Leg 2: February 23, 2012

Day 7: Calycophoran catch of the day

Our ROV dive today took us down to 3,200 meters (10,560 feet). We spent just under an hour collecting on the bottom, then slowly made our way back up, leveling off for a short period of time every 400-500 meters (1,320-1,650 feet) to search for animals. We logged another successful 12-hour dive with all samplers filled.

We saw an unusually large abundance of red siphonophores (many different types) during today’s ROV dive.

We saw an unusually large abundance of red siphonophores (many different types) during today’s ROV dive.


The siphonophore Bargmannia lata was one of the larger animals we collected today with the detritus samplers on the ROV. The ROV pilots need to have a lot of skill and patience to maneuver the vehicle into a position where the animal is inside the acrylic container before quickly shutting the doors. With this method very fragile animals are collected with minimal disturbance.

The siphonophore Bargmannia lata was one of the larger animals we collected today with the detritus samplers on the ROV. The ROV pilots need to have a lot of skill and patience to maneuver the vehicle into a position where the animal is inside the acrylic container before quickly shutting the doors. With this method very fragile animals are collected with minimal disturbance.

Once more we observed and collected several interesting, deep squids, but the most amazing part of today’s dive was when ROV pilot Eric Martin caught a tiny calycophoran siphonophore in a detritus sampler for our science collaborator, Rebeca Gasca. After the dive the pilots and scientists gathered around to look at the specimen that was only about one centimeter long and completely transparent! Rebeca was excited to get a calycophoran in pristine shape from such a deep depth (over 3,000 meters or 10,000 feet).

From Rebeca Gasca: It has been very exciting being on this cruise, finding, watching, and collecting unfamiliar species with bizarre and sometimes beautiful forms inhabiting the depths of the Gulf of California. When you take a zooplankton net sample you think that is representative of what is there below the surface, but when you dive throughout the sea you can see how different it appears from the image you built in your mind before being right there. I could never imagine the amount and size of siphonophores with their fishing tentacles hanging and covering so much space and fishing so efficiently. Also, to look at the zooplankton in the scattering layer was interesting as we saw many ostracods, appendicularians in their “houses”, medusae, siphonophores, and other drifting animals.

Rebeca Gasca’s target animals today were siphonophores called calycophorans (what makes it a calycophoran?).

Rebeca Gasca’s target animals today were siphonophores called calycophorans (what makes it a calycophoran?).


Primno (amphipod). Photo taken in the lab by Rebeca Gasca.

Primno (amphipod). Photo taken in the lab by Rebeca Gasca.


Lensia (a calycophoran siphonophore). Photo taken in the lab by Rebeca Gasca.

Lensia (a calycophoran siphonophore). Photo taken in the lab by Rebeca Gasca.

The specimens collected with the zooplankton net and the ROV will be used to conduct taxonomical studies including comparisons between similar species of the same genus. In addition, we will perform DNA studies to get more information to accompany the morphological data that we already have for some of the groups studied, like siphonophores and amphipod crustaceans among others. At El Colegio de la Frontera Sur (ECOSUR) we have people working with several zooplankton groups that are very interested in the material we can get from this cruise. We usually have access to samples from the surface to 200 meters only, so this cruise is an opportunity to get many different species and most of the deeper specimens collected will become important additions to our collections at the Zooplankton Collection of ECOSUR in Chetumal, Quintana Roo, México.

Rebeca Gasca sorts through a dish of very small animals in the trawl catch using a dissecting microscope, looking for calycophorans and amphipods. She sketches pictures of their morphology (body shape and structure) before preserving samples for DNA analysis.

Rebeca Gasca sorts through a dish of very small animals in the trawl catch using a dissecting microscope, looking for calycophorans and amphipods. She sketches pictures of their morphology (body shape and structure) before preserving samples for DNA analysis.


Rebeca Gasca empties out a sample bucket. She is preserving many specimens to take back to El Colegio de la Frontera Sur (ECOSUR) for further observations and analyses, and for their long-term collection.

Rebeca Gasca empties out a sample bucket. She is preserving many specimens to take back to El Colegio de la Frontera Sur (ECOSUR) for further observations and analyses, and for their long-term collection.


ROV pilot Ben Erwin operates the mechanical arm that is slaved to the manipulator on the submersible from the control room on the ship.

ROV pilot Ben Erwin operates the mechanical arm that is slaved to the manipulator on the submersible from the control room on the ship.


The manipulator arm on the ROV Doc Ricketts gently lifts a benthic ctenophore off the bottom, using a repurposed kitchen spatula dubbed “The Spatulator”.

The manipulator arm on the ROV Doc Ricketts gently lifts a benthic ctenophore off the bottom, using a repurposed kitchen spatula dubbed “The Spatulator”.


Today we dove at the location marked with a pink X. Tonight we transit to the green X, which is the same location where we dove on Day 6. The scientists saw so many animals of interest that Steve Haddock decided we needed more time diving there.

Today we dove at the location marked with a pink X. Tonight we transit to the green X, which is the same location where we dove on Day 6. The scientists saw so many animals of interest that Steve Haddock decided we needed more time diving there.

The weather was calm enough that our blue-water divers were able to get into the water this afternoon as well. Four divers collected for an hour, and they came back with just one single specimen! They were shocked and disappointed at the lack of animals in the shallow waters. Fortunately, for Meghan Powers and Steve Haddock the animal they collected was one they have been targeting for luminescence research. Read more about this glowing creature tomorrow.

—Kyra Schlining

MBARI's mapping AUV, the

Equipment

Gulf of California 2012 Expedition