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.

Pros and Cons of Hydroelectric

Hydroelectric power generates the most electricity of all renewable energy sources in the US, about
7% of the total production. It is a truly renewable source as the same water can flow through a series of dams on a single river, and it is renewable. It is also “clean”, producing no carbon emissions outside of those during the dam building process. 

Water held back by a dam goes through an intake pipe and turns turbines as it passes through the dam.
Faster flowing water will produce more power. Hydroelectric power is about 90% efficient, making it a
great source of power. Due to controls at the dam, the flow of water can be adjusted to meet peak
demands much more quickly than at a nuclear or coal-fired plant. Some dams are equipped with a
pump and can pump water to a higher level during times of low energy usage. The water is then
released back through the dam at peak times to generate additional power.

Not all dams are generating stations, but hydroelectric dams often serve other purposes such as flood
control, irrigation, drinking water supply, and recreation. Because the water is naturally occurring and
free, hydroelectric power is among the cheapest on the market, less than a penny per kilowatt hour on
average. An electric utility can earn additional income through recreational fees, keeping utility rates
low.

Hydroelectric dam in Arizona (USGS)

Although hydroelectric power is “clean”, it is not completely “green”. Like the fossil fuels, it also has
negative environmental impacts. Dams affect fish migration, hydrology, and sediment and nutrient
movement. Flooding a reservoir also causes terrestrial habitat loss, which is traded for aquatic habitat.

Fish ladders can be built to aid anadromous fish in passing around a dam. These fish hatch in
freshwater, live as adults at sea, and return to their native streams to spawn. The journey through
natural aquatic habit frequently involves jumping over small waterfalls, which fish ladders mimic.
Different species of fish move at different speeds and therefore have different needs. Fish ladders come
in many different designs, and some even look like a natural stream rather than a flooded staircase.
Intake screens covering the intake pipes can successfully keep most fish from getting sucked into the
turbines, which can kill them.

Fish ladder (Army Corps of Engineers)

Terrestrial habitat is lost at the expense of aquatic habitat gain. However, the reservoir behind the dam
is of lower quality than a natural lake and alters downstream hydrology. Reservoir water stagnates
since there is no outlet and sediments and nutrients from upstream collect behind the dam rather than
enriching downstream areas. Downstream ecosystems can also suffer if not enough water is released
from the dam.

Sediment deposits after a dam removal in Washington (NPS)

This week's information comes from US Bureau of Reclamation, Michigan DNR, and
Union of Concerned Scientists.

Deciduous Decisions

In the plant world there are two types of trees: deciduous and evergreen. Deciduous trees give us spectacular displays of fall color before shedding their leaves. Evergreens provide a shadow of summer with a splash of green during the bleak winter days. Both types of trees use the leaves (broad leaf or needle leaf) for photosynthesis, but obviously the deciduous tree evolved to opt out of photosynthesis during winter while the evergreens evolved to work a longer season. Which tree has the competitive advantage until the spring greenup?

Life in the wild is all about two things: making babies and being energy efficient. Depending on the environment and situation, being deciduous or evergreen offers a competitive advantage by saving energy, but of course it also comes at a price.

Deciduous trees typically live in areas with temperature fluctuations. Here in the northeast, we have a nice mix of deciduous trees: maples, oaks, hickories, poplars, and more. We also have four distinct seasons. Winters can be snowy, and for a tree that spreads it branches quite a distance from its trunk, not having leaves to catch a heavy snowfall could be the difference between losing limbs or not. Evergreens compensate for snowfall by having a conical shape and shorter branches, with the longest at the bottom. The branch structure allows snow to fall to the next level of branches relatively quickly.

Summer deciduous

While the loss of leaves saves branches, it costs the tree energy. A tree must have enough energy stored up for next spring’s new leaves by fall. Because photosynthesis uses energy (much like chewing and digesting your food burns calories), deciduous trees evolved to shed leaves when there is less sunlight, not enough to be worth the energy expense to generate some more energy. While the deciduous trees are standing idly through the winter, evergreens take advantage of their ever green leaves (either needles or broad leaves in the tropics) and photosynthesize for a longer season or year-round in the tropics. They gain a little more energy that way, and we’ll see why next.

