It was field trip day today
and we were all loaded on the bus for a tour of the Proserpine
River watershed. What is a watershed you ask, and what is
the Proserpine River? A watershed is the area of land that
is drained by a certain river and the Proserpine River is
our local river here that drains a large area of forest,
grazing land and sugar cane fields down to the sea. The
economic and cultural activities that occur in a watershed
affect the quality of the water that goes into the sea and
in turn affect the health of the Great Barrier Reef that
lies offshore. The bright corals of the Great Barrier Reef
can be choked by sediment coming down Australian Rivers
or overrun by algae fed by the nutrients dumped on the vast
sugar cane fields that end up in the river after a rain.
Sediment in the Proserpine River and other Aussie rivers
is higher than it once was due to gravel mines along the
river and cattle grazing that tramples streamside vegetation.
Corals can naturally remove a small amount of sediment from
their surface but are not equipped to handle the larger
amounts of sediment runoff occurring today. These sediment
clouded waters not only choke corals directly on their surface
but reduce the sunlight levels necessary for healthy coral
reefs. Algae can also be dealt with naturally by coral communities
through the grazing of herbivorous fish species such as
rabbitfish and surgeonfish. However, the fertilizer-laden
runoff from sugar cane farming has led to algae levels often
higher than the ecosystems can handle naturally. At the
mouth of the Proserpine River lie large communities of mangroves
- plants that can deal with large quantities of salty water.
These mangrove plant communities are home to populations
of the infamous Aussie salt water crocodiles. These beasts
can grow to 25 feet long and are the cause of numerous warning
signs along the coasts and rivers and at community boat
ramps. Mangroves harbor not only crocs, but act as natural
environmental filters removing many of the substances harmful
to the coral reef. For this reason they are among the most
important vegetation communities in Australia. Our tour
of the Proserpine watershed including some visits to gravel
quarries, grazing areas, and sewage treatment plants so
that we could get a grasp on the big picture of Australian
coral reef health. Unfortunately we did not see any man
or woman-eating crocodiles - that will come on our crocodile
safari on Friday - but we did see some mudskippers........
Tomorrow we head out on a for our first dive
on the Great Barrier Reef - an area of crystal clear water
harboring thousands of species of corals, fishes, molluscs,
echinoderms (starfish), and other creatures and located
50 miles off the coast of our coast here in Whitsunday,
Australia. It is hard to believe, but important to remember,
that what we will see owes its existence to the health of
the Proserpine River watershed and hundred of others like
it up and down the Queensland coast. |
