Increased operational costs of electricity generation in the Delaware River and Estuary from salinity increases due to sea-level rise and a deepened channel.

Like many estuaries in the world, salinity levels in the Delaware River and Estuary are expected to increase due to a deepened navigational channel and sea-level rise. This study estimated operational cost increases resulting from increased ambient salinity likely to be incurred at PSEG-Hope Creek, an evaporatively cooled electricity generating station. To estimate cost increases, a linked physical-economic model was developed to generate daily forecasts of salinity and the resulting changes in facility's cooling water treatment and pumping requirements. Salinity increases under potential future bathymetric configurations were simulated using a hydrodynamic model. On an equivalent annual basis (discounted at 5%), average cost increases were $0.4M per year, or approximately 0.1% of estimated total annual operating costs for the facility. Methods developed here could be employed at other facilities anticipating future salinity increases. Results inform cost-benefit analyses for dredging projects and contribute to estimates of the indirect costs to society from carbon emissions through sea-level rise. Future research refinements can focus on modeling changes in suspended sediment concentrations and estimating their impacts on operational costs.

Laboratory-based measurements of swimming performance and related metabolic rates of field-sampled smallmouth buffalo (Ictiobus bubalus): a study of seasonal changes.

Numerous studies have demonstrated how the performance physiology of fish may change when they are acclimated to designated laboratory temperatures, but few researchers have examined naturally occurring seasonal effects on several physiological parameters associated with swimming performance. Using field-acclimatized smallmouth buffalo (Ictiobus bubalus) collected each season, we report significant seasonal effects in the following variables: critical swimming speed (modified), metabolic rate (standard, active, and scope for activity), and swimming efficiency (total and net cost of transport). Underlying seasonal changes in performance was the reproductive cycle of buffalo, particularly the period of fall gonadal recrudescence. Compared with spring, fall buffalo had a significantly lower mean critical swimming speed (72%) and lower active metabolic rate (53%), even when tested at similar temperatures. During spring, buffalo had a high mean critical swimming speed and low net cost of transport in comparison with other seasons. Buffalo are known to participate in a spring migration and spawning that may require the increased performance and efficiency observed during that season. In addition, significant sex effects were detected in winter measurements of standard metabolic rate and net cost of transport, with females the more efficient swimmers.

Early life-stage effects in medaka (Oryzias latipes) following in ovo exposure to polyamine biosynthetic inhibitors.

Medaka, Oryzias latipes, were exposed in ovo to the polyamine (PA) biosynthesis inhibitors alpha-difluoromethylornithine (DFMO) and methylglyoxal bis(guanylhydrazone) (MGBG). In an additional group, spermine, the end product of the PA pathway, was added with DFMO and MGBG for a "rescue" treatment. At 4 days posthatch, length, DNA and RNA content, and swimming endurance were measured. The only parameter affected by treatment was swimming endurance which revealed decreased latent time to fatigue with increased dose, although not statistically significant. The rescue group, however, did demonstrate a statistically significant decrease in fatigue latency as compared to controls.