Fauna diversity in Madracis spp. coral patches in the Colombian Caribbean

Study Extent

The CPNNP is located in the Colombian Caribbean (fig. 1) on the continental margin off the Gulf of Morrosquillo and the Archipelago of San Bernardo, approximately 12 km from one of the areas with major development of shallow-water coral reefs in Colombia, Corales del Rosario y de San Bernardo National Natural Park, and 32 km from the nearest point on the continent (Barú Peninsula). The area is characterized by a strong influence of continental inputs, relatively transparent waters, and large mosaics combining bio-clastic sediment plains and extensive development of coral reefs (Díaz et al., 2000).

Sampling

The work circumscribed biodiversity data where Madracis coral patches occur southwest of the CPNNP, at depths of 107 and 230 m. These patches are located within the coordinates 9° 46' 18.208" N - 9° 50' 33.101" N and 76° 11' 10.099'' W - 76° 14' 39.688'' W (fig. 1). Madracis colonies have been identified as a species complex that includes M. myriaster (the most abundant), M. asperula and M. brueggemanni (Santodomingo et al., 2007) (fig. 2) given the difficulty to differentiate M. myriaster from its sister species M. brueggemanni (Ballesteros-Contreras et al., 2022). According to the digital elevation model (DEM), they are on a moderate slope between 4º to 11º in the transition between the continental shelf and the shelf-break scarp, probably covered by recent sediment flows, and over a sliding crown (Santodomingo et al., 2007; Morales et al., 2017). Biodiversity data were compiled from four research expeditions carried out in the southwest area of the CPNNP (table 1): (1) “Macrofauna II” (2001), a baseline survey on soft bottoms in the Colombian Caribbean with collections made with an epibenthic trawl net (9 × 1 m opening; 3 knots for 10 min) (fig. 3A) (Reyes et al., 2005). (2) “Marcoral'' expedition (2005), a study for mapping and characterizing the occurrence of Madracis corals using a single-beam echo sounder, collections with a Van Veen dredge (60 l, 0.03 m2) (fig. 3B) and a heavy-chained rocky dredge (1 × 0.4 m opening; 1.5 knots for 5 min) (Santodomingo et al., 2007; Santodomingo et al., 2013). (3) “PNN Corales Profundidad'' expedition (2015), to perform detailed geomorphological mapping (Morales et al., 2017) supported by the first footage obtained using ROV Diavolo II (fig. 3C) with a front camera (¼′′ CCD 380 I TV-lines, 0.1 Lux/F = 1.2) and 10 cm parallel lasers for scale. Positioning was estimated using an ultra-short baseline (USBL) mounted on the vehicle (Cedeño-Posso et al., 2002). (4) “PNN Madracis” expedition (2016), a complementary expedition for sampling areas using a multipurpose drift-cam (CADEM) with a modified Van Veen grab (0.066 m2) to collect samples of sediments (fig. 3D). The drift-cam incorporates high-definition cameras capable of acquiring color images with 61° range, 120x zoom and 2200 lumen LED lights, both with titanium casing resistant up to 4000 m depth, a multimedia tracking console, and adaptable protection cages for different environments.

Quality Control

The quality of the videos (380 TV-lines) allowed recognition only of common taxa larger than 10 cm (cnidarians, crustaceans, echinoderms and fish), with exceptional cases of fauna > 5-10 cm such as cup corals with extended polyps and crustaceans. Biological samples that remained unsorted from Marcoral and PNN Madracis (Bryozoa and Annelida) were identified to the lowest taxonomic level possible. Identifications were confirmed from videos based on specimens deposited in the collections of the Museo de Historia Natural Marina de Colombia (MHNMC) – Makuriwa of INVEMAR in Santa Marta, Colombia. Data quality controls were applied to the species previously identified in “Macrofauna II” and Marcoral campaigns through the validation of their current taxonomic status. Likewise, taxonomic levels higher than family were excluded from the analysis to avoid uncertain identifications and data duplicity, except for specimens identified in the orders Antipatharia, Comatulida and Ophiurida that correspond to unique specimens observed in the ROV videos. Consulted updated taxonomic identities and classifications in the World Register of Marine Species (WoRMS, 2022) and Eschmeyer´s Catalog of Fishes (Fricke et al., 2020). All biological data and collections are available in SiBM and it stored voucher specimens at the Makuriwa Museum. Our analyses use the concept of species diversity in terms of species/morphospecies richness. Geo references for stations were verified by the Geographic Information Systems Laboratory of INVEMAR (LabSiG) through ArcGIS Desktop - ArcMap 10.6 (2018) Software.

Method steps

1. Coordinates and sampling methods for the 14 stations analyzed in this review are summarized in table 1.

1. Cnidaria
   rank: phylum
2. Anthozoa
   rank: class
3. Hydrozoa
   rank: class
4. Bryozoa
   rank: phylum
5. Stenolaemata
   rank: class
6. Gymnolaemata
   rank: class
7. Brachiopoda
   rank: phylum
8. Rhynchonellata
   rank: class
9. Annelida
   rank: phylum
10. Clitellata
    rank: class
11. Polychaeta
    rank: class
12. Mollusca
    rank: phylum
13. Bivalvia
    rank: class
14. Gastropoda
    rank: class
15. Arthropoda
    rank: phylum
16. Malacostraca
    rank: class
17. Echinodermata
    rank: phylum
18. Crinoidea
    rank: class
19. Ophiuroidea
    rank: class
20. Asteroidea
    rank: class
21. Echinoidea
    rank: class
22. Chordata
    rank: phylum
23. Actinopterygii
    rank: class

The CPNNP is located in the Colombian Caribbean (fig. 1) on the continental margin off the Gulf of Morrosquillo and the Archipelago of San Bernardo, approximately 12 km from one of the areas with major development of shallow-water coral reefs in Colombia, Corales del Rosario y de San Bernardo National Natural Park, and 32 km from the nearest point on the continent (Barú Peninsula). The area is characterized by a strong influence of continental inputs, relatively transparent waters, and large mosaics combining bio-clastic sediment plains and extensive development of coral reefs (Díaz et al., 2000).