Chemists of Air

There are so many amazing facets of nature that tend to slip by unnoticed. Think about the last time you walked in the woods. Where was your attention? Did you think about the trees, the landscape? Or maybe the organisms you either could see and hear or that you imagined might be nearby? Did your gaze ever pause on the rocks or tree trunks encrusted with the inconspicuous forms of lichens?

When you do notice lichens, their difficult, astonishing existence becomes apparent. Lichens occur in the most inhospitable places: on trees, rocks, and roof shingles; in extremely cold environments like the Arctic and Antarctic; and even as crusts on top of desert soil. How is it that this organism–is it a plant? A fungus?–can survive where so many others cannot?

Jane Hirschfield’s poem, “For the Lichens,” is a journey of awareness. The speaker knows about the trappings of cities, but the discovery of lichen opens up a world she hadn’t known existed:

Back then, what did I know?
The names of subway lines, buses.
How long it took to walk twenty blocks.

Uptown and downtown.
Not north, not south, not you.

When I saw you, later, seaweed reefed in the air,
you were gray-green, incomprehensible, old.
What you clung to, hung from: old.
Trees looking half dead, stones.

Hirschfield hints at the answer to one of our questions when she calls lichen “seaweed reefed in air.” As it turns out, lichen is often both a plant and a fungus; it is a stable association between a fungal body and a photobiont, that is, a symbiotic partner capable of photosynthesis. Most commonly, the photobiont is an algae, but sometimes that role is filled by cyanobacteria, an ancient form of photosynthesizing bacteria.

Symbiosis, in biology, is an interaction between two organisms that is beneficial to both. When the photobiont in the partnership is algae, the fungal body protects the alga, and the alga provides food through the process of photosynthesis. When, instead, the partner is cyanobacteria, it performs photosynthesis and also nitrogen fixation, taking nitrogen from the air and making it available to the fungus. These interactions greatly increase the range of both organisms, allowing them to survive in environments that neither could handle alone.

Marriage of fungi and algae,
chemists of air,
changers of nitrogen-unusable into nitrogen-usable.

Like those nameless ones
who kept painting, shaping, engraving
unseen, unread, unremembered.
Not caring if they were no good, if they were past it.

Reproduction in lichens can be as complicated as you might imagine for a body composed of two symbiotic organisms. Certain lichens can reproduce asexually, either vegetatively through broken-off pieces or with structures called soredia, little bundles of algal cells surrounded by fungal threads. A few kinds of lichen can reproduce sexually, though it should be noted that only the fungal body is actually reproducing in these cases; after germination, a suitable photobiont must be found to form a lichen. In sexual reproduction, two different kinds of spores are produced (they can be loosely thought of as “male” and “female”), which meet and combine genetic material.

The body of a lichen, called the thallus, is a combination of algal and fungal cells. General body form, determined largely by the fungus, fits into one of three classifications: crustose lichen occurs as a crust on a surface, often rocks; foliose lichen appears leafy and lobed; and fruiticose lichen has upright, branchlike structures. The final stanza of Hirschfield’s poem begins by listing images inspired by lichens:

 Rock wools, water fans, earth scale, mouse ears, dust,
ash-of-the-woods.
Transformers unvalued, uncounted.
Cell by cell, word by word, making a world they could live in.

What an incredible feat, to change the environment to make it more suitable for yourself! What organism, besides humans, can manipulate its world to such a dramatic extent? And yet, this complex interaction of fungus and algae is occurring all the time in a nondescript little package. So the next time you’re outside, look a little closer at your surroundings. Try to remember the intricacy of what is all around you, worlds within worlds.

REFERENCES

“For the Lichens” by Jane Hirschfield, published online by The Atlantic. Read it here. 

“Lichen Biology” University of Sydney’s School of Biological Sciences Online Learning Resource. Link. 

“Lichen” 15 October 2008. HowStuffWorks.com. Link.

Sex, which breaks us into voice

Photo by David Berkowitz.  http://commons.wikimedia.org/wiki/File:Galapagos_Tortoise_Mating.jpg

Photo by David Berkowitz, Wikimedia Commons

In all of nature, the tortoise is one of the most unlikely animals to be featured in a poem about sex. Yes, of course they are sexually reproducing organisms, and therefore in order for reproduction to occur, there must be an act of sex, but…tortoises? One curious aspect of the tortoise mating system is that it includes vocalizations. And not just any vocalizations: emphatic, rhythmic, sometimes roaring, sometimes human-like sounds. For an animal as, well, quiet as a tortoise, these vocalizations are definitely interesting. And to DH Lawrence, inspiring.

