A lot of people think that the ocean should have clear blue waters like the ones on tropical vacation photos. That’s not the case for California’s seabirds. They prefer the ocean to have a murkier green color as it signals a phytoplankton bloom that boosts the food web and provides more fish for them to eat.
From NOAA’s Green Seas Blue Seas website: “Through oceanographic surveys of the region’s chemical, physical and biological make up, scientists discovered a steady, long-lasting cycle of natural climate variability that alternates between warmer and cooler temperature regimes, often called the Pacific Decadal Oscillation. During the cooler regimes, increased phytoplankton productivity caused by nutrient-rich upwelling at the ocean’s surface causes the waters of the California Current to take on a greener hue. Warmer, less productive waters tend to have a deeper blue color.”
This does not mean blue waters are “bad.” It just means that some wildlife like green waters more than blue ones. In fact, a different set of marine animals thrives in blue sea conditions. Seabirds such as murrelets and albtrosses, northern anchovies, and salmon prefer colder green seas while Pacific mackarel, yellowfin tuna, sunfish and moon fish prefer warmer blue ones.
For more information: oceanview.pfeg.noaa.gov/gsbs/