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Showing posts from August, 2012

Missouri Welcomes Isaac

As I walked to work, at 6 AM, the leading cloud bank from Isaac's massive pinwheel was drifting northward above Columbia.  Ahead of that cloud layer was the yellow-pink sky of dawn, giving the impression that the sun was about to rise on the northern horizon.

By 8 AM, the first rain showers arrived from the south and, for the past four hours, a steady rain has been falling across central Missouri.  Devoid of high winds or severe thunderstorms, this prolonged deluge is more than welcome in our parched State; if the current forecast is correct, we should enjoy intermittent precipitation through tomorrow afternoon, recharging the creeks, reinvigorating the plants and bringing our wetlands back to life.  Though too late to salvage most of this year's crop production, Isaac should put a modest dent in our prolonged drought and, hopefully, rescue the hayfields and grasslands.

As of early afternoon, the storm's center sits along the extreme western segment of the Arkansas-Missour…

The Meteorologist's Disclaimer

Meteorologists do not want human injuries or structural damage to result from the weather; after all, their job is primarily devoted to warning the public when dangerous conditions are expected to develop.  Then again, they live for hurricanes, tornado outbreaks and blizzards, pouring over their sophisticated radar reports and willing to spend hours refining and explaining their data to weather junkies.

Who can blame them?  After they spend weeks waving at fronts, urban temperatures and pressure gradients on a blue screen, severe weather gives them the chance to focus on storm dynamics and to perform for an attentive public.  While most citizens are content to check the forecast in the morning paper or on the local news, the threat of dangerous storms drives them to the Weather Channel and other national programs for regular updates and, for those interested, at least a modest degree of scientific meteorology.

As a physician, I understand the enthusiasm that meteorologists have for se…

Delta Blues

Molded by the glaciers and meltwater torrents of the Pleistocene, the broad Mississippi River watershed stretches from the Rockies to the Appalachians.  Over the past 2 million years, its major rivers and their numerous tributaries have carried vast amounts of sand and silt from the mountains, plains and Central Lowlands to the Gulf of Mexico, producing a massive delta of braided streams, coastal wetlands, tidal flats and sandbars.  Home to a diverse assembly of wildlife, from fish to mollusks to waders and sea birds, this rich ecosystem has also attracted humans, first drawn by the abundant food supply and later by the access to America's interior.

After damming the major rivers and attempting to inhabit the Mississippi floodplain, protected by a network of canals and levees, we have altered the delta ecosystem and have placed ourselves at the mercy of nature's relentlous cycle of inland flooding and tropical storms.  Deprived of nutrients and silt by the dams and levees, the…

The Sea of Cortez

During the Miocene Period, some 25 million years ago, rift volcanism began to develop in the region now occupied by extreme southeastern California, southwestern Arizona and northwestern Mexico.  This rifting was triggered primarily by a northern extension of the East Pacific Rise, a mid oceanic ridge that stretches across the southeastern corner of the Pacific Ocean.  Extensive faulting through this rift zone caused blocks of crust to drop below the adjacent terrain and, by 5 million years ago, the sea had invaded from the south. Augmented by the wet climate of the Pleistocene, the Colorado River swept enormous quantities of erosional debris into the northern end of this new sea, producing a vast delta that, today, obscures the connection of the Gulf of California Rift with faults of the Salton Trough and San Andreas network to its northwest.

Having torn the Baja Peninsula from mainland Mexico, this rifting, which continues today, transmitted pressure along the San Andrea Fault and a…

Never Mind!

For a week or more, many Americans, especially those in Florida, have been glued to the Weather Channel, anxiously awaiting every update on the progress of Tropical Storm Isaac.  While the expected tragedy seems to be unfolding in Haiti, primarily due to inadequate shelters and infrastructure in that country, most other reports have involved minimal impact from the storm to date.

Meanwhile, from the Expert Desk, computer models have been unrolled on a regular basis and, for the past several days, had generally agreed on a path along the west coast of Florida.  The only question was how severe the winds and storm surge would be and how disastrous Isaac would be for the Republican National Convention, in Tampa.  A great deal of focus was also directed to the risk of tornadoes and torrential rain across the Sunshine State.

