Chapter 7 - WORKING GROUP REPORTS

Chairman: Mark Huntley

Rapporteur: Steve Nicol

Members: Charles Greene

Suzanne Razouls

Tsutomu Ikeda

Sigrid Schiel

Victor Marin

Jon Watkins

Langdon Quetin

Stanislaw Rakusa-Suszczewski

Robin Ross

** Salpa thompsoni

* Euphausia crystallorophias

* Calanoides acutus

* Calanus propinquus

Themisto gaudichaudi

Metridia gerlachei

Rhincalanus gigas

Thysanoessa macrura

Sagitta gazellae

TABLE 1

Reproduction       days - months       1 - 10 km (H)
                                       1000 m (100 m resolution)

Migration (H)      days - weeks        10 - 100 km

Migration (V)      hours - seasonal    300 m
Swarming           hours - weeks       10 m - 10 km

Mortality     
 a) "natural"      weeks               microscale - gyre scale
 b) predation      seconds - months

Growth             days - weeks

Life cycle         2 - 3 years         gyre scale
                   (hatch - Hatch)

*Note: Sample to 1000 m for copepods

The quasi-synoptic survey cruises should take place at approximately monthly intervals for a minimum period of three years, in order to resolve the full life cycle of E. superba and other key species. These cruises should encompass shelf, slope and oceanic environments (Fig. 1), with the aim of resolving mesoscale features in both the biotic and dynamic physical environments.

Process cruises should focus on the processes and mechanisms identified above, and should be directed on a phenomenological basis from information arising from results of the survey cruises.

Remote sensing aspects of the program should incorporate new and existing technologies capable of yielding synoptic data over long time scales.

In general, the working group recommends that this project could feasibly begin by 1996-97. It would involve multiple ships from different nations, and would require that a common quasi-synoptic survey grid be occupied at different times by all participants.

It was noted that sampling strategies may differ depending upon the species being investigated. For example, while the 200 m depth horizon may be adequate for a study of juvenile and adult krill, the 1000 m depth horizon may be more appropriate for copepods and early larval stages of krill.

7.2 Benthic Working Group Report

Chairman: Donal Manahan

Rapporteur: Jackie Grebmeier

Members: Wulf Arntz

Rennie Holt

Jim Barry

Ken Smith

Ulrich Bathmann

Bill Stockton

Paul Dayton

Martin White

1. Ross Sea/McMurdo Sound: high Antarctic (USA)
2. South Orkney/South Shetland Islands: low Antarctic (eg. UK, POL, D)
3. SE Weddell Sea: high Antarctic (D)
4. Davis Sea: high Antarctic (AUS)
5. Antarctic Peninsula: low Antarctic (various countries)

1. Measurable growth parameters
2. Abundant
3. Wide or restricted distribution (either group will react to climate change differently)
4. Known life history
5. Amenable for reproductive studies

1. Bivalves, e.g. Adamussium (p), Laternula (p), Mysella (b), Gamardia (b)
2. Echinoderms, e.g. Odontaster (p), Sterechinus (p), Ophionotus (p), Diplasteria (b)
3. Crustaceans, e.g. Notocrangon (p), Chorismus (p), Glyptonotus (p)

1. carbon flux
2. ice conditions
3. current flow
4. temperature and salinity
5. light regimes
6. redox profiles in sediments.

1. energy flow
2. physiology
3. population dynamics
4. community studies.

Chairman: Inigo Everson

Rapporteur: Valerie Loeb

Members: William Fraser

Adolf Kellermann

Tony Koslow

Richard Veit

The reproductive success of Southern Ocean birds and seals has been shown to depend on interannual variations in prey abundance (Croxall et al., 1988); their long term fluctuations in abundance have been related to changing sea ice conditions (Fraser et al., in press). Therefore these higher predators are especially valuable to a program designed to detect the biological effects of global warming.

