Big Ideas

The California Current Ecosystem LTER takes an interdisciplinary approach to studying the marine ecosystem. This involves a multi-level investigation of how physical, chemical and biological coupling works in order to better understand how the whole system responds to long-term climate variability.  Take a moment and explore some of the ‘Big Ideas’ that we’ve highlighted. Read about how they relate to each other and the importance of studying them as they pertain to the research of the California Current Ecosystem.

What is the California Current?

Water in motion is called a current. The California Current (CC) extending from British Columbia south to Baja California, is part of a larger North Pacific gyre – a large, clockwise moving current along the west coast of North America.

The California Current, like many other currents, is affected by a combination of global wind patterns around the Earth, unequal solar radiation distributed between northern and southern hemispheres, the Earth’s rotation and the Coriolis effect.

The water moves south, bringing with it the cooler waters from the Alaskan Current. The CC is particularly influenced by prevailing northwesterly winds. These winds cause surface waters to be pushed offshore allowing colder subsurface water to be drawn up. This is called upwelling. These upwellings create a nutrient-rich environment and support a diverse and complex ecosystem by recycling nutrients, and increasing the biomass of the food web.

Scientists study the California Current as it is a sustainable environment for a variety of finfish, and marine invertebrates but also because of its influence on weather patterns and the water cycle along the western United States. It plays such a vital role in the economy of a myriad of coastal communities. Investigating what mechanisms lead to changes in this California Current Ecosystem, its role in ocean climate change and ecosystem dynamics is what researchers continue to study. Go to http://cce.lternet.edu/ to learn more about the research.

How does Upwelling Affect Ecosystem Dynamics in the CCE?
 

California’s near shore waters are a rich and varied environment supporting an array of marine life. Its topography is characterized by a narrow continental shelf that slopes away from the coast descending to deep submarine canyons. This shelf meets the sea floor and becomes the open ocean.

Seasonal cycles and favorable wind conditions often influence these near shore waters comprising the California Current. The result? The winds drive surface waters offshore and get replaced with deep, cold nutrient-rich water full of dissolved organics. This process is called upwelling. It brings a cocktail of nitrogen, phosphorus and silicates recycled from life at the surface (Wong, 2006). There are typically strong seasonal cycles associated with upwelling, beginning in March and continuing through until September. Fluctuations in upwelling are known to have considerable impact on the coastal ecosystem and its response.

Firstly, upwelling stimulates and supports the foundation of the food web – affecting the production of single-celled plants called phytoplankton. Bathing in these nutrient waters allows phytoplankton to grow lavishly. This creates increased nutrient stratification in the water resulting in the arrival of grazers – krill, copepods and larval fish (or zooplankton) – who come to these areas to greedily feed on the phytoplankton. Larger predators, like seabirds, sea lions, whales, and even great white sharks circle these areas to claim their share.

The timing, strength, and extent of the seasonal cycles of upwelling, coupled with cyclical wind patterns, often changes phytoplankton production. So, when nutrient supplies are reduced, and upwelling decreases it limits the growth rates, sizes and survival of many larvae depending on phytoplankton concentrations. Consequently, this suppress reproductive output for many species and diminish food supply for predators. These implications radiate throughout the food web (Barth, 2007). The entire California Current Ecosystem responds.

Resources:

  1. Wong, K (2006) A Moveable Feast: The Ups and Downs of Coastal Upwelling. http://baynature.org/articles/jul-sep-2006/a-moveable-feast/?searchterm=the%20ups%20and%20downs%20of%20upwelling
  2. Barth et. al. (2007) Delayed Upwelling alters near shore coastal ocean ecosystem in the northern California Current, Proceedings of the National Academey of Sciences (PNAS) March 6:104 (10) pages 3719-3724. Online: http://www.icess.ucsb.edu/~washburn/pubs/barth_et_al_pnas_2007.pdf
  3. Ginsberg J. (1987) California Coastal Resource Guide, California Coastal Commission, California Coastal Commission, Madge Caughman, Published by University of California Press, ISBN 0520061861, 9780520061866 / 384 pages.

Who are the players in the California Food Web? 

 

 

Is there Evidence of Climate Change in the CCE?