Background:
The extreme climate of Death Valley is attributable to its location on the leeward (downwind) side of the Sierra Nevada Mountains in central California. Air that has been warmed and moistened by its passage over the Pacific Ocean is driven up over the Sierras as it is carried eastward by the prevailing southwesterly winds of the northern mid-latitudes.

As the air rises up over the mountains, it expands and cools, triggering condensation that forms clouds and causes precipitation on the windward (west facing) slopes. At the same time, the latent heat stored in the water vapor in the air is released by the condensation process, adding measurable heat to the air As the now warmer and drier air continues its eastward journey over the peaks and begins its descent into the valleys on the leeward side of the range, its temperature rises as it is compressed under the higher atmospheric pressure of the lower elevations. The fact that Death Valley lies below sea level causes even more compression of the descending air, creating a very hot and dry “rain shadow desert” in Death Valley.

Segments from the NATURE episode “Life in Death Valley” provide students with dramatic examples of the effects of the atmospheric and geologic conditions that come together to produce one of the most extreme environments on earth.

Suggested Focus Questions:

Clip 1: You Can Die Here

1. Describe the location and size of Death Valley.
2. Describe the climate of Death Valley.
3. Research the location of two other “rainshadow deserts” in the world. Why are rainshadow deserts located where they are?

Clip 2: Clouds & Currents

1. What drives the circulation of air in Death Valley?
2. Why is the air that comes down the mountainsides into the valley so dry?
3. Air at a particular elevation on the windward side of the mountains is cooler than air at the same elevation on the leeward side. How can that difference be explained?

Clip 3: Runnin’ with the Devil

1. What are the threats to human survival in Death Valley?
2. What preparations can people take to ensure their survival in Death Valley?
3. What adaptations might help plants and animals that live in Death Valley to survive?

Downloadable QuickTime versions of the video segments:
(Note: To download a video, right-click on the video title and click “Save Link As…” or “Save Target As…”. On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Clip 1, “You Can Die Here.”

Clip 2, “Clouds & Currents.”

Clip 3, “Runnin’ with the Devil.”

GRADE LEVEL: 8-10

TIME ALLOTMENT: Two 45-minute class periods

OVERVIEW: Death Valley lies just to the east of the high peaks of the Sierra Nevada Mountains of central California. At 282 feet below sea level, it is the lowest point in the United States. It is also both the hottest and driest place in the United States. Death Valley is an example of a “rain shadow desert,” one of many such deserts located in the lee of high mountain ranges around the world. This lesson will help students to evaluate how the interactions of air, moisture, wind, and topography combine to create an environment of such extremes.

Utilizing a directed inquiry approach, students will discover precipitation patterns in the southwest United States. Using clips from the Nature episode “Life in Death Valley,” precipitation maps and Google Maps satellite images (or an optional Google Earth tour) students will describe the differences in precipitation on the west and east flanks of the Sierra Nevada. Through classroom discussion, students will then explore the reasons for those differences.

SUBJECT MATTER: Earth Science, Meteorology, Climate, Deserts, Rain Shadow Deserts

LEARNING OBJECTIVES:

Students will be able to:

• Read and interpret a Planetary Winds diagram
• Describe the precipitation patterns on the windward and leeward sides of mountains
• Explain the reasons for the precipitation patterns on the windward and leeward sides of mountains
• Relate knowledge about temperature and pressure to meteorological effects

STANDARDS AND CURRICULUM ALIGNMENT

National Science Education Standards

CONTENT STANDARD D: AS A RESULT OF THEIR ACTIVITIES IN GRADES 9-12, ALL STUDENTS SHOULD DEVELOP AN UNDERSTANDING OF:

ENERGY IN THE EARTH SYSTEM

• Global climate is determined by energy transfer from the sun at and near the earth’s surface. This energy transfer is influenced by dynamic processes such as cloud cover and the earth’s rotation, and static conditions such as the position of mountain ranges and oceans.

GEOCHEMICAL CYCLES

• The earth is a system containing essentially a fixed amount of each stable chemical atom or element. Each element can exist in several different chemical reservoirs. Each element on earth moves among reservoirs in the solid earth, oceans, atmosphere, and organisms as part of geochemical cycles.
• Movement of matter between reservoirs is driven by the earth’s internal and external sources of energy. These movements are often accompanied by a change in the physical and chemical properties of the matter. Carbon, for example, occurs in carbonate rocks such as limestone, in the atmosphere as carbon dioxide gas, in water as dissolved carbon dioxide, and in all organisms as complex molecules that control the chemistry of life.

