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Impact of Crude Oil on Coastal and Ocean Environments of the West Florida Shelf and Big Bend Region from the Shoreline to the Continental Shelf Edge

    

    

Description

The oil gushing from the Deepwater Horizon accident is having significant effects on the ecology and economies of the Gulf of Mexico, impacting both ecological and human communities for decades to come. The overall effect is difficult to predict for two reasons. First, critical baseline data are lacking to adequately distinguish effects of the oil from normal temporal and spatial variation in species abundances. Long-term data especially are generally lacking; this is a common problem that has plagued evaluations of the effects of the Exxon Valdez spill (Guterman 2009). Separating natural patterns from dynamics caused by pollution from oil spills is particularly problematic for coastal communities in the GOM, where hurricanes can cause dramatic "natural" variation across ecosystems. Second, historical studies of oil spills have been relatively short-term; the post-spill studies of the Exxon Valdez are the exception. Generally, a great deal of attention is given to the immediate effects on birds and other, often charismatic, wildlife and there is a significant concern about effects on fisheries. However, much less attention is given to the ecology of coastal areas, where much of the un-reclaimed oil eventually resides and where effects can be slow and long-lasting, and virtually none is given to shallow-water reefs, shelf edge, slope, or deep sea. All of these habitats provide critical ecosystem services that will be impaired by the presence of oil. Recovery times for these habitats will vary. Thus, it is critical that we identify those factors contributing to recovery to ensure that there is intense focus on remediation and restoration efforts in affected areas to help restore ecological services and therefore economic wellbeing. Any remediation following from the spill requires a quantitative assessment of the processes that control uptake, degradation and release of crude oil components.

The project developed by Florida State University in response to this spill represents an integrated, rapid-response study of the impact of oil on coastal and ocean marine ecosystems of the northeastern Gulf of Mexico (NEGOM), including the northern West Florida Shelf (WFS) from the Big Bend Region (BBR) west to Louisiana, that can be completed in its entirety within 5 months. The physical modeling and ecological teams assembled here are uniquely disposed to address this issue because of the coordinated efforts already underway since the inception of the NGI both within and external to NGI member institutions, and the long-term baseline datasets developed by a number of FSU researchers. The objectives of this proposal are to improve the modeling physical parameters that influence the distribution and persistence of oil; to examine the effects of oil deposition on biogeochemistry and the direct and indirect consequences to coastal habitats (including beach-dune-swale, saltmarsh, nearshore sponge-soft coral reef, and offshore reef fish spawning habitats) and marine foodwebs that support fishery production; and to determine the ecological considerations needed to inform rapid bioremediation.

Goals

  • To improve the modeling and tuning of the physical parameters that influence the distribution and persistence of oil;
  • To examine the effects of oil deposition on GOM coastal habitats, including:
    1. Beach sediment biogeochemistry and the ecology of resident meiofauna
    2. Direct and indirect effects on beach-dune-swale plant complexes
    3. The effects of species diversity, consumer pressure, and bioremediation on salt marsh habitat
  • To examine the impact on fisheries, including:
    1. The impact on shallow-water reefs that act as secondary nursery habitat
    2. The impact on shelf-edge spawning habitat
    3. The impact on marine food webs that support fishery production

Project Tasks:

Task 1 : Oil & Layers on the Ocean: Impacts of Capillary Wave Damping on Remote Sensing & Air-Sea Fluxes (Bourassa, Chassignet, Dukhovskoy, Garcia, McDonald, Morey)Abstract: Oil raft from the Deepwater

  • Abstract : The modeling group proposes to investigate how oil and similar surface microlayers of differing thicknesses damp capillary waves that can be measured by satellite microwave radar (principally synthetic aperture radar – SAR), and alter the wind stress (and thus thermodynamic fluxes) at the ocean surface. This proposed work will use satellite remote sensing, in situ sampling, and numerical modeling of isolated nearshore rafts of oil (Figure 1). Results will have immediate broader impacts on identification, tracking, and forecasting of the oil slick to aid in response to the disaster, as well as provide a better understanding to the scientific community of the dynamics of the ocean in the presence of a surface microlayer.
  • Objectives:

