scholarly journals Absence of Saharan dust influence on the strontium isotope ratios on modern trees from the Bahamas and Turks and Caicos Islands

2018 ◽  
Vol 89 (2) ◽  
pp. 394-412 ◽  
Author(s):  
Rick Schulting ◽  
Mike Richards ◽  
John Pouncett ◽  
Bryan Naqqi Manco ◽  
Ethan Freid ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Saharan Dust ◽  
Soil Types ◽  
Sr Isotope ◽  
The Bahamas ◽  
Turks And Caicos Islands ◽  
Order Of Magnitude ◽  
The Caribbean ◽  
The Impact ◽  
Bahamian Archipelago

AbstractWe report on strontium (87Sr/86Sr) isotope results from 91 modern trees growing on the Bahamas and Turks and Caicos Islands. The average87Sr/86Sr ratio of 0.709169±0.000010 is consistent with the late Quaternary limestone of the islands and with the modern ocean value. The absence of any detectable influence of87Sr-enriched Saharan dust is notable, given the known contribution of this material to both past and recent soils of the Caribbean. Our results indicate that the impact of Saharan dust to the modern biosphere of the Bahamian archipelago is at least an order of magnitude less than modeled in currently available strontium isoscapes for the circum-Caribbean. We suggest that the bioavailability of Sr in Saharan dust may be considerably less than previously thought. Nevertheless, further work could usefully be carried out in the Bahamian archipelago on plants with different rooting depths, growing on different soil types and on limestone of different ages. Our results have particular relevance for the refinement of existing strontium isoscapes and the archaeological provenience of artifacts, animals, and people in the circum-Caribbean.

scholarly journals Absence of Saharan dust influence on the strontium isotope ratios on modern trees from the Bahamas and Turks and Caicos Islands – ERRATUM

2018 ◽  
Vol 90 (1) ◽  
pp. 251-251 ◽  
Author(s):  
Rick Schulting ◽  
Mike Richards ◽  
John Pouncett ◽  
Bryan Naqqi Manco ◽  
Ethan Freid ◽  
...  
Keyword(s):  
Isotope Ratios ◽  
Strontium Isotope ◽  
Saharan Dust ◽  
The Bahamas ◽  
Turks And Caicos Islands ◽  
Strontium Isotope Ratios

scholarly journals The influence of Holocene vegetation changes on topography and erosion rates: A case study at Walnut Gulch Experimental Watershed, Arizona

2016 ◽  
Author(s):  
Jon D. Pelletier ◽  
Mary H. Nichols ◽  
Mark A. Nearing
Keyword(s):  
Vegetation Change ◽  
Late Quaternary ◽  
Drainage Density ◽  
Vegetation Changes ◽  
Arid Environments ◽  
Decadal Time Scale ◽  
Erosion Rates ◽  
Order Of Magnitude ◽  
Walnut Gulch ◽  
The Impact

Abstract. Quantifying how landscapes have responded and will respond to vegetation changes is an essential goal of geomorphology. The Walnut Gulch Experimental Watershed offers a unique opportunity to quantify the impact of vegetation changes on landscape evolution over geologic time scales. The Walnut Gulch Experimental Watershed (WGEW) is dominated by grasslands at high elevations and shrublands at low elevations. Paleovegetation data suggest that portions of WGEW higher than approximately 1430 m a.s.l. have been grasslands and/or woodlands throughout the late Quaternary, while elevations lower than 1430 m a.s.l. changed from a grassland/woodland to a shrubland c. 2–4 ka. Elevations below 1430 m a.s.l. have decadal time-scale erosion rates approximately ten times higher, drainage densities approximately three times higher, and hillslope-scale relief approximately three times lower than elevations above 1430 m. We leverage the abundant geomorphic data collected at WGEW over the past several decades to calibrate a mathematical model that predicts the equilibrium drainage density in shrublands and grasslands/woodlands at WGEW. We use this model to test the hypothesis that the difference in drainage density between the shrublands and grassland/woodlands at WGEW is partly the result of a late Holocene vegetation change in the lower elevations of WGEW, using the upper elevations as a control. Model predictions for the increase in drainage density associated with the shift from grasslands/woodlands to shrublands are consistent with measured values. Using modern erosion rates and the magnitude of relief reduction associated with the transition from grasslands/woodlands to shrublands, we estimate the timing of the grassland-to-shrubland transition in the lower elevations of WGEW to be approximately 3 ka, i.e., broadly consistent with paleovegetation studies. Our results provide support for the hypothesis that common vegetation changes in semi-arid environments (e.g. from grassland to shrubland) can change erosion rates by more than an order of magnitude, with important consequences for landscape morphology.

