Twenty scientists representing a wide range of expertise met from 30 September to 1 October 1998 at the National Science Foundation (NSF) in Arlington, VA, along with representatives from the Office of Polar Programs and the Division of Ocean Sciences (participant list, Appendix 1). The objectives of this workshop were to: 1) design the U.S. field program contribution to the Global Ocean Ecosystems Dynamics (GLOBEC) Southern Ocean program and 2) provide guidance to the NSF on how the U.S. may contribute to the GLOBEC Southern Ocean program. The workshop began with a brief discussion of the Southern Ocean GLOBEC (SO GLOBEC) science and implementation plans published in International GLOBEC Reports 5, 7, and 7A, respectively. This discussion emphasized the fact that while many of the original science issues had been revised, SO GLOBEC continued to stress the importance of international cooperation and understanding interactions between physical forcing and biological responses in the marine environment.
The next portion of the workshop agenda (Appendix 2) consisted of presentations intended to highlight issues of importance to SO GLOBEC. The first of these was an overview of developments in the SO GLOBEC program. This presentation stressed the importance of year-round studies and austral winter observations to SO GLOBEC objectives. It was also emphasized that krill (Euphausia superba) remain the research target species for SO GLOBEC and that there is a pressing need to understand krill ecology in the broader context of habitat preferences, feeding ecology, and interactions with its predators and competitors. Subsequent presentations dealt more specifically with aspects of krill ecology as they are currently understood.
The first overview reviewed recent studies documenting the importance of krill-sea ice interactions in structuring the Antarctic marine ecosystem (e.g., Siegel and Loeb, 1995, Marine Ecology Progress Series). This presentation emphasized the importance of winter sea ice as critical habitat to Antarctic krill and the significant role that salps may play as krill competitors during the non-winter months. The second presentation outlined the strong linkages that have been observed between the foraging ecology of Adélie penguins, krill recruitment success, and sea ice cycles in the western Antarctic Peninsula region. The extreme sensitivity of these krill predators to changes in krill availability was illustrated. Thus, the ecological dynamics of krill predators can be employed as proxy measures in field studies seeking understanding of how physical forcing cascades through the food web.
The third presentation reviewed present knowledge of the hydrography and circulation of the west Antarctic Peninsula continental shelf. The hypothesis was put forward that the mesoscale gyres now known to occur along this Peninsula shelf may serve as important krill retention areas in this region. In addition, the importance of the Circumpolar Deep Water in mediating regional-scale sea ice formation was proposed and supporting data presented. The last two presentations provided overviews of the NOAA Antarctic Marine Living Resources program and of potential interactions between SO GLOBEC and the International Whaling Commission (IWC).
Following these talks, workshop participants commented on the apparent cohesion between the data supporting the various presentations and agreed that SO GLOBEC has the potential to fill some missing key elements in our emerging understanding of ecosystem dynamics in the western Antarctic Peninsula region. The workshop participants then divided into two working groups, which focused on habitat variability and predator-prey interactions. The results of the deliberations of these working groups are given in sections 4 and 5.
The two primary results of the workshop were: 1) the U.S. SO GLOBEC program will focus on winter studies and 2) the study site will be moved to the region near Marguerite Bay (discussed in Section 3).
Southern Ocean GLOBEC will focus on Antarctic krill as the primary target species. This focus, however, includes the habitat, prey, predators, and competitors of this species. The SO GLOBEC program will be a year-round study, with emphasis on austral winter processes. Recent evidence indicates that seasonal coverage is necessary to fully understand the linkages between the environment, krill, and top predators. The science questions that underlie SO GLOBEC reflect these emphases.
The zooplankton science questions are:
The predator science questions are:
The primary field effort for SO GLOBEC is scheduled to begin in 2000/2001 and will focus on two primary sites: the western Antarctic Peninsula and Prydz Bay (E) regions. The western Antarctic Peninsula region will be studied through a multi-nation, multi-ship effort in order to obtain seasonal coverage, especially in the austral winter. Studies in the Prydz Bay region will be primarily seasonal.
