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Full-Text Articles in Life Sciences

Foliage Type Controls Mercury Input, Storage, And Release In The Boreal Forest, Madelaine J R Anderson Aug 2020

Foliage Type Controls Mercury Input, Storage, And Release In The Boreal Forest, Madelaine J R Anderson

Electronic Thesis and Dissertation Repository

Mercury (Hg) is a naturally occurring element with a complex biogeochemical cycle. Forests act as net sinks for both carbon (C) and Hg as foliage accumulates Hg with time. Litterfall represents a main input of C and Hg into forest soils. My aim was to investigate how foliage type (coniferous, deciduous) governs the input of Hg into forests with a field-based study that measured Hg accumulation over a growing season, and then investigate the storage and release of Hg from foliar tissues into soil with a laboratory-based incubation experiment. Results from the field-based study demonstrate deciduous leaves have more linear …


Elevated Temperature And Co2 Concentrations Affect Carbon Flux In Two Boreal Conifers, Sasha Madhavji Sep 2017

Elevated Temperature And Co2 Concentrations Affect Carbon Flux In Two Boreal Conifers, Sasha Madhavji

Electronic Thesis and Dissertation Repository

Elevated temperatures and CO2 will alter carbon flux in two dominant boreal tree species Picea mariana (black spruce) and Larix laricina (tamarack). Trees were grown in three temperature treatments (ambient, ambient +4 °C, and ambient +8 °C) at either 400 ppm or 750 ppm CO2, to simulate climate conditions between now and the year 2100. Spruce acclimated to increasing temperature detractively; warming scenarios reduced spruce net carbon gain. Tamarack maintained comparable levels of net photosynthesis (Anet) across warming treatments and both species acclimated respiration (Rdark) with increasing growth temperature. Elevated CO2-grown …


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


Multiple Approaches For Assessing Mangrove Biophysical And Biochemical Variables Using In Situ And Remote Sensing Techniques, Francisco Javier Flores De Santiago Jun 2013

Multiple Approaches For Assessing Mangrove Biophysical And Biochemical Variables Using In Situ And Remote Sensing Techniques, Francisco Javier Flores De Santiago

Electronic Thesis and Dissertation Repository

Mangrove forests are important ecosystems and play a key role in maintaining the equilibrium in coastal lagoons and estuaries. However, in recent years, there has been a considerable loss of mangrove extension due to anthropogenic activities. Recent studies suggest that multiple in situ and remote sensing approaches must be carried out to understand the dynamics in these complex ecosystems. Therefore, the objective for this PhD dissertation is to develop multiple techniques for monitoring the seasonal biophysical and biochemical conditions of the mangrove forests. Particular objectives will include: i. Test the feasibility of using a Chlorophyll Content Index from a …