Rhythms of Change in Rocky Mountain National Park by Ellen Wohl

Author:Ellen Wohl [Ellen Wohl]
Language: eng
Format: epub
ISBN: 9780700623372
Publisher: University Press of Kansas
Published: 2016-11-15T00:00:00+00:00

There Is No Away

The wind picks up and small whitecaps appear on the lake. As summer develops in the park, winds and moisture come increasingly from the east. Warm, moist air flowing inland from the Gulf of Mexico across the Great Plains rises abruptly as it meets the Front Range. Air rising from the plains carries more than just water vapor. Atmospheric transport gives a new meaning to the old song title that “It’s a Small World, After All.” Dust stained rust-red with iron oxide travels from northern Africa and falls on England as blood rains. Some of the dust also crosses the Atlantic to fall on Caribbean coral reefs, adding nutrients to the coral ecosystem, but also carrying a type of fungus that can infect the corals. Dust from the Gobi Desert crosses the entire Pacific and penetrates as far eastward within North America as Denver, causing air quality to fall below federal standards. Closer to home, dust from the Great Basin and southwestern United States settles on the snowpack in the Rockies, causing the snow to melt more rapidly.

The concentration of people and domestic animals living at the eastern base of the Colorado Front Range creates one of the most important sources for atmospheric deposition of nitrogen in the national park. Over the past century, human activities have caused enormous increases in the amount of nitrogen entering rivers and emitted into the atmosphere. We spread nitrogen lavishly on our croplands and from there the nitrogen washes into rivers and the ocean. Nitrogen comes out of the tailpipes of our vehicles and the smokestacks of our factories. The cumulative effect is much greater environmental concentrations of nitrogen since 1950, both globally and in the area around Rocky Mountain National Park. By the start of the twenty-first century, the proportion of total nitrogen introduced to the atmosphere as a result of human activities exceeded that produced naturally.

Nitrogen is an essential element for all living organisms but, as with other nutrients, too much nitrogen can create problems. In most natural environments, the presence of relatively small amounts of nitrogen limits the abundance of organisms such as algae that can directly utilize it. But when nitrogen falls from the sky in sufficient quantities, the algae feast and algal populations boom. A wealth of algae is bad news for many aquatic environments, including rivers and lakes. The algae take up other nutrients needed by plants and animals. More importantly, when the algae die, they sink to the bottom of the water body and decompose in a process that extracts dissolved oxygen from the water. Depleted oxygen levels can kill fish and other aquatic life, creating a condition known as eutrophication.

Eutrophication is now widespread in estuaries and nearshore zones such as the Gulf of Mexico. Increased nitrogen deposition can also affect high-elevation lakes and alpine and subalpine plant communities. The lakes experience eutrophication as floating algae populations increase. Increasing nitrogen concentrations in the water of Loch Vale and other lakes in Rocky Mountain National

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