Report Contents

Marine Litter in the Black Sea Region

2009

Chapter 1 - The Black Sea Environment in View of Marine Litter Problem

1. THE BLACK SEA ENVIRONMENT IN VIEW OF MARINE LITTER PROBLEM

Geographical scope of ML problem, existing in the Black Sea region, extends over the entire catchment area of the Black Sea drainage basin and includes the Black Sea proper; two satellite seas (the Sea of Azov and Marmara Sea); two straits connecting the Black Sea with the satellite seas (the Strait of Kerch and Istanbul Strait); all rivers (along with their tributaries), flowing into the above maritime areas; coastal territories bordering to these maritime areas; and all lands drained by the rivers and their confluents. In other words, the geographical scope includes those parts of Europe and Asia from which ML can arrive in or depart from the Black Sea region directly or by dint of water masses involved in the hydrologic regime of the basin. Air masses shifting over the region add to the problem of ML accumulation and dissemination.

Geographical and hydrological peculiarities of the Black Sea and contiguous water bodies have been reviewed repeatedly by many authors (e.g., Vylkanov et al., 1983; Zaitsev and Mamaev, 1997; Birkun, 2002 b; Zaitsev, 2006). Despite some factual contradictions, their general attitude on the features of these maritime areas may be summarized as follows.

1.1. PHYSICAL GEOGRAPHY

The Black Sea is one of the most isolated inland seas in the world (Fig. 1.1). It is situated between southeastern Europe and Asia Minor and has a surface area of 420,000-436,000 km² and a volume of 537,000-555,000 km³ of water. The average depth is between 1,240 and 1,315 m, though it reaches a maximum of 2,212 m. From east to west the sea measures 1,175 km, and the widest distance from north to south is over 610 km. The total length of the coastline is about 4,020-4,340 km. The seafloor is represented by the shelf, continental slope and deep-sea depression. The shelf is significantly wide (up to 200-250 km) in the northwestern part of the sea, with a depth varying from 0-160 m. In other coastal areas the shelf strip has a similar depth, but considerably less width, from 0.5-50 km. Thus, only about one quarter (24-27%) of the sea area has a depth of less than 200 m.

The shelf is slightly inclined offshore; its relief is composed of underwater valleys, canyons and terraces. The continental slope is tight and steep, descending in some places at an angle of 20-30º. Pelitic muds cover the slope and the deep-sea depression, whereas bottom pebbles, gravel, sand, silt and rocks are common for shelf area. There are few small islands in the Black Sea; the biggest one and the most distant from the mainland is the Zmeiny isle (0.18 km²) located 35 km off shore. The Crimean peninsula (27,000 km²) protrudes into the sea from the north.

At the northeastern corner, the Black Sea is connected to the Sea of Azov by the Strait of Kerch, which is 41 km long, 4-15 km wide and up to 18 m deep at its south entrance. Shallow Taman Gulf penetrates deep inland in the central section of the eastern strait's shore represented by the Taman peninsula of the Caucasus. The opposite coast of the strait is formed by the Kerch peninsula which is a constituent part of the Crimea. Sandy Tuzla island at the mouth of Taman Gulf cuts the Kerch Strait across almost in half and into north (Azov Sea) and south (Black Sea) portions.

The Sea of Azov is about 340 km long and 135 km wide with a surface area of 37,000-39,000 km² and a volume of only 320 km³. It is the world's shallowest sea with a maximum depth of 13-14 m in places. The Azov's seafloor, covered by silt and sand, has a generally flat relief. The sea is trapezoid in shape, forming at the northeast the Gulf of Taganrog, a 140-km-long creek with a depth of 0-7 m. The Arabat Spit, a 112-km-long sand bar, borders the sea at the west. A series of sandy spits is situated on the north coast of the sea. Along the shoreline of both the Black and Azov Seas, mainly on their north and west coasts and in the estuaries of rivers, there are many salty and brackish lakes and lagoons (limans), which are permanently or occasionally connected with the sea through canals and scours perforating the spits.

Fig. 1.1. Black Sea drainage basin and a list of twenty two Basin’s countries – potential contributors to Black Sea ML pollution via their river run-off (after Zaitsev and Mamaev, 1997).