The U.S. contribution to the SO GLOBEC program will be field studies in the western Antarctic Peninsula region. The International SO GLOBEC Planning Group recommended (International GLOBEC Report 7A) a region near Anvers Island as the field study site for the Antarctic Peninsula program because the site has both krill and krill-dependent predator populations, is subject to seasonal ice coverage, and may be a region of low advective flow.
At the U.S. SO GLOBEC workshop, it was decided to move the field study site further south along the western Antarctic Peninsula to a region in the vicinity of Marguerite Bay and to use the Anvers Island site as a source of retrospective, comparative data. Careful consideration of winter predator distributions and the hydrography and circulation of the Marguerite Bay region suggested that this area would better meet the science objectives of SO GLOBEC. For example, there is evidence that large numbers of krill-dependent predators (e.g., penguins, seals, and whales) winter in the Marguerite Bay area, which suggests the presence of a dependable food source such as krill. Also, there is evidence of a recirculating gyre in this region and evidence of Circumpolar Deep Water upwelling. The latter is warmer and its effects may produce dependable regions of open water in winter. Some workshop participants opposed this change and felt that this may compromise the international collaborations that are necessary to obtain the year-round coverage desired by SO GLOBEC. However, sampling nearer to Marguerite Bay will enhance cooperation with the British Antarctic Survey (BAS) and the BAS land-based station at Rothera. The issue of sampling in Marguerite Bay during winter was also raised. It was suggested that an analysis of ice conditions in this region, using satellite archives, be undertaken to establish the winter ice conditions.
This working group discussed approaches for measuring and characterizing the physical environment of the study site. They noted that understanding the shelf circulation, especially on- and off-shelf exchanges, was critical to the goals of SO GLOBEC. The working group recommended that the study site for the physical environment include the entire shelf and extend to the shelf break. It was thought that surveys using instruments, such as SeaSoar, would be time efficient and provide information on a broad range of scales. The working group placed a high priority on characterizing the habitat of the study area throughout the period of the field experiment through a series of high resolution mesoscale surveys.
Many regions of krill abundance seem to be characterized by mesoscale physical features such as gyres. It has been hypothesized that these features in some manner facilitate the retention of krill at various times of their life cycle in a defined geographic region. Indeed, the ability of krill to remain in a region of enhanced productivity is critical to their reproductive success. As such, it is essential to characterize the mesoscale physical environment in which krill grow and reproduce. Measurements will be needed to assess the residence times of the waters within these features and contrast that with measurements in surrounding waters. Furthermore, it is important in some manner to establish the residence time of the krill themselves and compare that with the residence time of the water per se. Such an assessment will allow the nature and degree of physical-biological coupling within the krill life cycle.
In addition, the group noted that the temporal scales of variability on the continental shelf create challenges to place a short-term study in larger, longer context. For example, the shelf is impacted by multi-year variations in ice distribution and concentration, which in turn are likely related to large-scale physical teleconnections to ENSO events. Variations in cross-shelf exchanges with Antarctic Circumpolar Water sources have different scales of variability but likely occur numerous times each year and are seasonally dependent on forcing. Finally, short-term variations induced by storms also contribute to environmentally important variations. We recommend that, to the degree possible, all times scales be adequately addressed using appropriate satellite and moored instrumentation (e.g., current meters, acoustic Doppler current profilers, and temperature sensors) in order to place the variations observed in a monthly or year-long study in a broader, more ecologically significant context.
A critical part of addressing the science objectives of SO GLOBEC is determining the distribution of krill under the sea ice in winter in a quantitative manner. The working group felt that this would be best done through the use of autonomous underwater vehicles (AUVs), remotely-operated vehicles (ROVs), and optical plankton recorders. Clearly any AUV or ROV must have acoustic sensors that have been agreed upon by the international acoustic community to provide a reliable and consistent estimate of krill biomass. Furthermore, SO GLOBEC should consider the need to assess winter food sources for krill, including ice algae and plankton. Ice algae are a concentrated source of organic matter and krill are known to utilize it during winters, but the quantitative contribution of ice algae to krill overwintering success is unknown. An assessment of ice algal distribution, composition, and variability (both spatial and temporal) would contribute greatly to SO GLOBEC objectives.
