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Full-Text Articles in Ecology and Evolutionary Biology

Short-Term Versus Long-Term Effects Of Nitrogen Addition And Warming On Ecosystem N Dynamics In A Grass-Dominated Temperate Old Field, Benjamin F. A. Souriol Oct 2023

Short-Term Versus Long-Term Effects Of Nitrogen Addition And Warming On Ecosystem N Dynamics In A Grass-Dominated Temperate Old Field, Benjamin F. A. Souriol

Electronic Thesis and Dissertation Repository

Increased atmospheric nitrogen (N) deposition and climate warming are both anticipated to influence the ecosystem N dynamics of northern temperate ecosystems substantially over the next century. Nevertheless, in field experiments with N addition and warming treatments, temporal scale can play an important role in determining the extent of treatment effects on N dynamics, and it is unclear to what extent the results of short-term studies can be extrapolated to responses over longer time scales. I compared the short-term versus long-term effects of N addition and warming on net N mineralization, N leaching, and N retention in a grass-dominated old field. …


Spatial And Temporal Variation Of Nutrients In The Great Lakes-St. Lawrence Basin: Implications For Primary Production In Stream Ecosystems, Nolan Pearce Aug 2020

Spatial And Temporal Variation Of Nutrients In The Great Lakes-St. Lawrence Basin: Implications For Primary Production In Stream Ecosystems, Nolan Pearce

Electronic Thesis and Dissertation Repository

Growing human populations and associated land use activities has increased the amount of nutrients delivered to surface waters. Eutrophication from the over-enrichment of nitrogen and phosphorus has degraded ecosystem conditions in streams, lakes, and coastal areas worldwide. Thus, the management of anthropogenic nutrient loading is a global concern. This thesis employed a combination of field and experimental research to provide watershed managers with information on the spatial and temporal patterns in stream nutrient enrichment, and the associated ecological effects of anthropogenic nutrient loading in the Great Lakes-St. Lawrence basin. Four studies were completed to address this research goal. First, I …


The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev Sep 2019

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and using …


First Major Appearance Of Brachiopod-Dominated Benthic Shelly Communities In The Reef Ecosystem During The Early Silurian, Cale A.C. Gushulak Aug 2016

First Major Appearance Of Brachiopod-Dominated Benthic Shelly Communities In The Reef Ecosystem During The Early Silurian, Cale A.C. Gushulak

Electronic Thesis and Dissertation Repository

The early Silurian reefs of the Attawapiskat Formation in the Hudson Bay Basin preserved the oldest record of major invasion of the coral-stromatoporoid skeletal reefs by brachiopods and other marine shelly benthos, providing an excellent opportunity for studying the early evolution, functional morphology, and community organization of the rich and diverse reef-dwelling brachiopods. Biometric and multivariate analysis demonstrate that the reef-dwelling Pentameroides septentrionalis evolved from the level-bottom-dwelling Pentameroides subrectus to develop a larger and more globular shell. The reef-dwelling brachiopods in the paleoequatorial Hudson Bay Basin were more diverse than contemporaneous higher latitude reef-dwelling brachiopod faunas, with ten distinct …


Exploration Of Spatial And Temporal Changes In Trophic Status Of Lakes In The Northern Temporal Forest Biome Using Remote Sensing, Aleksey Paltsev Apr 2015

Exploration Of Spatial And Temporal Changes In Trophic Status Of Lakes In The Northern Temporal Forest Biome Using Remote Sensing, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a critical need for detailed surveys of lakes covering large spatial (>100 km2) and temporal scales (decades) to determine if there is an increase in the magnitude and frequency of phytoplankton blooms. Remote sensing was used to: (1) develop a regression model that relates chlorophyll a (chl-a) as a proxy of lake phytoplankton biomass to Landsat TM and ETM+ optical reflectance (r2=0.85, p