New York State Regents Core Curriculum Alignments:

Physical Setting: Earth Science Core Curriculum

Mathematics, Science, and Technology

Standard 2: Information Systems
Students will access, generate, process, and transfer information, using appropriate technologies.

Key Idea 1. Information technology is used to retrieve, process, and communicate information as a tool to enhance learning

Standard 4
Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.

Key Idea 2. Many of the phenomena that we observe on Earth involve interactions among components of air, water, and land.

Performance Indicator 2.1c
Weather patterns become evident when weather variables are observed, measured, and recorded. These variables include air temperature, air pressure, moisture (relative humidity and dewpoint), precipitation (rain, snow, hail, sleet, etc.), wind speed and direction, and cloud cover.

Performance Indicator 2.1e
Weather variables are interrelated. Temperature and humidity affect air pressure and probability of precipitation. Air pressure gradient controls wind velocity.

Performance Indicator 2.2c
A location’s climate is influenced by latitude, proximity to large bodies of water, ocean currents, prevailing winds, vegetative cover, elevation, and mountain ranges.

Key Idea 4. Energy exists in many forms, and when these forms change energy is conserved.

MEDIA COMPONENTS:

Video

NATURE: Life in Death Valley, selected clips

Clip 1, “You Can Die Here.”

Environmental conditions of Death Valley, CA.

Clip 2, “Clouds & Currents.”

Cloud formations over the Sierra Nevada Mountains.

Clip 3, “Runnin’ with the Devil.”

Running a race in Death Valley must be done with extreme caution!

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Web Sites

Planetary Winds Diagram
A diagram from the New York State Education Department’s Earth Science Reference Tables (ESRT).

Relief Map of California
A color-coded map from the United States Geological Survey showing terrain elevations in California.

California’s Average Annual Precipitation Map
A color-coded map from Oregon State University showing average annual rainfall in California.

MATERIALS:

For each student:

• A copy of the Planetary Winds diagram from page 14 of the Earth Science Reference Tables (ESRT)
• “Rainshadow Deserts Student Organizer “(PDF) (RTF)
• “Precipitation Student Organizer” (PDF) (RTF)
• Relief Map of California, color copy
• California’s Average Annual Precipitation Map, color copy

For each group of 3-4 students:

• “Global Deserts Student Organizer” (PDF) (RTF)

For the classroom:

• One computer with broadband internet access, connected to a LCD projector and screen.
• One overhead projector or similar digital projection device.
• Rainshadow Deserts Student Organizer – Teacher Answer Key (PDF) (RTF)
• Precipitation Student Organizer – Teacher Answer Key (PDF) (RTF)
• Optional Google Earth tour to accompany this classroom exercise: rainshadow.kmz
• Additional instructions for optional Google Earth tour. (PDF) (RTF)

PREP FOR TEACHERS

Prior to teaching this lesson, you will need to:

Preview all of the video clips and Web sites used in the lesson.

Download the video clips used in the lesson to your classroom computer, or prepare to watch them using your classroom’s Internet connection.

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Make copies of all print materials as outlined in the materials section. Make sure you can quickly and reliably switch the screen from the computer display to the overhead or digital projection display. If using the optional Google Earth Tour for Learning Activity One, follow these additional instructions: (PDF) (RTF).

Next: Proceed to Activities

Coastal paradise is showcased in Living Edens: Big Sur – California’s Wild Coast, a special presentation of NATURE.

California is the land of Disney, Hollywood, and freeway traffic jams. But on a much grander scale, it’s also the land of natural marvels, including a coastal paradise where wildlife and flora thrive in an unspoiled environment. This magnificent region is explored in intimate detail in Living Edens: Big Sur.

On the 100-mile stretch of coastland south of the Monterey Peninsula, the filmmaker, Bruce Reitherman, reveals a variety of wildlife that has found refuge and hope here, including such rare and endangered birds as the California condor and the peregrine falcon. The return of the condor to Big Sur testifies to the success of one of the most ambitious captive breeding programs in history.

