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Coral reefs chronically exposed to river sediment plumes in the southwestern Caribbean: Rosario Islands, Colombia.
Sci Total Environ. 2016 May 15; 553:316-329.ST

Abstract

Politicians do not acknowledge the devastating impacts riverine sediments can have on healthy coral reef ecosystems during environmental debates in Caribbean countries. Therefore, regional and/or local decision makers do not implement the necessary measures to reduce fluvial sediment fluxes on coral reefs. The Magdalena River, the main contributor of continental fluxes into the Caribbean Sea, delivers water and sediment fluxes into the Rosario Islands National Park, an important marine protected area in the southwestern Caribbean. Until now, there is no scientific consensus on the presence of sediment fluxes from the Magdalena River in the coral reefs of the Rosario Islands. Our hypothesis is that high sediment and freshwater inputs from the Magdalena have been present at higher acute levels during the last decade than previously thought, and that these runoff pulses are not flashy. We use in-situ calibrated MODIS satellite images to capture the spatiotemporal variability of the distribution of suspended sediment over the coral reefs. Furthermore, geochemical data are analyzed to detect associated sedimentation rates and pollutant dispersion into the coastal zone. Results confirm that turbidity levels have been much higher than previous values presented by national environmental authorities on coral reefs off Colombia over the last decade. During the 2003-2013-period most of the Total Suspended Sediments (TSS) values witnessed in the sampled regions were above 10mg/l, a threshold value of turbidity for healthy coral reef waters. TSS concentrations throughout the analyzed time were up to 62.3mg/l. Plume pulses were more pronounced during wet seasons of La Niña events in 2002-2003, 2007-2008, and 2009-2010. Reconstructed time series of MODIS TSS indicates that coral reef waters were exposed to river plumes between 19.6 and 47.8% of the entire period of analysis (2000-2013). Further analyses of time series of water discharge and sediment load into the coastal zone during the last two decades show temporal increases in water discharge and sediment load of 28% and 48%, respectively. (210)Pb dating results from two cores indicate sedimentation rates of ~0.75 cm/y of continentally exported clastic muddy sediments that are being deposited on the carbonatic shelf. The cores contain sediments with heavy metals and their concentrations are frequently above the ecologically accepted standards. Overall, the last decade has witnessed stronger magnitudes in fluvial fluxes to the coastal region, which probably coincide with associated declines in healthy coral cover and water quality. Our results emphasize the importance of local stressors, such as runoff and dispersion of turbid plumes, as opposed to ocean warming, disease and hurricanes, which have played a larger role on other coral reefs in the Caribbean. Coral reef management across the southwestern Caribbean, a coastal region influenced by continental fluxes of numerous rivers flowing from the Andes, may only be effective when land and marine-based stressors are simultaneously mitigated.

Authors+Show Affiliations

School of Sciences, Department of Earth Sciences, EAFIT University, Colombia; Teresa Lozano Long Institute of Latin American Studies, University of Texas at Austin, USA. Electronic address: jdrestre@eafit.edu.co.Department of Geography and the Environment, University of Texas at Austin, USA.Department of Geography and the Environment, University of Texas at Austin, USA.Teresa Lozano Long Institute of Latin American Studies, University of Texas at Austin, USA; Department of Geography and the Environment, University of Texas at Austin, USA.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26933966

