Publications

deep-sea corals; paleoclimate; oxygen isotope; clumped isotope; boron isotope; SIMS; vital effect

Recent work demonstrates that bamboo coral growth temperature, averaged over its entire lifespan, can be derived from linear correlations in its carbon and oxygen isotope composition (δ13C, δ18O) when the apparent equilibrium fractionations for a coral's growth rate and calcifying pH are used. Building on this method, this study applies it to coeval coral skeleton to assess the possibility of extracting paleoceanographic timeseries from bamboo coral skeletons.

Deep-sea coral and sponge ecosystems are widespread throughout most of Alaska's marine waters, and are associated with many different species of fishes and invertebrates. These ecosystems are vulnerable to the effects of commercial fishing activities and climate change. We compared four commonly used species distribution models (general linear models, generalized additive models, boosted regression trees and random forest models) and an ensemble model to predict the presence or absence and abundance of six groups of benthic invertebrate taxa in the Gulf of Alaska.

Spatial management of vulnerable benthic ecosystem components such as deep-sea corals and sponges requires adequate maps of their distribution. These maps are often based on statistical models of survey data. The objective of this project was to validate the predictions of existing presence or absence and abundance models of deep-sea corals and sponges in the Aleutian Islands that were based on bottom trawl survey data.

In 2014, at the request of the Council, the National Marine Fisheries Service, Alaska Fisheries Science Center conducted a strip-transect survey along the Eastern Bering Sea slope to validate the results of a model predicting the occurrence of deep-sea coral habitat. More than 250,000 photos were analyzed to estimate coral, sponge, and sea whip abundance, distribution, height, and vulnerability to anthropogenic damage. The results of the survey confirmed that coral habitat and occurrence was concentrated around Pribilof Canyon and the adjacent slope. 

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Porifera, Suberitida, Suberitidae, Plicatellopsis, epibiontic on Hyas coarctatus, Halichondriidae, Spongosorites, Bering Sea, Alaska

Two new species, Plicatellopsis borealis and Spongosorites beringensis, from the Bering Sea are described; both belong to genera previously not reported from the area.

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Porifera, Trichogypsia alaskensis, new species, history of genus and family, Gulf of Alaska

A new species of Trichogypsiidae is described and compared to its congeners. Trichogypsia alaskensis n. sp. represents the fifth species of the family and with this record all three genera of the family are now represented in the North Pacific Ocean. Calcarea are rare in the Gulf of Alaska but with this new record the number of confirmed species rises from two to three. 

In the Mariana convergent margin, large arc volcanoes disappear south of Guam even though the Pacific plate continues to subduct and instead, small cones scatter on the seafloor. These small cones could form either due to decompression melting accompanying back-arc extension or flux melting, as expected for arc volcanoes, or as a result of both processes. Here, we report the major, trace, and volatile element compositions, as well as the oxidation state of Fe, in recently dredged, fresh pillow lavas from the Fina Nagu volcanic chain, an unusual alignment of small, closely spaced submarine calderas and cones southwest of Guam. 

As image-based identifications become a predominant method for deep-sea species characterizations, there is a need to evaluate the accuracy of species- and genus-level identifications from video and still images to provide a reliable measure of biodiversity. This study presents a validation of the ability to make accurate image-based identifications of black coral species in the northwestern Gulf of Mexico from standard-definition video collected by a remotely operated vehicle.

Benthic invertebrates; habitat; underwater survey; species distribution models; model validation; invertebrate size structure; density; Eastern Bering Sea; Alaska

Species distribution modeling is a useful tool for informing ecosystems management. However, validation of model predictions through independent surveys is rarely attempted in marine environments, which are challenging to study and often contain sensitive habitats. We conducted an underwater camera survey of the eastern Bering Sea slope and outer shelf as an independent test of species distribution modeling of deep-sea corals, sponges and sea whips based on bottom trawl survey data. 

Porifera; new demosponges; Gulf of Alaska; North Pacific Ocean

Two new species, Hamacantha (Vomerula) cassanoi n. sp. and Prosuberites salgadoi n. sp., are described from the eastern Gulf of Alaska in the North Pacific Ocean. These are the first records of the genera Hamacantha and Prosuberites from Alaska. We also report two geographic range extensions for the region.