In the words of Arnie “I’ll be back” and here I am.
So jumping straight into it. I want to talk about and
ecosystem that you've probably all heard of but many of you know very little about
or simply underestimate its importance in the marine environment. I’m going to
talk about seagrass meadows this is a subject which I only know limited amounts
about but hopefully I’ll be able to learn through writing this post along with
you guys out there reading it.
Seagrass is found throughout the oceans and is not solely
constricted to the tropics and warm waters around the equator. They are currently
50 known species of seagrass across the world and like I said they can be found
in the waters around Alaska all the way down to water surrounding New Zealand.
They evolved from land plants which slowly moved into the intertidal range
before becoming completely aquatic; due to their specific requirements
seagrasses are usually tide to areas of shallow water where they receive
sufficient amounts of light, oxygen and nutrients. However in areas which
predominantly have good visibility under the water some species can grow at
depths of up to 20-30m.
Now in the opening paragraph I said that seagrass was an
extremely important ecosystem. On average 40 times more animals occur within
seagrass meadows compared to areas of clear sand in the same locations. It is also
home to many specific niche organisms which rely solely on seagrass as a source
of food and shelter such as some pipefish (eg Robust Ghost Pipefish), seahorses
and of course larger animals such as green turtles and most well know Dugongs,
with seagrass being the only source of food for Dugongs. They consume so much in fact that their feeding
trails through seagrass can be visible in satellite images of some meadows.
Along with providing food they also provide structure to the
sea bed as they have extensive root systems which grow in the search for the few
available nutrients. These roots help to stabilize the sea bed as well as
maintaining water qualities. They are also critical in nutrient dynamics as
primary produces they unlock the nutrient held within the sand and make it
available for other marine life.
Seagrass meadows are usually found in sheltered sections of
water for example within the tropics this is usually the area between mangroves
and coral reefs, while in more temperate climates a sheltered cove or behind a
headland are common locations.
Seagrass also help in reducing the effect humans have on the
worlds; an area the size of a football field will process 780 sewage wastes
each year. Along with absorbing 7,500mile worth of vehicle pollutants and
generate an estimated $35,000 a year in ecological services. Unfortunately the
net loss of seagrass since 1980 equates to one football field of seagrass every
30 minutes.
The decline of seagrass is down to a number of different
attributing factors, for instance the rise in sea temperature is have a significant
effect of it’s distribution however this is not the only cause of its decline.
Human activities such as boat propellers rip up large amounts of grass
including it’s roots. Also mooring sites undergo a process known as scouring
where the chain attached to the buoy hits the bottom when the tide drop and
produces circles of sand around each site where seagrass used to grow.
Excessive waste and pollutants also kill or bury seagrass meadows and as over a
billion people live within 50km of seagrass meadows this is a problem which is
only set to increase.
There are several thing which can be done to help seagrasses
for instance there are several charities such as project seagrass, you can also
getting involved and volunteer in some of these project and help monitor
seagrass decline and its effects.
Finally I’m going to leave you with some information on work
which is being conducted in the aim to repopulate areas where seagrass had been
lost from. There are problems they are attempting to overcome however, the main
one is that you cannot simple scatter seeds and allow them to grow as they
don’t remain in the same place. The team
working on this overcame this problem by using fabric bags which the grass
growths through keeping them in position until they become established before
the bag breaks down. This method also helps as it prevents the seeds from being
eaten by animals such as crabs.
There is still much work to be done in stopping the decline
of seagrass meadows and aid in their recovery.
Thanks for reading!
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