxes between these communities and the overlying water, during both day and night. To account for the simultaneous influence that distinct biogeochemical processes have on measured variables, the rates were then derived by solving a model consisting of differential equations describing the contribution of each process to the measured chemical fluxes.</p> <p>Inferred rates were low compared to those known for reef flats worldwide. Reduced accretion potential was recorded, with negative or very modest net community calcification rates for all communities. Net production during the day was also low, suggesting limited accumulation of biomass through photosynthesis and remineralisation of organic matter at night was relatively high in comparison, resulting in net heterotrophy over the survey period for most communities. Estimated recycling processes (i.e. nitrification and denitrification) were high but did not fully counterbalance nutrient release from aerobic mineralisation, rendering all substrates sources of nitrogen. Results suggest similar directions and magnitudes of key biogeochemical processes of distinct communities on this shallow Curaçaoan reef. We infer that the amount and type of organic matter released by abundant algal turfs and cyanobacterial mats on this reef likely enhances heterotroph activity and stimulates the proliferation of less diverse copiotrophic microbial populations, rendering the studied reef net heterotrophic and drawing the biogeochemical “behaviour” of distinct communities closer to each other.</p>https://bg.copernicus.org/articles/18/6501/2021/bg-18-6501-2021.pdf |
| spellingShingle | A. E. Webb D. M. de Bakker D. M. de Bakker K. Soetaert T. da Costa S. M. A. C. van Heuven F. C. van Duyl G.-J. Reichart G.-J. Reichart L. J. de Nooijer Quantifying functional consequences of habitat degradation on a Caribbean coral reef Biogeosciences |
| title | Quantifying functional consequences of habitat degradation on a Caribbean coral reef |
| title_full | Quantifying functional consequences of habitat degradation on a Caribbean coral reef |
| title_fullStr | Quantifying functional consequences of habitat degradation on a Caribbean coral reef |
| title_full_unstemmed | Quantifying functional consequences of habitat degradation on a Caribbean coral reef |
| title_short | Quantifying functional consequences of habitat degradation on a Caribbean coral reef |
| title_sort | quantifying functional consequences of habitat degradation on a caribbean coral reef |
| url | https://bg.copernicus.org/articles/18/6501/2021/bg-18-6501-2021.pdf |
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