1. Nutrients & Tracers Nutrients & Tracers http://oceancolor.gsfc.nasa.gov/cgi/image_archive.cg?http://oceancolor.gsfc.nasa.gov/cgi/image_archive.cg?c=CHLOR OPHYLL

2. The food chain is not a nice thing: Big animals eat little animals Little animals eat plants What do plants eat?

3. Plants combine CO 2 and a variety of other nutrients (their food) with energy from light to make organic modules (our food). CO 2 + H 2 O CH 2 O + O 2 (Biomass, carbohydrates, etc)

4. Which is not a major ion? A) Sodium (Na + ) B) Potassium (K + ) C) Chloride (Cl - ) D) Silicon (Si) E) Sulfate (SO 4 2- ) Question

5. Which is not a major ion? A) Sodium (Na + ) B) Potassium (K + ) C) Chloride (Cl - ) D) Silicon (Si) E) Sulfate (SO 4 2- ) Major ions are Cl -, Na +, SO 4 2-, Mg 2+, Ca 2+, K + Question

6. Non-conservative element: ✤ short residence time ✤ removed efficiently by biological or chemical processes Nutrients: ✤ used by living organisms ✤ Carbon, Nitrogen, Phosphorous, Iron, silicate, and others

7. Phytoplankton are microscopic plants are the basis of the marine food web they photosynthesize Phyto = plant, plankton = wandering (Greek)

8. Phytoplankton grow by ‘eating’ dissolved chemicals Essential nutrients: for soft tissue Carbonas Bicarbonate ionHCO 3 - Nitrogen as Nitrate as Ammonium NO 3 - NH 4 + Phosphorou s as PhosphatePO 4 3-

9. Phytoplankton grow by ‘eating’ dissolved chemicals Micronutrients: used in very small amounts Magnesiumused in chlorophyll Ironused in photosynthesis Seleniumused in enzymes etc Mistaken identity? Cadmiummistaken for PO 4 3- Bariummistaken for Si

10. Skeleton building chemicals Phytoplankton grow by ‘eating’ dissolved chemicals Calcium (Ca 2+ ) Silica (SiO 2 )

11. Nutrient sources CarbonCO 2 in atmosphere Nitrogen Atmospheric N 2 can not be used Needs to be “fixed” into NO 3 - or NH 4 + Most fixed in-situ Some from rain and rivers PhosphorousRain and rivers Iron Dust from the continents carried by wind

12. Photic zone Energy from light gets stored in organic (carbon containing) compounds

13. Some nutrients (like PO 4 3- and SiO 2 ) have long residence time, but are biologically active. Photosynthesis can only occur near the surface, where there is light. Therefore, nutrients will be: A) Depleted with depth B) Depleted at the surface C) Unchanged with depth Question

14. Some nutrients (like PO 4 3- and SiO 2 ) have long residence time, but are biologically active. Photosynthesis can only occur near the surface, where there is light. Therefore, nutrients will be: A) Depleted with depth B) Depleted at the surface C) Unchanged with depth Question

15. Station ALOHA Hawaii Ocean Time- series

16. Vertical distribution of major ions

18. HOT profiles 0 1000 2000 3000 4000 5000 Depth [m] 02040 NO 3 [  M/kg] 0123 PO 4 [  M/kg]

19. Sections Pacific (P16) Atlantic (A16)

20. Pacific Ocean http://www-pord.ucsd.edu/whp_atlas/pacific/p16/sections Eq60 o S55 o N 0 0 6.5km Nitrate Phosphate

21. Atlantic Ocean Eq50 o S60 o N 0 0 6km Nitrate Phosphate http://www-pord.ucsd.edu/whp_atlas/atlantic/a16/sections

22. Limiting nutrient Nitrate and phosphorous low in upper ~140 m 0 100 200 300 400 500 Depth [m] 0 NO 3 [  M/kg] 1020300 PO 4 [  M/kg] 12 At HOT Nitrate goes to zero - Limiting nutrient

23. Why 140m? (Varies from place to place) 0 50 100 150 Depth [m] 0100200 Photosynthetically available radiation (PAR) Below about 100 m, there is no light left in the ocean. The deeper ocean is totally black.

24. Why 140m? (Varies from place to place) Photosynthes is only possible to ~ 1% light level 0 50 100 150 Depth [m] 0100200 80 100 120 140 48 Photosynthetically available radiation (PAR) Below about 100 m, there is no light left in the ocean. The deeper ocean is totally black.

25. Likely iron (Fe) limitation In some places neither NO 3 - nor PO 4 3- go to zero Annual mean surface Nitrate

26. Dust carries iron Husar et al., 1997 SeaWiFS

27. Iron fertilization These patches of chlorophyll were created by adding iron to the Southern Ocean Iron was the limiting nutrient in this case Irod et al., 2005

28. How much dust do you think is deposited on the surface of the ocean each year? A) 10 tons B) 300 tons C) 5,000 tons D) 10 million tons E) more Question

29. How much dust do you think is deposited on the surface of the ocean each year? A) 10 tons B) 300 tons C) 5,000 tons D) 10 million tons E) more 358 million tons Question

30. Recycling soft tissue Organisms can almost completely remove NO 3 - and PO 4 3- from the surface ocean How are nutrients restored so life can continue?

31. Recycling soft tissue Organisms can almost completely remove NO 3 - and PO 4 3- from the surface ocean

32. How much biological material (organic C) do you think is produced in the surface ocean each year? A) 1 thousand tons B) 50 thousand tons C) 1 million tons D) 1 billion tons E) 50 billion tons Question

33. How much biological material (organic C) do you think is produced in the surface ocean each year? A) 1 thousand tons B) 50 thousand tons C) 1 million tons D) 1 billion tons E) 50 billion tons 50 billion tons = 50x10 12 kg Question

34. Not eaten - not an energy source Slowly dissolve (mainly at seabed) Some buried in sediments Paleo-recorders of ocean chemistry Recycling skeletons 0 1000 2000 3000 4000 5000 Depth [m] 0 SiO 2 [  M/kg] 100200

35. Silicate @ HOT 0 1000 2000 3000 4000 5000 Depth [m] 02040 NO 3 [  M/kg] 00123 PO 4 [  M/kg]SiO 2 [  M/kg] 4080120

36. Silicate sections Pacific Atlantic http://www-pord.ucsd.edu/whp_atlas/atlantic/a16/sections http://www-pord.ucsd.edu/whp_atlas/pacific/p16/sections Color scales are not the same

37. Chemicals as tracers Tritium ( 3 H) from H-bomb tests

38. 3 H in North Atlantic 19721981 1 and 2 TU contours plotted Input of Tritium into ocean peaked in 1963-64

39. 3 H in Indian Ocean Eq 60 o S http://www- pord.ucsd.edu/whp_atlas/indian/i08i09/sections/ 0 6.5km

40. Non-conservative elements have short residence times compared to the ocean stirring time. Many are used in biological processes. Nutrients are used by living organisms. Silicon or calcium used for shells. Photosynthesis can only occur where there is light. Most of the ocean is dark. Around Hawaii the ‘Photic zone’ is about 140m deep. Limiting nutrient is an essential nutrient, that if missing, prevents growth. Non-conservative elements make good tracers of ocean currents. Some key ideas