Ice clearly plays a major role in the ecology and reproductive success of krill, but little is known concerning the small-scale variations in the habitat created by small-scale ice properties that in turn cascade to create impacts on krill. For example, leads in ice have been hypothesized to create short-term (hours to days) enhancements in the underwater irradiance field and stimulate small-scale productivity events. These leads could have a direct (i.e., food source) or indirect (behavioral change) effect on krill as well. Given that such physical variations in ice occur throughout winter, their impact on krill wintering strategies needs to be assessed.
The need for hydroacoustic surveys to determine krill distributions below the sea in ice-covered regions was noted. Sampling through the sea ice with net surveys was agreed to be difficult but is needed to provide ground truth observations for the hydroacoustics, as well as providing specimens for ship-board laboratory studies. A clear examination of the relationship between krill in the water column and those associated with the ice is needed, using similar and quantitatively comparable sampling techniques.
The predator-prey working group agreed to first review the predator research questions given in International GLOBEC Report 7A and to discuss and recommend variables and measurements to be made during the field program based upon the review of these questions. Moreover, because the U.S. part of the program will operate during the winter months, the working group decided to review these questions within the context of winter research. Given this qualification, it was thus agreed that question 2 (see section 2.0) was outside the scope of the U.S. program but still essential for the overall international SO GLOBEC program. Question 3 (see section 2.0), which would require multi-year data to address, was also outside the scope of the SO GLOBEC effort because it encompasses only a single year of field activities. Nevertheless, this question was also considered essential to the International GLOBEC effort, and it was suggested that it be researched with retrospective data from the Anvers Island-Marguerite Bay regions. Consequently, it was not discussed further in the context of recommending components and measurements for the U.S. part of the (winter) field program.
The working group thus viewed Question 1 (see section 2.0) as being the most directly relevant to the U.S. GLOBEC Southern Ocean program but found it advisable to rephrase this question slightly to place krill in the same central role it plays within the scope of the International SO GLOBEC program. This was done based on the premise it would provide improved cohesion to the full program. The revised wording for question 1 is:
The working group agreed that this question could be answered by comparing the consumption and population characteristics (e.g., size-frequency distributions, sex ratios, etc.) of krill taken by predators with similar characteristics based on sampling in the water column and beneath the ice. The group also agreed that the work required to address the revised question 1 would involve much of the same activity as work to address the former question 1. However, to more explicitly accommodate aspects of predator distribution and foraging ecology, and their relation to characteristics of krill distribution, availability and demography, the following supplemental question was posed:
Before proceeding to address predator measurements, the working group discussed required krill investigations. Identified as critical were the related issues of obtaining quantitative measures of krill distribution and abundance and determining the importance of under-ice habitat for overwintering krill. At present, only anecdotal information is available to suggest ice may be an important part of krill habitat in winter, and this hypothesis must be investigated fully. Standard methods for assessing krill distribution and abundance in the water column (nets and hydroacoustics) have not been demonstrated to be effective in detecting and quantifying krill under the ice. The use of ROVs and/or AUVs were thus proposed as methods offering the best chances of success for obtaining quantitative measures of krill distribution and abundance in the ice and for assessing the relative importance of this habitat to krill ecology.
In terms of implementing the group's suggestion, a proposal was made to design a stratified sampling plan that would use the AUV/ROV in conjunction with standard techniques to assess the importance of ice as krill winter habitat and to quantify krill abundance and distribution. The group thought this was feasible and so essential to the program that field experiments should begin in advance of the SO GLOBEC program. In this regard, the U.S. Navy was reported to be currently using an AUV or ROV in the Arctic for under-ice surveys, thus demonstrating in a general sense the feasibility of conducting an Antarctic program with this equipment. This led to the further recommendation by the working group that the Office of Naval Research Arctic program manager be contacted to obtain further information on this and to assess the feasibility of using this equipment as part of SO GLOBEC. The working group also recommended that the research and development aspects of using AUVs and ROVs to map distributions under ice be worked out in advance of SO GLOBEC. It was proposed that one way to do this would be to specifically link one of the krill research questions in section 2.0 to these devices within the context of an experiment to be carried out during the summer prior to the winter US GLOBEC program.
