Marine Biology

Deep Sea Expedition

Follow Dr. Shana Goffredi on her research cruise from April 17-25, 2015 to sample benthic organisms from deep-sea hydrothermal vents and hydrocarbon seeps in the Gulf of California. 


The Gulf of California (between the Baja California peninsula and mainland Mexico) is unique in that seafloor spreading occurs at ~6 cm per year along short ridge segments separated byactive transform faults, as opposed to a long continuous ridge. This presents an opportunity to examine the biological communities along these independent transform faults, which likely experience unique chemistries due to influences from both underlying geological venting and shallow subsurface biological production of gases. The seafloor in the GoC region also experiences very rapid sedimentation of organic-rich material. As a consequence, the transform faults are studded with sites of methane gas and sulfide-rich fluid seepage, hosting rich chemosynthetic bacterial and animal communities. A few of these sites were explored by us previously in 2003, and we discovered vestimentiferan tubeworms, vesicomyid clams, lepetodrilid limpets, cladorhizid sponges, foraminifera, and multi-colored bacterial mats, to name a few. In some cases, slight sediment temperature anomalies were noted, possibly the result of nearby volcanic activity. Habitat heterogeneity and patchiness were high, due to carbonate structures and animal-materials (i.e. tubes and shells), suggesting that total organismal diversity is also likely to be high and that community composition will be unique from the more well-studied hot vents to the east (GUY) and south (21°N).  During this cruise, we hope to expand our geographic sampling ranges to include sites previously identified as areas of interesting geology and chemistry, including some in the Pescadero, Farallon, and Carmen Basins at ~ 3000 m depth (from south to north; ~25°-27°N).

Our main biological questions concerning this area include :

1) Do biological communities differ between the transform faults and those along the Carmen, Farallon, or Pescadero faults, the latter of which are the most southern by 150 nautical miles (~ 25°N) and may experience influx of species from the southern hot vents.

2) Will a more thorough sampling of the smaller community members (i.e. snails, polychaetes, crustaceans) at the transform faults reveal affinities to the nearby hot vents, or a hybrid community spanning seeps and vents, as was shown for a similar hydrothermal seep off of the Costa Rica margin.

3) Is there an influence of the amount of seepage on community structure, as it diminishes with distance from the ridge crests.

4) Do other dominant invertebrate hosts (i.e. sponges, animals with epibionts) reveal bacterial symbiont differentiation on spatial and geochemical scales, as was previously observed for transform fault tubeworms.

Ship and Submersible

We’ll be aboard the RV Western Flyer, owned and operated by the Monterey Bay Aquarium Research Institute.  The Western Flyer is a 117-foot oceanographic research vessel designed specifically for deploying, operating, and recovering tethered submersibles. In order to visualize and sample the seafloor, we’ll be using the 10,000 lb remotely-operated vehicle ROV Doc Ricketts, built in 2009.








Further information about the research being conducted on this cruise will be featured in an expedition log on the MBARI website.


Track the R/V Western Flyer

April 22, 2015

Today I saw the most beautiful and mesmerizing thing that I've ever seen in nature. 

Under one volcano, there was a large flange with an upside-down reflecting pool of hot water, with tube-dwelling Alvinellid polychaetes all around the rim. We named it Glitter Lake for the fact that glittery pyrite (otherwise known as fools gold), not only lined the worm tubes, but the underneath side of the ‘lake’, which measured 5 feet in diameter, was also covered by it. Photographs do not do it justice, and video was really the only way to capture the swirling surface of the lake – which resembled an eery mist. We decided that the Alvinellid worms should be the new face of deep-sea biology. They are simply adorable, and would make a great stuffed animal. Yet, they are extreme in their love of hot venting fluids. They bother...

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April 21, 2015

Over the past 2 days we have explored some of the most spectacular vent sites we have ever seen (which is saying a lot since collectively we have at least 70 years of experience looking at these fascinating environments). 

We are currently at 23°21.462 W / 108°32.53 N in the Gulf of California. At ~2300m depth, we observed towering chimneys 100 feet tall, billowing 300 degree C water laden with minerals. We also observed large, beautiful and diffusive ‘beehive’ structures that characterized the tops of each chimney. Among the beehive structures lives one of the most heat-tolerant animals in the world - the amazing Alvinella pompejana (known commonly as pompeii worms), which wriggle in and out of their parchment tubes displaying comical feathery gills.  Among them, we noted the beautiful Hesiolyra bergi, an active, and apparently pesky, polychaete that either shares the tubes of Alvinella or muscles in on their turf....

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April 18, 2015

Today we had an incredible dive. 

We started early at 6:00 a.m. in order to make the 2 hour transit to the seafloor at ~3700 m depth.  On the previously leg of the expedition, geologists discovered this area in the Pescadero Basin and noted how different it seemed to the surrounding communities 100 miles away at 21N latitude.  We were mesmerized by the first feature we spotted – a large pagoda-like structure with upside down hot waterfalls pouring out from the sides and reflecting pools of hot water versus cold water trapped just under the flanges.  We attempted to sample the structure but it crumbled as the manipulator grabbed for it. We collected two different species of vestimentiferan tubeworms, including the famous Riftia pachytpila, which was dwarfed in numbers by the...

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April 17, 2015

At 7:03 am, we set sail aboard the RV Western Flyer on a cool overcast day off of La Paz, Mexico. Pelicans, gannets, and seagulls escort us on our way as we leave solid ground for 8 days. 

There are 11 scientists on board, all of whom specialize in various aspects of deep-sea biology, ecology, evolution, taxonomy, and microbiology.  The main goal for the expedition is to explore newly-discovered deep hydrothermal vents and seeps in the southern Gulf of California, however today we made the short 2-hour transit to a more shallow site ~ 35 miles away at ~410 meters deep. The Alfonso Basin is an area of extremely oxygen-depleted waters (measured as 0.4 umol per liter – approx. 0.2% of the conc of surface waters), which makes it interesting to compare to other sites on the seafloor. This site was explored previously in 2012 by our Chief Scientist Bob...

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