This morning, all has changed.  The computer-generated cone of risk has shifted dramatically to the west, suggesting that the storm's impact across Florida (except…

Hurricane Anxiety

On this 20th Anniversary of Hurricane Andrew's landfall in Greater Miami, all eyes are on Tropical Storm Isaac as it spins in the Caribbean.  As of this morning, the storm seems to be losing its structure and now threatens the regional islands primarily with torrential rain.  This could be a devastating development in the tent cities of Haiti, where deforestation poses a major risk of mudslides and flooding.

According to their latest forecast, the Hurricane Center still expects Isaac to pass over Cuba and then enter the Gulf of Mexico.  If the storm does not fizzle over Cuba, the warm waters of the Gulf, combined with favorable upper level winds, may cause Isaac to strengthen into a hurricane along or near the west coast of Florida.  Whether it moves NNW along the Gulf beaches of Florida or heads more northwesterly toward the north-central Gulf Coast remains uncertain.

Of course, those of us with property along the Gulf  Coast hope that the storm remains offshore and does not stre…

Watching Al Jazeera

Like most Americans, I first became aware of Al Jazeera during the months following the September 11 terrorist attacks.  Based on reports from U.S. news organizations, it had the image of an underground network of jihadist sympathizers, known for their access to messages and videos from Osama Bin Laden. Never giving it much attention, I stumbled across an Al Jazeera broadcast several weeks ago while looking for something of value amidst the carnage of American cable channels.

To my surprise, it was a very sophisticated program, moderated from a massive, modern studio in Qatar; indeed, this Arab news organization was launched by the Emir of Qatar in 1996 and is still heavily funded by that government.  Watching for an hour or so, I viewed field reports from across the globe, including a few from the U.S.; rather than hearing the expected, negative rhetoric about America, I watched a report on our severe drought among other issues of concern to the average American.  While there was som…

A Message from Birds

Birdwatchers take up their hobby for a variety of reasons.  First and foremost, birds are colorful and interesting creatures that are represented by a wide variety of species.  Furthermore, in most regions of our globe, their population changes with each season, composed of local residents, migrants and rare vagrants.  This keeps us interested throughout the year and birdwatching appeases the hunting instinct that, to some degree, is found in all humans.

In addition, since bird populations vary from one ecological region to another, the hobby of finding and listing the varied species is a good excuse for travel and adventure, taking us to local nature preserves, State Parks, National Wildlife Refuges and, for some birders, to unique birdwatching sites across the globe.  Finally, the study of birds leads to a broader knowledge of their habitats, including the plants in which they nest and feed and the other wildlife species that share their environment.  In the end, we come to better u…

The Conservation Business

I assume that readers of this blog share my passion for habitat protection and wildlife conservation and, therefore, regularly donate to organizations that promote those causes.  However, I also assume that many of you, like myself, are dismayed by the weekly mailings and unwanted "gifts" that arrive from many of those organizations.  At times, I feel that the majority of my donations are consumed by this relentless solicitation and that, in fact, I am supporting an army of communication specialists rather than the conservation efforts that I hope to foster.

Of course, the organizations will cite the importance of their recruitment programs and likely have data to demonstrate the effectiveness of their mail campaigns.  Nevertheless, one wonders how conservation groups, mindful of deforestation and global warming, are so unconcerned about the tons of paper that they produce and the carbon footprint of their advertising and solicitation divisions.  A quarterly email would be f…

A Dry Wetland

On our first visit to the Forum Nature Area in two months, we found that our local wetland preserve is completely dry.  Thanks to the prolonged heat and drought, the seasonal lake is now a broad grassland and the hillside woodlands have taken on the yellow-brown foliage of a color-starved autumn.

Since the floodplain soil receives moisture from those uplands, the purple and gold wildflowers of late summer adorn the fields, including goldenrods, blazing star and thistles.  Cardinals, American goldfinches, yellow warblers and indigo buntings also offer their color to the parched landscape but the frog chorus has been stifled as resident amphibians and aquatic turtles have been forced into their winter retreats far too early.

