Zostera marina - Common eel-grass

Family: Zosteraceae ^[E-flora]

Introduction
"Common eelgrass is a perennial (sometimes annual) aquatic rhizomatous species native to the coastlines of North America and Eurasia, where it is found in cooler waters of the North Atlantic and North Pacific; in warmer parts of its range it dies back in the summer (Wikipedia 2012). It is a species of calmer waters in the sublittoral zone (Wikipedia 2012).
Common eelgrass co-occurs with Japanese eelgrass (Zostera japonica) from BC south to Oregon, however Japanese eelgrass is found primarily in upper intertidal zones (Green and Short 2003).
Common eelgrass is a significant species in coastal waters: "Zostera marina is the dominant species in terms of biomass and habitats on the Pacific coast of North America where it grows in: the shallow waters of the continental shelf, the Gulf of California, coastal lagoons such as San Quintin, Baja California, Mexico and Izembek Lagoon, Alaska, estuaries formed by tectonic processes like San Francisco Bay, and coastal fiords similar to Puget Sound, Washington. It is found along the coast of British Columbia, including the coasts of Vancouver Island and Queen Charlotte Islands (Haida Gwaii) in sheltered bays and coves including Bamfield Harbour and Sooke River. " (Green and Short 2003)." ^[E-flora]

Identification

"Zostera marina is a PERENNIAL growing to 1 m (3ft 3in). It is in flower from Jun to September, and the seeds ripen from Aug to October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Water.
Suitable for: light (sandy) and medium (loamy) soils. Suitable pH: acid, neutral and basic (alkaline) soils and can grow in saline soils.
It cannot grow in the shade. It can grow in water." ^[PFAF]

Origin Status: Native ^[E-flora]
"General: Perennial, aquatic herb from slender rhizomes; stems annual, branching, 100-250 cm long, arising from the rhizome nodes." ^{[IFBC-E-flora]}
"Notes: Recognition of infraspecific taxa in Z. marina (Brayshaw 1985), based on leaf features, appears to be a meaningless exercise considering the plasticity of these features and the lack of research." ^{[IFBC-E-flora]}

Habitat / Range
"Sheltered subtidal flats and common along the coast; cosmopolitan, N to AK, S to CA; E North America, Greenland, Europe, E Asia, N Africa." ^{[IFBC-E-flora]}
"Fine gravel, sand or mud in the sea from low water spring tides down to depths of 4 metres[17]. It is rarely found in estuaries[17]." ^[PFAF] "Europe, including Britain, from Norway south and east to the Mediterranean." ^[PFAF]

Edible Uses

"The Saanich and Cowichan cooked the fleshy roots and leaf bases of this plant in steaming pits to flavour seal, porpoise, and deer meat (Harry, 1969)."^{[EthnoCoastSalish]}

• Fish Stuffing: "To prepare fish. Various marine plants, mainly algae, have been used for this purpose in Norway. Gunnerus noted such use of Zostera in southernmost Norway: "Fish is salted in it, as I saw myself on a visit to Fladstrand in 1737. But it makes them [turn] black, and it will only be eaten by the poor" (13:2-3; translated from Latin)." ^[OUZM]
• Leaves: "Leaves - raw or cooked[177, 256]." ^[PFAF]
  
• Leaf Bases "The leaf bases are crisp and sweet, they were often used as a feast food by the native North American Indians[256]." ^[PFAF] The Saanich and Cowichan cooked the fleshy roots and leaf bases of this plant in steaming pits to flavour seal, porpoise, and deer meat (Harry, 1969).^{[Turner&Bell1]} "The uncooked fleshy roots and leaf bases of eelgrass were a favourite food (King, 1972)." ^{[Turner&Bell2]}
• Seed: "Seed[177]. No more details are given." ^[PFAF] "Seri Indians of Mexico ground the seeds into an edible flour. The grain, although small and relatively bland, is toasted, winnowed, and ground into flour and made into a gruel, traditionally combined with other food (e.g., sea turtle oil or honey) in Baja California.)^"[MPB-Duke]
  
