The Sage of the West

Let’s head back into the heat again this week and explore another warm, dry ecosystem. Sage scrubland is semi-arid and unless you live there, you probably aren’t familiar with it. Like the desert, it can appear to be devoid of life unless you know where to look.

Sage scrubland in Idaho (USFS)

The ecosystem is defined by sagebrush being the dominant plant species with hot, dry summers and cold winters. Most precipitation is winter snow and spring rain. Sage scrubland ecosystems are found in the Intermountain West and California’s coastal chaparral ecosystem.

Many animals call the sage scrubland home. Small mammals and reptiles are well represented in the list of fauna. The endangered black-footed ferret is among them, and it was in Wyoming’s sage scrubland that a colony was discovered after the species had been given up as extinct. They were all captured and put into a captive breeding program which has seeded recovery efforts throughout the West. Larger mammals include elk, mule deer, and pronghorn.

Black-footed ferret (USFWS)

Birds of prey are common inhabitants of this ecosystem. The sage grouse (of course) also calls this area home. This threatened bird relies heavily on the sagebrush for its survival. Not only is sage a staple if its diet, it also uses the plant for cover.

Male sage grouse (USFWS)

Sagebrush, the dominant plant in this ecosystem, provides sustenance for species other than the sage grouse. When the deer and the antelope aren’t playing, they can be found nibbling on sage brush. It is especially important during the winter when other lower plants are buried under snow. 

Like so many other habitats in the world, sage scrubland is in danger. Development destroys or fragments the habitat. Oil and gas drilling scare away resident critters and disrupt migrations. Invasive plants crowd out the natives and create a vegetation density conducive to fire. While sagebrush can withstand low intensity fire, hotter fires fueled by invasive cheatgrass destroys it. Agriculture converts sage land to crop land.

Sagebrush in Oregon

There is hope, of course. Most sage scrubland is in sparsely populated areas so it is disappearing at a slower pace than other areas. Agriculture, which can be destructive to this ecosystem, can also be a conservation partner. It makes a great low-maintenance rangeland if done sustainably.

Sage scrubland is an important, but unheard of ecosystem. Most people think of the Intermountain West as just drive-through or fly-over country. Eastern Washington is a million shades of brown from 30,000 feet. But while driving across eastern Oregon, southern Idaho, and northern Wyoming I was quite taken with the beauty and solitude of the seemingly endless sea of sage.

This week's information comes from US Fish and Wildlife Service, Oregon Department of Fish and Wildlife, and Wyoming Game and Fish Department.

The Good Old Days

This week’s adventure takes a peek at the past. Earth was a vastly different place in the good old days. Dinosaurs ruled and everything was just a bigger, sabre-toothed version of the critters we have today. OK, maybe not the bigger, pointier critters. But scientists can tell us a lot about the way things used to be by looking at the fossil record.

Fossils are like prehistoric pictures. They form when dead organic material is slowly replaced by mineral material. Not everything that ever died was destined to become a fossil; only in certain conditions could the transition take place. Being in a situation without oxygen would’ve helped your cause if you were hoping to fossilize. Oxygen is a requirement for decomposition. If you’re decomposing, you won’t leave behind anything to fossilize. 

Little worm fossils imprinted on a rock

Usually when you think of fossils you think of huge dinosaur bones. There are other types of fossils too. Footprints in dried mud that later turned to stone can be found in Alaska and Africa.

Dinosaur footprint found at Denali National Park (NPS)

Imprints of shells in rock are mountains that used to be sea floor. One wound up in my back yard in Pennsylvania. One day a dead plant was buried in between layers of sediment that hardened into rock. Years later, I squeezed that rock and found black images of that plant inside the rock. Whole trees can be fossilized into petrified wood. Ancient insects trapped in tree sap that hardened into amber are also fossils.

A rock full of shells from my back yard

Plant fossils inside a piece of sedimentary rock

If you want to find some fossils, you don’t need to be a paleontologist or geologist. All it takes is a little luck and some sedimentary rock. Igneous rock is volcanic in nature, so that won’t be likely to preserve any critters. Metamorphic rock is rock that has changed from heat and pressure, so no luck there either. But sedimentary rock is just dirt that compacted into rocks. If you go on a fossil hunt, respect private property and remember not to take anything from or do any damage to national parks.

