Composition of Seawater Marine Science Dissolved Materials Where

Composition of Seawater Marine Science

Dissolved Materials

Where do these salts come from? ● Rivers: - flow into the oceans, carrying minerals and salt from soil. ● Hydrothermal vents: -vents at the bottom of the ocean spew out minerals.

Residence Time: amount of time a particular ion stays in solution -minerals and salts cycle through the ocean ( every 8 -12 mil. yrs) -iron and sulfur form deposits -silicon and calcium incorporate into shells -some minerals lost at surface by wind Balance between incoming materials and outgoing materials

Salinity ● Amount of dissolved materials in seawater ~34. 7 ppt is average salinity ● Concentration of salinity varies around the globe -Evaporation and precipitation Increase salinity decrease salinity

Salinity Changes with depth. Gets lower with increasing depth. Halocline: water layer with large salinity changes. How does salinity affect marine organisms? -euryhaline: organisms that tolerate large salinity fluctuations (estuary) -stenohaline: organisms that cannot tolerate fluctuations (open ocean)

Dissolved Gasses

Dissolved Oxygen ● Gasses diffuse into the ocean from the atmosphere ● Photosynthetic organisms at surface make 50% of atmospheric oxygen ● Wind and waves increase oxygen diffusion into seawater -Rocky and sandy beaches have high amounts of D. O.

Dissolved CO 2 ● Stored in ocean as calcium and magnesium carbonates in animal shells and sediment. ● Fluctuates between 45 and 54 ml/L ● p. H stays between 7. 5 and 8. 4 ● Too much CO 2 increases acidity -Increasing acidity makes it harder for corals to build skeletons and for shellfish to build the shells they need for protection.

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