Polychaete dataset of the southwestern Gulf of Mexico including: taxonomic checklist, abundance, bathymetric distribution, functional diversity, geographic location, and sampling sites depth
Description
A taxonomic list of 69 genera belonging to 33 families of the Polychaeta class (Annelida) collected in 54 deepwater sites of the southwestern Gulf of Mexico is presented. Abundance data of these 69 genera is also included. A dataset of geographical location and depth of sampling sites
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The biological material was obtained along two cruises carried out on board the Oceanographic Vessel Justo Sierra of the National Autonomous University of Mexico. The samples were collected using a Reineck-type box corer with an effective area of 0.16 m2. A 0.08 m2 subsample was taken and washed on board through a 500-micrometer mesh sieve with previously filtered seawater. The result of this sieving was fixed with a mixture of seawater and 8 % formalin. In the laboratory, the extraction of the polychaetes specimens was carried out using an AVEN Mighty Vue Pro 5D ESD magnifying lamp (2.25X magnification). The specimens were separated using fine-tipped tweezers and placed in vials with 70% alcohol. Specimens was observed under a Zeiss Stemi 508 stereoscopic microscope (maximum magnification 50x). When it was necessary, the specimens (or a dissected portion) were mounted on a slide with a drop of a 70% alcohol-glycerol mixture and a coverslip and were observed with a Zeiss Primo Star optic microscope. General and specialized literature was used. Polychaetes identified at the genus level were collected at 38 sampling sites in SOGOM 1 and 46 in SOGOM 2. The abundance matrix was constructed adding the numbers recorded in both cruises. Thirty common sites in both cruises registered polychaetes identified at genus level. Twenty-four locations only presented polychaetes identified at genus level in one of the two cruises. This made a total of 54 sites with polychaetes identified at genus level. The sites were renamed in a scale order from one to 54 consecutively. The standardization of abundance (individuals per square meter) was done based on the number of each polychaete genus in each site. Four depth categories were determined according to the literature, and bathymetry of the Gulf of Mexico. These categories were: upper bathyal zone (185 -1000 m); middle bathyal zone (1001 -2000 m); lower bathyal zone (2001 -3000 m), and abyssal zone (3000 – 3760 m). The depth of each sampling site was recorded using the ship multibeam echosounder EM302, and the geographical location with the ship GPS at the time the corer got to the bottom. The site depth with an only fauna record in one of the two cruises was the one recorded in the data set of the sampling sites. An average depth was calculated for sites with data of the two cruises. Each of the 54 sites was assigned to one of the four established depth categories. The assignment of Polychaeta genera to the feeding guilds was carried out following the proposal of Jumars et al. (2015). The elaboration of the 100 % stacked bar graphs, was done based on the feeding guilds, and motility traits average and subsequently the percentage contribution of each biological trait to the depth categories. Based on this relative abundance matrix, the 100 % stacked bar graphs were generated using the STATISTICA 7 software.