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Seafloor Ecology Expedition 2018 – Log 2

Measuring the respiration of a deep-sea sponge at Sur Ridge. The probe is attached to the arm of the Doc Ricketts.

Seafloor Ecology Expedition 2018 – Log 2


Monterey Bay National Marine Sanctuary Research Coordinator Andrew DeVogelaere

Two of the many nice things about being at sea are being rocked to sleep in your bunk by waves and the short, 30-step commute from your stateroom to the lab. This morning, launch prep began at 6:00, with a remotely operated vehicle dive starting promptly at 6:30. Because poor weather conditions were predicted by the end of the day, we canceled the plan to go farther offshore and continued research at Sur Ridge. Flexibility, plan B, plan C, and plan D are needed when working in the ocean. Today, the plan was to retrieve instruments that have been measuring deep-sea currents for the last five months, check on more of our transplanted corals, measure oxygen consumption rates in sponges, collect water samples for environmental DNA and particulate organic matter, survey the Sur Ridge communities on the southern end of the ridge, and then end the day by retrieving the benthic respirometer.

In the morning, we successfully retrieved and replaced ocean current meters. This information, along with assessing particles in water samples, will help us understand why Sur Ridge is such a spectacular place in the deep sea. Knute Brekke, an ROV pilot for 30 years who has seen deep-sea habitats around the globe said, “you’re seeing one of the most beautiful places in the world.” We want to know why this is so. This information will also help us model and predict what other areas of the deep we should protect, because we can’t visit everywhere in the world ocean with an ROV.

Just as crime scene investigators look for DNA in blood and hair samples to match with criminals and victims, environmental DNA can also be collected in ocean water samples. As sea creatures shed skin, mucus, and fecal matter DNA “leaks” from the cells floating in the water. We are learning how to detect what animals have been in an area of the ocean (over the last few days) by filtering and replicating DNA, and comparing it to known DNA sequences. On Sur Ridge, we have successfully detected DNA from humpback whales, squid, corals, sponges, and a variety of other taxa. Eventually, sending out an autonomous vehicle equipped with this technology could be the standard way to monitor and assess the health of the ocean.

In the early afternoon we focused on describing community patterns in the unexplored south-west area of Sur Ridge. We saw many more corals than expected for this relatively flat area, but none were particularly large. One of the more interesting species we saw was Asbestopluma monticolaa predatory sponge. Covered with spikes, it spears small crustaceans and slowly digests them through its outer skin. After collecting pieces of specimens for positive identification and microbial analyses, we left the bottom to successfully retrieve the benthic respirometer system.

Sur Ridge is a Sanctuary Ecologically Significant Area (SESAs), within the Monterey Bay National Marine Sanctuary (MBNMS). As the MBNMS research coordinator, I work with scientists to encourage research in these SESAs, and MBARI makes significant contributions to science and society by focusing research on Sur Ridge. In resource management decisions (for example, where bottom fishing should or should not occur), SESAs receive extra attention, and these are also sentinel areas for learning about long-term changes to deep-sea ecosystems. The chief scientist on this cruise, Jim Barry, has made Sur Ridge a “coral observatory” to understand ecosystem function and long-term changes to this spectacular habitat. Despite some limitations due to weather, this has been a spectacular cruise.