Download Overview - Enclosed Coastal Seas Information

Overview ――――――――――――――――――――
The Black Sea is virtually a landlocked sea located in southeastern Europe and is bordered by six
countries – Romania, Bulgaria, Ukraine, Russia, Georgia and Turkey. Its only connection to the ocean
is through the narrow Bosphorus Strait, whereas it receives abundant freshwater from major European
rivers, such as the Danube, Dniester and Dnieper.
Location ―――――――――――――――――――――
Basic information
Surface area：423,000 km2
Volume：547,000 km3
Average depth：1,240 m
Maximum depth：2,212 m
Nature ―――――――――――――――――――――
< Background >
The Black Sea has a catchment area of over 2 million km2 that cover 22 countries including the 6
Black Sea coastal countries. The shoreline of the Black Sea is about 4,340 km long and is comprised
of a wide diversity of landscapes, such as high mountains, vast lowlands, wetlands, valleys, deltas,
cliffs and sandy beaches.1
Climate
A major part of the Black Sea experiences a Mediterranean climate, having warm humid winters
and hot dry summers. The south-eastern area is surrounded by mountains and is characterized by a
humid subtropical climate with abundant precipitation, warm winters and hot summers.2
Topography
The seabed of the Black Sea is divided into the shelf, continental slope and deep-sea depression.
The shelf occupies a large area in the north-western part of the Black Sea, where it is over 200 km
11 Black Sea
wide and has a depth ranging from 0 to 160 m. In other parts of the sea, the shelf has a depth of less
than 100 m and a width between 2.2 and 15 km.2
The continental slope is steep, descending at an average angle of 5–8°in the north–west, and in
some sections the gradient reaches 20–30°. The deep basin has a depth between 2,000 and 2,200 m,
with a maximum depth of 2,212 m.3
The depth of the Bosphorus Strait ranges from 39 to 100 m, and the width is between 0.7 and
3.5 km.2
Hydrology
The water column of the Black Sea is characterized by the presence of permanent density
stratification at a depth of around 150 m. This stratification is mainly created by the salinity
difference between the upper (18–18.5) and deeper layer (22.5). The low salinity level of the upper
layer is due to the large fresh water input (from rivers and rainfall) and also because sea water input
is limited to the narrow Bosphorus Strait. The stratification limits mixing between these two layers
and, thus, has created an anoxic environment below 150 m, with a high concentration of hydrogen
sulfide.4
Salinity of the deep layer is maintained at a constant value by the inflow of Mediterranean waters
(313 km3/yr, salinity 22), which enters the Black Sea through the Bosphorus Strait as an underflow.4
The surface layer of the Black Sea has dynamic gyres and eddies, and these systems are capable of
spreading polluted coastal waters into the offshore regions.
Sea surface temperature varies seasonally from 8℃ to 30℃, whereas the deep-layer temperature
is constantly 8.5℃.
< http://www.iasonnet.gr/abstracts/korotaev.html >
< Surrounding environment >
Wetlands
Various types of wetlands are found in the
Distribution of Wetlands in the Black Sea1
Black Sea, with limans (a type of wetland formed
by the flooding of seawater into river valleys),
lagoons,
estuaries
and
deltas
being
most
widespread. They are mainly distributed in the
delta area of large rivers, such as the Danube
(Romania),
Dnieper
(Ukraine)
and
Kuban
(Russian Federation). Relatively smaller scale
wetlands are also found along the coast of
Bulgaria, Turkey and Georgia.
These wetlands have provided productive spawning and feeding grounds for various fish species,
such as sturgeon, carp and pike-perch, which have been an important food source for the coastal
11 Black Sea
residents.
The wetlands also provide refuge for millions of waterfowl that
Red-breasted goose
migrate between the Arctic and Africa. Endangered birds, such as
slender-billed curlew, red-breasted goose and white-fronted goose,
are also found in the area.
