GEOSC 040 Lecture Notes - Lecture 5: Halocline, Pycnocline, Thermocline
Document Summary
Chemistry of sea water- dissolved gas and density. There is a systematic pattern of currents in the ocean. The buoyant layers are on top because it"s the least dense. Freshwater- there is a maximum in density where the water doesn"t freeze. When you add salt to water, it depresses the freezing point. Makes water the stable phase instead of ice. Density of seawater increases as temperature drops and salinity increases. Pyncoline is the zone of rapid density change with depth. Because water has a low viscocity and can flow, denser water masses sink while less dense water rise. Residence time of deep water in the large ocean basins- between 500-2000 years depending on basin. T=volume/influx: phosphate is used rapidly in the ocean, the reason cl residence time is longer is because it isn"t used as much. Gases are soluble in seawater in proportion to their atmospheric concentration gas exchange: gas exchange is enhanced by mixing and biologic processes.
