Tag: temperature | Page 2

6.29.15

Salmon in hot water

Chinook salmon in Alaska.

The activities are as follows:

Pacific salmon are important members of freshwater and ocean food webs. Salmon transport nutrients from the ocean to freshwater habitats, and traces of these nutrients can be found in everything from trees to bears! Salmon also support sport and commercial fisheries, and are used for ceremonial purposes by Native Americans. Climate change poses a threat to salmon populations by warming the waters of streams and rivers where they reproduce. To maintain healthy populations, salmon rely on cold, freshwater habitats and may go extinct as temperatures rise in coming decades. Warm temperatures can cause large salmon die-offs. However, some salmon individuals have higher thermal tolerance and are better able to survive when water temperatures rise.

Eggs used in QTL experiment

Salmon individuals and populations may be better able to survive in warmer waters because they have certain gene variants that help them survive under these conditions. Scientists want to know whether there is a genetic basis for the variation observed in salmon’s thermal tolerance. If differences in certain genes control variation in thermal tolerance, scientists can identify the location on the genome responsible for this very important adaptation. Once identified, management agencies could then screen for these genes in populations of salmon in order to identify individuals that could better survive in a future warmer environment. Hatchery programs could also breed thermally tolerant fish in an attempt to preserve this important fish species.

Scientists working in the lab

To identify the genes responsible for a particular trait, scientists look for Quantitative Trait Loci (QTL). A QTL is a genetic variant that influences the phenotype of a polygenic trait, such as human height or skin color, and perhaps thermal tolerance in salmon. Scientists can find QTL by conducting experimental mattings then examining the phenotypic and genetic characteristics of the offspring. In this study, parent fish from one population of salmon, some that are tolerant to warm water and some that are not, mated and produced offspring. These offspring now had a mix of genetic backgrounds from their parents, meaning that some offspring inherited genetic variants that made them more tolerant to high temperatures and some did not. Each offspring was tested for their thermal tolerances, and had their genomes sequenced. Differences in the genome between offspring that are tolerant and those that are not reveal areas of the genome that are correlated with thermal tolerance and survival in warm water. If differences in certain genes control variation in thermal tolerance, the scientists predicted they could find regions in the salmon genome that are correlated with survival in warm water.

Featured scientists: Wesley Larson, Meredith Everett, and Jim Seeb from the University of Washington

Flesch–Kincaid Reading Grade Level = 10.9

There are two scientific papers associated with the data in this Data Nugget. The citations and PDFs of the papers are below. The lab webpage can be found here.

Everett, M.V. and J.E. Seeb (2014) Detection and mapping of QTL for temperature tolerance and body size in Chinook salmon (Oncorhynchus tshawytscha) using genotyping by sequencing. Evolutionary Applications 7(4):480-492.
Larson, W.A., L.W. Seeb, M.V. Everett, R.K. Waples, W.D. Templin, J.E. Seeb (2014) Genotyping by sequencing resolves shallow population structure to inform conservation of Chinook salmon (Oncorhynchus tshawytscha). Evolutionary Applications 7(3): 355-369.

Check out these Stated Clearly videos to explore DNA and genes with students!

SaveSave

3.20.15

Springing forward

Scientist Shaun collecting phenology data in the climate change experiment. He is recording the date that the first flowers emerge for dame’s rocket.

Sean Mooney, a high school researcher, collecting phenology data in the climate change experiment. He is recording the date that the first flowers emerge for dame’s rocket.

The Reading Level 1 activities are as follows:

The Reading Level 3 activities are as follows:

Éste Data Nugget también está disponible en Español:

Every day we add more greenhouse gases to our air when we burn fossil fuels like oil, coal, and natural gas. Greenhouse gasses trap the sun’s heat, so as we add more the Earth is heating up! What does climate change mean for the species on our planet? The timing of life cycle events for plants and animals, like flowering and migration, is largely determined by cues organisms take from the environment. The timing of these events is called phenology. Scientists studying phenology are interested in how climate change will influence different species. For example, with warming temperatures and more unpredictable transitions between seasons, what can we expect to happen to the migration timings of birds, mating seasons for animals, or flowering times of plants?

Scientists collecting phenology data in the climate change experiment.

Plants are the foundation for almost all life on Earth. Through photosynthesis, plants produce the oxygen (O₂) that we breathe, food for their own growth and development, food for animals and microbes, and crops that provide food and materials for human society. Because plants are so important to life, we need to find out how climate change could affect them. One good place to start is by looking at flowering plants, guided by the question, how will increased temperatures affect the phenology of flowering? One possible answer to this question is that the date that flowers first emerge for a species is driven by temperature. If this relationship is real, we would expect flowers to emerge earlier each year as temperatures increase due to climate change. But if flowers come out earlier and earlier each year, this could greatly impact plant reproduction and could cause problems for pollinators who count on plants flowering at the same time the pollinators need the pollen for food.

