Dynamics and Long-Term Changes of the Surface Parameters of Phytobenthos in the Northwestern Region of the Black Sea

Long-term changes in the amount of precipitation on the Black Sea coast of the Caucasus according to data of the hydro-meteorological stations Anapa, Tuapse and Sochi are considered. The observation data analysis of for the selected periods revealed an increase in the average yearly precipitation from the beginning of the twentieth to the beginning of the twenty-first centuries for all hydro-meteorological stations with a slight decrease in the coefficient of variation. Seasonal changes in precipitation regime are pronounced in the region. The highest increase in seasonal precipitation was noted at the Anapa hydro-meteorological station for winter, then for spring and autumn. At the Tuapse and Sochi hydro-meteorological stations also tended to increase precipitation in spring and autumn, but was noted a slight decrease in winter in the modern period. At the same time, for all seasons such growth is provided mainly by an increase in the minimum seasonal values (for all stations), as well as maximum ones in spring (for all stations) and autumn (hydro-meteorological station Anapa). In modern period relative to the twentieth century it is possible to note a slight decrease in the coefficient of variation in winter and spring (for all hydro-meteorological stations), and an increase in summer (for hydro-meteorological stations Anapa and Tuapse). The redistribution of precipitation by seasons was revealed from the beginning of the twentieth to the beginning of the twentyfirst centuries. The most significant changes affected the hydro-meteorological station Tuapse: the share of autumn and spring precipitation increased from 25 to 31 % and from 18 to 22 %, respectively, while the share of summer precipitation decreased from 26 to 18 %. The share of winter precipitation increased from the first to the third selected periods (from 30 to 35 %), after which it decreased to 29 % in the modern period.

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Modeling long-term changes of the Black Sea ecosystem characteristics

Ocean Science Discussions ◽

10.5194/osd-9-2039-2012 ◽

2012 ◽

Vol 9 (3) ◽

pp. 2039-2080 ◽

Cited By ~ 1

Author(s):

V. L. Dorofeyev ◽

T. Oguz ◽

L. I. Sukhikh ◽

V. V. Knysh ◽

A. I. Kubryakov ◽

...

Keyword(s):

Black Sea ◽

Inorganic Nitrogen ◽

The Black Sea ◽

Mnemiopsis Leidyi ◽

Biogeochemical Model ◽

Food Web Structure ◽

Decadal Scale ◽

Basin Scale ◽

Long Term Changes

Abstract. A three dimensional coupled physical-biological model is provided for the Black Sea to investigate its long-term changes under the synergistic impacts of eutrophication, climatic changes and population outbreak of the gelatinous invader Mnemiopsis leidyi. The model circulation field is simulated using the high frequency ERA40 atmospheric forcing as well as assimilation of the available hydrographic and altimeter sea level anomaly data for the 30 yr period of 1971–2001. The circulation dynamics are shown to resolve well the different temporal and spatial scales from mesoscale to sub-basin scale and from seasonal peaks to decadal scale trend-like changes. The biogeochemical model includes the main vertical biological and chemical interactions and processes up to the anoxic interface zone. Its food web structure is represented by two phytoplankton and zooplankton size groups, bacterioplankton, gelatinous carnivores Mnemiopsis and Aurelia, opportunistic species Noctiluca scientillans. The nitrogen cycling is accommodated by the particulate and dissolved organic nitrogen compartments and the dissolved inorganic nitrogen in the forms of ammonium, nitrite and nitrate. The ecosystem model is able to simulate successfully main observed features and trends of the intense eutrophication phase (from the early 1970s to the early 1990s), but points to its modification to simulate better the ecosystem conditions of the post-eutrophication phase.

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