THE STEINHART AQUARIUM - Gulf of Guinea Science ...

ALGAE
GREEN (DIVISION CHLOROPHYTA)
Sea Lettuce
Ulva spp. (Ulvaceae)
Distribution: Ulva taeniata: Oregon to Point
Dume, California. Other Ulva spp. more widespread.
Habitat: Intertidal and shallow subtidal.
Appearance: Thin thallus, colored leafy
green.
Reproduction and Development: Undergoes
a cyclic alternation of generations between the
sporophyte (spore-producing alga) and gametophyte
(gamete-producing alga). Both types
appear identical macroscopically. Mobile flagellated
zoospores are produced by meiosis. The
zoospores disperse and attach to a hard substrate,
where they grow into a haploid male or female
(the gametophyte), which produces and releases
sperm or eggs by mitosis. Fertilization produces
the diploid zygote, which settles, attaches and
grows to become a diploid sporophyte.
Conservation status: Tolerant of organic and
metal pollution (although there are limits). Most
likely will increase in population numbers as
their more sensitive tide pool mates die off. Grow
rapidly and produce vast quantities of spores
and gametes, thus a true sea “weed.”
Remarks: A popular “sea vegetable” for
human consumption.
Ron DeCloux
California Academy of Sciences
A FIELD GUIDE TO SPECIES OF
THE STEINHART AQUARIUM
19
Moss Ball
Aegagropila linnaeim (Cladophoraceae)
Filamentous Green Algae
Distribution: The free-floating spherical
forms are known only from Austria, Iceland,
Scotland, Japan, and Estonia.
Habitat: Lake balls, as they are sometimes
called, are restricted to a few freshwater lakes.
Appearance: Velvet-green rounded shape.
Known to grow to 30 cm (i.e., larger than the
tank it presently inhabits).
D i e t : P r o d u c e s n u t r i t i o n t h r o u g h
photosynthesis.
Reproduction and Development: Size of balls
increases from vegetative growth.
Conservation Status: A number of the lakes
where these enigmatic balls once formed no
longer support their growth, perhaps due to
eutrophication and in some cases the use of
the lakes for timber transportation, a practice
that blocked sunlight to the plants. The plant’s
limited dispersal capabilities may also increase
the effect of local habitat degradation.
Remarks: The moss ball is a species of
filamentous green macroalgae (Chlorophyta).
A moss ball is a rare growth form.
The moss ball is called “Marimo” in Japan. A
mari is a soft bouncy play ball; “Mo” refers to