California Current &Barnacle larvae transport

Mikaela ProvostPhysical Oceanography 12/2/2010

California Current

-Eastern edge of the North Pacific Gyre.

-Moves south along the western coast of North America bringing cool water from Alaska to Baja California.

What sustains the CA current?

- Westerlie winds drive the California current

Upwelling is characteristic

pfeg.noaa.gov

- Ekman transport offshore yields strong upwelling along the CA coast, supporting a high level of marine biodiversity

Sea Surface Temperature

- Cool water, an indicator of upwelling.

- Transport can be as much as 300 m3/sec

- Strongest upwelling in summer

Currents and barnacle recruitmentQuestion facing many marine ecologists:

Observe large fluctuations in the abundance of barnacle stock populations, and yet the environment seems to be highly productive.

Each data point represents a total of 7 days of settlement of acorn barnacles on six 10 cm x 10 cm plates.

Upwelling Intensity & Population Variability

- Higher recruitment associated with weaker cases of upwelling.

- Intertidal barnacle larvae carried offshore with strong upwelling, lower probability of encountering adult habitat for settlement.

Reasons for variation in barnacle populations:

ReferencesAlexander and Roughgarden. 1996. Larval Transport and Population Dynamics of Intertidal Barnacles: A Coupled Benthic/Oceanic Model. Ecological Monographs 66: 259-275

Farrell etal. 1991. Cross-shelf transport causes recruitment to intertidal populations in central California. Limnological Oceanography 36: 279-288.

Shkedy and Roughgarden. 1997. Barnacle recruitment and population dynamics predicted from coastal upwelling. Oikos 80: 487-498.

http://mlo.stanford.edu/barnacles.htm