Biological Pump and Geochemical Cycles Flashcards
What is the biological pump?
The ocean’s biologically driven sequestration of carbon from the atmosphere to deep sea water and sediment
What are the three phases?
Fixation: production of fixed carbon by planktonic phototrophs in the euphotic (sunlit) surface region of the ocean
Carbon particle settling/sinking as marine snow, is often recycled on the way down
Carbon particle recycling
What is the Redfield ratio?
The ratio of carbon to nitrogen and phosphorus, which varies little and has an average ratio of 106C:16N:1P
What is the biological part of the carbon cycle?
Carbon dioxide from the atmosphere is taken up by photosynthetic organisms and used to make organic molecules, which travel through food chains. In the end, the carbon atoms are released as CO2 in respiration.
Why are polar ice caps melting a positive feedback?
A common example of positive feedback loop is related to the factors you mentioned plus snow. One of global warming’s effects we frequently hear about is the melting of the ice caps. As carbon dioxide levels rise, the temperature increases causing more snow to melt. Well, snow is great at reflecting light, due to being white, which keeps surface temperatures cool. When snow melts, the ground exposed is darker and absorbs more light causing surface temperatures to rise. Higher surface temperature means more snow melting. So you begin to see a loop. To put it succinctly, global warming leads to warmer surface temps. which leads to more snow melting, which leads to warmer surface temps, which leads to more snow melting.
This is called the ice-albedo feedback effect.
What is the geologic pathway of the carbon cycle?
The geological pathway of the carbon cycle takes much longer than the biological pathway described above. In fact, it usually takes millions of years for carbon to cycle through the geological pathway. Carbon may be stored for long periods of time in the atmosphere, bodies of liquid water—mostly oceans— ocean sediment, soil, rocks, fossil fuels, and Earth’s interior.
What is the mechanism for carbon moving geologically?
The carbonate C032-combines with Ca2+ ions to make calcium carbonate - a key component of the shells of marine organisms. When the organisms die, their remains may sink and eventually become part of the sediment on the ocean floor. Over geologic time, the sediment turns into limestone, which is the largest carbon reservoir on Earth.
On land, carbon is stored in soil as organic carbon from the decomposition of living organisms or as inorganic carbon from weathering of terrestrial rock and minerals. Deeper under the ground are fossil fuels such as oil, coal, and natural gas, which are the remains of plants decomposed under anaerobic—oxygen-free—conditions. Fossil fuels take millions of years to form. When humans burn them, carbon is released into the atmosphere as carbon dioxide.
What is the nitrogen cycle?
The biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification
What is the water cycle?
The water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor.
The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate.
