Background
Climate alarmists contend that CO2-induced global warming will wreck havoc with earth's biosphere, both on land and at sea; and in light of the global warming of the 20th century, which they claim was unprecedented over the past two millennia and produced temperatures that were likewise unprecedented, one would think there would be many signs of the predicted negative impacts.  The study of Marasovic et al. provides a prime opportunity to search for such consequences in primary productivity data from the central sector of the Adriatic Sea.

What was done
Since the early 1960s, regular monthly observations of basic hydrographic, chemical and biological parameters, including primary production, have been made at two middle Adriatic oceanographic stations, one near the coast (Kastela Bay, Station 25) and one in the open part of the sea (Station 09).  The authors analyze these data and present their interpretation of them.

What was learned
Mean annual primary production in Kastela Bay was determined to be about 430 mg C m^-2 d^-1 over the period 1962-72, exceeded 600 mg C m^-2 d^-1 over the period 1972-82, and rose to over 700 mg C m^-2 d^-1 over the period 1982-96, accompanied by a similar upward trend in percent oxygen saturation of the surface water layer.  The initial value of primary production in the open sea was much less (approximately 150 mg C m^-2 d^-1), but it began to follow the upward trend of the Kastela Bay data after about one decade.

What it means
The authors state that "even though all the relevant data indicate that the changes in Kastela Bay are closely related to an increase of anthropogenic nutrient loading, similar changes in the open sea suggest that primary production in the Bay might, at least partly, be due to global climatic changes."  These changes, in their words, are "occurring in the Mediterranean and Adriatic Sea open waters" and may be directly related to "global warming of air and ocean," since "higher temperature positively affects photosynthetic processes."