    • To determine the impact of oil and other similar surface microlayers (e.g. surfactants) on capillary wave damping, and how this changes with differing thicknesses and composition of the microlayers.
    • To understand how the surface oil modification of capillary waves affects SAR microwave backscatter used for oil detection and for measuring surface fluxes.
    • To make preliminary estimates of how surface oil impacts air-sea fluxes of heat and momentum, the dependence on wind speed, and impacts on the subsurface thermodynamic properties of the ocean.
  • Deliverables:
    • 1. SAR and scatterometer estimates of oil location and surrounding wind speeds
    • 2. Initial estimate of wind speeds threshold for capillary wave dampening, as function of surface oil characteristics
    • 3. Preliminary model tuning to better match these observations

Task 2 : Effects of Oil Deposition on Coastal Sand, Beach, Dune, and Salt Marsh Environments (Huettel, Hughes, Kimbro, Kostka, Miller)

Background: We propose a three-phase approach to understanding these impacts by conducting quantitative analyses of the impacts of oil contamination on the ecology of indigenous microbial communities and macrofauna in beach sands, dune vegetative communities, and saltmarsh communities. This is clearly a prerequisite for minimizing the environmental consequences of oil spills and optimizing the environmental benefits of biodegradation

  1. Task 2a: Microbial analysis of sandy sediments
    • Abstract: The PIs for this component have conducted research in sandy nearshore environments in Florida for 6 years and have accumulated data on sediment characteristics (Wilson et al. 2008), sedimentary metabolic processes (Gihring et al. 2009, Gihring et al. 2010), sediment-water exchange of solutes (Berg and Huettel 2008, Chipman et al. 2010) and the microbial community in the sands (Hunter et al. 2006, Mills et al. 2008). This experience clearly supports the rapid response work necessary for this study and interpretation of the results.
    • Objectives:
      • To determine how much oil is filtered into NEGOM sandy beach sediment and how this oil alters sediment characteristics,
      • To determine how the oil changes structure and function of the sand faunal and microbial communities
      • To determine which factors regulate oil degradation in marine sands.
    • Deliverables:
      1. Data on the amount of oil that is filtered into NEGOM sandy beach sediment;Data on how this oil alters sediment permeability
      2. Data on the difference in fauna of polluted and unpolluted beaches
      3. Data on the microbial community composition of beach sands with and without oil
      4. Data on oil degradation rates in the sand
  2. Task 2b: Direct and indirect effects of oil on coastal dune vegetation and microbial communities
    • Abstract: FSU researchers have the only long-term database on coastal dune vegetation in the GOM. Their study of St. George Island since 1998 across a variety of habitats demonstrates that dunes exhibit tremendous inter-annual variation in response to climate, undergoing complex changes through time (Figure 2), with accompanying changes in the geomorphology that are correlated with constant forces (normal wave action, winds, and sea-level rise) and less predictable extreme disturbances (droughts and storms). These data can be used to quantify the effects of specific disturbances, such as storms, on the plant communities (Miller et al. 2010) and to make first order predictions about future changes (Gornish and Miller 2010), including those effected by oil.
    • Objectives:
      • To extend ongoing surveys in this habitat to quantify the effects of oil across dune features;
      • To include measures of oil in the soil and effects of oil and oil by-products on soil microbial activity;
      • To increase the spatial extent of the study across the NEGOM to document the effects of oil.
    • Deliverables:
      1. Due to the prior long-term data, the St. George vegetation results will allow us to clearly identify effects of oil on sandy coastal habitats. The long-term data are already available at http://www.bio.fsu.edu/~miller/ HOMEPAGE/research.html.
      2. The oil and soil analyses will identify causal factors, demonstrating the direct and indirect mechanisms by which the oil spill may affect sandy coastal vegetation.
      3. Sampling at other locations around the Gulf can first be calibrated using the St. George analyses and local climate data. These sites can then be used to demonstrate the larger scale effects of oil, presumably over a gradient of oil exposure.
  3. Task 2c: Effects of species diversity, consumer pressure, and bioremediation on salt marsh recovery from oil.
    • Abstract: In this portion of the study, the PIs will examine the independent and interactive effects of plant species diversity, consumer presence, and bioremediation (nutrient addition) on the recovery of salt marsh systems from oil / hydrocarbon exposure.
    • Objectives:

      • Quantify relationships between plant species diversity, community structure, and response to oil exposure in natural salt marshes ranging from St. Joe Bay to Cedar Key, FL, and
      • Experimentally test the relative importance of plant species diversity, consumer presence, and bioremediation via nutrient additions on the recovery of salt marshes across this same geographic region.
      • We hypothesize that marsh recovery will be greatest under the following conditions: (1) high plant species diversity; (2) low consumer abundance; and (3) high sediment nutrient availability. We will test these hypotheses via surveys and experiments to quickly provide information for marsh remediation and restoration.
    • Deliverables:

      1. Data on pre- and post-oil salt marsh community structure (e.g., plant biomass, plant species diversity, animal abundance, animal species diversity) across the Panhandle and Big Bend of FL
      2. Data on pre- and post-oil hydrocarbon levels incorporated into marsh sediments along this geographic gradient
      3. Data on the effectiveness of consumer removals and/or nutrient additions for counter-acting oil impacts to salt marshes
      4. Data on the role of salt marsh plant species diversity in recovery / immediate restoration success

Task 3: Examining the Impact of Oil on Essential Fish Habitat and Food Webs (Chanton, Coleman, Craig, Huettel, Koenig, Stallings)


Background: Fisheries managers have long understood the strong correlation between habitat quality and fisheries productivity (Dayton et al. 1995, Arthur et al. 1996, Langton et al. 1996), but none could have imagined the potential effects of an oil spill the magnitude of the DwH. Critical to our understanding the effects of the spill on fishery production is knowledge of the essential fish habitat that supports that production and of the pathways through which oil contamination moves from the physical habitat through biological communities. Understanding the impact of oil deposition on essential fish habitat is critical for determining the long-term ecologic and economic consequences, which we expect could be profound.
The intent is to evaluate whether or not an impact has occurred, which components are affected, and determine the magnitude of change. In all habitats studied, sediment analyses will determine the level of the contamination. The level of the impact is determined from the community response. We evaluate the transmission through the food web by characterizing responses in organisms at different trophic levels. While there is not sufficient time nor support for determining what mitigating factors affect these communities, we can obtain a snapshot of occurrences.

  1. Task 3a: Effects of oil contamination on shallow coral/sponge-dominated reefs.
    • Abstract: Biologically diverse coral/sponge-dominated rocky habitat common throughout the shallow (10–30 m) waters of the NEGOM, provides spawning and nursery habitat for many economically important fishery species (e.g., groupers, snappers, stone crabs) and is being evaluated currently by NGI investigators. While its contribution to ecosystem services is high, basic habitat mapping and characterization is in its infancy. Our archived video-based data taken over the last few years provides baseline data for comparison with reef conditions after impacts from crude oil contamination. Additional reefs, selected from our sidescan sonar surveys along depth gradients, provide site-specific data for documentation of changes relative to degrees of oil contamination.
    • Objectives:
      • To conduct video surveys at historically-documented sites emphasizing biological community parameters (distribution/abundance patterns, species richness and composition, size structure, etc.).
      • To collect photographic and video records at permanent stations on replicated reefs at 10, 15, 20 m depths so that communities and individual sessile organisms can be tracked through time.
      • To map surveyed coral/sponge habitats using GIS to link geologic, geographic and biological habitat features with depth and degree of oil contamination.
      • To quantify the oil contamination in sediments and representative organisms at each reef site.
    • Deliverables:
      1. Data on the level of oil contamination of sediments, fish, and invertebrate samples from multiple reefs in the northern Big Bend region,
      2. Data on ecological community parameters and individual coral and sponge condition relative to degrees of oil contamination on: (1) reefs previously surveyed, then resurveyed and (2) replicate reefs selected from multiple depths.
      3. GIS maps of surveyed reefs incorporating all collected information on geological, biological and contamination characteristics.