There are other practical reasons for their inclusion. Birds and seals can be more easily and inexpensively surveyed than other pelagic animals. While foraging, they perform spatially and temporally integrated "sampling regime" over a substantial area. Lengthy time series already exist on the reproduction and abundance of several of the numerically dominant species (e.g. Adélie and chinstrap penguins, fur and crabeater seals) in various locales (Palmer Station, King George Island, Signy Island and South Georgia). Furthermore, the recently established CCAMLR Ecosystem Monitoring Program (CEMP) which involves studies on selected bird and seal species. The results of this program have direct relevance to GLOBEC. Studies focused on fishes and higher predators will provide information on the relationships between predator-prey and their environment which is critical to understanding variability in the Southern Ocean ecosystem. Such studies may also provide the bases for monitoring the effects of man-induced perturbations.

The group agreed that in order to detect changes in fish and higher predators induced by climatic change it is essential to establish long term base line monitoring. These studies are dependent on having good information from field studies and modeling exercises identifying critical processes.

7.3.2 Site selection

Commercially harvested species:

Champsocephalus gunnari

Notothenia larseni (by-catch)

Electrona carlsbergi

Non-harvested holopelagic species:

Pleuraggramma antarctica

Electrona antarctica

Non-harvested nearshore species:

Notothenia neglecta

Trematomus hansoni

Harpagifer sp.

The target penguin and seabird species are primarily krill predators considered important by CEMP: Adélie, chinstrap, macaroni and gentoo penguins; cape and Antarctic petrels; Black browed albatross. Because of their different feeding activities we also feel it would be useful to include the grey headed albatross (fish and squid prey) and South Polar skua (which feeds on Pleuragramma antarctica ) as target species. The mammalian target species are crabeater and Antarctic fur seals. Both are dependent on krill, but occupy different habitats analogous to those of Adélie and chinstrap penguins.

7.3.4 Definable populations

1. The effect of temperature on growth and development rates of different ontogenetic stages of fishes:
2. Overwintering studies of higher predators to gain knowledge of a critical mortality period;
3. The possible effects of increased UV radiation on near surface fish eggs and larvae. Indirect effects include:
4. Hydrographic conditions and dispersal of pelagic early life stages of fishes:
5. The importance of food (e.g. krill) availability on fish condition, reproductive behavior (e.g. gonadal development, timing of spawning);
6. Foraging. dynamics of higher predators in relation to prey abundance and aggregation behavior.

1. Physical oceanography (e.g. temperature, water column stability, dynamics) and resulting effects on food supply, growth and development rates, survivorship, and dispersal during early life stages of fish;
2. A standard population dynamics model for seabirds, integrating physiological data and environmental variables;
3. Movement and dispersal of foraging predators (based on behavioral data) relative to acoustically detected prey target distributions to determine how seabirds and seals locate food patches.
4. Fisheries vs. climate related effects on harvested species.
5. Trophodynamic models of multispecies interactions between fish and higher predators and their prey.

1. Improved acoustics hardware and software for the location, identification and quantification of fish;
2. Underwater visual systems for assessing prey (krill, pelagic fish) distribution;
3. Improved satellite tracking and time depth recording devices for predators;
4. Improved finer-scale resolution in remote sensing of sea ice coverage with differentiation of sea ice condition and other hydrographic conditions;
5. Improved finer-scale resolution of sea ice conditions through aircraft observations;
6. Biochemical methods for evaluating fish condition factors;
7. Genetic markers for determining stock identity;
8. Increased usage of Lagrangian drifters for assessment of current transport and advection.

Fraser, W. R., W. Z. Trivelpiece, D. G. Ainley and S. G. Trivelpiece. Increases in Antarctic penguin populations: Reduced competition with whales or a loss of sea ice due to environmental warming. Polar Biology, in press.

Laws, R.M. 1985. The ecology of the Southern Ocean. Am. Sci. 73, 26-40.

7.4 Physics/Climate Working Group Report

Chairman: Eileen Hofmann

Rapporteur: David Webb

Members: Joey Comiso

Jian-Hwa Hu

John Klinck

Peter Niiler

The accuracy of present climate predictions is limited by the relatively coarse (300 km grid) atmospheric and oceanic models used for climate research. However, the models indicate that in sea-ice regions the increase in summer temperatures will be substantially smaller than the global mean. Global warming will be delayed over the oceans with the greatest delay occurring in the Antarctic Ocean, just south of the belt of minimum westerlies.

