Abstract:
A mesocosm experiment was conducted at the Dauphin Island Sea Lab during March 2017 to evaluate the effects of the water accommodated fraction (WAF) of oil on animal behavior, bioturbation, and sediment oxygen demand. We exposed two infaunal taxa, the polychaete, Owenia fusiformis, and the brittle star, Hemipholis elongata, to sublethal concentrations of WAF in infaunal assemblages of both mixed and single-species. Data on animal feeding behavior, bioturbation, sediment water content, and sediment oxygen demand are included.
Suggested Citation:
Kelly Dorgan, Erin Kiskaddon. 2019. Sublethal effects of oil exposure on infaunal behavior, bioturbation, and sediment oxygen consumption: a mesocosm experiment. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/6B9VS3FK
Data Parameters and Units:
The dataset contains data organized under seven different worksheets: “AnimalSurvival”, “LuminiphoreMaxDepth”, “LuminiphoreCoverage+Porosity”, “FeedingAreas”, “Feces”, “O2Flux”, and “HorizontalLuminiphoreDispersion”. The contents of all the worksheets are defined below:
The worksheet “AnimalSurvival” contains: MesoID (mesocosm identification), Tub (Tub # 1-10), Community (organism and density), Taxa (organism present), Exposure (describing whether oil was added), Initial # animals, Recovered # animals, and Proportion recovered.
The worksheet “LuminiphoreMaxDepth” contains: Tub (Tub # 1-10), Exposure (describing whether oil was added), Treatment (refers to the type and density of organism that was added or control), and Max depth of luminophores (cm).
The worksheet “LuminiphoreCoverage+Porosity” contains: MesoID (mesocosm identification), Tub (Tub # 1-10), Treatment, Taxa, Depth (cm), Sediment Pixels, Luminophore.Pixels, Percent luminophore cover, and Water content (g water/g wet wt).
The worksheet “FeedingAreas” contains: Treatment (whether WAF is present or not), Tub (Tub # 1-10), {measurements of the size of feeding made at different dates - FeedingArea.14mar (mm^2), FeedingArea.17mar (mm^2), and FeedingArea.26mar (mm^2)}.
The worksheet “Feces” contains: Treatment (whether WAF is present or not), Tub (Tub # 1-10), and quantification of feces at different dates - Feces #_Mar9, Feces #_Mar14, Feces #_Mar 17, Feces #_Mar 26, and Feces #_Mar 30.
The worksheet “O2Flux” contains: Sampling Day, Tub (Tub # 1-10), Week, Run, Taxa (describes which organism or combination of organisms or control is present), Treatment (whether WAF is present or not), and Oxygen Flux (mmol O2 m-2 d-1).
The worksheet “HorizontalLuminiphoreDispersion” contains: Depth (cm), Treatment (describing organism present), Exposure (whether WAF is present or not), Tub (Tub # 1-10), Radius, r (cm), and Ripley's K.
Please note - OWE = Owenia fusiformis monoculture; BS = brittle star, Hemipholis elongate monoculture; HDM(BS) = High-density monoculture of brittle star, Hemipholis elongate; HDM(OWE) = High-density monoculture of Owenia fusiformis monoculture; LDM(BS) = low-density monoculture of brittle star, Hemipholis elongate; LDM(OWE) = Low-density monoculture of Owenia fusiformis monoculture; WAF = Water-accommodated fraction; CON = control; LDMix = Low-density mixture of cultures; HDMix = high-density mixture of cultures.
Methods:
Mesocosm Setup: Two parallel recirculating systems – one with WAF and one without – were constructed in an outdoor mesocosm facility at the Dauphin Island Sea Lab, Dauphin Island, AL, in spring 2017. For each system, five replicate tanks were plumbed together in series to create a single flow-through system, filled with filtered seawater from the Gulf of Mexico. An in-line pump (Iwaki MD-40 single phase induction motor capacitor) circulated water. Each tank with each system was separately oxygenated using air stones to ensure full oxygen saturation and to guard against any malfunction in the circulation system (although no malfunctions occurred). Each tank was also covered with a translucent plastic lid to reduce evaporative water loss while still permitting ambient light exposure. All tanks for both the WAF and control systems were partially submerged in seawater in a single 2.4 m diameter tank to minimize temperature fluctuations.
WAF was made in the laboratory using MC252 Reference Material, oil with a chemical composition similar to that of Macondo oil released during the DWH oil spill. Oil was obtained from the BP Gulf Coast Restoration Organization (GCRO) (request ID: 18480). Crude oil was combined with filtered seawater (1:10) and shaken on an outdoor shake table at 108 rpm for 72 hours under ambient sunlight. This facilitated photo-oxidation and simulated turbulent mixing. The surface layer of crude oil was then removed using a separatory funnel and discarded, and the underlying water was frozen at -4°C until being used in the experiment.
Five community treatments were exposed in mesocosms to seawater contaminated with WAF versus uncontaminated seawater for 24 days in March 2017. The community treatments were Owenia fusiformis monoculture, Hemipholis elongata monoculture, a low-density, substitutive combination of both species, a high-density, additive combination of both species, and control without animals. We measured O. fusiformis feeding behavior using the area of its feeding pits and the number of defecation mounds (similar metrics were not possible for H. elongata). We quantified bioturbation in monocultures of both taxa and mixed faunal treatments by measuring the vertical and horizontal distribution of luminophore tracer particles at the end of the experiment (Solan et al. 2004). Other mesocosm metrics of sediment water content and animal survival are also included. Lastly, we measured sediment oxygen demand at the beginning, middle, and end of experiments using custom-built metabolism chambers.
Provenance and Historical References:
Solan, M., Wigham, B., Hudson, I., Kennedy, R., Coulon, C., Norling, K., … Rosenberg, R. (2004). In situ quantification of bioturbation using time-lapse fluorescent sediment profile imaging (f-SPI), luminophore tracers and model simulation. Marine Ecology Progress Series, 271, 1–12. doi:10.3354/meps271001
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