I thought he was dumb,
I said he was dumb,
Yet I’ve heard him cry.
 
First faint scream,
Out of life’s unfathomable dawn,
Far off, so far, like a madness, under the horizon’s dawning rim,
Far, far off, far scream.
 
Tortoise in extremis. 
 

The name “tortoise” generally refers to any land-dwelling, non-swimming member of the order Testudines (members of the order as a whole may be called “turtles”). All members of this order are characterized by a shell made of dermal bone that encases their organs and limb girdles (where the limbs attach to the trunk). The top part of the shell is called the carapace, the bottom part is the plastron, and the piece that connects the two is called the bridge. Though Testudines was once incredibly diverse, today only 260 species from 13 families remain.

I can't not include an image of "Chelonia" from Ernst Haeckel's Kunstformen der Natur, 1904

“Chelonia” from Ernst Haeckel’s Kunstformen der Natur, 1904

Tortoises, the land-dwelling subgroup of turtles, belong to the family Testudinae. They range in size from a few centimeters to two meters, and are one of the the longest-lived animals in the world; some individuals have been known to survive more than 150 years. Their age can be estimated by the concentric rings on the carapace, though this is not a definitive method.  Many species of tortoise are sexually dimorphic, which means that males and females have obvious physical (morphological) differences. Females tend to be slightly larger, and have shorter tails. In some species, females also have longer claws. Males often have longer tails, longer neck plates, and a plastron that is curved inward.

Which brings us to sex.

Male tortoise, cleaving behind the hovel-wall of that dense female,
Mounted and tense, spread-eagle, out-reaching out of the shell
In tortoise-nakedness,
Long neck, and long vulnerable limbs extruded, spread-eagle over her house-roof,
And the deep, secret, all-penetrating tail curved beneath her walls,
Reaching and gripping tense, more reaching anguish in uttermost tension
Till suddenly, in the spasm of coition, tupping like a jerking leap, and oh!
Opening its clenched face from his outstretched neck
And giving that fragile yell, that scream,
Super-audible,
From his pink, cleft, old-man’s mouth,
 

In tortoise mating, the female is on the bottom. The curvature of the male’s plastron fits neatly over the female’s carapace, enabling them to achieve the proper intimacy. Female tortoises have what is called a cloacaor vent, which is a single opening that serves both excretory and reproductive functions. Male tortoises also have cloacas, but within the cloaca is a hydraulic intromittent sexual organ, otherwise known as a penis. While tortoise penises are anatomically comparable (and evolutionarily convergent) to those of mammals, they can have dramatically different shapes and features. Some are pointed, some are flat, and some look like opening flowers. The penis is often disproportionately large (and by that I mean half the length of the plastron or more). Most likely these shapes and lengths have evolved in order to ensure genital contact with the female.

But what guides DH Lawrence’s poem is male tortoise vocalization during the act of mating. Tortoises rarely emit sounds, so when they do, it  is meaningful. Most likely, these vocalizations are auditory signals to females. It is thought that producing these sounds is energetically costly to males, so males who can produce more calls may be of higher quality. In Hermann’s tortoises, females have been shown to respond to recordings of male calls, and to prefer higher-pitched and faster rates of calling. In marginated tortoises, male mating success is positively correlated with the number of calls emitted during mounting. So the ability to produce these calls is advantageous to males.

His scream, and his moment’s subsidence,
The moment of eternal silence,
Yet unreleased, and after the moment, the sudden, startling jerk of coition, and at once
The inexpressible faint yell —
And so on, till the last plasm of my body was melted back
To the primeval rudiments of life, and the secret.
 
So he tups, and screams
Time after time that frail, torn scream
After each jerk, the longish interval,
The tortoise eternity,
Agelong, reptilian persistence,
Heart-throb, slow heart-throb, persistent for the next spasm.
 

 In “Tortoise Shout,” DH Lawrence recognizes something undeniably human in the call of the male tortoise. Strange as these creatures are, we share their reliance on sex, and more, the seeming enjoyment of the act. Lawrence hears the tortoise calling from the “horizon of life,” and it affirms his place in the universe by reminding him of our connection with all sexual beings.

Sex, which breaks up our integrity, our single inviolability, our deep silence
Tearing a cry from us.
 
Sex, which breaks us into voice, sets us calling across the deeps, calling, calling for the complement,
Singing, and calling, and singing again, being answered, having found.
 