The present models predict a reduced temperature contrast in the atmosphere between the equator and the poles. This will result in a reduced strength of the westerlies and a corresponding change in the strength of the Antarctic Circumpolar Current.

Finally, the models predict increases in the cloudiness of the atmosphere (resulting from increased evaporation). As the Southern Ocean is cloud covered, typically 80% of the time, even small increases in cloud cover could result in large changes in the biological productivity of the region.

7.4.3 Large-scale system

The polar gyres near the Antarctic Continent may be differrent from the large-scale structure. The location of the Weddell gyre is strongly influenced by the Antarctic Peninsula. The other, suspected, gyres (e.g. in the Ross Sea) may become much more evident if the Easterlies along the continent became stronger. These gyres might also extend farther into the Southern Ocean if the winds were to change.

Within the large scale, Antarctic Circumpolar Current, there are narrow (about 50 km in width) high speed current jets that are associated with density fronts. These jets are separated by relatively low speed zones of about 100km width. A study of surface drifters shows that these fronts are associated with a secondary circulation that leads to flow convergence at the surface (surface drifters tend to collect over the fronts). The strength and importance of this secondary circulation has not been investigated nor has its effect on biological processes.

The high speed, narrow currents in the ACC are subject to flow instability which leads to mesoscale eddies. This eddy variability is evident in satellite altimetric observations, specifically in the measures of the time variation of the height of the sea surface. In fact, the ACC stands out in the Southern Ocean as a band of large flow variation. There is also measureable flow variation near the Antarctic Continent but it is not clear how much of this is due to the presence of ice.

Within the band of high variability associated with the ACC, areas of even higher variations exist. The largest magnitude of the eddy kinetic energy occurs in the Agulhas Retroflection and near the collision of the Brazil Current and the Falkland Current. Lesser hot spots are over the Kerguelen Plateau, the Macquarie Ridge, the Campbell Plateau, the East Pacific Rise and the Scotia Arc. The implication of this observation is that mesoscale variability is driven to some extent by the interaction of flow in the Southern Ocean (which penetrates to the bottom with only slightly diminished speed) with relatively shallow (less than 1 km) parts of the Southern Ocean.

A comparison of phytoplankton maps from CZCS and bathymetry reveals a striking necessary condition: high phytoplankton occurs in regions of large bottom slope. However, not every region of strong bottom slope is associated with high phytoplankton concentrations. Some of the regions of high phytoplankton are also areas of high flow variability, but not all. The relationship among flow variability, bathymetry and high phytoplankton concentration is not clear at this time.

7.4.4 Sea-ice region

During winter, the presence of leads and polynyas are also significant factors affecting the environment. Their presence is known to cause a considerable change in heat fluxes between the ocean and the atmosphere and salinity fluxes between the ice and ocean. Leads are linear and random features of open water (or new ice) in the ice pack and are known to constitute less than 10% of the ice cover. Polynyas are more rounded features and have been classified as either sensible heat polynyas or latent heat polynyas. The sensible heat polynyas which are usually in the deep ocean and can cover large areas are believed to be caused primarily by upwelling over topographical features (e.g. the Maud Rise). Latent heat polynyas are usually located along the coast and are formed by katabatic (or synoptic) winds. Biological populations have been observed to be considerably enhanced in lead and polynya regions. A careful monitoring of these features is therefore important.

Consistent records of ice extent from satellite observations have indicated no significant change in ice cover during the past seventeen years. However, there have been large regional variations. Large polynyas in 1974 through 1976 were observed in the Weddell Sea, but not in other regions. In 1980, the ice cover in the Weddell Sea was 15% larger than normal. This was compensated by smaller than average sea ice extents in other regions such as the Ross Sea and the Indian Ocean during this period. Long term effects of global warming would reduce the seasonality of sea ice and perhaps result in the eventual absence of summer ice. However, on the short term, the effect is not too obvious because of the complex feed backs that exist between ice, ocean, and the atmosphere.

