Research papers Shoreline foraminiferal thanatacoenoses around five eastern Caribbean islands and their environmental and biogeographic implications Brent Wilson a,n , Jacqueline I. Wilson b a Petroleum Geoscience Programme, Department of Chemical Engineering, University of the West Indies, St. Augustine, Trinidad, West Indies b Centre for Medical Sciences Education, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad, West Indies article info Article history: Received 3 December 2010 Received in revised form 3 February 2011 Accepted 13 February 2011 Available online 21 February 2011 Keywords: Amphistegina gibbosa St. John USVI Hurricanes Guyana current Organic matter enrichment abstract Foraminiferal thanatacoenoses were examined around five islands in the Caribbean Sea, which forms a single biogeographic province with respect to nearshore ( o3 m water depth) foraminifera, which live primarily on marine vegetation. On death, they become incorporated into the sediment. The assemblage at a site reflects the live assemblage and post mortem affects such as dissolution and transport during storms. Reefal species (Amphistegina gibbosa, Asterigerina carinata) are transported towards shore during storms. Foraminiferal thanatacoenoses were examined in 65 nearshore sediment samples from around five eastern Caribbean islands: St. John (US Virgin Islands), St. Kitts, Nevis, Bequia and Tobago. Cluster and principal components analyses distinguished the following environments (indicator species in parentheses): 1. Sediment associated with mangroves (Ammonia sobrina), 2. Bays subject to organic matter enrichment (Quinqueloculina poeyana, Triloculina rotunda, T. trigonula), 3. Areas subject to moderate sediment flux during storms (Quinqueloculina auberiana, Nodobaculariella mexicana, Peneroplis proteus, Archaias angulatus), 4. Locations subject to high sediment flux during storms (Amphistegina gibbosa), 5. Sites little stressed by organic matter enrichment or storms (Discorbis rosea). The majority of samples were from sites in the last category. The data from this study could form the nucleus of a catalogue of Caribbean beaches and their environmental influences. & 2011 Elsevier Ltd. All rights reserved. 1. Introduction The Foraminifera is a class of small (usually o1 mm) amoeboid protists with reticulating rhizopods that produce a chambered test (shell) that can be preserved after death. They construct their tests either by agglutinating sediment particles or secreting calcium carbonate, and abound in all marine environments. They are par- ticularly diverse in tropical reefal environments (Murray, 2006) such as those in the Caribbean Sea, which is bordered to the north and east by islands that are encircled by coral reefs but separated by more or less deep water (Fig. 1). The nearshore ( o3 m water depth) benthonic foraminifera around these islands were first studied by d’Orbigny (1839) and have since been reported in 4100 papers (Culver and Buzas, 1982). Within these nearshore areas they live primarily on marine vegetation (Cushman, 1922; Steinker and Clem, 1984). Although Martin and Wright (1988) concluded that much ecological information is lost when they die and their tests become incorporated into the sediment, much useful information remains. Thus, Seiglie (1971) was able to use sediment assemblages to detect pollution by organic matter in some Caribbean bays. Given that foraminiferal tests vary in shape and size and so react differently to hydrodynamic forces (Martin and Liddell, 1991), sediment assem- blages have the potential to indicate which beaches on different islands are subject to organic pollution or similar hydrodynamic conditions. This has implications for land use planning. Although the channels separating the islands of the eastern Caribbean potentially act as barriers to dispersal to nearshore organisms, Culver and Buzas (1982) concluded on the basis of species presence–absence that many foraminiferal species are ubiquitous within the region. However, the vectors of percentage abundances of species forming the thanatacoenoses within the sediment vary at smaller, intra-island scales. Brasier (1975) qualitatively discerned several distinct communities around Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/csr Continental Shelf Research 0278-4343/$ - see front matter & 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.csr.2011.02.010 n Corresponding author. Tel.: +1 868 662 2002x3676. E-mail addresses: brent.wilson@sta.uwi.edu (B. Wilson), jacqui.wilson@sta.uwi.edu (J.I. Wilson). Continental Shelf Research 31 (2011) 857–866