marine iron cycle n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Marine iron cycle PowerPoint Presentation
Download Presentation
Marine iron cycle

Loading in 2 Seconds...

play fullscreen
1 / 18

Marine iron cycle - PowerPoint PPT Presentation


  • 264 Views
  • Uploaded on

Marine iron cycle. Nutrient dynamics in the deep blue sea – David M. Karl What controls dissolved iron concentrations in the world ocean? – Kenneth S. Johnson e.a. A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization – Philip W. Boyd e.a. Content.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Marine iron cycle' - delora


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
marine iron cycle

Marine iron cycle

Nutrient dynamics in the deep blue sea – David M. Karl

What controls dissolved iron concentrations in the world ocean? – Kenneth S. Johnson e.a.

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization – Philip W. Boyd e.a.

content
Content
  • History
  • Iron profiles
  • Iron spread in oceans
  • The role of iron in controlling oceanic productivity
  • Measurements
  • Conclusions
history
History
  • First measuring of iron in oceans
  • In 1988 Martin and Fitzwater first consider that iron is limited the primary production in HNLC-areas:
    • Sub artic Pacific ocean
    • Equatorial up welling zone of the Eastern Pacific Ocean
    • Ice-free Southern ocean
  • Afterwards many scientist focus their research on the iron-cycle
dissolved iron 1
Dissolved iron (1)
  • Iron profiles have uniform shape
  • Concentrations at surface <0.2 nmol kg-1
  • Average concentration:
    • At surface 0.07 nmol kg-1
    • Below 500 m. 0.76 nmol kg-1
  • Total average: 0,38 nmol kg-1
  • NO inter-ocean fractionation
why nutrient like profiles
Why nutrient like profiles?

Mechanisms to maintain constant iron concentrations in the deep-sea:

  • Binding by organic ligands
  • Equilibrium between dissolved and suspended particulate iron
particulate iron 1
Particulate iron (1)
  • Concentrations are <1 nmol kg-1
  • Concentrations increase with depth: in deep water concentrations between 0.2 and 0.8 nmol kg-1
offshore gradients 1
Offshore gradients (1)
  • Most of the supply in ocean derived from wet deposition of dust originating from continental sources
  • Aeolian supply:
    • Seasonally phased
    • Interannually variable
    • Climate sensitive
offshore gradients 2
Offshore gradients (2)
  • Horizontal variability:
    • high concentrations near shore
    • Low concentrations in the open ocean
correlation
Correlation

Correlation between integrated iron concentration and iron flux from the atmosphere

R2 = 0,34

primary production 1
Primary production (1)

Production of organic matter is sustained by a continuous supply of:

  • Usable energy
  • Life’s essential building blocks
  • Essential major elements: C, N and P
  • Essential minor elements: Fe and Zn
  • And for many marine organisms: essential trace organics such as B-complex vitamins
n 2 fixing
N2 fixing
  • Fe is extremely insoluble in oxygenated seawater, so the bio availability of Fe is controlled by presence of organic ligands that enhance Fe solubility
  • N2 fixing micro-organisms needs Fe for N2 reduction
  • N2 fixation continuous until, for example, Fe limits further growth
conclusions
Conclusions
  • Although Fe is a minor nutrient it is an important nutrient in the primary production process
  • Fe plays an important role by N2 fixing
  • There still a lot research to do