Seagrasses
About Seagrasses
A healthy seagrass bed of dense, green growth, crawling with animals
and fish swimming above is a wonderful sight. On a warm, sunny day in
clear water you can actually see the bubbles of oxygen rising up out
of the seagrass leaves. Seagrasses provide gases and nutrients that
are essential part of marine food webs.They hold sediments together
and provide habitats for adult and young fish and other animals. There
are about eight different kinds of seagrass that grow in Victorian coastal
lagoons, estuaries and open coasts.
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Seagrass
Health
It is natural for some algae, sponge or other encrusting life form to
grow on seagrass blades. When there is only a small amount of this growth
(called epiphytes - pronounced epi-fights) this is not a problem, however
too much can smother and kill seagrass. Harmful algal growth is often
caused by a high level of nutrients in the water - often coming from
farms, households, drains and human and animal excrement.
Also, if the surrounding water becomes murky and blocks available sunlight
then seagrasses can weaken and die. This murkiness is often caused by
dirt and sand floating in the water and again is often caused by actions
happening on land - like building roads and chopping down trees, or
by coastal dredging.
Chemical pollution from land and marine sources also harms seagrass.
In Western Port there was an 85% decline in the total seagrass cover
between 1974 and 1984. A combination of human activities is believed
to be responsible for the loss. Generally seagrass takes a long time
to grow back after it has been damaged which is also why is it so important
to protect and restore existing areas.
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Some
Seagrass Facts
- Seagrasses share many characteristics
with their land ancestors. They have leaves, veins and roots
and reproduce by flowers and seeds.
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