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Biodiversity and Biooptics 2020 Expedition – Log 2

Biodiversity and Biooptics 2020 Expedition – Log 2

As with the ctenophores, siphonophores are found from the ocean surface to the seafloor. Also like the ctenophores, many siphonophores are bioluminescent which makes them prime targets for the science team to investigate. Siphonophores range in size from 10 millimeters to 30 meters (less than half an inch to almost 100 feet)—longer than a blue whale! They are important midwater predators, deploying long curtains of stinging tentacles to prey upon a variety of crustaceans and fish. These gelatinous animals are exceptionally fragile and easily fall to pieces, so they must be collected carefully with the ROV.

More information about siphonophores here.

From Alex Lapides:

While I work in Steve Haddock’s lab, I also work in the Video Lab. The Video Lab is responsible for managing the incoming video data from each ROV dive, as well as providing expert-level annotations of each organism seen on the dives. This is my first cruise since I started in the Video Lab, and I can really tell that my identification skills have been improving. It’s gratifying to have a better sense of what lives where in the water column, and to have a global knowledge of all the animals that we see. Today we dove in a deep basin in the Channel Islands of Southern California. This site is much further south than the usual dives in the greater Monterey Bay area. I was fascinated by how different the species composition was—organisms that we rarely see up north were common here, and vice versa. I appreciate being out here getting a firsthand perspective of the habitats I study, and I always look forward to my next opportunity to do so.

From Julia Chavarry:

I am interested in how human impacts influence marine food webs. I am currently investigating how often animals eat plastic, and the potential effects of climate change on deep-sea communities. The R/V Western Flyer is helping me collect species that will allow me to define their role in deep-sea food webs and the rate at which they consume plastic.

From Liz Hetherington:

I am a postdoctoral researcher in Anela Choy’s Lab at Scripps Institution of Oceanography. I am primarily interested in predator-prey relationships in open ocean (pelagic) food webs. My current research focuses on understanding the diets and feeding ecology of siphonophores, a clade of colonial hydrozoans (phylum Cnidaria). However, siphonophores, like many other gelatinous animals, are fragile. This makes it difficult to collect them, and as a result they are understudied compared to many hard-bodied animals.

During this expedition, we have collected many siphonophores using the ROV Doc Ricketts and blue-water dives. I process the samples on deck by photographing them and freezing the tissue. Primarily, I am analyzing stable carbon and nitrogen isotopes, which can give us clues about the diets and feeding ecology of these animals. I am also interested in how siphonophores fit into the overarching structure of the pelagic community. I am collecting a suite of other zooplankton and micronekton from trawl samples to examine prey available to siphonophores and overall food web structure. This research will provide insights into the ‘jelly web,’ or the gelatinous component of food webs that is understudied but likely plays an important role transferring energy through the food web.