Seabirds, marine mammals, fish, and even tiny invertebrates can teach us about how climate change affects our oceans and the animals living in it.

Understanding how climate change affects the ocean ecosystem is no easy task.  The ocean is diverse and complex.  Birds, marine mammals, and their prey are affected by ocean conditions influenced by climate, such as upwelling, sea surface temperature and El Niño/La Niña events.

Below is a summary of how climate affects the predators and prey of the Marine Ecosystem.

Climate Impacts on Reproduction and Survival 

Seabirds and marine mammal reproduction and survival is affected by climate change through changes in timing of breeding, reproductive success, survival, and distribution/abundance.  Seabirds do best when their breeding is aligned with plenty of food in the ocean.  Good upwelling and low sea surface temperature are needed to have plenty of prey (krill and fish and squid) in the ocean.

• Studies off central California have shown that seabirds can sometimes modify their timing of breeding:
  Publications:  Abraham & Sydeman 2004, Roth et al. 2005, Wolf et al. 2008, Roth et al. in prep 
  
• When seabirds can’t modify their timing of breeding, they may not reproduce, may reproduce less, or have diminished nestling growth. 
  
• Cassin’s Auklet Nest Failure, 2005 and 2006: Failure to reproduce was documented at the Farallon National Wildlife Refuge in 2005 and 2006 for the entire colony of Cassin’s Auklets, a krill-eating seabird.  This was due to decreased krill abundance in the ocean causing late timing of nesting and reduced breeding success.  At the same time, Common Murres, which feed on fish, weren’t as profoundly affected. Publications: Jahncke et al. 2008

• Warm-water years (associated with reduced upwelling) generally result in reduced seabird productivity.
  
  This was shown in research conducted in the Gulf of the Farallones National Marine Sanctuary. Publications: Ainley et al. 1995, Abraham & Sydeman 2004, Jahncke et al. 2008, Roth et al. in prep 
  
• Larger oceanic processes such as the Pacific Decadal Oscillation (PDO) have been shown to influence seabird productivity. Our studies found that when the PDO was in a negative phase high breeding success occurred for murres on Southeast Farallon Island and low breeding success was seen during positive phases. Roth et al. in prep
  
• Nest Abandonment
  On the Farallon Islands, PRBO researchers observed unprecedented breeding failure of Cassin’s Auklets. In 2005 and 2006, changing climate patterns delayed spring  upwelling, which normally brings nutrients to the food web and supplies food (e.g. krill) to Cassin’s Auklets. Without the upwelling, the auklets didn’t have enough food to raise their young, and thus abandoned their nests.