Stephen K Hamilton

Stephen K Hamilton
Michigan State University | MSU · W. K. Kellogg Biological Station

PhD

About

277
Publications
75,527
Reads
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20,565
Citations
Citations since 2017
82 Research Items
9460 Citations
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201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
Additional affiliations
August 1995 - present
Michigan State University
Position
  • Professor (Full)

Publications

Publications (277)
Article
Full-text available
Leaf photosynthesis of perennial grasses usually decreases markedly from early to late summer, even when the canopy remains green and environmental conditions are favorable for photosynthesis. Understanding the physiological basis of this photosynthetic decline reveals the potential for yield improvement. We tested the association of seasonal photo...
Article
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Without fertilization, harvest of perennial bioenergy cropping systems diminishes soil nutrient stocks, yet the time course of nutrient drawdown has not often been investigated. We analyzed phosphorus (P) inputs (fertilization and atmospheric deposition) and outputs (harvest and leaching losses) over seven years in three representative biomass crop...
Article
The Amazon River basin harbors some of the world's largest wetland complexes, which are of major importance for biodiversity, the water cycle and climate, and human activities. Accurate estimates of inundation extent and its variations across spatial and temporal scales are therefore fundamental to understand and manage the basin's resources. More...
Article
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Meeting end-of-century global warming targets requires aggressive action on multiple fronts. Recent reports note the futility of addressing mitigation goals without fully engaging the agricultural sector, yet no available assessments combine both nature-based solutions (reforestation, grassland and wetland protection, and agricultural practice chan...
Article
Full-text available
All animals carry specialized microbiomes, and their gut microbiota are continuously released into the environment through excretion of waste. Here we propose the meta-gut as a novel conceptual framework that addresses the ability of the gut microbiome released from an animal to function outside the host and alter biogeochemical processes mediated...
Article
Numerous hydropower facilities are under construction or planned in tropical and subtropical rivers worldwide. While dams are typically designed considering historic river discharge regimes, climate change is likely to induce large-scale alterations in river hydrology. Here we analyze how future climate change will affect river hydrology, electrici...
Article
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Animals can impact freshwater ecosystem structure and function in ways that persist well beyond the animal’s active presence. These legacy effects can last for months, even decades, and often increase spatial and temporal heterogeneity within a system. Herein, we review examples of structural, biogeochemical, and trophic legacies from animals in st...
Article
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Excessive phosphorus (P) applications to croplands can contribute to eutrophication of surface waters through surface runoff and subsurface (leaching) losses. We analyzed leaching losses of total dissolved P (TDP) from no-till corn, hybrid poplar (Populus nigra X P. maximowiczii), switchgrass (Panicum virgatum), miscanthus (Miscanthus giganteus), n...
Article
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Climate benefit assessments of bioenergy crops often focus on biogeochemical impacts, paying little if any attention to biogeophysical impacts. However, land conversions required for large-scale bioenergy crop production are substantial and may directly affect the climate by altering surface energy balance. In the US, such land conversions are like...
Article
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Abstract Biofuel crops, including annuals such as maize (Zea mays L.), soybean [Glycine max (L.) Merr.], and canola (Brassica napus L.), as well as high‐biomass perennial grasses such as miscanthus (Miscanthus × giganteus J.M. Greef & Deuter ex Hodkinson & Renvoiz), are candidates for sustainable alternative energy sources. However, large‐scale con...
Article
A Richards-based soil water model was implemented in the APEX and EPIC terrestrial ecosystem models to improve their hydrologic modeling capabilities. The Richards model together with two existing soil water models were calibrated and evaluated to assess their performance for simulating watershed-level hydrology under scenarios of landscape convers...
Article
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• The shells of freshwater molluscs are highly plastic in response to environmental and ecological conditions, which can affect ecological interactions and ecosystem functioning. • We tested for changes in relative shell thickness in the unionid bivalve Elliptio complanata in the freshwater tidal Hudson River over 1991–2017, a period of changing wa...
