I Scream, You Scream, We All Scream for Isoprene

Plants are well known for absorbing carbon dioxide from the atmosphere and replacing it with oxygen as part of the photosynthesis process. But that’s not the only thing they put into the air. Trees emit tons of a chemical known as isoprene every year, mostly during summer months. It’s surprising to learn that plants contribute to air pollution. 

An abundance of isoprene can lead to formation of greater amounts of ozone by combining with nitrogen in the form of NO and NO2. Ozone in higher levels of the atmosphere is good because it blocks harmful UV rays from the sun, but at our level it’s a major pollutant.  

The current theory is that plants produce isoprene as a method of heat resistance. Like water vapor and oxygen, it is emitted through the pores in a plant’s leaf. Not every plant produces isoprene, but the biggest producers in the US are oaks and poplars.  

Shenandoah National Park (NPS)

Isoprene is what gives the Blue Ridge Mountains their blue appearance. The chemical haze scatters blue light, which makes the mountains appear blue from a distance. It also gives the Smoky Mountains their smoky appearance. 

Great Smoky Mountains (NPS)

We learn such shocking things about nature. I had no idea before today that plants are polluting the air with volatile organic compounds, which when man-made seem to be about the worst thing under the sun. Yet here they are, also giving some of our national parks their distinguishing features and even namesakes. 

Information comes from National Center for Biotechnology Information and Department of Energy Office of Science.

Weird and Wonderful Water

Water is the stuff of life. We can't live without it, and neither can the rest of the food chain. The search for extraterrestrial life hinges on whether or not a planet or moon contains liquid water, but that assumes that any life off Earth is the same as Earth-based life. This week we'll take a look about what makes water so special and how it keeps all of us alive.

Water, the most abundant substance on Earth.
Unless air is more abundant.

Water is unique among all chemicals (yes, it's a chemical) because it is the only one found in solid, liquid, and gas states naturally on Earth. While ice and water vapor aren't basic requirements for life, they are key components of the water cycle. Water stored as snow and ice in the mountains is slowly released during the dry summers in the American west, meaning a steady flow in rivers throughout the year. Clouds made of water vapor transport precipitation over long distances. On top of that, ice and steam make modern life more convenient- think food storage and electricity generation.

Winter snow waiting for the spring melt, March 2016

Typically, solids are more dense than liquids, which in turn are more dense than gases. Water flips this around, as ice is less dense than liquid water. If you freeze a container of water, you'll notice that the ice fills more of the container than the water did. This is why your frozen pipes burst in winter. The expansion of water as it freezes is a visual of the density decreasing. Because ice is less dense than water, it floats. Because ice floats, it forms on the surface of lakes and other bodies. This allows aquatic life to survive. If water froze from the bottom up, everything would either freeze in place, or eventually be exposed on the surface.

Molecular structure of liquid water and ice (Mountain Empire CC)

Water has adhesive and cohesive properties. Water molecules stick to each other (cohesion) and other substances (adhesion). Adhesion causes capillary action. This is the movement that is responsible for plants being able to absorb water in the ground through their roots, up the stem, and to the highest leaves. Cohesion also contributes to surface tension. Water molecules on the surface are more tightly packed and can resist pressure from outside forces. This allows objects to float. Water striders can stand on the surface because of surface tension.

Water strider striding water (National Wildlife Federation)

Water has a high specific heat. Specific heat is the amount of energy needed to raise the temperature of a gram of water by one degree Celsius. Because it takes a lot of energy (1 calorie per gram) to heat water, it takes a lot of heat to boil water. Ocean life appreciates not being boiled. Water also holds onto heat it absorbs and releases it slowly, moderating Earth's temperature and making the seasonal changes gradual.

