A5047983599- Soil and Water Nutrient Dynamics
- Marine and coastal ecosystems
- Fish Ecology and Management Studies
- Coastal wetland ecosystem dynamics
- Freshwater macroinvertebrate diversity and ecology
- Microbial Community Ecology and Physiology
- Aquatic Ecosystems and Phytoplankton Dynamics
- Aquatic Invertebrate Ecology and Behavior
- Marine Biology and Ecology Research
- Wastewater Treatment and Nitrogen Removal
- Peatlands and Wetlands Ecology
- Hydrology and Watershed Management Studies
- Marine and coastal plant biology
- Isotope Analysis in Ecology
- Wildlife-Road Interactions and Conservation
- Urban Stormwater Management Solutions
- Smart Materials for Construction
- Hydrology and Sediment Transport Processes
- Land Use and Ecosystem Services
- Plant responses to elevated CO2
- Environmental DNA in Biodiversity Studies
- Water Quality and Pollution Assessment
- Groundwater and Isotope Geochemistry
- Constructed Wetlands for Wastewater Treatment
- Ecology and Conservation Studies
Cary Institute of Ecosystem Studies
2011-2021
Ecological Society of America
2016-2020
John Wiley & Sons (United States)
2016-2020
IFC Research (United Kingdom)
2018-2019
Wyoming Game and Fish Department
2019
University of Maryland Center for Environmental Science
2008
US Forest Service
2008
Dutchess Community College
2007
Experimental Station
2005
University of Wisconsin–Oshkosh
2005
Heterotrophic bacteria are thought to be important components of aquatic ecosystems in several ways.These remineralize organic materials and convert some material into bacterial biomass.We examined data from 70 studies which estimates production heterotrophic biomass (bacterial production) were reported for fresh-and saltwater ecosystems.In sediments, was sigdicantly (p <0.001), positively correlated sediment C content.Systems had hlgh rates benthic primary (such as coral reefs) greater than...
▪ Abstract The hyporheic zone is an active ecotone between the surface stream and groundwater. Exchanges of water, nutrients, organic matter occur in response to variations discharge bed topography porosity. Upwelling subsurface water supplies organisms with nutrients while downwelling provides dissolved oxygen microbes invertebrates zone. Dynamic gradients exist at all scales vary temporally. At microscale, redox potential control chemical microbially mediated nutrient transformations...
In many streams, significant amounts of water are exchanged between saturated sediments surrounding the open channel (the hyporheic zone) and itself. Such exchanges with zone have potential to cause large changes in streamwater chemistry because rates biogeochemical processes actual types (e.g. anaerobic vs. aerobic metabolism) may be fundamentally different. I propose an organizational scheme for grouping stream systems into clusters minimal, moderate, maximal contribution metabolism...
B ivalves (clams and mussels) are among the most familiar of aquatic organisms. Many have been used by humans for centuries as important sources food ornament, some species economically pests, fouling water intakes other structures. It is only recently, however, that ecologists begun to understand bivalves also play many roles in ecosystems (e.g., Dame 1996). The functional importance bivalves, especially fresh water, still not fully appreciated. For example, recent ecology I textbooks...
Changes in the biomass of benthic bivalves can cause dramatic changes total grazing pressure aquatic systems, but few studies document ecosystem-level impacts these changes. This study documents a massive decline phytoplankton concurrent with invasion an exotic bivalve, zebra mussel (Dreissena polymorpha), and demonstrates that actually caused this decline. In fall 1992 became established at high Hudson River Estuary, mussels remained during 1993 1994. During 2 yr, on was over 10-fold...
A better understanding is needed of how hydrological and biogeochemical processes control dissolved organic carbon (DOC) concentrations matter (DOM) composition from headwaters downstream to large rivers. We examined a DOM dataset the National Water Information System US Geological Survey, which represents approximately 100 000 measurements DOC concentration at many sites along rivers across United States. Application quantile regression revealed tendency towards spatial temporal...
Sodium and chloride concentrations export increased from 1986 to 2005 in a rural stream southeastern New York. Concentrations 1.5 mg/L per year (chloride) 0.9 (sodium), 33 000 kg/year 20 (sodium) during this period. We estimate that salt used for deicing accounted 91% of the sodium input watershed, while sewage water softeners less than 10% input. Road use watershed did not increase study, but is likely have slightly due small population. Increased cannot account concentration watershed....
Freshwater shore zones are among the most ecologically valuable parts of planet, but have been heavily damaged by human activities. Because management and rehabilitation freshwater could be improved better use ecological knowledge, we summarize here what is known about their functioning. Shore complexes habitats that support high biodiversity, which enhanced physical complexity connectivity. dissipate large amounts energy, can receive process extraordinarily inputs autochthonous...
