Sponging a living

March 4th, 2016

Micrograph of the bryozoan Flustra

The Bay is home to a vast army of locals, who have survived and adapted to a landscape that appears at first glance to be empty… At our talks on the 10th February we investigated the most overlooked creatures of the Bay. The couch-potatoes. These are animals that, having found a place suitable to put down roots, have stopped there for the rest of their lives. They rely on the tides of the Bay to bring food to their waiting mouths.

The ecosystem of the Bay is driven by phytoplankton blooms, which are at their most extensive in Spring and Autumn. For the rest of the year plant life is comparatively scarce. In this environment our ‘couch potatoes’ play a vital role; every bacterium, every gram of poop, anything that can be recycled is brought back into the food chain. Despite their sedentary nature, these filter feeders are an essential part of life in the Bay.

This intensive re-use of all things organic has, unfortunately, an unexpected side effect. Organic toxins, such as PCBs (banned in the seventies) are held within the marine food web, and are responsible even today for the deaths of top marine predators, such as dolphins and killer whales (See for example: BBC report by Rebecca Morelle).

This sobering fact leads us some way towards our last talk of the Winter series in the Gregson – ‘Human Impact on the Bay’ on Wednesday 9th March. At this meeting we will look at a couple of the ways we impact the life of the Bay, through Fisheries and litter.

More information: Human impact on the bay PDF 77kB

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