Seasonal distribution patterns of juvenile loggerhead sea turtles (<Emphasis Type="Italic">Caretta caretta</Emphasis>) following capture from a shipping channel in the Northwest Atlantic Ocean

Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel (32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground.     

Aesthetascs in Lysmata spp. shrimp: sexual dimorphism and relationship with social environments

Aesthetascs are the olfactory receptor organs responsible for mate recognition in many decapod crustacean species. The number of aesthetascs varies greatly among species in different environments, but the functional significance of this variation is poorly understood. This study examined the relationship between social environment and the number of aesthetascs in six species of caridean shrimp in the genus Lysmata. Generally, the number of aesthetascs was greater in group-living species (L. boggessi and L. wurdemanni) than in low-density (L. ankeri and L. pederseni) and pair-living species (L. amboinensis and L. debelius). Aesthetascs are innervated by olfactory receptor neurons (ORNs). The total number of ORNs is related to the sensitivity of olfactory odor detection, and it was higher in group-living species than in pair-living species. Sexual dimorphism in the number of aesthetascs was present in L. boggessi, L. wurdemanni, and L. ankeri but not in L. pederseni and L. amboinensis.     

Seasonal patterns in fatty acids of <Emphasis Type="Italic">Calanus hyperboreus</Emphasis> (Copepoda,Calanoida) from Cumberland Sound,Baffin Island,Nunavut

The marine copepod Calanus hyperboreus accumulates large quantities of lipids and essential fatty acids during summer months in Northern oceans. However, few data exist regarding their winter fatty acid profiles, which could be informative regarding the use of lipids by C. hyperboreus to successfully survive and reproduce during times of ice-cover and limited food. The present study compared fatty acids of C. hyperboreus between summer (August 2007 and 2008) and winter (early April 2008 and 2009) in Cumberland Sound, Canada. Summer samples from both years had significantly higher ∑polyunsaturated fatty acids and unsaturation indices (based on μg fatty acid mg dry tissue⁻¹) than winter samples and separated on a principal component analysis due to higher 18:2n-6, 18:4n-3, and 20:5n-3, consistent with phytoplankton consumption. Winter C. hyperboreus had significantly higher ∑monounsaturated fatty acids (MUFA) versus summer samples and separated on the principal component analysis due to higher proportions of 16:1n-7, 20:1n-9, and 22:1n-9, suggesting they were not actively feeding. Based on the seasonal fatty acid comparison, C. hyperboreus was catabolizing specific fatty acids (e.g. 20:5n-3), conserving others (e.g. 22:6n-3), and maintaining or increasing biosynthesis of certain MUFA (e.g. 18:1n-9) during winter. These findings provide insight into the seasonal strategy of acquisition (summer) and utilization (winter) of specific fatty acids by a key Arctic organism and could become important for monitoring changes in fatty acids associated with decreased ice-cover duration due to climate warming.     

On the shoals of giants: natural catastrophes and the overall destruction of the Caribbean’s archaeological record

In this paper I review a host of natural and cultural processes that have affected the preservation and integrity of archaeological sites on islands in the West Indies, many of which are located in low-lying coastal areas. Given the position of the Caribbean lithospheric plate—juxtaposed between four others—it is no surprise that by its very nature the region is volcanically active and frequently associated with earthquake and tsunami events. This makes coastal zones, and related archaeological sites in the region, highly susceptible to a wide range of destructive natural events. The high frequency of tropical systems (hurricanes and storms) in the Caribbean and rising sea level, coupled with human activities such as sand mining, development, and looting, makes the region’s archaeological record one of the most vulnerable and threatened in the world. Ongoing research is dedicated to understanding how past populations may have been affected by these events in the past.     

Trade‐Offs between Cattle Production and Bird Conservation in an Agricultural Frontier of the Gran Chaco of Argentina

Intensification of food production in tropical landscapes in the absence of land‐use planning can pose a major threat to biological diversity. Decisions on whether to spatially integrate or segregate lands for production and conservation depend in part on the functional relations between biological diversity and agricultural productivity. We measured diversity, density, and species composition of birds along a gradient of production intensification on an agricultural frontier of the Argentine Chaco, where dry tropical forests are cleared for cattle production. Bird species diversity in intact forests was higher than in any type of cattle‐production system. Bird species richness decreased nonlinearly as cattle yield increased. Intermediate‐intensity silvopastoral systems, those in which forest understory is selectively cleared to grow pastures of non‐native plants beneath the tree canopy, produced 80% of the mean cattle yield obtained in pastures on cleared areas and were occupied by 70–90% of the number of bird species present in the nearest forest fragments. Densities of >50% of bird species were significantly lower in open pastures than in silvopastoral systems. Therefore, intermediate‐intensity silvopastoral systems may have the greatest potential to sustain cattle yield and conserve a large percentage of bird species. However, compared with low‐intensity production systems, in which forest structure and extent were intact, intermediate‐intensity silvopastoral systems supported significantly fewer forest‐restricted bird species and fewer frugivorous birds. These data suggest that the integration of production and conservation through intermediate‐intensity silvopastoral systems combined with the protection of forest fragments may be required to maintain cattle yield, bird diversity, and conservation of forest‐restricted species in this agricultural frontier. Compromisos entre la Producción de Ganado y la Conservación de Aves en una Frontera Agrícola del Gran Chaco de Argentina     

