Sediment-preserved diatom assemblages can distinguish a petroleum activity signal separately from the nutrient signal of the Mississippi River in coastal Louisiana.
We analyzed the preserved diatom assemblages in dated sediment cores collected from five locations in the Louisiana Bight to test if there was a signature of petroleum extraction activities (hopanes and barium) distinct from the well-documented effects of nutrient loading. The results of a multi-dimensional scaling analysis indicate that the diatom assemblage changes documented throughout the 40 year record could be explained by three variables: barium and hopanes concentrations, and Mississippi River nitrogen loading. The results of a canonical correspondence analysis demonstrated that these signals could be distinguished through correlations with specific diatom species. The abundance of Actinoptychus senarius, for example, was negatively correlated with barium and the Pseudo-nitzschia delicatissima complex was positively correlated with nitrogen loading. These results provide a "proof-of-concept" demonstration that diatom assemblages preserved in the sediments can be used to study the effects of petroleum extraction activities, and that these 'petroleum signals' may be distinguished from other significant influences such as nutrient loading.
['Parsons|M L|ML|', 'Turner|R E|RE|', 'Overton|E B|EB|']
D000062:Accidents, Occupational D017377:Diatoms D004784:Environmental Monitoring D004785:Environmental Pollutants D005068:Eutrophication D005843:Geography D019015:Geologic Sediments D060851:Gulf of Mexico D008145:Louisiana D009584:Nitrogen D010578:Petroleum D059392:Petroleum Pollution D011157:Population Dynamics D045483:Rivers D014874:Water Pollutants, Chemical
Eutrophication Gulf of Mexico Hypoxia Oil spill Phytoplankton