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IS THERE A LINGERING IMPACT OF THE MACONDO OIL SPILL ON EPIPHYTE COMMUNITY STRUCTURE AND STABILITY IN THE CHANDELEUR ISLANDS?
Title
IS THERE A LINGERING IMPACT OF THE MACONDO OIL SPILL ON EPIPHYTE COMMUNITY STRUCTURE AND STABILITY IN THE CHANDELEUR ISLANDS?.
Creator
Blonder, Samantha
Abstract / Description
Oil spills can cause deleterious impacts to many coastal organisms, including microalgae. Many microalgae thrive as epiphytes living on macroalgae or seagrass hosts. These epiphytic algae make up part of the microbiome that also includes associated micro- and mesograzers and have a great influence on the surrounding micro-benthic community as well as the overall ecosystem. It is important to understand how these communities are impacted because they can be used as indicators of ecosystem...
Show moreOil spills can cause deleterious impacts to many coastal organisms, including microalgae. Many microalgae thrive as epiphytes living on macroalgae or seagrass hosts. These epiphytic algae make up part of the microbiome that also includes associated micro- and mesograzers and have a great influence on the surrounding micro-benthic community as well as the overall ecosystem. It is important to understand how these communities are impacted because they can be used as indicators of ecosystem health and resilience, as well as potential biomarkers of oil pollution. There is little research, however, on how oil impacts epiphytic communities. The objective of this study was to determine how the community composition of epiphytic microalgae changes due to the influence of natural crude oil exposure. The potential influence of oil exposure was tested by examining 48 epiphyte samples collected from the Chandeleur Islands (Louisiana) in September 2015 and 2016, at sites with exposure to low, moderate, and high levels of oil during the Macondo oil spill. The community composition was identified to the lowest taxonomic units possible, and quantified. The relative abundance, cell size, and biodiversity per composite sample of microalgae were compared against host species distinctions, oil exposure, date and sites through ANOSIM and SIMPER analyses in PRIMER. The data presented suggest that the lingering impact of oil on epiphyte communities persists 5-6 years after the spill. Ecosystem services, however, do not appear to have been altered according to proxy biodiversity comparisons. Diatoms dominated at all sites for all years, similar to baseline compositions. Greater similarity (i.e., stability) was seen between sites with less initial oiling. Overall, these data suggest there are lingering impacts from the oil spill, but the ecological change in community structure is minimal. Due to the lack of existing data on the impacts of oil exposure on these communities, this study provides baseline research for future studies.
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Date Issued
43330.0
Identifier
fgcu_ETD_0255
Format
Document (PDF)
Phytoplankton Responses to Crude Oil and Chemical Dispersant Exposure in Laboratory Culture: Implications for the Deepwater Horizon Oil Spill
Title
Phytoplankton Responses to Crude Oil and Chemical Dispersant Exposure in Laboratory Culture: Implications for the Deepwater Horizon Oil Spill.
Creator
Tyre, Kevin
Abstract / Description
Gulf of Mexico fisheries, accounting for 20% of the total United States Fisheries value, are supported by high phytoplankton productivity. Any disruption to phytoplankton productivity could result in a deleterious trophic cascade effect, crippling these important fisheries. The Deepwater Horizon oil spill may have been such a disruption. The aim of this study was to assess phytoplankton responses to crude oil and chemical dispersant exposure in a laboratory setting. Phytoplankton cultures...
Show moreGulf of Mexico fisheries, accounting for 20% of the total United States Fisheries value, are supported by high phytoplankton productivity. Any disruption to phytoplankton productivity could result in a deleterious trophic cascade effect, crippling these important fisheries. The Deepwater Horizon oil spill may have been such a disruption. The aim of this study was to assess phytoplankton responses to crude oil and chemical dispersant exposure in a laboratory setting. Phytoplankton cultures were exposed to the water accommodated fraction (WAF) of Louisiana Sweet Crude oil (LSC) and the chemical dispersant Corexit EC9500A at high and low concentrations under different salinity and temperature regimes in order to determine phytoplankton responses to these toxicants. Culture health was determined by chlorophyll concentration, cell counts, and photochemical efficiency (PE). Overall, phytoplankton were unaffected by oil WAFs but showed significant reduction in chlorophyll content, cell counts, and PE when exposed to dispersant-only solutions and Chemically-Enhanced Water Accommodated Fraction solutions of oil & dispersant (CEWAFs). Furthermore, low temperatures and salinities increased the toxicity of the oil & dispersant CEWAFs. These results suggest that phytoplankton assemblages may have been impacted by the Deepwater Horizon oil spill, possibly reverberating into higher trophic levels that could have impacted Gulf of Mexico fisheries.
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Date Issued
2018-05-25
Identifier
fgcu_ETD_0242
Format
Document (PDF)
Toxicity of Oil from BP Deepwater Horizon Blowout on the Early Life Stage of Red Drum, Sciaenops ocellatus
Title
Toxicity of Oil from BP Deepwater Horizon Blowout on the Early Life Stage of Red Drum, Sciaenops ocellatus.
Creator
McEachern, Kelsey L.
Abstract / Description
On April 20, 2010, one of the largest offshore oil spills in history occurred with the blowout of the British Petroleum Deepwater Horizon (DWH) Macondo Prospect well. The well blowout and subsequent release of oil had the potential to impact the ecosystem of the Gulf of Mexico that harbors many significant resources. Accordingly, this study attempts to systematically evaluate and organize data, information, assumptions, and uncertainties regarding the DWH blowout using an ecological risk...
Show moreOn April 20, 2010, one of the largest offshore oil spills in history occurred with the blowout of the British Petroleum Deepwater Horizon (DWH) Macondo Prospect well. The well blowout and subsequent release of oil had the potential to impact the ecosystem of the Gulf of Mexico that harbors many significant resources. Accordingly, this study attempts to systematically evaluate and organize data, information, assumptions, and uncertainties regarding the DWH blowout using an ecological risk assessment approach. The analysis phase included toxicity tests of chemically enhanced water accommodated fraction (CEWAF) of MC252 crude oil and Corexit on the early life stages (ELS) of the red drum, Sciaenops ocellatus. The objectives of this study were threefold: (1) to characterize the toxicity of CEWAF of MC252 crude oil to red drum ELS, (2) determine how the sensitivity of this species compares to other finfish ELS; and (3) to determine if these laboratory results might be used to predict effects from in situ exposure to other commercially, recreationally and ecologically important finfish in the wake of the DWH blowout. Red drum ELS exposed for 24 hours to CEWAF with total polycyclic aromatic hydrocarbons (PAHs) ranging from 0.25 mg/L to 5.5 mg/L presented with one or more gross abnormalities including: cardiac edema, skeletal abnormalities, yolk sac edema, finfold abnormalities and decreased growth. The median concentration at which 50% of the red drum larvae experienced abnormalities (EC50) and were considered non-viable after 24 hour exposure to CEWAF ranged from 0.38 mg/L to 1.63 mg/L (n=2). The median lethal concentration (LC50) ranged from 0.48 mg/L to 2.43 mg/L (n = 2). The results of this study are in agreement with other toxicity tests using various finfish ELS native to the GOM, and show that the effects of MC252 CEWAF toxicity can be debilitating to individual finfish ELS. Population level effects to red drum and other sensitive finfish as a result of the DWH blowout would be dependent on the spatiotemporal severity of exposure particularly in relation to the timing of natural density-dependent population regulation.
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Date Issued
2014
Identifier
McEachern_fgcu_1743_10083
Format
Document (PDF)