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Cross-continental shelf trends in coral δ15N on the Great Barrier reef : further consideration of the reef nutrient paradox
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sammarco, Paul W. Risk, Michael J. Schwarcz, Henry P. Heikoop, Jeffrey M. |
| Copyright Year | 1999 |
| Abstract | In this study, we investigate potential sources of nitrogen for the scleractinian coral Porites lobata in a transect across the central region of the Great Barrier Reef, Australia. The experiment followed a 1-way, Model I, nested ANOVA design. We sampled colonies of P. lobata from 12 reefs spanning the 110 km wide continental shelf at 5 m depth, and determined the δ 15 N signature in tissue extracts (with zooxanthellae; n = 46). The response curve of the δ 15 N was found to be curvilinear, yielding a highly significant parabolic relationship with distance from shore (p < 0.001, second-order least-squares polynomial regression). Highest values of δ 15 N were observed inshore (5.0 to 5,5‰), lowest values at the mid-shelf (∼3.8‰), and high values again offshore (5.2‰), We suggest the following causal factors, based on environmental characteristics and phenomena known to occur in this region: (1) inshore corals may be receiving much of their nitrogen from terrigenous sources; (2) mid-shelf corals may be receiving at least some of their nitrogen from associated algal mats known to possess high rates of nitrogen-fixation in this region, which in turn could lower δ 15 N values; and (3) offshore corals may be receiving their nitrogen from seasonal, nutrient-rich, cold-water intrusions or upwellings, documented to occur in this area. |
| Starting Page | 131 |
| Ending Page | 138 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.3354/meps180131 |
| Volume Number | 180 |
| Alternate Webpage(s) | https://www.int-res.com/articles/meps/180/m180p131.pdf |
| Alternate Webpage(s) | https://doi.org/10.3354/meps180131 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
