announcements in class 2/5/07 movie wed. don’t miss it! material will be on the exam. only one...
TRANSCRIPT
Announcements in class 2/5/07
• Movie Wed. Don’t miss it! Material will be on the exam. Only one showing.
• Problem Set 4 is posted online. Print it out yourself. PS 4 is due in class Monday, 2/12/07
• PS 5 will be posted Mon. 2/12 and due Wed. 2/21
Outline
• f-ratio
• Phosphorous Cycling
• Carbon Cycling
NitratePhytoplankton
Up
wel
lin
gM
ixin
g
Vertical
Flux
N2 FixationRiversDeposition
PONDIN
Euphotic Zone
f-ratio
Upwelling Zone 0.8Gyre 0.1Global Average < 0.5
New Production
New + Regenerated Production
Sediment traps
to catch
sinking particles
Sustainable yields
NitratePhytoplankton
Up
wel
lin
gM
ixin
g
Ver
tica
lF
lux
N2 FixationRiversDeposition
PONDIN
Euphotic Zone
Fishing
New Production
Oligotrophic gyres
Upwelling regions
↑Annual ↓Perennialr-selected K-selected
Chemical Forms – P
• PO43- (Phosphate)
• Organic
The cycling of Phosphorus
Dissolved Inorganic Particulate Organic
uptake
excretion
Runoff
upwelling sinkingdecomposition
Balance maintained via weathering of rock
Chemical Transformations – P
• AssimilationPO4
3- → OrganicPhytoplankton or other autotrophs
• RemineralizationOrganic → PO4
3-
Heterotrophs
• ExcretionOrganic → DissolvedHeterotrophs and Autotrophs
Experimental Lakes Area
Lake 227
Lake 226C, N, PEutrophic algal blooms
C, N
Lake 227
Oligotrophic Lake Eutrophic Lake
25 - 100 micrograms/liter phosphorus > 15 micrograms/liter phosphorus
Chemical forms of Carbon• Inorganic
– CO2
– bicarbonate ion HCO3-
– carbonate ion CO32-
• Organic (fixed …)
• Dissolved (DIC and DOC)
• Particulate (biomass and detritus)
Carbonate Equilibrium
• CO2 «» HCO3- «» CO3
2-
dissolved bicarbonate carbonate
CO2 ↑ HCO3- ↑ CO3
2- ↑ pH ↓
Ocean pH 8.2
Source R. Rohde
C Cycle “Food Web” Diagram
P
Z
BDissolvedInorganicCarbon
DissolvedOrganicCarbon
Main Thermocline
CO2
DissolvedInorganicCarbon
DissolvedOrganicCarbonDeep Remineralization
Sinking Particles
PteropodForaminiferaCoccolithophore
Carbon
• Solubility Pump– Solubility of CO2 is greater in cooler water
– Deep water formation ↑DIC– C pumped from atmosphere to ocean
• Biological Pump– POC and PIC sinking, DOC downwelling– C pumped from surface ocean to depth
Deep Water Formation
Source: USC
Thermohaline circulation
Saharan Dust Storm Over the Atlantic
The Cycling of Silicon
Dissolved Inorganic Particulate Organic
uptake
Runoff
upwelling sinkingdissolution
Balance maintained via weathering of rock