5.3.1. Sampling. Four categories of krill-dependent predators were identified: Adélie penguins, pack-ice seals, pelagic fishes, and minke whales. For each predator category, it was suggested that measurements be complementary to the extent possible between taxa; that is, that the data collected convey comparable, scale-relevant ecological, and/or physiological information between species. To this end, the working group acknowledged that most of the contemplated survey and experimental methods have biases that may limit between-taxa comparisons. However, since most of these techniques are in use today and are in some cases associated with historical data, the group also felt that correction factors could be applied with enough confidence to provide indices that are comparable between taxa. Another issue addressed regarding the acquisition of comparable data was the question of sampling scale. Predator studies tend to be fundamentally small scale and process oriented, while prey and physical oceanographic studies tend to encompass large scale surveys. A possible solution discussed in regard to this issue was the use of two sampling platforms, although the actual availability of two ships is likely to remain open-ended until further logistical assessments are made. The group felt that this approach would allow for nesting of the small scale process studies within the large scale surveys. The acquisition of the measurements and data described in the following sections was thus recommended to address some of the issues and concerns.
5.3.2. Distribution and Abundance. These data were regarded as one of the most essential to the predator studies in that proven methodologies exist that are capable of establishing links and comparisons between taxa and between scales. Although data on absolute abundances were regarded as the most desirable, the group agreed that relative abundances may be equally effective in meeting the stated objectives. Also recommended as complementary data was the acquisition of coincident information on the physical environment, with satellite images and bathymetry of the study areas considered indispensable.
5.3.3. Foraging Ecology. The winter foraging ecology of all the major Antarctic predators remains virtually unknown and the working group acknowledged that SO GLOBEC may provide one of the best opportunities to fill this critical gap. In this regard, the analysis of stable isotope ratios was identified as one method for which data could likely be obtained for all the predators identified in Section 5.3, including minke whales which could be sampled by using crossbow-propelled instruments. Assessing and quantifying diets via stomach content analysis was also considered essential to the study even if whales could not be included in the samples. The remaining species could be sampled by using a variety of proven methods, including stomach lavage (penguins and seals, which are released unharmed after sampling) and net capture (fishes). Lethal take of seals was not considered an option and was discouraged by the working group. Due to the importance of knowing the spatial and temporal patterns of predator foraging, the working group also recommended that serious consideration be given to the deployment of various instruments, including satellite transmitters (PTTs) and/or time-depth recorders (TDRs) on penguins, seals, and, perhaps, whales. TDR data in particular could provide invaluable information on where predators are foraging relative to the under-ice/water column habitats. Such data would also complement the sampling efforts of investigators involved in assessing the distribution and winter ecology of krill.
5.3.4. Energetics and Physiology. The working group agreed that some comparable data on body condition for all predators that could be easily captured would be highly desirable. Given the research platforms likely to be available, however, it was noted that direct measurements of these parameters could only be obtained for the pelagic fishes, which could be housed in appropriate experimental chambers. Data for the other species would have to rely on indirect measurements, such as the analysis of blood, blubber, and other tissues. The working group nevertheless agreed that even indirect measurements of body condition would provide the comparable data needed to develop adequate energetics models due to the availability of other essential information, such as predator diets, body weight, sex, age, etc. that be obtained during the normal course of research.
5.3.5. Retrospective Studies. Acknowledging that data reservoirs and archives exist, including, possibly, samples and data that are not yet analyzed, the working group emphasized that retrospective studies be an integral part of SO GLOBEC. Such analyses could not only provide answers to some of the questions identified in Section 2.0 for which multi-year data are needed, but could also be used to optimize the overall experimental design associated with the single-year SO GLOBEC program by identifying the truly essential data that are needed to fill critical ecological gaps.
The announcement of opportunity for the U.S. Southern Ocean GLOBEC program will be drafted during Fall 1998. After approval by the appropriate groups in the NSF, it will released to the community in early 1999. Proposals submitted in response to this announcement of opportunity will be due at the NSF, Office of Polar Programs by 1 June 1999. Peer-review and NSF review of these proposals will take place during summer 1999 and awards will be made in Fall 1999 for a field program that will take place in austral winter (May-September) 2001. Proposals that focus on modeling and retrospective data analysis will also be solicited as part of the announcement of opportunity.