Ocean mammals too have found a hospitable haven in Big Sur. Thousands of elephant seals come ashore each winter, the females to give birth and the males to battle for the right to father the next generation. Sea otters are filmed using rocks as anvils to pry a rich meal from even the most resistant of mussels.

Inland, Big Sur encompasses forests of majestic ancient redwoods and oak woodlands, home to the acorn woodpecker, which is sustained through the winter by the oak tree’s nut-like fruit.

Online content for Living Edens: Big Sur – California’s Wild Coast was originally posted November 2002.

A killer is stalking the Big Sur coast. And if it isn’t stopped, it could forever remake the scenic landscape featured in NATURE’s Living Edens: Big Sur – California’s Wild Coast.

The killer is a mysterious fungus, and its victims are California’s beloved oak trees, the leafy, stout-stalked emblems of the Big Sur coast. Since researchers first discovered the fungus in 1995, they’ve been struggling to understand and control Sudden Oak Death — so far with little success. In the meantime, tens of thousands of oak trees have succumbed to the disease. And scientists worry that other kinds of trees, including the towering coast redwood, could be next.

Thousands of Big Sur’s oak trees have succumbed to a killer fungus. The killer’s path is easily found. In Pfeiffer Big Sur State Park, for instance, rangers have had to cut down hundreds of trees, piling the parched logs into heaps to be burned. Thousands more stand dead on nearby hillsides. Campsites once shaded by oaks are now speckled with stumps and blasted by sunlight. Similar landscapes can be found across hundreds of miles of California.

In a bid to stop its killing spree, disease detectives have been racing to profile the stalker. An early break came when researchers David Rizzo of the University of California, Davis, and Matteo Garbelotto of the University of California, Berkeley identified Sudden Oak Death as a previously unknown strain of fungi from the genus Phytophthora (Phy-TOFF-thoruh), which means plant killer in Latin. They also determined that the killer — called Phytophthora ramorum — comes from a dangerous family: one relative caused the Irish potato famine, and another is known to have killed cedar trees in northern California and southern Oregon, eucalyptus trees in Australia, and oaks in Mexico, Spain, and Portugal.

The killer’s origins, however, are unclear. It might have recently hitchhiked into California aboard a potted plant or nursery-raised tree. Researchers are suspicious because it matches a fungus found on rhododendron shrubs in Europe. But it also could be a native fungus gone bad, turned killer by climate or environmental changes.

Thousands of Big Sur’s oak trees have succumbed to a killer fungus.

For the time being, Sudden Oak Death has spared California’s redwoods. Whatever its past, researchers are more worried about Sudden Oak Death’s future. So far, the disease has hit hardest at several costal species of oaks — including tanoak (Lithocarpus densiflorus), coast live oak (Quercus agrifolia), and California black oak (Quercus kelloggii). The wounds are easy to spot: the fungus enters through the trunk and then causes the formation of bleeding cankers. “We see a whole range of symptoms in the field, from nasty cankers on the trunks of oaks to minor spots on the leaves of the buckeye,” says Rizzo. But the weakest trees don’t last long.

So far, other species have been spared. But, overall, California is home to 16 of the 17 species known to be vulnerable to the disease. And those include two of California’s most highly prized trees — coast redwood and Douglas fir.

At the present time, there is little evidence the towering redwoods and firs are being harmed. But “we cannot say what the effects of the infection will be long-term,” says Garbelotto. “It seems that some species are able to tolerate the pathogen better than others,” adds Rizzo.

More study — and more time — will be needed to solve this ecological mystery. “It may take years before we can start answering questions about the ecological impacts of the disease,” says Rizzo. In the meantime, those admiring Big Sur’s signature oaks can only wait, and hope for the best.

Big Sur’s rugged mountains, crashing surf, and abundant wildlife have captivated generations of visitors. But the region has also attracted scientists bent on understanding this remarkable biological melting pot, where plants and animals from dramatically different ecosystems often mingle side by side. One biologist who has taken a close look is Paul Henson, who lived in the region in the 1980s and, with Don Usner, wrote The Natural History of Big Sur (University of California Press, 1996).

Big Sur attracts scientists due to its status as a biological melting pot. In no other part of the world do fog-loving coastal redwoods thrive on one slope of a canyon while arid-climate yuccas grow on the other, the book notes. Similarly, sea otters and cormorants live near dry-climate creatures like canyon wrens and whiptail lizards.

