Autonomous underwater glider observations in southern Lake Ontario and Niagara River plume.

The nearshore areas of the Laurentian Great Lakes provide valuable ecosystem services including habitat for a variety of species and water for surrounding communities. Recent declines in nearshore water quality have increased the need for understanding the connectivity between nearshore and offshore areas; however, observing water quality variability across the dynamic nearshore to offshore transition zone poses logistical challenges for traditional observing systems. Here we evaluate cross-shore and along-shore water quality gradients using observations from two three-week deployments of a Slocum autonomous glider in southern Lake Ontario. The glider was deployed between the Niagara River mouth and Rochester, NY during early and late summer 2018, and each deployment resulted in over 3000 vertical profiles of the water column, and several transects between 2 km and 20 km from shore. In early summer, the cross-shore chlorophyll gradient was characterized by highest values just below the surface, at the frontal zone between weakly stratified conditions closer to shore and unstratified conditions offshore. In late summer, stratified conditions extended across the entire survey area. The depth of the thermocline was deeper and chlorophyll values were lower within 10 km of shore than offshore, where the highest chlorophyll values were observed in a distinct layer below the thermocline. In both early and late summer, the frontal boundary indicated by the cross-shore chlorophyll gradient was located below the surface and well offshore of what is typically considered the nearshore zone but was within the width of the coastal boundary layer. The high-resolution glider observations provide a detailed view of patterns of variability across a dynamic coastal zone and pinpoint the cross-shore frontal boundary that may be important for biologists to differentiate biological communities.

The wind-driven formation of cross-shelf sediment plumes in a large lake.

Wind-driven turbidity plumes frequently occur in the western arm of Lake Superior and may represent a significant cross shelf transport mechanism for sediment, nutrient and biota. Here we characterize a plume that formed in late April 2016 using observations from in situ sensors and remote sensing imagery, and estimate the volume of cross shelf transport using both the observations and an idealized analytical model of plume formation. The steady-state, barotropic model is used to determine a relationship between the intensity and duration of a wind event and the volume of water transported from nearshore to offshore during the event. The model transport is the result of nearshore flow in the direction of the wind and a pressure-gradient-driven counter flow in the deeper offshore waters, consistent with observations. The volume of offshore transport associated with the 2016 plume is estimated by both methods to have been on the order of 1010 m3. Analysis of similar events from 2008-2016 shows a strong relationship between specific wind impulse and plume volume. Differences in the intensity and duration of individual events as well as ice cover, which prevents plume formation, lead to interannual variability of offshore transport ranging over an order of magnitude and illustrates how wind-driven processes may contribute to interannual variability of ecosystem functioning.

Modeling nearshore-offshore exchange in Lake Superior.

Lake Superior's ecosystem includes distinct nearshore and offshore food webs linked by hydrodynamic processes that transport water and tracers along and across shore. The scales over which these processes occur and their sensitivity to increasing summer surface temperatures are not well understood. This study investigated horizontal mixing between nearshore and offshore areas of Lake Superior over the 10-year period from 2003 to 2012 using a realistically forced three-dimensional numerical model and virtual tracers. An age tracer was used to characterize the time scales of horizontal mixing between nearshore areas of the lake where water depth is less than 100 m and deeper areas. The age of water in nearshore areas increased and decreased in an annual cycle corresponding to the lake's dimictic cycle of vertical mixing and stratification. Interannual variability of mixing in the isothermal period was significantly correlated to average springtime wind speed, whereas variability during the stratified season was correlated to the average summer surface temperature. Dispersal of a passive tracer released from nine locations around the model lake's perimeter was more extensive in late summer when stratification was established lakewide than in early summer. The distribution of eddies resolved in the model reflected differences between the early and late summer dispersal patterns. In the eastern part of the lake dispersal was primarily alongshore, reflecting counterclockwise coastal circulation. In the western part of the lake, cross-shore mixing was enhanced by cross-basin currents.

Tale of Two Storms: Impact of Extreme Rain Events on the Biogeochemistry of Lake Superior.

