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Sea lions, blooming algae, and flushable kitty litter
Observations from the Edge
Robert T. Nanninga
May 1, 2002
"One of the great dreams of man must be to find some place between the extremes of nature and civilization where it is possible to live without regret." — Barry Lopez
Recently Californians have been witnessing a slice of life not found within the convenient comfort of the Discovery Channel, Animal Planet, or "When Animals Attack." This alternate universe, the one not provided by television, is one where the biggest threat to wildlife is not other animals, but the smart monkeys clutching the remote.
The latest canary in the proverbial coalmine, Zalophus californicus, the California Sea Lion has been found along the coast, dead and dying, victims of a toxic food chain. No one is certain what set this chain of events in motion, consensus is the toxic event is directly related to a temperature increase. According to the marine biologist I spoke with at the Hubbs Research Institute, the warming trend maybe actually part of an acceleration of the El Nino climatic patterns.
On Beltane, I started the morning with a call from an Encinitas resident who was concerned for an ailing sea lion on the beach beneath his bluff top home. Mixed with his obvious frustration over not being able to help the unfortunate animal, was anger over an apparent lack of interest on the part of those he thought in the best position to help. Having watched the animal suffer since sunrise, the second time he called was to inform me there was still no sign of Sea World and that sea gulls were already congregating for the impending buffet. Hardly the picture postcard the Chamber of commerce wants the world to see.
As is most matters of kismet, I was already "in my head" over the recent sea lion die off, as my editor had requested I turn my attention in that direction. What I discovered was that the reason for the dead marine mammals organic in nature, although the jury is still out over just how natural this lethal algae bloom is. Pseudonitzschia, the toxic diatom, during certain stages produces a deadly biotoxin that can potentially affect entire ecosystems.
Marine mammals and sea birds that feed on anchovies and other filter feeders, which are ironically unaffected by the poisonous bloom of the diatom, fall victim to domoic acid attacking their central nervous system which results in brain lesions and ultimately death. The link between sea lion fatalities and toxic algae was discovered after biologist began looking for answers after the deaths of more than 400 sea lions during May and June of 1998. When autopsies of the pennipeds found Pseudo-nitzschia in feces of deceased sea lions and domoic acid in the animals' urine, feces, and serum. Similar deaths have also been recorded in dolphins, humans, and other marine mammals.
Knowing how these animals are dying does little to answer the bigger question of why. Something tells me that there is more to the equation than blooming algae, as algae has always bloomed in the Pacific, and sea lions up to this point, have evolved in spite of toxic anchovies. The question is what else could be contributing to this new threat against oceanic biodiversity, and is this just the beginning of a much bigger catastrophe?
Researchers from UC Santa Cruz and San Francisco State University studying the environmental conditions surrounding toxic algal blooms have discovered that urban and agricultural run-off boosts the growth of the common red tide algae, Lingulodinium polyedrum, uses organic urea (read Human urine) as a nutrient source. Although not toxic red tides do result in oxygen depletion, suffocating marine life unable to flee the decomposing organic matter.
The algal bloom killing sea lions has yet to be traced to urban runoff, however Pseudo-nitzschia which is spread naturally via ocean currents may be more likely to explode into bloom if they wind up in polluted waters. The science is still out. One thing we do know is that human generated pollution serves no beneficial purpose, other than short term economic gain of those responsible.
Speaking of human induced marine mammal die offs, flushable cat litter has recently been identified as the likely link between a specific bacteria and protozoa commonly found in cat feces, and sea otter fatalities. With less than 2000 California sea otters left in the world, it's depressing to think a species nearly hunted to extinction at the beginning of the last century will more than likely succumb to cat poop at the beginning of this one.