Henson, who now works for the U.S. Fish and Wildlife Service overseeing biological studies in Hawaii and other Pacific Islands, spoke with NATURE about Big Sur’s remarkable diversity.

How did you come to write this book?

I earned my undergraduate degree at the University of California, Santa Cruz, and did a lot of work at a university reserve called Big Creek that covers a big chunk of the Big Sur coast. Then, in the mid-1980s, I got a job doing sea otter research. During my down time, we started on the natural history guide. We realized that there was lots of good information floating around, but it hadn’t been consolidated in one place, and made accessible to scientists and understandable to regular readers. So we decided to do it.

Big Sur attracts scientists due to its status as a biological melting pot.

What makes Big Sur unusual?

For lack of a better term, it represents a kind of harmonic convergence of different ecological zones. It’s where the north meets the south, for instance. What’s called the Oregonia province to the north meets the Californian province to the south. So you have redwood trees meeting cacti and intermingling. You have northern and southern species of marine alga. One minute, you are hiking along in a wet cool canyon, and all of a sudden there will be a cactus. One minute it smells like Oregon and the next it smells like Mexico.

The geology plays are role, right?

The geology and topography forms the basis for it all, and it has driven geologists crazy for years. It’s incredibly jumbled and complicated. You have all these faults and slices of rock that have moved over time. And then on top of that you have a very interesting climate. Big Sur has a Mediterranean climate, which it shares with just four or five other areas in the world. It’s a climate that is extremely conducive to a lot of plants doing well. Taken together, those things make it one of the most ecologically fascinating and diverse areas in North America.

Big Sur is one of the most ecologically diverse areas in North America. Big Sur has its share of rare species …

Yes. In the 1800s, it attracted a lot of famous botanists because there are plants there that grow nowhere else. The Santa Lucia mountains have a lot of unique species because, at times, that area has been an island. So plants and animals that lived there have been cut off from other populations and evolved in their own direction. Probably the most famous species is the Santa Lucia fir tree, which is found in just a few canyons and nowhere else in the world. It looks like a tree in a Dr. Seuss book — the top droops over and it has these interesting cones.

Do you have a favorite spot in Big Sur?

Probably the Little Sur River Valley in the Ventana Wilderness. It has such a great combination of giant redwood trees and really dry chaparral. It’s one of those places where you have very different ecosystems within spitting distance of each other.

How about a favorite animal?

Probably golden eagles. The raptor [bird of prey] populations there are amazing. There are places where you can sit on a hillside, look out, and see five or six different raptors in a minute — golden eagles, red shouldered hawks, kites, red tailed hawks, kestrels. It’s a great show.

Big Sur, California
http://www.bigsurcalifornia.org/
Comprehensive site from the Big Sur Chamber of Commerce.

California Oak Mortality Task Force
http://www.cnr.berkeley.edu/comtf/
A non-profit organization leading the effort to understand Sudden Oak Death.

Elephant Seals
http://www.bigsurcalifornia.org/elephant-seals.html
The king of Big Sur beaches.

A Guide to California’s Big Sur
http://jrabold.net/bigsur/
Maps and more from John Rabold.

Gray Whale
http://www.bigsurcalifornia.org/whalesgray.html
Seen from Big Sur lookouts from December through April.

Big Sur Beaches
http://www.bigsurcalifornia.org/beaches.html
Some of the most beautiful in the world.

Books

Henson, Paul et al. THE NATURAL HISTORY OF BIG SUR. Berkeley, CA: University of California Press, 1996.

Karman, James et al. STONES OF THE SUR. Palo Alto, CA: Stanford University Press, 2001.

Schaffer, Jeffrey. HIKING THE BIG SUR COUNTRY: THE VENTANA WILDERNESS. San Francisco: Wilderness Press, 1988.

Steakley, Douglas. BIG SUR & BEYOND: THE LEGACY OF THE BIG SUR LAND TRUST. San Francisco: Graphic Arts Center Publishing Co., 2001.

Ulrich, Larry. BIG SUR TO BIG BASIN: CALIFORNIA’S DRAMATIC CENTRAL COAST. San Francisco: Chronicle Books, 1998.