Water dissolves more substances than any other. The polar structure of the water molecule. The positive hydrogen end will attract negative ions, while the negative oxygen ends attract positive ions. Water's solvency is important for plants and animals to absorb nutrients, and for animals to flush waste from their bodies. Nonpolar substances like fats do not dissolve. That's where the saying "Oil and water don't mix" comes from. Less dense fats will float on top of water, and with some skill they can be separated.

Next time you take a drink, raise a glass in appreciation of water. Without it, your drink wouldn't be here and neither would you. This week's information comes from USGS and Mountain Empire Community College.

Hard Working Animals

Police dogs, draft horses, barn cats, and lab rats are all animals that could be considered to work a full time job. In a salute to Labor Day, here are a few wild animals that work just as hard as humans and domestic animals.

Earthworms are working hard to keep your garden healthy. Often overlooked because they remain unseen, these slimy little guys are tunneling all day, allowing air and water to move around the soil. They cycle nutrients by eating decaying plant matter, creating fertilizer that living plants can use. 

Earthworm (Christian Science Monitor)

Mound building termites built mud homes that can reach heights of 17 feet and displace a quarter ton of soil. It can take years to build, and a single heavy rainstorm can damage or destroy it. Worker termites are always on the ready to make repairs as needed. Additionally, they also farm a fungus as a digestive aid. The fungus breaks down partially digested cellulose from the wood and grass the termites had eaten. After the fungus does its thing, the termites re-ingest what the fungus broke down.

Termite mound (Journal of Experimental Biology)

Beavers are the best known engineers in the animal world. They build water tight dams out of sticks and mud. Ponds form behind the dam, and while the beavers selfishly build dams and create ponds for themselves, the important wetland habitat benefits many other species as well. Even humans benefit, as the wetlands filter water and serve as flood control.

Beaver preening

Beaver dam

While you're enjoying a long weekend, just remember the critters that work hard 365 days a year just to survive. This week's information comes from National Geographic for worms and termites.

Species of the Month

This week we're taking a break from understanding energy sources and trying to understand a species. When you think about lizards, you probably imagine them basking under the hot desert sun or on a tropical island. If that's the case, then June's Species of the Month will surprise you by showing up in some unexpected locations. Say hello to the eastern fence lizard.

Eastern fence lizard (University of Georgia)

Scientific name: Sceloporus undulatus

Kingdom: Animalia (animals)

Class: Reptilia (reptiles)

Order: Squamata (scaled reptiles)

Range: New York south to Florida, west to the Rockies

Habitat: Grasslands and forest edges

Lifespan: Unknown, thought to be four years average

Diet: Insects, some plant matter

Predators: Birds, snakes, other larger lizards, domestic dogs and cats

Conservation Status: No special protection

Other Information: The eastern fence lizard is a widespread reptile. They live under rocks and logs
where they have protection overnight. Cold-blooded, they bask in sunlight during the day to raise their
body temperatures. Normally, they bask close to where they call home. They are little guys. Adults
only grow as long as 19 centimeters. Color varies, but they are usually gray or brown. Males have a
blue patch on the throat and belly. A male will display the throat patch to attract a mate or warn other
males away from his territory. He will also do head bobs and push ups if threatened.
Fence lizard eggs grow after hatching. Mating season begins in April, with hatching taking place from
June to September. The eggs doubles in size between laying and hatching, and babies are half the size
of adults when they emerge. There is no parental care.

Male lizard showing blue throat and belly (University of California, Berkeley)

This week's information is courtesy of the Animal Diversity Web at University of Michigan. Next week
we return to our energy series with a look at wind power.

Species of the Month

Introduction: This month we celebrate the Easter season with a wild variety of one of the holiday's
decorative flowers, lilies. April's Species of the Month is the Columbia tiger lily, native to the Pacific
Northwest where I first encountered it.

