Dataset: Mariana Back-arc Macrofauna 2014
Deployment: RR1413

Deployment of Colonization Substrate
Two sets of three colonization "sandwiches" were deployed at Snail Vent, a hydrothermal vent in the Mariana Back-arc, during cruise YK10-11 in 2010. "Sandwiches" consisted of six Lexan plastic settlement plates, each measuring 0.7cm by 10cm by 10cm, separated from each other by 1cm spacers. The sandwich sets were placed near the base of a hydrothermal vent by the submersible Shinkai 6500. For additional deployment metadata, please refer to: http://www.marine-geo.org/tools/search/entry.php?id=YK10-11, in particular the Bottom:Deployed Event Marker-Sandwiches and Sampler:Biology:ColonizationSubstrate. We want to thank Chief Scientist Shigeaki Kojima for this sample deployment.

Recovery of Colonization Substrate
The sandwiches were left for approximately 4 years, and recovered by the ROV Jason II in 2014 on cruise RR1413. Only one set of colonization sandwiches was retrieved, as the other set was buried and could not be recovered. The maximum temperature observed at the sandwiches during recovery was 17.36 deg C. Sandwiches were initially placed into a biobox onboard the ROV, then transferred to another biobox on an elevator for recovery. During this transfer, as well as during the recovery of the elevator at the surface, some specimens may have been lost.

Shipboard Sample Processing
Sandwiches were removed from the biobox into individual bags and the elevator biobox washings were siphoned into a jar. The bags and jar were filled with ammonium sulfate solution buffered with EDTA and sodium citrate. We want to thank Shawn Arellano for this sample recovery and shipboard sample processing.

Laboratory Sorting and Morphological Identification
Samples remained in the ammonium sulfate solution for 1 to 1.5 years. Samples were rinsed with TE buffer prior to placement in 95% ethanol. The sandwiches were manually disassembled, and each entire plate- inclusive of both sides and edges- was examined for all attached macrofauna under a dissecting microscope at 25x. Washings were passed over a 63 micron sieve, and also examined at 25x.

Macrofauna, including foraminifera, were sorted to lowest taxonomic level, tallied, and placed into separate vials. Ciliates were tallied, but not usually retained; some were placed into sorted vials. Morphological identification was limited due to the degradation of the sample. We consulted with international experts to identify many of the morphotypes. All morphotypes, except the ciliates, were photographed. Potentially, ciliates could be identified through metabarcoding of the sorted vials. All photographs were by Mary Toner, with the exception of barnacles by Hiromi Watanabe.

This dataset is complete for one of the three "sandwiches", and for the biobox washings.

Genetic Barcoding
A subset of eight individuals, representing eight morphotypes, was prepared for the Canadian Centre for DNA Barcoding. We used sterile techniques to provide snips of larger specimens. The five submitted in 2017 used the CCDB regular protocol for extraction, amplification, (with two primer sets, C_LepFoIF/C_LepFOIR and ZplankF1/ZplankR1) and sequencing for the Cytochrome Oxidase Subunit 1 - 5 prime region (COI). The three submitted in 2018 used the CCDB protocol for Next Generation Sequencing for COI. Results may be viewed in the Barcode of Life Data System (BOLD) Public Data Portal using the project search SNLBE. We also consulted with international experts on genetic sequences.

Problem Report
One set of colonization "sandwiches" could not be recovered, as it was buried by a partial collapse of surrounding rock.

Some specimens may have been lost during a transfer of samples between bioboxes at the seafloor, as well as upon recovery at the surface. As such, our counts cannot be used for quantitative analysis of hydrothermal macrofauna.