We All Belong to the Biosphere
Biosphere as Places to Live
Terrestrial Biomes and Watersheds
We often think of the Biosphere as primarily a Physical Place, a vast array of places to live, which in turn provide ways to make a living. The Biosphere place extends up into the atmosphere a few miles, where spores and spiderlings may be found, down into Earth's crust rock a mile or so, where some bacteria and archaea live, and all the way down to the ocean floor, beneath the crushing weight of miles of water. Life exists in boiling water, in hot springs on land and in black smokers on the ocean floor, and even in radioactive coolant water in nuclear reactors. Life is incredibly tough, tenacious and above all, inventive. Life finds ways to live in every conceivable place, except, maybe, lava during a volcanic eruption.
The availability of a place to live depends on the size of the organism. Bacteria are so small that billions can live in a cubic centimeter of soil or porous rock. Protists, most algae and protozoa, are microbes too, but much larger than bacteria, so many fewer can live in that space. Generally, the smaller the animal the more habitat is available, and the larger the population of that animal. This idea is has long been known as the pyramid of numbers. For every animal the size, say, of a deer, there will be a hundred or so the size of a mouse. Imagine, then, how many beetles the same place will support.
We tend to think of Earth as a kind of static stage where living organisms play out their lives, but this is not accurate. In fact, life plays a major role in creating the conditions that favor it. Cyanobacteria created the oxygen atmosphere; marine coccoliths generated the limestone that makes up much earth crust. The actors help create the stage.
In other words, over time, Life shapes the planet while the planet shapes Life.
To explore this see Biosphere as Process. See Adaptation.
Below are images of terrestrial Biomes. A biome is a kind of place to live, one type of ecosystem within the Biosphere. Each biome is unique, but to help us see the effects of rainfall, climate, and soil types around the land surface of Earth, we use biome names as typical of places such as grasslands and deserts, where in response to similar environmental pressures, plant and animal types have evolved to be similar in lifestyle and often in structure. Temperate grasslands and shrub-lands are called steppes in cental Asia, veldt in South Africa, prairies in North America, even though they are somewhat similar biomes.
The continents of Earth as a whole can be mapped by biome kind, as a rough guide:
Interesting, but wow! Some of those biomes are incredibly huge. But notice what happens when you zoom in on one continent, North America. What was all one color above turns out to be several biomes below. It's still a rough guide, but does suggest the true complexity of the places life thrives.
Zoom in again, on just one area of North America: what happens? Below is a biome map of the state of Arizona. Notice that once again, as you look closer and closer, apparent simplicity is replaced by complexity. This never stops. The living biosphere is very old, its flowering incrediibly complex, and this complexity is irreducible.
graphic courtesy Arizona Geographic Alliance
Notice that the biomes end abruptly at the state's boundary, and we don't know what happens over the border. We can only guess. Using political boundaries is not a useful strategy to comprehend biomes, nor can it help societies plan. Two other approaches are more useful--bioregions, and watersheds: both are concerned with landforms and water in relation to natural plant and animal communities.
Another way to see a biome is to see it from a different angle, literally. The evergreen boreal forest known as taiga is circumpolar. It circles the globe. Its conifers are similar or the same, pines and spruce, larches and cedars, and its deciduous alders and birches and aspens. Its quaking wetlands or muskegs grow the same sphagnum moss with assemblages of heaths such as blueberry, leatherleaf and labrador tea, and its acid soils grow bearberry and wintergreen. Many animals of the Eurasian taiga are the same species as in North American taiga, including the wapiti or elk, called red deer in Europe, the moose, called elk in Europe, the black bear, lynx, snowshoe hare, fisher and pine marten. Caribou of North America are Eurasia's reindeer. Timber wolves roam the taiga of Eurasia as they still do in some of North America's taiga. Bald eagles and ravens roam the circumpolar taiga as well. Like every biome now, the taiga is under multiple threats. Taiga provides sixty percent of logged wood on the planet, and logging is its greatest threat. As we cut forests without replenishing, we destroy huge carbon sinks, and inevitably release more carbon into the atmosphere.
|Bioregions & Bioregionalism
Bioregions have been largely ignored by governments except in Australia and the North American West Coast. The small nation and continent of Australia uses biogeographic regions as tools for learning, remediation of problems, and planning for the future.
