Friday, February 24, 2017

The Seasonal Metamorphosis of a Pond

Imagine you are looking at a pond. What do you see? Many would say water, plants, fish, maybe a few frogs.  But there is much more to a pond ecosystem than just meets the eye.  In the spring, a pond is an area teeming with life, while during the winter, everything seems to go still.  So what exactly is happening just below the surface?

During the winter, it may seem like everything in a pond has been put on hold.  This is partially true, as activity is slowed greatly during this season.  Turtles and frogs have retreated into the cozy warmth of the mud.  Insects are no longer skimming across the surface.  The metabolism of organisms in the pond as well as the amount of photosynthesis that is taking place is greatly decreased during the winter.  This is an important adaptation as both food and sunlight are in short supply.  In areas where ice is able to form on a pond, several changes occur. Since ice is less dense than liquid water, ice will form at the top of the pond and will even provide insulation for the water underneath.  Just below this icy layer, life still exists, but in a much more lulled state.  The ice prevents a lot of sunlight from reaching the bottom, and with shorter daylight hours, very little photosynthesis takes place.  The layer of ice also prevents normal gas exchange within a pond from occurring. Without access to the atmosphere, there will be much less dissolved oxygen.  Luckily, colder water holds more oxygen, and pond animals are adapted to use much less oxygen in the winter than they would in the summer.  This is what makes a winter pond seem so tranquil, as the pond organisms are trying to use as little energy as possible.  Although everything is still during the winter, the pond organisms are getting ready for a season that is anything but still. 

As the air temperature warms and the ice cracks and thaws the pond seems to spring to life again.  During this season, the pond is open to normal gas exchange processes and the dissolved oxygen content begins to increase.  The pond is also opened up to more sunlight, which leads to a cascade of life processes beginning again.  The first sign of the affects of spring in the pond is that the pond will become murky.  This is due to bacterial and phytoplankton blooms.  Then the decomposers of the pond will begin breaking down dead matter and releasing important nutrients into the body of water. With the presence of sunlight, ammonia, and carbon dioxide now readily available, algae will begin growing.  This is an important food source for herbivorous micro- and macro-organisms.  Amphibians are drawn back to the water source from which they are born, and soon the calls of frogs and toads will ring out from the edges of the pond as they begin their reproduction cycle.  The fish and aquatic invertebrates will also come to life after their long resting season.  Spring is the season of new life and action in a pond.
Photo credit: Macroscopic Solutions
During the summer, the pond becomes calm again.  Turtles bask lazily in the sun, as fish catch insects on the surface of the water.  Frogs and salamanders are entering their adult stages and leaving the water, as aquatic invertebrates go through metamorphosis and sprout wings.  Most of the oxygen that is now in the water is provided by the abundant plant life soaking in the sun.  Insect catching birds soar across the water in search of their next meal.  During hot summer days, water temperature may increase greatly.  Fish will retreat to the depths of the pond in search of cooler temperatures.  Amphibians rely on bushes and other plant coverage on the edge of ponds for shade from the sun.  The summer provides a warm resting period for the pond after a long season of activity and reproduction.

This is a season of change, not just in the trees, but in the pond as well.  It is a time of transition, where the pond ecosystem is getting ready for the still, cold winter.  As the pond's temperature decreases, it will absorb more oxygen.  This is a cue for the organisms in the pond to use less oxygen and energy.  Fish will produce less ammonia so that it doesn't get trapped under the ice during the winter.  In place of the summer birds, geese and ducks will migrate in.  The berries that were produced in the end of summer will be picked clean by small mammals preparing for winter.  This is a season of preparation, so that each species is able to survive a harsh winter.

A pond is constantly going through changes, as life circulates in and out of the ecosystem.  Everything that lives there depends on the water.  Each small change in the water means a change for every life form living there.  The pond ecosystem is an exciting and fascinating example of the ebb and flow of life throughout the seasons.

Tuesday, February 21, 2017

Crystal Award Winners at Sierra Outdoor School

The Crystal Award, is Clovis Unified School District's highest employee recognition award, has landed at the Sierra Outdoor School!

The Crystal Award is a prestigious award that honors employees of Clovis Unified School District for their above-and-beyond work.  This peer nominated award recognizes those making a significant difference in the lives of Clovis Unified students.

Superintendent Dr. Janet Young sums up the spirit of the Crystal Award as, “The Crystal Awards celebrates these winners who are true examples of the values and character that make Clovis Unified so special. Their passion, innovation, dedication and dynamic work ethic help our students reach their full potential in mind, body and spirit.”

While CUSD has almost 6,000 employees, only 32 employees were selected as 2016 Crystal Award recipients.  It is an honor to have two Sierra Outdoor School employees be selected for the Crystal Award in the same year:  Sharon Bush and Mike Olenchalk.
Sharon Bush and Mike Olenchalk hearing the news that they were both selected as Crystal Award  Recipients. 
Sharon is the school’s baker and a breakfast cook. If you ever had any of the delicious cookies at lunch or dinner, then you have tasted her handiwork. No matter how early it is in the morning, what the weather was like driving here, or how many students are eagerly awaiting breakfast, Sharon always has a smile on her face and something positive to share with our visitors. A graduate of Clovis High, Sharon has been at Sierra Outdoor School since 2002.

Mike Olenchalk has been part of Clovis Unified since 1985 and embodies Clovis values. After teaching high school biology for many years, he became Sierra Outdoor School's Director in 2001. He may not have realized when he took this position that he wouldn't only be directing this school, but also overseeing the renovation of almost every building on campus, navigating an economic downturn, getting legislation passed in Sacramento, plowing roads at all hours of the day and night, assisting with plumbing emergencies, and leading mountain bike classes, and he has done an outstanding job of it!

