Craig E. Williamson

Craig E. Williamson
Miami University | MU · Department of Biology

PhD Dartmouth College

About

192
Publications
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13,228
Citations

Publications

Publications (192)
Article
Full-text available
The Environmental Effects Assessment Panel of the Montreal Protocol under the United Nations Environment Programme evaluates effects on the environment and human health that arise from changes in the stratospheric ozone layer and concomitant variations in ultraviolet (UV) radiation at the Earth’s surface. The current update is based on scientific a...
Article
Full-text available
Climate change and other anthropogenic stressors have led to long-term changes in the thermal structure, including surface temperatures, deepwater temperatures, and vertical thermal gradients, in many lakes around the world. Though many studies highlight warming of surface water temperatures in lakes worldwide, less is known about long-term trends...
Article
The Montreal Protocol and its Amendments have been highly effective in protecting the stratospheric ozone layer and preventing global increases in solar ultraviolet‐B radiation (UV‐B; 280‐315 nm) at Earth’s surface (McKenzie et al., 2019). This international agreement has also been one of the most important societal actions to mitigate global warmi...
Article
Full-text available
Reductions in ice cover duration and earlier ice breakup are two of the most prevalent responses to climate warming in lakes in recent decades. In dimictic lakes, the subsequent periods of spring mixing and summer stratification are both likely to change in response to these phenological changes in ice cover. Here, we used a modeling approach to si...
Article
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The concentration of dissolved oxygen in aquatic systems helps to regulate biodiversity1,2, nutrient biogeochemistry3, greenhouse gas emissions4, and the quality of drinking water5. The long-term declines in dissolved oxygen concentrations in coastal and ocean waters have been linked to climate warming and human activity6,7, but little is known abo...
Article
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Wildfire smoke often covers areas larger than the burned area, yet the impacts of smoke on nearby aquatic ecosystems are understudied. In the summer of 2018, wildfire smoke covered Castle Lake (California, USA) for 55 days. We quantified the influence of smoke on the lake by comparing the physics, chemistry, productivity, and animal ecology in the...
Article
Full-text available
This assessment by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) provides the latest scientific update since our most recent comprehensive assessment (Photochemical and Photobiological Sciences, 2019, 18, 595–828). The interactive effects between the stratospheric ozone layer, solar ultraviolet...
Article
Alpine regions are changing rapidly due to loss of snow and ice in response to ongoing climate change. While studies have documented ecological responses in alpine lakes and streams to these changes, our ability to predict such outcomes is limited. We propose that the application of fundamental rules of life can help develop necessary predictive fr...
Chapter
Full-text available
This article examines the multiple roles that exposure to solar ultraviolet radiation (UV) plays in the structure and function of inland water ecosystems. The main concepts covered include factors controlling incident and underwater UV, the negative effects of UV on aquatic organisms and their corresponding defenses, and indirect effects including...
Chapter
Light is critical in structuring aquatic ecosystems. Sunlight used in photosynthesis provides the energy for the foundation of all but the simplest microbial communities in aquatic ecosystems. Seasonal variations in the heat energy provided by sunlight are responsible for thermal stratification and the mixing regimes of aquatic systems. This articl...
Article
Alpine regions are changing rapidly due to loss of snow and ice in response to ongoing climate change. While studies have documented ecological responses in alpine lakes and streams to these changes, our ability to predict such outcomes is limited. We propose that the application of fundamental rules of life can help develop necessary predictive fr...
Article
Full-text available
Outgassing of carbon dioxide (CO2) from freshwater ecosystems comprises 12 %–25 % of the total carbon flux from soils and bedrock. This CO2 is largely derived from both biodegradation and photodegradation of terrestrial dissolved organic carbon (DOC) entering lakes from wetlands and soils in the watersheds of lakes. In spite of the significance of...
Article
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Globally, lake surface water temperatures have warmed rapidly relative to air temperature, but changes in deepwater temperatures and vertical thermal structure are still largely unknown. We have compiled the most comprehensive data set to date of long-term (1970-2009) summertime vertical temperature profiles in lakes across the world to examine tre...