 

REFERENCES

Galeotti, Paolo et al. 2004. Female preference for fast-rate, high-pitched calls in Hermann’s tortoises Testudo hermanni. Behavioral Ecology 16(1): 301-308. Link. 

Kelly, DA. 2004. Turtle and mammal penis designs are anatomically convergent. Proceedings of the Royal Society of London B 271 (Suppl 5), S293-S295. Link.

Lawrence, DH. “Tortoise Shout.” Read it here. 

McCurry-Schmidt, Madeline. 2011. “How turtles do it.” Link.

Meylan, Peter. 2012. Testudines: Turtles, Tortoises, and Terrapins. Tree of Life Web Project. Link. 

Niash, Darren. 2012. Terrifying sex organs of male turtles. Link. 

Sacchi, Robert et al. 2003. Vocalizations and courtship intensity correlate with mounting success in marginated tortoises Testudo marginata. Behavioral Ecology & Sociobiology 55:95-102. Link. 

Tortoise Calls: recordings by the California Turtle & Tortoise Club. Link. 

Because the wolves are shot

coyote

What do you really know about coyotes? Maybe you’ve heard the official line about the economic consequences of coyotes killing livestock. Maybe you know of a neighborhood cat that was taken. Maybe you’ve heard conservation groups protesting inhumane treatment of these animals, or recall Mark Twain’s “slim, sick, and sorry-looking skeleton…a living, breathing allegory of Want.” In reality, these animals are neither good nor evil, but are simply trying to survive the best they can in a world that is changing around them.

And as the coyote turns the cat to sweetness
in its mouth, a month-long stint of apricot
pit-, ant-filled scat, a month before of
birdseed, cricket, crappy sandwich; so,
 
don’t turn your back; befriend them; grab
and wave a stick; the twenty doses meant to still
their little ones were killed inside coyote,
and outcome: snapping infant death: your indoor
 
dogs, and bitten, squalling children
 

Karen Leona Anderson’s poem “Coyote” begins with a list of found items a coyote has eaten. Coyotes are omnivores and scavengers, meaning that they can and will eat just about anything.  Though they have a bad reputation as killers of sheep, chickens, and deer, coyotes also eat snakes, foxes, rodents, pet cats, sandwiches, and garbage, for a start. This could be the key to this species’ success in a country where the large predators are either killed outright or squeezed out by human population growth.

Which isn’t to say the coyote isn’t targeted. They are one of the most vilified animals in North America. The Wildlife Services division of the US Department of Agriculture specializes in “predator control,” killing thousands of predators to protect livestock and big game. The most common predator killed (at an estimated 512,500 between 2006-2012) is the coyote. Outcry by biologists and the public as well as a series of articles by Pulitzer-prize winning journalist Tom Knudson led to ongoing investigations into this organization.

The problem with killing coyotes is that in some systems they act as keystone predators. Remember ecology: everything (plant, herbivore, carnivore) is connected to everything else in the food web. When part of the web is removed, it affects every other organism that was connected to it. A keystone, literally, is the stone at the top of an arch that holds up the entire structure. A keystone predator, then, is at the top of the food web. When it is removed, the delicate balance between interacting species is destroyed.

edu_food_web

Removal of coyotes has an effect on smaller predator (mesopredator) populations; in the absence of coyotes, populations of animals such as raccoons and foxes (and housecats!) increase dramatically. These mesopredators then consume far more eggs, birds, mice, voles, and other small animals than they should, and the populations of these prey organisms plummet. (Housecats in particular decimate bird populations. More information here.) In a cascade effect, whatever plants or insects the birds or mice feed on are then released from predator pressure, and they, in turn, multiply. Replace the keystone predator in the system, and order is restored. This is called top-down regulation: maintaining the balance of the food web below and around the top predator.

dens
in rainpipes, basements, crawlspace, tenants’ dumpsters:
a fed coyote is a dead–what? Since they ate
even the stinging sugar-eaters, since when
 
they couldn’t eat they bred into your pets
a coyness, slipped behind the fence, endorphins,
dopamine sweeter than the kibble
                                                   –so what’s to want?
 

Whereas in the west, wolves, bears, and mountain lions act as apex predators, these animals have been almost entirely extirpated from the eastern US. In response, the sly coyote, omnivorous and adaptable, has taken the role formerly held by wolves. Genetic studies have shown that quite a few eastern coyotes are, in fact, coyote-wolf hybrids. As a result, they are larger than their western counterparts, and are behaviorally more wolfish. Unlike wolves and other large predators, however, coyotes aren’t picky about forests and open space. They easily adapt to live in suburban and even urban areas where food is abundant. Chicago, for example, has tracked hundreds of coyotes living in the city for the past 14 years, thriving off of the rodent population.