Many ecologically significant wetlands in the Black Sea have
been designated as protected areas by the bordering countries, and
some areas are given international protection status. For example,
the Danube Delta, the largest coastal wetland complex in Europe,
< http:// www.arthurgrosset.com/
is protected by the Ramsar Convention and the World Convention
europebirds/red-breastedgoose.html >
on Natural and Cultural Heritage.3
Marine life
Although the Black Sea is only habitable for most organisms in the upper 150 m layer, the surface
water supports a rich and diverse marine life. Currently, 1,983 species of invertebrates, 168 species
of fish and 4 species of mammals have been identified. In the deep anoxic layers, some protozoa,
bacteria and invertebrate species are known to exist, but little is known about them.
Major pelagic fish in the Black Sea include sprat, whiting, anchovy and horse mackerel. Major
demersal fish include turbot and spiny dogfish. Anadromous fish, such as sturgeon, shad and blue
fish, are also found. Although the diversity of fish species has not declined, the abundance of many
species has decreased rapidly in recent decades.
Marine mammals are represented by 3 species of dolphins and the monk seal. Unfortunately
monk seals are on the verge of extinction.2, 3
History and Culture ――――――――――――――――
< History >
During the last ice age, the Black Sea was actually a large freshwater lake. Under rapid climactic
warming, glaciers began to melt quickly. Subsequently, the world’s oceans and seas started to rise. Around
5,600 BC, it is believed that the Mediterranean Sea broke through a land “dam” at present-day Istanbul,
creating the short and narrow (about 2km wide) Bosporus Strait and allowing vast amounts of seawater to
flow into the previously fresh waters of the Black Sea.
Over the last few years, several scientists have argued that the gushing of water from the
Mediterranean into the Black Sea was so rapid and extensive that it could have been linked to such
well-known flood legends as the Sumerian epic of Gilgamesh and even the Biblical account of Noah’s
flood.
In recent research undertaken by the National Geographic Society, core samples from the bottom of the
Black Sea indicated that a white or light color, typical of lake-mud, characterizes the deep sediments,
11 Black Sea
whereas the upper black layers indicate an iron-sulfide-containing mud found in marine environments. In
addition, the study found that mollusk shells trapped in those same layers change from freshwater types in
the deep sediments to saltwater varieties in the more recently deposited top layers. These sediments show a
rapid transition from freshwater to marine, further supporting theories of fast and violent changes over just
a few years, as opposed to a much more gradual filling of the Black Sea.
Researchers studying the Black Sea have suggested that huge numbers of people living near the shores
of the Black Sea prior to its saltwater invasion would have been forced inland by the rapid flooding,
perhaps then colonizing new areas of Europe, Asia, and Africa.
< http://www.ocean.udel.edu/blacksea/history/noah.html >
Social Environment
――――――――――――――――
< Population>
The Black Sea coastal zone is densely populated, with approximately 16 million inhabitants and 4
million tourists visiting the coast over the summer seasons. The population is most concentrated along
the coastal area of Turkey and Ukraine, with approximately 6.7 million and 6.8 million people residing
in these areas, respectively.2
< Land use >
The majority of the coastal and inland area is
Land use in the Black Sea Region1
dominated by agricultural land, especially in the
lowlands of Romania, Ukraine and Russia. Extensive
forests and woodlands are found along the steep
northeast coast of Russia and Georgia.1
< Industry >
Agriculture is one of the most important industries
in the Black Sea region and it is the principal industry
for all Black Sea coastal countries. Other major
industries include mining, oil, manufacturing (machine,
textiles, chemicals and so on), fisheries, timber and tourism.
< http://www.ocean.udel.edu/blacksea/geography/ >
Agriculture
A wide range of agricultural products are produced in Black Sea coastal countries, including
wheat, sugar beets, vegetables, tea, fruit, beef, sheep and so on.
< http://www.ocean.udel.edu/blacksea/geography/ >
11 Black Sea
Fisheries
Fisheries in the Black Sea have rapidly declined over the past two decades due to the decline in
fish abundance. The total catch has fallen from 814,000 tons in 1988 to 213,000 tons in 1991,
although it increased to 523,000 tons by 2001. Furthermore, only six of the 26 fish species
commercially exploited in the 1960s remain in commercial quantities. Major species that are no
longer commercially exploited include mackerel, bonito, bluefish, tuna, swordfish and sturgeons.
Currently, anchovy is the most important commercial species in the Black Sea, followed by sprat,
horse mackerel, whiting and mullet.