My first Columbia tiger lily sighting

 Scientific name: Lilium columbianum

Kingdom: Plantae (plants)

Class: Liliopsida

Order: Liliales (lilies)

Columbia tiger lily with neighbors in its community

Range: California to British Columbia, northern Idaho and northwestern Montana

Habitat: Open woods or fields with well-drained soils and partial shade

Diet: Sunlight and water

Conservation Status: No special protection

Like the others before, this lily is growing on a mountainside

Other Information: Bright and cheery flowers adorn this lily, which can grow to six feet tall with a
dozen blossoms, although it is typically only three feet tall. The stems droop so the flower faces
downward. Depending on elevation, flowers bloom from June to September. I discovered the tiger lily
in the Cascades, in a forest clearing along the trail. For a good portion of the year, those few plants I
saw are buried under deep snow. Alternate names include Columbia lily, Oregon lily, and tiger lily. I
prefer not to use "tiger lily", as I associate that name with the larger, decorative plant.
This week's information comes from USDA and Lady Bird Johnson Wildflower Center. All photos are
my own.

Herring Spawning

One of the great spectacles in North American wildlife watching is the Pacific herring spawning. It happens every year in late winter and early spring. Not only does the event produce the next generation of an important fish species, it also sustains the current generation of many other animals.

Pacific herring form an important strand in the food web. They are classified as forage fish, meaning they serve as meals for larger fish like salmon. As we'll see a little later, herrings feed the larger community beyond just the salmon.

Herring spawning turns the sea white (Prince William Sound Conservation Center) 

Herring move to shallower seas during spring, which happens to be right around the same time hungry humpback whales arrive from the tropics. The herring are looking for eelgrass or kelp beds for their sticky eggs to attach to. After the females lay their eggs over the vegetation, the males swim over and release their milt to fertilize the eggs.

Before reaching the spawning beds, the herring must navigate a maze of predators: sea lions, sea birds like cormorants and gulls, bald eagles, and those hungry, hungry humpbacks. Once the work is done, the eggs aren't safe and the smorgasbord continues as diving ducks pick them off. About two weeks later, the remaining eggs hatch and the herring larvae are carried by the tide and are subject to predation by fish of all shapes and sizes.

Herring eggs attached to kelp (US Geologic Survey)

With all that eating going on, it's a wonder any herring survive to adulthood. Females typically lay 20,000 eggs a year, and if she lives a long life, she'll do this three times. Multiply her by a million of her closest friends, and you have about 20 billion eggs. If only 1% hatch, that's 200 million baby herring.

Sea lions await their feast (Tillamook Coast)

In a good year, spawning herring will color the sea white. However, the spawning isn't nearly as good as it used to be. Overfishing is one reason, but loss of habitat (spawning and feeding areas) and pollution are also big contributors.
This week's information comes from Wayne Hoffman, Ph.D. and Washington Department of Natural Resources.
nm1: Prince William Sound Conservation Center https://pwssc.org/herring-spawn/
nm2: USGS https://www.usgs.gov/media/images/pacific-herring-eggs-macrophytes
nm3: Wayne Hoffman https://tillamookcoast.com/blog/spawning-of-pacific-herring/

Amazing Okavango

Ever hear of the Okavango River in Africa? You probably haven't. It's a rare river that flows into an inland delta rather than the ocean. During the winter, it floods the glassland and creates a seasonal wetland that attracts wildlife from all over Africa in one of the world's greatest migrations. It is an amazing oasis in the Kalahari Desert.

Flooded Okavango (Natural World Safaris)

The annual flood occurs at the height of Botswana's dry season, so it offers welcome relief to the plants and animals in the area, in addition to welcoming migratory animals of all shapes and sizes. The abundance of water boosts the growth of plants, drawing in herbivores. The herbivores attract large predators.

Elephants (Royist)

Safari cruise through the grasslands (National Geographic)

Among the many different animals who take advantage of the situation are elephants, lions, cheetahs, zebras, rhinos, 89 fish species, and 24 globally threatened birds. Not only is the Okavango key to survival of individual animals, it is crucial habitat for entire species.

