By Jack Gates
This week, the larval lab set out on the final research cruise for our EPR Biofilms 4 Larvae project! We are en route to the East Pacific Rise where the hydrothermal vents lie. While our field experiments on the relationship of microbial biofilms to larval settlement continue, masters student Mel will also be investigating a deep-sea polynoid worm, Branchipolynoe.
A summary of our work for those new to the blog:
Being dotted sometimes miles apart, locating hydrothermal vents on the vast seafloor is a big feat for a small larva. The Biofilms 4 Larvae project aims to understand the role microbial biofilms might play in helping these larvae find a place to settle. Chemosynthetic microbes are characteristic of hydrothermal vents; while plants and algae at the surface create energy from sunlight to support our ecosystems, microbes at hydrothermal vents use the mineral-rich water erupting from vents to create energy through chemical reactions. With these microbes at the heart of hydrothermal vent communities, they could be a cue for the larvae of vent species to settle. The larval lab is investigating how larval settlement is impacted by the presence of microbial biofilms.
(Sunset photo by Mel Lemke)
Our days-long transit gives us time to prepare for our experiments. Rocking back and forth with the waves in the R/V Atlantis’ main science lab, we have been busy constructing tools, measuring preservative chemicals, and reviewing dive plans. This work involves building ‘sandwiches,’ stacks of square polycarbonate plates. See Mel modelling a completed sandwich to the left.
These will be deployed on the seafloor for larvae to settle upon. Sandwiches deployed last year are waiting for us on the seafloor—these are contained in mesh ‘purses’ that keep larvae from entering but allow microbial biofilms to grow. Using the submersible Alvin, we will remove these purses and deploy microbe-less sandwiches, so we can see how larvae settle on biofilms versus on bare surfaces.
We are also building tube traps: upright cylinders that preserve any small critters descending toward the seafloor. These give us an idea of how many larvae in the water column are going toward the benthos to settle. When we arrive on site, Alvin will descend to thousands of meters depth to deploy these, alongside our sandwiches, amidst the hydrothermal vents.
Alvin will also be collecting samples. Mel is hoping to bring up Polynoids (also known as scaleworms) living inside of deep-sea mussels to investigate their ecology. In addition to studying the adults, we have a worm nursery on board for raising Polynoid larvae. Pressure vessels called HiPPOs allow larvae to be raised in the high-pressure environment they are accustomed to in the deep sea. By observing these little worms, we can better understand their development.
Temperatures are rising as we draw farther south, as is excitement as we near our first dive. We are joined by flying fish, a flock of boobies, and the occasional dolphin, each skimming the surface of the ocean. Soon, we will get to see what lies far beneath. The larval lab is excited to share the rest of our voyage with you!
Jack
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About me: I’m Jack. I’m a WWU student working in the larval lab as an REU intern. As a fan
of creatures and the ocean, I’m excited to share my experience on a deep-sea
research cruise!
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EPR Biofilms4Larvae project is a multi-institutional NSF grant: OCE-1948580 (Arellano), OCE-1947735 (Mullineaux), OCE-1948623 (Vetriani).
Also find us on Instagram! @larvallab, #Biofilms4Larvae
The Inactive Sulfides project is a multi-institutional NSF grant: OCE-2152453 (Mullineaux & Beaulieu), OCE-2152422 (Sylvan & Achberger).
Also find us on Instagram! @jasonsylvan, #LifeAfterVents
Wishing you all the best of luck, happy to see the update! Keep us posted!