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 OCS Scientific Committee Meeting Summary - Environmental
Studies Program Highlights - Gulf of Mexico OCS Region
Gulf of Mexico OCS Region Perspective. Mr. Oynes, Regional Director, gave an update on
shallow water and deep water activities including exploratory wells and new production as
well as the status of several environmental efforts including FPSO systems’ EIS’
and what environmental study contract results are due out in the next 1-2 years.
 | Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology Study. Dr.
Gilbert Rowe, Professor, Biological Section, at Texas A&M University and Program
Manager of the Study of Life on the Floor of the Gulf of Mexico, stated that the
exploration in the Gulf of Mexico for and commensurate production of fossil fuel deposits
are expanding rapidly from the continental shelf offshore across the continental rise into
depths of several thousand meters. Little is known of how this expansion might affect
potential fisheries resources at these depths. Knowledge of the structure of open-water
offshore biological communities on the sea floor of the Gulf of Mexico, where oil and gas
exploration is particularly intense, is restricted at the present time to a limited number
of rough estimates of species composition and abundances. The general patterns in the Gulf
of Mexico appear to be similar to other continental margins with several remarkable
exceptions. While the typical Gulf of Mexico bottom communities are depauperate in numbers
and biomass compared to comparable depths in many regions of the world, the slope is also
characterized by seep communities that receive their energy from fossil hydrocarbon
deposits that are leaking into the bottom water. It is a broadly held assumption that the
nature of communities is determined by the input of organic matter to the sea floor.
Mathematical models can be generated based on this principle to predict the amount of
biomass that can be supported in a bottom community, given enough information on surface
primary production, water depth, and the nature of the organic matter flux down to (or up
through) the bottom. In the present paper, several models are presented that contrast the
upper slope, where living resources are abundant with deep water where desert-like
conditions persist. Additional scenarios can be added to the models that mimic potential
effects from offshore platforms. Unfortunately, to date none of these models for the Gulf
of Mexico have been validated.
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| Effects of Oil and Gas Exploration and Development at Selected Continental Slope
Sites in the Gulf of Mexico. U.S. Department of the Interior, Minerals Management
Service - 2000 to Present. Dr. Alan Hart, Science Director
of Continental Shelf Associates, stated that Continental Shelf Associates, Inc., is
performing a multiyear study of "Effects of Oil and Gas Exploration and Development
at Selected Continental Slope Sites in the Gulf of Mexico." The objectives of this
study are to determine: 1) the physical impacts of the operations on the seafloor
including muds/cuttings accumulation, anchoring systems, and debris; 2) physical/chemical
modification of sediments; and 3) biological effects in the benthos and demersal fishes.
The study sites include three post-development sites (all drilling activities completed),
two exploration sites, and a single site where approximately 800 barrels of synthetic
based mud was spilled. Both water based and synthetic based muds were used in the drilling
of the development wells and will be used in the drilling of the exploration wells. The
development sites will be surveyed once. The exploration sites will be surveyed before and
after drilling and the spill site will be surveyed once. The post-development and
exploration sites are in approximately 1,000 meters water depths and the spill site is in
approximately 670 meters of water. The physical impacts will be determined using
deep-towed side-scan sonar/high resolution chirp sonar and acoustic reflectivity will be
mapped. The physical/chemical sediment environment will be sampled using a box core and
sediment profile imaging system. Sediment grain size, mineralogy, texture, radionuclides,
metals, total organic carbon, and hydrocarbons will be analyzed. Samples for pore water,
redox chemistry, and sediment toxicity (10-day acute test) also will be collected. The
biological community will be sampled using a box core, still photographs, and bottom
traps. A number of biological parameters will be measured: 1) microbiotal activity,
biomass, and community structure; 2) meiofauna including harpacticoid taxonomy/genetic
diversity/reproductive status and nematode feeding groups; and megafaunal taxonomy and
metal/hydrocarbon concentrations in tissues of selected animals. Interpretation and
synthesis of the data will include the testing of hypotheses concerning differences in
chemical and biological parameters between areas in the vicinity of exploration,
development, and spill sites and reference areas. The tests of hypotheses will provide
insight into the effects on the continental slope biota. A screening level ecological risk
assessment for the activities also will be performed.
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| MMS/NMFS Pilot Sperm Whale Study. Dr. Bill Lang, oceanographer, Gulf of Mexico
OCS Region, gave background information on the Pilot Sperm Whale Study which is a
cooperative research with the National Marine Fisheries Service (NMFS) initiated on June
27th to conduct studies on sperm whales and deepwater acoustics in the Gulf of
Mexico. Dr. Keith Mullin, Gulf Coast Research Laboratory, explained in detail the outcome
of a month-long pilot study cruise that was conducted from the National Oceanic and
Atmospheric Association’s research vessel Gordon Gunter. The cruise was
successful, far exceeding expectations. It was designed to test a variety of new equipment
and research methods directed at studying sperm whales in the Gulf of Mexico and to
characterize the acoustic environment they inhabit. While increasing noise in the marine
environment and the potential to damage marine mammal hearing and/or interfere with
crucial vocal communications are valid reasons for concern, the information to scale those
concerns to actual effects is lacking. The NMFS’s task is to determine what levels
and types of underwater noise are harmful to marine mammals. The MMS must determine if
offshore industry noise and marine seismic operations represent a threat to marine mammals
and, if so, means to mitigate those effects. In June 1999, a workshop on protected species
environmental concerns for the Gulf of Mexico was sponsored by the MMS. The workshop
identified sperm whales as a key species to study for possible acoustic effects. Sperm
whales are an endangered species and appear to reside in areas of industry activity off
the Mississippi River delta.
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| Deepwater Program. Dr. Pat Roscigno, Chief, Environmental Studies Chief, briefed
the Committee on leasing in deep water. Deep water leasing has proceeded in an
unprecedented rate fueled by emerging technologies and the Deepwater Royalty Relief Act of
1995. The ESP is providing information for the safe and environmentally sound exploration
and production in deep water. This information is diverse in nature and ranges across a
broad spectrum of social sciences and environmental sciences. Immediate information needs
to focus on a model to estimate the transport and fate of deepwater subsea oil spills near
the seafloor. In order to better understand the benthic slope communities, a comprehensive
survey of the environment was initiated. Another study examines the effects of oil and gas
exploration and development at slope sites. Social science studies are underway to examine
the impact of deepwater development on industry labor needs, workforce availability, and
commenting patterns. Future emerging issues will require information on gas hydrates that
have the potential to be geohazards and are associated with chemosynthetic communities.
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| Physical Oceanography Slope and Rise of the Gulf of Mexico Workshop. Dr.
James Coleman, OCS Scientific Committee member, summarized the results of the workshop. He
stated that oil and gas exploration in the Gulf of Mexico at depths greater than 1,000
feet has increased considerably. An initial workshop held April 22-14, 1997, addressing
environmental factors of deep water exploration recommended a three-component physical
oceanography approach. The approach would increase the MMS’s understanding of
physical oceanographic processes. The first component would reanalyze existing
observations and suggest a field program design. The second component was to use numerical
models to enhance understanding of physical processes in the region. The final component
was to conduct a field program to gather measurements to characterize the processes and
provide information on environmental assessment and oil spill assessment tracking. Current
measurements made during these exploratory studies revealed surprisingly strong currents
in deep water. Because of these findings and recommendations of the SC, the MMS conducted
a workshop on September 12-14, 2000, on physical oceanography of the Gulf of Mexico. The
main objective of this workshop was to review the design submitted from the reanalysis
effort and suggest modifications to ensure its information yield and successful
deployment. |
For more information, contact Julie Reynolds.
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