That dark mass floating on the ocean’s surface isn't oil, it's kelp

I met a young man recently who was interested in finding out more about that “weird-colored stuff” he noticed offshore. He wondered whether it was patches of crude oil from the Refugio beach oil spill.

I explained that while we are seeing small globs of fresh oil on Cambria beaches that may be from the spill more than 100 miles south of here, the brownish-green masses he was referring to are actually kelp forests growing lushly off the coast.

Those of us who grew up on the Central Coast have memories of kelp from when we were children, gleefully stomping on kelp bladders and swirling semi-dried “whips” across the sand. If you are a beach walker, you know that piles of kelp on the beach provide breeding grounds for gazillions of kelp flies. Savvy sunbathers place their towels upwind of decomposing kelp wracks for this reason.

Kelps, also known as seaweeds or algae, are not technically plants, but they fill the role of plants in the ocean ecosystem.

Our kelp forests are made up mostly of two species: giant kelp and bull kelp. For the beachcomber’s identification purposes, giant kelp has small, slippery bladders that are fun to pop, and bull kelp has long, whip-like hollow tubes that end in a round ball. Both bladders and balls are filled with gas so they float, bringing leaf-like fronds to the ocean’s surface. What we see from shore is the top, or canopy, of kelp fronds fanning out on the water, buoyed by gas-filled air bladders. The canopy can get so thick that birds can stand on it.

Kelp absorbs nutrients from the water and uses nature’s process of photosynthesis to convert energy from the sun into carbohydrates, which are used to build new fronds. June’s long summer days stimulate growth to more than a foot per day. Root-like structures attach to rocks and act as holdfasts, preventing the kelp from drifting away.

Mineral-rich kelp is harvested as food for humans and animals, and is considered a renewable resource. Kelp-based fertilizer is available in many nurseries. Giant kelp contains a natural compound called algin that gives it a slippery feel. Algin adds a creamy texture to some of our everyday products including ice cream, salad dressing and toothpaste.

Kelp forests provide food and shelter for marine organisms such as abalone, snails, kelp crabs and sea urchins. They also calm nearshore waters. On a windy afternoon, it is easy to see where the whitecaps stop at the kelp line, creating calmer waters close to shore. Kelp absorbs carbon dioxide and releases clean oxygen into the atmosphere. Kelp forests provide protection from predators for sea otters and fish.

Kelp forests cover a small percentage of the world’s oceans. They are limited to shallow, cool and clear coastal waters, exactly what we have on our coast. This is why visitors may not be familiar with them and wonder what they are. Kelp forests are part of what makes our coastline a special place.


Photo: A line of kelp is visible on the water in this photo taken June 1 at Pico Creek in San Simeon. Kelp absorbs carbon dioxide and releases clean oxygen, and kelp forests offer sea otters and fish protection from predators.
MICHELE ROEST — Special to The Cambrian

View original article at: That dark mass floating on the ocean’s surface isn’t oil, it’s kelp



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