In the southwest, the Black Sea is connected to the Sea of Marmara (and thus the Çanakkale Strait -otherwise known as Dardanelles Strait- and the Mediterranean) by the Istanbul Strait which is over 30 km long, 750-3,700 m wide and 37-124 m deep in the midstream. The Sea of Marmara is about 280 km long and nearly 80 km wide. It has a surface area of 11,000-12,000 km² and an average depth of 494 m, reaching a maximum of 1,355 m in the centre. The sea contains several islands forming two groups. The largest island is Marmara (129 km²) located in front of the entrance to the Çanakkale Strait.

Over 300 rivers flow into the Black and Azov Seas including the second, third and fourth major European rivers, namely the Danube, Dnieper and Don. Some rivers (Danube, Don, Kuban, Kızılırmak and Yeşilırmak) form deltas before their confluence with the sea. The Danube delta (approx 5,920 km²) is the largest wetland in the region.

According to different estimations, the total catchment area of the Black Sea drainage basin comes to 1,875,000-2,500,000 km² covering partially or entirely the territories of 22 countries (see Fig. 1.1).

1.2. HYDROLOGY

The estimated annual volume of river discharge entering the Black Sea fluctuates from 294 to 480 km³. Vast quantities of silt, nutrients, organic matter and unknown amount of ML are brought down by rivers (in particular, the Danube expels up to 52 million tonnes of sediments per year). The annual volume of atmospheric precipitations in the Black Sea area (119-300 km³) is usually lower than the volume of river inflow. The annual level of the evaporation in the Black Sea has been calculated between 232 and 484 km³. Besides this, the general water balance also depends on the intensity of water exchange through the Kerch Strait and Istanbul Strait.

There are two counter currents in the Kerch Strait: the surface current flowing from the Azov Sea to the Black Sea (22-95 km³ of water per year), and the lower one moving in the reverse direction (29-70 km³ per year). The outflow of Black Sea water through the Istanbul Strait (the surface current of 227-612 km³ per year) is approximately twice as large as the inflow from the Sea of Marmara (the lower current of 123-312 km³ per year). The horizontal circulation of Black Sea superficial waters could be roughly described as the two major ring streams rotating counterclockwise in the western and eastern parts of the basin with a velocity from 8-18 cm per second (Fig. 1.2). The smaller counterclockwise currents are also peculiar to the northwestern shelf area as well as to the Azov and Marmara Seas. The vertical circulation in the Black Sea is extremely slow – it takes hundreds of years for the waters at the surface to be replaced by near-bottom waters from the deep-sea depression. Daily tidal oscillations in the Black Sea do not exceed several centimetres. Severe storms accompanied by waves up to 5-6 m high occur most often in winter season.

Fig. 1.2. Basic scheme of superficial sea currents and main land-based sources and hot spots of marine pollution in the Black Sea region:

Taken from: Birkun (2002 b) based on Vylkanov et al. (1983), Black Sea Transboundary Diagnostic Analysis (1997), Bilyavsky et al. (1998), Kerestecioğlu et al. (1998) and Mee and Topping, (1999).

As a result of huge inflow from rivers, the mean salinity of the Black Sea (18‰) is less than a half that of the Mediterranean. It rises up to 21-27‰ at a depth below 300 m, however it falls seasonally and even as low as 2-8‰ in some spots of the northwestern area. The presence of a halocline at a depth of 100-200 m is a distinctive hydrological feature of the Black Sea. Azov's waters are lower in salinity (11.7‰ on average), being almost fresh (1-8‰) in the Gulf of Taganrog. At the same time, the waters in the Marmara Sea are more saline than in the Black Sea, averaging 22‰ at the surface with a gradual increase of salinity closer to the bottom and towards the Çanakkale Strait.

The range of water temperatures at the surface of the Black Sea extends from –1.2ºC in winter to +31ºC in summer with the mean annual level varying from 12ºC in the northwest to 16ºC in the southeast of the basin. The thermocline (7.2-8.6ºC) is situated at a depth between 50 and 150 m. The waters below 500 m have a constant temperature of about 9ºC. During frosty winters the shallow waters with low salinity become coated with ice. That is more or less typical for the northwestern coastal area and for the Sea of Azov.