  2. Task 3b: Potential for crude oil pollutants to concentrate in shelf-edge habitat engineered by fishery species
    • Abstract : Red grouper (Epinephelus morio) act as ecological engineers to enhance and maintain biologically-diverse communities across the continental shelf to the shelf edge (Coleman and Koenig 2010, Coleman et al. 2010). On the NEGOM shelf edge, they construct in carbonate sands cone-shaped excavations (pits, 6 m across, 2 m deep), the areal density of which in Steamboat Lumps Marine Reserve is about 250 per km2 (Scanlon et al. 2005)(Figure 3) and the biological diversity of which is significantly greater than that in the surrounding environment. Pits are used as refugia by planktivorous fishes that forage in the upper water column and deposit feces in and around the pits thereby coupling pelagic and benthic environment through trophic energy transfer; by sessile invertebrates as settlement sites; and by several other fishery species as nursery habitat. Thus, the grouper provides an important keystone role . This species also is highly productive and important in an economic sense because it supports roughly two-thirds of the entire grouper catch in the United States (Schirripa et al. 1999).

      Because of these dual roles, we are moved to investigate the impact of oil on these unique features. The pits act as natural sediment traps, and we suspect that they also accumulate crude oil particles that settle out from the water column or are transported by currents along the sea bed. The carbonate sand is sufficiently porous to act as a sponge, soaking up crude oil droplets that result from dispersant application. This enrichment, exacerbated by grouper digging activity, could change the physical and biogeochemical characteristics of the sand. For instance, by binding sand particles, the oil changes the size distribution of the sediment and the permeability of the sediment to water flow and O2 distribution, thereby decreasing aerobic degradation rates of imbedded oil. If bottom water flows are reduced in the protected environment of the pit, then toxic substances released during oil degradation could accumulate at higher concentrations in the pit compared to those in the surrounding environment. This could have a negative community-level effect by driving down diversity and abundance as toxic compounds accumulate.

      There may be direct population-level physiological impacts on red grouper, who come in direct contact with polluted sediment while transporting sediment from the center of the pit, the presumed zone of greatest contamination, to the pit edge, where they forcibly expel sediment through their mouth and gill chambers (Coleman et al. 2010). Gills are the site of maximum uptake of lipophilic compounds (Randall et al. 1998), such as oil-derived polynuclear aromatic hydrocarbons (PAHs), the bioaccumulation of which could cause reproductive failures by becoming incorporated into the lipids of the eggs or through deleterious effects on the process of vitellogenesis (Nicholas 1998).

      Presently there is no information available on the ability of grouper pits to act as oil traps, nor is their information on the level of uptake of contaminants in grouper and associated species in the shelf edge environment.
    • Objectives:
      • To quantify along a transect oil deposition, O2 consumption, DIC production rates, and influence of trapped oil on sediment physical and biogeochemical characteristics of sediments
      • To collect and freeze tissues (liver, muscle, gonad, and stored fat) and stomach contents of red grouper and associated species for eventual determination of the levels of oil contamination
      • To compare the biotic characteristics of red grouper pit communities from our historical video data with post-oil-spill data
    • Deliverables:
      1. Data on sediment oil content collected from grouper pits to determine if pits act as oil traps
      2. Data on O2 consumption and sediment characteristics of oiled and oil-free sediment taken along pit transects (Comparisons will show effects of oil on sediment metabolism and on grouper diggig).
      3. Data on macrofauna diversity in oiled and oil free sediment
      4. Data on diversity, abundance, and condition of fish associated with grouper pits.
      5. Fish and invertebrate samples for evaluation of levels of PAHs and other oil-derived contaminants


