Patterns of Deep-Water Coral Diversity in the Caribbean Basin and Adjacent Southern Waters: An Approach based on Records from the R/V Pillsbury Expeditions

Abstract

The diversity of deep-water corals in the Caribbean Sea was studied using records from oceanographic expeditions performed by the R/V Pillsbury. Sampled stations were sorted according to broad depth ranges and ecoregions and were analyzed in terms of species accumulation curves, variance in the species composition and contributions to alpha, beta and gamma diversity. According to the analysis of species accumulation curves using the Chao2 estimator, more diversity occurs on the continental slope (200–2000 m depth) than on the upper continental shelf (60–200 m depth). In addition to the effect of depth sampling, differences in species composition related to depth ranges were detected. However, the differences between ecoregions are dependent on depth ranges, there were fewer differences among ecoregions on the continental slope than on the upper continental shelf. Indicator species for distinctness of ecoregions were, in general, Alcyonaria and Antipatharia for the upper continental shelf, but also the scleractinians Madracis myriabilis and Cladocora debilis. In the continental slope, the alcyonarian Placogorgia and the scleractinians Stephanocyathus and Fungiacyathus were important for the distinction of ecoregions. Beta diversity was the most important component of gamma diversity in the Caribbean Basin. The contribution of ecoregions to alpha, beta and gamma diversity differed with depth range. On the upper continental shelf, the Southern Caribbean ecoregion contributed substantially to all components of diversity. In contrast, the northern ecoregions contributed substantially to the diversity of the Continental Slope. Strategies for the conservation of deep-water coral diversity in the Caribbean Basin must consider the variation between ecoregions and depth ranges.

Variation in species diversity of deep-water megafauna assemblages in the Caribbean across depth and ecoregions

“…Data were sorted according to major deep-sea zones and ecoregions. The major depth zones include: 1) the shelf, the mesophotic-aphotic realm, 60–200 m depth, close to coastal habitats, and relatively connected with shallow-water systems; 2) the slope, following the shelf, at 200–2000 m depth, aphotic, very close to the coast depending on their profile, and variable coastal influence; 3) the rise, open-sea stations, at 2000–4000 m depth, on the border of the Caribbean continental margin, includes the depth of the Aragonite saturation horizon in the Atlantic (approximately 2500 m deep [ 44 ]); 4) the abyssal, internal plains at Caribbean sub-basins, 4000–6000 m deep, and 5) the hadal (> 6000 m, restricted to the Puerto Rico trench)[ 31 , 45 ]. The biogeographical subdivisions follow Spalding et al [ 33 ] and includes 1) the Greater Antilles (59 Stations), 2) Eastern Caribbean (45 Stations), 3) Western Caribbean (21 Stations), 4) Southern Caribbean (53 Stations), 5) Southwestern Caribbean (79 Stations) and 6) the Guianian Ecoregion (21 Stations).…”

“…Evidence of diversity patterns as a function of depth, including clues in the Caribbean Basin, are based on the estimation of species ranges [ 3 , 29 ], which could generate a spurious unimodal model [ 30 ]. For the Caribbean Basin, sample-based estimations of diversity applied to deep-water corals have revealed more diversity at the continental slope than on the shelf [ 31 ] but species richness in deeper habitats is uncertain. The changes in diversity with depth could also be caused by turnover in species composition, species loss promoted by ecological filters associated with depth, or a combination of both processes [ 25 , 32 ].…”

“…Nevertheless, there is evidence suggesting regional variation among the abyssal fauna in the Caribbean (3411–5062 m deep)[ 34 ], for deep-water scleractinian corals (> 50 m deep)[ 3 , 35 ] and in diverse groups of corals on the continental shelf and slope [ 31 ]. Additionally, the spatial variation in species composition of deep-sea corals changes between the continental shelf and the slope [ 31 ].…”

Cold Seeps Associated with Structured Benthic Communities: More Accurate Identification and Evaluation Using a New Multibeam Survey Methodology in the Offshore Southern Colombian Caribbean

“…There are three sites with deep-water corals between 70 m and 150 m depth identified in the Colombian Caribbean [6]; other corals were found corals in the same area at between 120 m and 180 m depth [15]. Deeper surveys have also been carried out, analyzing 210 stations in 8 sectors of the Colombian Caribbean between 10 m and 510 m deep, finding a diversity of deep-water corals [16], and deep-water corals were also studied in the Greater Caribbean area with more than 204 stations and a depth range between 60 and 5400 m depth [17]; their stations with deep water corals in the south Caribbean, most representative species were present no deeper than 480 m. The baseline studies performed on Gran Fuerte as a requirement for the environmental licenses showed no presence of deep-water corals in any of the box corer samples in the Gran Fuerte area as well [18]. However, the analysis of the 2006 survey did show two shallow (400 -800 m) ridges of hard substrate that is relatively near to a priority conservation site where deep-water corals were already reported (Figure 9).…”

OCCURRENCE OF THE BRACHIOPODTICHOSINAIN DEEP-SEA CORAL BOTTOMS OF THE CARIBBEAN SEA AND ITS PALEOENVIRONMENTAL IMPLICATIONS

“…These field surveys resulted in the recognition of a deep-water coral structure called San Bernardo Bank (Lutz and Ginsburg, 2007), as well as others coral-dominated habitats (see Reyes et al, 2005, Santodomingo et al, 2007, Santodomingo et al, 2013 in the Caribbean continental shelf of Colombia. Then, we used a dataset on the benthic macrofauna from the R/V Pillsbury sampling program (1966 to 1972), including corals, mollusks and echinoderms, assembled from databases of the Natural Museum of Natural History, Smithsonian Institution and the Marine Invertebrate Museum, Rosenstiel School of Marine and Atmospheric Science (MIN-RSMAS) (Hernández-Ávila, 2014). Brachiopod data from the R/V Pillsbury sampling program were gathered from an extensive monograph on modern Caribbean brachiopods elaborated by Cooper (1977).…”