7.4.5 Coastal circulation

The historical hydrographic and current measurements that exist for the Antarctic are primarily concentrated in the Bransfield Strait-South Shetland Island region. These data reveal that the coastal flow in this region consists of complex circulation patterns that exhibit seasonal variability in strength and direction, in response to changes in wind stress and ice cover. The coastal currents are relatively narrow, being on the order of a few kilometers in width, but having large horizontal extent. For example the narrow westward flowing current on the north of the South Shetland Islands is thought to be circumpolar in nature. The coastal currents are influenced by bottom topography and coastal geometry, which can result in small scale variability.

Coastal regions such as the Bransfield Strait are areas where different water masses meet. This results in the formation of small scale frontal regions that can and do exhibit considerable variability in space and time. It is also likely that coastal flows are influenced by the amount of melt water from ice shelves and glaciers that is introduced each year.

Climate change effects could potentially affect the coastal circulation in the Antarctic through such processes as reduced inputs of melt water and/or changes in solar radiation. Either of these processes could alter water column stability, which would affect the intensity of veritcal mixing in coastal regions. Also, changes in the wind stress field would alter the intensity of the seasonal surface circulation.

7.4.6 Recommendations

Understanding the processes associated with sea-ice extent and variability are an important part of determining what (if any) effect climate change will have on the

Understanding of coastal circulation is a necessary component of addressing questions that relate to marine population fluctuations. Many species, such as krill, spawn on or near the continental shelf where their larval forms are dispersed by the coastal currents. Thus, understanding the factors that result in the successful recruitment of these species requires first a knowledge of the coastal current systems. The existence of shore-based laboratories makes coastal programs logistically feasible for the Antarctic.

There is a need for consistent and synoptic observations of sea ice and currents in the Antarctic. Attention should focus on designing measurement programs that use satellites, moored instrumentation and drifters.

7.5 Modeling Working Group Report

Chairman: Eileen Hofmann

Rapporteur: Victor Marin

Members: Joey Comiso

Jian-Hwa Hu

Tony Koslow

Dick Veit

David Webb

The present models do not realistically predict the ridging of sea ice or the formation of caverns by the rating of sea ice. Such models need development. The present models also do not attempt to describe the details of the flow field below the sea ice. However, this may be possible using a general circulation model with high resolution in the top 200 m.

7.5.2.5 Models for recruitment

1. Preliminary modeling efforts should be undertaken before field studies to ensure collection of optimal data sets. This part of the modeling would be based upon existing data and scientific intuition and where available incorporate historical time series data.
2. Models of biological processes should be based upon physiological principles and basic biology. This is a basic premise of the GLOBEC modeling philosophy.
3. The group strongly recommends the use of existing models especially mixed layer models, general circulation models, regional circulation models and sea ice models. The results of these models should be interfaced with biological models to investigate the role of physical and biological processes in determining biological distributions.
4. There is a critical need to invest resources in developing sea ice models to give a realization of the circulation associated with the sea ice field.
5. The group detected a need to transfer aggregation theories developed in terrestrial ecology to marine populations. This is of particular importance for models developed to study the swarming behavior of krill and models that treat the aggregation of predators in response to the swarms/patches of krill.
6. Physiological and basic principles models require measurements on rates and processes. This in turn requires close cooperation between models and experimentalists.
7. Biological models should explicitly incorporate large-scale variability in the physical environment.
8. A comprehensive model should be constructed in the end to integrate the aforementioned results.

Chairman: Sigrid Schiel

Rapporteur: Langdon Quetin

Members: Tsutomu Ikeda

Donal Manahan

Stanislaw Rakusa-Suszczewski

Robin Ross

Martin White

A. Considered GLOBEC Report Number 3 "Biotechnology Applications to Field Studies of Zooplankton" very important in regard to the need to investigate the following:

1. Metabolism and locomotory ability
2. Morbidity
3. Diapause
4. Egg production rates
5. Growth rates
6. Developmental stages
7. Age
8. Feeding rates and diet

B. Determinations need to reflect different time intervals in the physiology of the animal, i.e., long term versus short term changes in the state of the animal.

C. Need to consider all of the approaches in Report Number 3 and work toward

1. Reducing the number of measurements required
2. Simplifying measurement techniques

II. Seasonal studies need to be emphasized regarding

A. Environmental triggers of behavioral and metabolic events - in polar environments very small changes (i.e. 0.5 degrees C) may trigger change.

