Gulf of California 2012

February 4-13, 2012

The California Undercurrent is a poorly-described eastern boundary countercurrent, which originates in the Eastern Tropical Pacific (ETP) warm pool and flows northward along the continental slope and shelf of North America. Along its path, the CU transports water and organisms to the Monterey Bay and beyond.

Leg 1 cruise track. Click for larger version.

The waters of the CU are deficient in oxygen and nitrate but may be enriched in iron. Off central California, the CU is typically weak and subsurface during the first half of the year, but strengthens and shallows during the latter half of the year. Because the CU provides source waters for coastal upwelling, its biogeochemistry and chemical evolution have significant consequences for the overall productivity of the California Current System.

For almost 20 years, the Biological Ocean Group at MBARI has utilized moorings and ships to measure the biological and chemical characteristics of the waters in the Monterey Bay, including levels of CO₂ and dissolved inorganic carbon. Now, the Western Flyer transit south to the Gulf of California provides an opportunity for this group to trace the evolution of the Monterey Bay’s waters as they flow from the ETP to central California.

Accompanying the Biological Ocean Group is Carmen Castro of the Higher Council for Scientific Investigations in Spain. Carmen will be measuring the amount of dissolved organic carbon (DOC) in the seawater, while MBARI Research Specialist Gernot Friedrich will measure dissolved inorganic carbon (DIC). The ocean absorbs about two billion tons of CO₂ by diffusion annually, making the ocean more acidic and disrupting ocean ecosystems. This disruption could ultimately impact the oceanic carbon cycle; specifically, reducing the marine uptake of atmospheric carbon dioxide, and thus exacerbating climate change.