Oceanographic Expeditions

Gulf Stream Gelatinous Grazers. SCUBA and Microbiomes Sept 2019

Reconnaisance of Gulf Stream gelatinous grazers and how SCUBA dive ops could interface with sampling for microbial populations on animals surfaces and guts. We are measuring how these delicate grazers impact microbial communities at the base of the food web with the Sutherland Lab at the University of Oregon. Hurricanes and tropical storms limited the number of dives, but we collected many samples of solitary salps to bring back to the lab.

Oregon Coast Microbes and Mesozooplankton 2018-2019

We spent 10 days off the Oregon coast in Feb 2018, July 2018, and July 2019 collecting samples to measure microbial diversity across on/off shore gradients and upwelling features alongside a large effort by the Oregon State University Plankton Lab and lab of Dr. the Sutherland lab at University of Oregon. We are interested in understanding how microbial diversity shifts across environmental gradients and across different upwelling regimes in this productive coastal region. In addition, we would like to understand the very base of the food web, the microbes, and how these abundant support higher trophic levels such as larval fish, crustacean grazers, filter feeders, and other small predators.

SMILE cruise March-April 2017

One member of the lab, Kate Kouba, went to sea with a group of physical oceanographers from University of Washington's Applied Physics Laboratory (APL) to a feature of the Pacific Ocean called the North Pacific Subtropical Front (NPSF) - check out their cruise blog. The team from APL is interested in understanding the time response of the ocean's surface mixed layer to mixing driven by wind and other events such as mixed layer eddies, frontal instability and shear. It happens that Prochlorococcus is extremely abundant in this region of the ocean. Our research goals for this expedition are two:

1) As a photosynthetic cell, Prochlorococcus dynamically adjusts its pigment depending on light availability, which is related to depth. We are hoping that studying pigment concentrations in Prochlorococcus could help inform the time response of mixing events in the mixed layer, per the goals of the APL team. We will collect samples to look at single cell pigment concentrations in Prochlorococcus, examine shifts over depth, and compare to measurements of the physical dynamics of the ocean by the APL team.

2) We expect the diversity (community structure) of Prochlorococcus to be influenced by the physical dynamics of the front system. As distinct water masses come together and mix in complex ways, there may be replenishment of nutrient and energy sources for the resident microbial communities. We know Prochlorococcus prefers warmer and nutrient poor waters from the South. How will these cells compete with other phytoplankton when mixed with cooler nutrient-rich waters from the North?

Hawai'i Ocean Time-Series (HOT283 and HOT288)

These were the first cruises towards our project on measuring value of coexisting Prochlorococcus ecotypes in April and November 2016. We joined the highly efficient and capable HOT team on one of their monthly research cruises to the open ocean station ALOHA to sample aspects of the huge microbial and oceanographic system of the North Pacific Subtropical Gyre.