• Root: "The root of the plant is chewed for its saccharine juice[2, 105]. The root is crisp and sweet, it was used as a flavouring by the native North American Indians and was also dried for winter food[256]. The raw rhizomes were often used as a feast food[256]." ^[PFAF] "For this last, they selected the youngest rhizome segments with all but the tender central leaf removed; this leaf was wrapped around the rhizome. People usually harvested cacayem at low tide from the canoe, using a long twisting pole." ^{[CultPacSilverweed]}
  • Harvesting: "The plants were gathered by canoe using long hemlock poles. These poles were put into the water, twisted until the long leaves were wrapped around them, and then pulled up with the plants attached. The leaves were broken off, and the fleshy stems and roots washed and carried home. Usually the entire tribe was invited to come and eat the eelgrass. Pieces were spread out on mats, each person took four pieces, plucked off the small roots, and peeled off the leaves. He then put them together, broke them to the same length, and tied them in a bundle with the leaves. The bundle was dipped in oil and eaten with the fingers. No one was permitted to drink water afterwards." ^{[Turner&Bell2]} "The Hesquiat (Nuu-chah-nulth) of Vancouver Island were said to prefer the type with light green rhizomes, rather than dark rhizomes. They pulled them up around May, washed, and ate them in large quantities (Turner and Efrat, 1982)." ^{[Turner&Kuhnlein]}

Other Uses

• Stuffing: "The dried leaves and stems are used as a packing material[46, 61, 66, 100]." ^[PFAF] "Zostera was "very frequently used, here as in other countries, as stuffing for mattresses" (11:354, translated from Norwegian). Information on such use has been collected from numerous informants, mainly along the western coast of Norway (10). Zostera has also been used as furniture stuffing (12:112)." ^[OUZM]
  
• Insulation: "Commercial gathering was modified from for- mer non-commercial practices. Early settlers collected leaves from beach wrack and used them wet as green manure and dried for animal bedding and "banking up" around houses and out buildings (Ricker 1941). The custom of "banking up" also occurred in New England and is achieved by layering outside walls with loose, dry leaves of Z. marina (Wilkes 1950:2). This protection buffered humans and their live- stock against winter cold and prevented cellars and icehouses from warming in summer (Cottam 1934:192)." ^{[WYLLIE-ECHEVERRI&COX]} "Cabot's Quilt" was made by stitching various thicknesses of dry Z. marina, leaves between layers of heavy Kraft paper [paper or paperboard (cardboard) produced from chemical pulp produced in the kraft process." ^[Wiki-KP] "Initially three varieties were made: (1) Single-ply -- common lining for houses; 1/3" (0.8 cm) thick; (2) Double-ply -- sound deadening material; 1/2"(1.27 cm) thick and (3) Asbestos-single and double ply covered with asbestos rather than Kraft paper. Over time other grades were introduced bringing the total to eight varieties of "Cabot's Quilt" available to the construction trades. The product was used extensively in houses, office buildings, hotels, apartment buildings, warehouses, schools, hospitals, conservatories and lecture halls throughout Canada, the U.S. and Great Britain." ^{[WYLLIE-ECHEVERRI&COX]}
  • "Independent studies found the "Quilt" to be an efficient thermal and acoustical barrier, particularly for sensitive environments such as lecture halls and music conservatories. ...by 1953 (Cottam and Munro 1954) but Guildfords Limited, rather than SCI, bought the leaves and processed them in Sable River, north of Yarmouth to become "Seafelt." Production of "Seafelt" was discontinued with the advancement of fiberglass insulation and other synthetic fiber products in the early 1960s (J. Guildford pers. comm.)." ^{[WYLLIE-ECHEVERRI&COX]}
  • Harvesting: "...leaf litter was gathered from the water and the rocky intertidal region. Wet leaves were then spread atop the recently mowed hay fields to dry. The work began in late July after the hay was cut from the fields and, in some years, continued until October. Leaves were turned until they were thoroughly dry, then loaded into horse drawn wagons..." ^{[WYLLIE-ECHEVERRI&COX]}
    