Though originally pushed out of rural areas by human expansion, biologists say that coyotes are equally at home in the city. They pose no danger to us so long as we allow them to remain wild. This means not feeding them, being sure to pick up your garbage, and taking pets inside at night. Don’t be so quick to judge an animal that is only surviving. Remember that every species has its part to play, and that designations of good or evil are restricted to those of us with morals and a conscience.

With eyes like lanterns out by the latticed gate,
a future soft-tanned pelt pulls up
and moves to the city, deceitful little trot,
about to whelp and, honey, because the wolves
 
are shot and wildcats museumed and moth-torn,
the city, hareless, knows it’s gone to them; omnivorous
I tell myself, so make yourself their home.
 
 

REFERENCES:

“Agriculture’s Misnamed Agency.” 2013. The New York Times.  Link.

Cart, Julie. 2014. “Congressmen question costs, mission of Wildlife Services agency.” Los Angeles Times. Link.

“Coyote: Canis latrans” by Karen Leona Anderson, from the collection Punish Honey. Buy it here.

The Humane Society. 2013. “Why Killing Coyotes Doesn’t Work.” Link.

Knudson, Tom. 2012.  Wildlife Services’ deadly force opens Pandora’s box of environmental problems.  The Sacramento Bee.

Stolzenburg, William. 2008. Where the Wild Things Were. Bloomsbury.

“Urban Coyote Ecology and Management.” The Cook County, Illinois, Coyote Project. Link.

USDA Publication. 2011. “Coyotes in Towns and Suburbs.” Link.

Way, J G. 2007. Suburban Howls: Tracking the Eastern Coyote in Urban Massachusetts. Dog Ear Publishing, Indianapolis, Ind.

THANKS:

Special thanks to Karen Leona Anderson for permission to use her work.  Please check out her lovely collection of poetry, Punish Honey, available here.  More information on Dr. Anderson is available here.

Our blood too rich

mosquito_cropped

I choose today, when most of us in New England are sunk under wet snow and dreaming of the hot, humid days of summer, to remind you that every season has its dark side.  When the sun is beating down on us and moisture in the air suppresses our every movement, we will fall prey to a ubiquitous pest that everyone recognizes: the mosquito.  Last year’s wet spring left plenty of standing water for breeding, and the resulting swarms were, in some places, intolerable.  But why do these insects behave the way they do?  How do they find us?  Why do they require our blood?

First came the scouts who felt our sweat in the air
and understood our need to make a sacrifice.  
 
We were so large and burdened with all we had carried
our blood too rich for our own good.  
 

Alison Hawthorne Deming’s poem, “Mosquitoes,” examines the interaction between mosquitoes and humans in a slightly different viewpoint than we are used to.  Most often, humans view mosquitoes as pests, disease-bearing annoyances that inhibit our enjoyment of the outdoors in summer.  Instead, the speaker in this poem views us as a sacrifice, burdened with rich blood ripe for the taking.

There are over 2,700 species of mosquitoes in the world, and all of them require water to breed.  Most eggs overwinter and hatch into larvae in the spring.  Larvae eventually grow into pupae, which after one to four days form a pupal case, within which they metamorphose into adult mosquitoes.  Their purpose now is to mate and feed.

Female mosquitoes are the attackers.  (Males live only a few days after mating, surviving on plant nectar.)  Protein obtained from ingesting blood aides the female in development of eggs.  The mosquito requires a blood meal each time she lays eggs, and can live anywhere from days to weeks, repeating the process of feeding and laying eggs many times.  The eggs hatch or overwinter; the cycle resumes.

Then came the throng encircling our heads like acoustic haloes
droning with the me-me-me of appetite.
 

Several factors have been shown to attract mosquitoes, including: perspiration, heat, light, body odor, lactic acid, and carbon dioxide.  When a female lands on a likely victim, she sucks blood with her proboscis, or feeding apparatus.  There are actually six mouthparts contained in the female’s needle-like proboscis.  The outer sheath is the labium, which bends back to allow the two pointed mandibles and two serrated maxillae to penetrate the skin.  Mosquito bites are generally not very painful because the jagged shape of the maxillae results in a low surface area and a minimum of contact with nerves in the skin.  On the basis of this finding, a Japanese scientist has recently designed a nearly-painless hypodermic needle modeled after a mosquito’s maxilla.

