Stay Cool, Breathe Easy – the Blues are Back in Town!
The day began at dawn, with seabird nesting in full swing. Pt. Blue Conservation Research biologists were hard at work in the Farallon Islands National Wildlife Refuge off San Francisco, the largest seabird rookery in the “Lower 48” states. This archipelago is the exclusive domain of wildlife, drawn there because of its situation in one of the richest ocean regions on the planet, NOAA’s Greater Farallones National Marine Sanctuary in the California Current Ecosystem.
A small, dun-colored seabird’s unusually early and remarkably successful breeding season this spring had drawn the scientists’ attention, for Cassin’s auklets’ small bills allow them to eat only the smallest prey: krill. Tiny shrimplike crustaceans, krill are living energy packets and a keystone species in the ocean ecosystem. Clearly, it was plentiful, and when that occurs, blue whales, at the extreme end of the size spectrum, may show up, too. Indeed, on June 13, an astounding aggregation of over 47 blues were suddenly sighted from Southeast Farallon Island, their steel gray-blue backs stretching as far as the eye (aided by spotting scope) could see. They dove repeatedly, powerful flukes propelling their 150-ton bodies deep into thick layers of krill which they engulfed. Surfacing to breathe, one whale exhaled a high columnar blow of air and mist nearly 30 feet tall; simultaneously, it ejected a bright reddish-orange “fecal plume.” In short, it pooped prodigiously in the sunlit sea.
This feast of the masses is possible only in a healthy marine ecosystem, unspoiled by oil drilling, dumping, and other degradation. This state of affairs, and the area’s incredible capacity for sustaining a huge biomass of sea life, is not accidental. The Greater Farallones sanctuary lies adjacent to an urban center of eight million people, with industry, shipping, discharges and other infrastructural elements. The sanctuary’s work of nearly 40 years has been to ensure the soundness of the ecosystem by protecting its habitats and its creatures, blue whales, for instance. But what do they do for us in return?
SUPERSIZED FOODIES: Whales consume vast quantities of fish, squid, krill and other prey. But we humans often harvest these same species for our own needs. So, if we kill the whales, won’t there be more seafood for us? Such was the thinking in past centuries, but that logic was flawed. Turns out, when whales were hunted out of an area and their predatory pressure on krill and small fish removed, instead of rebounding, the fish and krill disappeared, too. What was going on?!
ANYONE GOING DOWN? Most whale species feed in the water column, diving up, down and sideways through layers of krill, and schools of fish. Some feed in the night-dark depths at nearly 10,000 feet. Their prey contains nitrates and iron, essential elements in photosynthesis. But photosynthesis cannot take place in the dark.
GOING UP! As air breathing mammals, whales must surface into the photic zone where sunlight penetrates, to fill their lungs with sweet, life-giving oxygen. As they rise, their flukes (tail) propelling them, they stir up nutrient-laden water. A whale’s repeated dive-surface sequences create a piston-pumping action that results in vertical mixing of the waters and its suspended nutrients. The “fertilizer” becomes accessible to tiny marine algae which, when sunlight reaches them, burst into profuse life. Plant plankton absorbs carbon dioxide (CO2) from the atmosphere, a major factor in greenhouse gas-related climate warming. And marine plants’ photosynthesis produces the oxygen we breathe—more, in fact, than rainforests. When the algae die, they sink to the sea floor, carrying with them carbon that remains there for millennia. But some are eaten by zooplankton – tiny ocean animals like krill – and larger creatures like fish and whales eat krill. And, when whales approach the surface, voila! They’ll often evacuate - copiously. More fertilizer for the sunlit ocean garden!
So, whales nourish the marine food web that culminates in the seafood we eat. And whales sequester CO2 from our atmosphere, helping to reduce greenhouse gases that warm our planet. Thus, whales and their poop enrich our oceans and improve our atmosphere, our climate and our lives, in fundamental ways.
More info at https://farallones.noaa.gov.
