James W. Murray University of Washington, USA, co-chair

Umit Unluata IOC/UNESCO, France, co-chair

Ozden Basturk METU/IMS/Erdemli, Turkey

Amy E. Callahan University of Washington, USA

Hugh W. Ducklow The College of William and Mary, USA

Leonid I. Ivanov Marine Hydrophysical Institute, Ukraine

Sergey K. Konovalov Marine Hydrophysical Institute, Ukraine

George W. Luther, III University of Delaware, USA

Alexandre S. Mikaelyan P.P. Shirshov Institute of Oceanology, Russia

James J. McCarthy Harvard University, USA

John Nevins Harvard University, USA

Temel Oguz METU/IMS/Erdemli, Turkey

Emin Ozsoy METU/IMS/Erdemli, Turkey

Emil Stanev University of Sofia, Bulgaria

Bradley M. Tebo Scripps Institute of Oceanography, USA

Alan Weinstein Office of Naval Research-

Evgeniy V. Yakushev P.P. Shirshov Institute of Oceanology,

Aysen Yilmaz METU/IMS/Erdemli, Turkey

Future research in the Black Sea should address the following topics.

1. The distributions of N₂, N₂O. PON, DON and d¹⁵N in the suboxic zone need to be determined to complete the description of nitrogen cycling.
2. There is no winter data. A good seasonal time series of concentrations and rates is required to constrain competing hypotheses regarding the formation of the suboxic zone.
3. Several specific reactions have been proposed involving N, Mn, Fe and S species. We know little about the stoichiometries and kinetics of these reactions and the role of biological catalysis. These need to be determined before accurate transport-reaction models can be constructed.
4. Vertical mixing is a key parameter for understanding distributions. Recent data suggest that conventional equations for predicting the rate of vertical mixing from water column stability (e.g. Gargett, 1984) are not appropriate in the Black Sea.
5. In the open ocean, the background mixing state is controlled by internal waves. The Black Sea is unusual because tides are very weak and wind is the main energy source. The natural period is only 5 hours, which is less than the frequency of daily or twice daily tides. We predict that intensities of internal waves will be less than in the open ocean and more variable.
6. 2-D and 3-D transport-reaction models need to be developed to simulate important horizontal processes from the shelf edge and the Bosporus inflow plume. New CFC data would be useful for calibrating these models.

1. Data for the annual biological cycle are missing. These data are is needed to describe and model biological processes in the upper layers of the Black Sea.
2. It is difficult to document environmental change in the Black Sea. Participating laboratories of contiguous countries need to establish annual time series with at least one coastal and one gyre station. Sampling should be done at least once per month.
3. We need a detailed study of the winter/spring bloom to evaluate existing competing hypotheses.
4. We need simultaneous measurements of primary production and POC, PON, DOC and DON export.
5. Factors determining the mortality of Mnemiopsis need to be determined.
6. A Black Sea GOOS program should be established as soon as possible.

This Workshop was held to provide timely input for observational plans proposed for NATO CCMS follow-on projects in the Black Sea and other new projects proposed to US-NSF and other agencies. The workshop included both US and European scientists so they could compare programs, recent progress and develop specific plans for future collaborations. In addition, we hoped to provide input to EuroGOOS, which is in an evolutionary stage.

Substantial progress has recently made in collecting new data and developing models. Coupled physical-food web models have been developed. One objective of this workshop was for modelers to discuss their problems with observationalists and visa versa. As new field work is planned, it is imperative to utilize the latest modeling results to improve the strategy and design of the field program.

The format of this workshop was to have short talks from both the data and modeling perspective and then synthesis discussion of future needs. Two areas were covered: the suboxic zone and the euphotic zone.

The 1988 R/V Knorr Expedition was a benchmark in terms of Black Sea Research. Several important programs were conducted in the following years.

CoMSBlack was the first International project on a basin scale. It was organized by David Aubrey (WHOI) and conducted field programs from 1991-94. This IOC sponsored project focussed mostly on physical oceanography, but did have some chemical and biological components. There were five multi-ship cruises to determine basin scale distributions and to study shelf and coastal processes. While CoMSBlack has not formally ended it is presently inactive.

The NATO TU-Black Sea project was conducted from 1993-97 as part of NATO’s Science for Stability (SfS) Program. The purpose of this project was to contribute to the improvement of the health of the Black Sea through utilization of ecosystem models as a management tool, through capacity building, and by fostering an interactive scientific community for the Black Sea.

This multi-institutional activity of five years duration was coordinated by the Institute of Marine Sciences, Middle East Technical University, in Erdemli, Turkey. It terminated in January 1998. Nearly 100 scientists from a total of 14 prominent oceanographic institutions (9 regional, 5 outside the region) collaborated to accomplish the three major objectives of the Project.

1. The first objective of the Project was development of a Data Base and Management System (DBMS) that includes environmental and oceanographic data pertinent to the goals of the Project and that serves as a base line for future research activities and management purposes.

2. The second objective was to assist in the development of appropriate infrastructure and capabilities within the Black Sea countries to carry out related future research and monitoring activities.

3. The third objective encompassed development and application of interdisciplinary ecosystem models of the dynamics of lower trophic levels of the biological community as affected by physical processes, changes in anthropogenic forcing and natural variability.

As a result of this NATO TU Project we have:

1. A unique Black Sea Data Base and Management System (DBMS)

In reference to interdisciplinary data, the DBMS developed through the TU-BLACK SEA Project is a first in Ocean Science. A Data Base Inventory (CDBI) was completed and distributed in hard copy and diskette forms to the Cooperation Partner Institutes and the relevant International Organizations. Data sets delivered by the participants were quality checked and transformed to standardized formats. The last thirty years of data from all the main regional and international sources has been included.

Final version of the data base (ASCII version) includes 12,790 files (149.4 MB). Data for 116 variables from 271 data sets, including 8,364,731 data values for 26,035 stations and is loaded into a CD-ROM. The total volume of data and information contained in the CD-ROM is 302 Mbytes. A demonstration version of the DBMS has also been created. DBMS will serve as a continuously updated base line for future activities concerned with the sustainable use and protection of the Black Sea environment. The address is: http://bsein.mhi.inf.net.

This unique data base management system will form a major foundation for future activities.