Lion and buffalo (National Geographic)

A safari in the Okavango is like watching "The Lion King" live and in person. This weeks information comes from UNESCO World Heritage.

Glossary of Terms

Here at Nature minute, we use a lot of big words, or even just smaller words you've probably never heard before. It's a fine line between going over your head with technical terms and dumbing it down too much. In the interest of walking that line, here are some of the words you might hear thrown around the office or in the field.

Alluvium- eroded sediments, deposited on land by water. Areas are sometimes referred to as "alluvial plains"; these are where the soil is made up of mostly alluvium.
Benthic- the bottom of a body of water. A river bed and the sea floor are benthic zones, or benthos. Benthic also refers to the organisms living in the benthos.

These insect larvae are benthic creatures

Brumation- a state of lowered metabolic activity in cold-blooded animals; it is similar to hibernation.
Crepuscular- active around dawn and dusk. Deer are crepuscular mammals.

Deer being crepuscular in my back yard, circa 2015

Epiphyte- plants which grow on other plants, but are not parasitic. In the Pacific Northwest, ferns often grown in trees.

Epiphytic ferns

Ephemeral- seasonal. During the spring melt, ephemeral streams and waterfalls form in the mountains.

Ephemeral waterfall cascading down a hillside

Fossorial- digging species which live mainly underground. Moles and badgers are fossorial mammals.
Hadal- the deepest oceanic zone. Deep sea trenches are the hadal zone.
Littoral- the nearshore zone of a body of water, from the high tide line to the shoreline.

This horseshoe crab is in the littoral zone

Torpor- a state of lowered metabolic activity and body temperature in warm-blooded animals. Like brumation, it is similar to hibernation.
Transpiration- water exhalation by a plant. Water is lost as vapor through pores in the leaves.
Ungulate- mammals with a hoof. They come in 2 orders: Artiodactyla, which have an even number of toes, and Perissodactyla, which have an odd number of toes. Those crepuscular deer are ungulates.

Species of the Month

This month we are looking at one of the largest mammals in North America, the moose. Since they are
found in the northern areas, I decided the dead of winter is a great time to profile this great beast. If you
are ever lucky enough to see one, they are best viewed from a distance. Size may be deceiving. They
move quickly and won't hesitate to mess you up!

Moose in Alaska (NPS)

Scientific name: Alces alces

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Artiodactyla (even-toed mammals)

Range: Northern North America

Habitat: Forested areas near freshwater

Lifespan: 8-12 years on average

Moose shedding his antler velvet (NPS)

Diet: Twigs, bark, and roots of trees- especially aspen, willow, and conifers; aquatic plants during
summer months

Predators: Wolves, bears (black and grizzly), humans

Conservation Status: Species of Special Concern in Michigan; no special protection in other areas

Other Information: The moose is so cool! Or at least it strives to be. Body size, coupled with an
inability to sweat, means they have to seek shade and water in or to avoid overheating during summer
months. Just how big is a moose? They can grow to be 7 feet tall at the shoulder! Males grow antlers
for mating season and shed them afterwards. Those antlers, largest in the animal world, can span 6 feet.
Calf mortality is high- 50%. Due to their size, calves are more likely than adults to suffer predation by
wolves or bears. Adults are armed with sharp hooves, in addition to those huge antlers on males. Moose
disease is a fatal brainworm parasitic infection, also seen in deer. Ticks also present a problem. They
can weaken a moose to the point of death from blood loss.

Mama moose with calf in Michigan (NPS)

Our moose information comes from University of Michigan's Animal Diversity Web.

Species of the Month

With Thanksgiving just a week away, once again we turn our attention to the dinner plate. In years past, November's Species of the Month has featured the wild turkey, venison, and clams that were likely present at the first Thanksgiving. This year, we look at a staple of the modern celebration, the North American cranberry.

