Collaborative Understanding of Cyanobacteria in Lake Ecosystems

We describe a collaboration between mathematicians and ecologists studying the cyanobacterium Gloeotrichia echinulata and its possible role in eutrophication of New England lakes. The mathematics includes compartmental modeling, differential equations, difference equations, and testing models against high-frequency data. The ecology includes observation, field sampling, and parameter estimation based on observed data and the related literature. Mathematically and ecologically, a collaboration like this progresses in ways it never would have if either group worked alone

Predicting the effects of climate change on freshwater cyanobacterial blooms requires consideration of the complete cyanobacterial life cycle

To date, most research on cyanobacterial blooms in freshwater lakes has focused on the pelagic life stage. However, examining the complete cyanobacterial life cycle—including benthic life stages—may be needed to accurately predict future bloom dynamics. The current expectation, derived from the pelagic life stage, is that blooms will continue to increase due to the warmer temperatures and stronger stratification associated with climate change. However, stratification and mixing have contrasting effects on different life stages: while pelagic cyanobacteria benefit from strong stratification and are adversely affected by mixing, benthic stages can benefit from increased mixing. The net effects of these potentially counteracting processes are not yet known, since most aquatic ecosystem models do not incorporate benthic stages and few empirical studies have tracked the complete life cycle over multiple years. Moreover, for many regions, climate models project both stronger stratification and increased storm-induced mixing in the coming decades; the net effects of those physical processes, even on the pelagic life stage, are not yet understood. We therefore recommend an integrated research agenda to study the dual effects of stratification and mixing on the complete cyanobacterial life cycle—both benthic and pelagic stages—using models, field observations and experiments

Spatial and Temporal Variability in Recruitment of the Cyanobacterium Gloeotrichia echinulata in an Oligotrophic Lake

Recruitment from dormant stages in the benthos can provide a critically important inoculum for surface populations of phytoplankton, including bloom-forming cyanobacteria. For example, water-column populations of the large (1–3-mm diameter) colonial cyanobacterium Gloeotrichia echinulata (Smith) P. Richter can be strongly subsidized by benthic recruitment. Therefore, understanding controls on recruitment is essential to an investigation of the factors controlling Gloeotrichiablooms, which are increasing in low-nutrient lakes across northeastern North America. We quantified surface abundances and recruitment from littoral sediments at multiple near-shore sampling sites in oligotrophic Lake Sunapee, New Hampshire, USA, during the summers of 2005–2012 and used this data set—the longest known record of cyanobacterial recruitment—to investigate potential drivers of interannual differences in Gloeotrichia recruitment. We found extensive spatiotemporal variability in recruitment. Recruitment was higher at some sites than others, and within seasons, recruitment into replicate traps at the same site was generally more similar than recruitment at different sites. These data suggest that local factors, such as substrate quality or the size of the seed bank, may be important controls on recruitment. Benthic recruitment probably accounted forGloeotrichia recruitment may be related to regional climatic variability

Cyanobacteria as biological drivers of Lake Nitrogen and Phosphorus Cycling

Here we draw attention to the potential for pelagic bloom‐forming cyanobacteria to have substantial effects on nutrient cycling and ecosystem resilience across a wide range of lakes. Specifically, we hypothesize that cyanobacterial blooms can influence lake nutrient cycling, resilience, and regime shifts by tapping into pools of nitrogen (N) and phosphorus (P) not usually accessible to phytoplankton. The ability of many cyanobacterial taxa to fix dissolved N2 gas is a well‐known potential source of N, but some taxa can also access pools of P in sediments and bottom waters. Both of these nutrients can be released to the water column via leakage or mortality, thereby increasing nutrient availability for other phytoplankton and microbes. Moreover, cyanobacterial blooms are not restricted to high nutrient (eutrophic) lakes: blooms also occur in lakes with low nutrient concentrations, suggesting that changes in nutrient cycling and ecosystem resilience mediated by cyanobacteria could affect lakes across a gradient of nutrient concentrations. We used a simple model of coupled N and P cycles to explore the effects of cyanobacteria on nutrient dynamics and resilience. Consistent with our hypothesis, parameters reflecting cyanobacterial modification of N and P cycling alter the number, location, and/or stability of model equilibria. In particular, the model demonstrates that blooms of cyanobacteria in low‐nutrient conditions can facilitate a shift to the high‐nutrient state by reducing the resilience of the low‐nutrient state. This suggests that cyanobacterial blooms warrant attention as potential drivers of the transition from a low‐nutrient, clear‐water regime to a high‐nutrient, turbid‐water regime, a prediction of particular concern given that such blooms are reported to be increasing in many regions of the world due in part to global climate change

