Common Marine Plants of the Salish Sea
Five-ribbed Kelp, Costaria costata
This large kelp, a member of the brown algae group of seaweeds, has been abandoned by the tides. Torn from its secure site in the upper subtidal zone, it has washed ashore and begun to bleach in the hot summer sun. The holdfast that grips rocks or other hard surfaces is the small light brown branching structure at the right hand side of the plant. Connecting it to the blade is the narrow stipe. The blade contains five ribs that run it’s entire length. Between each rib is a series of puckers which remain dark brown while the tissue in between turns green as it dies.
This particular specimen is about three feet (1 meter) long and about one foot (35 cm) wide. However the plant can display a wide range of shapes and sizes depending on the time of year (it is an annual) and degree of wave exposure. This specimen is from a sheltered area and has grown wide rather than long. If it had remained attached it could have reached up to six feet (two meters) long by the middle of the summer. In areas with high water surge from large waves or high currents the plant would have been very narrow having a width some 8-10 times smaller than the length and with more prominent ribs.
This species of kelp ranges from the Aleutian Islands in Alaska to Monterey Bay in central California and is a preferred food item of sea urchins.
Crustose coralline algae
The thick red material resembling spilled paint that covers this rock surface as well as the calcium home’s of tube worms is not a coral, but a member of the red algae group. Red algae are a large and diverse group of usually soft bodied seaweed that are quite common in Puget Sound. Crustose coralline algae range from the intertidal zone to deep water (around 100 ft) from Alaska to Mexico.
There are numerous species of crustose coralline algae, but they can usually only be told apart based on microscopic examination. Their growth habit ranges from a wide spread, thick covering, like the one in the photograph, to small 1 to 4 inch patches. In addition the surface may be smooth or include knobs and plates. The color can range from whitish pink to deep purple. They are perennial, some living for a number of years. The cell walls contain calcium carbonate which gives them a hard texture and protects the plant tissue from grazing animals.
There is a related group of coralline red algae that are erect and branching with articulations between the hard segments (articulated coralline algae). They have a similar range but occur in shallower water.
Diatoms
Looking like a small brown seaweed, this mass of plant material is really something quite different. It is a colony of microscopic, single celled plants called diatoms that display a yellowish-brown color. Diatoms occur as both colonies and as single cells. You can find several types of colonies of diatoms: chains of round, tuna-can shaped individuals that form a large amorous mass (as seen in the photograph) or more organized branching filaments made up of numerous intertwined elongated individuals. They are a common plant in marine and estuarine waters (as well as in fresh water) and are an important part of the marine food chain worldwide.
The small spheres in the yellow-brown mass in the photograph are bubbles of oxygen being produced by the plant on a sunny day.
Diatoms occur as single cells consisting of cellular material encased in overlapping shells of silica called a frustule or test. They reproduce by vegetatively dividing the cell in two parts, each of which uses half of the old test. Since one half of the test is smaller than the other half, each successive generation is partly smaller than the original cell. When a minimum size is reached, sexual reproduction occurs forming an auxospore which expands to a larger size.
According to Thomas Mumford, senior marine scientist with the Washington Department of Natural Resources, chain forming diatoms are common in the spring and fall when they will coat some sandy and muddy beaches – growing faster than they can be eaten.
Green String Lettuce, Enteromorpha intestinalis
There are two kinds of common green seaweed in the photograph. Floating above the wide green blades of sea lettuce is another green algae called the Green String Lettuce. It consists of narrow hollow tubes made up of a single cell layer. The color ranges from white to yellow to green. The white color is due to bleaching of the blades at the water surface. Bubbles of oxygen within the tube formed from photosynthesis in the algae is causing the blades to float.
This plant grows in a wide range of conditions from very low salinity conditions to highly saline pools found at the extreme high tide level. Because of its tolerance of freshwater it can be used as an indicator of shoreline seeps caused by groundwater or leaking septic tanks.
It is found around the world in the mid to high intertidal zone. It ranges from Alaska to Mexico on the Pacific coast of North America.
Green String Lettuce is eaten in Asia. Nutritionally it contains about 20 percent protein and is low in fat and sodium while high iron and calcium. Its vitamin B content is generally higher than most vegetables. The vitamin A is high, but it is only half of that found in spinach.
Rockweed, Fucus spiralis
This species of seaweed and it’s close sibling, Fucus gardneri, (both called rockweed) are very common in the mid to high tide zone throughout Puget Sound. They are members of the brown seaweed group called Phaeophyta to which the kelp also belong. The inflated bulbs at the end of the blades along with a midrib in the blade are major distinguishing characteristics of rockweed. The bulbs are filled with air and mucilage that allows the blades to float exposing them to sunlight and allowing water to move through the branches.