2. A well developed infrastructure for conducting research

Equipment for high quality, unified data collection and analysis has been provided to the Cooperation Partners Institutions. A satellite image receiving and processing system for common use has been put into operation. A communication network via Internet has also been developed. Substantial number of intercalibration /intercomparison exercises, modeling workshops/courses for cross training in methodology and in high quality measurements have been convened. Manuals / reports for chemical methods, criteria for unified biological sampling are made available to all the participants. Joint intensive/extensive observations through multi-ship surveys have been carried out and the data collected have been intercompared and pooled through collaborative analysis.

The analysis and/or synthesis of past and recent data through collaborative efforts have already led to a substantial number of joint publications in international journals. This activity has been instrumental in strengthening the foundations for cooperative scientific research in the region and in the rapid development of the DBMS by allowing rapid transfer of voluminous data to the system.

3. A series of interdisciplinary models has been developed.

The modeling activities took place in this project constituted research at the frontiers of ocean science. The models adopted were interdisciplinary, eddy resolving, primitive equation models that are based on up to date concepts and methodology. They were developed and applied for the Black Sea through collaborative research among the NATO and the Cooperation Partner countries.

Various biological and chemical interactions and cycles, including the microbial loop and those biochemical processes taking place within the suboxic zone, were modeled. The effects of the predator mnemiopsis leidyi on the dynamics of the lower trophic levels have been modeled successfully. The model predictions are consistent with the observations.

The major scientific publications based on the NATO TU Project include 27 refereed journal papers and 83 peer reviewed papers in books.

The TU-BLACK SEA Project cooperated interactively with the various programs concerned with the Black Sea environment. Linkages were established with The Black Sea Environmental Program of the Global Environmental Facility (UNEP, UNDP, WB), Global Ocean Ecosystem Dynamics Program, EROS 2000 (EU), The CoMSBlack program and the Black Sea Regional Committee of the Intergovernmental Oceanographic Commission (UNESCO), and the National Science Foundation (USA).

Recent efforts have led to development of new science plans. They are based on the anticipation that, with research and development plans based on sound scientific principles involving activities that constitute the regional efforts related to the global programs (such as GOOS and GLOBEC), international agencies and, more importantly, the governments of the Region can be convinced to financially support co-ordinated efforts towards systematic development of an ocean observation and forecasting system for the Black Sea.

1.1. A science plan related to creation of an ocean observing and forecasting system for the ecosystem of the Black Sea has been developed. The Science Plan defines the scientific and technological research issues to be considered as well as the strategies to be adopted for developing a Black Sea Observation and Forecasting System (BSOFS) in regards to the ecosystem of the entire Basin and its coastal and shelf seas over a ten year period. This plan was developed with the financial support from the NATO Committee on Challenges of the Modern Society (CCMS). It is intimately related to the Pilot Project 1 of the IOC Regional Committee initiated for the eventual launching of the Black Sea GOOS. Prominent scientists from the six Black Sea countries as well as scientists from the west participated in the generation of the plan which has been widely distributed starting at the end of November, 1997. A short description of BSOFS is given in Appendix III.

1.2. A science plan for creation and implementation of Marine Meteorological and Oceanographic Services for the Black Sea called "The BLACKMARS" has been drafted. The primary goal of BLACKMARS is to create a regional operational marine services system in the region and an operational information system.

A proposal has been submitted to NATO by the Bulgarian National Institute of Meteorology and Hydrology and METEO -FRANCE in regards to the development of the BLACKMARS.

A four year project under NATO Science for Peace Program (SfP) commenced in the Fall of 1998. The Project is entitled " The Black Sea Ecosystem Processes, Prediction and Operational Data Management" and will be carried out jointly by scientists from the Black Sea and NATO countries as well as the end-users. The project is essentially based on the BSOFS and is in effect a continuation of a recently completed NATO TU-Black Sea project.

Concurrent and highly coupled research and development activities will be carried out to explore, quantify, and predict the ecosystem variability of the Black Sea from the overall basin scale to the coastal/shelf areas, over time scales extending from days to months.

It involves the following:

A. Intensive field observations on specific processes (process studies) will be carried out for testing of the various crucial hypotheses. General analysis schemes will be developed for the identification and interpretation of coupled physical-biogeochemical ecosystem dynamical processes. The specific tasks of these activities will be to document, pathways, regulation of rates and feedbacks, population dynamics, and roles of physical, climatic and anthropogenic forcing in driving ecosystem variability of the Black Sea. Furthermore, these efforts will be critical for determination of various rate parameters including respiration, grazing, and particulate carbon export production that are needed in the models.

B. Coupled physical-biological-chemical ecosystem dynamical models with interdisciplinary data assimilation schemes will be developed, validated and applied. The models will involve:

• A basinwide ocean general circulation model (OGCM) for the physical component of the ecosystem, capable of simulating and predicting the three-dimensional structure of the flow field, temperature, and salinity distributions and of their time evolutions with mesoscale resolution, with particular emphasis on the coastal-shelf regions; and
• A biogeochemical model coupled to the physical model for simulating and predicting the seasonal and longer time variability and spatial distribution of contaminants, nutrients, and other living and non-living components of the ecosystem.

Other environmental issues that the coupled biogeochemical-physical model will address include exchanges of nutrients and other biogenic materials between the shelf and the interior, pathways of nutrient transport, translocation and change in the spawning / overwintering characteristics of fish, egg and larvae stocks and their correlation with the primary productivity on the regional scale.

C. A data base management system based on the existing NATO Black Sea Data Base and Management System will be developed. This is needed to develop innovative, efficient and practical ways of processing, archiving, and disseminating the large volume of data needed by the modelers. A fundamental issue here is the provision of services with fast turnover time without adversely affecting the accuracy of the resulting product, using sophisticated signal processing algorithms. When complemented with historical data, the existing data base and management system will also serve to monitor the environmental trends which are crucial from management perspective.

IOC established a Regional Committee (RC) for the Black Sea in 1995. The RC is charged with promotion, development and co-ordination of the regional marine science and services programs. In its first meeting in 1996, the RC launched two pilot projects, one involving preliminary efforts needed in initiating a regional GOOS program and the other involving biogeochemical fluxes in the Basin. The BSOFS and the BLACKMARS Science Plans mentioned above are the direct products of the former activity.

IOC is presently attempting to develop further pilot studies related to the Health of the Oceans and the Coastal Modules of the GOOS Program. These activities are envisioned to be the proof of concept exercises for the BlackSeaGOOS regional program planned to be launched in 1999.

