I’m not sure what I expected when I rolled over the side of our boat to once again dive the long legs of Platform Eureka off of Long Beach. I had explored her depths before- but this time something was different…she had been ‘shaved’ down to about 65ft of all the mussels, scallops, strawberry anemones and other sessile invertebrates that had called the upper half of her home. I plunged in expecting an interesting opportunity to photograph what a ‘bare’ rig looked like in comparison to one exploding with growing life. However- I was pleasantly surprised to discover this was not the case.
A quick assessment from the surface revealed excellent visibility of at least 130 feet- judging by the fact that we could see the second crossbeam of the platform looming below us at 120 feet. Below our kicking feet, thousands of glittering juvenile jacks darted in massive schools among the beams, shifting and veering at the slightest disturbances within the water column. Though her beams were bare, they had already begun to show signs of returning life in the form of algae- and their nakedness certainly had no effect on the masses of schools among us.
Oil platforms in California’s waters are regularly cleaned, or ‘defouled’ every few years. Biological fouling, is the accumulation of microorganisms, plants, algae or animals, that grow on almost any structure submerged beneath the oceans surface for any extended period of time. Once a platform is submerged or cleaned under the water, the submerged portion is rapidly colonized by a variety of marine animals. Changes in species composition, abundance and biomass of the fouling assemblage over time is influenced by the season, water depth, location and other factors. The density of this biofouling is considerable. When platforms Helen and Herman were decommissioned off the coast of California in 1988 from the Santa Barbara Channel, a total of 900 metric tons of wet attached invertebrates were removed from the structure (Schroeder et al 2004). In comparison, a blue whale only weighs about 181 metric tons.
The elimination of marine fouling on offshore structures typically involves the manual removal of the fouling by divers and/or remotely operated vehicles using such tools as water blasters, manual or mechanised scrapers, and ultrasonic systems. Without these regular cleanings, or scrapings, the dense buildup of mussels and other organisms on the platform’s legs could cause enough friction and drag to threaten the platforms stability in the surrounding ocean currents.
In California, mussels are one of the most common creatures to be found growing on the Oil Platform beams. Mussels are effective filter feeders, and not only clean the water, but they are also tasty. This has led to some enterprising individuals to develop relationships with the oil companies to be permitted the opportunity to clean the rigs and keep the mussels for sale. In fact mussels have been harvested by the California restaurant industry for many years.
I emerged from our dive, dripping and exhilarated, and as always, surprised by the reminder of industry humming above. The cleaning of this platform and the subsequent and voracious return of life I had witnessed only reaffirmed what I already knew about the tenacity of life. However it was a reminder for me of the inevitable will life in the ocean has to survive, no matter the home. To many, these platforms are eye sores, dirty indicators of our insatiable appetite for oil and gas, however to many scientists like myself, these platforms are a sort of biological miracle. These platforms have more to offer than just energy- their vibrant underwater communities are also a valuable source of food for many unassuming Californians in the form of commercial harvesting of the mussels, due to their predictable growth and replenishment rates. In 1994 Ecomar Marine Consulting of Santa Barbara harvested around 500,000 pounds of mussels from 12 platforms in Southern California alone. Most licensed divers know these platforms to be a honey pot of sorts, and state health officials have said that the mussels harvested commercially from them are safe to eat year-round, and are tested weekly to monitor for toxins. I myself have enjoyed many a raw scallop harvested from their beams, and I have to say, a sweeter meat I have not tasted in any restaurant.
Schroeder, Donna M., Love, Milton S. “Ecological and political issues surrounding decommissioning of offshore oil facilities in the Southern California Bight”. (2004). Ocean and Coastal Management.