• Manure: "The plant is frequently used as a manure[2]." ^[PFAF] "Such use is first mentioned by Hans Strom in 1762, from the Sunnmore area at the W coast: "The only thing marhalmen is used for in our area is as manure for the fields" (5: 188, translated from Norwegian). Some further details are found in the diary of Pehr Kalm (6). On the way to North America, his ship was forced to stay at the coast of southernmost Norway for over a month; an excerpt of his observations here was published in 1748 (7). On 20 December 1747, he noted that Zostera "was here drifted ashore in large quantities; it was considered the best of all sea-weeds to place in stacks, and left to rot, later to be used as manure in the fields, for which is should be particularly well suited on sandy soils." (cited from 6:58, translated from Swedish)." ^[OUZM] "At Karmoy in Rogaland, Zostera was mixed with dung and used as manure (8:291, 9:8). Curiously, people at Sem in Vestfold, SE Norway claimed it could not be used for this purpose, because it promoted weeds, in particular Elymus repens (10:682)—but so, of course, would any kind of manure." ^[OUZM]
  
• Roofing: "In the past, Zostera was frequently used as roof covering in the coastal districts of Denmark. Such roofs were considered water¬proof and warm, and would not easily burn." ^[OUZM]
  
• Fibres "...fibres in sea-grass samples collected on Baltic coast beaches possess interesting mechanical properties. The structure of these fibres differs from that of flax fibres. ... The mechanical properties of these fibres are very promising. In their natural state tensile modulus values up to 28 GPa and strengths up to 770 MPa were measured. These values are comparable to those of other terrestrial fibres (sisal and jute) currently being considered for polymer reinforcement in environmentally friendly composites." ^[SPF]
• Misc: "Brownish “roots” (actually rhizomes) eaten by black brants, Canada geese, mallard ducks, and cattle (DEM)." ^[MPB-Duke] "This seaweed [Porphyra] was also used, along with eelgrass (Zostera marina), to generate steam in the board-bending process of box-making (Boas, 1921)."^[BCEthno]

Medicinal Uses

• Misc: "Diarrhea Eb28: 429 The plant is used by the Seri Indians of Mexico for diarrhea." ^[MPB-Duke]
• Leaves: "The leaves are used in the treatment of dropsy, goitre and women's illnesses[218]." ^[PFAF]

Misc Uses
Zostera has been used as cover for cultivated plants, e.g., potatoes, and as lining in ditches to conserve ice during the summer. Other Danish uses mentioned by Brondegaard include strewing material to protect against sand-drift, as manure (though Zostera was not considered well suited for this purpose), and as cattle fodder. It was also burned to extract salt from the ashes. A curious, late World War II use was as filling in bicycle tubes." ^[OUZM]
Large quantities of Zostera have also been collected in Germany and the Netherlands (22: 206), partly by scything (23:192); a major use was in furniture, as a cheap substitute for horse hair." ^[OUZM]
An old use of Zostera worth mentioning was as packaging material for the famous glass-ware from the factories of Venice; it was thus called Alga vitriariorum." ^[OUZM]

Phytochemicals

"Zosterin (a seagrass pectin) has antibacterial and immunomodulatory activities of therapeutic effcacy in experimental infections (X1755708)."^[MPB-Duke]

Essential Oil
"The seagrass were collected along the coast of an inland sea (Aio, Yamaguchi, southern Japan). Fresh shoots were subjected to simultaneous distillation extraction (SDE) to give an essential oil with a characteristic odour. The volatile compounds in the oil were identified by comparison of Kovats indices and GC-mass spectral data with those of authentic compounds (Table 1)." ^[VOZM]

"The oil yield (0.7%) from the seagrass was higher than that from the mar- ine green alga, Ulva pertusa (~0.007%) [2, 6, 7]. The composition of volatile components of the seagrass oil are essentially similar to that of the algal oil. However, with the seagrass oil, nitrogen compounds, such as 1- pyrroline, 4-methylpyridine and nicotine were de- tected as characteristic components. (7Z, 10Z, 13Z)- Hexadecatrienal, (6Z,9Z, 12Z)-pentadecatrienal, n- pentadecanal, n-tetradecanal, (2E)-nonenal and (2E)- octenal, which were identified in the Ulva oil were not detected in the seagrass oil." ^[VOZM]