scholarly journals The influence of Holocene vegetation changes on topography and erosion rates: a case study at Walnut Gulch Experimental Watershed, Arizona

2016 ◽  
Vol 4 (2) ◽  
pp. 471-488 ◽  
Author(s):  
Jon D. Pelletier ◽  
Mary H. Nichols ◽  
Mark A. Nearing
Keyword(s):  
Vegetation Change ◽  
Late Quaternary ◽  
Drainage Density ◽  
Vegetation Changes ◽  
Arid Environments ◽  
Erosion Rates ◽  
Order Of Magnitude ◽  
The Difference ◽  
Walnut Gulch ◽  
The Impact

Abstract. Quantifying how landscapes have responded and will respond to vegetation changes is an essential goal of geomorphology. The Walnut Gulch Experimental Watershed (WGEW) offers a unique opportunity to quantify the impact of vegetation changes on landscape evolution over geologic timescales. The WGEW is dominated by grasslands at high elevations and shrublands at low elevations. Paleovegetation data suggest that portions of WGEW higher than approximately 1430 m a.s.l. have been grasslands and/or woodlands throughout the late Quaternary, while elevations lower than 1430 m a.s.l. changed from a grassland/woodland to a shrubland ca. 2–4 ka. Elevations below 1430 m a.s.l. have decadal timescale erosion rates approximately 10 times higher, drainage densities approximately 3 times higher, and hillslope-scale relief approximately 3 times lower than elevations above 1430 m. We leverage the abundant geomorphic data collected at WGEW over the past several decades to calibrate a mathematical model that predicts the equilibrium drainage density in shrublands and grasslands/woodlands at WGEW. We use this model to test the hypothesis that the difference in drainage density between the shrublands and grassland/woodlands at WGEW is partly the result of a late Holocene vegetation change in the lower elevations of WGEW, using the upper elevations as a control. Model predictions for the increase in drainage density associated with the shift from grasslands/woodlands to shrublands are consistent with measured values. Using modern erosion rates and the magnitude of relief reduction associated with the transition from grasslands/woodlands to shrublands, we estimate the timing of the grassland-to-shrubland transition in the lower elevations of WGEW to be approximately 3 ka, i.e., broadly consistent with paleovegetation studies. Our results provide support for the hypothesis that common vegetation changes in semi-arid environments (e.g., from grassland to shrubland) can change erosion rates by more than an order of magnitude, with important consequences for landscape morphology.

scholarly journals Megafauna decline have reduced pathogen dispersal which may have increased emergent infectious diseases

2020 ◽  
Author(s):  
Christopher E. Doughty ◽  
Tomos Prys-Jones ◽  
Søren Faurby ◽  
Andrew Abraham ◽  
Crystal Hepp ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Human Populations ◽  
Home Ranges ◽  
Mammal Species ◽  
Fold Reduction ◽  
Theory Of Island Biogeography ◽  
Order Of Magnitude ◽  
Fecal Pathogens ◽  
Dispersal Distances ◽  
The Impact