Once the maxillae and mandibles have entered the skin, the mosquito pumps her own saliva into the wound through a hypopharynx, while the tubular labrum allows her to suck blood into her own abdomen.  The saliva contains an anticoagulant, ensuring that blood flow is continuous through the meal.  Itching after a bite is due to our natural immune response to the mosquito’s saliva.  Even after the swollen wheal disappears, the itch remains until your body has broken down the proteins in the saliva.

We understood their female ardor to breed and how little
they had to go on considering the protein required to make
 
their million-fold eggs.  Vibrant, available, and hot,
we gave our flesh in selfless service to their future.  
 

So think of this as you complain about winter.  Remember that summer is coming, and with it, the mosquitoes.  Prepare yourself as a sacrifice.

REFERENCES:

Coxworth, Ben.  04.04.2011.  “Mosquito inspires near-painless hypodermic needle.”  Gizmag.com

Darsie, RF, Jr. and RA Ward.  1981.  Identification and Geographical Distribution of Mosquitoes of North America, north of Mexico.  Fresno, CA: American Mosquito Control Association.

Freudenrich, Craig.  “How Mosquitos Work.”  Howstuffworks.com

“Mosquito Biology.”  Alameda County Mosquito Abatement.  Link. 

“Mosquitoes.”  Alison Hawthorne Deming.  Read it here.

Sutherland, DJ.  2013.  “Mosquitos in Your Life.”  Rutgers School of Environmental and Biological Sciences: Department of Entomology page.  Link. 

They flutter, shake like mystics. They materialize.

bat

Few creatures have attained the ability to evoke utter terror like the bat.  What is it about this flying mammal that has resulted in such a stigma of filth, disease, and horror?  Paisley Rekdal’s poem, “Bat,” begins by depicting a bat at rest, but by the final lines, the nightmarish language has drawn the reader into a paranoid fantasy.  The title acts as the first line in this work, which begins:

“Bats
 
unveil themselves in dark.
They hang, each a jagged,
 
silken sleeve, from moonlit rafters bright
as polished knives.  They swim
 
the muddled air and keen
like supersonic babies, the sound
 
we imagine empty wombs might make 
in women who can’t fill them up.”
 

So in the opening stanzas alone, bats have evoked moonlight, knives, “supersonic babies,” and infertile women.  This rich, dark symbolism had to have begun somewhere, but where?  Why is the bat often feared and hated by humans?

Bats are the only mammals capable of true, sustained flight.  Their wings are unlike birds’ wings; in fact, the bones in a bat wing are homologous to those in a human hand, which means they are alike in structure because they descended from a common ancestor.  Between the “hand” and body of the bat, and between each finger bone, is a thin membrane of skin called the patagium.  The “thumb” of the bat projects from the top of the wing in a claw, allowing bats to climb.  As a result of these features, bats belong to the order Chiroptera, which in Greek means “hand-wing.”

Most bat species are only active at night, and spend daylight hours hidden away in caves, under bridges, in chimneys, or in trees.  Because of their nocturnal habit, most bats have evolved a system called echolocation, which uses soundwaves to navigate and find prey.  In brief, the bat produces ultrasonic sounds and listens for the echos bouncing off of objects in its path.  By interpreting the speed and intensity at which the echos return, the bat creates a detailed image of its surroundings.  With echolocation, bats can judge the size, distance, and direction of movement of small objects like insects.  Some bats make these sounds with their mouths, while others use their noses.  It is thought that the strange nose structure (called a leaf) in some tropical bats serves to help focus the sound for accuracy purposes.

"Chiroptera," from Ernst Haeckel's Kunstformen der Natur, 1904.

“Chiroptera,” from Ernst Haeckel’s Kunstformen der Natur, 1904.

“A clasp, a scratch, a sigh.
They drink fruit dry.
 
And wheel, against feverish light flung hard
upon their faces,
 
in circles that nauseate.”
 

It seems likely that the mistrust and fear of bats stems initially from their appearance and behavior.  They only come out at night, can fly, emit strange noises, and some even drink blood!  European cultures have long associated bats with witchcraft, black magic, darkness and evil, and this animal has suffered negative connotations in works from Shakespeare’s Macbeth to Bram Stoker’s Dracula.  In Mesoamerica, bats symbolized the land of the dead, destruction, and decay.   A fear of bats even has a title: chiroptophobia.

