During the summer of 2014 the ocean off the coast of southern California warmed to an unusual degree, the cause of which was largely undetermined. There was no official El Niño, the most common culprit, nor any other reasonable explanation. And unlike other warming events, the water along the coast has stayed unseasonably warm since then.
Normally the summer months bring warm waters to the southern California coast. These warm conditions persist through the fall and into early winter, only being disrupted by the occurrence of winter storms that are powerful enough to churn-up the layer of warm water at the surface, mixing it with deeper, nutrient-rich water that will fuel the explosion of life in the spring. But with California locked in conditions bringing severe drought, the powerful winter storms didn’t materialize this past winter.
While such warm water events do occur here from time to time and bring with them surprise visits from any number of tropical species, they also have a negative impact on the local ecosystems. Forests of giant kelp (Macrocystis pyrifera) are typically hard hit by warm waters are stripped of the vital nutrients that kelp and all other algae need to grow and survive. Lacking algae that provides cover and food, the rest of the food web is also impacted.
Add to these conditions the presence of an invasive algae species introduced to the waters of southern California in 2003, and you have a recipe for potential major ecological changes. The invasive algae, Sargassum horneri, is native to waters around Japan and Korea, and has proven to be quite capable of rapidly reproducing in the waters off southern California, and today has been documented to occur from Santa Cruz Island in the Channel Island archipelago in the north to Isla Natividad in Baja California, Mexico in the south.
The ultimate impact on giant kelp forests is uncertain. The loss of giant kelp within its normal range has been dramatic, which is not unusual, but how well it is able to make a comeback in the face of an intruder that takes over and occupies the same habitat the kelp prefers remains to be seen. And now with the National Oceanic and Atmospheric Administration of the United States government officially recognizing El Niño conditions in the tropical Pacific Ocean, the warm water conditions may persist for quite some time.
But there is some cause for hope. Giant kelp is returning to places it has historically been found. Today’s photo was taken in Lobster Bay on the backside of Catalina Island on May 30, 2015, and other sites also showed the presence of giant kelp.
Today's photo was made with a Canon 8-15 mm f/4L fisheye lens mounted on a Canon 5D Mk. III in an Ikelite underwater housing. It was illuminated by two Ikelite DS-161 strobes and two Ikelite DS-125 strobes in manual mode. The exposure was set to 1/60 sec at f/6.7 and ISO 200.