Citation

Restrepo, Juan D., et al. "Coral Reefs Chronically Exposed to River Sediment Plumes in the Southwestern Caribbean: Rosario Islands, Colombia." The Science of the Total Environment, vol. 553, 2016, pp. 316-329.
Restrepo JD, Park E, Aquino S, et al. Coral reefs chronically exposed to river sediment plumes in the southwestern Caribbean: Rosario Islands, Colombia. Sci Total Environ. 2016;553:316-329.
Restrepo, J. D., Park, E., Aquino, S., & Latrubesse, E. M. (2016). Coral reefs chronically exposed to river sediment plumes in the southwestern Caribbean: Rosario Islands, Colombia. The Science of the Total Environment, 553, 316-329. https://doi.org/10.1016/j.scitotenv.2016.02.140
Restrepo JD, et al. Coral Reefs Chronically Exposed to River Sediment Plumes in the Southwestern Caribbean: Rosario Islands, Colombia. Sci Total Environ. 2016 May 15;553:316-329. PubMed PMID: 26933966.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Coral reefs chronically exposed to river sediment plumes in the southwestern Caribbean: Rosario Islands, Colombia. AU - Restrepo,Juan D, AU - Park,Edward, AU - Aquino,Samia, AU - Latrubesse,Edgardo M, Y1 - 2016/02/28/ PY - 2015/12/03/received PY - 2016/02/19/revised PY - 2016/02/19/accepted PY - 2016/3/3/entrez PY - 2016/3/5/pubmed PY - 2016/12/15/medline KW - Caribbean KW - Coral reef management KW - Magdalena River KW - River plume KW - Rosario Islands KW - Sediment load SP - 316 EP - 329 JF - The Science of the total environment JO - Sci. Total Environ. VL - 553 N2 - Politicians do not acknowledge the devastating impacts riverine sediments can have on healthy coral reef ecosystems during environmental debates in Caribbean countries. Therefore, regional and/or local decision makers do not implement the necessary measures to reduce fluvial sediment fluxes on coral reefs. The Magdalena River, the main contributor of continental fluxes into the Caribbean Sea, delivers water and sediment fluxes into the Rosario Islands National Park, an important marine protected area in the southwestern Caribbean. Until now, there is no scientific consensus on the presence of sediment fluxes from the Magdalena River in the coral reefs of the Rosario Islands. Our hypothesis is that high sediment and freshwater inputs from the Magdalena have been present at higher acute levels during the last decade than previously thought, and that these runoff pulses are not flashy. We use in-situ calibrated MODIS satellite images to capture the spatiotemporal variability of the distribution of suspended sediment over the coral reefs. Furthermore, geochemical data are analyzed to detect associated sedimentation rates and pollutant dispersion into the coastal zone. Results confirm that turbidity levels have been much higher than previous values presented by national environmental authorities on coral reefs off Colombia over the last decade. During the 2003-2013-period most of the Total Suspended Sediments (TSS) values witnessed in the sampled regions were above 10mg/l, a threshold value of turbidity for healthy coral reef waters. TSS concentrations throughout the analyzed time were up to 62.3mg/l. Plume pulses were more pronounced during wet seasons of La Niña events in 2002-2003, 2007-2008, and 2009-2010. Reconstructed time series of MODIS TSS indicates that coral reef waters were exposed to river plumes between 19.6 and 47.8% of the entire period of analysis (2000-2013). Further analyses of time series of water discharge and sediment load into the coastal zone during the last two decades show temporal increases in water discharge and sediment load of 28% and 48%, respectively. (210)Pb dating results from two cores indicate sedimentation rates of ~0.75 cm/y of continentally exported clastic muddy sediments that are being deposited on the carbonatic shelf. The cores contain sediments with heavy metals and their concentrations are frequently above the ecologically accepted standards. Overall, the last decade has witnessed stronger magnitudes in fluvial fluxes to the coastal region, which probably coincide with associated declines in healthy coral cover and water quality. Our results emphasize the importance of local stressors, such as runoff and dispersion of turbid plumes, as opposed to ocean warming, disease and hurricanes, which have played a larger role on other coral reefs in the Caribbean. Coral reef management across the southwestern Caribbean, a coastal region influenced by continental fluxes of numerous rivers flowing from the Andes, may only be effective when land and marine-based stressors are simultaneously mitigated. SN - 1879-1026 UR - https://www.unboundmedicine.com/medline/citation/26933966/Coral_reefs_chronically_exposed_to_river_sediment_plumes_in_the_southwestern_Caribbean:_Rosario_Islands_Colombia_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(16)30351-5 DB - PRIME DP - Unbound Medicine ER -