What do you imagine when you think of World Oceans Day? Have you ever wondered what plants live in the ocean, how they survive in saltwater, or asked yourself “what are some plants in the ocean that act as the lungs of our planet”? Then look no further. Here are six extraordinary species mapping out the diverse types of plants in the ocean:
Giant Kelp (Macrocystis pyrifera)
Growing up to 2 ft (60 cm) per day in cold, nutrient-rich waters, these massive brown algae form dense underwater forests, providing critical shelter, nurseries, and foraging grounds for thousands of marine species, from sea otters to gray whales.
Neptune Grass (Posidonia oceanica)
Unlike seaweeds, seagrasses are true vascular ocean plants, meaning they have roots, produce flowers, and absorb nutrients through a root system. Native to the Mediterranean Sea, the neptune grass forms sprawling meadows and absorbs carbon dioxide up to 15 times faster than tropical rainforests.
Red Mangrove (Rhizophora mangle)
While primarily recognized as coastal trees, red mangroves are highly specialized salt-tolerant plants completely adapted to growing directly in seawater. Their iconic, arching prop roots filter out up to 99% of salt, protect vulnerable coastlines against destructive storms, and serve as habitats for young coral reef fish.
Sargassum (Sargassum natans)
Most seaweeds anchor themselves to the ocean floor, but sargassum spends its entire life floating freely on the open sea. Held up by tiny, gas-filled bladders that resemble berries, mats of sargassum stretch across the Atlantic, acting as rafts for young sea turtles, crabs, and fish.
Red Dulse (Palmaria palmata)
Red dulse is a nutrient-rich red alga found along the northern shores of the Atlantic and Pacific. For centuries, coastal communities have harvested this vibrant seaweed, which clings to rocks and kelp stems, as a natural source of iron and iodine.
Marine Diatoms (Bacillariophyceae)
Diatoms are single-celled, microscopic algae that form a core component of marine phytoplankton. What makes these tiny organisms so wonderful is their cell walls, which are crafted out of pure silica, essentially living in microscopic glass houses. Diatoms generate a significant portion of the air we breathe and serve as a food source for marine life.
Marine plants and algae face severe threats from pollution, coastal development, and environmental changes. Our health depends on their health—and their health depends on us. By saving beautiful underwater landscapes, we are securing the very air we breathe, stabilizing our climate, and feeding the marine ecosystems that keep our planet alive.
