Websailor's Wacky Wildlife World
Created | Updated Jan 21, 2009
A quirky look at wildlife. To be taken with a pinch of
salt, but with more than a grain of truth!
A Jelly Good Clean Up
No, it isn’t a spelling mistake, so do read on. Many governments, organisations and individuals are becoming increasingly concerned at the amount of carbon we are producing which is causing unnaturally rapid climate change.
So it was comforting this week, among all the gloomy news, to learn that the natural world is mobilising its own troops to combat the problem. The most obvious answer is, of course, to plant more trees. Even the most amateur student knows that trees absorb carbon dioxide and give out oxygen, not to mention stabilising rain and weather patterns. Underwater however, there are very interesting creatures that do an equally useful job of binding carbon, dumping it deep on the seabed out of harm’s way.
These are salps .
Small jelly like tunicates; barrel shaped or tubular creatures with a tough outer covering (tunic) and no backbone. There are some fifty species in various parts of our oceans. From tiny creatures to some as big as a peanut shell (monkey nut), they feed on
phytoplankton, drawing nutrient filled water in to their bodies as they swim, filtering out the nutritious phytoplankton and pumping out waste at the other end. The waste is in the form of carbon pellets which sink to the seabed. In vast numbers they can actually change the carbon cycle of our seas, and contribute to climate change in a beneficial way.
They feed alongside krill (small shrimp like crustaceans) and are often in competition for food, except that krill can feed under ice, where salps need open water. They are plentiful in most seas, following phytoplankton blooms to feed, but the greatest numbers are in the Southern Ocean where they form swarms. They can float singly or in long chains as much as 20 feet long, forming colourful and fascinating formations as they move. Synchronised swimming has nothing on them. To add to the spectacle many are luminous.
Sometimes they gorge themselves so much on readily available food that their 'digestive system' breaks down and they become clogged, ending up dying as they wash up in
slippery heaps on beaches.
To counteract this loss of numbers they can clone themselves, and they grow faster than any other multi-cell creatures. Recently a scientist suggested that these creatures, in sufficient abundance, could help solve our carbon dioxide problems as they clean up algae blooms soaked in carbon dioxide. He suggested that boosting nutrient levels in the seas would boost the population of salps and help cut carbon dioxide levels in the atmosphere.
However, other experts expressed serious worries about meddling with nature in this way. It seems to me, as an interested observer, that this creature regulates its own population according to available food supplies. Therefore moving deep water nutrients to the surface artificially to attract them could cause untold problems, upsetting the balance of the food chain among other things.
At night the salps swim to the surface to feed, swimming down into deep waters during daylight to avoid predators. When large enough, they produce hundreds of babies at once, coming out in strings of cells which divide into tiny individuals, all clones, but connected to one another. Several strings are produced with up to 1,000 clones, each of which in turn will have a single offspring of its own grown from a fertilised egg inside the mother. Once large enough they leave the parent.
This is where it gets strangely interesting. Once free of her offspring, the mother turns in to a male and fertilises other salp eggs! Both individual and chains of salps progress, eating constantly. To artificially boost their feeding seems to me to be asking for an explosion of these creatures beyond our comprehension and control. Already, salps gathering to feed can cover thousands of square miles.
In addition to salps it is being realised at last how important bony fish are to our seas and climate. Bony fish excrete large portions of inorganic carbon, and help to control the carbon cycle and balance the acidity of the oceans. Until recently it was believed that calcium carbonate came from microscopic marine plankton, being of fundamental importance to coral reefs and other marine ecosystems. Now, it is thought that between 3 and 15 percent of calcium carbonate, a chalky solid, comes from bony fish (but not sharks or rays) and is likely to have an even bigger impact on the future chemistry of our oceans than previously thought. Yet another reason for limiting fish catches, especially by-catches which destroy so much so wastefully. Allowing fish stocks to recover would have many advantages it seems.
As more and more research is done it becomes clear that we must limit our impact on the natural world and let it get on with the efficient job it is there to do. In the meantime let us enjoy salps, these miniscule wonders of the deep and be thankful for their almost secret existence.
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