Article
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Mosquitoes have increased in their abundance and geographic distribution in northeastern North America, coinciding with an increase in extreme precipitation events and up to a doubling of dissolved organic matter (DOM) concentrations in some inland waters. Increases in DOM can reduce exposure of mosquito larvae to solar ultraviolet (UV) radiation....
Article
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Climate change is altering conditions in high-elevation streams worldwide, with largely unknown effects on resident communities of aquatic insects. Here, we review the challenges of climate change for high-elevation aquatic insects and how they may respond, focusing on current gaps in knowledge. Understanding current effects and predicting future i...
Article
Parasite fitness depends on a successful journey from one host to another. For parasites that are transmitted environmentally, abiotic conditions might modulate the success of this journey. Here we evaluate how light, a key abiotic factor, influences spatiotemporal patterns of zooplankton disease where light varies seasonally, across lakes, and wit...
Article
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Shifts in the composition of terrestrial plant communities could have significant effects on freshwater zooplankton due to changes in the quality of inputs of terrestrially derived dissolved organic matter (DOM). Leachate from native red maple (RM) and invasive Amur honeysuckle (AH) were used to explore the effects of DOM source on survival and gro...
Preprint
Full-text available
Outgassing of carbon dioxide (CO2) from freshwater ecosystems comprises 12–25 % of the total carbon flux from soils and bedrock. This CO2 is largely derived from both biodegradation and photodegradation of terrestrial dissolved organic carbon (DOC) entering lakes from wetlands and soils in the watersheds of lakes. In spite of the significance of th...
Article
Full-text available
Increases in dissolved organic matter and the consequent “browning” of some lakes in recent decades are reducing water transparency to both ultraviolet and photosynthetically active radiation with important, but poorly understood ecosystem-level consequences for zooplankton grazers. The prevailing resource-based unimodal hypothesis posits that nutr...
Article
This assessment, by the United Nations Environment Programme (UNEP) Environmental Effects Assessment Panel (EEAP), one of three Panels informing the Parties to the Montreal Protocol, provides an update, since our previous extensive assessment (Photochem. Photobiol. Sci., 2019, 18, 595–828), of recent findings of current and projected interactive en...
Article
Climate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to...
Article
Full-text available
In mountain lakes, water transparency is regulated primarily by materials loaded from the surrounding catchment. Consequently, transparency within a lake can vary over time due to meteorological conditions that affect hydrologic inputs. Furthermore, lake responses to these inputs may depend on catchment characteristics. We examined the relationship...
Preprint
Full-text available
Climate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to...
Article
Ozone depletion has altered conditions at the Earth’s surface and interacts with climate change. This Review assesses the effects on humans and ecosystems, including implications for food and water security, and the mitigating and ongoing influence of the Montreal Protocol.
Article
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of current knowledge about effects of UV radiation in inland and oceanic waters related to stratospheric ozone depletion and climate change.
Article
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In recent decades, terrestrial dissolved organic matter (DOM) has increased in many northeastern North American and European lakes and is contributing to long-term browning. We used a long-term dataset (1988–2014) to study the consequences of browning-related decreased water transparency on dissolved oxygen dynamics in 2 small temperate lakes in Pe...
Article
Surface water temperatures are warming in many lakes across the globe, and this is widely attributed to warming air temperatures. Yet two lakes in Pennsylvania (USA) have shown long-term increases in surface water temperatures over the past 27 summers during a period with no significant increase in regional air temperature. We examined the relation...
Article
Full-text available
The Environmental Effects Assessment Panel (EEAP) is one of three Panels of experts that inform the Parties to the Montreal Protocol. The EEAP focuses on the effects of UV radiation on human health, terrestrial and aquatic ecosystems, air quality, and materials, as well as on the interactive effects of UV radiation and global climate change. When c...
