trace elements dissolved in the oceans

Question 1

what are the major components in seawater?

Answer 1

• major ions = alkali earths and halides, bicarbonate and calcium

Question 2

minor constituents of seawater?

Answer 2

• Gases – N2, O2, CO2
• Nutrients – NO3-, PO42-, SiO2

Question 3

what is total dissolved load of elements entering ocean from rivers?

Answer 3

3.7 x10^15 g yr-1

Question 4

what is total particulate load entering ocean?

Answer 4

15.5 x 10^15 g yr-1

Question 5

elements entering oceans from the atmosphere?

Answer 5

• dry particles or wet deposition
• natural or anthropogenic
• may be particulate or dissolved form.
• inputs vary regionally

Question 6

what are hydrothermal fluxes to oceans

Answer 6

• scales of inputs not well known but for some may exceed riverine inputs
• some elements may precipitate very quickly on entering the seawater

Question 7

If we want to understand the dissolved minor or trace elements in the sea what do we need?

Answer 7

• name and nature of the chemical
• typical form in seawater
• conc.
• sources and behaviour
• distribution in oceans

Question 8

how will lithium and caesium behave?

Answer 8

• like NA+ - and other alkali metals
• little reactivity - conservative in seawater like sodium

Question 9

source of caesium?

Answer 9

• reprocessing of nuclear wastes
• may be used to track water

Question 10

are alkali earths transition elements?

Answer 10

yes

Question 11

what are examples of conservative elements?

Answer 11

• lithium
• molybdenum
• caesium
• tungsten

Question 12

what kind of elements are nutrients?

Answer 12

• iodine
• cadmium
• arsenic
• zinc

Question 13

characteristics of elements with nutrient like behaviour?

Answer 13

• low dissolved conc. at surface because of removal into biological systems
• higher dissolved conc. at depth where decomposition releases nutrients back into water