Bioregionalism has the qualities of a social movement, and since it emphasizes Earth's actual realities rather than political boundaries and organizations, it tends to be dismissed by governments at all levels (except in California).
Bioregionalism suggests that the way people live within their habitat should be informed by knowing where your water comes from and where it goes, what its impact may be downstream, how local energy is produced and the effects of that. People should know what happens to their waste, and what its effects will be downstream. It further suggests that small is beautiful, and local is beautiful. Local ecology should be familiar, and should help determine daily choices. We should know the birds, animals, trees, plants and weather patterns of our places, as well as land features and soil types.We should rebuild our sense of community, get to know our neighbors and look out for each other. We should eat locally-grown foods, in season. Further, we should be directly involved in our children's education. In other words, bioregionalism is a positively radical movement. Bioregionalism wants us to fully inhabit our habitats, and stop living as if our lives were portable.
Probably the most ambitious bioregion, one that has been proposed with great energy, is Cascadia. It includes the coastal panhandle of Alaska, all of British Columbia, all of the states of Washington, Oregon and Idaho, and part of northern California. The logic of Cascadia is shared ecologies, watersheds, and the North America's west coast temperate rainforest. Its creation would mean merging parts of two nations and six states.
Proposed Cascadia Bioregion, based largely on watersheds and coastal forests
Political Overlay for Cascadia
Watersheds are clearly a critical aspect of every living system, whether at the scale of bioregions or local ecosystems and habitats. Basin, or drainage basin, is another name for watershed; in much of the world, the word watershed refers to the highlands that divide drainage basins, but in the US, watershed includes the land drained and the rivers that drain it, and the term divide is used to refer to the highlands.
Like bioregions, water ignores political and national boundaries, and given the struggle for potable water that is inevitable in the near future, a knowledge of your area's watersheds has become essential to making informed decisions. The Cascadia bioregion above includes many watersheds, including the Pacific Northwest watersheds of the Columbia River, the Snake, the Willamette, the Trinity, the Rogue, and more.
Tte graphic below presents a basic idea of 18 U.S. watersheds.
A state-level approach to watersheds is inevitably deficient, for basins and rivers have no politics. To picture the whole of California as one watershed is absurd. Below is a map of Minnesota watersheds, which is interesting but raises as many questions as it answers.
The map above fails to show is the directions of flow. It seems to be assumed. The Red River basin flows north into Hudson Bay, as does the Rainy River basin, shown in pink. The Great Lakes Basin flows east, down the Great Lakes and the St. Lawrence waterway into the Atlantic. All the rest flow south in the Mississippi River and end in the Gulf of Mexico.
A regional approach to watershed, below, shows the Upper Midwest and its water connections, and at least suggests that some rivers originating there flow into Lake Superior and eventually down the St. Lawrence and into the Atlantic, while others flow north into Canada, that flowage ending in Hudson's Bay, and the Mississippi/Missouri watersheds flow to the Gulf of Mexico. Like every aspect of ecology, it is the interrelationships that allow us to grasp understanding.
Terms like biome, bioregion, and ecosystem can be confusing, because they can be used at many levels. Their definition always depends on the context in which they are used. Look again at the biomes maps at the top of this page. Biomes change as you zoom in and out from general to specific and back again.
We are predisposed to think first of terrestrial (land) biomes, because they are our own. But remember that seventy percent of Earth is covered by ocean, and freshwater lakes and wetlands cover large areas of continents. Water is where life began, and lived for the first 2.5 billion years.
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