Task E. Bathyal Benthic Fauna and Sedimentary Dynamics – Understand Team Title: The Status of Bathyal Benthic Communities near the bp macondo Prospect
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- Megafauna Task.
- Macrofauna Task.
- Microfauna Task.
- Budget Overview. Megafauna and sediment analyses. – $ 47,080 Macrofauna analyses. – $ 34,775 Microfauna analyses. – $ 21,400
- Total Requested. – $ 235,000 References.
| Task E. Bathyal Benthic Fauna and Sedimentary Dynamics – Understand Team
Title: The Status of Bathyal Benthic Communities near the BP Macondo Prospect. Harriet Perry, Donald Johnson, Richard Waller – Megafauna Chet Rakocinski, Richard Heard – Macrofauna Charlotte Brunner – Microfauna - Benthic Foraminifera Oil pollution can devastate the sea floor by causing major disruptions to biogeochemical processes. Oil can cause selective and even mass mortality of the benthic meio-, macro-, and mega-fauna (Olsgard and Gray, 1995; Montagna and Harper, 1996; Yanko et al., 1999; Ernst et al., 2009; Martínez-Colon et al., 2009), either directly by surface coating or hydrocarbon toxicity (i.e., Gomez-Gesteira and Dauvin, 2005), indirectly by overloading the system with organic carbon and driving enhanced microbial respiration, or by shutting down ventilation of coastal waters, leading to the rapid development and persistence of hypoxic or anoxic conditions at and above the sea floor. Additionally, reductions in benthic biomass will reduce physical mixing of the sediment by suppression of the major bioturbators. Because benthic environments of the continental margin are highly productive, it is absolutely critical that the supply, impacts and fate of petroleum hydrocarbons on the benthos be quantified, as immediate ecological changes are expected and are likely to result in long term, ecosystem-scale adjustments throughout the water column. The benthic subsystem plays a pivotal role in the regeneration, transformation, and transfer of energy and nutrients through various benthic–pelagic coupling mechanisms involving both biogeochemical and biotic processes in marine and estuarine ecosystems (Twilley et al., 1999). Macrobenthic communities mediate the functioning of the benthic subsystem in ways that affect rates, directions, and pathways of exchange of energy and nutrients between the water column and the sediment (Hansen and Kristensen, 1997). Furthermore, disruption of benthic function through environmental degradation causes redirection and loss of macrobenthic trophic transfer potential to microbial pathways (Diaz and Rosenberg, 2008). Sediment contamination poses one of the most serious forms of environmental degradation within marine and estuarine ecosystems (Diaz and Rosenberg, 1996). Macrobenthic communities are ideal indicators of biotic integrity for many reasons (Rakocinski et al., 1997): (1) benthic organisms reside directly on or within sediments, where many contaminants are ultimately partitioned; (2) because benthic organisms are relatively sedentary, they cannot easily avoid contaminants; (3) the macrobenthos occurs on the proper spatial scale for assessing anthropogenic impacts; and (4) the temporal scale of macrobenthic organism life histories enables the detection of chronic or historical environmental stress through signature effects on resident assemblages. Because individual benthic taxa vary in their sensitivities to different contaminants, integrated responses by macrobenthic assemblages reflect the severity and nature of environmental stressors. Anthropogenic-related changes in macrobenthic assemblage structure also reflect concomitant shifts in ecosystem function through changes in trophic structure, the diversity of functional traits, and process indicators, like production potential, community turnover rates, and biomass-size spectra (Rakocinski and Zapfe, 2005). Benthic foraminifera are dominant members of the meiofauna at bathyal/abyssal depths, frequently exceeding other meiofauna in biomass, biovolume and biodensity (Coull et al., 1977; Cornelius and Gooday, 2004; Bernhard et al., 2000). For this reason, foraminifera are used here as an indicator of the condition of the meiofauna in general. Foraminifera have been shown to be responsive indicators of pollution, including oil contamination (Yanko et al., 1999; Ernst et al., 2009), exhibiting signs of ill-health such as declining species