A dead Central American coral reef tract: Possible link with the Little Ice Age

Abstract

Radiocarbon analyses, stable i'sotopic measurements and extensive field observations were made of coral reefs off the Pacific coast of Costa Rica and Panama, These analyses showed that live coral reefs in the Gulf of Papagayo, Costa Rica, were severely depleted in number, size and variety of species, compared to reefs in the major upwelling zone of the Gulf of Panama, Coral growth in the Gulf of Papagayo consisted mainly of dead reefs that died from 150-300 years B.P, The 0 18 0 records revealed that most of the dead reefs were exposed to relatively cool water immediately preceding death, We propose that during the latter part of the Little Ice Age there was probably an equatorward shift of the Northern Trade Wind system, which caused an intensification of upwelling at lower latitudes, This increased upwelling was the likely cause of the demise of coral reefs in the Gulf of Papagayo,

Demersal assemblages of the continental shelf and slope edge between the Gulf of Tehuantepec (Mexico) and the Gulf of Papagayo (Costa Rica)

“…Upwelling in the Gulf of Papagayo is also a well-known event. Temperatures below 20 "C have been observed in the surface waters near San Juan del Sur (Nicaragua), lasting about 3 mo (January to March; Glynn et al 1983). Hydrographic observations made with the RV 'Dr.…”

Variation of initial 230Th/232Th and limits of high precision U–Th dating of shallow-water corals

“…Difficulty arises when using these methods for precise absolute chronological control in the following cases: (1) living corals with banding discontinuities caused by climatic and/or tectonic anomalies (e.g., Sieh et al, 1999;Hendy et al, 2003;Natawidjaja et al, 2004), (2) corals living in the equatorial oceans with intrinsically small seasonal climatic cycles (as low as 0-2°C of seasonal temperature change), and (3) dead coral heads and fossils without absolute ages and/or mortality event-related age markers (Glynn et al, 1983;Yu et al, 2004).…”

Upwelling areas do not guarantee refuge for coral reefs in a warming ocean

“…Although these areas could constitute a refuge from bleaching, they have other features that could dampen reef development. For example, upwelling areas can be subjected to cold thermal stress (Glynn et al 1983), deep areas may host poorly connected reefs (Bongaerts et al 2010), and high flow can dislodge corals (Madin & Connolly 2006).…”