Gardneri is very similar to spiralis but lacks the thin flange ringing the inflated bulbs as seen in this photograph and has a more prominent midrib. Spiralis, which occurs higher in the intertidal zone than does gardneri, ranges from the Aleutian Islands south to Washington. Gardneri occurs throughout the same area but continues into southern California as well.
The bumps on the bulbs are reproductive structures called pits or conceptacles. Special cells within the pits produce eggs and sperm which are released into the water column and fuse producing a baby plant. The new plant then grows directly into an adult. Reproduction occurs through the year. Other seaweeds have a more complicated reproduction cycle where one form produces eggs and sperm while another form produces spores.
Rockweed was once used by humans for cattle fodder and mulch but is not used today. However it serves a significant function as habitat for a variety of animals at all stages of the tide. Periwinkle snails and small crustaceans hide among the branches when the tide recedes while small fish move into the branches to feed at high tide.
Sugar Kelp, Laminaria saccharina
This large brown seaweed or kelp, like other kelp species, consists of a large flat “blade” and a short round “stipe” that connects to blade to the “holdfast” by which the plant is attached to a rock or cobble. This species of kelp can be identified by the two rows of wrinkles along the blade. It ranges from southern California to the Aleutian Islands. It occurs in the extreme low intertidal zone and shallow subtidal zone in protected marine areas.
When young the sugar kelp can grow up to 6 to 9 feet long and 8 inches wide. The blade of a young plant, such as this one, would be free of hitchhikers such as bryozoan or hydroids.
Several species of kelp are very large and dominate the nearshore area where they occur. These large species provide refuge for a wide variety of animals and plants.
The name kelp comes from the middle English word for ash. Kelp was burned to produce an ash used in the production of soap. It was also a principal source of iodine. The sugar part of the name of this species comes from the high content of mannitol which is a sweet tasting chemical.
Sugar kelp has been cultured in British Columbia as a food for farmed sea urchins whose eggs are a delicacy in Japan. Various species of Laminaria are eaten in China and Japan. In Japan it is known as “kombu”.
Kelp are members of the group of seaweeds known as brown algae which are very common in the marine environment. They are distinguished from green and red seaweeds by the presence of brown accessory pigments in addition to chlorophyll.
Sea Cauliflower, Leathesia difformis
This yellowish brown seaweed is a member of the marine algae group called brown seaweeds or Phylum Phaeophyta. The big seaweeds called Kelp belong to this same group. The Sea Cauliflower is a sack-like, multi-lobed plant that is composed of filaments and will disintegrate when pressed between the fingers. It often occurs alone as shown in the photograph or can be found in large clumps.
When young it is solid and might be confused with another brown seaweed called the Brown Bag (Colpomenia bullosa). However it hollows as it grows and retains the rough, brain-like appearance. Starting growth in late spring and finally disappearing in early fall, this two inch, average-sized specimen might attain a size of six inches in diameter .
It is common on rocks or some seaweeds and sea grasses in the mid to low intertidal zone. The species can be found in the eastern Pacific Ocean from the Bering Sea to Baja California. It is also present in Europe and Chile.
Turkish Washcloth, Mastocarpus papillatus
This species of red algae is commonly found in rocky or gravely substrate in the mid to high intertidal zone. This short bushy seaweed is around three to five inches across. Small clumps of this seaweed are widely scattered over the beach making it hard to find unless you look closely. Being so small, it shelters only a few marine snails and the occasional mud-flat crab.
The common name for this species is derived from the knobby bumps on the surface of its blades and small size which looked to an old-time marine botanist like a turkish washcloth. A larger, but related species, with a similar appearance is called a Turkish Towel.
Red algae are one of three major groups of marine algae that are commonly seen in the intertidal and subtidal zones. The other kinds are Green algae and Brown Algae. Red algae range in color from pinkish through yellow-green to dark purple. The colors derive from differing amounts of two accessory pigments, a red one and a blue one. These colored pigments mask the green color of the chlorophyll that is used to capture sunlight.
This kind of red algae along with several other species are used by humans for a variety of purposes. Most commonly the algae is harvested and processed to produce Agar. Agar is a gelatinous material used as the bacterial growth medium in science labs as well as in drugs to promote slow release of active ingredients. Agar is also used as a antidrying agent in baked goods and as a thickening agent in soups, sauces, salad dressing, jellies, and ice cream. Agar is also used in cosmetics, lotions, and shaving cream.