The SOS staff would like to congratulate Sharon and Mike for being recognized and honored with this special award. We thank you both for your hard work and dedication to Clovis Unified School District and Sierra Outdoor School. We are so proud to have you as part of the SOS team.

Steve France presenting the Crystal Award to Mike Olenchalk and Sharon Bush.  All winners will be honored at a special presentation in Clovis.   In addition each winner receives a monetary award to use at their school site.

Wednesday, February 1, 2017

Wait, do bears really hibernate?! Waking up to the truth about winter's sleep

Imagine yourself going for a hike through the vast Emigrant Wilderness in the Sierra Nevada Mountains. You stop to look out over a field covered in the first light snowfall of the year. You’re captured by its beauty. One snowflake falls on your nose, then two, then more cover your hair. It’s mid-November. A crisp breeze rolls over the field and makes you shiver. What would you do next? Being a smart hiker, you probably brought a warm cozy jacket. Maybe it’s fleece, and if you’re experienced in the wilderness, it’s probably waterproof.
Now imagine yourself on this same field of freshly fallen snow, but instead of two feet in wool socks and hiking boots, you now have four large paws covered in dark brown fur. Your five claws are sharp from climbing trees to reach nuts, berries, and seeds. Your fur has thickened in the recent months. The snow is falling gently, covering your snout and ears. That same crisp breeze rolls across the field… but you hardly feel it. That 350 pounds you put on in the recent months is really paying off now. And it will continue to pay off in the months to come. You have been eating up to 20,000 calories per day, which is like eating 40 Big Mac burgers per day! Foraging takes up 20-23 hours per day, leaving you only 1-4 hours to sleep per night. But don’t worry, you’ll have plenty of time to sleep later.[1,6] Some wildlife biologists call this foraging the “fall shuffle” as bears will search up to 60 miles away from their home for food to prepare for winter.[6] Now, you turn away from the field, and journey back to your winter den. You find your warm waterproof cave nestled under three large boulders. You enter and curl up on the ground. Every part of your body begins to slow down. Your heart beat, your breathing, and your body temperature drop lower and lower. You fall into a deep slumber that may last for days or weeks at a time. You won’t eat, drink, urinate, or make scat. Instead, your body is adapted to keep your bones and muscles strong by cycling calcium, and using nitrogen from fat metabolism to build protein for muscle mass.[2,7]

But here’s the question: Are you really “hibernating” or are you only sleeping through something we call “torpor”? The answer to this question will show you that the world of winter sleeping is a far more complex one than you may have thought.

Hibernation is a process where an animal falls into a deep sleep that lasts several days to several months. They may only take one or two breaths per minute. In small mammals like the ground squirrel and hedgehog, body temperature will drop to almost freezing – temperatures around 37 degrees Fahrenheit (F). Heart rate slows in bats from 600 beats per minute (bpm) to 20 bpm.

Left: Two chipmunks snuggle for warmth during a fall nap.
Right: A bat sleeps in a torpid state in the basement of an abandoned house.
Chipmunk photo credit: Pinterest. Accessed 2/1/17.

Bat photo credit: Five Valleys Ecology. “Bats: Bat Biology.” Accessed 2/1/17.

Torpor is a state that many animals, like the chipmunk, will enter on cold winter days. It’s similar to hibernation in some ways. Breathing slows, body temperature lowers, and heart rate goes down. Unlike hibernation, however, animals in torpor will usually sleep for only a day or two, then wake up to forage for food. In torpor, body temperature only lowers a few degrees.[1] Animals that enter torpor may do so simply to take a break from the cold winter day, saving energy for hunting later.

An Alaskan bear showing off some serious snoring during hibernation.

*If you’re using CUSD internet, here’s the sciencemag article where you can watch the video: - scroll halfway down the page.

Bears land right on the line between hibernation and torpor. Their body temperature lowers at most 12 degrees, staying above 88 degrees F. [2] This is not nearly as low as smaller mammalian hibernators. Bears often wake up several times during hibernation, too, which looks like torpor. Thus, if we only look at temperature drop and length of sleep cycles, bears may not be considered “true hibernators.” In fact, before the 1980s, some people shunned the term “hibernator” to describe bears, preferring the term torpor to describe their winter sleep.[4] It wasn’t until 1981 that biologists redefined hibernation in mammals as “a specialized, seasonal reduction in metabolism concurrent with scarce food and cold weather.”[4,5] Once they realized that there was a whole lot more to hibernating than just body temperature, the definition of hibernation extended to many animals, not just those whose temperature dropped to near freezing. Today, many physiologists say bears hibernate, while some prefer calling it extended torpor.[4] In the end, it’s all a matter of how you define hibernation. Torpor usually refers to shorter sleeps, while hibernation lasts longer.

By the end of this we hope you have gained at least two things:
1)   An appreciation for the complex world of winter sleep.
2)   At least one new fancy word to show off to your friends.

Lastly, here’s a cool table that shows you the winter survival strategies of many different animal species from the Sierra Nevada Mountains. Bugs, amphibians, mammals, and more:

For more on black bears, hibernation, and what they do to prepare for winter, visit these sites and any of the references listed below:

5.    Watts, P. D., N. A. Oritsland, C. Jonkel, and K. Ronald. 1981. Mammalian hibernation and the oxygen consumption of a denning black bear. Comparative Biochemistry and Physiology, A. Comparative Physiology, 69:121-123.