The Black Sea is stratified into the superficial layer of oxygenated waters and the deeper column of anoxic waters saturated by high concentrations (0.2-9.6 mg/l) of dissolved hydrogen sulphide (H₂S). A transitional interlayer between those strata lies at a depth between 100 and 250 m with some topographic, seasonal and annual fluctuations. Thus, about 87-90% of the Black Sea water volume forms a "dead" zone unfit for aerobic life and inhabited almost exclusively by specific anaerobic bacteria. Consequently, only the upper 10-13% of the water mass represents the most suitable conditions for most marine organisms and, therefore, sustains the biodiversity.

The pronounced horizontal stratification of the Black Sea water column, caused by hydrophysical and hydrochemical factors (gradients of temperature, salinity, oxygenation and saturation with H₂S) suggests different density of water mass on the margins and within all these strata. Thus, it could be supposed that the distribution of ML is also stratified in the sea in accordance with density (or flotation ability) of different ML items. It is generally understood that the most dense ML objects sink and accumulate on the sea bottom, while the the least dense ones drift on the sea surface and in time, sooner or later, become washed ashore. The third group of ML items (probably, vastly numerous in its absolute number) is suspended in the water column between the surface and bottom. The hypothesis of ML stratification consists in selective horizontal accumulation of certain suspended ML items following the thermocline, halocline and transitional layer between the oxygenated and anoxic waters.

1.3. SOCIAL ECOLOGY AND ANTHROPOGENIC THREATS

The Black Sea is bordered by six riparian countries – by Ukraine to the north, Russia to the northeast, Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west (see Fig. 1.2). The Sea of Azov and the Kerch Strait are surrounded by Ukraine and Russia. The Sea of Marmara, Istanbul Strait and Çanakkale Strait (i.e. Dardanelles) represent the inland waters of Turkey known as the Turkish Straits System.

Most coastal territories are densely populated and even overpopulated especially during touristic season (summer). According to different estimates, based on the national census statistics, permanent human population distributed along the Black Sea shores came to 16-20 millions in the 1990s, and an extra 4-12 million per year were represented by tourists (Zaitsev and Mamaev, 1997; Bilyavsky et al., 1998; Kerestecioğlu et al., 1998). However, these figures do not include people inhabiting the coasts of the Azov and Marmara Seas, as well as the citizens of Istanbul, the largest Black Sea urban agglomeration situated on both the European and Asian sides of the Istanbul Strait and containing the resident population of around 14 million (Berkun et al., 2005) and a great number of migrants and visitors. At the end of the 20th century, total population in the Black Sea catchment area was about 160-171 millions, and the living activities of all these people in some way or other affected the Black Sea environment (Mee, 1992; Readman et al., 1999) and, presumably, contributed to ML problem.

The Black Sea and contiguous waters are used for shipping, fishing (along with a limited amount of aquaculture), mineral exploitation, tourism, recreation, military exercises and for liquid and solid waste disposal. In addition, the seabed and the catchment area are under permanent pressure from other human activities, including urban development, industry, hydro- and nuclear energetics, agriculture and land-improvement. Three principal groups of anthropogenic threats to the Black Sea environment could be listed as follows;

·               various kinds of pollution;

·               physical modification of the seabed, coasts and rivers; and

·               irretrievable direct take of natural wealth including the (over)exploitation of mineral and living resources.

Human-associated contamination of the oxygenated water layer is considered as a primary threat and the greatest environmental problem for the Black Sea region (Mee, 1992; BS SAP, 1996; Black Sea Transboundary Diagnostic Analysis, 1997; Mee and Topping, 1999). The main sources of chronic seawater pollution are represented by focal land-based outfalls, river run-off, coastal nonpoint (diffuse) sources, atmospheric fall-out, intentional and accidental inputs from vessels (Table 1.1). According to Mee (1992), the threat to the Black Sea from land-based sources is potentially greater than in any other sea of the world (see Fig. 1.2). Many coastal municipalities and industries discharge their wastes directly to the sea with inadequate or no treatment. Nevertheless, the rivers of the basin are responsible for most of the pollution (Tuncer et al., 1998). They are strongly contaminated with industrial and mining wastes (Readman et al., 1999) and transfer a huge amount of nutrients that originate primarily from agriculture (Zaitsev and Mamaev, 1997; Mee et al., 2005). The impacts of the diffuse coastal, airborne and vessel-sourced pollution are the least investigated, but believed to be significant. Irrespective of sources, anthropogenic pollution of the Black Sea is subdivided into: (a) contamination related to various chemical substances (nutrients, crude oil and petroleum products, persistent synthetic pollutants and trace elements); (b) radioactive contamination; (c) pollution by solid wastes; and (d) biological pollution including microbial contamination and introduction of alien species of marine organisms (see Table 1.1). The ML problem is originated almost completely from the problem of solid waste pollution.