Rainbow-leaf Seaweed, Mazzaella splendens
The large seaweed blades in the middle of the photograph belong to a common intertidal inhabitant of protected rocky shores called the rainbow-leaf seaweed. The blade color is a deep reddish purple. In the field (but just barely seen in the photograph) the surface of the blade has an iridescent sheen or rainbow hue. This is an unusual seaweed characteristic and is a help in identification of the species. The blade’s shape can range from oval, as seen here, to narrow depending on the amount of wave exposure and type of habitat.
Found in the mid to lower intertidal and upper subtidal of rocky habitats the plant ranges from southeast Alaska to northern Baja California.
There was an experimental harvest of this seaweed in Washington in the 1970’s for it’s carrageenan content. Carrageenan is used as a smoothing and thickening material in toothpaste, ice cream and paint. There were also large-scale field experiments undertaken by the Washington State Department of Natural Resources in the culture of the species on submerged ropes in south Puget Sound. Both efforts became irrelevant when cheaper sources of carrageenan were found in other countries. However the experience left the Department with expertise in marine plants which has been maintained for 35 years evolving into a variety of programs including today’s activities associated with marine plant inventory, protection and restoration.
Bull Kelp, Nereocystis luetkeana
One of the largest of the brown seaweed group called kelp, Bull kelp can grow to lengths of around 100 feet, however the plant in the photograph is a young one only three feet long. Very fast growing, it matures in one season growing some seven inches a day. It consists of a single long trunk or stipe which is attached to the bottom using a mesh of finger-like projections called a holdfast that adheres to rocks. The stipe widens along it’s length ending in a floating, hollow bulb that holds the plant upright in the water column.
From the bulb sprouts two sets of blades or fronds each of which can contain up to 50 individual fronds. The fronds are long (around 12 feet) and narrow (less than 8 inches). The plant seldom is found alone, usually occurring in large dense kelp beds and ranging from Alaska to central California in the nearshore subtidal zone.
The surface of the fronds and stipe are used by a variety of animals and plants as shelter. Kelp crabs can be found along the stipe feeding on various small attached plants as well as the kelp itself. Various species of perch and other fish prowl the understory. It is also eaten by sea urchins (relatives of sea stars) who nibble on the holdfast and stipe like marine beavers.
This group of seaweeds has a complex life history. Bull kelp, unlike other kelp, produce patches on the blades which are composed of mobil reproductive cells called zoospores with half the chromosomes of a regular cell. These patches sink to the immediate area of the parent releasing the zoospores. The zoospores germinate into separate male and female microscopic plants. Sperm then swim from the male plant to the egg of the female plant and fertilizes it. The resulting young plant with a full set of chromosomes grows into the large Bull kelp.
Bull kelp has been used by humans as food. The sliced stipe is made into pickles or salsa and the blades can be dried and eaten like potato chips or added to soups or other dishes.
Sea Brush, Odonthalia floccosa
This red algae is usually found in rocky, low intertidal and shallow subtidal areas with moderate wave action or strong currents. It and several other similar species occur throughout the northeastern Pacific Ocean shoreline from Alaska to central California. They are characterized by a dark red color, brushy appearance and branchlets that are pointed, but are difficult to tell apart. They range in size from a few inches to 20 inches tall. This clump of sea brush is about 12 inches high.
The plant is a perennial, living for over 4 years. Usually the blades die back to basal branches in the fall from which the plant is regenerated in the spring.
Because of its proliferation of branches and branchlets, the sea brush offers shelter for a variety of animals and small plants. Lift the mass of seaweed at low tide and you will usually find several animals, including zooplankton, using the moisture held by the sea brush to survive drying. A study at the University of Washington in 1998 showed that usually diatoms (colonial, single celled plants) attach to the branches in late summer as the plant stops its growth and reproduction. If the bloom occurs earlier it can affect the health and reproductive success of the sea brush.
Thanks to Tom Mumford, seaweed scientist with the Washington Department of Natural Resources, for confirmation of the identity of this species.
Phytoplankton, Dinoflagellates
Plankton, which comes from the Greek word for “drifters”, makes up the bulk of the animals and plants in the ocean. These tiny creatures, only seen with a magnifying glass or microscope, drift with the prevailing currents. Plankton occur everywhere and form the basis of the marine food chain. They are fed upon by small fish and invertebrates (including filter-feeding animals such as clams), who in turn are fed upon by larger predatory animals such as adult fish who then serve as food for sea birds, marine mammals, and humans.
There are two types of plankton, tiny animals called Zooplankton and tiny plants called Phytoplankton. The microscope photograph shows both types of plankton: the sausage shaped creature with large antennae is an animal called a Copepod and the smaller brown circles with lines are plants called Dinoflagellates.
