Some pieces stretch for meters, still tangled with small shells and bits of driftwood, while others hold tight, bulbous floats that once kept them buoyant in the underwater forests just offshore.
When the tide recedes, the air fills with the unmistakable scent of iodine and salt—an ancient perfume carried by the sea.
Kelp is a brown alga, part of the group Phaeophyceae, which evolved roughly 150 to 200 million years ago.
While kelp itself doesn’t fossilize easily (it’s soft-bodied and decomposes quickly), its ancient lineage can be traced through molecular and microfossil evidence. The earliest relatives of kelp likely appeared in the Jurassic seas, when dinosaurs ruled the land and the oceans teemed with ammonites.
Microscopic spores and chemical biomarkers in sedimentary rocks tell scientists that brown algae were already photosynthesizing in shallow coastal waters long before the first mammals appeared.
These towering underwater forests provide shelter and food for thousands of marine creatures, from tiny snails to sea otters, who wrap themselves in the fronds to sleep without drifting away.
Back when I used to scuba drive a lot around Vancouver Island, they were one of my favourite places to explore as those underwater forests were teeming with life.
If you’re beachcombing in British Columbia, Alaska, or California, you might find bull kelp, Nereocystis luetkeana, recognizable by its long, whip-like stipe and single round float. It’s edible and surprisingly tasty. The blades can be dried and used like seaweed chips, while the bulb can be sliced thin and pickled—an oceanic delicacy with a salty, citrusy crunch.
Other edible seaweeds you might encounter include sugar kelp, Saccharina latissima, which has a slightly sweet flavor, and ribbon kelp, Alaria marginata, often used in soups and salads.
On the foreshore near where I live on Vancouver Island, we have loads of sea lettuce. Sea lettuce, Ulva spp., is one of the ocean’s most vibrant and inviting greens—a delicate, translucent seaweed that looks like bright green tissue paper fluttering in the tide.
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| Sea Otter in a Kelp Bed |
Its thin, ruffled fronds are only a few cells thick, soft to the touch, and often cling to rocks, shells, or docks in intertidal zones where saltwater and freshwater mingle.
Unlike the giant brown kelps that form towering underwater forests, sea lettuce is part of the green algae group (Chlorophyta), sharing pigments more closely related to land plants.
It grows worldwide in temperate and tropical waters and thrives wherever nutrient-rich water flows—estuaries, tide pools, and shallow bays. When the tide goes out, you might see it draped over rocks like sheets of emerald silk, drying slightly in the sun and releasing a faint, oceanic scent.
Sea lettuce is entirely edible and a favourite among foragers and coastal chefs. Fresh from the sea, it has a mild, slightly salty flavour with a hint of sweetness—similar to spinach or nori. It can be eaten raw in salads, lightly fried until crisp, or dried into flakes and used as a natural salt substitute.
In many coastal cultures, from Ireland to Japan, Ulva has long been part of traditional cuisine. It’s also rich in vitamins A, C, and B12, along with iron and calcium—proof that sea greens can be as nutritious as they are beautiful. When my little sister was living in County Cork, she shared pictures of folk bathing in tubs of icy sea water and seaweed as a briny health spa treatment.
From a scientific perspective, sea lettuce plays an important ecological role. It provides shelter for small marine creatures like snails, shrimp, and juvenile fish, and it helps absorb excess nutrients from the water, which can help reduce harmful algal blooms.
However, when too many nutrients enter the ocean—often from agricultural runoff—sea lettuce can grow explosively, creating dense “green tides” that blanket shorelines.
Its lineage stretches deep into the fossil record as well. While soft-bodied algae like Ulva rarely fossilize, green algal relatives appear in rocks over 1.6 billion years old, making them some of Earth’s earliest photosynthesizers.
Beyond their culinary and ecological roles, kelp forests act as powerful carbon sinks, pulling CO₂ from the atmosphere and storing it in the deep ocean. They also buffer coastlines from storms and provide nurseries for fish populations that support global fisheries.
As you stroll the shoreline and your toes brush against that slippery tangle of golden-brown ribbons, remember—you’re touching the living descendant of an ancient lineage that’s been swaying in Earth’s oceans since the age of dinosaurs—beautiful, ancient and tasty!
