''Pleurophycus gardneri'' is a species of
brown alga
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate an ...
. It is a deciduous kelp, primarily found in lower, rocky inter-tidal and shallow, rocky sub-tidal locations
and is one of the most abundant kelps found within the Pleurophycus Zone (roughly 30-45m depth).
It is not commonly present deeper in the ocean than 30m and is considered a stipitate kelp.
''P. gardneri'' forms aggregates of densities up to 10m
−2 . These kelp beds reside below giant kelp forests, and were therefore often overlooked by researchers for many years.
This kelp has a range from Central California to British Columbia, Canada, with a lifespan of only 3 – 6 years.
The family of ''P. gardneri'' was previously believed to be Laminariaceae and not Alariaceae, but molecular data supports this particular kelp to be of the family
Alariaceae.
''P. gardneri'' has been referred to as Tender Kelp (1980) or Sea spatula (1985).
Interactions with other species
''Pleurophycus gardneri'' is a habitat to many species of
amphipod, and most commonly supports species specific to stipe burrowing.
Amphipods decrease the lifespan of this kelp due to damages caused by burrowing; any breaks in the plants'
holdfast up to its stipe will kill the plant, hence its heightened mortality rate due to stipe burrowing amphipods. Breaks above the abscission zone of the plants' frond will not kill the plant, but may still decrease fitness.
Reproduction
''Pleurophycus gardneri'' reproduces in the same way as all other
kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms.
Kelp grows in "underwa ...
. It has
diploid sporophytes and a microscopic haploid
gametophyte
A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...
stage.
Mature algal blades have a thick mid-rib which contain sori for reproduction.
A
sorus
A sorus (pl. sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus (plural coenosori) is a compound sorus composed of multiple, fused sori.
Etymology
This New Latin word is from Ancient Gr ...
is able to produce gametes for the kelp.
Perennial characteristics
Mature algal blades have a length of roughly 150 cm.
Annual banding can be found in the stipe of the plant due to its deciduous nature, which researchers often use to identify plant age.
''P. gardneri'' loses all foliage by late fall and then soon thereafter (after a roughly two-week dormancy) begins to grow new blades.
For new blades to begin growing, light must be present.
Premature blade deterioration and breakages were seen as a direct result of warmed ocean temperatures. It is believed that temperatures around 14-15 C trigger blade deterioration. Following an
El Niño
El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...
, this kelp was recorded to have prematurely dropped blades.
References
{{Taxonbar, from=Q29347903
Alariaceae