| |
Sea
lettuce
Ulva sp.
Family Ulvaceae |
|
|
Sea lettuce is seasonally
abundant and at times can
carpet the shores of Chek Jawa
|
Sea lettuce looks like its namesake land plant. It is a lovely shade
of light green and each plant usually has a single, broad and thin
blade. The blade is actually only two cells thick! This allows sea
lettuce to grow rapidly in nutrient-rich water as it has a high surface
to volume ratio. Sometimes, sea lettuce can carpet Chek Jawa’s shores
in a layer ankle-deep.
Green carpet welcome: Be careful!
The 'green carpet' of seaweeds can be slippery and conceal rocks and
other things that might trip you up. Also, many animals hide under
this 'green carpet', so don't step everywhere. Just keep to the parts
that are already stepped on to minimise the impact of your visit.
Sea lettuce parts: Compared to
most other seaweeds, Sea lettuce species can better tolerate being
exposed during low tide. So it grows near the shore. The blade is
attached with a small holdfast, but the seaweed is also often seen
floating unattached, possibly dislodged.
Smell of the sea: When the shores
are covered with Sea lettuce, you can smell the distinctive aroma
of seaweed gently toasting in the sun. This is truly the smell of
the sea!
Sea lettuce babies: Sometimes,
you might come across a sea lettuce blade that is white or transparent.
This could be because the sea lettuce has become fertile and converted
some of its cells into reproductive cells and released these cells.
Often, this happens along the edge of the blade.
Role in the habitat: Sea lettuce
is one of the seaweeds eaten by the Green turtle (Chelonia mydas),
as well as other creatures. The dense tangle of seaweed also provides
plenty of hiding places for the small animals that live in the seagrass
lagoon.
Human uses: Sea lettuce is fed
to pigs and livestock. In the past, they were collected in boatloads
in the Straits of Johor, washed in freshwater then cooked and fed
to pigs. Sea lettuce is cultivated for animal feed in some places.
In some places, it is also eaten by humans, as a salad or mixed with
other vegetables. It is also reported to have antibacterial properties,
and to be used to treat goiter, gout, scrofula, burns and other irritants.
Sea lettuce also makes good packing material to cover more valuable
Caulerpa seaweeds during shipping and transport, or to cover
fish for sale. As Sea lettuce grows well in polluted waters, it is
also used as an indicator of water quality. |
|
Ulva lactuca
has few or no holes
in its blade
Ulva reticulata
Has lots of large holes and looks like
shredded cellophane
Hiding among
the lettuce! |
|
quick
facts
10-15cm wide, common in the seagrass lagoon and along the
shore |