Hopefully, late summer and early autumn rains will recharge the streams and rejuvenate the marsh.  For now, herons, rails and egrets have escaped to the Missouri River floodplain, summer ducks and geese  have flown off to deeper lakes and migrant shorebirds will hav…

Castle Rock Escarpment

From Quinter, Kansas, Castle Rock Road leads southward, toward the Smoky Hill River Valley.  Yesterday afternoon, I followed that even, dirt-gravel road as it undulates across the High Plains, now a mosaic of parched grasslands and dry stream beds.  Swainson's hawks perched on the phone poles, prairie falcons cavorted above the yucca-studded hillsides and a lean, juvenile coyote loped across the road as my pickup and its dust cloud approached.  About 5 miles south of Quinter, outcrops of Cretaceous sea deposits appeared along the creek valleys and, at 10 miles, the route to Castle Rock cuts to the east on a narrower but equally even road.  Another 4 miles brought me to the preserve entrance, which is on private land; after crossing a cattle guard, one can take a loop road past the Castle and its adjacent, spectacular escarpment (be aware that this road is deeply rutted and uneven, requiring a four-wheel drive vehicle with high clearance).

The Castle, composed primarily of Cretaceo…

Sea Floor Spreading

Sea floor spreading is the engine of Continental Drift, the heat-driven process that causes the geography of Earth's surface to undergo constant change.  This spreading occurs along a network of mid-oceanic ridges that lace the globe; separating tectonic plates, they do not necessarily run down the middle of our geographic oceans.  As the oceans open, the diverging plates cause other tectonic plates to collide, subduct or scrape along one another, lifting mountain ranges, igniting volcanoes and triggering earthquakes.

Spreading rates along these plate boundaries vary.  Divergence along the Mid-Atlantic Ridge, which does follow the general midline of that ocean, is among the slowest on Earth, averaging 2-3 cm per year, while that along the East Pacific Rise, which cuts across the southeastern quadrant of the Pacific Ocean, is 5 times that rate; indeed, the divergence between the Pacific and Nazca Plates, off the west coast of South America, is currently the most rapid sea floor spr…

Evolution on Mars

Now that Curiosity has safely landed on the surface of Mars, its future discoveries are greatly anticipated though, it seems to me, fairly predictable.  We already know a good deal about the Red Planet, including topographic evidence of past volcanism and stream erosion.  While specific details will unfold over the coming years, it is reasonable to assume that the evolution of Mars mirrored that of Earth during the first billion years of its history.

There is little reason to doubt that the same inorganic elements are found on both planets (though their relative abundance may vary) and that the early, tumultuous histories of Mars and Earth were very similar, including widespread volcanism and a gradual cooling of the planets' surfaces.  Despite its greater distance from the sun, Mars likely developed an Earth-like atmosphere while radiative heating and greenhouse gases offered temporary protection from the deadly chill of space.  Oceans formed as water accumulated in the geologic …

To Bury a Fox

Heading out to work on our Colorado farm this morning, I found a dead fox in the side yard.  It was the juvenile male that took up residence on the farm this spring.  Over the past two weeks, I have watched him trot along with a vole in his mouth, munch on our crop of apples and sniff his way across the pastures in search of other quarry.

On initial inspection, there was no apparent injury; I imagined he may have consumed something poisonous since he has had the habit of bringing baseballs, chew bones and other items in from neighboring properties.  Then, when I turned him over, I found a bloody gash across his chest, no doubt the handiwork of a coyote or older male fox.  If our farm was larger, I might have left him where he lie, a natural victim of nature's cycle.  I had no intention of calling the county wildlife patrol and have him end up in a landfill; neither could I leave him in place since the odor of decay would certainly annoy the locals.  So, despite the dry, hard-packe…

A Hummingbird Shower

Birdwatchers use a variety of means to attract hummingbirds; they are, after all, among our most attractive and fascinating birds.  Some of us use traditional feeders, filled with sweet, homemade nectar, while others plant a variety of flowering plants, such as trumpet vine, that hummingbirds visit.  Of course, a source of clean, fresh water is also effective, as with all birds.

