1. Carbon and Nitrogen Cycles in the Ocean MP 2.2

2. The Carbon Cycle All animals and most cells release CO 2. Plants use it to make food. CO 2 is highly soluble in seawater enters the ocean by dissolving at the surface as a dissolved gas.

3. Basic Equation: CO 2 + H 2 O  H 2 CO 3  H + + HCO 3-  2H + + CO 3- Carbon dioxide + water carbonic acidbicarbonate ionscarbonate ions When carbon dioxide dissolves it creates a weak acid, carbonic acid Carbonate and bicarbonate ions form from the carbonic acid and freely give up H+ ions. This helps to control the pH of seawater.

4. Animals like coral use carbonate to create their shells effecting the amount of CO 2 in the ocean. The total amount of CO 2 in seawater is 60X the amount in the atmosphere.

7. The Nitrogen Cycle

8. Oceanic Nitrogen Cycle Processes on – breaks stable nitrogen molecule Bacteria fixes atmospheric nitrogen and breaks down the products of excretion and decay. nitrogen is uptaken by phytoplankton causing them to grow rapidly Phytoplankton are then consumed by zooplankton and then they are consumed by fish and whales. Denitrification bacteria turn nitrates back into gas and released to atmosphere. – conversion of ammonia from waste and decomposition to nitrates that plants must consume to grow (like fertilizer). Nitrates are turned back into gas and released to atmosphere.