Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Animals (2)
- Zooplankton (2)
- Angiospermae (1)
- Bacteria (1)
- Basic reproduction number (1)
-
- Bioeconomic model (1)
- Bioeconomics (1)
- Biomass (1)
- Carbon dioxide flux (1)
- Chemical (1)
- Chloride (1)
- Chlorophyll (1)
- Communicable diseases (1)
- Computer simulation (1)
- Culicidae (1)
- Daphnia (1)
- Dicotyledones (1)
- Dispersal (1)
- Dispersion (1)
- Dna (1)
- Dynamic optimization (1)
- Dynamics (1)
- East and west long lakes (1)
- Ecosystem services (1)
- Environmental monitoring (1)
- Environmental protection (1)
- Eutrophication (1)
- Fish (1)
- Food chain (1)
- Food web (1)
Articles 1 - 9 of 9
Full-Text Articles in Biology
Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley
Salting Our Freshwater Lakes, Hilary A. Dugan, Sarah L. Bartlett, Samantha M. Burke, Jonathan P. Doubek, Flora Krivak-Tetley
Dartmouth Scholarship
The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a …
Predicting Landscape-Scale Co 2 Flux At A Pasture And Rice Paddy With Long-Term Hyperspectral Canopy Reflectance Measurements, J. H. Matthes, S. H. Knox, C. Sturtevant, O. Sonnentag
Predicting Landscape-Scale Co 2 Flux At A Pasture And Rice Paddy With Long-Term Hyperspectral Canopy Reflectance Measurements, J. H. Matthes, S. H. Knox, C. Sturtevant, O. Sonnentag
Dartmouth Scholarship
Measurements of hyperspectral canopy reflectance provide a detailed snapshot of information regarding canopy biochemistry, structure and physiology. In this study, we collected 5 years of repeated canopy hyperspectral reflectance measurements for a total of over 100 site visits within the flux footprints of two eddy covariance towers at a pasture and rice paddy in northern California. The vegetation at both sites exhibited dynamic phenology, with significant interannual variability in the timing of seasonal patterns that propagated into interannual variability in measured hyperspectral reflectance. We used partial least-squares regression (PLSR) modeling to leverage the information contained within the entire canopy reflectance …
Spatial Heterogeneity, Host Movement And Mosquito-Borne Disease Transmission, Miguel A. Acevedo, Olivia Prosper, Kenneth Lopiano, Nick Ruktanonchai, T. Trevor Caughlin, Maia Martcheva, Craig W. Osenberg, David L. Smith
Spatial Heterogeneity, Host Movement And Mosquito-Borne Disease Transmission, Miguel A. Acevedo, Olivia Prosper, Kenneth Lopiano, Nick Ruktanonchai, T. Trevor Caughlin, Maia Martcheva, Craig W. Osenberg, David L. Smith
Dartmouth Scholarship
Mosquito-borne diseases are a global health priority disproportionately affecting low-income populations in tropical and sub-tropical countries. These pathogens live in mosquitoes and hosts that interact in spatially heterogeneous environments where hosts move between regions of varying transmission intensity. Although there is increasing interest in the implications of spatial processes for mosquito-borne disease dynamics, most of our understanding derives from models that assume spatially homogeneous transmission. Spatial variation in contact rates can influence transmission and the risk of epidemics, yet the interaction between spatial heterogeneity and movement of hosts remains relatively unexplored. Here we explore, analytically and through numerical simulations, how …
Using Economic Instruments To Develop Effective Management Of Invasive Species: Insights From A Bioeconomic Model, Shana M. Mcdermott, Rebecca E. Irwin, Brad W. Taylor
Using Economic Instruments To Develop Effective Management Of Invasive Species: Insights From A Bioeconomic Model, Shana M. Mcdermott, Rebecca E. Irwin, Brad W. Taylor
Dartmouth Scholarship
Economic growth is recognized as an important factor associated with species invasions. Consequently, there is increasing need to develop solutions that combine economics and ecology to inform invasive species management. We developed a model combining economic, ecological, and sociological factors to assess the degree to which economic policies can be used to control invasive plants. Because invasive plants often spread across numerous properties, we explored whether property owners should manage invaders cooperatively as a group by incorporating the negative effects of invader spread in management decisions (collective management) or independently, whereby the negative effects of invasive plant spread are ignored …
