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Lecture 7
Light Reactions and Primary Productivity
Question | Answer |
---|---|
light independent reactions of photosynthesis occur as a cyclic pathway called the... | Calvin-Benson Cycle |
Light Independent Reactions are driven by energy from... | ATP |
What delivers hydrogen and electrons to build sugars? | NADPH |
What provides the carbon and oxygen? | Carbon Dioxide |
The enzyme that catalyzes the Calvin-Benson cycle: | Rubisco |
how much of primary productivity are phytoplankton responsible for? | 90-96% |
the reaction in which sugars produced by photosynthesis are broken down by phytoplankton using oxygen | respiration |
the yields of respiration are... | carbon dioxide, water, and energy |
three main methods of measuring primary productivity: | 1. measure the evolution of oxygen in bottle over time 2. measure the rate of fixation of radioactive Co_2 into particulate matter 3. use a satellite |
most often used method to measure primary productivity: | based on the uptake rate of radioisotope in the form of 14CO_2 |
what is incorporated into glucose produced during photosynthesis, glucose is used to make other phytoplankton parts | 14C |
the amount of 14C in the phyoplankton, measured with a scintillation counter, taken up per unit times is used to measure of what? | NPP |
what 4 things are the main determinants of production patterns in the ocean? | light, nutrients, temperature, and grazing |
light, nutrients, and temperature vary with | latitude |
where is production is often limited by light | in polar regions |
when is primary production maximum? | spring or early summer |
where does very little vertical mixing, low nutrient concentrations in the photic zone, consistently low primary production by phytoplankton (no blooms)? | in tropical regions |
where do two blooms occur during the spring and (smaller) in the fall? | in temperate regions |