California Kelp Chat With Dr. Mark Carr

You can think of kelp as the rainforest of the ocean. It’s second in productivity only to bamboo. As its leaves fall to the ocean floor, it provides nutrients and serves as the foundation that hundreds of different species rely on.
But this ecosystem is falling out of balance because of warmer ocean temperatures. Ocean temperatures have been rising gradually for decades with occasional spikes known as marine heat waves. During these events, there is less upwelling and the water is nutrient-poor. This is bad for kelp, which likes cold, nutrient-rich water. Growth and reproduction become difficult for the kelp, and fewer leaves fall to the ocean floor.
This is where the real trouble begins…
Normally, purple urchins, which are a native species to California, feed on the fallen kelp leaves, but when that food source is gone, they go crazy and start to eat the kelp itself. They basically kill the goose that lays the golden eggs. You might think that once the entire kelp forest is wiped out, and turned into what is called an urchin barren, the urchins would run out of food and die… but they don’t. It’s almost like they turn into little zombies, reducing their internal organs, but stay alive just enough to hold onto the real estate that the kelp might try to move back into.
So if the urchins won’t die, do they at least have some predators?
This is where the trouble continues…
The two main predators for purple urchins are the sunflower sea star and otters.
But since 2013, the sunflower sea star has been almost completely wiped out by the sea star wasting disease. And while the otters will eat the urchins in healthy forests, helping to manage the ecosystem there, the “zombie urchins” in the barrens aren’t even worth eating. In other words, otters are picky eaters.
So why is this important?
There are many reasons, but we’ll focus on three…
1) Biodiversity. As previously stated, kelp forests are like the rainforest of the ocean. It plays a crucial role in the lifecycle of hundreds of species, so to lose kelp would mean a reduction in biodiversity across the board.
2) Human Impact. If less kelp means fewer fish, this can impact the recreational and commercial fisheries, and in some cases already has.
3) Climate change. Through photosynthesis, kelp turns CO2 into oxygen, so a reduction in kelp means an increase in greenhouse gases, which would warm the ocean more, leading to a further reduction in kelp… a classic positive-feedback-loop working in a negative direction.
Fortunately, it’s not all bad news…
Great research is being done on this topic, and plans for restoration are already underway.
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#california #kelp #centralcoast #climatechange #ocean

[@f.n.schlub2269]

@Holt Hanley -- It is refreshing and hopeful to hear discussion of this aspect of our ecology.

[@robertforrest7956]

So many don't understand how Vital this whole ecosystem is!!

[@nulucid]

It's called ongoing Fukushima core meltdowns raging in the Pacific.

[@gurkengamingpvz21]

Haven't heard of that

[@nulucid]

@@gurkengamingpvz21Maybe because it's greatest cover up in human history.