EARTH 222 Final: ocean final exam study guide
Premium

11 Pages
66 Views
Unlock Document

Department
Earth and Environmental Sciences
Course
EARTH 222
Professor
Brian Arbic
Semester
Winter

Description
LIGHT, NUTRIENTS, PHOTOSYNTHESIS, PRIMARY PRODUCTION (Lectures 20-22) ● 4 ingredients for photosynthesis ○ Water, CO2, nutrients, energy ● 2 ingredients for photosynthesis that are typically limiting ○ Nutrient availability ○ 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 ■ Upward scattering is termed backscattering ■ 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 ● why is the ocean blue and the Huron River brown? ○ 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 ○ Aphotic Zone: Portion of a lake or ocean where there is little or no sunlight ■ Depths beyond which less than 1% of sunlight penetrates ● basic chemical equations describing photosynthesis and respiration ○ Photosynthesis: 6CO2+6H2O→ C6H12O6+6O2 ○ Respiration: C6H12O6+6O2→ 6CO2+6H2O ● difference between autotrophs and heterotrophs ○ Autotrophs: Create their own food using external energy source through primary production ■ Plants, algae, some bacteria ○ Heterotrophs: Unable to make organic compounds from inorganic compounds, must eat autotrophs or other heterotrophs ■ All animals, most bacteria and fungi ■ Heterotrophs live only where autotrophs provide food source ● key limiting nutrient in the ocean and why it is required for photosynthesis ○ Iron ■ There are other things going on that require iron ● in the water column, where does primary production typically exceed respiration? where does the reverse occur? how does this affect the nutrient concentrations in these two zones? ○ Rate of primary production falls off rapidly with water depth, but respiration remains constant ○ Where P>R, autotrophs can grow and reproduce, producing more organic matter than they consume, creating food supply for heterotrophs ○ Where P=R, primary production and respiration are comparable. Typically at ~1% light intensity ○ Where P
More Less

Related notes for EARTH 222

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit