By Brett Warnke
The ocean water is getting warmer. But our kelp like the cold. So what, right? The fly-blown smelly kelp ruins the beaches, anyway! Well, the precious kelp is a temporary ecosystem. Our species in Southern California, the Giant Kelp, needs to live or else an entire ecosystem will be disrupted. This “foundational species” then needs less heating, not more and if nothing is done their numbers will degrade with terrible results for life beneath the sea.
Lais Lima is a doctoral student at SDSU’s Dinsdale Lab. She has spent time diving in the waters around Point Loma, down in the cool waters our kelp love so much. But Scripp’s recently recorded the highest-ever seawater temperature of 78.6 degress, following a series of individual daily records of sea-surface and seafloor temperatures. In Lima’s beautiful dives around LaJolla and Point Loma she has seen a change in the temperature of the water, the thermocline.
“I went to La Jolla Cove and there was no thermocline,” she said. “It was hot all the way down to the bottom. When you go 40-60 feet down the temperature is supposed to suddenly drop. Kelp is relatively protected by cold waters on the bottom. But the surface waters are very, very warm.”
In the spring there are lots of winds and colder waters rise to the surface. The kelp love this and flourish. They increase their population, growing denser and releasing kelp babies called “recruits.” In the summer it is normal to have decreases in the population as waters get warmer. This is why you will see the tangles of kelp on the seashore, they are not in their ideal condition.
But so what?
“Like other climate change trends, background warming enhances the probability and magnitude of extreme events,” said Scripps oceanographer and Shore stations principal investigator Reinhard Flick.
Without a cool water buffer, kelp are in trouble. Consequently, all coastal fish species here that depend on kelp are in trouble, too. The black or Giant Sea Bass, already a critically endangered species, relies on kelp, as do abalone and groupers.
“For animals that need skeletons or a shell, more acidic waters disrupt the process,” Lima said. “This makes shelled animals like abolone more exposed because they’re unable to create a shell hard enough to protect them.”
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