With regards to the Intergovernmental aspects of the Black Sea marine environmental projects and programs, the following commitments of the Black Sea States are worth noting. By signing the Black Sea Strategic Action Plan on 31 October 1996, the six coastal states of the Basin have committed themselves, with the help of the international community, to an applied program of actions based upon common objectives and milestones for restoring the Black Sea from its present state environmental degradation. All the six states have authorized the Intergovernmental Oceanographic Commission to facilitate the development of regional capabilities in ocean observations, forecasting and data management. The riparian states are parties to United Nations Conference on Environment and Development and the Convention on Biodiversity, which stress the importance of having a scientific basis for decision making and establishing observation and data base management systems for the oceans. Governments of Turkey, Ukraine and Russia are among the coastal states who have adopted recent scientific programs whose primary goal is the creation of forecasting systems. Finally, the riparian states have given their approval to the BSOFS Science Plan under their joint agreements with NATO.

4. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA) BLACK SEA PROJECT

IAEA will carry out during 1999-2000 the third phase of its program called "the Marine Environmental Assessment of the Black Sea" which was initiated in 1995. The expected results of the Program are increased capabilities to evaluate the radioactive contamination of the Basin and the application of nuclear techniques in the assessment of marine pollutants. The activities planned for the third phase of the project include assistance for specialized training and equipment, expert technical support regarding routine monitoring, application of nuclear techniques, harmonization in methodology, intercomparison exercises, development of a data base, dispersion models of nuclear substances and a cruise in the eastern Black Sea. The activities will be co-ordinated with IOC and the Black Sea environmental Program.

Alan Weinstein pointed out that there are many seas with different degrees of connection to the ocean. All have interesting problems, but ONR can’t fund them all. Its approach will continue to be to pick one or two and do the job right. At present ONR is focussing on the Sea of Japan.

When planning future work consider the following. What do we already know? What are the key unanswered science questions? Who else is funding work in the region that can be used for leverage? Science for science sake is long past. The key is translating results to someone who can use them – the US Navy in this case.

• Need quality science with indication of how it can (will) be used.
• Need interdisciplinary system studies with strong basic science studies
• The Ecology of a Sea is one potentially important goal. Even more important for ONR is an acoustic understanding of a sea. Optical ramifications are also important.
• Look for processes that can be generalized to other seas.
• GOOS is developing worldwide but process studies are also needed for understanding.
• The Navy has major forecasting needs, especially close to shore.

What can IOC’s role be? They can assist with meetings for Program Planning Development. They can facilitate coordination on a larger basis.

GOOS has several modules and three are most important here. These are Health of the Ocean, Coastal and Living Resources. Each may want to start its own pilot study. One result of our workshop might be to propose a Black Sea GOOS as a pilot study.

A. Konovalov synthesized hydrographic and nutrient data from 52 cruises conducted since about 1960 (50 by MHI and 2 by US). His goal was to determine if there have been changes, and if so, can they be linked to anthropogenic effects.

Large changes were observed for O₂, H₂S, NO₃, NH₄, Si and P versus density. The time series suggests that, since 1960, the density value of the 20 mM O₂ contour has shoaled while the density of first appearance of H₂S has stayed constant. On a given density surface O₂ increased slightly from 1960 to 1970 then decreased from 1970 to 1990. Values have increased since 1990. On a plot of O₂ versus Θ, there appear to two modes, both with decreasing O₂ as a function of Θ. Samples before the middle 1970s have higher O₂ than those after the middle 1980s. Nitrate also has systematic changes and as O₂ has gone down, NO₃ has gone up. The changes occurred exactly with the Redfield ratio. So variation in the thickness of the suboxic zone appears due to respiration (Org C + O₂) rather than changes in the oxidation rate of H₂S.

Finally, Konovalov showed data suggesting that H₂S has increased in the deep water (at 1000m and 2000m) since 1985. This increase may correspond to increased export carbon flux due to eutrophication of the Black Sea because of nutrient input from rivers.

B. Luther began by giving an overview of the predicted sequence of redox reactions and a description of suboxic zones in the Black Sea, Chesapeake Bay and hemipelagic marine sediments. He then described new data sets from sediments off Nova Scotia and Quebec and in Raritan Bay, Long Island obtained using a potential scan with a single Au/Hg electrode. Data were obtained simultaneously for O₂, H₂O₂, HS^-, I^-, Fe²⁺ and Mn²⁺. Using this data he evaluated the thermodynamic feasibility of possible redox reactions involving N, Mn, Fe and I species. Most of this has been published but there was good discussion about coupled Mn-N reactions and the total N sink in the suboxic zone. Manganese cycling plays an important role in both oxidation and reduction reactions of S and N.

C. Tebo had no new data from the Black Sea but he summarized his 1988 evidence that both Mn oxidation and reduction were occurring in the suboxic zone.

He hypothesized that there is a redox pump due to horizontal transport of MnO₂ made in the coastal zone into the interior where it reacts with HS^- . This results in a vertical separation of O₂ and NO₃^- from HS^-.

He then summarized 7 areas of recent progress in related topics. These were:

1. Aerobic Mn(II) oxidation – this reaction has been well studied. The genes have been cloned and the proteins purified.
2. aerobic denitrification – denitrification is generally thought to be an anaerobic process, however, many aerobes can denitrify as well.
3. anaerobic Mn and Fe reduction – bacteria directly couple the oxidation of H₂ and organic matter to the reduction of Mn and Fe oxides for growth.
4. anaerobic NH₄⁺ oxidation – Nitrification is generally thought to be an aerobic process. But several studies have coupled NH₄⁺ oxidation to denitrification of NO₃^- to produce gaseous N products anaerobically. (e.g., NH₄⁺ + NO₃^- = N₂)
5. anaerobic HS^- and S° oxidation – chemical oxidation of HS^- by Mn + Fe oxides produces S° . S° then disproportionates to HS^- and SO₄^2- (e.g., HS^- + MnO₂ = S° = HS^- + SO₄^2-). We must not forget that phototrophic bacteria such as the green sulfur bacteria found in the Black Sea can also mediate sulfide oxidation.
6. anaerobic Fe(II) oxidation – Two types of bacteria oxidize Fe(II) anaerobically. These include denitrifying bacteria, possibly by Fe²⁺ + NO₃^- = Fe(III) + N₂, and phototrophic bacteria that use Fe(II) as an e^- donor for photosynthesis.
7. anaerobic Mn(II) oxidation – has been observed in anaerobic sand filters, apparently coupled to denitrification by Mn²⁺ + NO₃^- = MnO₂ + N₂

D. Yakushev made a combined presentation in which he presented new data and discussed some model results. The new data were collected from the R/V Akvanavt in November 1997 along a section extending from the coast at Gelendjik south toward the central part of the Black Sea. This section has been studied by the Southern Branch of Shirshov Institute of Oceanology with different periodicity for more than 20 years. This would be a good location for a future time series.

