We will need to keep R/V Falkor at the dock for a few more weeks to work through some unplanned technical engineering issues. This unfortunately means that Falkor will not be headed into the Gulf of Alaska

North Pacific Octocorals

Some of the Ocean’s most iconic and alien-looking species are found in the Bathyal zone, 800 to 4000 meters deep. Known as the midnight zone due to its complete darkness, strange bioluminescent organisms, beings with huge teeth, and other bizarre adaptations make this little to no light habitat home. The obscurity of the bathyal zone has made it one of the least well-known sectors of the ocean, something that Dr. Les Watling from the University of Hawaii and his research team will strive to overcome during their summer expedition on Falkor.

The bathyal zone is also home to much of the deep sea coral diversity, particularly octocorals. Octocorals are colonial organisms formed by numerous tiny animal “polyps” with eight tentacles. In deep-waters, octocorals are among the largest invertebrates and provide optimal environments for associated invertebrates and fish. These habitats are targeted by fishing trawlers who will drag nets across octocoral environments. Little is known about fishing impacts to these remote and deep regions. During the expedition, scientists will collect high resolution video with ROV SuBastian that will help fisheries commissions and other management authorities identify vulnerable habitat. In addition to video, reliable biogeographic data will help to asses octocoral distribution, which can be used for natural resource management and policy making.

Onward to Emperor

Previous bathyal fauna like octocorals have been sampled along the Aleutian Islands off northern Japan and on parts of the Hawaiian Ridge. Scientists have found significant differences in the organisms living in these locations and suspect that currents play a role in this distribution. One current in particular may play the most important role in coral distribution, the North Pacific Intermediate Water.

In the North Pacific there is only one range of seamounts between the Aleutian Islands and the Hawaiian Island chain that harbors bathyal species: the Emperor Seamount Chain. The North Pacific Intermediate Water crosses the chain at what is known as the Main Gap. This location will help the multidisciplinary team of scientists on Falkor identify this ecosystem transition. Up until now, most of the bathymetric surveys conducted in this area have been the result of transits, therefore lacking quality coverage necessary to pinpoint precise locations of study. This is why Falkor’s first task will be mapping the geologic features of the selected seamounts.

Proving the Currents

During their time on Falkor, the science team will combine a series of holistic experiments at six seamounts along the Emperor Chain to see if their suspicions are correct. Using currents, mapping, and radio isotopes to track water masses – as well as genetic sampling of corals – the team will determine the driving force behind coral distribution in this region. They may even find a new species of coral.

The soft-touch manipulator arms of Schmidt Ocean Institute’s ROV SuBastian will come in handy when picking up invertebrates and corals for imaging and genetic study. SuBastian will also be used to collect rock samples from the seamount, offering hidden clues of the past including circulation, chemistry, biology, geology, sedimentation and productivity. The team will use this information to reconstruct past environmental conditions going as far back as the last Glacial Maximum. This information will shed more light on the historical motives for the distribution and differentiation between the two biogeographic regions being examined.

 

In addition to the ROV work, Falkor’s CTD rosette will be used to identify an assorted mix of water masses that affect the types of organisms found at specific locations. Dr. Watling’s team believes that there are three water masses dominating the water column in the area with distinct geochemical signatures.

Seamounts are fascinating features of our oceans and taking a closer look at them is always extraordinary. Navigating the North Pacific while coming face to face with one of the most biodiverse ecosystems – corals – is sure to be a remarkable adventure.

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