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
Pycnocline
gradient in density in relation to ocean depth. Lowest at surface, higher rate of increase in density at pycnocline, continues increasing with depth
Density
specific gravity of water. 1.00000 at 4 degrees celsius. Product of waters’ salinity and temperature
How do you identify different water masses
By their densities
AIW
Antarctic Intermediate Water, 33.8% salinity, temp 2.2 degrees celsius
ABW
Antarctic Bottom Water, 34.62% salinity, temp -1.9 degrees celsius
Sound propagation relationships
Velocity increases with increased temperature and increased pressure. Temperature effects dominate in shallow water, pressure effects dominate in deep water. Minimum velocity layer where it is too cold and there is not enough pressure.
SOFAR Zone
Sound fixing and ranging zone, where sound travels at a high speed at the bottom of the mixed layer, 80m, just above the pycnocline. Important for submarine communication. Shadow zone where very little sound energy penetrates, subs can use this to hide.
Hypoosmotic
Less salinity in their bodies than in external environment. Must drink weawater, secrete salt, excrete small amounts of concentrated urine
Optical properties
Incident light, reflection, attenuation, absorption and scattering
Incident light
Light at surface of sea, direct or diffuse
Reflection
Influenced by sea state, waves, foam patches, bubbles
Attenuation
Way the amount and spectral composition of light change with depth. Different colors attenuate at different rates, red light is defracted much more quickly.
Absorption and scattering
Reason light decreases exponentially with depth
