QuERCi Update Seven

Niamh Connolly, 3rd Year, Earth Science, BSc, UCC

Keeping you posted on the progress of the RV Celtic Explorer! There has been exciting times recently on-board! Our run of incredible weather conditions continues which has greatly helped our data collection!

smlOn-deck viewUsing the multibeam echosounder data, Aaron Lim (PhD student) was skilfully able to create a detailed bathymetric map showing delicate features of the floor of the canyon in the Porcupine Bank. This allowed us to make a detailed dive plan for the enthusiastic biologists and geologists to watch this seafloor canyon come to life. The deepest point of the canyon reaches a water depth of just over 2,000m, while the ridges at the top are at approximately 700m. You can get an idea of the percipitous terrain.

 

Multibeam bathymetric map produced of the Porcupine Bank Canyon margin where coral mounds occur above a steep, sometimes vertical canyon walls (courtesy of Aaron Lim)

Multibeam bathymetric map produced of the Porcupine Bank Canyon margin where coral mounds occur above a steep, sometimes vertical canyon walls (courtesy of Aaron Lim)

Throughout this extensive dive, HD video footage and photographs were gathered as we wandered our way through the mysteries of this never before seen canyon floor.

Some crinoids and a small brittle star finding their home on a dropstone at the lower part of the Canyon channel

Some crinoids and a small brittle star finding their home on a dropstone at the lower part of the Canyon channel

We were interested to see what kind of life inhabited these areas and if the coral ecosystems and mounds we found earlier had also colonised the face of the cliff near the top of the Porcupine Bank Canyon. The deepest parts of the canyon were littered with sea pens and crinoids, much to the delight of our biologists on-board!

smlA crab, some black corals

A massive colony of black coral (Leiopathes sp.) attached to the hard surface of the cliff face

As for the cliff face of the canyon, with everyone glued to the live video feed, we were left amazed at the sheer extent and size of coral coverage found here! Massive coral colonies reaching out and thriving suggesting that they are taking advantage of the nutrients possibly upwelling from colder, deeper depths and carried by strong currents. A wonderful sight that couldn’t be missed!

Different species colonising the rock cliff face of the Canyon; Madrepora oculata (orange), Lophelia pertusa (whitish), black corals (red and orange [Leiopathes sp.]), black corals: Stichopathes sp. (yellow) and a few glass sponges (round and transparent-like in appearance)

Different species colonising the rock cliff face of the Canyon; Madrepora oculata (orange), Lophelia pertusa (whitish), black corals (red and orange [Leiopathes sp.]), black corals: Stichopathes sp. (yellow) and a few glass sponges (round and transparent-like in appearance)

smlA crab, some black corals

A crab, some black corals, dead and living Lophelia, Madrepora (white), black coral (orange), and bamboo coral (Paramuricea sp. [yellow]) covering the cliff face of the Porcupine Bank Canyon (what a sight!)

 

A crinoid sampled and preserved in ethanol

A crinoid sampled and preserved in ethanol

 

Deploying a gravity core to take sediment samples through a coral carbonate mound

Deploying a gravity core to take sediment samples through a coral carbonate mound

We have attempted to gather several gravity cores, but so far, unfortunately, they have been unsuccessful! However, we will continue to try and get sediment samples through the seabed near these intriguing cold-water coral mounds!

Our transit home will also begin shortly! Even though we are all excited to get home, our time spent in the Atlantic Ocean and the Porcupine Seabight has been an entertaining, insightful and thoroughly enjoyable experience, and at times almost too short! I hope to be back soon!

A massive thank you to Andy Wheeler, Aaron Lim and all the crew that made this cruise on the RV Celtic Explorer possible and such a great experience!!

Niamh Connolly, 3rd Year, Earth Science, Bsc, UCC.

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