Yesterday evening, while watering a row of chokecherries and lilacs, I discovered the most effective means of attracting hummingbirds that I had yet to experience.  Within a few minutes of spraying the shrubs with my patented thumb-pressure method, broad-tailed hummingbirds began to arrive from all directions, dipping through the mist or perching near the edge of the spray to cleanse their feathers.  At least ten individuals took advantage of the shower though only a few were bold enough to receive a thorough soaking; the latter group, relishing the downpour, were oblivious to my presence, offering a very clos…

Year of the Crabapple

Despite the heat and drought, this has been a good year for fruit production on our Littleton, Colorado, farm.  A mild spring, devoid of a late hard freeze, has led to large crops of apples, pears, chokecherries, wild cherries, Oregon grapes and mulberries; we've even had a fair number of apricots and peaches, an unusual occurrence since those trees bloom early, during the fickle weather of March.  But this year's productivity award goes to the crabapple trees, especially a large one next to our garage.

Loaded with more fruit than I have ever seen in an individual tree, the crabapple has started to drop its cargo early this year, likely in response to the hot, dry weather.  The small, hard, sour apples litter our backyard and every small breeze produces another windfall, drumming against the garage roof and pelting the ground like hail.  Yet, an abundant supply remains within the tree, glowing amidst the green leaves during the day and regularly thudding to earth overnight, of…

Basalt: Rock of the Ages

As the primordial Earth began to cool, almost 4.6 billion years ago, the magma across its surface was subjected to the planet's gravity and lighter elements and minerals moved upward, forming a layer of inorganic material that would eventually coalesce to cover 30% of the globe.  The other 70% would cool to form basalt, a more dense, fine grained rock, rich in silica, ferro-magnesium minerals and, in some regions, olivine.  The lighter elements formed the continental crust while basalt formed the oceanic crust; as heat currents evolved in the underlying mantle, the crust broke into tectonic plates, some of which were comprised of both continental and oceanic crustal segments.

Throughout the history of our planet and continuing today, basalt forms from magma along the mid-oceanic ridges and moves outward as oceanic crust on the diverging plates.  Should the oceanic plates move over a hotspot, produced by a mantle plume, basalt volcanic islands are produced; the Hawaiian Chain provi…

The Nature of Rocks & Minerals

Rocks, whether pebble or mountain sized, are composed of one or more minerals. Minerals are naturally occurring elements or chemical compounds with a unique crystalline structure; among these compounds are various sulfates, sulfides, halides, carbonates, nitrates, oxides, hydroxides, phosphates, silicates and others.  It is the chemical structure of a mineral that determines its physical characteristics, such as hardness, transparency, friability, color, luster, specific gravity, radioactivity and fluorescence.  To date, more than 3000 minerals have been identified on Earth; common examples include quartz, talc, dolomite, copper, gold, rock salt and hematite.

Rocks are broadly classified as igneous (having formed from magma), sedimentary (having formed from debris that settled in topographic basins, along stream channels or at the bottom of lakes and oceans) or metamorphic (igneous or sedimentary rocks that have been transformed by heat and pressure).  Granite is the classic example o…

Hunting Rocks

Having become enthused with agate collecting during our recent trips to Lake Superior, my wife and I have taken up the broader hobby of rock hunting.  While I have long been interested in geology, plate tectonics, natural history, rock formations and landscapes, my knowledge regarding specific types of rock has been lacking and this seemed like a good opportunity to broaden my education.

Heading to our Colorado farm, we thus took along a copy of Gem Trails of Colorado, by James Mitchell, to guide our collecting efforts.  Surprisingly, our first stop would be along the Republican River Valley on the High Plains of eastern Colorado, about 20 miles north of Burlington.  There we scoured the Tertiary and Upper Cretaceous sediments for agates, jasper, opals and other gemstones, eroded from the Rockies and carried eastward by large, meandering rivers; petrified wood may also be found in that area.  Today, we headed to Golden Gate Canyon, northwest of Golden, Colorado, where we searched outc…

Crossing Parched Terrain

Traveling across the Great Plains of North America can be monotonous at times but yesterday's journey was both depressing and worrisome.  The severe heat, intense sunshine and prolonged drought of this brutal summer have produced dry and yellowed grasslands, sunburned trees and barren crop fields.  The major streams are shallow and sluggish, farm ponds have given way to mudflats and the only greenery is provided by stressed riparian woodlands, roadside weeds, tangles of prairie sunflowers and, ironically, irrigated crop circles on the High Plains.  The Flint Hills of eastern Kansas, usually covered by olive grasslands and copious wildflowers in early August, were reminiscent of the Colorado Plateau, with its sparse vegetation and dry stream beds.