The data include hydrographic data (T, S by SeaBird CTD) and O₂, H₂S, Mn, CH₄, NH₄, NO₃ and NO₂. Sulfide increased linearly with depth below its first appearance (at s_t = 16.21) suggesting that its distribution is conservative in that layer and that a narrow zone of sulfide consumption exists at the top. Oxygen has more scatter but appears to go to zero significantly above sulfide at s_t = 15.91. NO₃, NH₄ and Mn(II) all go to zero very close to the same horizon (s_t = 16.13, 16.08 and 16.09 respectively). As for sulfide, the gradients versus depth are linear implying diffusion through the water column to narrow and intense consumption depths. These are very interesting results and they agree with those obtained on the R/V Knorr in 1988. The key density surfaces are very similar and imply there is lateral consistency in the eastern and western basins of the Black Sea.

Yakushev then discussed a sequence of geochemical source models including 1) a N + O₂ model, 2) a H₂S + N + O₂ model and 3) a Mn + H₂S + N + O₂ model. 1D and 2D hydrophysical scenarios were used to model the Black Sea oxic-suboxic-anoxic interface zone. Most of these have been published in Global Biogeochemical Cycles, Oceanology and other journals. A new model by Yakushev E.V. and E.I. Debolskaya. (in press, Particulate Manganese as a Main Factor of Oxidation of Hydrogen Sulfide in the Redox Zone of the Black Sea, in "Ocean Fronts and Related Phenomena" UNESCO Ser., IOC Workshop Reports) assigns a sinking rate to particulate Mn. The sinking rate increases as the particle size goes up. This mechanism can explain the enhanced transport of this oxidizer to the H₂S depletion point and therefore the observed distance between this level and the position of the oxicline. According to these model results, the most sensitive parameters to the hydrophysical anomalies are the concentration of Mn (IV), organic matter and S° . All of them influence the transparency.

Yakushev argued that perhaps enhanced mixing associated with Rim Current eddies plays an important role in these processes, leading to formation of Mn(IV) which can be used for H₂S oxidation in the central part of the sea. He made a plea for a more detailed study of particulate matter composition.

E. Oguz has constructed a diffusion-reaction model of the suboxic-anoxic interface zone. This model includes aerobic reactions, heterotrophic denitrification and suboxic reactions. The suboxic reactions included are:

2NO₃ + 5 Mn²⁺ + 4 H₂O = N₂ + 5 MnO₂ + 8H⁺

2NH₄⁺ + 3 MnO₂ + 4H⁺ = N₂ + 3 Mn²⁺ + 6 H₂O

HS^- + MnO₂ + 3 H⁺ = S° + Mn²⁺ + H₂O

The value of the vertical diffusivity was estimated from the vertical density gradient after Gargett (1984). The values used for the rate constants were estimated from published rate measurements. The concentrations were fixed at the upper (s_t = 15.5) and lower (s_t = 16.45) boundaries of the reaction zone. The model run allowed the elements to diffuse and react in 51 vertical levels, 1.5 m thick. Equilibrium was reached in a few years.

The results of the model resemble observations with no fine tuning.

1. There is a 5 m suboxic gap between O₂ and H₂S.
2. H₂S goes to 0 at s_t = 16.04
3. O₂ < 5 mM over the whole range of s_t
4. There is a MnO₂ maximum at about s_t = 15.97
5. There is a S° maximum at about s_t = 16.03
6. There is a N₂ maximum in the suboxic zone

Oguz concluded that the Black Sea is an ideal place to study these suboxic reactions because of their predictable occurrences. A simple diffusion-reaction model can duplicate major features but we still need direct measurements of the rates and improved estimates of vertical diffusion.

The discussion following these talks focussed on data and models needed to improve our understanding of the suboxic zone. The following items were highlighted.

Data:

1. The distributions in the suboxic zone suggest a specific set of chemical reactions between N, Mn, Fe and S species, probably mediated by microbiology. We know very little about the mechanisms, stoichiometries and rates (with and without microbiology) of these reactions.

2. We crucially need measurements of N₂, N₂O and d¹⁵N to complete a description of the nitrogen cycle in the suboxic zone.

3. We need a good seasonal time series of all concentrations and rates associated with suboxic zone problems. The distributions in the winter are almost totally unknown and this is an important gap to fill to constrain mechanisms causing the origin of the suboxic zone. Is the suboxic zone a steady state feature or does it have seasonality in response to the biological or mixing cycles?
4. We need to determine if there are horizontal gradients within the suboxic zone. Of particular importance is the concentration of particulate oxidized Mn. This is because transport of MnOx from the shelf to the interior has been proposed as a mechanism producing the suboxic zone.
5. We need to continue the deep-water time series of H₂S. There appear to be systematic changes with time that may reflect O₂ input associated with the Bosporus Inflow. Only a longer time series of reliable data can answer this.
6. We need direct measurements of vertical mixing. The vertical density gradient is so large that that the eddy diffusion coefficient may be close to the molecular diffusivity. The present approach to estimate this value from the Gargett equation is not sufficient. Mike Gregg’s recent data suggest there is no dependence of mixing on the density gradient (or N² where N = stability).
7. High-resolution distributions associated with eddies should be measured. Eddies typically have upwelling and downwelling circulation patterns and these may enhance mixing and reaction.
8. We need more detailed studies of the origin, composition and flux of particulate matter in the suboxic zone. The oxidation state of particulate Mn and Fe and the organic matter content should be determined.

Models:

1. We need measurements of suboxic zone reaction rates (in situ and in vitro) to improve the model predictions for the distributions of S, N, Mn and Fe species.
2. We need to construct 2-D or 3-D models that simulate the important horizontal processes that occur. These include a) shelf edge – open basin exchange and b) inputs associated with Bosporus Inflow and cold intermediate water (CIW) injection.
3. We need to continue to improve our ability to make elemental and electron balances across the suboxic zone.