B. Comparisons of metabolic responses between extremes in the environment, e.g. summer versus winter. Most organisms investigated show seasonal cycles in metabolic activity.

C. May need new resources for station/ocean work throughout the year.

III. Physiological "plasticity" needs to be considered, especially to understand the capacity of antarctic animals to respond to environmental change (new to antarctic work)

A. Need detailed laboratory experiments to interpret simpler shipboard measurements in the context of an animal's metabolic history and consequences to its future.

B. Need to measure physiological responses by the target organism to conditions outside the normal environmental range normally encountered.

1. Consideration given to likely environmental changes based on model predictions for effects of global change
2. Identify possible changes in temperature, salinity, food, and ultraviolet radiation
3. Vary environmental parameters in small increments because of high Q10's found to date in invertebrates

1. Priority should be given to the early stages of development since their survival may be particularly sensitive to environmental conditions, concept of critical period during early life history

E. Important to explore the idea of the ability of Antarctic species to procrastinate a physiological decision, especially whether it is a generality for Antarctic species

IV. Additional specific questions

A. Krill and salps do not generally occur together. Is this separation in part due to physiological differences between the two species, or primarily due to physical conditions in the environment?

B. What physiological parameters should be measured during the life cycle or at specific stages of the target organism that would most likely be an index of processes affecting population dynamics?

V. Target species

A. Attention should be given to not only studying a few species in detail, but also to studying a greater number of species in less detail.

1. Detailed studies on a few species are important to evaluate which measurements are the most appropriate to emphasize.
2. Studies on a broad range of species should illustrate the generality of results from detailed measurements on a particular species, i.e., using the chosen parameters

1. Is a particular species suitable for experimentation?
2. Is it possible to obtain all life stages?
3. Is there historical data?

1. Plankton
   1. Euphausiids, recommend Euphausia superba
   2. Copepods, recommend Calanoides acutus
   3. Salpa thompsoni, because it generally appears to be found in the absence of krill
2. Benthos
   1. Echinoderms, Sterechinus sp.
   2. Crustaceans, Notocrangon antarcticus
3. Fish
   1. Pelagic
      1. Pleuragramma antarcticum (high latitude) or
      2. Nototheniops larseni (lower latitude)
   2. Demersal (near shore)
      1. Harpagifer or (larvae spend less time in water column, restricted distribution close to shore)
      2. Trematomus hansoni (near McMurdo Station, pelagic larvae, widely distributed over shelf)
4. Seabirds
   1. Adélie penguin.
   2. chinstrap penguin

The complexity of the benthos is greater than the planktonic community. For the benthos site selection should consider historical long term records, logistical constraints, and high and low latitude sites. The Ross Sea, McMurdo Sound and the South Orkney Islands should be considered possible sites. In the context of climate change the persistence of the benthic structure, the long term faunal and sediment record, and the ecological community structure should be considered. Some of the criteria for selection of target species shotrid be their abundance, whether they have a wide or restricted distribution, and whether measurable growth parameters exist.

The group discussed the merits of looking at a few species in detail or many species in less detail. The detailed approach was favored, but with a note that a broader range of species needs investigation at some level. For the detailed approach we need to consider how an organism responds to different carbon inputs, determine the physiological state of the organism and have the laboratory data to understand the implications. Ground truthing of physiological measurements and how different environmental variables affect the physiology of an organism is essential if we are to use these measures as assessments of the physiological state of an organism in the field (Fig. 1). Possible measurements included metabolic rate, growth, and (particularly for larvae) enzyme activity, amount of total protein and the pattern of synthesis of specific proteins. Concern was expressed about whether techniques were too sophisticated for field use and that they would not be something that "everyone" could do. Citrate synthase activity was suggested as an example of a useful and appropriate assay since the assay is simple, material needs to be frozen only at -80 degrees C, and citrase synthase is thought to be a good index of metabolism.