Birds were rarely encountered, save the occasional flock of vultures, among the few species to benefit from the deadly drought.  Cattle huddled in the shade of trees or billboards while goats and pronghorns were the only mammals that seem…

Send in the Clouds

We humans generally prefer mild, sunny weather but, after endless weeks of blazing sunshine, those of us in the Heartland appreciated the clouds that blanketed our region yesterday.  Triggered by an approaching cold front that brought severe storms to the Chicago area, the clouds did not provide much cooling but kept the intense sun at bay for most of the afternoon.

The rain, what little we received, arrived overnight and, unfortunately, skies are now clearing to the west.  Sunshine is forecast for the coming week though afternoon highs should remain in the nineties and morning lows will start dropping into the sixties.  What we really need is a prolonged period of wet, cloudy weather to resuscitate the vegetation, refill the ponds and recharge the streams but, heading into the driest months of the year, that is not likely to occur in the near future.

A glimmer of hope is offered by Tropical Storm Ernesto, now churning westward through the Caribbean.  While most forecast models take i…

Cave Men: Then & Now

Often depicted as hirsute, dim-witted creatures who lived in caves and survived by brute force, our ancestors deserve more respect.  As they spread out from Africa, about 80,000 years ago, they were clearly resourceful, creative and cooperative beings, every bit as intelligent as modern humans.  Indeed, those traits spawned their migration and ensured the survival of our species.  Were it not for their resilience, we would not be here to belittle their reputation.

One wonders how many modern humans would survive if suddenly deprived of modern technology.  We may have acquired a great deal of knowledge and built shining cities of glass and steel but, in the process, have lost many of the skills that were essential to our distant ancestors.  Sadly, we have also abandoned the cooperative spirit that gave them the courage to face the many challenges of life in the wilderness.

There are, unfortunately, modern cave men.  I am not referring to primitive tribes that, cut off from the commerce…

Flushing Out a Killer

Watering a flower bed last evening, I flushed out a praying mantis that was lounging in the black-eyed susans.  Crawling to the top of those summer blossoms, it waited out my disturbance, gently swaying to blend with the movement of the vegetation.

Though docile and fragile in appearance, the praying mantis, one of twenty mantids in North American, is a ferocious predator, snaring insects with its barbed forelegs.  Equipped with a highly mobile "neck," two large compound eyes and three simple eyes, this hunter is very adept at locating and catching prey as small as mosquitoes; it also feeds on larger victims such as crickets and grasshoppers (and juvenile mantids) and female mantises, larger than the males, are known to devour their suitor after (or while) mating.  Since they are also active at night, praying mantises often stake out a porch light, feasting on hapless months and beetles that are drawn in from the darkness.

Pregnant females deposit their eggs in a frothy tube…

Alaska's Collage of Terranes

As the Mesozoic Era dawned, 225 million years ago, only northern and northeastern Alaska were part of North America.  Since that time, numerous terranes and sub-terranes, have accreted to that primitive coast, producing the vast and varied landscape of present-day Alaska.

Many of these terranes, carried in on oceanic plates, were once part of other continents or sub-continents, having rifted away as new seaways opened.  Others formed as volcanic island arcs above subduction zones, either along the expanding coast of Alaska or elsewhere.  Still other terranes were composed of oceanic crust, trapped and lifted between colliding continental segments or scraped from the upper surface of a subducting oceanic plate.  Those terranes arriving from other regions of the globe were composed of rock much older than the sedimentary or volcanic rocks that formed along their margins at the time of accretion and possess fossils that provide clues to their site of origin. For example, the Alexander Te…