The myth of the vampire is based in fact.  There are, however, only three species of vampire bat in the world, and those live in Mexico, South and Central America.  In addition, two out of these three species only drink the blood of birds (the third drinks mammalian blood, but prefers cattle to humans).  Unlike the movies, they do not suck their victim’s blood: rather, they prick the animal and lap up the blood.  The bats’ saliva contains an anticoagulant that prevents the blood from clotting.  This enzyme is useful to humans, as well: it is used to treat human stroke victims.

Another major fear inspired by bats is of rabies.  While it is true, that some bats carry rabies, only a very small percentage do, and it is impossible to contract rabies by merely seeing a bat or being in the same room as one.  That being said, if you are bitten by a bat (or by any other wild mammal, ever) tell your doctor.  If the animal can be captured and tested for rabies, it will provide peace of mind.

Fear of rabies has caused a lot of unnecessary destruction of bats and bat colonies.  This does not only disrupt the ecosystem, but affects us as well, since the presence of bats is quite beneficial to humans.  Most species are insectivorous (eat insects), and consume some very damaging pest species.  Many others act as pollinators for both wild and cultivated plants, including bananas, peaches, durian, cloves, and carob.  Fruit-eating bats play a role as seed dispersers, and in some clear-cut forests, up to 95% of first new growth can be attributed to bats.  Bats have also been shown to disperse the seeds of avocados, dates, figs, and cashews.

So bats may look scary, and they may act strange or unnatural, but in truth they are generally harmless, beneficial animals; animals that continue to be incredibly misunderstood.  As with many other wild animals, bats are more afraid of you than you are of them.  The next time you’re out at night, try to remember this when, without a sound, those silent wings swoop downward toward you before you can react.  Enjoy your fear, but don’t allow it to guide your actions in the waking world.

“Imagine one at breast or neck,
 
Patterning a name in driblets of iodine
that spatter your skin stars.
 
They flutter, shake like mystics.
They materialize.  Revelatory
 
as a stranger’s underthings found tossed
upon the marital bed, you tremble
 
even at the thought.  Asleep,
you tear your fingers
 
and search the sheets all night.”
 
 

REFERENCES:

Harris, Tom.  2001.  “How Bats Work.”  Howstuffworks.com.  Link.

“Learning about bats and rabies.” Centers for Disease Control and Prevention.  Link.

“Myths and Facts.” Bat World Sanctuary.  Link.

Rekdal, Paisley.  “Bats.”  Read it here.

Tuttle, Merlin D.  2011.  “All About Bats.”  Bat Conservation International.  Link. 

THANKS:

My personal bat guru, Laura Cisneros, provided fact-checking and proofreading of this post.  Any mistakes or inaccuracies are my own.  Laura is a PhD student researching the effects of human-modified landscapes on different aspects of bat communities.  Results of her research identify characteristics of these landscapes that maintain a diversity of bat species and increase the probability of maintaining vital ecosystem services (e.g. pollination) provided by bats.  As she writes,

“Have you ever looked out of an airplane window and noticed the intricate patchwork of forest, cropland, pasture, and urban areas below?  These human-modified landscapes occupy over 75% of the Earth’s land surface.  In other words, habitats available to most species are embedded within a mosaic of land that has been converted for human use.  When we alter ecosystems by reducing them in size and fragmenting them, we lose species that play important roles that maintain a working ecosystem.  One such group of species is bats.  In the tropics, bats are very abundant and have a diverse diet, including fruits, nectar, pollen, insects, frogs, fish, and blood. As a consequence, bats play an important role in seed dispersal and pollination as well as in regulating animal populations (some of which are pest species to agriculture).”

For more information, please check out her webpage, located here.

The smallest sprouts show there is really no death

green_grass_close_up_2-wallpaper-800x600

Within Walt Whitman’s poem “Song of Myself” is a section known as “A child said, what is the grass?”  The narrator has been asked the question, and, after admitting that he does not know himself, attempts to answer anyway.

“I guess it must be the flag of my disposition, out of hopeful
          green stuff woven.
 
Or I guess it is the handkerchief of the Lord,
A scented gift and remembrance designedly dropped,
Bearing the owner’s name somewhere in the corners, that we
          may see and remark and say Whose?
 
Or I guess the grass is itself a child…the produced babe 
          of the vegetation.
 
Or I guess it is a uniform heiroglyphic, 
And it means, Sprouting alike in broad zones and narrow
          zones.
Growing among black folks as among white,
Kanuck, Tuckahoe, Congressmen, Cuff, I give them the 
same, I receive them the same.
 