AbstractThe Late Quaternary extinctions of megafauna (defined as animal species >44.5 kg) reduced the dispersal of seeds and nutrients, and likely also microbes and parasites. Here we use body-mass based scaling and range maps for extinct and extant mammal species to show that these extinctions led to an almost seven-fold reduction in the movement of gut-transported microbes, such as Escherichia coli (3.3 km2/day to 0.5 km2/day). Similarly, the extinctions led to a seven-fold reduction in the mean home ranges of vector-borne pathogens (7.8 km2 to 1.1 km2). To understand the impact of this, we created an individual-based model where an order of magnitude decrease in home range increased maximum aggregated microbial mutations 4-fold after 20,000 years. We hypothesize that pathogen speciation and hence endemism increased with isolation, as global dispersal distances decreased through a mechanism similar to the theory of island biogeography. To investigate if such an effect could be found, we analysed where 145 zoonotic diseases have emerged in human populations and found quantitative estimates of reduced dispersal of ectoparasites and fecal pathogens significantly improved our ability to predict the locations of outbreaks (increasing variance explained by 8%). There are limitations to this analysis which we discuss in detail, but if further studies support these results, they broadly suggest that reduced pathogen dispersal following megafauna extinctions may have increased the emergence of zoonotic pathogens moving into human populations.

scholarly journals The paleoecology and extinction of endemic tortoises in the Bahamian Archipelago

The Holocene ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 420-427
Author(s):  
David W Steadman ◽  
Nancy A Albury ◽  
Lizabeth A Carlson ◽  
Richard Franz ◽  
Michelle J LeFebvre ◽  
...  
Keyword(s):  
Native Species ◽  
Late Holocene ◽  
Human Settlement ◽  
The Bahamas ◽  
Turks And Caicos Islands ◽  
Human Contact ◽  
Accelerator Mass Spectrometer ◽  
Island Group ◽  
Bahamian Archipelago ◽  
Archeological Site

No native species of tortoises ( Chelonoidis spp.) live today in the Bahamian (Lucayan) Archipelago (= The Bahamas + The Turks and Caicos Islands), although a number of species inhabited these islands at the first human contact in the late-Holocene. Until their extinction, tortoises were the largest terrestrial herbivores in the island group. We report 16 accelerator mass spectrometer (AMS) radiocarbon (14C) dates determined directly on individual bones of indigenous, extinct tortoises from the six Bahamian islands (Abaco, Eleuthera, Flamingo Cay, Crooked, Middle Caicos, Grand Turk) on five different carbonate banks. These 16 specimens probably represent six or seven species of tortoises, although only one ( Chelonoidis alburyorum on Abaco) has been described thus far. Tortoises seem to have survived on most Bahamian islands for only one or two centuries after initial human settlement, which took place no earlier than AD ~700–1000. The exception is Grand Turk, where we have evidence from the Coralie archeological site that tortoises survived for approximately three centuries after human arrival, based on stratigraphically associated 14C dates from both tortoise bones and wood charcoal. The stable isotope values of carbon (σ13C) and nitrogen (σ15N) of dated tortoise fossils show a NW-to-SE trend in the archipelago that may reflect increasing aridity and more consumption of cactus.

African Bermudian English and the Caribbean connection

2013 ◽  
Vol 34 (3) ◽  
pp. 279-304 ◽  
Author(s):  
Nicole Eberle ◽  
Daniel Schreier
Keyword(s):  
Settlement Patterns ◽  
The Bahamas ◽  
Population Demographics ◽  
Turks And Caicos Islands ◽  
Phonological Features ◽  
The World ◽  
Transfer Pattern ◽  
The Caribbean ◽  
Similarities And Differences

Bermudian English (BerE) is one of the least documented varieties of English that has undergone full nativisation. The only source we are aware of is Ayres (1933), who provides an overview of some selected phonological features. The present paper has two aims: first, to provide a preliminary morphosyntactic profile of African Bermudian English (ABerE) and to anchor this variety in the quickly emerging canon of lesser-known varieties of English around the world (Schreier et al. 2010), and second, to gain some first typological insights whether or not it aligns with English in the Caribbean (and if so, with which varieties), as has been claimed by some sources (e.g. Trudgill 2002). With this aim, we report some first findings from a fieldwork study on the island and in a later step compare these with selected Caribbean varieties — Bahamian English (BahE), Bajan, Jamaican English, and Vincentian Creole, as reported in the Electronic World Atlas of Varieties of English (Kortmann and Lunkenheimer 2011). We argue that morphosyntactic similarities and differences between the varieties are explained by the Bermudian community’s sociohistorical and sociolinguistic contexts, including settlement patterns, population demographics, and peopling, and that the emergence and origins of a stable localised variety of (A)BerE need to be approached with reference to the historical connections between Bermuda and the communities that provided donor varieties. We further argue in favor of a two-way transfer pattern: Caribbean Englishes are likely to have influenced the evolution of English on Bermuda, while BerE itself was an influential input variety in other locations (particularly the Bahamas and the Turks and Caicos Islands).