F. Ivanov summarized how the residence times (as determined from CFC data, Lee et al, in press) increase with depth (e.g. density). He presented some simple calculations that suggest that the O₂ flux associated with the advective Bosporus inflow plume is substantial and needs to be taken into account. Bosporus inflow itself is about 300 km³y^-1 and increases by about 5 times after entrainment with cold intermediate water (CIL). The total inflow contains about 200 mM O₂ thus 4.2 x 10¹¹ M of O₂ will be injected into the suboxic and anoxic zone of the Black Sea each year.

The recent data suggest that the temperature of the CIL varies with year. In addition local convection reaches the core of the CIL about every 2^nd year. Particularly cold winter events occurred in 86/87, 90/91 and 95/96. The winter of 1993 was a cold winter and temperature in the CIL reached as low as 5.6° C.

G. Mikaelyn reviewed the seasonal succession of the ecosystem. Recent field data were displayed as E-W sections showing Nitzchia biomass and growth rate.

SeaWifs Satellite chlorophyll data was shown for 19-22 Feb and March 1998. In Feb there were a few patches with chl > 1 mg/l. In March the only high chl were along the margins. The spring bloom should be observed but is rarely seen. We need more detailed time series in the early part of the year.

He compared and summarized field data and SeaWifs data for the regions <34° E and >34E° . There was no obvious spring bloom in SeaWifs, but there was an Oct/Nov bloom. He then outlined three bloom scenarios.

1. With a shallow mixed layer (e.g. 25m) there could be a more massive bloom in February or earlier. This was illustrated in some data shown.
2. With deeper mixed layer (e.g. 40m) there would be a smaller bloom.
3. With a deeper mixed layer there would be a more classic picture with very low winter values and a large bloom in spring after development of a seasonal thermocline.

He gave some data on the size structure of the phytoplankton community. In Aug/Nov 1991 there were mostly (61-65%) nanoplankton. In Sept/Oct 1992 there were mostly (77%) microplankton. The origin of these differences was not clear but it did not appear due to nutrients.

There is no single pattern of seasonal succession. There are at least two patterns influenced by the upward flux of deep water. We urgently need data of this type and hopefully it will be studied through the NATO Linkage Grant.

Ceratium fusus is a dinoflagellate/protozoan that makes up to 30% of the phytoplankton biomass. Ceratium have an autotrophic to heterotrophic switch.

H. Yilmaz presented new data from two R/V Bilim cruises in March (1 station) and April (4 stations) 1998. Stations were located in both the rim current and central gyre.

In March the water column was well mixed down to 80m but by April the seasonal thermocline was located at 20m. For all properties there was considerable spatial variability in the depth of main features. Density proved to be a better reference horizon. Light transmission indicated a fine particle layer at s_t = 16.1 to 16.2. The suboxic zone extended from s_t=15.6 where O₂< 20 mM to s_t=16.2 where H₂S < 1 mM.

Both NO₃ and NH₄ went to zero at s_t= 16.0. NO₃ maxima corresponded to the s_t= 15.5 density surface which was observed at 70-90m in the central gyres and at 130m in the rim current region. Irradiance was measured and the depths of the 1 %, 0.1 %

0.01 % light levels were 29m (25-35m), 46m (39-50m) and 55-85m (determined

by extrapolation) respectively. The light in the suboxic zone is << 0.01%

of the surface light especially in the rim current region. Discrete chlorophyll-a values ranged from 0.1 to 1.5 mg/L. The phytoplankton biomass consisted of 93% diatoms, <2% coccoliths and 5% dinoflagellates while the abundances were 46%, 41% and 1% respectively. Integrated (down to 1 % light level) primary production values were 420, 461 and 639 mgC m^-2 d^-1 in the rim current and central gyre respectively. Based on results from spike experiments, Yilmaz suggested that N, and possibly Si, may be limiting in the Gyre Regions while P may be limiting in the Rim Current.

I. McCarthy summarized his new production measurements done on the same April 1998 Bilim cruise. This included 2 Rim Current stations and 2 eastern gyre stations.

Ammonium was measured by the low level method and values were fairly uniform and typically less than 50 nM.

Nitrate, nitrite and ammonium uptake (5-6 hr deck incubations) by plankton were determined for three time points. These were FL (first light), MD (mid day) and NT (night time). Integrated new production (1%) varied from 0.8 to 2.2 mM N m^-2 d^-1. Comparison of these values with total N uptake led to apparent f-ratios ranging from 0.18 to 0.32. The use of the f-ratio concept is open to question however. There is a quantitative nitrogen sink in the suboxic zone thus the deep water is probably not a source of N to the euphotic zone. Nitrogen fixation may be important, however no cyanobacteria were identified.

In addition McCarthy has measured the ammonium oxidation rate down to s_t = 16.2. The maximum in the rate is at s_t = 14.2. The ammonium remineralization rate was low through most of the euphotic zone and started to increase below s_t = 16.0.

In another interesting experiment, water from 0.01% light was exposed to full light levels, and the phytoplankton responded without appearing to be shocked. They were apparently not exclusively adapted to low light. No explanation was provided.

From McCarthy’s perspective what we need are data from the bloom period, measurements of PON export and an explanation for the deep viable chlorophyll.

J. Lancelot (given by E. Stanev in her absence) participated in the EROS 21 Coastal-Open Sea Exchange Project. Their study area was the NSW Shelf region, including the Danube Delta. There is extensive nutrification due to river input. There were both measurement and modeling parts of the project.

The physical modeling was done in conjunction with Stanev. The final 3-D ecosystem model results from the online coupling of the Modular Ocean Model with the ecological model BIOGEN. The later is a mechanistic ecological model of high trophic complexity (34 biogeochemical state variables assembled in five interactive modules describing the dynamics of i) phytoplankton; ii) meso- and micro-zooplankton; iii) gelatinous organisms e.g. Noctiluca Aurelia and Mnemiopsis, iv) organic matter, v) benthic). The model was first implemented by coupling it with physical models of increasing spatio-temporal complexity and running it with different human-induced forcings in order to analyze its ability to reproduce correctly historical ecological events recorded since the 1960s. Preliminary results of the performance of coupled 3-D physical-biological models were reported proving that such models are useful for predicting the dynamics of blooms.

A more complicated biological model with 34 variables was used to make simulations with Aurelia and Mnemiopsis.