And now it seems to me the beautiful uncut hair of graves.”
 

It’s as if, through presenting these guesses, the narrator is working through his thoughts out loud until arriving at the final line, the assertion that grass seems to be “the uncut hair of graves.”  He is no longer guessing; and this confident decision leads into the second half of this section, in which the link between the living and the dead is examined.

But let us go back and examine the original question for ourselves: what is grass?  What is so special about it that it is cultivated and pampered for our lawns and landscaping, and yes, our graveyards?

This nearly ubiquitous plant belongs to the Gramineae family, which contains more than 9,000 species that are the dominant vegetation in many habitats, from grassland to saltmarsh, reedswamp and steppe.  In addition, grasses have adapted to thrive in rain forests, deserts, mountains, and intertidal zones.  Humans depend on grasses for an incredible number of things: for clothes, food, beer and whiskey, paper, sugar, plastics, and food for our livestock.

The grass plant itself can be annual (living only one year), biennial (two years), or perennial (comes back every year).  Most varieties are herbaceous, with a soft stem, though some are woody, possessing a permanent hard stem.  Leaves are always basal, which means they grow directly from the bottom of the stem, which is why the grass of your lawn grows back so efficiently after being cut.  See below for a diagram of the parts of a grass plant:

Diagram of grass parts.  (HowStuffWorks.com)

Diagram of grass parts. (HowStuffWorks.com)

So what’s so great about grasses?  For one thing, they’re a main part of many people’s diet worldwide.  Grasses provide our cereal crops as well as sugar, rice, corn, and feed for both wild and domestic animals (which we eat!)  Grass also cleans the air and conserves water.  Due to its sheer volume, grass traps more than 12 million tons of dust and dirt and to absorbs hundreds of pounds of sulfur dioxide each year.  This plant also traps water in its roots and prevents soil erosion; the average grassy yard can absorb more than 6,000 gallons of rainwater.  As an added bonus, the grass in your yard helps to keep you cool: according to Oregon State University, yards with grass lower the surface temperature of the ground 30-40 degrees when compared with bare soil.

So now we can think about the function of grass, and about its parts and its uses, but do these answer Whitman’s question?  After his initial musings, Whitman decides he knows what the grass is.  The poem changes at this point to be a tender meditation on the people who have gone before us, those unknown who have left only their names on a slab, or perhaps nothing at all but the uncut hair of their graves.

“What do you think has become of the young and old men?
What do you think has become of the women and
          children?
 
They are alive and well somewhere;
The smallest sprouts show there is really no death,
And if ever there was it led forward life, and does not wait
          at the end to arrest it,
And ceased the moment life appeared.
 
All goes onward and outward…and nothing collapses,
And to die is different from what any one supposed, and
          luckier.”
 

 In this poem the existence of the grass gives Whitman hope about what happens at the end of our lives.  The people we loved are alive and well somewhere, maybe not as something we would recognize, maybe transformed by the magic of biology into something else, but not gone forever.  What I take from this poem is a reminder that life goes on, that though one’s physical body may decay, nature allows beautiful life to go on all around us every day, drawing strength and sustenance from those who have gone before.  And so birds keep singing, flowers bloom, and grass sprouts anew from a fresh-dug grave.

 REFERENCES:
 

“Family Poaceae: Grass Family.”  GoBotany.NewEnglandWild.org.  Link.

Harris, Tom. 2002.   “How Grass Works.”  Howstuffworks.com.  Link.

Henderson, Desiree.  2008.  “”What is the Grass?” The roots of Walt Whitman’s cemetary meditation.”  Walt Whitman Quarterly Review 25(3): 89-107.  Link.

Whitman, Walt.  “A child said, what is the grass?”  Read it here.

Each bolt a burning river

lightning

The oaks shone
gaunt gold
on the lip
of the storm before
the wind rose, 
the shapeless mouth 
opened and began
its five-hour howl;
the lights
went out fast, branches
sidled over 
the pitch of the roof, bounced
into the yard
that grew black
within minutes, except 
for the lightning–the landscape
bulging forth like a quick
lesson in creating, then
thudding away.
 