Many Dinoflagellates contain photosynthetic pigments and rely on sunshine for nourishment. However they are animal-like in that they have small flagella that they can use to swim. Some species produce a neurotoxin that effects other marine life as well as humans who eat contaminated shellfish . Blooms of some species can turn the water a reddish color called a “red tide”, but such blooms do not necessarily produce a toxin. To be safe consult your local health department for beach closures (whether a “red tide” is present or not) prior to collecting shellfish for consumption.
Polysiphonia, Polysiphonia sp.
This small red seaweed is about the size of your hand although some species are bigger. The fourteen species can only be differentiated through microscopic examination. They are all finely branched, bright red to dark brown in color and form dense, fluffy mats.
Polysiphonia are distributed from the Aleutian Islands in Alaska to Baja California where they occur in the mid to low intertidal as well as the shallow subtidal zones attached to rocks or other hard objects.
Amphipods and other small crustaceans can sometimes be found hiding among the branches.
Nori, Porphyra sp.
The light brownish red lacy material on top of the green branches of Pickle Weed in the photograph is a common intertidal marine seaweed called Nori by the Japanese. It is also called Laver. There are 22 different species of nori in this area which can only be told apart through detailed examination by experts. Nori is a member of the large group of algae called Rhodophyta or red algae. Red algae are a very diverse group of marine plants found all over the world.
It looks like an unappetizing slippery goo, but in fact it is one of the most commonly eaten seaweeds in the world. Anyone who has eaten the oriental sandwiches called sushi has eaten nori. It is the thin black outer wrapping holding the rice and raw fish together.
Nori used for human consumption is grown in vast aquaculture projects in asia. Nets used to grow the seaweed are seeded from the filamentous life history stage that grows in oyster shells. The nori blade then grows on the nets which is suspended near the surface of the water until it reaches several inches in length. It is then stripped off using an underwater vacuum. The individual blades are meshed together on a sieve making a paper-like product.
The Washington Department of Natural Resources investigated the biological and financial potential of Puget Sound to culture nori in the early 1980’s. After several years of work, in consultation with a nori culture expert from japan, the biological feasibility to culture nori in Puget Sound was established. Small private operations were undertaken but large scale culture has not occurred.
Bleach Weed, Prionitis lyallii
This reddish to yellow-brown seaweed is found in the intertidal and shallow subtidal zones sometimes inhabiting small tide pools at the mid-tide level. It is distinguished from other reddish seaweeds by its tough, elongated and flattened, 6 to 8 inch blades with small leaflets emerging from the sides. In addition it emits an antiseptic smell when crushed, like bleach or iodine, which is thought to be a deterrent to grazing animals.
It can be found from British Columbia to Baja California in Mexico. In more exposed areas the leaves are redder whereas they tend to turn yellowish in quieter waters. This difference is thought to be due to the higher level of nutrients brought to the plant where water movement is high. However, as seen in the photograph, both types of leaves can occur together.
The bleach weed is one of many members of the major group of seaweeds called the red algae with around 600 species in our area. The other seaweeds are the brown algae (around 150 species), many of which are called kelp, and the green algae, such as sea lettuce, with around 130 species. Each group has evolved along a different pathway and therefore are not related.
Pickle Weed, Salicornia virginica
This interesting plant grows in the high intertidal zone in dense mats where it is covered by salt water only once or twice a day. Pickle weed is found in sheltered areas with little strong wave action.
It’s thick, fleshy stems are unique and their high sodium content help the plant tolerate life in an environment high in salt.
The reddish stems are probably a combination of new growth as well as stems from a closely related, annual species with the scientific name of Salicornia europea. The plant will die back in the winter to woody stems.
The young stems are sometimes referred to as ” sea asparagus” and eaten. It is usually cooked by steaming or in a microwave oven then coated with butter.
Up until the late 1700’s, pickle weed was burned to produce a soda ash used in glass making.
Red String Seaweed, Sarcodiotheca gaudichaudii
This stringy red algae is a common summer-time seaweed in the low intertidal and subtidal zones on rocks within sandy-mud habitats. This species ranges from Alaska to Mexico.
Like kelps and other larger seaweeds this species is attached to rocks using a pad of tissue, called a holdfast, which binds the plant to its anchoring rock. Some seaweed holdfasts are disk shaped while others are composed of root-like growths. The main stem of a seaweed is called the stipe. From the stipe arise round branches like those of the red string seaweed and in some species, leaf-like branches called blades.
