Although the exact fate of much of the oil and dispersants for the Deepwater Horizon oil spill (DHOS) are still under examination, large quantities of oil are believed to have sunk to the bottom. (An observation apparently confirmed by Dr. Smantha Joye and others recently on the R/V Ocean Veritas.) As such, benthic communities were likely largely impacted including organisms that live in the sediments such as meiofaunal or microbial communities.
The Benthic Meiofauna Survey proposed here will examine interstitial animals and selected microbes from areas believed to be impacted by DHOS. Additionally, areas not suspected to have been impacted by the oil or dispersants will be examined for comparative purposes. This work builds on a survey conducted for the past 3 years (i.e., pre-spill data), providing meiofaunal data in the Northern Gulf of Mexico (NGoM) from 2007, 2008, & 2009, including near shore and offshore stations (see Baguley, 2004; Rowe & Kennicutt, 2008).
Major questions examined include:
- Q1: Has DHOS impacted meiofaunal and microbial populations in the NGoM?
(Do the same locations show changes through time? Can we assess impact by comparison to non-impacted sites?)
- Q2: For areas where impact can be documented, are organismal communities recovering?
- Q3: Are there sentinel groups of meiofaunal or microbes whose populations are most affected?
- Q4: Will data from different time points after DHOS show significant difference?
(Can recovery be detected?)
The null hypotheses for these questions assume that no changes have or will occur. If an impact is detected, the null hypothesis will be that the recovery data from 2011 will show no change from the impact data of 2010.
- H1: No impact will be detectable when comparing pre-spill data and post-spill 2010 meiofaunal populations in the Gulf.
- H2: Meiofaunal and microbial populations will not be significantly different when comparing suspected impact areas to non-impact areas.
- H3: If an impact is detected when comparing pre-spill and post-spill data, and when comparing impact vs. non-impact areas, no change will be detected to indicate recovery when sampling occurs one year later (2011).