The problem of acidification of the World Ocean and predicting the consequences for its inhabitants is becoming more and more relevant every year. The effect of short-term pH fluctuations in coastal ecosystems on the physiology of calcifying organisms—bivalves—remains poorly understood. The energy metabolism of the Black Sea mussel Mytilus galloprovincialis was investigated for the marine environment in a wide pH range, from 8.2 to 6.65. Lowering the pH to 7.0–7.5 led to a 20–25 % reduction in oxygen consumption by molluscs. At lower pH (6.54–6.7), aerobic respiration sharply decreased by 85–90 %, down to the minimum values (2.12–2.62 µgO2 /g dry/h), and the organisms transitioned to anaerobic metabolism. The metabolic response of the mussels subjected to short-term pH changes (8.2→6.65→7.2) has been investigated. The oxygen consumption of molluscs exposed at the same pH of 7.2 depended on the direction of the change in pH. Thus, in the case of pH 6.65→7.2, the respiration intensity was 30 % higher compared to the values obtained under the acidification pH 8.2→7.2. The Black Sea mussel M. galloprovincialis is shown to have the capacity for survival in the marine environment characterized by the rapid fluctuations in pH that occur during the upwelling events in the coastal areas of the Black Sea.
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Energy metabolism of Mytilus galloprovincialis under low seawater pH (in Russian)
Published 25 September 2023 Science Leave a CommentTags: biological response, Black Sea, laboratory, mollusks, physiology, respiration
Analysis of Black Sea ocean acidification
Published 1 November 2021 Science ClosedTags: Black Sea, chemistry, field
Increasing anthropogenic CO2 concentration in the troposphere causes more uptake by oceans and results in ocean acidification. Albeit, food web in the ocean, marine animals and calcifying bioata are affected negatively. Some marine species might have the possibility of extinction and some may have evolved eventually due to ocean acidification. In this study, the acidification of Black Sea is analyzed based on the pH observations made between 1990 and 2014. Sea surface pH value is found to be decreased by 0,07 and increased by 0,104 between 1990-2004 and 2005-2014 respectively. The pH annual variations also compared analytically to the annual averages of air temperature and CO2 emissions of Turkey. Both the air temperature and CO2 emission is increasing either in 1990-2004 or 2005-2014, while the rate of increase in 2005-2014 is greater than in 1990-2004. The decreasing pH (which means acidification) in 1990-2004 is found to be the reason of this difference, because some CO2 is considered to be absorbed by Black Sea. In terms of climate change, it shows that this acidification is a little bit slowing down the temperature increase over the Black Sea region while CO2 and air temperature increasing rate is less between 1990-2004 (where surface pH of Black Sea decreases) than 2005-2014.
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