Climate change is expected to profoundly affect the Great Lakes region of North America. An increase in intensity and frequency of rain events is anticipated to deliver more runoff and to increase riverine inputs to Lake Superior's ecosystem. The effects of these changes on key biogeochemical parameters were analyzed by coupling satellite data, water column sensor profiles, and discrete surface-water sampling after two "500-year" flood events in the Lake Superior basin. This study provides both a spatial and a temporal sense of how plumes interacted within the ecosystem. We also determined the significant differences in water quality parameters for plume versus non-plume waters. These two plumes were important for delivery of nutrients, with variable transport of sediments and colored dissolved organic matter (CDOM). Data from the 2012 storm event showed a significant input of total nitrogen (TN), total phosphorous (TP) and CDOM to the system. In the 2016 storm event, carbon cycling parameters (acidity, total inorganic carbon (TIC), and dissolved organic carbon (DOC), and ammonia levels were elevated within the plume. In neither storm event was there a significant difference in chlorophyll a between plume and non-plume waters during our sampling cruises. These two plume events were similar in amount of precipitation, but their effect on the biogeochemistry of Lake Superior varied due to differences in the watersheds where the rain fell. The studied plume events were dynamic, changing with currents, winds and the settling of suspended sediments.

Support for a fluid-continuum model of sexual orientation: a large-scale Internet study.

In a study with 17,785 subjects obtained over the Internet from the United States and 47 other countries, Kinsey's hypothesis that sexual orientation lies on a continuum was supported. Self-identifications of subjects as gay, straight, bisexual, and other corresponded to broad, skewed distributions, suggesting that such terms are misleading for many people. Sexual orientation range-roughly, how much flexibility someone has in expressing sexual orientation-was also measured. The results support a fluid-continuum model of sexual orientation, according to which genetic and environmental factors determine both the size of the sexual orientation range and the point at which an individual's sexual orientation is centered on the continuum.

Occupational exposure to trichloroethylene and cancer risk for workers at the Paducah Gaseous Diffusion Plant.

OBJECTIVE: The Paducah Gaseous Diffusion Plant (PGDP) became operational in 1952; it is located in the western part of Kentucky. We conducted a mortality study for adverse health effects that workers may have suffered while working at the plant, including exposures to chemicals. MATERIALS AND METHODS: We studied a cohort of 6820 workers at the PGDP for the period 1953 to 2003; there were a total of 1672 deaths to cohort members. Trichloroethylene (TCE) is a specific concern for this workforce; exposure to TCE occurred primarily in departments that clean the process equipment. The Life Table Analysis System (LTAS) program developed by NIOSH was used to calculate the standardized mortality ratios for the worker cohort and standardized rate ratio relative to exposure to TCE (the U.S. population is the referent for ageadjustment). LTAS calculated a significantly low overall SMR for these workers of 0.76 (95% CI: 0.72-0.79). A further review of three major cancers of interest to Kentucky produced significantly low SMR for trachea, bronchus, lung cancer (0.75, 95% CI: 0.72-0.79) and high SMR for Non-Hodgkin's lymphoma (NHL) (1.49, 95% CI: 1.02-2.10). RESULTS: No significant SMR was observed for leukemia and no significant SRRs were observed for any disease. Both the leukemia and lung cancer results were examined and determined to reflect regional mortality patterns. However, the Non-Hodgkin's Lymphoma finding suggests a curious amplification when living cases are included with the mortality experience. CONCLUSIONS: Further examination is recommended of this recurrent finding from all three U.S. Gaseous Diffusion plants.

Brain cancer survival in Kentucky: 1996-2000.

This is a report of brain cancer survival patterns in certain Area Development Districts (ADDs) in Kentucky, the state, and the nation. Brain cancer is of national and regional concern as it is a disease of high case fatality rates and relatively short survival. Comparisons for survival were made between the U.S.A. and the state. Kentucky has higher brain cancer mortality rates than the U.S.A., but significantly better cause-specific survival (p < 0.05). In order to examine within state variations for brain cancer survival, data organized for the fifteen ADDs from the state's central cancer registry were used. The analytic focus of this analysis were three regions expressly: the Purchase ADD (location of the Paducah Gaseous Diffusion Plant), the Green River ADD (the location of elevated brain cancer mortality rates), and the Kentucky River ADD (comprising counties that each have significantly more than the state average of persons living below the national poverty level). We found no evidence of lower survival for brain cancer among the poorer region of the state. The western districts were found to have lower cause-specific survival than the state (p < 0.05) and the U.S.A. Such a regional variation alerts population-based researchers to consider varying survival trends within the state's population.