In The Land of the Black Bear Part 11

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Reflections: A Decade at Pheasant Lake

Pheasant Lake, Sixth Year, 1985. The Island reduced by the cattails. Only the deeper parts resist the encroachment of vegetation.

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Mounting on diaphanous wings, a swarm of organisms was emerging from the surface of the water, levitating erratically and taking flight into the half light of dusk as the Bushman approached the pond to feed an always hungry cohort of Rainbow Trout

in his charge. 

The Mayfly hatch one summer evening 4 years into the life of Pheasant Lake seemed to be the final element of validation for the micro-environment of the pond.

(See photos of Mayfly Hatch at the following link) 

   http://www.twincitiesnaturalist.com/search?q=Mayfly+hatch

 

 The Bushman had looked upon the results of the construction of a huge pond by a novice machine operator as a full-blown fluke. Skeptics in the neighbourhood had observed the project as it progressed with bemused curiosity. The many days of incessant bulldozer digging was dismissed as the foolish behavior of a greenhorn. In the end, according to the naysayers, the result would be an extravagant and expensive excavation for a sewage lagoon.

A happy conspiracy by an alchemy, which we describe as “nature”,  transformed the crude hole in the ground into a functioning ecological system in a very short time.  For a decade the Bushpeople watched the pond evolve. The first notable addition to the excavation was, of course water. Three quarters of an acre of excavation was filled with run-off to an average depth of 5 feet, the deepest part of the pond being between 12 and 13 feet. The bottom of the pond had been tapered gradually and sculpted to simulate the bottom of a lake.

Two months after the fish were planted into the newly formed pond, vegetation around the perimeter and in the shallow areas of the water made its appearance. Belted Kingfisher discovered the bounty of fish within the first six months. Cattails appeared soon after and given the richness of the fecal droppings of the fish, the cattails grew at an alarming pace. (See the evidence in the photos of Pheasant Lake from 1980-1985 above and below)

The abundant field of Cattails in turn appealed to the Redwing Blackbirds which found the environment to their liking and came to nest and rear their young. Soon the Bushman’s twice daily feedings to the trout became a gauntlet that he ran protecting his head, dodging the dive bombing Redwing Blackbirds defending their nests.

A smorgasbord of changes was unfolding around the pond: some, like the cattails were obvious, others like the mayfly hatch seemed miraculous although those changes had begun soon after the pond received its first charge of water in March and April of 1980 but would only appear years later when metamorphosis revealed itself.

Among the many transformations that occurred in the decade of the nineteen eighties one process seemed to defy the template of gradual, steady growth in the micro-environment. By the second year in the life of the pond, algae was present in mid-summer as a constant element. Algae in small clumps gave the pond a look of increasing authenticity: the look of a functioning ecosystem. Aquatic organisms abounded in the little floating masses of algae around the edges of the pond.

In mid-summer a combination of high summer temperatures, long days of sunshine in the North and excessive nutrients from the nitrogen based feed and droppings from the fish, transformed these small masses of algae into a green covering, a virtual lid,  over the total surface of the pond in sometimes less than two days: an algal bloom.

This explosive growth was of course unsustainable. Once the algae had used up all the nutrients in the water for its growth, the entire field of algae died overnight. In the morning the green covering had disappeared leaving crystal clear water. An unwelcome consequence of the death of the algal bloom was invariably the distressing presence of many fish at the surface of the water gasping for oxygen. The rapid composting of the now dead algae had depleted the oxygen from the water (a condition called anoxia) and the fish were in respiratory distress. Over the next hour or two, many fish died until oxygen could be reintroduced into the water or the fish died in sufficient numbers to allow the remaining fish to survive in the oxygen-poor water. (See the photo of Pheasant Lake the sixth year where a pump is aerating the pond to add oxygen.)

 From raw earth to complex ecosystem in the evolutionary blink of an eye; we witnessed the miracle of sudden transformation through vigorous growth and its downside, the unsustainability of unchecked growth, the two sides of a coin.

From microcosm (the pond) to macrocosm (the oceans of the Earth), do we dare extrapolate? Will the world’s oceans behave in a similar manner with higher temperatures and fertility increased by runoff from fertilizers from industrial farming and the fecal contributions from human global population explosion?

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Photos of the Evolution of Pheasant Lake in 1980-1985

(Click on a photo to start carousel)

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