A highly toxic form of mercury could jump by 300 to 600 percent in zooplankton – tiny animals at the base of the marine food chain – if land runoff increases by 15 to 30 percent, according to a new study.And such an increase is possible due to climate change, according to the pioneering study by Rutgers and other scientists published today in Science Advances.“With climate change, we expect increased precipitation in many areas in the Northern Hemisphere, leading to more runoff,” said Jeffra K. Schaefer, study coauthor and assistant research professor in Rutgers’ Department of Environmental Sciences. “That means a greater discharge of mercury and organic carbon to coastal ecosystems, which leads to higher levels of mercury in the small animals living there. These coastal regions are major feeding grounds for fish, and thus the organisms living there serve as an important source of mercury that accumulates to high levels in the fish people like to eat.”