Article
Full-text available
Climate change is accelerating the release of dissolved organic matter (DOM) to inland and coastal waters through increases in precipitation, thawing of permafrost, and changes in vegetation. Our modeling approach suggests that the selective absorption of ultraviolet radiation (UV) by DOM decreases the valuable ecosystem service wherein sunlight in...
Article
We examined factors regulating water transparency in a set of 33 lakes located in the Canadian Rocky Mountains. Eighteen lakes had catchments that included glaciers and 15 did not. In each lake, we quantified midsummer attenuation rates for three ultraviolet wavelengths and photosynthetically active radiation and measured chromophoric dissolved org...
Article
Full-text available
Lake surface water temperatures are warming worldwide, raising concerns about the future integrity of valuable lake ecosystem services. In contrast to surface water temperatures, we know far less about what is happening to water temperature beneath the surface, where most organisms live. Moreover, we know little about which characteristics make lak...
Article
1. Dissolved organic matter (DOM) is increasing in many lakes due to climate change and other environmental forcing. A 21-day microcosm experiment that manipulated terrestrial DOM was used to determine the effect of DOM on zooplankton:phytoplankton biomass ratios (z:p). We predicted that if DOM additions increase the amount of fixed carbon availabl...
Article
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The use of high-frequency sensors on pro ling buoys to investigate physical, chemical, and biological processes in lakes is increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll uorescence (ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study...
Article
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Recent studies have demonstrated substantial effects of environmental stress that vary among clones. Exposure to ultraviolet radiation (UV) is an important abiotic stressor that is highly variable in aquatic ecosystems due to diel and seasonal variations in incident sunlight as well as to differences in the UV transparency of water among water bodi...
Article
We used a natural experiment to test whether wildfire smoke induced changes in the vertical distribution of zooplankton in Lake Tahoe by decreasing incident ultraviolet radiation (UV). Fires have a variety of effects on aquatic ecosystems, but these impacts are poorly understood and have rarely been observed directly. UV is an important driver of z...
Article
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Acoustic surveys of the distribution and abundance of freshwater zooplankton were conducted in Lake Giles, an oligotrophic freshwater lake. Volume backscatter data from a 710 kHz scientific echosounder were converted to high-resolution spatial and temporal numerical density estimates of small zooplankton. Vertical net tows of a 153 μm mesh closing...
Article
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Environmental drivers such as climate change are responsible for extreme events that are critically altering freshwater resources across the planet. In the continental US, these events range from increases in the frequency and duration of droughts and wildfires in the West, to increasing precipitation and floods that are turning lakes and reservoir...
Article
Binary choice experiments under natural solar radiation were used to test short-term behavioral responses of freshwater calanoid copepods to ultraviolet radiation (UV). Responses of the nine species from 15 populations spanning North and South America included both UV attraction and UV avoidance, and varied among habitats, species and populations....
Article
Full-text available
The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, biogeochemistry, air quality, and materials. The Panels provide a detail...
Article
Full-text available
Increases in terrestrially-derived dissolved organic matter (DOM) have led to the browning of inland waters across regions of northeastern North America and Europe. Short-term experimental and comparative studies highlight the important ecological consequences of browning. These range from transparency-induced increases in thermal stratification an...
Article
Full-text available
In this first worldwide synthesis of in situ and satellite-derived lake data, we find that lake summer surface water temperatures rose rapidly (global mean = 0.34°C decade−1) between 1985 and 2009. Our analyses show that surface water warming rates are dependent on combinations of climate and local characteristics, rather than just lake location, l...
Article
Predicting the effects of dissolved organic matter (DOM) on pelagic food webs can be difficult because DOM modifies water column optics and can have contrasting effects on species across trophic levels. We combined large mesocosm, smaller-scale experiments and autoregressive modeling driven bu DOC concentration or DOM optical quality (colored DOM,...
Article
Full-text available
Zooplankton diel vertical migration (DVM) is often explained as a balance between predator avoidance and resource acquisition. However, recent studies suggest that ultraviolet radiation (UV) may also be important in driving zooplankton DVM in some systems. Williamson et al. ( Williamson et al., 2011) proposed the “transparency-regulator hypothesis,...
