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Current Research:
For my master's work at Oregon
State University I am examining nutrient flux in watersheds at small and
large scales. Specifically, I am interested in hydrologic processes that control
nutrient export.
It is
understood that most of the organic matter in the streams comes from
terrestrial sources, how these organic constituents reach the stream channel
and what controls are exerted over these processes is not clearly understood.
I plan to characterize dissolved organic matter (DOM) to clarify sources of
organic matter to streams at my research site in the HJ Andrews Experimental Forest (HJA).
DOM in streams plays a strong
role in controlling stream chemistry and nutrient supply - critical for the
floral and faunal inhabitants of the stream. DOM also influences the
transport of heavy metals (i.e. Mercury). DOM is not a homogenous entity and
the variable quality and quantity of DOM has wide-reaching impacts. For
instance, high organic matter concentrations in drinking water facilities can
contribute to the creation of secondary chemicals as a part of the
chlorination process.
In the temperate rainforests
of the Pacific Northwest, where my research site is located, rain dominates
the calendar from October through May. During the summer months, little
precipitation falls and moisture becomes depleted from the soil profile.
Organic matter, which is produced and decomposed during the highly productive
summer months, is largely restricted to the soil profile and remains upslope
from the stream channel. The onset of the rainy season in the fall produces a
strong flushing effect, wherein the stored organic matter is quickly released
to the streams.
Hydrologic studies in the
watersheds of the HJA indicate that a significant portion of the stream water
during the winter come from groundwater sources. If groundwater dominates the
winter hydrograph, why is there such a strong flushing effect? During the
winter hydrograph, the proportion of water in the stream from groundwater
fluctuates, with multiple flow processes contributing to the stream. How do
the changing flowpaths affect the quantity and quality of DOM exported to the
stream? My work will address these questions.
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