Gulf of California 2015, Leg 3 – Biodiversity and Biooptics

March 8-16, 2015

This female brooding octopus (Japetella diaphana) was observed and collected during the 2012 expedition. This species is far more abundant in the Gulf of California than in the Monterey Canyon.

This female brooding octopus (Japetella diaphana) was observed and collected during the 2012 expedition. This species is far more abundant in the Gulf of California than in the Monterey Canyon.

On this leg, researchers will study physiology and diversity of midwater animals in the Gulf of California’s central and southern basins. They are especially interested in gelatinous species which also have populations in Monterey Bay.

Many midwater species are found in both Monterey Bay and the Gulf of California, despite differences of up to 15° Celcius between the water masses. Additionally, the core of the oxygen minimum zone (OMZ) in the Gulf is five times larger than the OMZ in Monterey Bay.

The Biodiversity and Biooptics team on this leg are continuing to test their hypothesis that the unusual vertical distribution and migration patterns displayed by the gulf’s midwater fauna is driven chiefly by the characteristics of the OMZ. The research conducted will be based on dives performed by the ROV Doc Ricketts and supplemented by blue-water scuba diving and midwater trawling.


The bell of this medusa can grow up to 60 centimeters (more than half a meter) across. For more information watch: The scyphomedusa Deepstaria.

Cruise highlights

We are now even closer to La Paz and are heading down to 1,600 meters with the ROV for one last look in the deep waters of the Gulf of California. The divers have dried their gear and packed it away as there will be no blue-water dive today due to time constraints.
A sea spider (pycnogonid) was found tucked under the bell of a small jelly. Photo by Steve Haddock.

More deep-sea fauna

Rebeca Gasca writes: This is a new, exciting opportunity to work with colleagues at MBARI and other institutions, all interested in exploring the peculiar and poorly-known fauna dwelling in the water column but especially in deep waters.
We dove in Alarcón Basin today and reached the bottom at 2,675 meters with the ROV. On its way back up we observed this amazing ctenophore Aulacoctena, which happens to be very bioluminescent. However, we decided not to sample it due to its immense size; it is slightly larger than a football. As you can see it was much too large to fit into our sample cylinders without being damaged.

Hyperiid amphipods and ctenophores

Bill Browne writes: I am investigating the genetic patterns underlying animal diversity. To me, the two most interesting groups of midwater animals in the Gulf of California are the hyperiid amphipods (bug-like crustaceans) and ctenophores (comb jellies).
The bioluminescent midwater worm, Flota, lives near the seafloor, in waters over 1,500 meters deep.

Bioluminescent organisms

Darrin Schultz writes: I work in Steve Haddock's lab where I study bioluminescent organisms, animals that make their own light, much like fireflies.
Scientists take advantage of opportunities for blue-water diving to collect important samples.

Diving for jellies in Mexico

One way MBARI scientists collect specimens is by scuba diving in a small group in the deep ocean where there is no bottom in sight.
Cat Munro during a blue water dive with a salp nearby.

Siphonophore evolution and development

Cat Munro writes: I am a second year graduate student in Casey Dunn's lab at Brown University, and this is my third cruise aboard the Western Flyer. I'm interested in siphonophore evolution and development.
D724 juv vermillion lobate-350

Larvaceans, jellies, and other animals

George Matsumoto writes: My primary research interests are split between larvaceans and jellies. On the basis of MBARI's 2003 Gulf of California expedition where we found thick layers of giant larvaceans at a depth of 15 meters, I have been hoping to investigate the fluid flow patterns within the inner filters of these animals.
D723 Apolemia B nectosome-350

Exploring Farallon Basin

For today’s ROV dive we took a second look at Farallon Basin. Diving in the same location for two consecutive days gives us a chance to conduct night operations (such as trawling) and the opportunity to see how the water column changes day by day.
Some of the beautiful gelatinous zooplankton we saw on today’s dive, from top, include the siphonophores Apolemia (2,500 meters) and Erenna (1,517 meters) and the medusae Crossota (3,000 meters) and Halicreas (2,000 meters).

Research goals for the Biodiversity and Biooptics leg

The R/V Western Flyer set sail on Saturday, March 7th, at 7:00 a.m. for the third leg of the MBARI 2015 Gulf of California Expedition. Led by Steve Haddock, the science team of MBARI researchers and collaborators onboard during this leg specialize in molecular studies of "gelatinous zooplankton"—jellyfish-like siphonophores and ctenophores that can dominate midwater ecosystems.