Bahamas Research Articles

Stromatolite-thrombolite associations in a modern environment, Lee Stocking Island, Bahamas

Columnar buildups found in a tidal channel off Lee Stocking Island, Exuma Cays, Bahamas, have been interpreted as modern giant stromatolites growing in a subtidal normal marine environment. However, these organically-formed columns reveal three discernible internal structures: (1) prokaryotic stromatolites comprised of alternating layers of coarse-grained ooids and peloids, and fine micrite that formed exclusively by microbial activity; (2) eukaryotic stromatolites comprised of microbially-induced micritic layers alternating with detrital layers accumulated, bound, and cemented by eukaryotic algae; and (3) thrombolites displaying irregular, clotted fabrics and formed by microbes, algae, and metazoans. Phanerozoic thrombolites, in contrast, have been interpreted as unlaminated stromatolites constructed by cyanobacteria. Eukaryotic organisms overgrow all of the columns at present. Thus, the contemporaneous formation of prokaryotic stromatolites, eukaryotic stromatolites, and thrombolites under identical conditions within the present environment appears unlikely. We suggest that the prokaryotic stromatolites represent forms that began to develop in an intertidal setting with the Holocene flooding of the Great Bahama Bank. The thrombolites, however, began to form under the present, normal-marine subtidal conditions. The eukaryotic stromatolites represent intermediate forms between prokaryotic stromatolites and thrombolites. There is evidence for a gradual change from stromatolite to thrombolite reefs associated with rising sea-level. With the deepening, there would have been a decrease in salinity, an increase in energy, and possibly an increase in nutrient supply; all factors that favor thrombolite growth. We propose that the co-existing stromatolites and thrombolites found off Lee Stocking Island did not grow contemporaneously, but reflect a response to changing environmental controls with changing sea-level.

Climatic Control of Hydraulic Conductivity of Bahamian Limestones

AbstractData from 244 single‐well pumping tests of the karstified Lucayan Limestone on 14 different islands distributed through the Bahamian Archipelago, demonstrate a strong log‐linear relationship between annual rainfall and the effective mean island effective hydraulic conductivity, which averages over two orders of magnitude higher in the wetter northern Bahamas (mean anual rainfall 1550 mm) than in the more arid southern islands (mean annual rainfall 810 mm). This relationship is independent of the saturated depth of the boreholes tested, although the hydraulic conductivity of the lower part of the formation is significantly greater (about 0.6–0.7 order of magnitude) than the upper unit, reflecting progressive secondary porosity generation with time.The direct effect of increasing ground‐water flux on rates of dissolutional porosity generation in the wetter northern islands is supplemented by the greater geochemical potential for carbonate dissolution resulting from higher primary vegetative production. This both increases soil pCO2 via root respiration (a process augmented by higher soil moisture permitting more microbial activity), and the availability of organic matter for in situ oxidation within the aquifer. Effective hydraulic conductivity may also be directly related to island size. Islands in the north of the Archipelago are larger than those in the south, thus the fresh‐water lens and fresh‐/ salt‐water mixing zone are greater in size and expose more bedrock to dissolution.

Flora of the Bahama Archipelago (Including the Turks and Caicos Islands)

Flora of the Bahama Archipelago (Including the Turks and Caicos Islands)

Cayman Islands: Anti Money‐Laundering Legislation — The Proceeds of Criminal Conduct Law 1996

‘Q. Why the Caymans? You could have gone anywhere. You had a lot of money. You could have gone to Paris, the Bahamas?

Characteristics of HIV-infected pregnant women in the Bahamas.

The Commonwealth of the Bahamas has one of the highest rates of acquired immunodeficiency syndrome (AIDS) in the English-speaking Caribbean. A seroprevalence study of pregnant women attending antenatal clinics in New Providence in 1990-91 showed that of 3,914 pregnant women tested, 2.9% were human immunodeficiency virus (HIV) infected. Women born in the Bahamas constituted 79.2% of the women tested; 17.7% were born in Haiti. The rate of HIV infection was 2.5% in the Bahamian women as compared with 4.5% in those born in Haiti. The highest incidence was in women aged 25-34 years and in women who had multiple pregnancies. There was a significant association with a history of crack cocaine use by the Bahamian women. There was also a significant association between a lack of education and HIV infection in this group. There was a lower rate of condom use among women with less education and also among women in common-law relationships, but the association of lack of condom use and HIV infection did not reach statistical significance.

