EAPSI: Studying the potential impacts of ocean warming and acidification on the immune response of sea urchins

Brothers Cecilia J, Birmingham AL

Investigators

Abstract

Climate-induced changes in oceanic temperature and pH are occurring rapidly around the world, and are primarily attributed to increasing levels of atmospheric carbon dioxide (CO2). As atmospheric CO2 levels rise, it is predicted that surface seawater temperatures will increase while pH will decrease. A number of recent studies have suggested that in these near-future ocean conditions, marine organisms will become more vulnerable to infectious diseases. However, no studies to date have examined the effects of both warming and acidification on the immune response of sea urchins, which are both ecologically and economically important. The intertidal sea urchin, Heliocidaris erythrogramma is commonly found in eastern Australian waters, a region that is experiencing rapid climate-induced environmental impacts. This project will investigate the prospective effects of warming and acidification on various immune system parameters of Heliocidaris erythrogramma. This research will be conducted at the University of Sydney, Australia in collaboration with Dr. Maria Byrne, an internationally-known expert on the impacts of ocean warming and acidification on marine invertebrates. Sea urchins will be exposed to treatments at current and near-future seawater temperature and pH and following three different exposure periods (1 day, 2 weeks and 4 weeks), a variety of immune parameters will be measured. These parameters will include coelomocyte (cells associated with sea urchin innate immunity) number, spreading, and adhesion, as well as the ability of coelomocytes to phagocytosis and respond to a common marine pathogen. Collectively, these measures will provide an evaluation of the ability of Heliocidaris erythrogramma to respond to immune challenges in a rapidly warming and acidifying marine environment. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.