While visiting Kenosha, Wisconsin, my childhood home, I noticed the waters of Lake Michigan we're very clear, almost crystal clear. Though this initially seemed like a good thing, the clarity is the result of the invasive zebra mussels, numerous enough to filter the entire water of Lake Michigan in 6 days. This is causing enormous ecological problems for the lake. The mussels filter phytoplankton, which are also the base of the food pyramid in the lake. Zooplankton feed on phytopylankton and the fish feed on the zooplankton.
Fish cannot survive in absolutely clear water.
(Chinese Proverb)
There is truth in that, because clear water is nutritionally poor.
A good example of that is the Waters of Lake Michigan which had become very clear in the last 20 years or so because of the invasion of the zebra mussel, which filters the water for phytoplankton.
Another example is the coral reef which, although teeming with life, the water is nutritionally very poor. Coral polyps have a mutual association with zooxanthellae, which are types of algae that live within the tissues of the coral. Zooxanthellae produce food through photosynthesis that they share with the coral polyps, and the coral have become so dependent on this food that the reef could not keep up with erosion without this extra nutrition. Of course coral polyps are filter feeders, but the waters around a coral reef being clear are very nutritionally poor. In recent years in Florida coral reefs have been dying from the silting of the water of coastal development, the digging of canals and such. The silt blocks off sunlight to the zooxanthellae and the coral polyps die from lack of nutrition. Interestingly, the coral reef derives its colors from the zooxanthellae, and nudibranchs also derive their color from feeding on coral.
The estuary, which is at the mouth of rivers or off the coast of tidal-flooded land is nutritionally very rich and, therefore, prolific with life, such as oyster beds.
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coluber2001
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Mon 7 Jan, 2019 12:58 pm
Incredible, never seen before footage of teeming life on the floor of the Antarctic ocean.