Knowing When To Draw The Line: Designing More Informative Ecological Experiments, Kathryn L. Cottingham, Jay T. Lennon, Bryan L. Brown
Knowing When To Draw The Line: Designing More Informative Ecological Experiments, Kathryn L. Cottingham, Jay T. Lennon, Bryan L. Brown
Dartmouth Scholarship
Linear regression and analysis of variance (ANOVA) are two of the most widely used statistical techniques in ecology. Regression quantitatively describes the relationship between a response variable and one or more continuous independent variables, while ANOVA determines whether a response variable differs among discrete values of the independent variable(s). Designing experiments with discrete factors is straightforward because ANOVA is the only option, but what is the best way to design experiments involving continuous factors? Should ecologists prefer experiments with few treatments and many replicates analyzed with ANOVA, or experiments with many treatments and few replicates per treatment analyzed with regression? …
Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum
Algal Blooms Reduce The Uptake Of Toxic Methylmercury In Freshwater Food Webs, Paul C. Pickhardt, Carol L. Folt, Celia Y. Chen, Bjoern Klaue, Joel D. Blum
Dartmouth Scholarship
Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener, eutrophic lakes often carry less mercury. In this study, we experimentally tested the hypothesis that increasing algal biomass reduces mercury accumulation at higher trophic levels through the dilution of mercury in consumed algal cells. Under bloom dilution, as algal biomass …
Trophic Cascades, Nutrients, And Lake Productivity: Whole-Lake Experiments, Stephen R. Carpenter, Jonathan J. Cole, James R. Hodgson, James F. Kitchell, Michael L. Pace, Darren Bade, Kathryn L. Cottingham
Trophic Cascades, Nutrients, And Lake Productivity: Whole-Lake Experiments, Stephen R. Carpenter, Jonathan J. Cole, James R. Hodgson, James F. Kitchell, Michael L. Pace, Darren Bade, Kathryn L. Cottingham
Dartmouth Scholarship
Responses of zooplankton, pelagic primary producers, planktonic bacteria, and CO2 exchange with the atmosphere were measured in four lakes with contrasting food webs under a range of nutrient enrichments during a seven-year period. Prior to enrichment, food webs were manipulated to create contrasts between piscivore dominance and planktivore dominance. Nutrient enrichments of inorganic nitrogen and phosphorus exhibited ratios of N:P > 17:1, by atoms, to maintain P limitation. An unmanipulated reference lake, Paul Lake, revealed baseline variability but showed no trends that could confound the interpretation of changes in the nearby manipulated lakes. Herbivorous zooplankton of West Long Lake (piscivorous fishes) …
Evidence For Helical Structures In Poly(1-Olefin Sulfones) By Transmission Electron Microscopy, George C. Ruben, W H. Stockmayer
Evidence For Helical Structures In Poly(1-Olefin Sulfones) By Transmission Electron Microscopy, George C. Ruben, W H. Stockmayer
Dartmouth Scholarship
Transmission electron microscope images were obtained of fractions of poly(1-tetradecene sulfone) and poly(cyclohexene sulfone) cast from very dilute solutions (0.007%, wt/vol) and rapidly freeze-dried on a mica surface. The samples were then vertically platinum-carbon (Pt-C) replicated with 9 +/- 0.3-A Pt-C and held together with 128 A of electron-transparent evaporated carbon. The Pt-C coating enlarges the molecular chain diameters by approximately 5 A, so that a single polysulfone chain has an apparent diameter of 9-12 A in the transmission electron microscope. Poly(1-tetradecene sulfone) forms short helical regions that show irregular helical turns of pitch 7-18 A, two to eight turns …
A Dna Sequence Analysis Program For The Apple Macintosh, Robert H. Gross
A Dna Sequence Analysis Program For The Apple Macintosh, Robert H. Gross
Dartmouth Scholarship
This paper describes a new set of programs * for analyzing DNA sequences using the Apple Macintosh computer, a computer ideally suited for this kind of analysis. Because of the Macintosh interface and the availability of high quality software-only speech synthesis, these programs are truly easy to use. Instead of typing in commands, the user directs the program by making selections with the mouse, thereby eliminating most typographical and syntax errors. Output options are selected by “pressing buttons” and then clicking “OK” with the mouse. DNA sequences are confirmed by having the program speak them. The high resolution graphics on …