A Re-Assessment of the Diatom Communities in Perdido Bay and Pensacola Bay in Response to the Deepwater Horizon Oil Spill
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Authors
Adhikari, Arjun
Issue Date
2012-09-20
Type
Thesis
Language
en_US
Keywords
diotoms , oil spill , Deepwater Horizon , Pensacola Bay , Gulf of Mexico , Species Diversity
Alternative Title
Abstract
A primarily taxonomical study was conducted to assess the distribution of
diatoms after the Deepwater Horizon oil rig explosion in the Gulf of Mexico, April 20,
2010. The study is focused on the possible effects of the Deepwater Horizon oil spill on
diatoms. Sampling was conducted on bimonthly basis for six months at Perdido Bay and
Pensacola Bay, starting 24 September, 2010, and ending 10 May, 2011. Samples were
collected from the surface as net plankton, sediment, and as whole water. Global
Positioning System (GPS) was used to keep a record of exact locations of sampling.
Physical characteristics such as water temperature, dissolved oxygen (DO), light
intensity, salinity, and turbidity were taken at the time of sampling. Samples were
preserved in Lugol’s iodine to avoid further growth and were transported back to the lab
for further testing. The primary objectives of the study was diatom community
characterization, comparing datasets with previous studies, and recording the number of
deformed diatom valves possibly attributed to the Gulf of Mexico oil spill. A total of 524
species were encountered contributing to 90 genera. Species diversity was measured
using the Shannon-Wiener index. Relative abundance of species was also calculated by
counting at-least 400 valves in one transect per slide for each sample. To characterize the community structure, PRIMER-E ver. 5.0 was used to assess the Bray-Curtis similarity index and to perform multidimensional scaling, and principal component analysis. The results showed a high diversity and variability in the Perdido/Pensacola Bay ecosystem and an insignificant number of the deformed valves (<< 0.01%).
Description
A thesis by Arjun Adhikari