Application of multicriteria choice-methods in assessing eutrophication

Multicriteria choice-methods, often used in policy analysis, were examined as a methodological procedure for eutrophication assessment. Multicriteria analysis ranked the sampling sites along two coastal areas, according to nutrient and chlorophyll concentrations. Three levels of nutrient loading were revealed, characterizing eutrophic, mesotrophic and oligotrophic waters. These results have been compared to station grouping based on multivariate analysis which indicated similar trends. Multicriteria choice-methods were shown to be an effective methodological tool in assessing eutrophication. In addition, this approach is compatible with multicriteria methods applied on policy-making and therefore the problem of eutrophication can be integrated with plan and project evaluation in environmental management.     

The efficacy of a limestone doser to mitigate stream acidification in a Maryland coastal plain stream: Implications for migratory fish species

The objective of this two-year study was to determine the efficacy of an automated limestone slurry doser to neutralize acidic pulses and improve water quality conditions for enhancing survival of early life stages of migratory fish species in a Maryland coastal plain stream. Implications for survival of early life stages of migratory fish species such as yellow perch (Perca flavescens), white perch (Morone americana), blueback herring (Alosa aestivalis) and alewife (Alosa pseudoharengus) are discussed based on the improved chemical conditions in the dosed area of the stream. Despite problems with overdosing in 1991 and failure of the stage transducer to work properly in 1992, the doser was generally effective in neutralizing acidic pulses (pH depressions) in the stream during three major rain events in both years. Chemical conditions (pH and inorganic monomeric aluminum) reported in the non-dosed area during major rainfall events were potentially stressful to both alewife and blueback herring although neither species was reported spawning in the stream during either year. Mitigating the potential impact of acidic conditions on early life stages of important migratory fish species was not sufficient to ensure spawning. It is therefore recommended that habitat improvement measures and well designed fish stocking programs be implemented concurrently with doser operations if the goal is to create optimum spawning conditions for migratory species.     

A comparison of X-ray fluorescence and wet chemical analysis of air filter samples from a scrap lead smelting operation

Personal and area air samples were taken at a scrap lead smelter operation in a bullet manufacturing facility. Samples were taken using the 37-mm styrene-acrylonitrile closed-face filter cassette (CFC, the current US standard device for lead sampling), the 37-mm GSP or "cone" sampler, the 25-mm Institute of Occupational Medicine (IOM) inhalable sampler, and the 25-mm Button sampler (developed at the University of Cincinnati). Polyvinylchloride filters were used for sampling. The filters were pre- and post-weighed, and analyzed for lead content using a field-portable X-ray fluorescence (XRF) analyzer. The filters were then extracted with dilute nitric acid in an ultrasonic extraction bath and the solutions were analyzed by inductively coupled plasma optical emission spectroscopy. The 25-mm filters were analyzed using a single XRF reading, while three readings on different parts of the filter were taken from the 37-mm filters. The single reading from the 25-mm filters was adjusted for the nominal area of the filter to obtain the mass loading, while the three readings from the 37-mm filters were inserted into two different algorithms for calculating the mass loadings, and the algorithms were compared. The IOM sampler was designed for material collected in the body of the sampler to be part of the collected sample as well as that on the filter. Therefore, the IOM sampler cassettes were rinsed separately to determine if wall-loss corrections were necessary. All four samplers gave very good correlations between the two analytical methods above the limit of detection of the XRF procedure. The limit of detection for the 25-mm filters (5 microg) was lower than for the 37-mm filters (10 microg). The percentage of XRF results that were within 25% of the corresponding ICP results was evaluated. In addition, the bias from linear regression was estimated. Linear regression for the Button sampler and the IOM sampler using single readings and the GSP using all tested techniques for total filter loading gave acceptable XRF readings at loadings equivalent to sampling at the OSHA 8-hour Action Level and Permissible Exposure Limit. However, the CFC only had acceptable results when the center reading corrected for filter area was used, which was surprising, and may be a result of a limited data set. In addition to linear regression, simple estimation of bias indicated reasonable agreements between XRF and ICP results for single XRF readings on the Button sampler filters, (82% of the individual results within criterion), and on the IOM sampler filters (77% or 61%--see text), and on the GSP sampler filters using the OSHA algorithm (78%). As a result of this pilot project, all three samplers were considered suitable for inclusion in further field research studies.     