Whole berry cranberries (UWLC)

Scientific name: Vaccinium macrocarpon

Kingdom: Plantae (plants)

Class: Magnoliopsida (dicots)
Order: Ericales (heath)

Cranberries on the shrub (UWLC)

Range: US west coast, northeast US and Great Lakes areas
Habitat: Bogs with acidic soil
Diet: Water and sunlight
Predators: Bears, rodents, birds, deer, humans
Conservation Status: Listed as endangered in Illinois and threatened in Tennessee

Cranberry bog

Other facts: Cranberries grow in freshwater peat bogs. They are grown commercially for use in food products. The best use is the canned jellied cranberry. Cranberry plants are useful as a food source for animals. Birds, bear, and rodents eat the berry, while deer browse the shrub. Birds and rodents also use the stems for nesting material. Birds may also build a nest in the shrub. Cranberries also form a symbiotic relationship with fungi, giving up sugar in exchange for access to soil nutrients. Cranberries can survive being submerged for long periods, and even being kept on ice over the winter.

Cranberry flower (Cape Cod Cranberry Growers)

This week's information comes from Cape Cod Cranberry Growers Association, USDA PLANTS, and University of Wisconsin- La Crosse. Pictures, except the flower, are also from University of Wisconsin- La Crosse.

Changing Leaves

Fall is in full swing. The sun keeps the air warm, but it's chilly in the shade. Honking geese fly overhead and crickets chirp throughout the lengthening nights. Dried leaves swirls about in the breeze, while those still in the trees for a riot of color. What is going on inside the tree that causes the color change?
Trees are getting ready for a long winter's nap. Like animals going into hibernation, everything is slowing down. Trees have been gorging themselves on sunlight all summer, and now their metabolism is slowing down. The chlorophyll is breaking down and water uptake is stopping. Chlorophyll absorbs all wavelengths of light except green, which is reflected back to us. Without chlorophyll, we see other chemicals in the leaf.

A yellow sugar maple catches the late morning sun

The yellow leaf of a sugar maple

Xanthophyll colors the leaves of aspens, birches, and beeches a bright yellow. It's also found in corn.  Red and purple in red maples and scarlet oaks comes from anthocyanin, which is produced when the chlorophyll stops and the leaf metabolizes extra sugars. Carotene, the same as what you find in a carrot, gives trees like sugar maple and sassafras their orange leaves. Orange can also come from a leaf that is showing both xanthophyll and anthocyanin. Brown, such as in oaks, comes from tannins. Carotene and Xanthophyll are present all year in the leaves, but are overshadowed by chlorophyll.

Another sugar maple, this one decked out in red

This red sugar maple leaf fell of a Canadian flag

The brilliance of each color, as well as the amount of colors relative to each other, are dependent on the weather. If fall is sunny and dry, trees will produce more anthocyanin. Trees will be a more brilliant red. Other years, trees won't produce as much or even none at all and nearly all leaves will change to yellow.
But of course, each tree is an individual so it may change well before its neighbor or have different or more vibrant colors, even among the same species. I've seen red maples that look like traffic lights with red, yellow, and green leaves on the same tree. I've even seen multi-colored leaves.

Brown oak leaf, rich in tannin

Yet another sugar maple, this time in orange

Get out there and enjoy some biochemistry in action before it's too late! The leaves have been great this year, peaking in my area this week and next. Up north you may be past peak, and down south it's on its way! This week's information comes from SUNY College of Environmental Science and Forestry and Montana Natural History Center.

Yellow and brown hickories and oaks basking in late
afternoon sunshine

Species of the Month

With Halloween right around the corner, October's Species of the Month is another creepy crawly. You might be afraid of spiders or bats, but no one wants to see a rat in the house. This month we profile the ubiquitous black rat (AKA house rat, AKA roof rat, AKA ship rat), destroyer of crops, chewer of things, and spreader of plague. 