Petrified wood- looking at the rough bark

Petrified wood- look closely and you can see the grains

Ant trapped in amber (Smithsonian)

Desert Life

This time of year, there’s usually no place in America that’s hotter than the desert Southwest. The region is known for its striking red sandstone formations, deep canyons, and ancient ruins. While the desert may seem like a barren wasteland to the casual observer, it is full of life. If you know where to look. The critters of the desert have evolved with special adaptations that allow them to survive in a harsh environment. Let’s have a look at some.

Extreme heat and scarce water are two hardships of the desert. Because of the second problem, sweating is an impractical solution to the first problem. As a workaround, the jackrabbit has large ears which are full of blood vessels. The blood vessels bring warmer blood away from the body core to cool. The large surface area of the ears also helps the cooling process (National Geographic).

Black-tailed jack rabbit (NPS)

The kangaroo rat has adapted to life without beverages. It can go an extended period without water, absorbing what it needs from its plant-based diet. Too keep cool, it lives underground and is nocturnal (Arizona-Sonora Desert Museum).

Stephen's kangaroo rat (Arizona-Sonora Desert Museum)

The various cactus species have evolved to avoid water loss. All plants lose water through their leaves in a process called transpiration. Cactus plants minimize the loss by having long, thin needles in place of the leaves we’re familiar with on trees and other leafy plants. They also have an extensive root system for maximizing water collection potential and a wide, hollow stem for water storage (BBC).

Saguaro cactus (US Forest Service)

Other desert plants have adapted as well. Shrubs and non-woody flowers survive by growing deep roots that can reach down into the water table. They have hardy seeds that can last for years before germinating. When the rare shower falls, these plants simultaneously burst to life in a brief but spectacular desert bloom (Science News for Kids).

Superbloom (National Park Service)

The Great Basin spadefoot toad has a cool adaptation for surviving in the desert. They burrow underground and remain in a state of suspended animation for years until rainfall brings it to the surface for mating and feeding. Mating pairs will lay and fertilize eggs anywhere water collects, then the race is on for the eggs to hatch and tadpoles to develop before the water evaporates. The tadpoles are cannibalistic, which might be an incentive to hurry up and grow (The Nature Conservancy).

Great Basin spadefoot toad (Idaho Fish and Game)

You probably don’t think of shrimp living in the desert. The fairy shrimp’s habitat is ephemeral (seasonal) pools that form in depressions in rock. They are tough little buggers, able to withstand extreme heat. Their eggs can survive desiccation for decades, using sugars instead of water inside the egg. The eggs can remain in place until rain activates it and it hatches, or they can be carried on the wind to a new location and hatch there when rain comes (National Park Service).

Fairy shrimp (National Park Service)

Next time you happen to be in the desert, look around for these and other fascinating critters. The desert is alive, if you look hard enough to see the life all around you.

I Wanna Rock!

Let’s explore a mystery of geology this week. I recently visited a nearby park known for its unusual rocks. Ringing Rocks features a boulder field of musically inclined rocks that ring like bells when struck with a hammer, rather than clunking like a rock.

Approaching the sonorous stones from the woods

The boulder field is surrounded by a hardwood forest. Within the forest are a few scattered boulders. None of the forest boulders were music to my ears, but supposedly the ones in the boulder field that clank are still ringing, just at a pitch too low for humans to detect. Somehow, the interaction with other boulders is what makes the ringing sound.

Boulder field of musical rocks

The rock type is olivine diabase, an iron-rich volcanic material. Being made from iron probably accounts for the metallic sound. The diabase broke into boulders thanks to Pennsylvania’s wonderful cycle of freezing and thawing. Water finds its way into a crack in the rock, expands when it freezes, and over time causes the rock to fracture.  

Me, demonstrating my musical prowess

The boulders in the field are available for you to gleefully tap with you hammer. On the one hand, this is great because anyone and everyone is free to experience the geological oddity. On the other hand, the boulders show noticeable pock marks from years of hammering. Eventually, the boulders will break. Will they lose their ability to carry a tune when that day comes? No one knows for sure.

This week's information comes from Unmuseum and S. S. McCray (Petrogenesis of the Coffman Hill diabase sheet, Easton Pennsylvania (unpublished B.S. thesis)).

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.