Natural and anthropogenic enrichments of molybdenum, thorium, and uranium in a complete peat bog profile, Jura Mountains, Switzerland

A core from an ombrotrophic Swiss bog representing 12 370 (14)C years of peat accumulation was evaluated as a possible archive of atmospheric deposition of Mo, Th and U. Calcium, Sr, and Ba were also determined to quantify weathering inputs, Mn to follow possible redox transformations, and Rb to identify plant uptake. Each of these elements was determined using ICP-MS, following digestion in a microwave heated autoclave using 3 ml HNO(3) and 0.1 ml HBF(4). Calcium and Sr clearly identify the thickness of the ombrotrophic zone because they are enriched in the minerogenic zone relative to the concentration of mineral matter. The concentration of Ba, however, is proportional to the concentration of mineral matter in all samples, and is not added to peat column by weathering reactions at the peat-sediment interface. The lowest element concentrations are found during the Holocene climate optimum (5320 to 8030 (14)C year BP) with the following natural background values (n= 18): Mo 0.08 +/- 0.02 microg g(-1), U 0.029 +/- 0.008 microg g(-1), Ba 5.2 +/- 2.6 microg g(-1), Th 0.070 +/- 0.022 microg g(-1) and Rb 0.63 +/- 0.09 microg g(-1). By far the highest concentrations of Ba, Mn, Rb and Th were found during the Younger Dryas cold climate event (10 590 (14)C year BP) when the flux of atmospheric soil dust was at its post-glacial maximum. Molybdenum and U are elevated in concentration throughout the minerogenic zone because of sediment weathering and this masks the atmospheric signal in samples older than ca. 8000 (14)C year BP (ca. 9000 calendar years). Enrichment factors (EF) calculated using Sc as a conservative, lithogenic element shows that minerogenic peats are enriched in Mo up to 18x and U 26x, relative to the natural "background" values. During the two millennia prior to industrialisation, the accumulation rate of atmospheric Mo averaged 0.23 +/- 0.13 microg m(-2) year(-1). With the onset of the Industrial Revolution, Mo accumulation rates rapidly and continuously increased to approximately 10 microg m(-2) year(-1) in the late 1980s. These data suggest that Mo in atmospheric aerosols today is derived predominately from anthropogenic emissions. Uranium does not show the same enrichment pattern which suggests that steel-making rather than coal combustion is the primary source of atmospheric Mo contamination at this site.     

Suggested protocol for collecting, handling and preparing peat cores and peat samples for physical, chemical, mineralogical and isotopic analyses

For detailed reconstructions of atmospheric metal deposition using peat cores from bogs, a comprehensive protocol for working with peat cores is proposed. The first step is to locate and determine suitable sampling sites in accordance with the principal goal of the study, the period of time of interest and the precision required. Using the state of the art procedures and field equipment, peat cores are collected in such a way as to provide high quality records for paleoenvironmental study. Pertinent field observations gathered during the fieldwork are recorded in a field report. Cores are kept frozen at -18 degree C until they can be prepared in the laboratory. Frozen peat cores are precisely cut into 1 cm slices using a stainless steel band saw with stainless steel blades. The outside edges of each slice are removed using a titanium knife to avoid any possible contamination which might have occurred during the sampling and handling stage. Each slice is split, with one-half kept frozen for future studies (archived), and the other half further subdivided for physical, chemical, and mineralogical analyses. Physical parameters such as ash and water contents, the bulk density and the degree of decomposition of the peat are determined using established methods. A subsample is dried overnight at 105 degree C in a drying oven and milled in a centrifugal mill with titanium sieve. Prior to any expensive and time consuming chemical procedures and analyses, the resulting powdered samples, after manual homogenisation, are measured for more than twenty-two major and trace elements using non-destructive X-Ray fluorescence (XRF) methods. This approach provides lots of valuable geochemical data which documents the natural geochemical processes which occur in the peat profiles and their possible effect on the trace metal profiles. The development, evaluation and use of peat cores from bogs as archives of high-resolution records of atmospheric deposition of mineral dust and trace elements have led to the development of many analytical procedures which now permit the measurement of a wide range of elements in peat samples such as lead and lead isotope ratios, mercury, arsenic, antimony, silver, molybdenum, thorium, uranium, rare earth elements. Radiometric methods (the carbon bomb pulse of (14)C, (210)Pb and conventional (14)C dating) are combined to allow reliable age-depth models to be reconstructed for each peat profile.