Article
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Ecosystems across the United States are changing in complex and unpredictable ways and analysis of these changes requires coordinated, long-term research. This paper is a product of a synthesis effort of the U.S. National Science Foundation funded Long-Term Ecological Research (LTER) network addressing the LTER core research area of “populations an...
Preprint
Full-text available
All animals carry specialized microbiomes, and their gut microbiotas in particular are continuously released into the environment through excretion of waste. Here we propose the meta-gut as a novel conceptual framework that addresses the ability of the gut microbiome released from an animal to function outside the host and potentially alter ecosyst...
Article
Full-text available
Hydroelectric facilities often release water at variable rates over the day to match electricity demand, resulting in short-term variability in downstream discharge and water levels. This sub-daily variability, known as hydropeaking, has mostly been studied at large facilities. The ongoing global proliferation of small hydropower (SHP) facilities,...
Article
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Hippopotami (hippos) are ecosystem engineers that subsidize aquatic ecosystems through the transfer of organic matter and nutrients from their terrestrial grazing, with potentially profound effects on aquatic biogeochemistry. We examined the influence of hippo subsidies on biogeochemical cycling in pools of varying hydrology and intensity of hippo...
Article
Small hydroelectric power (SHP) facilities are proliferating around the world, including in Brazil where legislation encourages SHP over other hydropower development, defining SHP as facilities with installed capacities of 3–30 MW and reservoirs <13 km². SHP facilities are often diversion designs with small or no reservoirs, while other SHPs have m...
Chapter
This chapter briefly presents the most important microbially mediated redox reactions in ecosystems. The chapter introduces redox reactions and their terminology, electron donors and acceptors, and energy yields from redox reactions. It then describes some of the most important microbially mediated redox reactions and the environments in which each...
Article
Full-text available
Small hydropower (SHP) facilities, defined variably but usually by installed capacities of <10–50 MW, are proliferating around the world, particularly in tropical and subtropical regions. Compared to larger dams, SHPs are generally viewed as having less environmental impact, although there has been little research to support that assertion. Numerou...
Article
Full-text available
Small hydropower (SHP) facilities, which are defined by installed capacities <10-50 MW, are increasingly being built around the world. SHPs are viewed as less environmentally harmful than larger dams, although there has been little research to support that assertion. Numerous SHPs have been built, and many more are in development or proposed, in ri...
Article
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Assessment of inundation patterns across large and remote floodplains is challenging and costly. Inexpensive loggers that record the damping of the diel amplitude of temperature (DAT) when submerged compared to overlying air can indirectly indicate inundation. We assessed the efficacy of this approach in tropical, subtropical, and temperate floodpl...
Article
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Large storage dams have widely documented impacts on downstream aquatic environments, but hydroelectric dams with little or no capacity for storage of water inflows (i.e., run-of-river) have received less attention. Two of the world's largest run-of-river hydropower dams (Jirau and Santo Antônio, Brazil) are located on the Madeira River, the larges...
Article
Understanding the movement and storage of water within agricultural landscapes as functions of management and climate is essential for more efficient and sustainable water use. However, knowledge of water storage and fluxes on U.S. agricultural lands is largely incomplete. The Long-Term Agroecosystem Research (LTAR) network provides a unique and ge...
Article
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Pathogens and parasites (henceforth “pathogens”) can make up a large percentage of the biomass found in ecosystems, and therefore, their impacts on ecosystem processes should be prominent. Pathogens influence ecosystem processes by affecting the abundance or phenotype of hosts and through direct contributions to ecosystem production. However, there...
Article
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Leaching losses of dissolved organic carbon (DOC) and nitrogen (DON) from agricultural systems are important to water quality and carbon and nutrient balances but are rarely reported; the few available studies suggest linkages to litter production (DOC) and nitrogen fertilization (DON). In this study we examine the leaching of DOC, DON, NO3⁻, and N...
Article
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Climate mitigation scenarios limiting global temperature increases to 1.5 °C rely on decarbonizing vehicle transport with bioenergy production plus carbon capture and storage (BECCS), but climate impacts for producing different bioenergy feedstocks have not been directly compared experimentally or for ethanol vs electric light-duty vehicles. A fiel...
