Bivalve Diversity on the Continental Shelf and Deep Sea of the Perdido Fold Belt, Northwest Gulf of Mexico, Mexico

Abstract

Mollusk diversity in coastal areas of the Gulf of Mexico (GOM) has been studied extensively, but this is not the case for deep-water habitats. We present the first quantitative characterization of mollusks in shallow and deep waters of the Perdido Fold Belt. The data came from two research cruises completed in 2017. Sediment samples were collected from 56 sites using a 0.25-m2 box corer. We tested hypotheses about spatial patterns of α, β, and γ-diversity of bivalves in two water-depth zones, the continental shelf (43–200 m) and bathyal zone (375–3563 m). A total of 301 bivalves belonging to 39 species were identified. The two zones display similar levels of γ-diversity, but host different bivalve assemblages. In general, α-diversity was higher on the continental shelf, whereas β-diversity was higher in the bathyal zone. These patterns can be explained by the higher input of carbon (energy) to the near-coast shelf zone, as well as by the greater topographic complexity of habitats in the bathyal zone. These results enabled us to propose redirection of sampling efforts for environmental characterization from continental zones to the deep-water zone, especially in the context of environmental assessments during oil and gas exploration and production.

Ocean monitoring, observation network and modelling of the Gulf of Mexico by CIGOM

“…The development of a biological catalogue required the implementation of a wide variety of sampling and analysis techniques. Taxonomic and statistical analysis of samples collected during these oceanographic cruises allowed us to characterize the distribution and abundance patterns of phytoplankton (Linacre et al, 2019;Medina-Goḿez et al, 2019;Medina-Goḿez et al, 2020;Linacre et al, 2021;Ameńdola-Pimenta et al, 2021) fungi (Amend et al, 2019;Vargas-Gastélum et al, 2019), zooplankton (Hereu et al, 2021); ictyoplankton (Daudén-Bengoa et al, 2019;Daudén-Bengoa et al, 2020;Compaire et al, 2021;Santana-Cisneros et al, 2021a;Santana-Cisneros et al, 2021b), demersal fish communities in the water column (Vega Cendejas et al, 2017; Vega-Cendejas and De Santillana, 2019; Aguilar-Medrano and Vega-Cendejas, 2019a; Aguilar-Medrano and Vega-Cendejas, 2019b; Aguilar-Medrano and Vega-Cendejas, 2020b; Aguilar-Medrano and Vega-Cendejas, 2020a), benthic infauna, and invertebrates in the sediments (Hernańdez-Avila et al, 2018;Rubio et al, 2018;Aguilar-Medrano and Vega-Cendejas, 2020b;Torruco et al, 2018;Cisterna-Ceĺiz et al, 2019;Paz-Ríos and Pech, 2019;Hernández-Ávila et al, 2020;Martıńez-Aquino et al, 2020;Paz-Ríos et al, 2020;Soler-Jimenez et al, 2021;Paz-Rıós et al, 2021;Suaŕez-Mozo et al, 2021;Chí-Espínola and Vega-Cendejas, 2022;Quintanar-Retama et al, 2022). Methods for taxonomic identification ranged from the use of morphological techniques to massive sequencing of DNA molecules (metagenomics) and bioinformatic data analysis (Martínez-Aquino et al, 2017;Puch-Hau et al, 2018a;Escobar-Zepeda et al, 2018;Batta-Lona et al, 2019;…”