Research and Field Study
The Sexy Sponge
When I first started SCUBA diving in New Zealand I was amazed by the variety of life underwater, with fish darting between rocks, kelp fronds tugged by currents, tiny crabs looking for food, and sponges of all shapes, sizes and colors anchored firmly to the bottom. Sponges, numbering over 8000 species, are common to many aquatic habitats from the Ross Shelf in Antarctica, Lake Baikal in Russia, rocky reefs in South Africa, to coral reefs throughout the Caribbean.
Sponges are critical to coral reef survival. Sponges filter and clean the water, provide shelter for commercially important species like juvenile lobsters, and are eaten by many fish and turtles. On many coral reefs, sponges outnumber corals, with sponges providing three-dimensional structure that creates habitat and refuge for thousands of species. Because of their large size and kaleidoscope colors, sponges help fuel the popular and lucrative diving and tourism industries. Although not always considered so, sponges are a "sexy" animal, worthy of public concern and scientific attention.
As climate change results in warmer, more acidic oceans, all marine life is potentially affected. It is well-known that coral health declines under these conditions, but the effect on sponge growth and survival is unknown. Significant declines in sponge health and biomass would be catastrophic to coral reefs, reducing water quality and severely impacting thousands of species from symbiotic microbes to foraging hawksbill turtles. A major loss of sponges would not only negatively impact marine life, but also local communities that depend on reefs for coastal protection and food.
Some sponges also have commercial value as "bath sponges". Before the mass production of "plastic sponges", people relied on natural bath sponges for washing and cleaning. Although fewer people use bath sponges today, there is still a substantial and growing global market. Because bath sponges grow quickly and are easily farmed using simple technology, with minimal processing and transport costs, bath sponge culture is ideal for underdeveloped coastal communities. Previous studies that I have led in collaboration with several coastal indigenous communities in Australia, have shown that bath sponges can be grown cheaply and easily using sustainable "low-technology" methods. These coastal communities are now establishing bath sponge farms to provide income and jobs to the local economy without harming the local reef environment. Bath sponge farming may also help improve water quality due to the ability of sponges to filter microbes, therefore improving the health of coral reefs.
Disney Worldwide Conservation Fund recently awarded Blue Ocean Institute a grant to study climate change effects on Caribbean sponges and identify hardy species that can be commercially farmed by coastal communities. This research, based in Panama, will start in the coming months and involve several field trips. Each field trip will be highlighted on Blue Ocean Institute's blog: http://blueoceannotes.wordpress.com/
Alan Duckworth
Research Scientist
