Habitat & Distribution
Pickleweed is a common coastal species found on beaches, tidal flats and salt marshes that are not highly exposed to waves. Distribution in our region is from Alaska to Mexico.
Sarcocornia pacifica. Photo credit: Wikimedia Commons
Shore Plants and Seagrasses | 45
Identifying Pacific Seaweeds
Seagrasses
Seagrasses are flowering plants that have adapted to the marine environment. These plants form ecologically and energetically important meadows in the lower intertidal and upper subtidal regions. Studies by Paul G. Harrison (University of British Columbia), Peter McRoy (University of Alaska) and Ron Phillips (Seattle University) have defined the importance of these plants to animal populations inhabiting and visiting these meadows. For example, seagrasses have a level of productivity approaching that of an intensely managed Puerto Rico alfalfa field (see Seaweed Productivity, p. 253).
Zostera (eelgrass) p. 46
Phyllospadix (surfgrass) p. 47
Surfgrass bed at low tide in Pacific Grove, CA.
Pacific Seaweeds
46 | Seagrasses
Zostera Eelgrass
Class Monocots Order Alismatales Family Zosteraceae
Number of Species
Of the 15 species of Zostera (Greek=aquatic plant), two reside in our area: Z. mar-ina and Z. japonica. Zostera marina is common; Z. japonica is uncommon and was accidentally introduced from Japan, pos-sibly as packing for Japanese oyster spat (see Sargassum, p. 195).
Description
Zostera is a true flowering and seed-producing plant. Our native species, Z. marina, has dull green leaves usually wider than 4 mm (0.16 in), flattened in cross-section and up to 3 m (10 ft) long.
Surfgrass (Phyllospadix), by comparison, generally has nar-rower blades and grows on semi-exposed to exposed rock in the low intertidal zone.
Zostera marina and other seagrasses have considerable potential for habitat conservation. Unlike seaweeds, seagrasses are adapted to living on soft marine bottoms, so they may be planted on unstable or disturbed soft bottoms, where they can curb erosion by holding down and trapping sediment. This is not to say
Zostera marina.
Zostera marina.
Shore Plants and Seagrasses | 47
Identifying Pacific Seaweeds
that seagrass beds themselves are immune to erosion. Changes in local current patterns or scarring of the beds by vehicles, etc., may destabilize the sediments, bringing about destruction of the grasses and all that depend upon them.
The leaves of Zostera were used as mattress stuffing and house insula-tion in the early 20th century. The loss of eelgrass beds in the North Atlantic Ocean, which was associated with the population explosion of a marine slime mould, brought about the collapse of the Nova Scotia eelgrass mattress stuff-ing industry and severely reduced populations of associated marine animals. Subsequently, synthetic materials have replaced eelgrasses in industrial uses.
Habitat & Distribution
Zostera plants are usually in wave-protected areas, rooted in mud or muddy sand from Alaska to Mexico.
Phyllospadix Surfgrass
Class Monocots Order Alismatales Family Cymodoceaceae
Number of Species
Of the five species of Phyllospadix (Greek=leaf and spike of flowers) world-wide, P. scouleri, P. serrulatus and P. torreyi are found locally.
Phyllospadix scouleri at low tide.
Pacific Seaweeds
48 | Seagrasses
Description
Phyllospadix has bright green blades usually less than 4 mm (0.16 in) wide. Phyllospadix scouleri and P. serrulatus have blades 2–4 mm (0.08–0.16 in) wide and usually less than 1 m (3 ft) long. They may be distinguished from each other by the presence of transparent teeth along the margin of young P. serrulatus leaves, which can be seen with a magnifying glass. The third species, P. torreyi, has blades 2 mm (0.08 in) wide or narrower, and up to 3 m (10 ft) long.
As flowering plants have adapted their reproduction to the marine environment, some curious morphological features have evolved. Seagrass pollen may occur in a variety of strange shapes: thread-like, spherical, boomerang-shaped. Joe Ackerman (University of Guelph) has studied pollination in sea-grasses having filamentous (thread-like) pollen.
This pollen tumbles through the water, sweeping large areas, thus enhancing its chance of encountering the stigma (the pollen-receptive part