  3. Task 3c: Tracing the intrusion of the oil spill in GOM marine food webs with radiocarbon and stable isotopes
    • Abstract : The radioisotopic form of carbon, 14C, is a useful tool for investigating sources, transformations, and residence times of inorganic and organic carbon pools in terrestrial and marine ecosystems (Druffel et al. 1996, Bauer et al. 1998a, Cherrier et al. 1999, Chasar et al. 2000, Bauer et al. 2002, Mortazavi and Chanton 2004, Chanton et al. 2008). Living biomass is imprinted with a 14C signature which is set by carbon fixation from atmospheric CO2. This living biomass has slightly greater radiocarbon content than "modern" (0‰) due to nuclear weapons testing in the 1950's and 1960's which produced an abundance of 14C in the atmosphere). Currently this value is around +107% of modern, but it can significantly depart from this value in coastal waters due to variation in the importance of terrestrial inputs (Raymond and Bauer 2001a, 2001b), or upwelling of older deeper water including contributions for sediments (Druffel et al. 1996, Bauer et al. 1998a, 1998b, Bauer et al. 2002). Because of these factors, we cannot know current 14C values of living biomass a priori - it is necessary to quantify pre-impact 14C levels in organisms in the northern Gulf Coast.

    • Objective: The overall goal is to determine the impact of the oil/dispersant on the food web of the Gulf Coast using 14C and stable isotope (13C, 15N & 34S) analysis. Does carbon from the oil/dispersant enter the food web via microbial consumption and biomass production from oil/dispersant substrates and subsequent incorporation into the food web (e.g., the microbial loop)? Or through more direct means, perhaps entering via filter and deposit feeding organisms? Our long term objective is to determine the 14C and stable isotopic (C, N, S) content of biomass, particulate organic carbon (POC), and sedimentary organic matter, prior to, during, and following the full impact of petroleum residues across this region. The pre-impact values will then be compared to post impact values across this spatial gradient to determine the route and magnitude of oil effects on coastal food webs and fisheries.
      Stable isotope tracing is an excellent complement to our radiocarbon approach. The technique has been used for assessing carbon and nitrogen flow through aquatic ecosystems (Fry 1984, Peterson and Howarth 1987, Wilson and Burns 1996, Deegan and Garritt 1997, Chanton and Lewis 1999, Chanton and Lewis 2002, Chasar et al. 2005, Wilson et al. 2009, 2010 (In press)). The isotopic signatures of heterotrophic organisms reflect their assimilated substrates. The technique has been also been used to identify substrate sources supporting bacterial growth in marine systems. In addition to carbon stable isotopes, δ34S is a conservative tracer elucidating the contributions of various substrates including petroleum. Nitrogen stable isotopes are useful indicators of trophic position due to the 3± increase that occurs with each rise in trophic step.
      This project tests the hypothesis that oil/surfactant residues will enter the food web either directly by ingestion or via the microbial loop. The presence of these residues in biomass will be determined by examination of tissue 14C content assuming two end members, the contemporary 14C value of the tissue of each organism pre-impact and the radiocarbon free content of oil.
      • Radiocarbon content measured in affected organism post impact = Fm
      • Pre-impact radiocarbon content in same organism = Fp
      • Radiocarbon content of oil = 0
      • Fm = Fp(x) + (1-x) * 0
    • Deliverables
      1. The radiocarbon composition of organisms, particulate organic carbon and sedimentary organic carbon will be characterized pre-impact along the northern Gulf Coast from both recently collected and archived samples.
      2. The stable isotopic composition of organisms, particulate organic carbon and sedimentary organic carbon will be characterized pre-impact along the northern Gulf Coast from both recently collected and archived samples.
      3. Early Post-impact intrusion of petroleum and methane into the food web will be assessed.

Deliverables

See above for abstracts, objectives, and deliverables by tasks and sub-tasks.

Principal Investigators

Eric Chassignet, Center for Ocean-Atmospheric Prediction Studies, Florida State University

Mark Bourassa, Center for Ocean-Atmospheric Prediction Studies, Florida State University

Thomas Miller, Department of Biological Science, Florida State University

Collaborators and Partners

Center for Ocean-Atmospheric Prediction Studies, Florida State University
Department of Oceanography, Florida State University
Coastal and Marine Laboratory, Florida State University
Department of Biological Science, Florida State University
BP Gulf of Mexico Research Initiative, Non-Governmental Agency

For more information on this project, please contact the Program Office. A more detailed review of this project can be found in the NGI Documents.

For internal use only: Project No. 10-BP_GRI_FSU-01. Expiration Date: 12/31/2010.