The Genus Ernodea (Rubiaceae) in the Caribbean Basin. II. Morphological Analyses and Systematics

The genus Ernodea, consisting of erect or prostrate shrubs, has been thought to consist of nine species, most of which are endemic to the Bahamian Archipelago. The classification of the genus is difficult because the original species descriptions are incomplete and include characters of great plasticity. Addition- ally, reproductive and genetic studies failed to provide evidence to support recognition of distinct species. We measured 30 floral and vegetative characters from samples representing all taxa and distributed across the entire range of the genus to delimit relationships at the specific level and to delineate morphological gaps within the genus. Phenetic analyses involving Principal Component Analysis and Canonical Discriminant Analysis provided consistent separation of two main clusters; each cluster separated into two subclusters. Vegetative characters provided better discrimination than floral characters. In contrast to the current literature, this study recognizes four morphological species: E. cokeri, E. littoralis, E. taylori and E. millspaughii. The morphological and ecological diversity of Ernodea in these islands suggest that there has been rapid divergence associated with adaptive radiation. A key to the species with descriptions and nomenclature is provided.

The Genus Ernodea (Rubiaceae) in the Caribbean Basin. I. Allozyme Variation and Mating Systems

Ernodea consists of nine historically recognized species, most of which are endemic to the Bahamian Archipelago. The species are quite diverse morphologically, and their boundaries are difficult to identify because of intermediate forms. As part of a comprehensive investigation of the evolution and taxonomy of the genus, populations of five of the taxa were studied on Great Abaco and Great Inagua (Bahamas) and Puerto Rico. Starch gel electrophoresis was performed on leaf extracts and 13 scorable loci were examined. The five species studied were fixed for the same allele across 12 of these loci. The one variable locus showed variation that appears to be more highly correlated with geography rather than morphology. These data provide no evidence of genetic barriers among the species. Hand-pollination experiments tested for apomixis, selfing, outcrossing, and inter-specific fertility. These experiments suggested that there are no reproductive barriers between the species and that the species have a mixed-mating system. The data accumulated in this study do not support, but neither can they refute, the recognition of nine distinctive taxa in this genus.

Microsatellite Libraries Enriched for Several Microsatellite Sequences in Plants

Microsatellite Libraries Enriched for Several Microsatellite Sequences in Plants

Late Holocene climate change and human disturbance on Andros Island, Bahamas

A 2 m sediment core from Church's Blue Hole on Andros Island, Bahamas provides the first paleoecological record from the Bahama Archipelago. The timing of events in the lower portion of the core is uncertain due to inconsistencies in the radiocarbon chronology, but there is evidence that a late Holocene dry period altered the limnology of Church's Blue Hole and supported only dry shrubland around the site. The dry period on Andros may correlate with a widespread dry period in the Caribbean from 3200 to 1500 yr BP. After the dry period ended, a more mesic climate supported tropical hardwood thicket around Church's Blue Hole. At c. 740 radiocarbon yr BP there is a sudden rise in charcoal concentration and a rapid transition to pinewoods vegetation, while at c. 430 radiocarbon yr BP charcoal concentration drops, but is higher again near the top of the core. Although climatic shifts could have caused these changes in vegetation and charcoal concentration, the changes post-date human colonization of the Bahamas and may reflect human arrival, followed by the removal of humans c. 1530 AD and the recolonization of Andros Island c. 200 years later.

First Records of the Shiny Cowbird (Molothrus bonariensis) in the Bahama Archipelago

The spread of the Shiny Cowbird (Molothrus bonariensis) northward through the Caribbean during the past 93 years has been well documented (Post and Wiley 1977, Cruz et al. 1985). The species reached mainland Puerto Rico in 1955 (Grayce 1957), the Dominican Republic in 1973 (Bond 1973), and Cuba in 1982 (Garrido 1984). It first appeared in North America in 1985 (Paul 1985) and since then has been recorded in several states, including Florida, Georgia, Louisiana, North Carolina, South Carolina, Oklahoma, Texas, and Maine (Post et al. 1993). Although the islands of the Bahama Archipelago would appear to have been ideal stepping stones for the Shiny Cowbird from the Caribbean to North America, the species was not detected during extensive surveys of the region (Connor and Loftin 1985, Buden 1987a, b, c, 1990, 1992a, b, Dewey 1989, Norton and Clarke 1989, Baltz 1993; R. L. Norton, reports of Christmas Bird Counts in the Bahamas 1985-1993 in American Birds). I describe observations of Shiny Cowbirds on North Andros Island that are the first records of the species in the Bahama Archipelago.

