An Underwater World In Decline


Imagine you are in a forest and life is teeming around you.  The forest canopy stretches metres above and as you look up into the filtered sunlight a myriad of lifeforms can be seen living in their sheltered forest home.

No, it’s not a tropical rainforest; it’s an underwater world of Giant Kelps (Macrocystis).

The exceptional biodiversity of these Giant Kelp beds was first noted by Charles Darwin who visited Australia in 1983 and proclaimed, “The number of living creatures of all orders, whose existence intimately depends on the kelp, is wonderful”.

These large, brown algae are attached to the seafloor and are an important feature of many temperate reefs.  Buoyed by large, air filled bladders, they stand up in the water, and create a forest like environment, providing shelter and food for hundreds of species.

Macrocystis is limited to specific areas due to its preference for cool water and their need for rocky reefs to anchor themselves to.  In Australia, Macrocystis is confined to the southeastern parts of the mainland and Tasmania.

Global Distribution of Giant Kelp:

Climate change and the decline of Macrocystis:

Evidence suggests Giant Kelps are in decline.  The problem has been associated with the El Nino Southern Oscillation (ENSO) climate pattern, and contributing factors include changes in ocean acidity, increasing sea surface temperatures, more frequent storm surge events, and erosion of the coast.

Scientists believe the increasingly frequent ENSO phenomenon is driving warm tropical currents further south down the east coast of Australia where higher than normal water temperatures in partnership with lower nutrient availability, has seen a crash in Kelp populations, particularly in Tasmania.

Impacts on marine life are already apparent. Distributions of fish and other animals are shifting polewards and the timing of Antarctic seabird breeding and migration is changing, while some fish species previously only seen in Sydney are now being found in Port Phillip Bay.

How you can help

Everyone who cares about the health of our oceans can get involved by reducing their carbon footprint and working together to seek lasting global solutions to climate change.

The Great Ocean Road Coast Committee is currently undertaking a project on climate change and adaption strategies along the Surf Coast which commenced in April 2010.  You can investigate ways make a difference, and find further information at http://www.gorcc.com.au .

To get hands on in the battle against climate change, contact Surfers Appreciating the Natural Environment (SANE), a local community group that conducts environmental activities in the Bells Beach Reserve, on the 2nd Sunday of each month starting at 10:00am. Contact Graeme Stockton on 0425 752 648 or go to SANE’s website at www.sanesurfers.org.au.

This article was published in the Surf Coast Times as part of the publications fortnightly “Going Green Column”.

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