Variations in primary production of northern Gulf of Mexico continental shelf waters linked to nutrient inputs from the Mississippi River

作者：Steven E. Lohrenz, GL Fahnenstiel, DG Redalje, GA Lang, Xinping Chen, MJ Dagg · 发表于：Marine Ecology Progress Series · 年份：1997 · DOI：10.3354/meps155045 · 被引用次数：286 · 研究领域：Marine and coastal ecosystems、Aquatic Ecosystems and Phytoplankton Dynamics、Mercury impact and mitigation studies

Increases in nutrient concentrations in the Mississippi River over the past 35 yr have led to speculation that primary production of organic carbon has been elevated as a result of increased nutrient fluxes that have occurred in the northern Gulf of Mexico coastal ecosystem.However, studies thus far have not provided direct demonstration of temporal relationships between measured primary production in continental shelf waters and nver-borne nutrient fluxes.This ~nvestlgation co~npared temporal variations in primary production with associated annual and interannual changes in riverborne nutrient inputs.Prlmary production In shelf waters near the river delta were found to b e signlflcantly correlated with nitrate (NO1-) + nitrite (NO? ) concentrations and fluxes over a 6 yr period from 1988 to 1994.Although light limitation was probably an important factor during winter months, a positive correlation was demonstrated between river inputs of NO,-+NO; and primary production for data collected from other times of the year.Peak nutrient inputs generally occurred in the spring.The magnitude of the riverborne NO? +NO, inputs averaged 106% of estimated nitrogen requirements for phytoplankton in the river-impacted region, considerably greater than in Amazon shelf waters, which have been less subject to anthropogenic nutrient increases.The possibility exists that further Increases In anthropogenic nutrients in the ~i s s i s s ~p p i River could lead to h ~g h e r and more widespread pr...