Table 1.1. Types and sources of pollution in the Black Sea

^a – industrial liquid wastes and insufficiently treated or untreated sewage from coastal cities and settlements;

^b – inputs from the agriculture, industry, mining and municipal sewage from the whole Black Sea drainage area;

^c – inputs from the agriculture, animal husbandry and unmanaged tourism mainly through the run-off from land (coastal pluvial effluents and ground waters);

^d – inputs from various sources of air pollution (smokes, fumes, dust, exhaust gases) no matter where in the world;

^e – dumping of solid waste, explosives and dredged matter; discharge of untreated sewage and ballast waters; oil spills; lost fishing nets; introduction of alien marine organisms owing to the biofouling.

It is generally acknowledged that the Black Sea and its coasts are subjected to high levels of solid wastes pollution (Mee and Topping, 1999), although very few special studies of its extensiveness, sources and patterns have yet been made (see Section 5). Marine dumping had been known for all Black Sea coastal states for years although the specifically highlighted by some authors for Turkey and Georgia. (Mee and Topping, 1999; Yıldırım et al., 2004; Berkun et al., 2005). In spite of prohibition for dumping wastes in the sea currently existing in the Black Sea coastal states (except for dredged spoils) the illegal dumping still takes place. Due to specific features of very narrow strips of Georgian and Turkish coasts the problems of washing down of landfills content into the sea certainly are most severely expressed. The sites of explosive objects disposal are mapped off the Crimea (Ukraine) and in the Gulf of Taganrog (Russia). Navigation charts reflect also the distribution of sunken vessels and other scrap metal over the shelf area.

Floating ML and uncontrolled fishing nets represent particular threat to marine mammals (Zaitsev, 1998) which sometimes ingest inedible things and may get themselves entangled. A number of foreign bodies have been collected from stomachs of Black Sea common dolphins (Delphinus delphis): coal slag, pieces of wood and paper, bird feathers, cherry stones, and even a bunch of roses (Kleinenberg, 1956).

Widespread distribution of illegal, unreported and unregulated (IUU) fishing in the Black and Azov Seas can be considered as a peculiar source of ML pollution. That is true indeed regarding countless illegal nets and nets which were discarded or abandoned causing the so-called “ghost fishing”. High concentrations of fixed and floating IUU fishing gear in coastal and shelf areas result in the reduction of habitat space, formation of obstacles on migration ways and enhancement of incidental mortality (by-catch) of cetaceans, fishes and crustaceans. Although no special research on the abandoned nets has been conducted in the Black Sea region, the problem of “ghost fishing”, undoubtedly, exists at least in the northwestern Black Sea shelf area. In particular, a total of 194 dead dolphins and harbour porpoises (Phocoena phocoena) along with 18,424 turbots (Psetta maeotica), 143 sturgeons (Acipenser spp.), 401 spiny dogfishes (Squalus acanthias) and 1,359 rays (Raja clavata and Dasyatis pastinaca) were found entangled in 6,416 bottom-set gillnets approximately 640 km long which were arrested in spring 1991 in the Ukrainian waters (Birkun, 2002 a). In April 2002, 35 bycaught harbour porpoises were recorded in the abandoned illegal gill- and trammel nets (30.2 km) in the exclusive economic zone of Romania (Radu et al., 2003). Some additional information on the “ghost fishing” in the Istanbul Strait is presented in Section 5.1.1, E of this report.

1.4. MARINE AND SEASHORE AREAS OF THE BLACK SEA STATES

National Consultants on ML problem presented basic reference data regarding maritime areas and seashores of the Black Sea riparian states (Table 1.2). This information is necessary for recognizing possible spread of ML in each country and, therefore, for planning ML research, monitoring and cleanup activities at the national level. Appropriate maps and schemes can be found in Annex 2.

