By Julianne E. Steers
Tiered with a canopy and several layers below are kelp forests. Located in temperate waters around the world, yet iconic to our Eastern Pacific coast, Giant Kelp (Macrocystis pyrifera) thrive in cold, nutrient-rich waters growing over two feet each day in optimal conditions. An alga, rather than a plant, kelp is not anchored by roots. Instead, it attaches to the rocky bottom via holdfasts. Like plants, however, kelp harvest the sun’s energy through photosynthesis. To remain upright and grow toward the water’s surface, each kelp blade includes a gas-filled pod that floats, building a three-dimensional habitat for more than 800 species to live within.
In the past, our coastline was cushioned by a velvety forest of kelp so dense that we would harvest kelp ad nauseum for many goods. It seemed we had an endless supply. In recent years, our waters have morphed, as well as our dense forests. While more than a singular factor may contribute to this decline, the primary culprit is global warming. These giant algae need to be bathed in cool, nutrient-rich currents to thrive, yet regional warming in recent decades has warmed our sea consistently to a devastating effect, wiping out kelp forests one by one. Warming waters have also boosted populations of invasive algae and, in some cases, predatory urchins, which feast upon kelp, compounding the decline.
These ecosystems provide essential benefits: They cleanse the water by absorbing excess nutrients, sequester carbon dioxide to drive down ocean acidification, produce oxygen, and are essential for buffering coastlines against storm surges and sea-level rise. With the capacity to draw carbon dioxide from the atmosphere, we think of terrestrial forests, whereas their ocean cousins below play an integral role. All in all, a kelp forest’s valuable marine ecosystems are a key factor in maintaining balance. With fronds like these, a piece of the climate solution is within reach.
A batch of kelp is thrust from its anchorage and lands onshore with each summer swell. Such is a cyclical process, as nutrients naturally break down and return to nourish the earth, whether on the shore or out to sea. Without an influx of stable, cool waters in the fall, our forests are unable to sprout. Even at reduced capacity, kelp must blanket the reefs to continue the cycle. Our way of life, our everyday, all those things are intimately tied to kelp forests.
Julianne Steers is a marine biologist and conservation photographer. She has an extensive background in ecology, and has been researching, diving and exploring the local ecosystem and beyond to sustain the natural world.
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