Expedition to the Razdolnaya River mouth and neigboring areas of Amursky Bay, Sea of Japan (East Sea)
June - September, 2005

According to the APN project schedule, Russian team conducted field-works in the Razdolnaya (Suifun) River mouth and adjacent areas of Amursky Bay. On the first stage, on June 6-13, 2005, a research expedition into the mouth area of the Razdolnaya River took place. A small research vessel "Professor Nasonov" was used to take samples of sediments, water, benthic invertebrate organisms, phyto- and zooplankton in accordance with the program developed by researchers from the Institute of Marine Biology FEB RAS. The main objective of the program was to study the influence of the Razdolnaya River runoff on the estuarine ecosystem. The research team consisted of 11 specialists from the Institute of Marine Biology and the Far Eastern Regional Hydrometeorological Research Institute, including 3 junior researchers, and 2 students from Far East State Technical University of Fisheries.

A map shows sampling sites in the mouth area of the Razdolnaya River. Water and phytoplankton samples were taken at a depth of 0 to 18 m using 5-liter batometers, and sea water temperature was measured. Quantitative samples of macrobenthos were collected with van-Veen grab (0.05 m²) and scuba-diver’s core samplers, and microbenthic infauna was taken with 20 ml plastic syringes. 5-cm surface bottom sediments were sampled for chemical analysis. Zooplankton was collected with a Juday net.

Sea water samples were analyzed to determine the following parameters: - Salinity; - Density; - pH; - dissolved oxygen; - concentrations of nutrients (phosphates, nitrites, nitrates, and silicates).

Sediment samples were analyzed to determine the following parameters: - granulometric composition; - concentration of organic carbon; - concentrations of pollutants (phenols, oil hydrocarbons, organochlorine pesticides DDT and hexachlorocyclohexane, and heavy metals Fe, Mn, Zn, Cu, Pb, Cr, Ni, Co, Cd).

Qualitative and quantitative analysis of macrobenthic and microbenthic infauna will be performed in order to study their diversity, biomass, abundance, and the species structure of bottom communities.

Qualitative and quantitative analysis of phyto- and zooplankton will be performed in order to study species composition and density.

Comparison of results with available literature data will allow us to make conclusions as to how the Razdolnaya River runoff affects the estuarine ecosystem and to predict long-term changes in the state of biota and environment in the area studied.

Schematic map showing sampling sites in the mouth area of the Razdolnaya River. The next kinds of work have been done: 1- water samples were taken for hydrological and hydrochemical analysis; 2 - zooplankton was sampled; 3 - phytoplankton was sampled; 4 - additional samples of ostracodes were taken; 5 - asterisks denote monitoring stations of the State System Control where bottom sediments and benthos were sampled for comparison of available long-term data; 6 - sediment samples for determination of granulometric composition and pollutant contents and micro- and macrobenthos samples were taken.

Intertidal group of the Amursky Bay expedition worked in estuarine zone of the bay from August 16 to September 21, 2005. In the tidal zone, 15 hydrobiological sections were made, 51 quantitative and about 20 qualitative samples of macrobenthos, and 49 quantitative samples of meiobenthos were collected. In Amursky Bay, the following areas were examined: Ugolny Cape, Tikhaya Lagoon, Tavrichansky Estuary in the area of Rechnoy Cape, Rechnoy Cape, Deviaty Val, De-Freez Peninsula, five points in Uglovoy Bight, the area of railway stations Vesenniaya, Okeanskaya, and Chaika (see the map). The following parameters were estimated on the studied area during the period of work: salinity in the range from 1‰ (Tikhaya Lagoon) to 29‰ (Tavrichanka Coast), water temperature from 16ºC (Ugolny Cape, September 21) to 30ºC (Tikhaya Lagoon, August 22). The collected material is treated by specialists in various taxonomic groups. At present, 11 Bivalvia species, 10 Gastropoda, 7 Decapoda species, 5 Polychaeta species, 4 Isopoda species, 2 Cirripedia species and 2 Pisces species have been identified. The found benthic species are typical for low-boreal region of the Far-Eastern seas of Russia.

The map of intertidal collecting sites in Amursky Bay.