Such models are useful for predicting the dynamics of blooms.

k. Oguz presented an overview of coupled-models and the general structure of such models. His most recent model is a simulation of recent changes in the Black Sea pelagic food web structure due to top-down control by gelatinous carnivores. The bottom boundary of the model is taken at the depth of 150m. There are 50 levels, each is 3m thick. The food web includes 2 phytoplankton, 2 zooplankton, bacteria, DOM, POM, a carnivore (medusae) and Mnemiopsis The data used to calibrate the model were collected off Gelendzhik in 1978 and includes phytoplankton, bacteria, microzooplankton and mesozooplankton biomass. The model simulations agreed well with the data. Competition occurs between Mnemiopsis and Aurelia and Noctiluca.

Oguz emphasized that we still need a complete annual time series of biological data. Also, in order to correctly model Mnemiopsis we need to understand its mortality term better.

l. Ozsoy presented the results of a study of mixing on the Black Sea shelf north of the Bosporus being conducted by himself and Mike Gregg (UW). Gregg measures microstructure which can be used to calculate the primary turbulence parameters ε and Χ_T . These, in turn, are used to calculate K_T and Kr. Observations were made between 16 and 18 September while observing the outflow of dense Mediterranean water from the Bosporus. Turbulent diapycnal diffusivities ranged from Kr = 10^-7 to 10^-5 N² s^-1. The average value of Kr = 1.9 x 10^-6 was only 10 times the molecular diffusivity of heat and at the lower bound of what has been reported from the open ocean. Even the background state in the open ocean, which is controlled by internal waves, is larger at

K_r = 5.0 x 10^-6 . Near the bottom, in the Bosporus inflow, values were as high as 10^-2.

The Black Sea is a unique place to study internal waves. Tides are very weak and wind is the main energy source. The natural period of the Black Sea is only 5 hours and this is too small to resonate at the frequency of daily or twice daily tides. The prediction is that internal wave intensities should be less than in the open ocean and more variable. In the open ocean as much as 50% of the mixing is due to breaking internal waves. If internal waves are less important in the Black Sea there should be much smaller mixing as well. This appears to be true based on the preliminary data.

m. Stanev discussed his GCM of the Black Sea, which includes both isopycnal and diapycnal mixing. There is a homogeneous deep layer. The model predicts annual variation in the thickness of the CIL. It can also estimate the rate of CIL formation. 1991 was a warm year and there was 7% replacement of the CIL. 1993 was a cold year and 21% of the CIL was replaced. This 21% was partitioned as follows. 32-48% comes from the shelf, 31-45% from the anticyclonic region and 21-28% from the cyclonic region.

The euphotic zone in the Black Sea has been experiencing dramatic changes. These remain poorly documented. The following items were highlighted as high priority.

1. We still need an annual cycle – time series for all physical and biological properties at least one key location. Ships of opportunity should be used if necessary. The best result would be if all contiguous countries could start at time series with at least one coastal and one gyre station.
2. We need a detailed study of the winter/spring bloom for model comparison and to distinguish between the three hypothetical bloom scenarios.
3. We need to understand the role of the deep living yet viable plankton.
4. We need measurements of POC, PON and DOC, DON export.
5. We know little of the factors determining the mortality of Mnemiopsis. This is essential for formulation accurate models for the perturbed ecosystems.
6. Direct measurements of the vertical eddy diffusion coefficient are needed

It will suffice here to note the following conclusions that have emerged from the scientific discussions:

• Major efforts are needed to understand and predict the pathways, regulation, feedbacks and the roles of physical, climatic and anthropogenic factors in driving the population dynamics and variability of the Black Sea ecosystems;
• The tools required are interdisciplinary models, continuous observations and process studies, performed with sufficient detail in recognition of the existing physical, biogeochemical interactions in the oxic, suboxic and the anoxic layers of the Basin, taking into account that these layers are strongly coupled; and
• An operational data management system is needed to assist the observational and modeling efforts.

The meeting terminated with a lengthy discussion of opportunities for future developments that can meet the scientific requirements. Taking into account the prevailing economic bottle necks in the region as well as the tasks of the existing programs, a modest initial effort for creating an observation system was identified. This involves a system of time-series stations visited on a bi-weekly basis utilizing small research vessels. These stations should be located along eight transects emanating from the locations where major research institutes are situated. The transects are to be chosen perpendicular to the coastline and they emanate from Bosporus, Sinop, Batumi, Glendjik, Malta. Odessa, Constantza and Varna with lengths of the order 100km.

Conceptually, what is proposed is similar to that of the Bermuda time-series program. The core variables to be measured include inorganic nutrients, oxygen, hydrogen sulphide, phytoplankton biomass, zooplankton biomass, chl-a, salinity and temperature. The core variables constitute a set of minimum requirements identified by both the observationalists and the modelers. They are intimately related to the issues concerning dynamics of the lower trophic levels of the biological community and eutrophication, the latter being the most dominant form of marine pollution in the region. The variables also consistent with the requirements of the ongoing research activities. Further variables can of course be measured depending on the specific interests and levels of funding available to each country.

The proposed time series program and the related modeling efforts geared towards forecasting constitute an excellent opportunity for launching the Black Sea GOOS in general, and starting up of a GOOS HOTO pilot project under this umbrella in particular. There is a strong need for training in methodology and analysis in relation to carrying out time-series measurements and data processing and exchange. There is also a need for intercalibration. Data management is a central issue. Because of the funding restraints and the nature of future GOOS in the region, the involvement of the governments in general and national authorities in particular are essential. These are matters that directly concerns IOC.

ACTION RECOMMENDED: An officers meeting of the IOC Black Sea regional Committee has been scheduled concurrently with the IOC / EC in November. A resolution can be drawn at this meeting and submitted to the EC requesting that the Black Sea GOOS be launched in 1999 at a meeting of the RC attended by high level government representatives of the riparian states. At this time a MOU for the Black Sea GOOS can be signed and the time-series program be adopted as a pilot project of the Black Sea GOOS through an additional MOU or a proof of concept exercise related to the regional GOOS MOU. Formation of a Steering Committee with members from appropriate Government agencies (as also the end users) may be highly desirable for the permanency of the Black Sea GOOS in general, and the time-series program, in particular.

It is essential to ensure that regional officials with a potential commitment to BLACK SEA GOOS attend the MOU meeting. To this end, the establishment of early contacts may be worth undertaking.

Another meeting between the EC and MOU meetings is needed to draft the scientific and implementation plans for the time-series program. Two to three scientists will be sufficient to accomplish this task since considerable discussions have already taken place in Istanbul.