Halloween rats from Pintrest

Scientific name: Rattus rattus
Kingdom: Animalia (animals)

Class:  Mammalia (mammals)
Order: Rodentia (rodents) 

Range: Worldwide; native to India and Southeast Asia
Habitat: Almost anywhere
Lifespan: Average 1 year, up to 4 years

Black rat (Inventaire National du Patrimoine Naturel)

Diet: Omnivorous, but mainly plant-based (fruits, grains, seeds)
Predators: House cats, birds of prey, foxes, coyotes
Conservation Status: No special protection
Other facts: The black rat was spread around the world by travelers. They are also called ship rats because if their affinity for sailing to new homes on distant shores. The moniker roof rat comes from their climbing skills. They are an invasive pest everywhere outside of their native range, ruining food stores by soiling what they don't consume. They were a disease vector during the plague outbreaks of Medieval Europe, carrying fleas that hosted the virus. While plague is not as serious a threat as it was in the Dark Ages, the fleas on a rat can still spread other diseases to humans and livestock. A similar species, the Norway rat, is just as widespread and will kill the smaller black rat. Despite the headaches caused by both rats, they are important links in the food chain now that they've become established. Hawks, owls, coyotes, and foxes are among their main predators.

Black rat (Australian Environmental Pest Managers Association)

This month's information comes from the University of Michigan's Animal Diversity Web once again.

nm1: 
nm2: https://www.aepma.com.au/PestDetail/96/Black%20Rat

Getaway Islands

Summer is here and for many people it's the perfect time to relax at the beach. If you're at an East Coast beach, odds are you're on a barrier island. The Atlantic barrier islands extend from Canada to Florida, then up Florida's Gulf Coast and all the way around to Mexico. Prior to development, many of these islands came and went at the whims of the tides and storms. Now that we've built homes and resorts on them, there is a vested interest to make them more permanent by using jetties to block the outflow of sand and beach replenishment to restore what's been lost. Let's take a look at the natural history of where you built that sand castle.

Grassy dune in New Jersey

Barrier islands, if left to nature, live and die by the tides. Ocean currents carry sand away from the islands. The sand either moves out to the sea floor, where it can be brought back to the island by currents, or it is carried to another part of the island or to a different island. Strong storms can accelerate the process, wiping islands off the map or opening up a new inlet to the back bay.

Hurricane Irene cut these inlets across Hatteras Island (NOAA) 

Barrier islands can move toward the mainland as wind blows sand over the dunes to the bay side. The marshes fill in with sand and build up new dunes, while ocean moves to where the dunes originally were and new marshes form in the bay on the edge of the old marshes.

Salt marsh at Assateague Island (NPS)

The islands are important because they are barriers protecting the mainland from such storms. A few weeks ago we looked at hurricanes on this blog. Barrier islands absorb the brunt of the storm surge that comes in ahead of the hurricane. Developed barrier islands still absorb the storm surge, but not as well as undeveloped islands from times past. Impermeable surfaces like roads and parking are terrible at absorbing water, while sand drains quickly. If the dunes have been removed from an island, the storm surge rushes right over top with nothing but buildings to slow it down.
Barrier islands are also important as habitat for critters other than summer vacationers. On an undeveloped island, different plants and animals that can tolerate different amounts of salt water and exposure to the air make their homes in different zones. Clams live beneath the sandy shore, while birds that prey on them scurry above. Grasses hold the dunes in place, and at the highest points of the island you can find trees and shrubs where songbirds and mammals live. Brackish marshes on the other side of the dunes host crabs and serve as a nursery where fish can eat and grow before venturing into the open sea. Wading shorebirds take advantage of this bounty. Beyond the marsh is the back bay and the mainland.

Ghost crab (NPS)

Sandpiper feeding frenzy

The US has more barrier islands than any other country in the world. Best known are New York's Fire Island, Texas's South Padre Island, the Outer Banks of North Carolina, and the Jersey Shore. If you spend a summer weekend at the beach, be sure to check out the wild side of things.
This week's information comes from Science News for Students.