lecture 2 cards Flashcards
Major ions in the ocean
Chloride, sulfate, bicarbonate, sodium, magnesium, calcium, potassium
Dipole
Opposite ends have opposte charges
H bonds
Bonds between hydrogen atoms on one molecule are strongly attracted to negative pole on another molecule without dissociating
Why are those particular ions in the water
Ions left behind after complex reactions occur in the water, like formation of organic matter, skeletons and sediments. Results of biological and geochemical processing.
Source of chloride in the ocean
Excess of volatile chloride from volcanic gasses, HCl
Processes that add ions to seawater
chemical weathering, cyclic salts
Processes that remove ions from seawater
Ion exchange, carbonate formation, reverse weathering, opal formation, sulfate reduction, evaporite formation
Chemical weathering
Action of water and carbon dioxide on rocks, producing calcium, bicarbonate and silicate ions. Silicate igneous rocks like granite and basalt and carbonate rocks are the most easily weathered
Cyclic salts
Ions like sodium and chloride that end up back in seawater due to the water cycle. These ions are in rainwater. Seawater is in steady state for chloride.
Ion exchange
charge balance, clay particles lose calcium ions for potassium ions in estuaries
Carbonate formation
Formation of CaCO3 from skeletons of organisms, making sediments
Reverse weathering
when ions in solution precipitate onto solid surfaces by adsorption
Carbonate compensation depth
point where the net change in weight of the spheres is zero. If the ocean bottom is above this CaCO3 sediments accumulate–little accumulation in pacific ocean
Opal formation
Skeletons from organisms like diatoms and radiolarians form silica oozes
Si
part of the long-term buffering system of the ocean
Sulfate reduction
Sulfides deposited as solids around hydrothermal vent systems due to bacteria, anaerobic
Evaporite formation
Different minerals precipitate out as seawater evaporates
Conservative
When ions have similar proportions in all the world’s oceans. Major ions.
Non-conservative
When organisms in the ocean determine the proportions in those waters. Minor and trace elements.
Alfred Redfield
Physiologist at Harvard/Woods Hole Oceanographic that made observations of nutrients in seawater, biochemical circulation
Biochemical circulation
Biologically active elements circulate in bodies of water very differently from general water circulation. Because processes of synthesis and regeneration can be separated in space–synthesis needs sunlight but regeneration can be at deeper depths
Redfield ratio
Average value for plankton of the three major structural elements. 106 C : 16 N : 1 P
Halocline
gradient in salinity in relation to ocean depth. Highest at surface because that’s where evaporation takes place. At Halocline sharply declines and then slowly increases again.
Thermocline
gradient in temperature in relation to ocean depth. Highest at surface, steeply declines at thermocline and then slowly continues decreasing with depth