Overview of VI MCE systems

The eastern Puerto Rican Shelf (PRS) (i.e., from Vieques and Culebra eastward including St. Thomas, St. John and the British Virgin Islands) supports an extensive mesophotic coral ecosystem that is a central component of regional biodiversity. Deeper coral reefs in this context include Mesophotic Coral Ecosystems (MCE) that form at depths between 30 – 100 m in the Caribbean. Only recently have systematic investigations of MCE been conducted at any scale and most MCE habitats are poorly described in pattern and process. These MCE habitats of the eastern PRS cover an area similar to shallow water coral reefs and are a critical component of regional fisheries, including grouper and snapper spawning aggregations. This area is primarily divided into northern shelf, of which very little is known, and a southern shelf (SPRS), that is only just beginning to be described to science, management, and society. Few areas have been adequately characterized in terms of geology, ecology, or diversity (e.g., there are only patchy MCE habitat maps), and high-resolution bathymetry of the southern shelf was only completed as recently as 2011. Targeted research and numerous observations over the past ten years have shown that the SPRS is composed of distinct MCE habitats, with heterogeneous structures and principal habitat forming species (Nemeth et al. 2008; Smith et al. 2010). Perhaps the most dynamic and important of these MCE is the upper shelf edge, a primary bank of 30-70m depth. This bathymetric feature likely represents a drowned Pleistocene barrier reef on the southern shelf, while the precedence of the northern shelf is unknown. The shelf edge is a transitional zone between neritic and pelagic ecosystems and from shelf top to outer slope and wall benthic MCE. In addition, the shelf edge harbors important natural resources, such as grouper and snapper spawning aggregations and antipatharian (black coral) populations.

Relevant References

Eyal G, Wiedenmann J, Grinblat M, D’Angelo C, Kramarsky-Winter E, Treibitz T, Ben-Zvi O, Shaked Y, Smith TB, Harii S, Denis V (in press) Coral fluorescence in a mesophotic reef habitat. PLoS ONE

Smith TB, Maté JL, Gyory J (in press) Refuges and refugia for stony corals in the eastern tropical Pacific. Invited book chapter for “Coral Reefs of the World: Coral Reef of the Eastern Tropical Pacific” Glynn PW, Manzello D, Enochs, I (eds.) Springer- Verlag

Serrano A, Baums I, O’Reilly K, Smith TB, Jones R, Shearer T, Flavia N, Baker A (2014) Geographic differences in vertical connectivity in the Caribbean coral Montastraea cavernosa despite high levels of horizontal connectivity at shallow depths. Molecular Ecology 23:4226–4240

Smith TB, Glynn PW, Mate JL, Toth LT, Gyory J (2014) A depth refuge from catastrophic coral bleaching prevents regional extinction. Ecology 95:1663-1673

Weinstein DK, Smith TB, Klaus JS (2014) Mesophotic bioerosion: structural impact and changes with depth on US Virgin Island deep reefs. Geomorphology 222:14-24

Gleason ACR, Lirman D, Gintert B, Dick M, Reid RP, Gracias N, Smith TB (2010) Landscape video mosaic from a mesophotic coral ecosystem. Coral Reefs 29:253

Smith TB, Blondeau J, Nemeth RS, Pittman, SJ, Calnan JM, Kadison E, Gass J (2010) Benthic structure and cryptic mortality in a Caribbean mesophotic coral reef bank system, the Hind Bank Marine Conservation District, U.S. Virgin Islands. Coral Reefs 29:289-308

Calnan J, Smith TB, Nemeth R, Kadison E, Blondeau J (2008) Coral disease prevalence and host susceptibility on mid-depth and deep reefs in the US Virgin Islands. Revista Biologia Tropical 56:223-234

Smith TB, Nemeth RS, Blondeau J, Calnan J, Kadison E, Herzlieb S (2008) Assessing coral reef health across onshore to offshore stress gradients in the US Virgin Islands. Marine Pollution Bulletin. 56:1983-1991