diversity, declining standing stock, assemblage changes, shallowing of infaunal habitation depths, declines in biomass, and increases in test deformities (survey article by Martínez-Colon et al., 2009). Their utility is enhanced by baseline reports on living foraminiferal populations in the Gulf sampled before the spill (Phleger and Parker,1951; Parker, 1954; Reynolds, 1982; Sen Gupta and Aharon, 1994; Sen Gupta et al., 1997; and Robinson et al., 2004; Bernhard et al., 2005). Deep-sea megafauna are defined as organisms large enough to be determined on photographs or taken in gear with a mesh size greater than 3 cms. They comprise a major fraction of the benthic biomass, play a key role in transfer of organic matter and are major bioturbators of bottom sediments. Prior to the oil spill, the deep-sea red crab (Chaceon quinquedens) was the primary inhabitant of the continental slope of the northern Gulf of Mexico (nGOM) and was perhaps the major bioturbator of the slope ecosystem. These crabs inhabit soft bottom areas and continuously filter fine sediment particles that are present in the bottom muds and the section of the water column immediately adjacent to the sediment-water interface, and thus would be expected to provide a useful diagnostic of organismal exposure to oil contamination of deep sea sediments. The center of abundance of red crabs in the eastern and northern GOM was located ~12 miles north of the wellhead. Following the oil spill, these organisms were much reduced or absent from two of the sites sampled in previous years and the giant deep-sea isopod, Bathynomus giganteus, was abundant. The GCRL has an extensive historical database defining geographic and bathymetric distribution and abundance of these crabs and data on heavy metals present in tissues of red crabs from the nGOM. Sites trapped in NGI Phase 1 indicate a change in community structure at the depths sampled. Completion of analytical work on red crab tissues collected will provide data on exposure to oil contamination. The proposed study would trap over the known range of the species in the nGOM to determine if the crabs had moved down-slope in response to the oil spill or suffered mortalities as a result of the spill. Approach. This study represents a collaborative effort comprised of three interrelated projects designed to assess benthic fauna as ecological indicators of the health of the bathyal benthic system at several levels of organization relative to the BP oil spill incident. To maintain continuity with previous studies, sampling will be conducted during August or September 2011 using the USM GCRL research vessel, the R/V Tommy Munro. Red crabs, sediment, and dissolved oxygen will be sampled in Areas 1and 2 at depths of 677, 860, 1043, and 1830 meters to determine current bathymetric distribution. Seven commercial plastic crab traps (Fathoms Plus®) will be fished on 366m of anchored ground tackle with a buoy line at a two to one scope. Traps will be baited with Gulf menhaden, Brevoortia patronus and fished for ~ 18 hours. Upon retrieval of the trap line the contents of each trap will be separated. Two adult males and two adult females from the set will be randomly selected for dissection and tissue analysis. Crabs for analysis will be maintained alive in refrigerated seawater systems at 5C and 36‰ salinity until they are dissected. Carapace width (CW) and carapace length (CL) will be measured (± 1 mm) for each crab. Crabs will be weighed and dissected on a glass dissection tray using high grade stainless steel scissors. Samples of gill, muscle, hepatopancreas, ovary and eggs (ovigerous females) will be removed for analysis of hydrocarbons,and dispersants. Bottom sediments will be taken with an Ocean Instruments MC800 multicorer, which simultaneously samples 8 replicate cores 9.5 cm by ~70 cm with an intact sediment-water interface. Companion Capetown dredge benthic samples will also be taken. Bottom-water samples will be taken using a rosette sampler in concert with a CTD equipped with temperature, salinity, depth, and dissolved oxygen sensors. Megafauna Task. Changes in slope community structure were apparent in the 2010 re-survey. Sampling was limited to a single depth stratum and it is not known if the red crabs shifted their distribution geographically or bathymetrically in response to the oil spill. The GCRL has trapped at 1000 