The U.S. Southern Ocean GLOBEC program is part of a larger international effort. Therefore, it is important that the U.S. program be coordinated with field activities in other nations, such as Germany and the United Kingdom. This will be done through regional planning meetings which will be scheduled for March to April 1999.
An important aspect of the success of SO GLOBEC is obtaining year-round coverage in a region. A tentative ship schedule (Appendix 3) has been developed that will provide the needed coverage.
Other activities related to SO GLOBEC are being undertaken as part of the Modeling and Data Management working groups that have been appointed by the Chair of the International GLOBEC program. These working groups include participants from the U.S. SO GLOBEC community.
The IWC has indicated that understanding climate change effects on cetaceans is an area of emphasis and has initiated linkages to programs such as SO GLOBEC as part of their effort to address the scientific issues in this area. The IWC is developing a Southern Ocean Whale Ecosystem Research (SOWER) program and desires that a component of this program to be a joint field effort with SO GLOBEC. The IWC thus plans to place observers on SO GLOBEC ships to conduct tagging studies of individual whales and mesoscale surveys around the SO GLOBEC study area. The intent of these studies will be to bridge the smaller scales over which cetaceans feed with the larger scales over which cetaceans are distributed and which are currently the subject of IWC research via the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Some IWC funding and ship resources have already been allocated for participation in SO GLOBEC. The use of these resources will be determined in a series of planning workshops scheduled over the next year.
SO GLOBEC will take place the year following the CCAMLR Area 48 Synoptic Survey, and it is anticipated that observations, especially of krill, from this survey will be available to help plan the SO GLOBEC western Antarctic Peninsula study. Also desirable is to have CCAMLR participation directly in SO GLOBEC. SO GLOBEC will require participation by many groups and nations in order to provide year-round coverage of the western Antarctic Peninsula region. The opportunity exists for CCAMLR to provide part of this coverage and such participation would be welcome from SO GLOBEC.
David Ainley
HT Harvey and Associates
P.O. Box 1180
Alviso, CA 95002
Tel 408 263 1814
Fax 408 263 3823
email: dainley@harveyecology.com
Bob Beardsley
Department of Physical Oceanography
Clark 343, MS 21
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
Tel 508 289 2536
Fax 508 457 2181
email: rbeardsley@whoi.edu
Dan Costa
Department of Biology
Earth Marine Science Bldg.
Room A316
University of California, Santa Cruz
Santa Cruz, CA 95064
Tel 831 459 2786
Fax 831 459 4882
email: costa@biology.ucsc.edu
Mike Dagg
LUMCON
8124 Hwy 56
Chauvin, LA 70344
Tel 504 851 2800
Fax 504 851 2874
email: mdagg@lumcon.edu
Cabell Davis
Department of Biology
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
Tel 508 457 2000 x2333
Fax 508 457-2169
email: cdavis@whoi.edu
Mike Fogarty
Chesapeake Biological Lab
P.O. Box 38
Solomons, MD 20688
Tel: 410 326 7289
Fax 410 326 7318
email: fogarty@cbl.umces.edu
Bill Fraser
Polar Oceans Research Group
Department of Biology
Montana State University
Bozeman, MT 59717
Tel 406 282 7112
Fax 406 994 3190
email: wrf@gemini.oscs.montana.edu
Glen Gawarkiewicz
Clark Laboratory
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
Tel 508 548 1400
Fax 508 457 2194
email: glen@paddle.whoi.edu
Arnold Gordon
Lamont-Doherty Earth Observatory
P.O. Box 1000
Palisades, NY 10964
