 |
| Teluk Pelanduk, Port Dickson |
Seagrass
Seagrass are actually not ‘grasses’ at
all, as they do flower. Like land plants, seagrass produce oxygen. The depth at
which seagrass are found is limited by water clarity, which determines the
amount of light reaching the plant. Light is required for the plants to make
food through photosynthesis.
Teluk Pelanduk ecosystem growth some
species of seagrass which can be seen in lower tide only because of low water
turbidity.
Samples of
seagrass that we found during the trip.
1. Halodule pinifolia
Halodule also known as needle be short to
very long. The leaves have three parallel veins which can be quite distinct. In
most, the central mid-rib vein is quite prominent. The leaves emerge from thin
rhizomes (underground stems) which have fine rootsseagrass is a dominant
species in Teluk Pelanduk. Their habitat usually on the edges of the sand bars
towards the low water mark.
2. Enhalus acoroides
Enhalus acoroides
has the longest leaves of seagrasses found on our shores. The strap-like
leaves are 1-2cm wide and 30cm-1.5m long. The edges of the leaves are slightly
rolled. The leaves have air channels in them.
This seagrass has thick rhizomes (underground stems)
that are densely covered with the stiff black fibrous strands, which are the
remains of old leaves. The rhizomes have also many cord-like, hairless roots.
The roots also have wide air-channels.
3. Thallasia
hemprichii
The seagrass has strap or curved, sickle-shaped leaves
(0.5-1cm wide and 7-40cm long, usually less than 25cm). The tips are usually
rounded and smooth. The leaves may appear speckled due to tannin cells that
appear red, purple or dark brown. It has thick rhizomes (underground stems)
about 2-4mm in diameter which are white or pink. The rhizomes have air channels
and usually have obvious node scars that are triangular with persistent leaf
sheaths. Shoots emerge from these rhizomes, each shoot with 2-6 leaves encased
in sheaths about 3-8cm long.
4. Halophila
ovalis
The seagrass has oval, spoon-shaped leaves
and is sometimes also called 'paddleweed' or fan seagrass. It comes in a wide
range of sizes (0.5-1.5cm wide and 0.5-2.5cm long) and shapes from oval, to
nearly oblong or spoon-shaped. The leaf edge is smooth with no serrations,
there is a vein just within the leaf margin (intramarginal vein). The leaf has
obvious cross veins (4-25) and is held on a long thin stalk. It has thin,
smooth, white rhizomes (underground stems) about 2mm in diameter. The leaves
emerge in pairs from these rhizomes. The emerging shoot is encased in a pair of
transparent scales.
"Seaweed" is the
common name for countless species of marine plants and algae that
grow in the ocean as well as in rivers, lakes, and other water bodies.
Some seaweeds are microscopic, such as
the phytoplankton that live suspended in the water column and provide the base
for most marine food chains. Some are enormous, like the giant kelp that grow
in abundant “forests” and tower like underwater redwoods from their roots at
the bottom of the sea. Most are medium-sized, come in colors of red, green,
brown, and black, and randomly wash up on beaches and shorelines just about
everywhere.
The vernacular “seaweed” is a bona-fide
misnomer, because a weed is a plant that spreads so profusely it can harm the
habitat where it takes hold. (Consider kudzu, the infamous “mile-a-minute vine”
that chokes waterways throughout the U.S. Southeast). Not only are the fixed
and free-floating “weeds” of the sea utterly essential to innumerable marine
creatures, both as food and as habitat, they also provide many benefits to
land-dwellers, notably those of the human variety.
Samples of
seaweed that we found during the trip.
1. Glacilaria sp.
Gracilaria is a genus of red algae (Rhodophyta) notable for its economic importance as an agarophyte, as well as its use as a food for humans and various species
of shellfish.