The opening lines of Mary Oliver’s poem “Lightning” are rapid-fire and breathless as the author describes the onset of a storm.  Summer is the time of year for thunderstorms, and in New England, we have been beset by one after another for days on end.  Do you remember being a child in a thunderstorm?  Perhaps you were afraid or enchanted or awed as the sky seemed to rip apart and you could imagine the earth itself trembling.  As adults, we have learned to stifle our most primal urges, yet a thunderstorm still gives us pause.  Step onto your porch or front step on a muggy afternoon just as those distant growls begin, smell the ozone and electricity in the air, and for just a moment, you can allow that same fear or enchantment or awe to take you over.

In order for a thunderstorm to form, there must be moisture and rapidly-rising warm air.  Since both moisture and warmth are required, thunderstorms occur most often in the spring and summer.  Once a thundercloud is formed, a charge separation develops within the cloud.  The inside of a cloud contains turbulent winds, water droplets, and suspended ice particles.  Drops of water in the bottom part of the cloud are lifted by updrafts to the colder top of the cloud, where they freeze.  At the same time, downdrafts within the cloud push the frozen ice and hail down from the top of the cloud.  As the falling ice meets the rising water, electrons are stripped off, creating a charge separation in the cloud.  The lost electrons accumulate at the bottom of the cloud, giving it a negative charge, while the newly positive unfrozen droplets continue rising, giving the top of the cloud a positive charge.

Charge distribution inside  a storm cloud.  (www.nssl.noaa.gov)

Charge distribution inside a storm cloud. (www.nssl.noaa.gov)

The cloud now has an electric field associated with it, one whose strength depends on the amount of charge in the cloud.  When the negative charges at the bottom of the cloud become strong enough, they actually repel electrons on the Earth’s surface, causing  a strong positive charge, which moves up to the top of the tallest objects. When the strength of the cloud’s negative charge overcomes the insulating properties of the surrounding atmosphere, lightning results.

The strong electric field in the cloud now creates a channel called a “stepped leader” which descends from the cloud seeking a path to the ground  (this happens faster than the human eye can see).  As it nears the ground, the negative charge is met by what’s called a “streamer” of positive charge that reaches upwards from the tallest object.  When the leader meets the streamer, a powerful electrical current begins to flow, and we see what we call “lightning” as  a return stroke barrels back up to the cloud at around 60,000 miles per second.  A lightning flash can contain as many as 20 return strokes.

Inside,
as always, 
it was hard to tell
fear from excitement:
how sensual 
the lightning’s 
poured stroke!  and still,
what a fire and a risk!
 
Slow motion lightning.  Note the stepped leader prior to the strike!

Slow motion lightning. Note the stepped leader prior to the strike!

Thunder is caused by the creation of lightning.  In a fraction of a second, the lightning channel heats the surrounding air to temperatures around 18,000 degrees Fahrenheit.  The heated air expands rapidly, and causes a sound wave called thunder.  The different sounds we hear in a thunderstorm correspond to the different stages of the lightning strike: the initial tearing sound is caused by the stepped leader, the ground streamer causes the click heard at close range, and the main crash of thunder is caused by the connection between the two and the enormous amount of energy generated in a lightning “bolt”.  The reason why our perception is that thunder occurs after lightning is because light travels so much faster than sound.

So what explains the way we react to a thunderstorm?  What is it about electricity, noise, and light that results in such a visceral response in many people?  It is possible that thunderstorms are merely the most common way many people come in contact with nature on an epic scale; natural events like tornadoes and hurricanes, while terrifying, are much more rare.  There is a name for a fear of thunderstorms: astraphobia.  It occurs in adults as well as children, and is listed among the top phobias in the US.  Sufferers experience symptoms of anxiety, as well as increased interest in weather forecasts.  So in some cases, people never feel entirely safe with this weather phenomenon.  Some never escape that childhood feeling of powerlessness.

Mary Oliver’s poem swiftly and beautifully leads the reader from the rapid buildup of a storm through to its violent height.  The speaker is both terrified and excited–electrified, one might say–by the power all around.  Once again, I am amazed at how much science can be divined by the pure emotion of a natural event.  Oliver’s sensitivity to this storm allows her the ability to describe both the internal and external chaos:

As always the body
wants to hide,
wants to flow toward it–strives
to balance while
fear shouts,
excitement shouts, back
and forth–each 
bolt a burning river
tearing like escape through the dark
field of the other. 
 

REFERENCES:

“Lightning,” by Mary Oliver.  Read it here.  

“Lightning Basics.” National Severe Storms Laboratory: NOAA.  Link.

“Thunderstorm Basics.” National Severe Storms Laboratory: NOAA.  Link.

“What Causes Lightning and Thunder?” SciJinks: NASA.  Link.