Late fall deciduous

Those expendable deciduous leaves are fairly flimsy compared to a pine needle or palm frond, which are built to last. Less energy is required to build a full set of maple leaves than pine needles. More of the maple leaf is dedicated to photosynthesis than a pine needle, which needs more compounds for structure and defense. Unit for unit, a maple leaf generates more energy than a pine needle. Evergreens, conifers especially, use that conical structure to capture more sunlight to maximize energy production.

Summer evergreen conifers

Deciduous trees thrive in nutrient-rich soil. If there are plenty of nutrients to absorb, they can afford to shed leaves. They often draw remaining nutrients from the leaves back into the trunk before shedding leaves. They even contribute to the nutrient cycle with their fallen decaying leaves. Evergreens have adapted to nutrient-poor soil. They keep their leaves because of a lack of available nutrients. If you look at how green and full of life the tropical rainforests and dense forests of the Pacific Northwest are, you may be shocked at how poor the soil actually is. The nutrients are usually absorbed right out of the dead material into the upper layer of soil and into the living trees.

Winter evergreen conifers

The different leaf styles also lead to different strategies for water conservation. When stressed due to dry conditions, deciduous trees will shed their leaves early to stop water loss. During photosynthesis, water is drawn from the roots to the leaves to make it happen, and the trees exhale water vapor. Evergreens keep their leaves, but they have a waxy cuticle on them that helps prevent water loss.

Hopefully you have a better understanding of why trees do what they do. With fall here and winter on the way I think we can appreciate both leaf styles for the splashes of color they give us. How is the leaf situation in your neighborhood?
This week's information comes from an article by Frances C Smith in the journal Maine Naturalist. 
Frances C Smith: Smith, F. (1993). Evergreen vs. Deciduous Woody Plants: Which Wins Where. Maine Naturalist, 1(4), 205-212. doi:10.2307/3858181 

Dead Zones

This week we’re taking a look at a problematic summer tradition: hypoxic dead zones. These are marine or aquatic areas that don’t have enough oxygen to support life. The most famous is probably the dead zone in the Gulf of Mexico. Let’s look at dead zones, how they form, and what you can do to help prevent them.

The most common cause of dead zones is excessive nutrient runoff. Nutrients in this case are nitrogen and phosphorus, nutrients from plants. The main source of this nutrient runoff is agriculture, but it can also come from detergents, animal waste, and untreated sewage.

Gulf of Mexico dead zone (Digital Journal)

The nutrient overload leads to a sudden population boom in the local algae community. It seems paradoxical that algae, which produces oxygen, leads to an area without oxygen. First, when a large mat of algae covers the water’s surface it prevents oxygenation at the water/air interface. Then, when the algae dies and decomposes, that is where the oxygen disappears to. Mobile critters like fish can move to more oxygenated areas to survive, but something that can’t move or is very slow like a starfish or sea urchin will suffocate unless the situation clears up.

How a dead zone forms (Gulf Hypoxia)

Sometimes the algae bloom is of a type that produces toxins. Sometimes the toxins cause fish kills. Shellfish can absorb the toxins through filter feeding and pass them on to predators and people. Algae toxins can even threaten public drinking water.

A closer look at an algae bloom (NOAA)

How can you help? Trying to stop non-point pollution seems hopeless, but if everyone ups their game a little bit it adds up and makes a difference. Simple steps you can take at home include limiting the amount of fertilizer you use for your lawn and garden, cleaning up after your pup, and washing your car in the grass rather than the driveway or street. Reducing fertilizer use reduces the amount of excess nitrogen and phosphorus washing into the storm drain and out to sea. If you’re already doing that, buy organic produce which doesn’t use any fertilizer or pesticide. Picking up your dog poop keeps the nitrogen and phosphorus from that source out of the system as well. Washing your car in the yard lets the phosphorus in the detergent soak into the yard rather than washing into the storm drain. Every little bit helps.

This week's information comes from the EPA.