monitoring changes to the global water and carbon cycles

diurnal changes

significant changes can happen in 24hr periods
water:
- lower temps at night reduce evaporation and transpiration in water cycle, convectional rainfall a purely daytime phenomenon
carbon:
- during day CO2 flows from atomosphere to vegetation, opposite occurs at night

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seasons controlled by variations of solar radiation
evapotranspiration highest in summer, lowest in winter
river levels drop in hotter months due to this
in carbon cycle, NPP is highest in longer day lengths or photoperiods occuring in summer
when there is the most vegetation, carbon flows from atmosphere into biosphere, in winter when vegetation decomposes, the opposite occurs
in oceans phytoplankton are stimulated into photosynthetic activity by rising water temperatures, more intense sunlight and longer photoperiod

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earth's climate over the last million years has been massively unstable - ice age periods occur, lasting around 100,000 years each
world has also had much hotter periods too
both these occurences have implications on the water and carbon cycles

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glacial periods: water most commonly stored in ice sheets, glaciers and permafrost - cover a third of continetal land mass
global sea levels drop by 100-130 meters
biosphere shrinks
lowered rates of evapotranspiration - slows water cycle

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reduction of in CO2 in atmosphere during glacial periods - no clear explanations for why this occurs
vegetation reduced in colder climate, therefore as does the carbon stored
carbon stored in soils is trapped under the ice, meaning carbon exchanges between soil and atmosphere disappear
carbon mostly stored as permafrost
NPP falls, as do decomposition rates
carbon cycle overall slowed

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