Cryosphere and Carbon Cycle

Earth Systems Science Quiz 4

sea ice

ice that is floating on the ocean and is identified by age/thickness. In the Northern Hemisphere, its maximum extent is in March and its minimum extent is in September. The opposite is true of the Southern Hemisphere.

seasonal sea ice

also known as first-year ice, sea ice that forms each winter and is 0-1 years old

multi-year sea ice

confined to the poles, sea ice that persists/grows each year and is 1-5 years old

iceberg

once-glacial (ergo land-based) ice that broke off into the ocean

anomaly

the deviation of a variable from a long-term (typically 30 year) baseline or average

glacier

a mass of snow/ice on land that flows under its own weight and is confined by topography (often a valley)

ice sheet

a mass of snow/ice on land that flows under its own weight and is not confined by topography

accumulation zone

the area on a glacier or ice sheet where mass gain outweighs mass loss

ablation zone

the area on a glacier or ice sheet where mass is lost more than it is replaced

permafrost

ground that is at or below 0^oC for two or more years. It exists around the poles as well as the Himalayan mountain range

active layer

the layer of soil above permafrost that seasonally freezes and thaws (in response to air temperature flux)

expansion

the active layer’s depth increasing in response to a warming climate

seasonal snow

snow that falls but does not persist throughout the year. In the Northern Hemisphere, it reaches its maximum extent in January

shorefast ice

sea ice connected to land, stabilizing erosion and increasing transportation

organic carbon

carbon in C-C or C-H (ie. chemically reduced) bonds, often associated with living organisms. Examples include sugars, fats, carbohydrates, coal, methane (CH₄), and C in permafrost

chemically reduced bonds

weak, unstable, and electron-rich bonds that release energy when broken

inorganic carbon

the energetically favored carbon not contained in C-C or C-H (ie. chemically reduced) bonds. Examples CO₂ and CaCO₃

oxidized bonds

stable bonds that require energy to break

respiration (R)

CH₂O + O₂ → (metabolic energy) → CO₂ + H₂O

photosynthesis

CO₂ + H₂O → (sunlight) → CH₂O + O₂

keeling curve

the long-term record of mean monthly CO₂ (ppm) at Mauna Loa Observatory. CO₂’s annual cycle is dominated by boreal forests in the Northern Hemisphere, so it peaks in early spring and troughs in the fall.

net primary productivity (NPP)

the rate of accumulation of organic carbon in plants, as balanced by respiration and decomposition

net ecosystem production (NEP)

NPP - R, where a positive value is a carbon sink and a negative value is a carbon source

coal

organic carbon formed and compressed n a terrestrial/swampy environment where photosynthesis outpaces decomposition

oil/gas

organic carbon formed and compressed in a marine environment where photosynthesis outpaces decomposition

residence time

the average amount of time that a molecule stays in a given stock/reservoir (given that the stock is in a steady state): magnitude of stock / (inflow OR outflow)

air-sea exchange

a physical process of CO₂ diffusing/dissolving into the ocean and releasing into the atmosphere: CO₂ + H₂O <→ H₂CO₃ (carbonic acid) <→ H⁺ + HCO₃^- (bicarbonate ion) <→ H⁺ + HCO₃^2- (carbonate ion)

biological carbon pump

the movement/transfer/storage of organic carbon from the surface of the ocean to the deep ocean/ocean sediments

diatoms

photosynthetic, single-celled algae with silica cell walls currently responsible for 40-50% of all marine primary productivity

foraminifera

calcifying, heterotrophic marine organisms that eat diatoms

calcification

the ability of organisms to grow calcium carbonate shells