Expedition of the Institute of Marine Biology on the R/V "Professor Gagarinsky" to the Amur River in July, 2005

From July 6 to 26 a group of specialists of the Institute of Marine Biology went on an expedition on the R/V "Professor Gagarinsky". They explored: the shallow-water Amur River estuary, the Tatar Strait of the Sea of Japan, and Sakhalin Bay of the Sea of Okhotsk. The expedition’s main task was to make comprehensive analysis of the present state of the Sea of Japan and Sea of Okhotsk coastal marine ecosystems locating in the areas subject to the Amur River run-off.

Over the last several years environmental situation in the Amur River catchment-basin has been critical as a result of an uncontrolled and inappropriate nature management, mainly in China and Russia. This situation initiated new ecological problems in the region and aggravated the existing ones.

There are biogeochemical barriers on a boundary between a river and a sea. These zones are known as marginal filters. A whole range of processes take place here: river flow slows down, big fractions of suspended materials settle out, clay particles coagulate, river and sea water mix and dilute each other, substances interact physically and chemically (flocculation and coagulation of organic substances and metals, sorption and desorption), and biological processes intensify. All these processes are exposed to the effects of climatic and anthropogenic changes in a river run-off. They also depend on density structure of water and on hydrodynamic conditions. Dynamics and correlations between different barriers make a paramount impact on marine ecosystems functioning.

Taking into consideration that the anthropogenic effect on the Amur River ecosystem has increased and the environment changed owing to diminution of water discharge in the river-bed, it seems reasonable to try to estimate the ability of the Amur River estuary to make changes in the Amur River run-off, as well as the estuary’s influence on the adjacent sea waters.

In this connection the expedition faced the tasks:

1. To investigate the spatial variability of hydrological and hydrochemical parameters in the zones where river and sea water mix: the Amur River, Amur River estuary, Sakhalin Bay of the Sea of Okhotsk, and the Tatar Strait of the Sea of Japan.
2. To study the peculiarities of the distribution of biogenic elements (mineral forms of phosphorous, ammonia and nitrate nitrogen, silicon and calcium) in areas with different hydrological conditions. An amount of chlorophyll a in the water surface layer was adopted as an index of productivity in the investigated areas.
3. To determine species composition, density (cells/liter), and biomass (mg/m³) of phyto- and zooplankton in the investigated areas.
4. To study quantitative and qualitative characteristics of benthic communities.
5. To collect samples of suspended materials from the water surface layer for the purpose of determining its amount and chemical composition. This enables us to draw conclusions on the removal of various substances with the river run-off, on the intensity of sedimentation and production processes, as well as to make assessment of possible anthropogenic effect.
6. To make granulometric and chemical analysis of all types of grounds and bottom sediments to determine pathways of transport of matter discharged by the river and possible anthropogenic effect on different water areas.
7. To evaluate the effect of economical activity in the Amur River catchment-basin on the concentration and distribution of dissolved and suspended forms of metals (Pb, Cd, Cu, Zn, Fe, Mn, Ni) in the adjacent sea waters.
8. To determine the peculiarities of microelement composition of water surface layer plankton in connection with the kinds and concentration of metals in the environment.

Research Manager of the project: the Academician Kasyanov, V.L., Director of the IMB, FEB RAS; the Leader of the Expedition: Nekrasov, D.A., Cand.Sc. (Biol.), Researcher of the IMB.

The expedition was organized in cooperation and with participation of:

• A group of researchers from the Pacific Oceanological Institute, FEB RAS, who conducted investigations of hydrological characteristics of the terrigenous run-off and evaluated its effect on the Far Eastern seas ecosystems, and
• A group of researchers from the Pacific Institute of Geography, FEB RAS, who studied the biogeochemical transformations of heavy metals in the coastal waters.

The Executives-In-Charge and the main participants of the project: Shulkin, V.M., Cand.Sc. (Geog.), Head of the Laboratory of the PIG, and Zhabin, I.A., Cand.Sc. (Geol.-Min.), Senior Researcher of the POI.

The research staff of the expedition comprised 8 members of the Institute of Marine Biology, 5 members of the Pacific Oceanological Institute and 2 members of the Pacific Institute of Geography - 15 people in all, including 5 Candidates of Sciences.