Article
The effects of changes in chromophoric dissolved organic matter (CDOM) on zooplankton grazers in pelagic food webs can be difficult to predict due to the potential for conflicting direct and indirect effects of CDOM on water column optics and food-web dynamics. We compared the responses of two dominant zooplankton groups, Daphnia spp. and calanoid...
Article
Ecosystems are subsidized with inputs of mass and energy from their surroundings. These allochthonous inputs regulate many ecosystem characteristics. In inland waters, terrestrial inputs of organic matter regulate food-web structure, ecosystem metabolism, water clarity, and thermal stratification. Future changes in allochthony may be especially pro...
Article
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Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...
Article
Full-text available
Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...
Conference Paper
Long term trends and variability in the seasonality of lake ice dynamics are some of the clearest indicators of changes in climate conditions. The timing of ice formation, ice cover duration and ice loss in lakes and reservoirs will modulate the impact of regional weather conditions on lake thermal structure and mixing, and thus will ultimately inf...
Article
Full-text available
Preface The assessments presented in the seven papers published in this journal deal with the effects of ozone depletion on human health and the environment and the consequences of interactions between ozone depletion and global climate change. This report is produced in the first instance as a limited edition for governments, via the United Nation...
Article
Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends...
Article
The transparency regulator hypothesis (TRH) proposes that water transparency determines the relative importance of visual predation vs. ultraviolet radiation (UVR) in driving zooplankton out of the surface waters during the day. To test this hypothesis, we used a combination of observational and experimental approaches to examine the effects of UVR...
Article
Full-text available
Interactions between climate change and UV radiation are having strong effects on aquatic ecosystems due to feedback between temperature, UV radiation, and greenhouse gas concentration. Higher air temperatures and incoming solar radiation are increasing the surface water temperatures of lakes and oceans, with many large lakes warming at twice the r...
Article
Transparency is a fundamental characteristic of aquatic ecosystems and is highly responsive to changes in climate and land use. The transparency of glacially-fed lakes may be a particularly sensitive sentinel characteristic of these changes. However, little is known about the relative contributions of glacial flour versus other factors affecting li...
Article
Full-text available
The projected large increases in damaging ultraviolet radiation as a result of global emissions of ozone-depleting substances have been forestalled by the success of the Montreal Protocol. New challenges are now arising in relation to climate change. We highlight the complex interactions between the drivers of climate change and those of stratosphe...
Article
As the lowest point in the surrounding landscape, lakes act as sensors in the landscape to provide insights into the response of both terrestrial and aquatic ecosystems to climate change. Here a novel suite of climate forcing optical indices (CFOI) from lakes across North America is found to respond to changes in air temperature, precipitation, and...
Article
In clear, cold-water lakes, ultraviolet radiation (UV) and temperature are two important stressors that may prevent the establishment of aquatic invasive species by inhibiting the survival of sensitive early life history stages. In this study, we develop a UV–temperature response model to predict the establishment potential of a warmwater fish, lar...
Article
Full-text available
Although the best known cases of enigmatic amphibian population declines come from mountains, the broader relationship between declines and elevation has not been well examined. We analyzed data from the Global Amphibian Assessment (GAA) and minimum and maximum elevation range data to study the association between elevation and population status fo...
Article
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Recent climate-change research largely confirms the impacts on US ecosystems identified in the 2009 National Climate Assessment and provides greater mechanistic understanding and geographic specificity for those impacts. Pervasive climate-change impacts on ecosystems are those that affect productivity of ecosystems or their ability to process chemi...
Article
Full-text available
Inputs of terrestrially derived dissolved organic matter (DOM) are increasing in alpine lakes due to multiple drivers such as climate change, tree line advancement, and insect epidemics. A 21 d microcosm experiment investigated three potential mechanisms by which increased inputs of terrestrial DOM subsidies might affect phytoplankton density, grow...