fathoms in Area 1 and taken red crabs so it is possible that they may have traveled down-slope in response to the oil spill. The proposed study would re-survey areas previously sampled in September 2010 and would trap in deeper waters to see if red crabs have shifted their bathymetric distribution. Analysis of levels of hydrocarbons, dispersants, and heavy metals in red crab tissues in concert with changes in known distribution will provide information on the impact of oil on northern Gulf populations. Additional information on macrofaunal abundances will also provide an indication of food resource availability for red crabs. Crabs in Areas 1 and 2 would have the greatest potential for exposure over their geographic range. Macrofauna Task. Concomitant changes in the slope macrofaunal community in connection with the megafauna and microfauna will provide effective indicators of possible chronic effects of the DwH spill. In October 2010, companion Capetown dredge samples of bottom sediments were taken and processed for macrofauna in three established bathyal areas where megafauna were also trapped. These samples are currently being processed. Samples from the area where red crabs were captured contain a wide assortment of polychaetes, crustaceans, and larger foraminferans (>500 μm), which could also serve as food for red crabs. During Phase 2 of funding, we propose to continue joint sampling of benthic macrofauna in conjunction with megafaunal and extended microfaunal sampling along the slope where red crabs may occur. Sampling of benthic macrofauna will be extended in two ways during Phase 2 of this project: (1) In addition to qualitative Capetown dredge samples for characterizing the macrofaunal community and the relative abundances of the faunal constituents, three or four quantitative 9.525 cm diameter cores obtained by a multicorer device will be obtained for density and biomass estimates of the numerically dominant macrofaunal taxa; and (2) Sampling intensity will be extended to 8 sites distributed across the two megafaunal sampling areas, as described above. Microfauna Task. Changes in the benthic foraminifer community will be examined and compared to those in the mega- and macro-fauna to monitor signs of ecological distress. Although no foraminiferal samples were taken from these stations during phase 1(except for specimens >500 μm), samples of live benthic foraminifera were taken in October 2010 at sites nearby and at depths close to those discussed herein. In Phase 2, samples will be taken from the same multicorer casts as those used for macrofauna analysis, assuring spatial and temporal correspondence. Cores will be sliced into 1-cm slabs from the surface to 10 cm, stained with rose Bengal to tag specimens that are living or recently living (Bernhard, 2000), and washed on a screen of 63 μm. The sand-size residue will be buffered with sodium borate and stored wet in alcohol until a census of stained individuals is made. Budget Overview. Megafauna and sediment analyses. – $ 47,080 Macrofauna analyses. – $ 34,775 Microfauna analyses. – $ 21,400 Ship Time (6 d @ 7K per d) – $ 42,000 Direct Costs (not incl Ship Time) – $ 103,255 Indirect Costs (@ 46.5% of Direct) – $ 89,745 Total Requested. – $ 235,000 References. Bernhard, J.M., 2000. Distinguishing live from dead foraminifera: methods review and proper applications. Micropaleontology 46 (Suppl. 1), 38–46. Bernhard, J.M., Buck, K.R., Farmer, M.A., Bowser, S.S., 2000. The Santa Barbara Basin is a symbiosis oasis. Nature 403 (6765), 77–80. Coull, B.C., Ellison, R.L., Fleeger, J.W., Higgins, R.P., Hope, W.D., Hummon, W.D., Rieger, R.M., Sterrer, W.E., Thiel, J., Tietjen, J.H., 1977. Quantitative estimates of the meiofauna from the deep sea off North Carolina, USA. Marine Biology 39, 233–240. Cornelius, N., Gooday, A.J., 2004. ‘‘Live’’ (stained) deep-sea benthic foraminiferans in the western Weddell Sea: trends in abundance, diversity and taxonomic composition along a depth transect. Deep-Sea Research II 51, 1571–1602. Diaz, R. J., and R. Rosenberg. 1996. The influence of sediment quality on functional aspects of marine benthic communities. Pages 57-68 in M. Munawar and G. Dave, editors. Development and progress in sediment quality assessment: rationale,challenges, techniques and strategies. Ecovision World Monograph Series. Academic Publishing, Amsterdam, The Netherlands.
