PNNL-14540 Review of Deep-Sea Ecology and Monitoring as They Relate to Deep-Sea Oil and Gas Operations R.K. Kropp Battelle Marine Sciences Laboratory Sequim, Washington January 2004 Prepared for the U.S. Department of Energy under Contract DE-AC06-76RL01830 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor Battelle Memorial Institute, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 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Box 62, Oak Ridge, TN 37831-0062; ph: (865) 576-8401 fax: (865) 576-5728 email: [email protected] Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax: (703) 605-6900 email: [email protected] online ordering: http://www.ntis.gov/ordering.htm This document was printed on recycled paper. PNNL-14540 Review of Deep-Sea Ecology and Monitoring as They Relate to Deep-Sea Oil and Gas Operations R.K. Kropp Battelle Marine Sciences Laboratory Sequim, Washington January 2004 Prepared for the U.S. Department of Energy under Contract DE-AC06-76RL01830 Pacific Northwest National Laboratory Richland, Washington 99352 Executive Summary This review summarizes available information concerning deep-sea benthic ecology and how that information might be used to monitor and eventually reduce the potential impacts resulting from oil and gas production activities. The paper provides a brief overview of deep-sea ecology and benthic faunal groups and summarizes some of the physical and biological features that may be important in evaluating potential impacts. In addition, presented is a synopsis of issues related to the design of a sampling program and a discussion of analytical considerations related to the uncertain knowledge of deep faunas. Also included is an overview of some of the variety of sampling techniques and equipment available to study the deep sea. The review concludes with management considerations and recommendations. The deep sea is a dynamic biological environment, where rare species are known to exist under extraordinary conditions of tremendous pressures, low oxygen, cold temperatures, total darkness, and periodic storms. The review describes some of the adaptations necessary to exist under these extreme conditions. Impacts associated with exploration activities generally result from physical and biological disturbances. Impacts can also result from new habitat creation (e.g., the placement of a platform creates new habitat that can be colonized by a variety of organisms). Habitat assessments generally include acquiring information on the physical and chemical properties of the sedimentary environment, including grain size, availability of organic matter, and oxygen levels. Pros and cons are outlined of various methods of monitoring the density, diversity, and rarity of different benthic faunal groups, as are means of minimizing impacts to and preserving these species. Most studies of ecological communities in the sea have focused on defining community structure; however, the study of ecosystem functions, and especially the effects of anthropogenic activities on these functions, is also an important part of a benthic study. Structure is usually determined by obtaining a sample of the community and determining its constituent taxa. Measurements of function may include estimates of growth, reproduction, and development, or community processes, such as respiration and nutrient flux. Various considerations relevant to the design of a monitoring program are summarized, including aspects of sample collection, visual observations, manipulative experiments, and issues of spatial and temporal scales, particularly as they relate to statistical planning and analysis. Emphasized is the importance of clearly establishing goals in the planning stages, as well as practical considerations, such as maintaining the quality and comparability of data. Species-level analyses contain useful data about life-history patterns, reproductive strategies, and dispersal capabilities that can be used to anticipate impacts to communities, but more importantly, to gain insights into the potential for recovery from disturbance. Although achieving high quality and consistent taxonomic data can be difficult, it is cautioned that restricting taxonomic identifications above a species level cannot provide the same knowledge about community structural and functional changes in response to disturbance. iii Other means of assessing impacts to deep-sea organisms are also addressed. For example, although the study of biomarkers in deep-sea animals is in its infancy, it certainly holds promise for use in detecting exposures to foreign compounds. Field sampling equipment used on studies of the sea floor involve either tethered collection devices or non ship-linked techniques, such as submersibles. Examples of both of these primary types of data collection techniques are discussed, including sample collection and preservation techniques, sediment profile imagery, acoustic monitoring, remotely operated and autonomous underwater vehicles, and various sensor systems. Also considered are factors that affect the management of ecosystem monitoring programs, one of the most important of which is change. Understanding the effects of change is inherently complex, because change can be gradual or abrupt (e.g., in response to a catastrophic event), and the adaptability of ecosystems under widely fluctuating conditions can vary considerably. Given the dynamic, unpredictable nature of ecosystems, the integration of human activities and ecosystem conservation is difficult. Because there is often considerable uncertainty about how and when a system will change, an adaptive management approach is recommended to provide the flexibility required to manage effectively deep-sea resources. Recommendations to support a more effective monitoring program are outlined in the final chapter. Included are the importance of clearly stating objectives, designing a statistically relevant sampling and analysis plan that provides answers to the questions being asked, elements of structure and function, considerations of taxonomic identification of organisms, the potential use of alternative technologies, and the importance of disseminating the results to the broader community. iv Contents Executive Summary.....................................................................................................................................iii 1.0 Introduction.........................................................................................................................................1 2.0 Potential Impacts.................................................................................................................................3 2.1 Physical Disturbances................................................................................................................3 2.2 Biological Disturbances ............................................................................................................3 2.3 New Habitat Creation................................................................................................................4 3.0 Deep Sea Overview.............................................................................................................................5 3.1 Physical Environment................................................................................................................5 3.1.1 Pressure, Temperature, and Light.................................................................................5 3.1.2 Oxygen Minimum Zone ...............................................................................................6 3.1.3 Benthic Boundary Layer ..............................................................................................6 3.1.4 Benthic Storms .............................................................................................................7 3.2 Biological Environment ............................................................................................................7 3.2.1 Benthic Faunal Groups.................................................................................................7 3.2.2 Diversity and Rarity .....................................................................................................8 4.0 Habitat Assessment .............................................................................................................................9