Location, identification, and size distribution of depleted uranium grains in reservoir sediments

The location, nature, and size distribution of uranium-rich grains in sediment layers can be identified by sunbursts of etched particle tracks if each sample is pressed against a track detector, next irradiated with thermal neutrons, and the detectors then chemically etched to reveal fission tracks. The total track abundance from the sample is a measure of the 235U content; hence, if the bulk uranium (mostly 238U) has been measured, the two sets of results give the depletion or enrichment of the uranium. Sunbursts of tracks mark the locations of low-abundance, high-uranium grains allowing them to be singled out for further study.     

Genetic variation in the eel. III. Comparisons of Rhode Island and Icelandic populations. Implications for the Atlantic eel problem

The frequencies of certain electrophoretic fractions of esterases, transferrins and haemoglobins in an American sample of eels (Anguilla rostrata Le Sueur) are compared to those in a sample from Iceland [A. anguilla (L.)]. A number of quantitative differences were established as well as 6 contrasts of a qualitative all-or-none type. The bearing of these differences and contrasts on theories concerning a separate or a single gene pool for Atlantic eels is discussed.     

Ancient Maya drained field agriculture: Its possible application today in the New River Floodplain,Belize C.A.

A drained field complex was identified in the New River near Lamanai, with evidence of Pre-Classic and Classic Mesoamerican occupation. X-ray diffraction analysis of alluvium indicated a dominance of gypsum and a natural sedimentary origin for the fields. Weathering by percolating solutions eliminates the gypsum leaving montmorillonite clay. Sediments deposited on the drained fields during flooding are in excess of 890 kg/ha/year, with an organic content of >50%. As water levels drop, exchangeable bases are leached. The presence of montmorillonite in Layers 1 and 3 and the high CEC of the clay fraction account for the low permeability and high potential productivity of these soils for agriculture. The indication of high levels of inorganic P in Layer 3 is taken as a sign that the layer was the ancient planting surface. By clearing the present forest cover, local farmers would have a nutrient-rich soil suitable for agriculture, that their ancestors also exploited for many centuries.     

A 40+ year record of Cd,Hg, Pb,and U deposition in sediments of Patroon Reservoir,Albany County,NY, USA

Sediments of the Patroon Creek watershed (33 km(2)) are known to contain significant concentrations of heavy metals derived from two industrial sites within the watershed. Mercury Refining, Inc (Mereco) has stored and recycled Hg from 1955 to the present day, and National Lead Industries (NLI) manufactured aircraft components containing Cd, Pb, and U from 1958 to 1984. Here we present the first record of heavy metal deposition as preserved in a 3-m long sediment core collected in 1999 from Patroon Reservoir, a small water body (1.3 ha) downstream of the industrial sites. Bulk sediment samples were collected from the core at 0.05-m intervals and analyzed for total Cd, Pb, and U by ICP-MS and total Hg by CVAAS. Total Hg increases from less than 1 mg kg(-1) (dw) below 1.68 m, to a maximum of 6.2 mg kg(-1) at 0.80 m, and then declines to the sediment-water interface. Total Cd, Pb, and U concentrations increase abruptly above 1.68 m to maximum values of 25, 320, and 3600 mg kg(-1) (dw), respectively, and then decline gradually upwards. By correlating metal profiles with industrial history, we conclude that the 1.68 m horizon was deposited no earlier than 1958, the beginning of aircraft component manufacturing at NLI. The average, apparent sedimentation rate within the reservoir has a minimum value of approximately 0.04 m year(-1) for the 41-year period from 1958 to 1999. In the interval 0--1.68 m, average concentrations of Cd, Hg, Pb, and U are 1.69, 1.50, 461, and 13 mg kg(-1), respectively. These levels are comparable with other lake, reservoir and stream sediments that have been moderately to severely impacted by industrial pollution and are above levels expected to be detrimental to aquatic organisms.     

Wild elephant (Loxodonta africana) breeding herds respond to artificially transmitted seismic stimuli

Seismic communication is known to be utilized in insects, amphibians, reptiles, and small mammals, but its use has not yet been documented in large mammals. Elephants produce low-frequency vocalizations, and these vocalizations have seismic components that propagate in the ground, but it has not yet been demonstrated that elephants can detect or interpret these seismic signals. In this study, we played back seismic replicates of elephant alarm vocalizations to herds of wild African elephants in their natural environment and observed significant behavioral changes indicating that they had detected these signals. Seismic communication may provide an important complement to existing communication modes used by elephants. Seismic sensitivity may also provide elephants with an additional modality for sensing important environmental cues such as changes in weather patterns or seismic disturbances.