Hubbard Brook Flashcards
How can evapotranspiration be calculated from HB field data of forested watersheds?
P = S + ET
ET = P - S
where ET = evapotranspiration
P = precipitation (input)
S = streamflow (output)
What is considered nutrient input in a forested ecosystem like HB, according to Likens and Boorman?
precipitation (P) carrying chemicals
What is considered nutrient output in a forested ecosystem like HB, according to Likens and Boorman?
streamflow chemicals (S)
What is the mathematical relationship between precipitation and streamflow at HB?
P = ET + S
as P increases, S also increases (linear)
ET will not change over time because the buffer is maintained, the amount retained remains stable
What is the main source of silica at HB?
weathering of rocks
What is the fate of nitrate (NO3-) from precipitation during summer at HB?
Are nutrients lost evenly throughout the year in the streamflow at HB? explain
no
there’s a peak in the spring with the snowmelt (S > P) and a decline in the summer when there’s more water taken up by plants (S decreases)
What is the impact of clear cutting on mineral nitrogen?
huge loss of NO3- from leaching
How does Douglas-fir vary in nutrient budgets for Ca, Mg, K? explain
define mixotrophy
when organisms are both photosynthesizers and hetertrophs
Is mixotrophy important in Mirror Lake? where, why?
yes!! because they can photosynthesize and consume other organisms
common at surface in summer when lots of light
common throughout water column when less light
What kind(s) of cyanobacteria are found in Mirror Lake?
anabaena
chroococcus
merismopedia
Why are the cyanobacteria(s) found at Mirror Lake important?
because they are mixotrophs
Anabaena and Chroococcus can also fix N2
Who were the major authors from the HB models?
Likens and Bormann
What years did the HB study run?
1963-2013
What were the major papers published from the HB study?
Likens, G.E. (2013). Biogeochemistry of a Forested Ecosystem
Bormann, F.H., Likens, G.E. (1979). Pattern and process in a forested ecosystem
Likens, G.E. (1985). An ecosystem approach to aquatic ecology: Mirror Lake and its environment
What was the main lake involved in the HB model ecosystem study?
Mirror Lake
According to Likens and Bormann, what moves the inputs and outputs of ecosystems?
meteorlogic (atmospheric), geologic, and biologic drivers
in the conceptual model for HB, what are the inputs to an ecosystem?
meteorlogic (atmospheric) inputs
particulates in the air and gaseous particles
in the conceptual model for HB, what components are part of the intrasystem cycle of an ecosystem?
nutrients that have no prominent gaseous phase and cannot leave the boundaries of the ecosystem
organic compartment:
- living plant mass
- animal biomass (herbivore, carnivore, detritivore, omnivore)
- dead biomass (litter, dead animals)
available nutrients:
- on exchange sites
- in soil
primary and secondary minerals:
- mineral (rocks)
- precipitation
How are atmospheric inputs connected with the organic component of an ecosystem in the conceptual model?
atmospheric inputs are taken up by living organisms
and organisms release gases into the atmosphere
How are atmospheric inputs connected with the available nutrients of an ecosystem in the conceptual model?
atmospheric inputs are either wet or dry
wet: precipitation (snow, rain)
dry: ash, dust
are deposited onto plants or soil surfaces
organisms and soil release gases into the atmosphere
How are minerals connected with the available nutrients of an ecosystem in the conceptual model?
minerals can be released and become available through weathering of rocks
available nutrients can form secondary minerals and add to the mineral component
How are the organic components connected with the available nutrients of an ecosystem in the conceptual model?
living organisms can immobilize (uptake) forms of nutrients
living organisms can mineralize nutrients in the soil, leaching of nutrients, throughfall, streamflow, exudation of nutrients to enter soil