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International Journal of Marine Science 2013, Vol.3, No.43, 352-360
http://ijms.sophiapublisher.com
354
the catchment area equals 2.3 mln. km
2
(UNDP, 2007).
The ratio of the catchment basin surface to the surface
of a recipient water body is called specific catchment
(SC). Higher SC suggests the catchment area that a
water body depends more on the surrounding territory
and human activity on it. The Black Sea’s SC is > 5
(2,300,000/436,400); it is a high value. For comparison
we calculated this value for the Mediterranean and
Baltic Seas – 3.39 and 4.1 respectively. This leads to
numerous anthropogenic impacts on the Black Sea
ecosystem (including its shoreline zone) and results in
a lot of environmental problems.
According to modern estimations, the length of the
Black Sea’s coastline is approximately 4,340 km
(UNDP, 2007). Zaitsev (2006) estimated that the DCL
of the Black Sea is 1.063. For comparison, the DCL of
the Sea of Azov, which is more productive than the
Black Sea, is considerably higher: 2.198. Bearing in
mind, coastline length
is a fractal value; according the
equation it depends on the scale on which we evaluate
it (Mandelbrot, 1982):
L = cK
d
where L – the coastline’s length, K – the used scale, c,
d – coefficients.
It was shown that the coefficient “d” for different parts
of the Black Sea’s coastline varies from minus 1.4 to
minus 2.4 (Shadrin, 2003). The length of coastline
between two specifies points was different if we
measure it using different scales, and if we use small
scales, on which we evaluate many biological,
physical and chemical processes, it has a much higher
value than on bigger scales. If we do not take this fact
into account it is possible to underestimate the total
production of microalgae in the shallow part of the sea
in several tenfold; underestimation of total primary
production in the Black Sea may be at about 20-50%
(Shadrin, 2003).
The Black Sea’s coastline is characterized by a variety
of types of shores: sand and gravel beaches, spits,
rocky and clay cliffs with different heights, mud flats,
muddy beaches, lagoons, etc. (Zenkovich, 1958; 1960;
Vylakanov et al., 1983; Zaitsev, 2006). Although all of
them are changing dramatically as a result of human
activities and climate change; the specific causes and
mechanisms of these changes are different (Shuisky
and Schwartz, 1988; Popescu, 1999; Ocakoglu et al.,
2002; Kosyan et al., 2012a; Shadrin et al., 2012). At
the same time, their changes do not occur
independently of each other, to some extent the entire
coastline appears to reacts as a whole system. For
example, the degradation of beaches often leads to
increases in cliff abrasion, and enhancing of cliff
abrasion can lead to the growth of beaches in other
place (Zenkovich, 1958; 1960; Kaplin et al., 1991;
Ignatov, 2004).
2 Mechanisms of the contribution of coastline
erosion to a biodiversity crisis: case studies
2.1 The Vasiljev Ravine case
Vasiljev Ravine (44.30 N; 33.35 E) is situated near
Sevastopol city and the Balaklava limestone mine
adjoins the Ravine. Waste limestone dumps from the
quarry over time accumulated and about 30 years ago
there was a huge landslide that buried the ravine and
beach (our unpublished data). A unique type of
artificial coastline was formed; an intensive erosion
and abrasion of the coastline had started here. We
observed the impacts of erosion and discharge of
slime water for 10 years as well as the experimentally
studied effects of increased concentrations of
non-toxic mineral particles of microalgae, nutrition,
behavior and reproduction of planktonic copepods.
Earlier results have been published (Shadrin and
Grishicheva, 1999; Shadrin and Litvinchuk, 2005).
Erosion and dumping led to increased concentrations
of mineral particles in coastal waters. The muddy
waters contained a high concentration of hydrophilic
limestone particles (2~50 microns in diameter). This
resulted in increased turbidity of the sea water with a
concurrent reduction in light penetration and therefore
primary production. Mineral particles also adhered to
microalgae, which caused autolysis of their cells and
also drastically decreased phytoplankton primary
production. The larger microalgal cells were affected
much more than smaller cells. This resulted in a
reduction of an average cell size in phytoplankton and
a change in the species composition.
An accumulation of these particles on the sea floor
led to mortality of all macroorganisms, and resulted
in a lifeless area of approximately 0.5 km
2
on the
sea bottom. Hydrophilic particles with the adhered
water molecules form a gel-like layer on the bottom
of the sea.