Scientists at the Earth Institute’s Lamont-Doherty Earth Observatory (LDEO) and other research institutions gathered recently for the co-sponsored ADVANCE 2009 Research Productivity Workshop. They discussed ways to conduct a large-scale natural experiment that would shed light on the impact of increases in oceanic carbon dioxide absorption on the oceanic carbon cycle in ways that studies from laboratory or outdoor enclosed-container experiments are not able to do.
Similar to the way that the global “ocean conveyor belt” could be affected by slight temperature changes or freshwater fluxes that could change the ocean circulation patterns by changing water densities, the oceanic carbon cycle or “biological pump” could be altered in response to increases in absorbed atmospheric carbon that change the ocean’s carbon chemistry and acidity, or pH level.
The study will address the question of how increased concentrations of dissolved inorganic carbon (carbon dioxide) and decreased pH in surface ocean water affect the carbon gradient between the ocean’s surface and its depths. As water on the ocean’s surface absorbs carbon dioxide, the water’s acidity increases, which can affect phytoplankton, microscopic plants that use inorganic carbon and light to produce much of the oxygen in Earth’s atmosphere. Importantly, these tiny plants form the base of the ocean food chain and ultimately support all other oceanic life, from tiny microbes to large carnivorous fish, birds and mammals.
As envisioned, the open ocean experiment would involve manipulating pH and carbonate chemistry. The workshop was intended to allow scientists to tackle logistical questions such as determining the ideal geographic location for the experiment, the timeframe of experimental inputs, and the ability to maintain a pH and control a patch of ocean for a given time. According to Veronica Lance, the postdoctoral research scientist at LDEO’s Biology and Paleo Environment Division who organized the two-day workshop, in addition to determining the approach for executing an open ocean experiment, “participants also prioritized two major oceanic regions--the subtropical Pacific and a high latitude location—as candidate locations for the experiment. Each region has specific characteristics useful for the study. The group agreed that development of a full proposal was worthwhile.”
“The meeting was successful in conceiving of a pragmatic, modified approach for executing an open ocean experiment using multiple, very large, semi-enclosed ‘mari-corrals,’” Lance reported.
The workshop was sponsored by the LDEO Climate Center, the LDEO Advisory Board Innovation Fund, and the NSF-funded ADVANCE program at the Earth Institute.