Article
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There are 104 hydroelectric facilities proposed to be installed in the watersheds that feed the Pantanal, a vast floodplain wetland located mostly in Brazil. The Pantanal is host to 23 long‐distance migratory fish species that ascend upland tributaries to spawn. A Geographic Information System was used to predict the impact of hydroelectric dams on...
Article
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We used a 27‐year record of Dreissena populations in the freshwater tidal Hudson River to describe interannual variation in population density, body size, and body condition; estimate long‐term variation in recruitment, survivorship, and shell growth; and assess possible controls on the populations. Dreissena populations in the Hudson have been hig...
Article
Full-text available
Run-of-river dams are often considered to have lower environmental impacts than storage dams due to their smaller reservoirs and low potential for flow alteration. However, this has been questioned for projects recently built on large rivers around the world. Two of the world’s largest run-of-river dams—Santo Antônio and Jirau—were recently constru...
Article
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Perennial cellulosic crops are promoted for their potential contributions to a sustainable energy future. However, large‐scale perennial bioenergy production requires extensive land use changes through diversion of croplands or conversion of uncultivated lands, with potential implications for local and regional hydrology. To assess the impact of su...
Article
Stream temperature controls biological processes and affects the species composition of aquatic communities. Riparian vegetation plays an important role in influencing stream temperatures due to vegetation shading and by changing the riparian microclimate (wind speed, relative humidity, etc). This paper explores the effects of spatial heterogeneity...
Article
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Hundreds of dams have been proposed throughout the Amazon basin, one of the world's largest untapped hydropower frontiers. While hydropower is a potentially clean source of renewable energy, some projects produce high greenhouse gas (GHG) emissions per unit electricity generated (carbon intensity). Here we show how carbon intensities of proposed Am...
Article
Systematic conservation planning has contributed to the spatial design of reserve networks in river ecosystems by recognizing the importance of maintaining longitudinal connectivity. In the complex and dynamic landscapes of river-floodplain systems, however, it is still challenging to account for the longitudinal and, especially, lateral connection...
Article
This study examined evapotranspiration (ET) from no-till, rainfed maize and soybean during three growing seasons (May-Sep) of normal rainfall years (2009, 2010, 2011) and a drought year (2012) in Michigan, USA, based on daily soil water uptake measured by time-domain reflectometry at multiple depths through the root zone. During normal rainfall yea...
Article
Full-text available
Calcium (Ca) is an essential element for almost all living organisms. Here, we examined global variation and controls of freshwater Ca concentrations, using 440 599 water samples from 43 184 inland water sites in 57 countries. We found that the global median Ca concentration was 4.0 mg L−1 with 20.7% of the water samples showing Ca concentrations ≤...
Data
Supplementary Material: Carbon debt of field-scale conservation reserve program grasslands converted to annual and perennial bioenergy crops. Environ. Res. Lett. 14 024019
Article
Full-text available
In the upper Paraguay River basin, which includes the Pantanal, one of the largest wetlands in the world, rivers connection the surrounding upland plateaus with lowland floodplains. Agriculture, erosion, urban effluent, and hydropower in the uplands can alter the transport of materials by rivers to the Pantanal. Information about material transport...
Article
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Over 5 million ha of US Conservation Reserve Program (CRP) grasslands have been converted to annual crops since 2000, driven mainly by demand for corn grain ethanol. Much of the soil carbon sequestered under CRP is lost upon conversion, creating a 'carbon debt' that is presumed to be repaid by future greenhouse gas (GHG) savings from ethanol's subs...
Article
• In many wetlands the timing and duration of inundation determine ecological characteristics and the provision of ecosystem services; however, wetland conservation decisions often rely on static maps of wetland boundaries that do not capture their dynamic hydrological variability and connectivity. • The Amazon River basin contains some of the worl...
Article
Full-text available
Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled huma...
Data
Description The data in this file are collected from field experiments at the W.K. Kellogg Biological Station (KBS) Long-Term Ecological Research (LTER) site of the Michigan State University. The file contains annual CO2-equivalent balances of net ecosystem C exchange (measured using eddy covariance), N2O and CH4 fluxes (measured using chamber meth...
