Climate Change
Several decades of scientific research have yielded significant advances in understanding the ocean's role in regulating Earth's climate. Research at Bigelow Laboratory is largely focused on the role of marine biota in regulating the amount of greenhouse gases in our planet's atmosphere and the impact of climate change and global warming on the distribution of marine life. Of the greenhouse gases, CO² is perhaps the most important because of its links with human activities.
Marine phytoplankton are responsible for the uptake of a large part of the atmospheric CO² through photosynthesis (Balch, Matrai, Goés), which turns CO² into organic material (Balch, Goés), or through calcification (Balch) by which certain phytoplankton known as coccolithophores can transform HCO³ (in equilibrium with CO²) into calcium carbonate. Phytoplankton respiration (Matrai, Sieracki) and calcification also result in the release of CO² into the oceans. The transport of these organic and inorganic carbon particles into the deep ocean constitutes the ocean's "biological pump," and the efficiency of this pump is critical to understanding the role of ocean life in mitigating the build up of atmospheric CO² (Fields, Goés). The extent to which climate change is affecting the diversity of ocean ecosystems is being seen in the Arabian Sea (Goés). Increased dominance by phytoplankton producers of other climate-relevant gases, such as dimethylsulfide - involved in aerosol and cloud formation--may affect the biogeochemical balance of the Earth's system, both in the ocean and in the atmosphere above it.
A new area of global change that is being addressed at Bigelow Laboratory is ocean acidification (Balch), the process by which CO² from human activity is dissolving in sea water to form carbonic acid, which lowers pH (increasing acidity). Historically, only about half of the man-made CO² put into the atmosphere remains there. The other half is dissolved in the ocean. The current pH of the sea is, on average, 0.1 pH units below the pre-industrial levels. Models suggest that the pH will drop by ~0.4 pH units in the next 100 years given current trends in the increase of man-made CO². Since pH is a logarithmic scale (like the Richter scale for earthquakes), a small change reflects a larger absolute change. A decrease of pH of 0.4 units means a total increase in the hydrogen ion concentration (acidity) of 2.5 times, or 250%. It is expected that this change will affect the physiology of virtually all organisms living in the sea, from the bottom of the marine food web to the top. At present, Bigelow scientists are involved in research projects that span the entire globe, from the Gulf of Maine to the Indian, Atlantic, Pacific, Arctic and Antarctic Oceans.