The main causes behind the fishery collapse are thought to be eutrophication, the introduction of
alien species and overfishing.3
< http://www.unep.zorg >
Environmental Problems
――――――――――――――
<Water and sediment quality>
The water quality of the Black Sea has seen a steady decline over the past decades, the most
significant being eutrophication. Eutrophication has drastically altered the Black Sea ecosystem by
creating hypoxic conditions and killing many bottom-dwelling organisms in the process. It has also led
to the destruction of massive meadows of the red algae genus Phyllophora in the northwest Black Sea,
and organisms that were dependant on these algae have been heavily affected. Between 1973 and 1990,
an estimated 60 million tons of bottom-dwelling animals were killed in the northwest coast, including
5 million tons of fish.5
Another major threat to the Black Sea waters comes from oil pollution.
Other toxic substances commonly found in enclosed seas, such as pesticides and trace metals, have
not been recorded in significant amounts and are not yet considered as significant environmental
threats.5
Eutrophication
In the Black Sea, nitrogen and phosphorus compounds are the main nutrients triggering
eutrophication.
The majority of nutrients discharged into the Black Sea come from the international rivers,
especially the Danube. Over 50% of the nitrogen and 60% of the phosphorus discharged into the
Black Sea come from the Danube. About half of the nutrients anthropogenically introduced into the
Danube originate from agriculture, one quarter originate from industry and the other quarter
originate from domestic sources.4, 5
At the country level, about 70% of the nitrogen and phosphorus discharged into the Black Sea
originate from the 6 Black Sea coastal countries. The remaining 30% comes from other countries in
the Black Sea catchment area.4
11 Black Sea
Within the Black Sea coastal countries, Romania is the greatest contributor of nitrogen and
phosphorus, which is mainly discharged via the Danube.4
Due to the economic collapse of most lower Danube and former Soviet countries over last
decade, and the development of new measures to reduce nutrient discharge, nutrient levels of the
Danube River have recently decreased, with phosphate levels now being roughly the same as in the
1960s. However, the nitrogen level is still high, being roughly 4 times the level observed in the
1960s.5
Total Nitrogen Input to Black Sea (kt/year)
Total Phosphorus Input to Black Sea (kt/year)
16
250
12
200
(kt)
(kt)
150
8
100
4
50
0
0
Bulgaria
Romania
Ukraine
Russian
Fed.
Georgia
Turkey
Bulgaria
Other
countries
Romania
Ukraine
Russian
Fed.
Georgia
Turkey
Other
countries
Oil pollution
Currently, levels of oil pollution are not
Oil Inputs to the Black Sea1
high in the open Black Sea but are
60,000
river mouths. Approximately 110,000 tons
50,000
of oil enters the Black Sea each year, with
approximately 53,000 tons coming from the
Danube River. The remainder comes from
domestic sewage (30,000 tons), industry
(15,500 tons), land-based sources and other
Oil input (tons)
unacceptable in many coastal areas and
40,000
Domestic
Industrial
Land-based
Other rivers
Danube River
Accidental oil spills
30,000
20,000
10,000
0
Bulgaria
Georgia
Romania
Russia
Turkey
Ukraine
Total
rivers of Black Sea coastal countries. The amount of oil discharged from accidental oil spills is
relatively minor, at approximately 110 tons per year. However, the risks of accidental oil spills are
rising due to increasing tanker traffic. In 1995, almost 1,500 tankers navigated through the
Bosphorus Strait.1, 5
< Other Environmental Problems >
Introduction of exotic species
Since the beginning of the 20th century, 26 exotic species have been introduced either
accidentally or intentionally into the Black Sea, significantly altering and damaging the ecosystem
in the process. For example, the voracious predatory sea snail, Rapana thomasiana, arrived from
11 Black Sea
Japan in the mid-1940s and devastated the Black Sea oyster beds.
Mnemiopsis leidyi
In the mid-1980s, the comb jelly, Mnemiopsis leidyi, was
introduced into the Black Sea via ship ballast water and, without
any predators, flourished in the eutrophic Black Sea environment.