Tel 914 365 8325
Fax 914 365 0718
email: agordon@ldeo.columbia.edu
Eileen Hofmann
Center for Coastal Physical Oceanography
Crittenton Hall
Old Dominion University
Norfolk, VA 23529
Tel 757 683 5334
Fax 757 683 5550
email: hofmann@ccpo.odu.edu
Rennie Holt
US AMLR Program
Southwest Fisheries Science Center
P.O. Box 271
La Jolla, CA 92038
Tel 619 546 5601
Fax 619 546 7003
email: Rennie.Holt@noaa.gov
Mark Huntley
University of Hawaii
email: mhuntley@soest.hawaii.edu
Suam Kim
Korea Ocean Research and Development Institute
Ansan, P.O. Box 29
Seoul, 425-600
KOREA
Tel 82 345 400 6420
Fax 82 345 408 5825
email: suamkim@sari.kordi.re.kr
John Klinck
Center for Coastal Physical Oceanography
Crittenton Hall
Old Dominion University
Norfolk, VA 23529
Tel 757 683 6005
Fax 757 683 5550
email: klinck@ccpo.odu.edu
Bernie Lettau
Office of Polar Programs
National Science Foundation
4201 Wilson Boulevard, Room 755S
Arlington, VA 22230
Tel 703 306 1045 x7352
Fax 703 306 0109
email: blettau@nsf.gov
Valerie Loeb
Moss Landing Marine Lab
P.O. Box 450
Moss Landing, CA 95039
Tel 408 633 3304
Fax 408 753 2826
email: loeb@mlml.calstate.edu
Roberta Marinelli
Office of Polar Programs
National Science Foundation
4201 Wilson Boulevard, Room 755S
Arlington, VA 22230
Tel 703 306 1045 x7349
Fax 703 306 0109
email: rmarinel@nsf.gov
Mark Ohman
Scripps Institution of Oceanography
Marine Life Research Group
University of California, San Diego
9500 Gilman Drive
La Jolla, CA 92093-0227
Tel 619 534 2754
Fax 619 534 6500
email: mohman@ucsd.edu
Polly Penhale
Office of Polar Programs
National Science Foundation
4201 Wilson Boulevard, Room 755
Arlington, VA 22230
Tel 703 306 1033
Fax 703 306 0139
email: ppenhale@nsf.gov
Barbara Prezelin
Department of Biological Sciences
University of California, Santa Barbara
Santa Barbara, CA 93106
Tel 805 893 2879
Fax 805 893 4724
email: barbara@icess.ucsb.edu
Steve Reilly
Southwest Fisheries Science Center
8604 La Jolla Shores Drive
La Jolla, CA 92038-0271
Tel 619 546 7164
Fax 619 546 5657
email: sreilly@ucsd.edu
Walker Smith
Virginia Institute of Marine Science
Greate Road, Box 1346
Gloucester Point, VA 23062
Tel 804 684 7709
Fax 804 684 7293
email: wos@vims.edu
Phil Taylor
Ocean Sciences Division
National Science Foundation
4201 Wilson Boulevard, Room 725
Arlington, VA 22230
Tel 703 306 1587
Fax 703 306 0390
email: prtaylor@nsf.gov
Jose Torres
Department of Marine Science
University of South Florida
140 Seventh Avenue, South
St. Petersburg, FL 33701
Tel 727 553 1169
Fax 727 553 3966
email: jtorres@marine.usf.edu
Wednesday
30 September
0800 Continental Breakfast
0830 Welcome and Logistics Hofmann
0845 Overview of Southern Ocean GLOBEC Hofmann
0915 Krill-Ice-Ecosystem Interactions Loeb
0945 Penguin-Ecosystem Interaction Fraser
1015 Break
1045 Circulation and Hydrography of West Klinck
Antarctic Peninsula Continental Shelf
1115 NOAA/AMLR Program Holt
1145 Discussion
1215 Lunch
1315 IWC-GLOBEC Interactions Reilly
1345 Comments from Polar Programs Lettau/Penhale
1415 Discussion
1500 Break
1530 Convene Working Groups
1700 Adjourn for the day
Thursday
1 October
0800 Continental Breakfast
0830 Plenary Session
0845 Convene Working Groups
1015 Break
1130 Plenary Session
Reports from Working Groups
1215 Lunch
1315 Convene Working Groups
1500 Break
1530 Plenary Session
Reports from Working Groups
1700 Adjourn Workshop
2000 December AWI
2001 January AWI
February CCAMLR -- coordinated by S. Kim
March CCAMLR
April US --
May US | about 6 weeks within this 3 month period
June US --
July US --
August US | about 6-8 weeks within this 3 month period
September US --
October BAS
November BAS
December To be determined
2002 January To be determined
<\PRE>