Onshore Wind Speed Modulates Microbial Aerosols along an Urban Waterfront

Wind blowing over aquatic and terrestrial surfaces produces aerosols, which include microbial aerosols. We studied the effect of onshore wind speeds on aerosol concentrations as well as total and culturable microbial aerosols (bacterial and viral) at an urban waterfront (New York, NY, USA). We used two distinct methods to characterize microbial aerosol responses to wind speed: A culture-based exposure-plate method measuring viable bacterial deposition near-shore (CFU accumulation rate); and a culture-independent aerosol sampler-based method measuring total bacterial and viral aerosols (cells m−3 air). While ambient coarse (\u3e2 µm) and fine (0.3–2 µm) aerosol particle number concentrations (regulated indicators of air quality) decreased with increasing onshore wind speeds, total and depositing culturable bacterial aerosols and total viral aerosols increased. Taxonomic identification of the 16S rDNA of bacterial aerosol isolates suggested both terrestrial and aquatic sources. Wind appears to increase microbial aerosol number concentrations in the near-shore environment by onshore transport at low wind speeds (s−1 ), and increased local production and transport of new microbial aerosols from adjacent water surfaces at higher wind speeds (\u3e4 m s−1 ). This study demonstrates a wind-modulated microbial connection between water and air in the coastal urban environment, with implications for public health management and urban microbial ecology

Integrating Science and Policy: A Case Study of the Hubbard Brook Research Foundation Science Links Program

Scientists, related professionals, and the public have for decades called for greater interaction among scientists, policymakers, and the media to address contemporary environmental challenges. Practical examples of effective “real-world” programs designed to catalyze interactions and provide relevant science are few. Existing successful models can be used, however, to develop and expand the work of integrating, synthesizing, and communicating ecosystem science for environmental policy and natural-resource management. We provide an overview of the structure and strategies used in the Hubbard Brook Research Foundation Science Links program, now in its thirteenth year as a successful boundary-spanning organization. We detail project activities and results and share lessons and challenges for the further advancement of Science Links and other efforts to bridge the science–policy divide. Furthermore, we suggest greater emphasis in boundary-spanning programs as a part of publicly funded research initiatives and as legitimate scholarly endeavors that support the scaled coproduction of knowledge and that harness scientific research to support informed policy and environmental management

Mental health of UK military personnel while on deployment in Iraq

Background Most research on the mental health of UK armed forces personnel has been conducted either before or after deployment; there is scant evidence concerning personnel while they are on deployment. Aims To assess the mental health of UK armed forces personnel deployed in Iraq and identify gaps in the provision of support on operations. Method Personnel completed a questionnaire about their deployment experiences and health status. Primary outcomes were psychological distress (General Health Questionnaire–12, GHQ–12), symptoms of post-traumatic stress disorder (PTSD) and self-rating of overall health. Results Of 611 participants, 20.5% scored above the cut-off on the GHQ–12 and 3.4% scored as having probable PTSD. Higher risk of psychological distress was associated with younger age, female gender, weaker unit cohesion, poorer perceived leadership and non-receipt of a pre-deployment stress brief. Perceived threat to life, poorer perceived leadership and non-receipt of a stress brief were risk factors for symptoms of PTSD. Better self-rated overall health was associated with being a commissioned officer, stronger unit cohesion and having taken a period of rest and recuperation. Personnel who reported sick for any reason during deployment were more likely to report psychological symptoms. Around 11% reported currently being interested in receiving help for a psychological problem. Conclusions In an established operational theatre the prevalence of common psychopathology was similar to rates found in non-deployed military samples. However, there remains scope for further improving in-theatre support mechanisms, raising awareness of the link between reporting sick and mental health and ensuring implementation of current policy to deliver pre-deployment stress briefs

Networked lake science: how the Global Lake Ecological Observatory Network (GLEON) works to understand, predict and communicate lake ecosystem response to global change

