Bringing seaweed to the surface reveals its intense colors and complex shapes.
Seaweed feels the full brunt of an “out of sight, out of mind” mentality. For many, the only time they notice the sea-dwelling flora is when they feel its tingly, slimy embrace while swimming close to shore.
But seaweed is far more complex and beautiful than it's given credit for.
Artist and avid beachcomber Joise Iselin fell in love with seaweed’s intense colors and complex forms. She collected more than 200 specimens from tidal pools along the California and Maine coasts, and produced portraits of them using a flatbed scanner. In her new book An Ocean Garden, she tells the story of some of her favorites.
Pictured: Bonnemaisonia californica
Color is perhaps a seaweed’s most striking characteristic. When held up to the light, the intensity of its magenta, the subtlety of its golden brown, or the clarity of its kelly green can take your breath away.
William Henry Harvey, a colorful Irishman who traveled the nineteenth-century world collecting specimens, became the father of modern-day phycology, that arm of botany that studies marine flora. Harvey was the first to use color as the basis for identifying seaweeds.
Pictured: Delesseria sanguinea
A seaweed’s color is determined by the combination of pigments housed in its chloroplasts or plastids (a specialized substructure within its cells).
Green algae (phylum Chlorophyta), like plants, have chlorophyll a and b in their chloroplasts. They are, in fact, typically green.
Pictured: Scytosiphon lomentaria
Brown algae (class Phaeophyceae), which include kelps and rockweeds, have a third, brown accessory pigment that, when combined in different amounts with the green chlorophyll, creates their array of colors.
Browns can range from olive green to golden brown to yellow-orange.
Pictured: Desmarestia herbacea (Acid kelp)
The six thousand or so species of red algae (phylum Rhodophyta) have red and blue accessory pigments that overshadow the single chlorophyll a pigment.
When these pigments combine, the color can be dazzling: striking scarlet, maroon, pale pink, or deep purple.
Pictured: Polyneura latissima
What a strange creation this kelp is. Like a bizarre feather boa, its paddle-shaped blades line the edges of a straplike midrib covered with tiny spikes.
Intermittent rounded bladders, sporting whimsical, winglike blades, help to keep the massive rope afloat in its subtidal life, to catch the sun’s rays and perform the work of photosynthesis.
Pictured: Egregia menzieseii (Feather boa kelp)
Macrocystis pyrifera, the amber giant of the kelp forests, is the most romantic of seaweeds.
Its blades adorn advertisements for high-end hand cream, and it’s not a gimmick. Seaweed derivatives, such as the phycocolloid called “alginate,” made from the cell walls of Macrocystis, have long been the emulsifying agent in skin-care products.
But today, seaweed in toto is used as the active ingredient in many health-enhancing body lotions.
Pictured: Macrocystis pyrifera (Giant kelp)
The bryozoans clearly love their seaweed. Hitching a permanent ride on kelps and other seaweeds has many advantages for these tiny animals.
The constant motion provided by the host not only provides added access to food particles, but also a defense against predators. Living right on an oxygen source, with each cell of kelp exhaling oxygen ready for the animal’s respiratory needs, is also a bonus.
Pictured: Palmaria palmata (dulse) with bryozoan colony
Wakame is the Japanese common name for Undaria pinnatifida.
Undaria is native to the seas of Japan and Korea, and it has been harvested there for centuries. In Korea, Undaria soup is served to new mothers for the two weeks after they give birth, the vital minerals passing to the new baby via breast milk for an auspicious beginning.
Thereafter, it is served on birthdays as a reminder and celebration of this healthy and lucky first food.
Pictured: Undaria pinnatifida (Wakame)
While some beachcombers might turn up their nose at a slimy piece of seaweed on the beach, they should not.
Irish moss is famous for setting the frothy New England fanciness, blancmange, when boiled in milk, and what keeps seaweeds flexible and slippery is also what keeps ice cream, lipstick, and shaving cream smooth.
Pictured: Chondrus crispus (Irish moss)
Sign up to get the latest science news delivered weekly right to your inbox!