A 6000-year record of ecological and hydrological changes from Laguna de la Leche, north coastal Cuba

摘要

Laguna de la Leche, north coastal Cuba, is a shallow (<= 3 m), oligohaline (similar to 2.0-4.5 parts per thousand) coastal lake surrounded by mangroves and cattail stands. A 227-cm core was studied using loss-on-ignition, pollen, calcareous microfossils, and plant macrofossils. From similar to 6200 to similar to 4800 cal yr BP, the area was an oligohaline lake. The period from similar to 4800 to similar to 4200 cal yr BP saw higher water levels and a freshened system; these changes are indicated by an increase in the regional pollen rain, as well as by the presence of charophyte oogonia and an increase in freshwater gastropods (Hydrobiidae). By similar to 4000 cal yr BP, an open mesohaline lagoon had formed; an increase in salt-tolerant foraminifers suggests that water level increase was driven by relative sea level rise. The initiation of Laguna de In Leche Correlates with a shift to wetter conditions as indicated in pollen records from the southeastern United States (e.g., Lake Tulane). This synchronicity suggests that sea level rise caused middle Holocene environmental change region-wide. Two other cores sampled from mangrove swamps in the vicinity of Laguna de la Leche indicate that a major expansion of mangroves was underway by similar to 1700 cal yr BP. (c) 2006 University of Washington. All rights reserved.