Fatty Acids
"Thus, the eelgrass species investigated differed with respect to their fatty acid com- positions: For Zostera nana the main fatty acids were identified as the 16:0, 16:1, 18:1, 18:3, and 18:4 varieties, and for Zostera marina 16:0, 18:1, 18:2, 18:3, and 20:5. The main phospholipids were phosphatidylcholine and phosphatidylethanolamine, their amounts in the two species being approximately the same." ^[LEZ]

• Allelochemicals - Water soluble allelochemicals of green and dead leaves of Zostera marina inhibited growth of algae and bacteria (Harrison and Chan 1980). ^{[Cheema Alleleopathy]}
• High lithium levels ( 66 -- 100 mg per kilogram raw weight) have been observed in Z. marina ^{[Shkolnik TEP]}

Cultivation

• Groundcover: "As ground cover for sheep....boat-loads of Zostera were collected, dried on the ground, and used together with kelp to provide a dry and pleasant cover for sheep to rest on (8:291, 9:8)." ^[OUZM]
• Fodder: "In Norway, "It was said by several, among them Christian Mansson, that when it [Zostera] is drifted ashore along the west coast of Norway, the cows there will eat it as eagerly as grass, as long as it is green and fresh. At the same western side of Norway, the inhabitants will take a boat and row out where it grows, put the oar down in the water among it, and then turn the oar around, upon which the sea-weed will fasten to it, whence they pull it up, and put it in the boat. When they, using this methods, have collected as much as they need, they row it home, and give it to the cows, which, when they have got used to it, will eat it as eagerly as grass, when it is green, and thrive. Later, I talked to several other old men, who had been to western Norway (. . .), and all confirmed the same, viz. that this sea-weed is the sole winter fodder of the cows, which they will eat as eagerly as grass (. ..)" " ^[OUZM] "... north of Trund-hiem people at the coast collect sea-weed spread it on stones to dry, and the n store it in stacks. In the winter, they mix this sea-weed with grass or straw, and feed it to the livestock, which are said to eat it eagerly. He told me that at his birth¬place at Trundhiem he had often observed that during the summer, cows would wade out to sea until the water was at their neck, just to get hold of this sea-weed" " ^[OUZM] "Zostera was used to feed livestock: "(. ..) fresh or cooked, it is eaten by horses, cattle, sheep and goats. Some people at Hitra, Fosen, when their animals are severly starving, and they have brought them other species in vain, save them from death by its help" (13:2; translated from Latin). Locally, it was still used in the 20th century. At GimsOy people would scythe Zostera while submerged, so that it floated and could be collected; it was considered a good fodder for cattle and sheep (10)." ^[OUZM]
• Nitrogen & Phosphorus uptake: "High nutrient uptake capabilities of leaves have also been reported for the submerged macrophytes Ruppia maritima and Zostera marina, where weight-specific uptake rates of PO43− and NH4+ by leaves are noted." ^{[Dhir PRAPECU]}

"A plant of shallow sea water, it is not really suitable for normal cultivation. Fast growth, as observed for the eelgrass Zostera marina, is a counteracting strategy to avoid light limitation. The leaves of Z. marina grow up to 6 cm per day and remain uncovered for nearly one week which enables maximum photosynthetic activity (Wium-Andersen and Borum, 1980)." ^{[Reigosa Alleleopathy]}

Habitat: "At the Skokomish River delta in Puget Sound, WA, USA, the combined effects of logging and water withdrawal led to the loss of 15–19% of highly productive low intertidal surface area and a 17% loss of eelgrass (Zostera marina) habitat. This was because of a loss of sediment transport capacity in the lower river and estuary due to water diversion and increased sediment deposition from forest harvesting (Jay & Simenstad 1996)." ^{[Northcote FF]}

Pathogens: "Labyrinthula spp. were implicated as pathogens in a wasting epidemic of eelgrass (Zostera marina) at the west coast of North America in the 1930s (Young, 1943; Muehlstein et al., 1991), causing considerable disturbance to the littoral ecosystem and collateral damage to the local fisheries industry. However, although Labyrinthula spp. are still frequently associated with pieces of moribund Zostera shoots, no further epidemics seem to have occurred since."^{[IntrotoFun3]}

