Inorganic nutrient availability affects organic matter fluxes and metabolic activity in the soft coral genus Xenia
V.N. Bednarz
Malik S. Naumann
W. Niggl
C. Wild
Abstract
The release of organic matter (OM) by scleractinian corals represents a key physiological process that importantly contributes to coral reef ecosystem functioning, and is affected by inorganic nutrient availability. Although OM fluxes have been studied for several dominant reef taxa, no information is available for soft corals, one of the major benthic groups in tropical reef environments. Thus, this study investigates OM fluxes along with other key physiological parameters (i.e. photosynthesis, respiration and chlorophyll a tissue content) in the common soft coral genus Xenia after a 4-week exposure period to elevated ammonium (N; 20.0 μmol l−1), phosphate (P; 2.0 μmol l−1) and combined inorganic nutrient enrichment treatment (N+P). Corals maintained without nutrient enrichment served as non-treated controls and revealed constant uptake rates for particulate organic carbon (POC) (−0.315±0.161 mg POC m−2 coral surface area h−1), particulate nitrogen (PN) (−0.053±0.018 mg PN m−2 h−1) and dissolved organic carbon (DOC) (−4.8±2.1 mg DOC m−2 h−1). Although DOC uptake significantly increased in the N treatment, POC flux was not affected. The P treatment significantly enhanced PN release as well as photosynthesis and respiration rates, suggesting that autotrophic carbon acquisition of zooxanthellae endosymbionts influences OM fluxes by the coral host. Our physiological findings confirm the significant effect of inorganic nutrient availability on OM fluxes and key metabolic processes for the soft coral Xenia, and provide the first clues on OM cycles initiated by soft corals in reef environments exposed to ambient and elevated inorganic nutrient concentrations.
Bednarz V.N., Naumann M.S., Niggl W. and Wild C. (2012) Inorganic nutrient availability affects organic matter fluxes and metabolic activity in the soft coral genus Xenia. Journal of Experimental Biology 215(20): 3672-3679. 10.1242/jeb.072884
@article{Bednarz2012,
Title = {Inorganic nutrient availability affects organic matter fluxes and metabolic activity in the soft coral genus Xenia},
Author = {Bednarz, V.N. and Naumann, Malik S. and Niggl, W. and Wild, C.},
Editor = {},
Journal = {Journal of Experimental Biology},
Year = {2012},
Pages = {3672-3679},
Volume = {215},
Doi = {10.1242/jeb.072884},
Abstract = {The release of organic matter (OM) by scleractinian corals represents a key physiological process that importantly contributes to coral reef ecosystem functioning, and is affected by inorganic nutrient availability. Although OM fluxes have been studied for several dominant reef taxa, no information is available for soft corals, one of the major benthic groups in tropical reef environments. Thus, this study investigates OM fluxes along with other key physiological parameters (i.e. photosynthesis, respiration and chlorophyll a tissue content) in the common soft coral genus Xenia after a 4-week exposure period to elevated ammonium (N; 20.0 μmol l−1), phosphate (P; 2.0 μmol l−1) and combined inorganic nutrient enrichment treatment (N+P). Corals maintained without nutrient enrichment served as non-treated controls and revealed constant uptake rates for particulate organic carbon (POC) (−0.315±0.161 mg POC m−2 coral surface area h−1), particulate nitrogen (PN) (−0.053±0.018 mg PN m−2 h−1) and dissolved organic carbon (DOC) (−4.8±2.1 mg DOC m−2 h−1). Although DOC uptake significantly increased in the N treatment, POC flux was not affected. The P treatment significantly enhanced PN release as well as photosynthesis and respiration rates, suggesting that autotrophic carbon acquisition of zooxanthellae endosymbionts influences OM fluxes by the coral host. Our physiological findings confirm the significant effect of inorganic nutrient availability on OM fluxes and key metabolic processes for the soft coral Xenia, and provide the first clues on OM cycles initiated by soft corals in reef environments exposed to ambient and elevated inorganic nutrient concentrations.},
}
TY - JOUR
AU - Bednarz, V.N.
AU - Naumann, Malik S.
AU - Niggl, W.
AU - Wild, C.
TI - Inorganic nutrient availability affects organic matter fluxes and metabolic activity in the soft coral genus Xenia
T2 - Journal of Experimental Biology
PY - 2012
SP - 3672-3679
VL - 215
DO - 10.1242/jeb.072884
AB - The release of organic matter (OM) by scleractinian corals represents a key physiological process that importantly contributes to coral reef ecosystem functioning, and is affected by inorganic nutrient availability. Although OM fluxes have been studied for several dominant reef taxa, no information is available for soft corals, one of the major benthic groups in tropical reef environments. Thus, this study investigates OM fluxes along with other key physiological parameters (i.e. photosynthesis, respiration and chlorophyll a tissue content) in the common soft coral genus Xenia after a 4-week exposure period to elevated ammonium (N; 20.0 μmol l−1), phosphate (P; 2.0 μmol l−1) and combined inorganic nutrient enrichment treatment (N+P). Corals maintained without nutrient enrichment served as non-treated controls and revealed constant uptake rates for particulate organic carbon (POC) (−0.315±0.161 mg POC m−2 coral surface area h−1), particulate nitrogen (PN) (−0.053±0.018 mg PN m−2 h−1) and dissolved organic carbon (DOC) (−4.8±2.1 mg DOC m−2 h−1). Although DOC uptake significantly increased in the N treatment, POC flux was not affected. The P treatment significantly enhanced PN release as well as photosynthesis and respiration rates, suggesting that autotrophic carbon acquisition of zooxanthellae endosymbionts influences OM fluxes by the coral host. Our physiological findings confirm the significant effect of inorganic nutrient availability on OM fluxes and key metabolic processes for the soft coral Xenia, and provide the first clues on OM cycles initiated by soft corals in reef environments exposed to ambient and elevated inorganic nutrient concentrations.
ER -
