Late Holocene Environmental Reconstruction of St. Michiel Saline Lagoon, Curaçao (Dutch Antilles)

Abstract

ABSTRACT. Two sediment cores collected from the saline lagoon St. Michiel on Curaçao (Dutch Antilles) preserve ã 5000-yr record of environmental change. Investigation of radiocarbon-dated sections by accelerator mass spectrometry (AMS) is based on faunal assemblage analyses, sediment mineralogy, and the interpretation of sedimentary facies. The cores recovered from different parts of the lagoon demonstrate different development. Initially, in the proximal part of the lagoon (core STM-2), the sediment accumulated in a coastal, semi-protected bay with strong marine influence, whereas the distal part (STM-1) was dominated by chemical precipitation (gypsum, aragonite). By about 3500-3400 BP, connection with the open sea became very limited due to the gradual formation of a coral rubble barrier at the coastline. Subsequently, the record reveals undisturbed sedimentation in the highly restricted shallow lagoon. Around 1100-1000 BP, biological and sedimentological records indicate a change to less evaporitic conditions. Stages of increased salinity are intercalated with intervals of episodic freshening due to increased runoff and precipitation. The authors demonstrate that since permanent human settlements were established on the island about 1100 BP, the watershed has undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century. Deforestation resulting from agriculture and construction caused increased erosion, which was translated to increased sediment accumulation rates and a shift in lagoon sedimentation from almost entirely endogenic to mostly detrital.

Shoreline changes and high-energy wave impacts at the leeward coast of Bonaire (Netherlands Antilles)

“…This is inferred from the subsequent layer of carbonate mud resembling recent deposition at KLB 1. High amounts of dolomite (>25%) within this lithofacies result from increasing Mg/Ca ratios due to evaporation of the supratidal sea water and withdrawal of Ca due to gypsum precipitation and secondary replacement of pre-existing CaCO 3 (Deffeyes et al, 1965;Klosowska et al, 2004). Subsequently, mangroves began to recolonise the site.…”

“…4). The evaporites relate to autochthonous sedimentation and a negative water balance due to limited water input either from the sea or inland in combination with high evaporation as also observed on Curaçao (Klosowska et al, 2004). Mg, Na, Cl and Ca ions indicate high evaporation rates and isolation from the sea similar to recent conditions, but also continuous sea water supply through the permeable seaward barrier.…”

“…according to Scheffers (2005) and Scheffers et al (2009). For the period when Saliña Tam closed (c. 3.5-3.4 ka BP), a gradual barrier formation was also reconstructed for the St. Michiel Lagoon at leeward Curaçao, which shares similar morphodynamic boundary conditions (Klosowska et al, 2004). However, the isolation of Saliña Tam is in the same time window as EWE I (inferred from the core at Klein Bonaire) which may have accumulated coral material at the outlet of the boka.…”

Checklist of the Birds of Aruba, Curaçao and Bonaire, South Caribbean

“…Versteeg & Ruiz (1995) give an account of the forests on Aruba. Since the arrival of Europeans, rapid growth of the population, felling of wood for private use and commerce, land cultivation and introduction of domestic animals have seriously affected the environment of the islands (Klosowska et al 2004), and have led to a serious decrease in the amount of forested land. Klosowska et al (2004), on the basis of sediment cores collected from Curaçao, demonstrate that since the establishment of permanent human settlements at around 1100 BP, watersheds have undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century (Terpstra 1948, Beers et al 1997.…”

“…Since the arrival of Europeans, rapid growth of the population, felling of wood for private use and commerce, land cultivation and introduction of domestic animals have seriously affected the environment of the islands (Klosowska et al 2004), and have led to a serious decrease in the amount of forested land. Klosowska et al (2004), on the basis of sediment cores collected from Curaçao, demonstrate that since the establishment of permanent human settlements at around 1100 BP, watersheds have undergone intensive deforestation, especially during the European colonization at the beginning of the 16th century (Terpstra 1948, Beers et al 1997. The presence of a high abundance of charred plant remains in two sediment cores dated at 900-1100 BP and 500 BP, respectively, representing land clearance by forest burning, indicates that land clearance by burning must have been a common practice by the newly arrived South American settlers.…”