The National Consultants summarized also available information on the coasts which are difficult of access for the purposes of ML monitoring and cleanup operations:

Bulgaria: There are certain areas (which are high and rocky; around 50 km in total) that are difficult of access or not accessible from the beach. They are: the coast in Kaliakra, Balgarevo and Kavarna, rocky coast south of Kranevo, some areas near villages Shkorpilovci, Byala and Obzor, part of Cape Emine, coast between resort complex “Elenite” and St. Vlas; between Sozopol and Rezovska river the slopes of Strandzha Mountain form a number of small rocky capes.

Georgia: There are no municipal infrastructure and any service relevant to ML or solid waste management along the seashore between Poti and Gali (50 km; 1,8 km²), however, this section of the coast could be accessible for the most part if relevant service is established.

Romania: Inaccessible sections of the seacoast are present in the Danube delta.

Russia: Cliffy and abrupt sites, sometimes impassable, are common on the Russian Black Sea coast, particularly, round the Abrau peninsula, between capes Panagia and Zhelezny Rog, Cape Doob and Golubaya bay, Gelendzhik bay and Dzhoubga settlement as well as in the outskirts of Tuapse city (e.g., capes Guavga and Kadosh). Overall length of these difficult sections of the coast comes to 120 km. Steep coasts, which are difficult of access, are present also in the Azov Sea and Kerch Strait areas. They include lengthy sections of the northern and southern coasts of the Gulf of Taganrog (over 130 km); seashore between Dolgaya and Kamyshevatskaya spits (25 km) and between the latter one and Yasenskaya spit (20 km); some sections of the northern and southern coasts of the Taman peninsula (between Peresyp and Ilyich settlements – about 33 km, and between capes Tuzla and Panagia – 8 km). Moreover, hard-to-reach marshy coasts are peculiar to the Azov Sea and Kerch Strait area: the entire seaside of the Don delta (about 20 km); some plots of seashore of the Kuban delta (40 km); the eastern and southern coasts of Choushka spit along with other swamped sites around Taman Gulf and Dinskoy bay (25 km).

Turkey: There are coastal areas which are difficult of access (mainly the indented coastline with vertical rocky shores in places) between the Bulgarian border and Igneada (e.g., Igneada Longoz located 15 km south from Bulgaria); between Bartın and Amasra and to the east of Amasra; in the neighborhood of Cide and Doğanyurt; between Catalzeytin and Ayancik; and between Gerze and Alacam.

Ukraine: Sizeable lengths of the seacoast of the Danube delta, Dnieper-and-Boug liman, Tendrovsky, Yagorlytsky, Karkinitsky and Dzarylgachsky bays, lake Sivash, and coastal wetlands of the northern Azov Sea are difficult of access because of reedy and waterlogged shoreline in places. Besides, impassable and almost impassable sites (precipices, rocky chaoses and screes) are situated in some places round Crimea (e.g., along the Tarkhankut peninsula, capes Fiolent, Aya, Sarych, Ayudag, Meganom, Kazantip, mountains Karadag and Opuk).

Table 1.2. Characteristics of Black Sea maritime and seashore areas of the riparian countries

^a – Batumi, Poti and Supsa areas;

^b – Danube delta;

^c – Besides, Russian internal waters in the Kerch Strait and Azov Sea come to 5,370 km²;

^d – Besides, Ukrainian internal waters in the Kerch Strait and Azov Sea come to some thousands km²;

^e – The delimitation of exclusive economic zones between Russia and Ukraine in the Black Sea is expected in the future. This also concerns territorial waters of both countries in the Azov Sea and Kerch Strait (these areas and relevant depths are not included in the table);

^f – A depth of Russian internal waters in the Kerch Strait and Azov Sea does not exceed 5 and 6 m, respectively;

^g – In addition, Russian coastline and seashore area in the Kerch Strait and Azov Sea come to 460 km and 75 km²;

^h – This figure concerns the Black Sea coast only but not the Ukrainian coasts in the Kerch Strait and Azov Sea;

n.d. – no data were presented by the National Consultants.