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Lesson 4: The Biogeochemical Cycle Chemical Oceanography. Last class we learned about CO 2 in the oceans. What is the average pH in the ocean? How can increases in CO 2 affect: Ocean pH? Calcium carbonate? What substance do marine organisms use to make exoskeletons?.
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Lesson 4: The Biogeochemical Cycle Chemical Oceanography
Last class we learned about CO2 in the oceans • What is the average pH in the ocean? • How can increases in CO2 affect: • Ocean pH? • Calcium carbonate? • What substance do marine organisms use to make exoskeletons?
Today we will learn more about organic ocean chemistry • The biogeochemical cycle is the continuous flow of elements and compounds between organisms and the earth • The ocean plays a role in the biogeochemical cycle for elements including carbon and nitrogen • As part of the carbon cycle, carbon dissolves into the surface ocean from the atmosphere and is used for photosynthesis
The biogeochemical cycle Atmosphere The biogeochemical cycle involves the movement of elements and compounds among the land (lithosphere), organisms, air (atmosphere) and the oceans (hydrosphere). Human activities can affect these cycles Biosphere Hydrosphere Lithosphere
Elements Elements travel among air, land and sea through physical processes Elements Organisms use elements as nutrients and put nutrients back into the environment How do elements move through the biogeochemical cycle?
What elements are important to marine life? • Carbon (C) • Nitrogen (N) • Phosphorus (P) • Silicon (Si) • Iron (Fe) • Trace metals A trace element exists at LESS THAN 100ppm
Carbon cycling in the ocean: The “biological pump” • Today we will focus on carbon cycling. • We’ll examine the processes that transfer carbon from the ocean surface to the deep ocean and throughout the food chain.
Phytoplankton use CO2 for photosynthesis Some CO2 is given back off through respiration CO2 Carbon moves up the food chain as primary consumers like zooplankton eat phytoplankton CO2 Respiration Carbon moves further up to secondary and tertiary consumers Decomposition As phytoplankton die and decompose, carbon settles to the deep ocean
Student activity In today’s activity, we will read an example of modern scientists’ studies of biogeochemical cycles