Coastal Upwelling

1
Coastal Upwelling
2
What comes up

• Equatorward winds drive nearshore upwelling
• Reversals of these winds have important effects
  -gt downwelling
• Has implications for recruitment of near-shore
  fishes invertebrates

3
UPWELLING Cooling inshore Strong geostrophic
current DOWNWELLING Warming inshore
Weak (or reversed) current
4
Coastal Dynamics Experiment
5
(No Transcript)
6
(No Transcript)
7
Many Organisms Have an Obligate Larval Stage
8
A Typical Life Cycle

• Larvae are released to develop in plankton
• They disperse in the currents
• A select few settle on suitable habitat
• Even fewer recruit to adults
• The cycle repeats (if theyre lucky)
• KEY ELEMENT gt Larval Transport

9
Who are we talking about??

• Species with limited adult home ranges
• sessile adults
• Rockfish, kelp bass, urchin,
• Not tuna, sardine, whales, ...

10
Dispersal Scales for Marine Organisms
Kinlan Gaines 2003 Ecology
11
Dispersal Time in Plankton
Genetic Dispersal Scale (km)
The longer the development time, the further the
mean dispersal
Pelagic Larval Duration (days)
Siegel et al. 2003 Marine Ecology Progress
Series 260 83-96
12
Winds and Larval Transport
13
The Larval Pool Hypothesis
Well-Mixed Larval Pool
Cross-Shelf Transport
Settlement Sites
Distance -gt
14
Winds and Larval Transport
15
(No Transcript)
16
(No Transcript)
17
Winds and Larval Transport
18
Up/Downwelling Settlement
19
Coastal Downwelling

• Tightly linked to synoptic wind patterns
• Storm events driving day to week variability in
  thermocline depth
• Superimposed on seasonal pattern
• Which is superimposed on climate cycles

20
Coliform Bacteria Up/Downwelling
21
Coliform Bacteria Up/Downwelling
22
Coliform Bacteria Up/Downwelling
23
Coliform Bacteria Up/Downwelling
24
Downwelling in CA Current

• Downwelling brings surface water parcels to shore
  
• Important for recruitment of intertidal and
  subtidal organisms
• Also has role in pollutant dispersion