scholarly journals Optimization of viral resuspension methods for carbon-rich soils along a permafrost thaw gradient

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1999 ◽  
Author(s):  
Gareth Trubl ◽  
Natalie Solonenko ◽  
Lauren Chittick ◽  
Sergei A. Solonenko ◽  
Virginia I. Rich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Storage Conditions ◽  
Potassium Citrate ◽  
Soil Types ◽  
Citrate Buffer ◽  
Permafrost Thaw ◽  
C Cycling ◽  
Permafrost Soils ◽  
Order Of Magnitude ◽  
The Impact

Permafrost stores approximately 50% of global soil carbon (C) in a frozen form; it is thawing rapidly under climate change, and little is known about viral communities in these soils or their roles in C cycling. In permafrost soils, microorganisms contribute significantly to C cycling, and characterizing them has recently been shown to improve prediction of ecosystem function. In other ecosystems, viruses have broad ecosystem and community impacts ranging from host cell mortality and organic matter cycling to horizontal gene transfer and reprogramming of core microbial metabolisms. Here we developed an optimized protocol to extract viruses from three types of high organic-matter peatland soils across a permafrost thaw gradient (palsa, moss-dominated bog, and sedge-dominated fen). Three separate experiments were used to evaluate the impact of chemical buffers, physical dispersion, storage conditions, and concentration and purification methods on viral yields. The most successful protocol, amended potassium citrate buffer with bead-beating or vortexing and BSA, yielded on average as much as 2-fold more virus-like particles (VLPs) g−1of soil than other methods tested. All method combinations yielded VLPs g−1of soil on the 108order of magnitude across all three soil types. The different storage and concentration methods did not yield significantly more VLPs g−1of soil among the soil types. This research provides much-needed guidelines for resuspending viruses from soils, specifically carbon-rich soils, paving the way for incorporating viruses into soil ecology studies.

Pound Wise and Penny Foolish? Weight Loss and The Dynamics of Health Care Spending

2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch
Keyword(s):  
Weight Loss ◽  
Cost Savings ◽  
Cost Effective ◽  
Economic Consequences ◽  
Health Care Spending ◽  
Order Of Magnitude ◽  
Dynamic Measures ◽  
The Cost ◽  
The Impact ◽  
The Relationship

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.

scholarly journals Processes, Challenges and Optimisation of Rum Production from Molasses—A Contemporary Review

Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 21
Author(s):  
Tinashe Mangwanda ◽  
Joel B. Johnson ◽  
Janice S. Mani ◽  
Steve Jackson ◽  
Shaneel Chandra ◽  
...  
Keyword(s):  
Management Practices ◽  
Scientific Literature ◽  
Asia Pacific ◽  
Yeast Strains ◽  
Challenges And Opportunities ◽  
The Caribbean ◽  
The Impact ◽  
Production Industry ◽  
Stringent Quality

The rum industry is currently worth USD 16 billion, with production concentrated in tropical countries of the Caribbean and Asia-Pacific regions. The primary feedstock for rum production is sugar cane molasses, a by-product of sugar refineries. The main variables known to affect rum quality include the composition of the molasses, the length of fermentation, and the type of barrels and length of time used for aging the rum. The goal of this review is to provide an overview of the impact of these variables on rum quality, and to highlight current challenges and opportunities in the production of rum from molasses. In order to achieve this, we review the relevant contemporary scientific literature on these topics. The major contemporary challenges in the rum production industry include minimising the effects of variability in feedstock quality, ensuring the fermentation process runs to completion, preventing microbial contamination, and the selection and maintenance of yeast strains providing optimum ethanol production. Stringent quality management practices are required to ensure consistency in the quality and organoleptic properties of the rum from batch to batch. Further research is required to fully understand the influences of many of these variables on the final quality of the rum produced.

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