Propagation "Seed - best sown as soon as it is ripe. Division." ^[PFAF]

Synonyms

• Zostera marina var. latifolia Morong , var. stenophylla Asch. & Graebn. ^[E-flora]
• Zostera oregano ^[E-flora]
• Zostera pacifica L. ^[E-flora]
• Zostera stenophylla ^[E-flora]

References

1. [BCEthno]The Ethnobotany of the Southern Kwakiutl Indians of British Columbia, NANCY CHAPMAN TURNER AND MARCUS A. M. BELL
2. [CultPacSilverweed]Cultivating the tekkillak, the ethnoecology of Aeksem, Pacific silverweed or cinquefoil, T. Abe Lloyd, Thesis, Northland College 2002
3. [DukePhyto] http://www.ars-grin.gov ,Accessed Feb 8, 2015
4. [E-flora] http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Zostera%20marina&redblue=Both&lifeform=7, Accessed Dec 16, 2014
5. [EthnoCoastSalish]The Ethnobotany of the Coast Salish Indians of Vancouver Island, NANCY CHAPMAN TURNER AND MARCUS A. M. BELL
6. [LEZ] Lipids of the eelgrasses Zostera nana and Zostera marina, Dembitskii, V. M., Chemistry of natural compounds, V.25 Issue 5, 1989
7. [OUZM] On the uses ofZ ostera marina, Mainly in Norway., Torbjørn Aim, Economic Botany, Winter 2003, Volume 57, Issue 4, pp 640-645
8. [PFAF] http://www.pfaf.org/user/Plant.aspx?LatinName=Zostera+marina, Accessed Dec 16, 2014, Nov 8, 2020
9. [SPF] Structure and properties of fibres from sea-grass (Zostera marina), P. Davies , C. Morvan, O. Sire and C. Baley, Journal of Materials Science, 2006
10. [VOZM] Volatiles from Zostera marina, Wataru Kawasaki, Kenji Matsui, Yoshihiko Akakabe, Noriyasu Itai, Tadahiko Kajiwara, Phytochemistry, Volume 47, Issue 1, January 1998, Pages 27–29
11. [WYLLIE-ECHEVERRI&COX]THE SEAGRASS (ZOSTERA MARINA [ZOSTERACEAE]) INDUSTRY OF NOVA SCOTIA (1907-1960),SANDY WYLLIE-ECHEVERRIAA ND PAUL ALAN COX, Economic Botany 53(4) pp. 419--426. 1999
12. [Wiki-KP]http://en.wikipedia.org/wiki/Kraft_paper, Accessed Jan 23, 2015

ZOSTERA EEL-GRASS

"Stem: < 3 m. Leaf: 0.5–1.5(2) m, (0.5)1–18.5 mm wide. Inflorescence: enclosed by subtending, membranous, sheath-like leaf base; staminate, pistillate flowers alternate. Pistillate flower: ovary tapered to short style.
12 species: marine waters worldwide. (Greek: from ribbon-like leaves) [Coyer et al. 2008 Ann Bot 101:73–87; Dean et al. 2008 Madroño 55:93–112] Important food source for marine animals, some aboriginal humans; Zostera asiatica Miki reported for California (Coyer et al., Dean et al.), possibly naturalized, but may not be distinct from Zostera marina." ^[Jepson]

Local Species;

1. Zostera japonica - Japanese eel-grass ^[E-flora]
2. Zostera marina - common eel-grass ^[E-flora]

References

• [Jepson] 2013. Zostera, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=9712, accessed on Jan 24 2015

Zostera japonica - Japanese eel-grass

"General: Perennial, aquatic herb from slender rhizomes; stems annual, branching, 100-300 cm long, arising from the rhizome nodes." ^{[IFBC-E-flora]}

"Habitat / Range Tidal mudfats; rare in SW BC, known only from Boundary Bay and Tsawwassen; introduced from E Asia." ^{[IFBC-E-flora]}

Synonyms: Zostera americana (Den Hartog) ^[E-flora]

References

• [E-flora] https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Zostera%20japonica&redblue=Both&lifeform=7, Accessed November 8, 2020
• [Jepson] 2013. Zostera, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=9712, accessed on Jan 24 2015