Skip to content

Gulf of California 2015, Leg 1 – California Current

Erich Rienecker (left) and others prepare the CTD rosette for the cruise’s first cast at M1 mooring in Monterey Bay. Moss Landing can be seen in the distance.

Gulf of California 2015, Leg 1 – California Current

The 2015 Gulf of California expedition begins with a three-day transit of the R/V Western Flyer from Moss Landing to Ensenada, Mexico. On this first leg, researchers led by Senior Scientist Francisco Chavez will collect observations at a station west of the Islas Marias in the northern Eastern Pacific Warm Pool for three days. They will conduct high resolution pump sampling to study the nitrogen transformations associated with the decay of microbial phytoplankton at the top of the world’s largest oxygen minimum zone (OMZ).

Line graph showing the oxygen content in 2003 against samples taken on our last expedition in 2012. The more recent levels are significantly lower. Samples were collected at Station UC2, 80 kilometers (50 miles) due west of Pismo Beach.

As the global ocean warms, it is thought that subsurface oxygen levels will decline. Previous Gulf of California expeditions have established that along the coasts of Alta and Baja California, surbsurface waters that are the source waters for coastal upwelling have declined notably in oxygen over the past decade.

Carbon, nitrogen, and oxygen cycling in the ocean are intimately linked. As oxygen declines, carbon dioxide and nitrate increases. When oxygen reaches low levels, nitrate is used in the respiratory process.

Researchers on this leg seek to better understand the nutrient and oxygen dynamics in an oxygen minimum zone since waters in Monterey Bay are trending towards a similar condition. Their approach will be to deploy a sediment trap array and float, and follow them carrying out CTD and pump casts every four-six hours for three days.

About Gulf of California 2015, Leg 1 – California Current

The 2015 Gulf of California expedition begins with a three-day transit of the R/V Western Flyer from Moss Landing to Ensenada, Mexico. On this first leg, researchers led by Senior Scientist Francisco Chavez will collect observations at a station west of the Islas Marias in the northern Eastern Pacific Warm Pool for three days. They will conduct high resolution pump sampling to study the nitrogen transformations associated with the decay of microbial phytoplankton at the top of the world’s largest oxygen minimum zone (OMZ).