Article
Full-text available
We use a 32-year dataset from a rural, southeastern New York stream to describe the effect of long-term road salt use on concentrations of sodium (Na⁺) and chloride (Cl⁻). Mean annual stream Na⁺ and Cl⁻ concentrations initially increased, reached a plateau, and then increased again. Trends in summer and winter stream concentrations were similar but...
Article
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Globally, the proportion of total rainfall occurring as extreme events is increasing, which may have consequences for agriculture. In the US Midwest, we conducted a 234-d manipulative experiment in 16 paired plots where we increased the proportion of rain falling in extreme events on tilled and no-till cropping systems. We compared the effects of l...
Article
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A multitude of biologically active pharmaceuticals contaminate surface waters globally, yet their presence in aquatic food webs remain largely unknown. Here, we show that over 60 pharmaceutical compounds can be detected in aquatic invertebrates and riparian spiders in six streams near Melbourne, Australia. Similar concentrations in aquatic inverteb...
Article
Full-text available
Perennial grasses can assimilate nitrogen (N) fixed by non-nodulating bacteria living in the rhizosphere and the plant's own tissues, but many details of associative N fixation (ANF) remain unknown, including ANF's contribution to grass N nutrition, the exact location of fixation, and composition of the associated microbial community. We examined A...
Article
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Groundwater irrigation of cropland is expanding worldwide with poorly known implications for climate change. This study compares experimental measurements of the net global warming impact of a rainfed vs. a groundwater‐irrigated corn (maize)‐soybean‐wheat, no‐till cropping system in the Midwest US, the region that produces the majority of US corn a...
Article
Full-text available
Land use conversions into and out of agriculture may influence soil–atmosphere greenhouse gas fluxes for many years. We tested the legacy effects of land use on cumulative soil nitrous oxide (N2O) fluxes for 5 yr following conversion of 22‐yr‐old Conservation Reserve Program (CRP) grasslands and conventionally tilled agricultural fields (AGR) to co...
Data
The data includes short-term carbon mineralization rates (0-10 cm; 2009 and 2014), and annual and cumulative soil nitrous oxide (N2O-N) fluxes (2010 through 2014) for no-till continuous corn, switchgrass and restored prairie systems. Fields were converted from Conservation Reserve program (CRP) grasslands and/or conventionally tilled corn-soybean r...
Article
Full-text available
Organic matter and nutrient loading into aquatic ecosystems affects ecosystem structure and function and can result in eutrophication and hypoxia. Hypoxia is often attributed to anthropogenic pollution and is not common in unpolluted rivers. Here we show that organic matter loading from hippopotami causes the repeated occurrence of hypoxia in the M...
Article
Full-text available
Bicarbonate (HCO3−), the predominant form of dissolved inorganic carbon in natural waters, originates mostly from watershed mineral weathering. On time scales of decades to centuries, riverine fluxes of HCO3− to the oceans and subsequent reactions affect atmospheric CO2, global climate and ocean pH. This review summarizes controls on the production...
Article
Full-text available
Land use changes into and out of agricultural production may substantially influence ecosystem carbon (C) balance for many years. We examined ecosystem C balances for eight years after the conversion of 22 year-old Conservation Reserve Program (CRP) grasslands and formerly tilled agricultural fields (AGR) to annual (con-tinuous no-till corn) and pe...
Data
Annual net ecosystem C exchange (NEE) measured using eddy covariance, annual C harvested in biomass, and annual and cumulative NEEadj (NEE adjusted for C in harvest) for no-till continuous corn systems and perennial croplands (monoculture switchgrass and restored native prairie) converted from Conservation Reserve Program (CRP) grasslands and conve...
Article
Full-text available
In temperate humid catchments, evapotranspiration returns more than half of the annual precipitation to the atmosphere, thereby determining the balance available to recharge groundwaters and support stream flow and lake levels. Changes in evapotranspiration rates and therefore catchment hydrology could be driven by changes in land use or climate. H...
Article
Full-text available
Background Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across br...