When fresh the red string seaweed may be used in salads. In the Philippines it is made into a sweet desert. Similar appearing seaweeds in our area are also used as food. Commonly called Red Spaghetti, Gracilaria and Gracilariopsis are used in the production of Agar as well as eaten in Japan and Hawaii.
The red string seaweed has borne several scientific names over the years such as Agardhiella and Neoagardhiella so if you look up this species in a seaweed book be sure to reference all of its names. Two recent publications on Pacific Coast seaweeds are ” Seaweeds of the Pacific Coast” by Jennifer and Jeff Mondragon (2003) and “Pacific Seaweeds” by Louis Druehl (2003). Useful information can also be obtained from an older publication by Bob Waaland (1977) called “Common Seaweeds of the Pacific Coast”.
Wireweed, Sargassum muticum
The common name of many animals and plants can vary between different regions, different people or even between different experts. For example this brown seaweed is called Wireweed in one seaweed identification book, Japanese Weed in another and Sargassum in a third. This is why it is always good to know the scientific name because it will not change based on where you are or who you talk to.
Many of you may have already heard of the scientific name before because another related species occurs in the middle of the Atlantic Ocean in what is called the Sargasso Sea. The name was given by Christopher Columbus’s crew apparently based on the presence of vast amounts of floating seaweed. By the way the Sargasso Sea is not a sea but an area where large scale Atlantic currents bring in drifting material and keep it there forming a unique ecosystem.
This species today can be found both in Japan and from Alaska to Southern California. However it was introduced to the Pacific Northwest in the 1920’s when the first oysters were imported from Japan to expand the local oyster culture program. It occurs in the lower intertidal and upper subtidal zones including tidepools. While normally occurring in sheltered waters it can also be found in wave impacted areas within Puget Sound.
Sargassum is characterized by long thin stems with multiple side branches supported by small, round bladders or floats. Like other introduced species it can often out compete local species and form an extensive floating canopy.
Sea Lettuce, Ulva lactuca
Looking like some sort of green, goopy stuff that washed onto this rock, Sea Lettuce is really a marine plant. It is a very common intertidal plant growing from mean low-tide level to around a plus two feet in our area. It ranges from Alaska to Chile as well as in other parts of the world. The blade can grow up to a foot long during the summer. It dies away as fall approaches leaving a perennial hold-fast from which another blade grows next season.
In other parts of the world the blade is eaten in salads, soups, and other dishes.
Like most plants, Sea Lettuce contains chlorophyll which captures the energy from sun light turning it into food that the cells of the plant can use in a variety of ways. It is only two cells thick so that the green from the chlorophyll shows through.
Sea Lettuce is a member of the class of plants known as Green Algae. Other kinds of algae also occur in the intertidal zone. They are commonly called Red and Brown Algae.
Sea Lettuce does not appear to have any major predators although small marine snails probably eat it when it is small. However one fish does feed on it. A fairly common, shallow water fish called the Buffalo Sculpin eats Sea Lettuce blades in addition to animal prey.
During the summer, parts of Boston Harbor cove can be covered in this species. It can get so thick that masses of it can choke the shallow water area. When it dies the smell of hydrogen sulfide (rotten egg smell) will fill the air.
Eelgrass, Zostera marina
One of several species of seagrass in Puget Sound, eelgrass is the largest with perennial blades that are over 3/16 inch wide and several feet or more long. Normally it occurs in somewhat sheltered intertidal and shallow subtidal areas favoring clear water that allows photosynthesis to depths of a minus 20 feet or so. Eelgrass, like other seagrasses, are flowering plants that have invaded the sea. They sink their roots in muddy sand producing flowers and seeds. Beds also expand through the growth of rhizomes. This species occurs in marine waters throughout the northern hemisphere.
Eel grass occurs in small to large beds where it dramatically changes the ecological setting of the area. The roots stabilize the sediments while the blades not only trap sediment but offer shelter for a wide range of animals and other plants. Animals commonly found in the beds are hydroids, nudibranchs, anemones, jellyfish, starfish and urchins, various crab including Dungenese along with a wide variety of smaller crustaceans, various sculpins, pipefish, tubesnouts and several kinds of perch and juvenile salmon. Eelgrass is also an important spawning substrate for Herring.
An eelgrass bed produces a considerable amount of vegetable matter per year making it very important as a food source for a variety of both large and small animals including the Brandt sea goose and the American Wigeon duck.
Another species of eelgrass that occurs locally is the introduced Dwarf Eelgrass (Zostera japonica) which is much smaller and occurs higher in the intertidal zone in small beds. It is characterized by short, narrow leaves. It was introduced with the first shipments of Japanese oysters.