Pre-Sangamonian eolianites in the Bahamas? New evidence from Eleuthera Island

The present study provides new insight into the Quaternary stratigraphy of the Bahamas. Refining the stratigraphic record of tectonically stable carbonate islands, such as the Bahamas, is important for improving our perception of eustatic and climatic variations during this time interval. Two key-sections located 15 km apart in the northern portion of Eleuthera display three vertically stacked rock-units: (1) a basal unit consisting of up to four eolianites separated by paleosols, (2) intermediate oolitic deposits showing beach facies at +6 m, and (3) an upper bioclastic eolianite overlain by a thick calcrete. The occurrence of beach facies at an elevation of 6 m above MSL suggests an Early Sangamonian age (isotopic substage 5e) for the intermediate oolitic deposits. Because of its position below a thick calcrete, the upper unit was more likely formed during a later highstand of the Sangamonian (substage 5c or 5a), rather than during the Holocene. It follows that the basal unit clearly predates the last interglacial. This new evidence from Eleuthera shows that pre-Sangamonian rocks may be more extensive in the Bahamas Archipelago than previously thought. It also emphasizes the widespread occurrence of bioclastic limestones in an area often considered as being entirely composed of oolites.

The colonization of the Bahama archipelago: A reappraisal

Abstract A number of colonization models have been proposed to explain the prehistoric peopling of the Bahamas archipelago from the Greater Antilles. Each varies in respect to place of origin, timing of migration and settlement, routes of movement, intentionality, settlement permanency and causal agents. The paper summarizes the evidence for each of the models. A new model which suggests that late Ostionan Ostionoid people from northern Cuba colonized the central Bahama archipelago circa ad 600–900 is presented. This model incorporates the articulation of palaeoclimatic push factors, economic pull factors, ease of transport factors and shallow bank navigation.

Quaternary tectonic stability of the Bahamian archipelago: evidence from fossil coral reefs and flank margin caves

Throughout the islands of the Bahamian archipelago fossil coral reefs are found from current sea level up to a maximum elevation of +4 m. 234 U 230 Th radiometric dates obtained from in situ corals from these reefs, by both alpha-count and mass-spectrometric techniques, indicates that they were all formed during Oxygen Isotope Substage 5e (ca. 125,000 years ago). Those data are consistent with a maximum sea-level highstand of +6 m during Substage 5e, and either no vertical motion of the Bahamas, or possible isostatic subsidence of up to 2 m during the past 120,000 years. No older in situ fossil corals, or other subtidal deposits, have been found subaerially exposed anywhere in the Bahamas. That finding suggests that late Quaternary (at least the past 300,000 years) isostatic subsidence has occurred at a rate of 1–2 m per hundred thousand years, and/or no pre-5e highstands were above modern sea level. An independent corroboration of the conclusions drawn about sea level amplitude and tectonic stability of the Bahamas from the coral reef data is available from examination of abundant flank margin caves (horizontal, phreatic dissolution caves) found above modern sea level throughout the Bahamas. These horizontally extensive air-filled caves have dissolutional ceilings with elevations that are restricted to +1 to +7 m, which is consistent with formation at the margin of a thin freshwater lens elevated by a past +6 m sea-level highstand. The restricted cave elevations, and the lack of stalagmites in these caves that are older than 100,000 years, are also consistent with cave formation during Substage 5e, and possible subsequent isostatic subsidence of a few metres. The subsurface geology of the southeastern Bahamas contains a long-term record (millions of years) that has been attributed to past tectonic activity along the North American/Caribbean plate boundary. While that record suggests differential subsidence across the Bahamas in the Tertiary Period, the data from fossil coral reefs (and subtidal deposits) and flank margin caves indicate that all Bahamian banks on which there are islands have been tectonically stable, and behaving similarly, for at least the past several hundred thousand years.