James W. Murray (co-chair)

School of Oceanography

Box 357940

University of Washington

Seattle WA 98195-7940

Tel: (206) 543-4730

FAX: (206) 685-3351

e-mail: jmurray@u.washington.edu

Umit Unluata (co-chair)

Chief, Marine Pollution Research

and Monitoring Unit

Intergovernmental Oceanographic Commission

UNESCO

1, rue Miollis

75732 PARIS Cedex 15

France

Tel: (33)(1) 45 68 39 05

FAX: (33)(1) 45 68 48 12

e-mail: u.unluata@unesco.org

özden Basturk

Middle East Technical University

Institute of Marine Sciences

P.O. Box 28, Erdemli, 33731

Içel-TURKEY

Tel: 90-324-

FAX: 90-324-5212327

e-mail: ozden@ims.metu.edu.tr

Amy E. Callahan (Raporteur)

School of Oceanography

Box 357940

University of Washington

Seattle WA

Tel: (206) 543-0632

FAX: (206) 685-3351

e-mail: acallaha@u.washington.edu

Hugh W. Ducklow

School of Marine Science

Virginia Institute of Marine Science

College of William and Mary

P.O. Box 1346

Gloucester Point VA 23062-1346

Tel: (804) 642-7180

FAX: (804) 642-7097

e-mail: duck@back.vims.edu

Leonid I. Ivanov

Marine Hydrophysical Institute

Ukrainian National Academy of Sciences

2, Kapitanskaya st.

Sevastopol 335000

UKRAINE

Tel: 38 (0692) 520452

FAX: 38 (0692) 444253

e-mail: leonid@alpha.mhi.iuf.net

Sergey K. Konovalov

Marine Hydrophysical Institute

Ukrainian National Academy of Sciences

2, Kapitanskaya st.

Sevastopol 335000

UKRAINE

Tel: 38 (0692) 525276

FAX: 38 (0692) 444253

e-mail: sergey@alpha.mhi.iuf.net

Christiane Lancelot (unable to attend)

Universite Libre du Bruxelles

GMMA, CP 221, Bd. Du Triomphe

B-1050 Bruxelles

BELGIUM

Tel: 32 26505988

FAX:

e-mail: lancelot@ulb.ac.be

George W. Luther, III

College of Marine Studies

University of Delaware

700 Pilottown Road

Lewes DE 19958

Tel: (302) 645-4208

FAX: (302) 645-4007

e-mail: luther@udel.edu

Alexandre S. Mikaelyan

Head, Phytoplankton Group

P.P. Shirshov Institute of Oceanology

Nachimova prospect 36, 117851 Moscow

RUSSIA

Tel: 7-095-1245974

FAX: 7-095-1245483

e-mail: mikael@ecosys.sio.rssi.ru

James J. McCarthy

Museum of Comparative Zoology

Harvard University

26 Oxford Street

Cambridge MA 02138

Tel: (617) 495-2330

FAX: (617) 495-0506

e-mail: jmccarthy@oeb.harvard.edu

John Nevins

Museum of Comparative Zoology

Harvard University

26 Oxford Street

Cambridge MA 02138

Tel: (617) 495-5627

FAX: (617) 495-0506

e-mail: jnevins@harvard.edu

Temel Oguz

Middle East Technical University

Institute of Marine Sciences

P.O. Box 28, Erdemli, 33731

Içel-TURKEY

Tel: 90-324-5212406

FAX: 90-324-5212327

e-mail: oguz@ims.metu.edu.tr

Emin özsoy

Middle East Technical University

Institute of Marine Sciences

P.O. Box 28, Erdemli, 33731

Içel-TURKEY

Tel:

FAX: 90-324-5212327

e-mail: ozsoy@ims.metu.edu.tr

Emil Stanev

Department of Meteorology and Geophysics

University of Sofia

35 Anton Ivanov Str. 3

Sofia 1113, Bulgaria

Tel: 3592 625 6289

FAX: 3592 9625276

e-mail: stanev@phys.uni-sofia.bg

Bradley M. Tebo

Scripps Institution of Oceanography

UCSD MBRD 0202

9500 Gilman Dr.

LaJolla CA 92093-0202 USA

Tel: (619) 53-45470

FAX: (619) 534-7313

e-mail: btebo@ucsd.edu

Alan Weinstein

Associate Director Environmental Science

Office of Naval Research-International Field Office Europe

223 Old Marylebone Road

London NW1 5^TH

UK

US Address:

ONR Europe

PSC802 Box 39

FPO AE 09499 USA

Tel: 44-171-514-4964

FAX: 44-171-723-6359

e-mail: aweinstein@onreur.navy.mil

Evgeniy V. Yakushev

Southern Branch of the P.P. Shirshov Institute of Oceanology RAS

Group of Chemistry

Okeanologiya, Gelendzhik-7, 353470

RUSSIA

Tel: (86141) 23261

FAX: (86141) 23189

e-mail: yakushev@sdios.sea.ru

Aysen Yilmaz

Middle East Technical University

Institute of Marine Sciences

P.O. Box 28, Erdemli, 33731

Içel-TURKEY

Tel: 90-324-

FAX: 90-324-5212327

e-mail: yilmaz@ims.metu.edu.tr

James W. Murray (University of Washington)

Umit Unluata (IOC/UNESCO)

0900 Introduction/Arrangements

0915 Recent Research Programs (since 1988)

CoMSBlack

NATO-TU

CCMS Science Plan

New NATO Grant

Black Sea Environmental Internet Node (BSEIN)

Observations-Suboxic Zone

(~30 min presentations plus questions and discussion)

0945 Konovalov

1045 break

1100 Luther

1200 Tebo

1230 Lunch

Models –Suboxic Zone

1330 Yakushev

1430 Oguz

1530 Break

1545 Synthesis Discussion-

Data and models available and data and models needed

1730 Break for Dinner (TBA)

0900 Introduction

Observations – Euphotic Zone

0915 Ivanov

1015 Mikaelyn

1115 Break

1130 McCarthy

1230 Lunch

Models – Euphotic Zone

1330 Lancelot

1430 Oguz

1330 Ozsoy

1430 Break

1445 Stanev

1545 Synthesis Discussion-

Data and models available and data and models needed

1730 Break for Dinner (TBA)

0900 Discussion of Future Plans

- Needs of NATO Program,

- Additional NATO Proposals

- NSF Proposals

- Cruise plans

- Future Meetings

1200 Adjourn

Specifically, the goal of the BSOFS is to explore, quantify, and predict the ecosystem variability of the Black Sea—from the scale of the overall basin to the coastal/shelf areas, and over time scales extending from days to weeks to months—through the development and implementation of a forecasting and observation system. BSOFS involves coupled physical-biological-chemical-ecosystem dynamical models with interdisciplinary data assimilation schemes, linked to a flexible multiplatform, multisensor observational network; a module for designing optimum sensor-sampling configurations and specifications through theory and observations; general analysis schemes for the identification and interpretation of coupled interdisciplinary dynamical processes; and nested models integrated with sampling schemes, especially for the coastal and shelf seas.

