Posts Tagged 'Black sea'

Variation in the carbon cycle of the Sevastopol Bay (Black Sea)

Continuous increase in CO2 inventory in the ocean results in dramatic changes in marine biogeochemistry, e.g. acidification. That is why temporal and spatial variabilities in atmospheric pCO2 and dissolved inorganic carbon, including CO2, pH and alkalinity in water, as well as organic and inorganic carbon in bottom sediments have to be studied together making possible to resolve the key features of the carbon cycle transformation. A 30% increase of pCO2 in the Sevastopol Bay for 2008 – 2016 evidences changes in the DIC components ratios and a significant decrease in the ability to absorb atmospheric CO2 by surface waters. High organic carbon content in the bottom sediments and predominance of organic carbon production in the biological pump at inner parts of the bay reveal ongoing transformation of the carbon cycle. This has negative consequences for recreation, social and economic potentials of the Sevastopol region.

Continue reading ‘Variation in the carbon cycle of the Sevastopol Bay (Black Sea)’

Total alkalinity and pH in the Black Sea waters in 2010 – 2011

Based on the data of the expeditionary researches of Marine Hydrophysical Institute in 2010-2011, the total alkalinity TA and pH distributions in the Black Sea waters including the Danube estuary region and the changes in the TA vertical distribution since 1988 are analyzed. It is shown that the coastal and deep-sea water TA is strongly influenced by the river flow. In the Black Sea aerobic zone, TA does not change virtually with depth and does not depend on pH. In the anaerobic zone, it weakly depends on pH, but its dependence on the hydrogen sulfide concentration is of a linear character. Comparison with the data obtained in 1988 shows that in course of the last 20 years no noticeable changes in the TA values in the Black Sea aerobic and anaerobic zones took place, whereas on the sulfide zone upper boundary the total alkalinity increased by 0.04 mg-eq*l-1.

Continue reading ‘Total alkalinity and pH in the Black Sea waters in 2010 – 2011’

Cumulative human impacts on Mediterranean and Black Sea marine ecosystems: assessing current pressures and opportunities

Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60–99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.

Continue reading ‘Cumulative human impacts on Mediterranean and Black Sea marine ecosystems: assessing current pressures and opportunities’

Had been observing the acidification of the Black Sea upper layer in XX. century?

The article’s goal is to assess the rate of acidification of the Black sea upper layer in XX century using historical data since 1924. It is shown that statistically significant century-scale acidification cannot be extracted, while decadal-scale reduction of pH has been really observing in 1960’s and between 1980 and 2000 in spite of high noise level and intense interannual pH variability. The rate of acidification for these periods reached 0.4 (0.2) pH units per decade at the surface (10 m depth). Such high level of acidification of the Black sea upper layer is mostly due not to the rise of carbon dioxide concentration in the atmosphere, but to natural quasi-periodical decadal-scale intensification of upward motions in the subsurface layer of the Black sea transporting the water with low-pH to the surface. Rough assessment of recent century-scale rate of acidification of the surface Black sea layer shows that its likely magnitude lies in the range -0.1 to -0.5 pH units per 100 years.

Continue reading ‘Had been observing the acidification of the Black Sea upper layer in XX. century?’

Ocean acidification issues in the Mediterranean and Black Seas: present status and future perspectives

The semi-enclosed Mediterranean and Black Seas have many unique oceanographic and biogeographical features which could either serve to exacerbate or reduce future effects of increased pCO2 and ocean acidification (OA). Despite the fact that these seas have been the intense focus of marine research activities for decades, few studies on the effects of OA have been carried out in the region and specific OA studies with Mediterranean species and communities are only in their infancy. The existing literature relevant to this region is reviewed, specific gaps in knowledge are identified and types of OA studies needed in the future are emphasized. Owing to the overall lack of specific OA research in the Black Sea, a marine area under severe anthropogenic and environmental stress, targeted studies on future impacts of OA on its fragile marine ecosystem are urgently needed.

Continue reading ‘Ocean acidification issues in the Mediterranean and Black Seas: present status and future perspectives’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,248,645 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book