Fishes of the Bahamas and Adjacent Tropical Waters.James E. Bohlke , Charles C. G. Chaplin

<i>Fishes of the Bahamas and Adjacent Tropical Waters.</i>James E. Bohlke , Charles C. G. Chaplin

The people who discovered Columbus: the prehistory of the Bahamas

The people who discovered Columbus: the prehistory of the Bahamas

Lobsters: Florida, Bahamas, the Caribbean

Lobsters: Florida, Bahamas, the Caribbean

Weissia (Hymenostomum) flavescens New to the United States

Weissia (Hymenostomum) flavescens (E. G. Britt. in N. L. Britt. & Millsp.) Reese is reported new to the United States on three specimens from Big Pine Key, in the Florida Keys. It occurs on the nearby island ofGrand Bahama and elsewhere in the Bahamian archipelago, Bermuda, Puerto Rico, and the Virgin Islands. My recent study (Reese 1991) of specimens of Weissia (Hymenostomum) flavescens (E. G. Britt. in N. L. Britt. & Millsp.) Reese from Grand Bahama Island, which lies approximately 100 km east of southern Florida, prompted me to look again at some of my earlier collections from the Florida Keys. This revealed a single specimen of W. flavescens (previously determined as W. viridula Hedw.). Two other specimens named W. viridula from the Florida Keys (NY) also turned out to be W. flavescens, which is here reported new to the United States. FLORIDA. MONROE CO.: BIG PINE KEY: 4 mi. N of US 1 on soil in interior of hammock, McDaniel 5837 (rNY); Rockland Pine Forest, on limestone and soil, Redfearn 3069 (NY); on soil at base of pine tree, Reese 1284 [DUKE (microscope slide), LAF]. The plants of these three collections are indistinguishable from those of the Bahamian populations that I have studied. The McDaniel specimen is a mixture of W. flavescens and an unidentified Weissia-like species with large, pellucid, more or less smooth leaf cells, involute leaf margins, and welldeveloped Weissia-like peristome, which also appears to be new to the United States. Plants of Weissia subg. Hymenostomum resemble those of peristomate Weissia in all respects, including involute leaf margins, except that the sporophyte lacks a peristome. Some authors, e.g., Crosby and Magill (1981) and Wijk et al. (1969), recognize Hymenostomum at the generic level but others, e.g., Crum and Anderson (1981), Noguchi (1988), Saito (1975), Smith (1978), and Stoneburner (1985), include Hymenostomum in Weissia (sometimes as a subgenus). Thus the modem tendency is to discount the eperistomate condition as an indicator of generic rank. Gametophytically, W. flavescens differs from W. controversa in having its leaf margins generally erect except toward the leaf tip, where the margins are usually involute as in W. controversa. Restriction of involution of the margins to the upper part of the leaf gives the leaves a cucullate appearance. The leaves of dry plants of W. flavescens are variously contorted but not curled as in typical W. controv-

Junkanoo in the Bahamas

Junkanoo in the Bahamas

The Orchidaceae of the Bahama Archipelago: Additions, Distributional Extensions, and Nomenclatural Change

This paper reports the results of our continuing investigation of the Orchidaceae of the Bahama Archipelago. Included are the addition to the orchid flora of a species not previously reported,Harrisella filiformis (Sw.) Cogn.; descriptions of four natural hybrids,Encyclia × guzinskii, Encyclia × hillyerorum, Encyclia × knowlesii, andTolumnia × adamsii, heretofore unknown; five distributional extensions; and the reinstatement of the nameEncyclia altissima Schltr.

Aristida correlliae, a New Species of Poaceae from the Turks and Caicos Islands

A new species, Aristida correlliae (Poaceae: Aristida sect. Chaetaria) is described and illustrated from South Caicos Island and Long Cay in the Bahama Archipelago, where it grows on stony open ground as an uncommon member of a diverse, arid, scrub community. The new species is similar to A. refracta and A. calcicola in certain habit and leaf features, but differs from these taxa in culm, spikelet, and leaf blade and sheath apex pubescence characters. Aristida correlliae is like A. lanosa and A. stricta in certain pubescence features but exhibits a different habit and a smaller inflorescence. A key is provided for all species of the Bahama Archipelago. During our recent investigation of the aris- tidas of Puerto Rico and the Virgin Islands, we attempted to clarify the range of A. cognata Trin. & Rupr. in the West Indies (McKenzie et al. 1989). We discovered that numerous specimens that formed the basis for the report of A. cognata in the Bahamas actually are A. adscensionis L. Misidentifications of A. adscensionis apparently result because keys stress the usually annual habit of this species. We agree with McVaugh (1983) that the annual habit of A. adscensionis may be difficult or impossible to determine from herbarium material, especially in the case of large plants... . Some specimens of A. ad- scensionis that we have examined would be bet- ter described as short-lived perennials and not annuals. Kelly Allred (pers. comm., New Mex- ico State University-NMCR) observed the same characteristic for many specimens of A. adscen- sionis from western North America. Specimens of A. adscensionis that resemble perennials would key to A. cognata in some manuals.