Summary 1. The Lotic Intersite Nitrogen eXperiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective to relate inter‐biome variability physical, chemical biological processes. 2. Data were collected from 11 streams ranging arctic tropical desert rainforest. Measurements at each site included hydraulic characteristics, parameters, whole‐stream metabolism uptake. Ammonium measured by injection 15...
The temporal dynamics and spatial distributions of zooplankton in the tidal freshwater portion Hudson River were studied over a 3-yr period. We tested hypothesis that advective transport regulates biomass lakes, estuaries, rivers for which we have published values. In Hudson, was negatively correlated with discharge entire season (P < 0.0001) as well during warmer period year = 0.007) when greatest. distribution 160-km transects heterogeneous. Downstream changes abundance dominant...
We investigated regional effects of urbanization and land use change on nitrate concentrations in approximately 1,000 small streams Maryland during record drought wet years 2001−2003. also changes nitrate-N export the same time period 8 intensively monitored watersheds across an gradient Baltimore, Maryland. Nitrate-N were greatest agricultural streams, urban forest respectively. During years, exports Baltimore showed substantial variation 6 suburban/urban (2.9−15.3 kg/ha/y), 1 stream...
Approximately 50% of streamwater dissolved organic C (DOC) disappeared from interstitial water moving along a hyporheic flowpath below gravel bar. Concurrent decreases in oxygen and increases inorganic (DIC) indicate metabolism streamwater‐derived DOC by microbes. Loss 100 µ M would account for 24–39% the depletion DIC accumulation. Sediments were incubated with collected stream channel two wells to examine whether could support growth sedimentary bacteria. Streamwater upstream end...
Bacterial abundances, biomass, and production were measured over a 3‐yr period at stations along 158‐km reach of the tidal, freshwater Hudson River. abundances ranged from 1 to 10 × 6 cells ml −1 with maximal values in summer. Abundance averaged all for ice‐free season (April through December) 4.9 9.1 9 liter d , respectively, both significantly correlated temperature. Neither bacterial abundance nor showed significant spatial variability study reach. In contrast results many autotrophic...
Hyporheic sediment bacterial communities were exposed to dissolved organic matter (DOM) from a variety of sources assess the interdependence metabolism and community composition. Experiments ranged small‐scale core perfusions with defined compounds (glucose, bovine serum albumin) mesocosms receiving natural leaf leachate or water different streams. Response variables included production, oxygen consumption, extracellular enzyme activity, similarity as manifest by changes in banding patterns...
We examined the fate of planktonic bacterial production and balance between growth grazing mortality in surface waters Upton Lake, New York. Growth rates were measured by incorporation [3H]thymidine into DNA. Grazing on bacteria determined with small cells produced a mutant strain Escherichia coli made either fluorescent or radioactive to monitor feeding. Bacterial community turnover times calculated from ranged 1.5 16 d. On basis these data results 29 other studies, most communities appear...
We measured denitrification rates using a field 15 NO 3 − tracer‐addition approach in large, cross‐site study of nitrate uptake reference, agricultural, and suburban‐urban streams. 49 72 streams studied. Uptake length due to ( S Wden n) ranged from 89 m 184 km (median 9050 m) there were no significant differences among regions or land‐use categories, likely because the wide range conditions within each region land use. N 2 production far exceeded O all The fraction total removal water 0.5%...
Microbes play numerous roles in stream ecosystems. They carry out key processes nutrient cycles and are responsible for a large part of organic matter breakdown. Advances over the past 25 y our understanding which microbes linked to specific have been rapid fundamental, part, because improvements methods. It is now clear that immobilization inorganic nutrients other transformations just as important release during decomposition. Microbial biomass recognized portion trophic transfer, but...
There has been a long-term decline in nitrate (NO3−) concentration and export from several monitoring watersheds New England that cannot be explained by current terrestrial ecosystem models. A number of potential causes for this nitrogen (N) have suggested, including changes atmospheric chemistry, insect outbreaks, soil frost, interannual climate fluctuations. In-stream removal NO3− not included attempts to explain regional watershed export, yet streams may high rates NO3−. We make use 40...
The impact of organisms on oxygen is one the most dramatic examples ecosystem engineering Earth. In aquatic systems, which have much lower concentrations than atmosphere, vascular plants can affect significantly not only long time scales but also less a day. Aquatic are generally thought as adding to systems through photosynthesis, varies greatly with plant morphology. Floating-leaved that vent atmosphere strongly deplete oxygen. some ecosystems where floating-leaved replaced submersed...