Eelgrass is 1 of 60 species of seagrasses of the genus Zostera found in shallow coastal areas worldwide!
- Since the time of the dinosaurs, three groups of flowering plants, or angiosperms, dominated the oceans. Known as seagrasses, these are the only flowering plants that can carry out their entire life cycle underwater. Seagrasses are not true grasses, such as those you would see growing in on land. However, because they grow in large meadows and move and sway with the currents, many species of seagrass look similar to land grasses and so have been called seagrasses.
- If it’s not seaweed and not grass…what is it? Long ribbon-like blades, which give eelgrass its name, require much light to perform photosynthesis and are generally confined to water less than 8 feet deep but may occur at depths up to 100 feet or more in exceptionally clear water. Eelgrass is neither a true grass nor a seaweed, such as kelp, but a flowering plant that grows entirely submerged in water and has a stem, roots, and produces a seed.
Where Does Eelgrass Grow?
Eelgrass (Zostera Marina) grows in coastal waters worldwide from Alaska in the Northern Hemisphere all the way down to Australia in the Southern Hemisphere, in the Chesapeake Bay, off the coasts of Florida, California, and coastal areas of Europe and Asia. Eelgrass is found in estuarine and marine environments, such as estuaries, bays, and at entrance channels leading to the ocean. Most seagrasses live either completely submerged, but some are able to tolerate exposure during low tides. Seagrasses anchor to the sediment through roots and rhizomes; through the growth of the rhizomes and roots, they may form dense “beds” of individual plants.
- LOTS OF LIGHT (approximately 20-25% of light hitting the surface of the water)
- Moderate wave disturbance and good tidal flushing
- Firm sand to soft mud
- Depths ranging from -1ft to -8ft MLLW up to 100 feet deep in very clear water
- Cool and clear waters (ideally between 10°C and 20°C)
Eelgrass as a Habitat
Eelgrass meadows are often compared to tropical rainforests and coral reefs as they are known to be one of the most highly productive and biologically diverse habitats on earth. Eelgrass supports infauna (organisms living within the sediment) and epifauna (on or above the sediment) and because eelgrass habitats support so many organisms, it is considered that eelgrass habitats have three distinct ecosystems: subbenthic, benthic/demersal, and the canopy.
Very few organisms actually consume eelgrass due to the high cellulose content, but they are mostly consumed after being decomposed into detritus. Detritus are organic materials for detrivores such as infaunal worms and crustaceans which in turn are consumed by larger consumers, thus creating what we call a detrital food web.
Photos by Seagrass Li
- Caulerpa taxifolia page, UC Davis
- City of Newport Beach- Caulerpa
- The Seattle Times: Global Warming May Impede Eelgrass Growth
- Seagrass LI