(nitrogen and phosphorus) from land-based sources has a significant impact on the
hydrochemical conditions of environment, and as a result on the structure and
functioning of the planktonic community, as well as the benthic flora and fauna
in the coastal areas of the Black Sea (Fashchuk et al. 1991; Cociasu et al. 1996; The
Black Sea 1997; Orlova et al. 1999; Berlinsky et al. 2003; North-western part of the
Black sea: biology and ecology 2006). Thus, the assessment of primary production,
obtained in the transformed waters on offshore NWPM, in the coastal areas of
Bulgaria, Romania, Turkey, indicate a high level of primary production, the
relevant area of the eutrophic type (Cociasu et al. 1996; Demidov 2008; Finenko
et al. 2010). However, the question of the influence of anthropogenic nutrients on
the biosynthesis of primary production in the deepwater area of the Black Sea
remains open. In this regard, using the quantitative evaluation of the upward the
regeneration of phosphorus fluxes and the flux of its income from outside sources
we took an attempt to answer this question. To solve it, we, on the basis of literature
data made calculations of the average annual income of phosphorus in the Black
Sea during the period of the greatest anthropogenic load, which according to our
estimates amounted to – 74,696 tP∙year
À1 (Table 19.3). However, it is known that
on the shelf share of the NWPM is about 75% of the chemical pollution of the total
content in the river flow entering the Black Sea (Zats 1993). Total phosphorus
income from land-based sources (river runoff, industrial and domestic effluents) in
the sea water area was equal to 55,076 tP∙year
À1 (Table. 19.3). In this case, the value
of the average annual income of phosphorus in the NWPM is – 41,307 tP∙year
À1 ,
and in the coastal areas of the rest sea water can only come 13,769 tP∙year
À1 . It is
earlier established that due to the chemical and physical processes of the mineral
and organic forms of nitrogen, phosphorus, silicon is reduced by (30–50%) in the
process of transformation of water runoff from the river estuary waters and seawater barrier at the border with salinity (2–5%) with subsequent transition to the
bottom sediments (Garkavaya and Bogatova 2006). In addition, in the shelf zone of
the north-western part of the sea to the border salinity 17‰, part of phosphorus
is actively absorbed by phytoplankton and bacteria, followed by removal of sedimentation in the bottom sediments, the other part of it is removed with the stream
along the south-western coast of the Bosporus Strait and only a small part of it can
reach the deep-sea area. According to estimates (Sovga et al. 2000) from the northwestern shelf in to the deep water areas of the sea can come about 15,000 tP∙year
À1 .
Then, a potential average annual income of phosphorus in the deepwater part of the
sea will be provided by the river runoff in the amount of 13,769 tP∙year
À1 , with
precipitation – 19,620 tP∙year
À1 , entering from the north-western shelf –
15,000 tP∙year
À1 at the total value of this index – 48,389 tP∙year
À1 . Assuming
that the incoming phosphorus from these sources is distributed evenly across the
Black Sea, the annual average of his arrival in the calculation of the sea an area of
423,000 km
2 will be – 0.11 gP∙m
À2
∙year
À1 . As can be seen from Table 19.4, a key
role in phosphorus income into the photic layer of the deepwater area of the Black
Sea belongs to the regeneration and the upward fluxes, equal 97.3% of the total its
income part of phosphorus from external sources (river runoff, precipitation, stream
from the north-western part of the sea) was, only 2.7%, which potentially provides
19 Phosphorus Fluxes in the Pelagic Zone of the Black Sea
351
hydrochemical conditions of environment, and as a result on the structure and
functioning of the planktonic community, as well as the benthic flora and fauna
in the coastal areas of the Black Sea (Fashchuk et al. 1991; Cociasu et al. 1996; The
Black Sea 1997; Orlova et al. 1999; Berlinsky et al. 2003; North-western part of the
Black sea: biology and ecology 2006). Thus, the assessment of primary production,
obtained in the transformed waters on offshore NWPM, in the coastal areas of
Bulgaria, Romania, Turkey, indicate a high level of primary production, the
relevant area of the eutrophic type (Cociasu et al. 1996; Demidov 2008; Finenko
et al. 2010). However, the question of the influence of anthropogenic nutrients on
the biosynthesis of primary production in the deepwater area of the Black Sea
remains open. In this regard, using the quantitative evaluation of the upward the
regeneration of phosphorus fluxes and the flux of its income from outside sources
we took an attempt to answer this question. To solve it, we, on the basis of literature
data made calculations of the average annual income of phosphorus in the Black
Sea during the period of the greatest anthropogenic load, which according to our
estimates amounted to – 74,696 tP∙year
À1 (Table 19.3). However, it is known that
on the shelf share of the NWPM is about 75% of the chemical pollution of the total
content in the river flow entering the Black Sea (Zats 1993). Total phosphorus
income from land-based sources (river runoff, industrial and domestic effluents) in
the sea water area was equal to 55,076 tP∙year
À1 (Table. 19.3). In this case, the value
of the average annual income of phosphorus in the NWPM is – 41,307 tP∙year
À1 ,
and in the coastal areas of the rest sea water can only come 13,769 tP∙year
À1 . It is
earlier established that due to the chemical and physical processes of the mineral
and organic forms of nitrogen, phosphorus, silicon is reduced by (30–50%) in the
process of transformation of water runoff from the river estuary waters and seawater barrier at the border with salinity (2–5%) with subsequent transition to the
bottom sediments (Garkavaya and Bogatova 2006). In addition, in the shelf zone of
the north-western part of the sea to the border salinity 17‰, part of phosphorus
is actively absorbed by phytoplankton and bacteria, followed by removal of sedimentation in the bottom sediments, the other part of it is removed with the stream
along the south-western coast of the Bosporus Strait and only a small part of it can
reach the deep-sea area. According to estimates (Sovga et al. 2000) from the northwestern shelf in to the deep water areas of the sea can come about 15,000 tP∙year
À1 .
Then, a potential average annual income of phosphorus in the deepwater part of the
sea will be provided by the river runoff in the amount of 13,769 tP∙year
À1 , with
precipitation – 19,620 tP∙year
À1 , entering from the north-western shelf –
15,000 tP∙year
À1 at the total value of this index – 48,389 tP∙year
À1 . Assuming
that the incoming phosphorus from these sources is distributed evenly across the
Black Sea, the annual average of his arrival in the calculation of the sea an area of
423,000 km
2 will be – 0.11 gP∙m
À2
∙year
À1 . As can be seen from Table 19.4, a key
role in phosphorus income into the photic layer of the deepwater area of the Black
Sea belongs to the regeneration and the upward fluxes, equal 97.3% of the total its
income part of phosphorus from external sources (river runoff, precipitation, stream
from the north-western part of the sea) was, only 2.7%, which potentially provides
19 Phosphorus Fluxes in the Pelagic Zone of the Black Sea
351