It may also be useful to better understand an organism's maximum potential versus what we actually see in the field. Growth rates would be a good example. Another question mentioned was how do we relate physiology to birth and death rates? or How do we relate physiological status to light, temperature, salinity and other abiotic factors? What followed was a general discussion of what to measure. Krill in Prydz Bay experience a constant low temperature compared to those west of the Antarctic Peninsula that encounter a 4-5—C range in temperature. The same species from different areas may show different physiological responses that may make "physiological state" difficult to interpret. It was mentioned again that growth was a good integrator of recent past environmental events. A combination of the biochemical and physiological approaches may be most suitable for GLOBEC. However, we need to be aware of potential problems. One example mentioned was the contribution of enzymatic activity from bacterial enzymes in krill stomachs to any analysis of krill.

Physiological rates should be evaluated in terms of their relevance to population dynamics. In addition, the relative importance of stages to measure since the work load may need to be prioritized. It was also emphasized that there should be a thorough review about what we know of particular species important to the study, and a critical evaluation of past research.

7.7 Population Dynamics Working Group Report

Chairman: Jarl-Ove Stromberg

Rapporteur: Adolf Kellermann

Members: Wulf Arntz

Tony Koslow

William Fraser

Suzanne Razouls

Jacqueline Grebmeier

William Stockton

Mark Huntley

The potential study areas were the Bellingshausen Sea and adjacent waters to the east, but it was felt that because of logistic constraints of national ongoing and planned projects, other areas such as the Weddell Sea or Prydz Bay should be taken into consideration. These may also be utilized to look at a given target species under different latitudinal regimes, or the shipborne work in the primary study areas may be complemented by shore-based studies in different regions on e.g. rates and processes. In general, the group acknowledged that the most striking andimportant gap is the lack of data from the winter months for all taxonomic and ecological groups.

7.7.1 Benthos

Chairman: Jon Watkins

Rapporteur: Ken Smith

Members: Ulrich Bathmann

John Klinck

Inigo Everson

Valerie Loeb

Charles Greene

Stanislaw Rakusa-Suszczewski

SENSOR        INSTRUMENTATION                    DEPLOYMENT PLATFORMS 

Mobile survey cruises

 Acoustics   Low-frequency acoustic array,       towed
             for school detection or tracking**

             Multi-frequency surface acoustics   towed body, hull mounted
             (existing), dual-, split-beam* (**)  

             Multi-frequency remote acoustics    multiple nets, towed bodies
             (prototype), dual-, split-beam**    and vechicles

             Acoustic Doppler Current Profiler   hull mounted
             (ADCP)*

 Optics      Optical particle counter**          nets and towed bodies
						            
             Video camera systems* (**)          towed bodies, vehicles and
                                                 benthic sledges

 Sampling    Automated sample processing         multiple and high-speed trawls
						             

Process oriented cruises

 Acoustics   Acoustic volume imaging systems**    ROV's, profilers,submersibles

             Side-scan sonar (others from above)*

 Optics      TV and still cameras, still* and     Profilers, ROV's, divers
 


Fixed location experiments

 Acoustics   Low-frequency acoustic array**
                        
	     Acoustic volume imaging**

             Acoustic transponder and receiving
             arrays for predator-prey studies**

 Optics      Micro video cameras for predator-
             prey studies (High definition)*(**)

Moorings
    
 Acoustics   Multi-frequency acoustics*(**)       vertical profiling arrays
	     ADCP's*(**)			     

 Optics      Longterm cameras* and videos         cameras such as Bathysnap
						             
 Sampling    Bottom landers for growth and
             physiology***

Everson, I. and D. G. Bone. 1986b. Effectiveness of the RMT-8 system for sampiing krill (Euphausia superba) swarms. Polar Biology 6: 83-90.

Foote, K. G., I. Everson, J. L. Watkins and D. G. Bone. 1990. Target strengths of Antarctic krill (Euphausia superba) 38 and 120 kHz. Journal of Acoustic Society of America 87: 16-24.

Marine Zooplankton Colloquium 1, 1989. Future marine zooplankton research - a perspective. Marine Ecology Progress Series 55: 197-206.

Murphy, E. J., D. J. Morris, J. L. Watkins and J. Priddle. 1988. Scales of interaction between Antarctic krill and the environment. In: D. Sahrhage (ed.), Antarctic Ocean and Resources Variability, pp. 120-130, Springer, Berlin.

Price, H. J. 1989. Swimming behavior of krill in response to algal patches: a mesocosm study. Limnology and Oceanography 34: 649-659.