EARTH 222 Final: ocean final exam study guide
17 Apr 2017
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Document Summary
2 ingredients for photosynthesis that are typically limiting. Energy- solar radiation is the primary energy source, light availability determines where and when photosynthesis occurs. Key factors that affect transmission of light through water (absorption and reflection) Absorption: water absorbs sunlight, very little penetrates to depths below ~100 m. Only short wavelength, high energy part of spectrum makes it to 10m and below (blue-green light) Reflection and scattering: light rays encounter rough, uneven surface and reflect in different directions. In clear water, scattering is limited and most red and yellow light absorbed, reflected light is blue-green. In turbid, ie high particle content water, most visible wavelengths are backscattered. Ocean has clear water- absorbs red and yellow light; reflects blue and green back. Difference between photic zone and aphotic zone. Photic zone: zone in the upper ocean where light is of sufficient intensity to support photosynthesis (~21% of the surface value) Most marine plants live in photic zone.