Hydrological, hydrochemical, geochemical, and hydrobiological work was made in the open-sea areas and in coastal zones. The researchers of the expedition were divided into three groups.

A group of hydrology and hydrochemistry made physical mensuration of water mass and collection of water samples for the purpose of evaluation hydrological and hydrochemical characteristics of marine environment in the areas studied. A geochemical group collected water and bottom sediment samples to study them and to analyze heavy metal concentrations in the ship and institute laboratories. The group also evaluated the range of suspended materials sedimentation.

A hydrobiological group collected benthic fauna samples from the board using dredgers and drags. SCUBA-divers carried out sampling of sea flora and fauna in coastal water areas. They collected water samples at different depths using bathometers, and fixed the samples to make qualitative and quantitative analysis of phytoplankton. They also carried out sampling of mero- and zooplankton with plankton nets. All the collected materials were sorted out and analyzed in the ship laboratory. The researchers made observations of sea mammals, too.

The information obtained in course of the expedition:

1) Main physical and chemical characteristics of marine ecosystems in the areas adjacent to the estuaries of big rivers;

2) Data on the species composition, number, biomass and distribution of pelagic and benthic communities of marine organisms in relation to climatic and oceanological factors;

3) Evaluation of the effect of the Amur River run-off on biological communities;

4) Data on the connection between the biodiversity of coastal flora and fauna and intensity and character of the river run-off and anthropogenic effect;

5) Data on the biota reaction to the terrigenous run-off and contaminants, transported by the river run-off.

The expedition worked in the southern part of Sakhalin Bay (Sea of Okhotsk), in the Amur River estuary, the Tatar Strait and in the areas adjacent to the estuaries of the Tumnin and Koppi Rivers (Sea of Japan). The total length of rout was 1937 nautical miles. The voyage duration was 21 days.

36 sea stations for combined research to a depth of 30 m and 3 river stations were carried out. Water samples were collected at these stations to further determine the concentrations of dissolved and suspended forms of metals. 40 profiles of temperature and salinity were obtained. 107 water samples including river water samples from the Amur, Tumnin and Koppi Rivers were analyzed to assess the amount of biogenic elements. 118 marine water samples were analyzed to determine carbonate parameters (pH, alkalinity), and equal number of samples were preserved for further analysis in the laboratories on shore to estimate calcium, magnesium, humic substances, and chlorophyll a concentrations.

More than 100 samples of macrobenthos, 99 quantitative and 34 qualitative samples of meiobenthos were collected. 35 bottom sediment samples were collected to determine granulometric composition of grounds, and equal number of samples was collected to determine the amount of organic substances and to evaluate the ratio of carbon C₁₂/C₁₃ stable isotopes. 98 bathometric, 37 plankton net and 30 bottom samples of phytoplankton, as well as 104 samples of zooplankton were collected and mounted for further analysis.

Diving equipment, dredgers, automatic hydrologic probes, bathometers, plankton nets, meiobenthos drag, cold stores, binocular microscopes, personal computers, VHF radio stations, appliances for chemical analysis, chemicals, laboratory glassware, as well as an outboard motorboat and life saving equipment were in the disposal of the expedition.

All kinds of work were done in accordance with generally adopted methods.

The information obtained as a result of the expedition will make it possible to understand the spatial variability of hydrochemical, hydrological and hydrobiological parameters, processes of destruction and production of organic matter in the zone where river and sea water mix in the Amur River estuary, as well as in the adjacent water areas of the Sea of Okhotsk (Sakhalin Bay) and the Sea of Japan (Tatar Strait). Reconnaissance work was done in the estuaries of the Tumnin and Koppi Rivers, which are the largest rivers in the south of Khabarovsky Krai flowing into the Sea of Japan.

The material results of the expedition are: the preserved benthic and plankton samples, electron tables and notes in a research log-book. Data obtained will be worked up and realized as a scientific report and scientific publications in authoritative Russian and foreign journals.

All the scheduled programs of the expedition were performed. The unique hydrological, hydrochemical and hydrobiological information was collected on the effect of the Amur River run-off on the adjacent waters of the Sea of Okhotsk and Sea of Japan in relation to natural and anthropogenic environmental factors and climatic changes.