How does rising atmospheric CO2 affect marine organisms?

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The Aral Sea
Reference
Huang, X., Oberhansli, H., von Suchodoletz, H. and Sorrel, P. 2011. Dust deposition in the Aral Sea: implications for changes in atmospheric circulation in central Asia during the past 2000 years. Quaternary Science Reviews 30: 3661-3674.

Description
Working with a sediment core retrieved in August of 2002 from the western basin of the Aral Sea (45°58'58"N, 59°14'46"E), Huang et al. found that the history of dust deposition in central Asia can be divided into five distinct periods: "a remarkably low deposition during AD 1-350, a moderately high value from AD 350-720, a return to a relatively low level between AD 720 and AD 1400 (including the Medieval Warm Period, AD 755-1070), an exceptionally high deposition from AD 1400 to [the] 1940s, and an abnormally low value since [the] 1940s." In addition, they further found that the temporal variation in dust deposition they observed was consistent with the mean atmospheric temperature of the Northern Hemisphere during the past 2000 years, with low/high annual temperature anomalies corresponding to high/low dust presence in Aral Sea sediments, respectively. And based on the four researchers' detailed graphs of their wind intensity/dust storm data, we note that the minimum values of these inverted measures of annual temperature during the Roman Warm Period, the Medieval Warm Period and the Current Warm Period were all about the same. And it is thus quite clear that there is nothing unusual, unnatural or unprecedented about earth's current level of warmth, which is merely an expected consequence of the millennial-scale cycling of climate that is a natural expression of one of the ways in which earth's climate system operates in its particular location within our solar system and the galaxy that hosts it.