By 1990, its numbers reached about one billion tons, which is
more than the world’s total fish catch. The species dramatically
changed the Black Sea ecosystem by consuming vast amounts of
zooplankton and fish larvae, which consequently led to the collapse
of certain fish stocks. Recently, there has been some recovery of the
ecosystem but the invader is still present in large numbers.5
< http://tolweb.org/tree/
phylogeny.html >
< Environmental Protection Measures >
Convention on the Protection of the Black Sea Against Pollution (Bucharest Convention)
Recognizing the drastic decline of Black Sea vitality, the six coastal countries signed the
Convention on the Protection of the Black Sea Against Pollution in Bucharest, Romania, in April
1992 (the Bucharest Convention), which provides a legal and diplomatic platform for joint action.
Subsequently, the Black Sea Environmental Programme (BSEP) was established in June 1993. This
laid the foundations on which the six countries, together with international donors, undertook an
extensive evaluation of the Black Sea environment, leading to the development of the Black Sea
Strategic Action Plan that was agreed to in October 1996 and which became fully operational in
October 2000. This Plan contains some 59 specific commitments regarding measures to reduce
pollution, improve management of living resources, encourage human development in a manner that
does
not
prejudice
the
environment
and
take
steps
toward
the
financing
of
environmental-improvement projects.
As a common regional decision-making body charged with implementing the Convention and
Action Plan, the Commission for the Protection of the Black Sea Against Pollution (Black Sea
Commission) has been established in Istanbul. Members of the Commission are comprised off
senior officials from the environmental agency of each of the six signatories. Also, a system of
Advisory Groups and associated Regional Activity Centres has been established in each country to
provide advice and perform practical technical work.
The commitment of the Black Sea countries to continue complying with provisions of the
Bucharest Convention was reconfirmed in the Ministerial Declaration adopted during the meeting of
environment ministers from all six countries in Sofia, June 2002. At this meeting, the Strategic
Action Plan was revised and agreed to, and a new Protocol to the Convention was signed regarding
the protection of biodiversity in the region.2
Black Sea Ecosystems Recovery Project
In May 2002, with support from the Global Environment Facility (GEF), the Black Sea
11 Black Sea
Ecosystems Recovery Project was established. The project will provide a range of legal and policy
instruments for tackling the problems of eutrophication and the release of certain hazardous
substances, and to facilitate ecosystem recovery.2
Black Sea Danube River Basin Task Force
The Danube River plays a key role in the deterioration of the Black Sea. To seek close
cooperation with the Danube River basin management bodies a Memorandum of Understanding was
recently signed between the Black Sea Commission and the International Commission on the
Protection of the Danube River. A Task Force (Black Sea Danube River Task Force) was
subsequently established, under the auspices of the European Commission, to prepare and
implement a strategy to invest in projects designed to reduce pollutant discharges to the Danube
River that ultimately end-up in the Black Sea.2
Related organizations and NGO
The BSEP provides support to more than 25 environmental non-government organizations
(NGOs) for activities, such as building public awareness and promoting education on Black Sea
environmental issues, restoring coastal wetlands, tracking implementation of governmental
commitments, monitoring environmental ‘hot spots’, promoting alternative agricultural practices for
minimizing excessive use of fertilizers, estimating soil erosion; and advocating low-cost sewage
treatment technologies.2
・Black Sea NGO Network – A regional association of NGOs concerned with the Black Sea
environment < http://www.bseanetwork.org/ >
・Agreement for the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and
Contiguous Atlantic Area (ACCOBAMS) – An organization dedicated to the conservation of
cetaceans in the Black Sea and Mediterranean Sea. < http://www.accobams.mc/ >
References ――――――――――――――――――――
1. BSEP, 1997. Black Sea Transboundary Diagnostic Analysis. Istanbul, Turkey.
2. Black Sea Commission, 2002. The State of the Environment of the Black Sea: Pressures and Trends
1996-2000. < http://www.blacksea-commission.org/Publications/SOE_English.htm >
3. BSEP, 1997. Biological Diversity in the Black Sea: A Study of Change and Decline. Black Sea
Environmental Series Vol. 3.
4. BSEP, 1998. Black Sea Pollution Assessment. Black Sea Environmental Series Vol. 10
5. Mee, L.D. How to save the Black Sea: Your guide to the Black Sea Strategic Action Plan (Brochure).
BSEP.