Scientists are predicting a 60-65% chance of an El Nino forming this year in the Pacific. Experts are still undecided on the strength of the event. Whether you welcome or fear the effects of this weather phenomenon, an El Nino can bring some changes to the ocean that directly effect diving.
1) In simple terms, El Nino is a warming of the Pacific Ocean surface temperatures from the Equatorial Current that expands and moves north, displacing the cold, nutrient rich Humboldt Current for a period of time lasting from months to, in some events, years. The first effect divers experience is warmer, more comfortable diving conditions. With diving temperatures in Southern California typically in the mid to low 50’s, El Nino can bring surface temps into the low to mid 70’s making for very pleasant conditions.
2) Warmer water temperatures often also bring marine life commonly associated with dive trips to more tropical locales. Very recently there have been photos of Hammerhead Sharks, Ocean Moonfish and Yellowfin Tuna off the Southern California coastline. In past events divers have encountered Green Sea Turtles, Mahi Mahi and even Sea Horse at various parts of the California coastline.
3) When the cooler ocean temperatures move north, so do many of the creatures we are accustomed to encountering. When the Anchovies and Squid move north, the Halibut, White and Black Sea Bass, and even the birds follow them. In past El Nino events, divers in Southern and Central Oregon reported sighting Barracuda and Mola Mola. In the last event fisherman and free divers off of the coast of Washington were commonly encountering Blue and Striped Marlin.
4) Various species of phytoplankton create a small chemical reaction, called bioluminescence, that when disturbed glows with a green or blue color. It actually can occur in just about any ocean in the world, but scientists have found that 71.5 degrees f. to be the optimum temperature for the brightest and longest lasting glow. In previous El Nino events, divers off the coast of Catalina Island reported being able to follow their buddy in the dark without the use of a light simply from the glowing light trail from their partners fins.
5) Southern California is known for it’s abundance of Giant Kelp. Giant Kelp is the largest and fastest growing of all types of seaweed, often growing as much as 2 feet in a single day. It has been compared to what it would be like being able to dive in a forest above water. It offers shelter to many species of marine creatures from Giant Kelpfish and Kelp Bass to Norris’ Top Snail or Kelp Crab. When the ocean temperatures warm up the Giant Kelp begins to die off, thinning or even eliminating the Kelp Forest.
6) El Nino can bring an increase in rainy and sometimes stormy weather in California which, in turn, decreases the number of days divers can safely enjoy their pastime. In moderate to strong events the storms can bring destructively high surf and turbulence in the water that makes diving unpleasant, if not dangerous. Near populated areas, the runoff from storms often dumps directly into the ocean, making bacteria levels unsafe for swimmers, surfers and divers.
The El Nino temporarily alters the weather and climate patterns around the globe in both positive and negative ways. For the scuba diver along the US Pacific coast it is just another facet of one of the most diverse and exciting environments for scuba on our planet.