ZOL 355 Lecture 13 Outline of Current Lecture II Carbon Cycle III Temperature increase IV Primary Production of oceans V Oceans as a sink Current Lecture I II III IV Importance of the carbon cycle a temporal variation in atmospheric CO2 always been fluctuation b anomaly commuted relative to average of period Temperature increase is less than expected given cumulative CO2 production a the earth should be warmer that it is when looking at CO2 levels b some CO2 is missing Ocean primary production a Photosynthesis productivity occurs in the photic zone b light attenuates with depth Oceans as a sink for CO2 a for a reservoir to be a sink it must be able to retain a large amount of CO 2 for a long period of time b CO2 can be stored in different forms organic vs inorganic carbon c Organic carbon component that belongs to something that was or is alive d inorganic carbon solid shell of a clam CaCO3 tests phytoplankton shells protection i gas CO2 HCO3 CH4 ii minerals not tissues e organic matter must be produced and buried f inorganic matter must be produced and remain in tact cant dissolve g organic can be produced in high abundance by phytoplankton blooms then reach sediments and be preserved h Biological pumpi biologically mediated production delivery and preservation of carbon from the surface of the oceans to the sediments ii in the role of oceans as a sink for CO2 this carbon cannot be changed back and consumed respired iii we will consider organic and inorganic components of the BP separately iv Organic component begins in the photic zone with primary production v PP predominate over R in the photic zone i j vi aphotic not sufficient light for photosynthesis mno live phytoplankton POM is degraded particulate organic matter POM vii throughout water column POM is consumed by herbivores and remineralzied to CO2 viii Photic zone PP dominates over R P R 1 net autotrophy ix aphotic zone R dominates over PP P R 1 net heterotrophy x CO2 stays in lower ocean good influences of biological pump on water column gases articles and chlorophyll concentration i lots of chlorophyll in upper decline in the lower because they are being consumed by heterotrophs ii CO2 low in upper increases with depth R is occurring iii O2 high in upper decreases with depth because R is occurring Inorganic Carbon i primarily from phytoplankton test that are made of CaCO3 ii accumulate and create very large deposits White Cliffs of Dover iii CaCO3 formation Ca CO32 iv CaCo3 dissolution CaCo3 H Ca HCO31 due to decrease in Ph increase in Co2 more H decrease in pH dissolution CO2 increases pH decreases as the shells fall lots of CO2 pH declines they start to degrade v declining pH on carbon sink dissolution of CaCO3 tests reduced potential of oceans to act as a CO2 sink if CO2 emerges from ocean