Ontogeny of feeding behavior and cranial morphology in the whitespotted bambooshark <Emphasis Type="Italic">Chiloscyllium plagiosum</Emphasis>

Morphological and behavioral development of the feeding apparatus over early ontogeny can profoundly affect the ability of an organism to obtain nourishment, ultimately impacting survival. The interplay between morphology and behavior over the first year of life was studied in the whitespotted bambooshark Chiloscyllium plagiosum (Bennett 1830) beginning in March of 2002 using high-speed videography and dissection. Externally measured variables describing cranial growth, and jaw weight, scaled at or near isometry while jaw and hyoid musculature, especially the coracohyoideus, demonstrated considerable hypertrophication. The difference between the volume of the buccal cavity when open and closed scaled with substantial positive allometry while the time to reach maximum jaw and hyoid abduction exhibited weak allometry, resulting in the capacity for more rapid and greater volumetric intake during feeding. In addition, the relative forward motion of the predator during a strike decreased over ontogeny and the feeding modality became more suction-dominated. Kinematic variables exhibited little variability and the primary aspect of food capture that was modulated in response to food type was the forward motion of the predator. An increase in capture success was noted for live, elusive shrimp over ontogeny indicating that morphological and behavioral changes have direct consequences for prey acquisition. Conservation of head shape coupled with a narrow behavioral repertoire is hypothesized to increase prey capture success in the wild over ontogeny as individuals become more proficient in the execution of a single, low-variability, suction-dominated capture behavior.     

Ammonia emissions from Swine waste lagoons in the Utah great basin

In animal production systems (poultry, beef, and swine), current production, storage, and disposal techniques present a challenge to manage wastes to minimize the emissions of trace gases within relatively small geographical areas. Physical and chemical parameters were measured on primary and secondary lagoons on three different swine farming systems, three replicates each, in the Central Great Basin of the United States to determine ammonia (NH3) emissions. Nutrient concentrations, lagoon water temperature, and micrometeorological data from these measurements were used with a published process model to calculate emissions. Annual cycling of emissions was determined in relation to climatic factors and wind speed was found the predominating factor when the lagoon temperatures were above about 3 degrees C. Total NH3 emissions increased in the order of smallest to largest: nursery, sow, and finisher farms. However, emissions on an animal basis increased from nursery animals being lowest to sow animals being highest. When emissions were compared to the amount of nitrogen (N) fed to the animals, NH3 emissions from sows were lowest with emissions from finisher animals highest. Ammonia emissions were compared to similar farm production systems in the humid East of the United States and found to be similar for finisher animals but had much lower emissions than comparable humid East sow production. Published estimates of NH3 emissions from lagoons ranged from 36 to 70% of feed input (no error range) compared to our emissions determined from a process model of 9.8% with an estimated range of +/-4%.     

Phylogeography of California and Galápagos sea lions and population structure within the California sea lion

We investigate the phylogeography of California (Zalophus californianus) and Galápagos (Z. wollebaeki) sea lions and describe within-population structure for the California sea lion based on mitochondrial DNA. Fifty control-region haplotypes were found, 41 from Z. californianus and 9 from Z. wollebaeki, with three fixed differences between the two species. Ranked population boundaries along the range of Z. californianus were defined based on the Monmonier Maximum Difference Algorithm, resulting in five genetically distinct populations, two in the Pacific Ocean and three inside the Gulf of California. A Minimum Spanning Network showed a strong phylogeographic signal with two well-defined clusters, Z. californianus and Z. wollebaeki, separated by six base-pair differences, supporting the existence of two genetically distinct species with an estimated divergence time of ~0.8 Ma. Results are discussed in the context of the historical geologic and paleoceanographic events of the last 1 Ma in the eastern Pacific.     

Sorption and transformation of biocides from hydraulic fracturing in the Marcellus Shale: a review

Environmental Chemistry Letters - Biocides are applied as chemical additives in hydraulic fracturing fluids to control subsurface microbial activity. When biocides are released into the subsurface,...