The achievement of the BSOFS’ specific objectives will establish the feasibility of the operational system and subsequently will lead to the development of interfaces to the user communities for dissemination of forecasts. This is the preoperational goal of BSOFS.

The BSOFS is planned to be developed over a 10-year period, in three phases. The first two phases span 6 years and will be devoted to the further development of existing interdisciplinary coupled models capable of assimilating physical, biological, and chemical variables; the construction of the observational network consisting of multiple platforms and sensors capable of sampling fields of a series of key variables; and the guarantee that the system contains multiscale, nested components. The system development will rely heavily on Observation System Simulation Experiments (OSSEs) which will allow a staged and iterative build-up partly by design and partly by learning from the system behavior, making optimum use of resources, and understanding the interactions of the system components. The third phase will be devoted to the achievement of the preoperational goal of BSOFS.

A research and development program geared towards the creation of BSOFS needs coordination of its efforts with national, regional, and international programs and activities.

Organizational linkages with the IOC Black Sea Regional Committee, which was established to facilitate ocean research in the basin and to develop a regional component of the Global Ocean Observations Systems (GOOS) at an intergovernmental level will be essential. In particular, the Health of the Oceans (HOTO), Living Resources, and Coastal and Climate Modules of GOOS are expected to be instrumental in BSOFS development. A revison of the IOC-sponsored CoMSBlack Program throuh a new science plan, is expected to play a critical role in facilitating research in coastal/shelf seas and the continental margins of the Black Sea.

One of the important regional association of BSOFS development should be with the activities and programs concerning the Black Sea Strategic Action Plan in the areas of Sustainable Human Development, Living Resources Management, and Reduction of Pollution.

It is envisioned that this science plan will considerably contribute to the implementation of the Black Sea Strategic Action Plan (BS-SAP) in the following ways:

• Addressing issues not covered by BS-SAP;
• Clarifying the basic causes of environmental degradation of the Black Sea ecosystem identified in the Black Sea Transboundary Diagnostic Analysis (TDA);
• Providing a scientific basis for the action proposed in the BS-SAP;
• Helping to solve the identified problems by understanding the processes involved using models as a tool;
• Monitoring the changes in the ecosystem that will occur after the implementation of proposed actions;
• Transferring science and technology to the decision makers to take actions;
• Establishing monitoring and forecasting systems in the Black Sea on a permanent basis;
• Predicting the Black Sea response to various forms of external effects using long-term monitoring through observation systems;
• Strengthening the Black Sea scientific community; and
• Promoting and strengthening international collaboration in the region.

At an international level, BSOFS development should establish links with some existing global marine research programs. When scaled downed from the global scale to the regional dimensions of the Black Sea, BSOFS will address several of the scientific and technological issues considered by the Joint Global Ocean Flux Study (JGOFS), the Land-Ocean Interactions in the Coastal Zone (LOICZ), and the Global Ecosystems Dynamics (GLOBEC) Programs, which are implemented within the framework of the International Geosphere-Biosphere Program (IGBP). JGOFS is a multidisciplinary biogeochemical effort that focuses on the lower trophic level carbon cycling of marine ecosystems in different regions of the global ocean. Its main emphasis is on the primary production and the oceanic carbon budget. GLOBEC focuses on the zooplankton dynamics and concentrates on the carbon transfer from lower to the middle and upper trophic levels, including fish and marine mammals. One of its subprograms, the Small Pelagic Fish and Climate Change (SPACC), studies climate-induced changes in the fish production of marine ecosystems. The LOICZ program addresses the role of external forcing on coastal zone fluxes, such as sediment and nutrient input, as well as the economic and social impacts of global change on coastal zones. It also strives to make a linkage between the terrestrial, atmospheric, and marine compartments in the coastal zones that are interactive in the process being studied.

Indeed, the linkage of BSOFS to many aspects of JGOFS, GLOBEC, and LOICZ is direct. The exceptionally high volumes of nutrient loads and contaminants have resulted in considerable transformation on the lower trophic levels of the Black Sea ecosystem. The most dramatic response has been the drastic changes observed in the intensity and annual structure of the primary production and nutrient cycling. Adverse effects of all these changes are also reflected inevitably on higher trophic levels that are further perturbed by the population explosion of the gelatinous carnivores Aurelia aurita and Mnemiopsis leidyi. They were responsible for altering the food web structure as they became the main food competitor to forage mesozooplankton, fish eggs, and larvae. The most dramatic ecosystem changes have been observed on the northwestern shelf and western coastal regions of the Black Sea which are heavily influenced by anthropogenic effects from the Rivers Danube, Dniepr, and Dniestr. All these processes, anthropogenic influences, and resulting ecosystem changes, which have taken place over the last three decades, are closely interrelated with the objectives of the JGOFS, GLOBEC, SPACC, and LIOCZ.

Future environmental programs with objectives similar to those of BSOFS have not yet been developed in the Black Sea by the European Union. However, the EU-sponsored EuroGOOS is a program with which BSOFS should establish substantial linkages. More relevant is the recently developed but yet to be approved Mediterranean Forecasting Systems Program. This Program has goals and objectives that in essence are the same as those of BSOFS. In fact, the implementation program of BSOFS is developed along the lines adopted by the MFS Program. Simultaneous implementation of these two programs in these two adjacent and coupled basins of the world ocean would be rewarding from both the scientific and management points of view.

It is planned that observations will be carried out within the 'central' part of the basin in the area of predominantly cyclonic type of circulation (station 1, ~43° 30'N, 32° 30'E), over the slope or within the area of anticyclonic circulation/Sevastopol eddy (station 2, ~ 44° 20'N, 32° 50'E) and over the shelf (station 3, ~ 44° 45'N, 33° 15'E). The section is approximately 90 miles. Another 3-5 CTD soundings must be done between the stations for better resolution of the position of the Rim current and of the convergence zone.