The Global Lake Ecological Observatory Network (GLEON) has built an international, grassroots network of scientists and citizens, data, and lake observatories to advance understanding of lake ecosystems. Through careful attention to the professional needs and aspirations of a community, GLEON has formed as its foundation the trust and respect essential to product-based network science. As a consequence, GLEON is making significant advancements in lake ecosystem understanding through all “five legs of the table that support scientific understanding”—natural history, multiscale data, experiments, theory, and comparative studies—with particular emphasis on multiscale data and comparative studies. Technical products, such as cyberinfrastructure in support of network data and operations, software tools for calculating lake physical metrics (e.g., thermocline depth, buoyancy frequency, Schmidt stability), and lake metabolism, as well as ecosystem-scale numerical simulation software, have derived from GLEON collaborations and have become community resources catalyzing interdisciplinary science. Education and outreach initiatives have served to engage citizens from outside the traditional boundaries of academia directly in research. Moreover, these cross-boundary collaborations have provided essential links to lake and reservoir stakeholders who have informed how science is prioritized and communicated within GLEON. As a grassroots network, GLEON derives its momentum, flexibility, and impact from its talented members, who are committed to the future sustainability of lakes and reservoirs and the services they provide

Insights from the Global Lake Ecological Observatory Network (GLEON)

The Global Lake Ecological Observatory Network (GLEON) is a grass-roots network of people, data, and observatories. The network represents a unique effort to bring together a diverse community of scientists, engineers, information technology experts, and engaged stakeholders to understand, conserve, and predict the state of lakes and reservoirs globally. Individuals and teams in GLEON have generated a range of scientific, educational, and outreach products, from software tools to scientific publications to education modules and programs. This special issue of Inland Waters brings together a series of papers generated from the network. Here, we discuss the foundations of GLEON that have facilitated these publications and others like them in terms of network structure, research areas, and the threads that tie the network together. GLEON is underpinned by sophisticated analytical tools and a network of high-frequency in situ observatories that exploit advanced sensors and associated technologies. This approach expands the space and time domains available to inquiry and analysis of lake processes. Using team science, the network has also established a culture of collaboration, sharing, and trust. This flexible framework allows GLEON members to advance research on a range of topics and has led to an increasing number of collaborative cross-site products. Future success will depend on the network’s ability to continue to facilitate the successes of its members while also being responsive to evolving member needs, technologies, and societal priorities

The soil and plant biogeochemistry sampling design for The National Ecological Observatory Network

Human impacts on biogeochemical cycles are evident around the world, from changes to forest structure and function due to atmospheric deposition, to eutrophication of surface waters from agricultural effluent, and increasing concentrations of carbon dioxide (CO2) in the atmosphere. The National Ecological Observatory Network (NEON) will contribute to understanding human effects on biogeochemical cycles from local to continental scales. The broad NEON biogeochemistry measurement design focuses on measuring atmospheric deposition of reactive mineral compounds and CO2 fluxes, ecosystem carbon (C) and nutrient stocks, and surface water chemistry across 20 eco‐climatic domains within the United States for 30 yr. Herein, we present the rationale and plan for the ground‐based measurements of C and nutrients in soils and plants based on overarching or “high‐level” requirements agreed upon by the National Science Foundation and NEON. The resulting design incorporates early recommendations by expert review teams, as well as recent input from the larger natural sciences community that went into the formation and interpretation of the requirements, respectively. NEON\u27s efforts will focus on a suite of data streams that will enable end‐users to study and predict changes to biogeochemical cycling and transfers within and across air, land, and water systems at regional to continental scales. At each NEON site, there will be an initial, one‐time effort to survey soil properties to 1 m (including soil texture, bulk density, pH, baseline chemistry) and vegetation community structure and diversity. A sampling program will follow, focused on capturing long‐term trends in soil C, nitrogen (N), and sulfur stocks, isotopic composition (of C and N), soil N transformation rates, phosphorus pools, and plant tissue chemistry and isotopic composition (of C and N). To this end, NEON will conduct extensive measurements of soils and plants within stratified random plots distributed across each site. The resulting data will be a new resource for members of the scientific community interested in addressing questions about long‐term changes in continental‐scale biogeochemical cycles, and is predicted to inspire further process‐based research