Monday, May 2, 2011

New paper asks if oil spill made the Gulf of Mexico greener

A paper published today in Geophysical Research Letters finds the initial satellite measurements following the BP Gulf of Mexico oil spill show a significant increase in phytoplankton biomass. Begs the question, did plankton consume spilled oil to help account for much less dire consequences from the spill than predicted?

Did the northeastern Gulf of Mexico become greener after the Deepwater Horizon oil spill?

Authors: Chuanmin Hu, Robert H. Weisberg, Yonggang Liu, Lianyuan Zheng, Kendra L. Daly, David C. English, Jun Zhao and Gabriel A. Vargo

Abstract: Assessment of direct and indirect impacts of oil and dispersants on the marine ecosystem in the northeastern Gulf of Mexico (NEGOM) from the Deepwater Horizon oil spill (April – July 2010) requires sustained observations over multiple years. Here, using satellite measurements, numerical circulation models, and other environmental data, we present some initial results on observed biological changes at the base of the food web. MODIS fluorescence line height (FLH, a proxy for phytoplankton biomass) shows two interesting anomalies. The first is statistically significant (>1 mg m−3 of chlorophyll-a anomaly), in an area exceeding 11,000 km2 in the NEGOM during August 2010, about 3 weeks after the oil well was capped. FLH values in this area are higher (i.e., water is greener) than in any August since 2002, and higher than ever since 2002 in an area of ∼3,000 km2. Analyses of ocean circulation and other environmental data suggest that this anomaly may be attributed to the oil spill. The second is a spatially coherent FLH anomaly during December 2010 and January 2011, extending from Mobile Bay to the Florida Keys (mainly between 30 and 100-m isobaths). This anomaly appears to have resulted from unusually strong upwelling and mixing events during late fall. Available data are insufficient to support or reject a hypothesis that the subsurface oil may have contributed to the enhanced biomass during December 2010 and January 2011.

1 comment:

  1. Glad you picked up on this. Oil is a fertilizer. Spray crude oil on a field and it will turn green... Assuming you don't overdo it.

    I have no doubt the crude oil released has ultimately acted as a fertilizer to phytoplankton. In the initial release, the high concentrations were obviously deadly to marine life, but after it's dispersed, I knew it would have the opposite effect...

    I am suspicious of the effects of "Corexit" however to improve the situation. Call me crazy, but I simply do not trust corporations to tell the truth when it would negatively impact their bottom line.

    Frankly, I think fertilizer run-off which caused the dead zone is many orders of magnitude worse than the spill, as it has been ongoing for many years. It would be ironic in the extreme if the Gulf spill helped to mitigate the tremendous anoxic dead zone in the Gulf.