Gomez-Gesteira, J.L.and J.-C.Dauvin, 2005. Impact of the Aegean Sea oil spill on the subtidal fine sand macrobenthic community of the Ares-Betanzos Ria (Northwest Spain). Marine Environmental Research 60: 289–316.Hansen, K. and E. Kristensen. 1997. Impact of macrofaunal recolonization on benthic metabolism and nutrient fluxes in a shallow marine sediment previously overgrown with macroalgal mats. Estuarine, Coastal, and Shelf Science 45:613–628. Martínez-Colon, M., Hallock, P., and Green-Ruíz, C., 2009. Strategies for using shallow-water benthic foraminifers as bioindicators of potentially toxic elements: a review. Journal of Foraminiferal Research, 39(4): 278-299. Montagna, P.A. and D.E. Harper. 1996. Benthic infaunal long-term response to offshore production platforms in the Gulf of Mexico. Can. J. Fish. Aquat. Sci. 53: 2567–2588 Olsgard, F. and J.S. Gray. 1995. A comprehensive analysis of the effects of offshore oil and gas exploration and production on the benthic communities of the Norwegian continental shelf. Marine Ecology Progress Series (Mar Ecol Prog Ser) 122: 277-306. Parker, F.L., 1954. Distribution of the Foraminifera in the northeastern Gulf of Mexico. Bulletin of the Museum of Comparative Zoology, Harvard College 111 (10), 453–588. Phleger, F.B., Parker, F.L., 1951. Ecology of Foraminifera, northwest Gulf of Mexico. Geological Society of America Memoirs 46 (Parts I and II), 88+64pp. Poag, C.W., 1981. Ecologic Atlas of Benthic Foraminifera of the Gulf of Mexico. Marine Science International, Woods Hole, MA, 175pp. Rakocinski, C.F., Zapfe, G.A., 2005.Macrobenthic process indicators of estuarine condition. In: Bortone, S.A. (Ed.), Estuarine Indicators. CRC Press, Boca Raton, pp. 315–331. Rakocinski, C. F., S. S. Brown, G. R. Gaston, R. W. Heard, W. W. Walker, and J. K. Summers. 1997. Macrobenthic responses to natural and contaminant-related gradients in northern Gulf of Mexico estuaries. Ecological Applications 7:1278–1298.Reynolds, L.A., 1982. Modern benthic foraminifera from the Gyre intraslope basin, northern Gulf of Mexico. Gulf Coast Association of Geological Societies Transactions 32, 341–351. Robinson, C.A., Bernhard, J.M., Levin, L.A., Mendoza, G.F., Blanks, J.K., 2004. Surficial hydrocarbon seep infauna from the Blake Ridge (Atlantic Ocean, 2150 m) and the Gulf of Mexico (690–2240 m). Marine Ecology 25 (4), 313–336. Sen Gupta, B.K., Aharon, P., 1994. Benthic foraminifera of bathyal hydrocarbon vents of the Gulf of Mexico: initial report on communities and stable isotopes. Geo-Marine Letters 14, 88–96. Sen Gupta, B.K., Platon, E., Bernhard, J.M., Aharon, P., 1997. Foraminiferal colonization of hydrocarbon-seep bacterial mats and underlying sediment, Gulf of Mexico slope. Journal of Foraminiferal Research 27 (4), 292–300. Twilley, R. R., J. Cowan, T. Miller-Way, P. A. Montagna, and B. Mortaavi. 1999. Benthic nutrient fluxes in selected estuaries in the Gulf of Mexico. In Biogeochemistry of Gulf of Mexico Estuaries, T. S. Bianchi, J. R. Pennock, and R. R. Twilley (eds.). John Wiley & Sons, New York, pp. 163–209. Yanko, V., Arnold, J.J., and Parker, W.C., 1999. Effects of marine pollution on benthic foraminifera, In: Sen Gupta, B. (ed.), Modern Foraminifera, Kluwer, Boston, p. 217-235. Directory: pub -> eric -> BP%20NGI%20Phase%20II -> USM -> Understand pub -> Acm word Template for sig site pub -> The german unification, 1815-1870 pub -> Baltic Olympiads in Informatics: Challenges for Training Together pub -> Preparation of Papers for ieee transactions on medical imaging pub -> Forthcoming meetings and conferences pub -> Asilomar Conference on Circuits, Systems & Computers, Pacific Grove, ca, November 1978, pp. 55 58 pub -> Forthcoming meetings and conferences pub -> Harmonised compatibility and sharing conditions for video pmse in the 7 9 ghz frequency band, taking into account radar use Understand -> Fundulus grandis and selection for pah-resistant genotypes along the Gulf Coast Download 30.02 Kb. Share with your friends:
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