Stephen B. Weisberg

Background: Children may be at higher risk for swimming-associated illness following exposure to fecally-contaminated recreational waters. We analyzed a pooled data set of over 80,000 beachgoers from 13 beach sites across the United States to compare risks associated with the fecal indicator bacteria Enterococcus spp. (measured by colony forming units, CFU and quantitative polymerase chain reaction cell equivalents, qPCR CE) for different age groups across different exposures, sites and health endpoints. Methods: Sites were categorized according to the predominant type of fecal contamination (human or non-human). Swimming exposures of varying intensity were considered according to degree of contact and time spent in the water. Health endpoints included gastrointestinal and respiratory symptoms and skin rashes. Logistic regression models were used to analyze the risk of illness as a function of fecal contamination in water as measured by Enterococcus spp. among the exposed groups. Non-swimmers (those who did not enter the water) were excluded from the models to reduce bias and facilitate comparison across groups. Results: Gastrointestinal symptoms were the most sensitive health endpoint and strongest associations were observed with Enterococcus qPCR CE at sites impacted by human fecal contamination. Under several exposure scenarios, associations between illness and Enterococcus spp. levels were significantly higher among children compared to adolescents and adults. Respiratory symptoms were also associated with Enterococcus spp. exposures among young children at sites affected by human fecal sources, although small sample sizes resulted in imprecise estimates for these associations. Conclusion: Under many exposure scenarios, children were at higher risk of illness associated with exposure to fecal contamination as measured by the indicator bacteria Enterococcus spp. The source of fecal contamination and the intensity of swimming exposure were also important factors affecting the association between Enterococcus spp. and swimming-associated illness.

The rapid emergence of wastewater based surveillance has led to a wide array of SARS-CoV-2 RNA quantification methodologies being employed. Here we compare methods to store samples, inactivate viruses, capture/concentrate viruses, and extract/measure viral RNA from primary influent into wastewater facilities. We found that heat inactivation of the viruses led to a 1-3 log ₁₀ decrease compared to chemical inactivation. Freezing influent prior to concentration caused a 1-4 log ₁₀ decrease compared to processing fresh samples, but viral capture by membrane adsorption prior to freezing was robust to freeze-thaw variability. Concentration vs. direct extraction, and PCR platform also affected outcome, but by a smaller amount. The choice of nucleocapsid gene target had nearly no effect. Pepper mild-mottle virus was much less sensitive to these methodological differences than was SARS-CoV-2, which challenges its use as a population-level control among studies using different methods. Better characterizing the variability associated with different methodologies, in particular the impact of methods on sensitivity, will aid decision makers in following the effects of vaccination campaigns, early detection of future outbreaks, and potentially monitoring the appearance of SARS-CoV-2 variants in the population.

Recent evidence suggests that microplastic particles are pervasive and potentially of great risk to both animal and human health. The California legislature has responded to this information by enacting two new bills that require quantification of microplastics in various media and development of new management strategies to address microplastic pollution. However, there are several scientific gaps that impede the development and implementation of necessary management strategies to address microplastic pollution. In this paper, we use the California experience as a case study to provide perspective on those science gaps, the current barriers to science affecting management, and the actions scientists can take to best ensure their efforts are of greatest value to policymakers and the management community.

There are numerous reasons to conduct scientific research within protected areas, but research activities may also negatively impact organisms and habitats, and thus conflict with a protected area’s conservation goals. We developed a quantitative ecological decision-support framework that estimates these potential impacts so managers can weigh costs and benefits of proposed research projects and make informed permitting decisions. The framework generates quantitative estimates of the ecological impacts of the project and the cumulative impacts of the proposed project and all other projects in the protected area, and then compares the estimated cumulative impacts of all projects with policy-based acceptable impact thresholds. We use a series of simplified equations (models) to assess the impacts of proposed research to: a) the population of any targeted species, b) the major ecological assemblages that make up the community, and c) the physical habitat that supports protected area biota. These models consider both targeted and incidental impacts to the ecosystem and include consideration of the vulnerability of targeted species, assemblages, and habitats, based on their recovery time and ecological role. We parameterized the models for a wide variety of potential research activities that regularly occur in the study area using a combination of literature review and expert judgment with a precautionary approach to uncertainty. We also conducted sensitivity analyses to examine the relationships between model input parameters and estimated impacts to understand the dominant drivers of the ecological impact estimates. Although the decision-support framework was designed for and adopted by the California Department of Fish and Wildlife for permitting scientific studies in the state-wide network of marine protected areas (MPAs), the framework can readily be adapted for terrestrial and freshwater protected areas.

Distinguishing between local, anthropogenic nutrient inputs and large‐scale climatic forcing as drivers of coastal phytoplankton biomass is critical to developing effective nutrient management strategies. Here we assess the relative importance of these two drivers by comparing trends in chlorophyll‐a between shallow coastal (0.1–16.5 km) and deep offshore (17–700 km) areas, hypothesizing that coastal regions influenced by anthropogenic nutrient inputs may have different spatial and temporal patterns in chlorophyll‐a concentration from offshore regions where coastal inputs are less influential. Quarterly conductivity‐temperature‐depth (CTD) fluorescence measurements collected from three southern California continental shelf regions since 1998 were compared to chlorophyll‐a data from the more offshore California Cooperative Fisheries Investigations (CalCOFI) program. The trends in the coastal zone were similar to those offshore, with a gradual increase of chlorophyll‐a biomass and shallowing of its maximum layer since the beginning of observations, followed by chlorophyll‐a declining and deepening from 2010 to present. An exception was the northern coastal part of SCB, where chlorophyll‐a continued increasing after 2010. The long‐term increase in chlorophyll‐a prior to 2010 was correlated with increased nitrate concentrations in deep waters, while the recent decline was associated with deepening of the upper mixed layer, both linked to the low‐frequency climatic cycles of the Pacific Decadal Oscillation and North Pacific Gyre Oscillation. These large‐scale factors affecting the physical structure of the water column may also influence the delivery of nutrients from deep ocean outfalls to the euphotic zone, making it difficult to distinguish the effects of anthropogenic inputs on chlorophyll along the coast.