Posted By jngraves on 14 Jan 2015 – 11:46pm in Biological Sciences, Physical Sciences, Climate Change, Geology
A new study published in the Proceedings of the National Academy of Sciences, was led by researchers at UC Berkeley, the University of San Diego, and Yale University. The researchers assessed incidents of previous mass kills documented in scientific literature where the analysis focused on the 1940’s to the present. Their findings as reported in Science Daily, may have been skewed due to an increase in reporting of mass die-offs in recent decades, and further noted that even after accounting for some of this reporting bias, there was still a definite increase in mass die-offs for certain animals.
From the analysis, disease was found to be the primary culprit, accounting for 26 percent of the mass die-offs in the literature. Direct effects were tied to humans, such as environmental contamination which caused 19 percent of the mass kills. Biotoxicity triggered by events such as algae blooms accounted for a profound proportion of deaths, and processes directly influenced by climate such as weather extremes, thermal stress, and oxygen stress or starvation collectively contributed to about 25 percent of mass mortality events. However, the study found that most severe events were those with multiple causes.
In conclusion, the analysis found that the number of overall mass mortality events have been increasing by about one event per year over the entire 70 years the study covered. “While this might not seem like much, one additional mass mortality event per year over 70 years translates into a considerable increase in the number of these events being reported each year,” said study co-lead author Adam Siepielski, an assistant professor of biology at the University of San Diego. “Going from one event to 70 each year is a substantial increase, especially given the increased magnitudes of mass mortality events for some of these organisms.”
Biological Sciences, Physical Sciences, Climate Change, Geology