Shaun, Mark, Elizabeth, and Jen are scientists in Michigan who wanted to know if higher temperatures would lead to earlier flowering dates for plants. They chose to look at flowers of dame’s rocket, a leafy plant that is related to the plants we use to make mustard! Mark planted dame’s rocket in eight plots of land. Plots were randomly assigned to one of two treatments. Half of the plots were left to experience normal temperatures (normal), while the other four received a heating treatment to simulate climate change (heated). Air temperatures in heated plots increased by 3°C, which mimics climate change projections for what Michigan will experience by the end of the century. Mark, Elizabeth, and Jen measured the date that each plant produced its first flower, and the survival of each plant. The scientists predicted that dame’s rocket growing in the heated plots would flower earlier than those in the normal plots.

Featured scientists: Shaun Davis from Thornapple Kellogg Middle School and Mark Hammond, Elizabeth Schultheis, and Jen Lau from Michigan State University

Flesch–Kincaid Reading Grade Level = The Reading Level 3 activity has a score of 9.2; the Level 1 has a 6.4.

Flowers of Hesperis matronalis (dame’s rocket), a species of mustard that was introduced to the U.S. from Eurasia.

Additional teacher resources related to this Data Nugget include:

If you would like your students to interact with the raw data, we have attached the original data here. The file also includes weather data over the course of the experiment if students want to ask and explore independent questions.

For a lesson plan that uses citizen science phenology datasets to examine changes in phenology over 30+ year timespans, and address the scientific question, “Do we see evidence for climate change in the phenology of plants and animals?”, click here.
Many phenology datasets are freely available online (many collected by citizen scientists). These datasets are extremely useful because scientists (and your students!) can examine average trends in timing shifts over periods of decades and often in different regions. Phenology datasets available online:
- Lilac flowering phenology dataset
- Ice cover duration for two Michigan lakes
- Nature’s Notebook: A national plant and animal phenology observation program, where students can contribute their phenology data
- ebird: A global bird observation program through Cornell University, students can become citizen scientists and enter data on local bird counts
- hummingbird.net: A place to learn about attracting, watching, feeding, and studying the hummingbirds that breed in North America
NY Times article on research showing what happens when climate change shifts phenology – “5 Plants and Animals Utterly Confused by Climate Change“
Webinar, hosted by Data Nuggets and DataClassroom, exploring the research and data behind this activity.
Webinar exploring how plants respond to climate change, featuring this Data Nugget and LTER scientists!

SaveSave

3.25.14

Coral bleaching and climate change

A Pacific coral reef with many corals

The activities are as follows:

Éste Data Nugget también está disponible en Español:

Corals are animals that build coral reefs. Coral reefs are home to many species of animals – fish, sharks, sea turtles, and anemones all use corals for habitat! Corals are white, but they look brown and green because certain types of algae live inside them. Algae, like plants, use the sun’s energy to make food. The algae that live inside the corals’ cells are tiny and produce more sugars than they themselves need. The extra sugars become food for the corals. At the same time, the corals provide the algae a safe home. The algae and corals coexist in a relationship where each partner benefits the other, called a mutualism: these species do better together than they would alone.

When the water gets too warm, the algae can no longer live inside corals, so they leave. The corals then turn from green to white, called coral bleaching. Climate change has been causing the Earth’s air and oceans to get warmer. With warmer oceans, coral bleaching is becoming more widespread. If the water stays too warm, bleached corals will die without their algae mutualists.

Scientist Carly working on a coral reef

Carly is a scientist who wanted to study coral bleaching so she could help protect corals and coral reefs. One day, Carly observed an interesting pattern. Corals on one part of a reef were bleaching while corals on another part of the reef stayed healthy. She wondered, why some corals and their algae can still work together when the water is warm, while others cannot?

Ocean water that is closer to the shore (inshore) gets warmer than water that is further away (offshore). Perhaps corals and algae from inshore reefs have adapted to warm water. Carly wondered whether inshore corals are better able to work with their algae in warm water because they have adapted to these temperatures. If so, inshore corals and algae should bleach less often than offshore corals and algae. Carly designed an experiment to test this. She collected 15 corals from inshore and 15 from offshore reefs in the Florida Keys. She brought them into an aquarium lab for research. She cut each coral in half and put half of each coral into tanks with normal water and the other half into tanks with heaters. The normal water temperature was 27°C, which is a temperature that both inshore and offshore corals experience during the year. The warm water tanks were at 31°C, which is a temperature that inshore corals experience, but offshore corals have never previously experienced. Because of climate change, offshore corals may experience this warmer temperature in the future. After six weeks, she recorded the number of corals that bleached in each tank.

Featured scientist: Carly Kenkel from The University of Texas at Austin

Flesch–Kincaid Reading Grade Level = 8.0

There are two scientific papers associated with the data in this Data Nugget. The citations and PDFs of the papers are below.

Kenkel CD, E Meyer, MV Matz (2013) Gene expression under chronic heat stress in populations of the mustard hill coral (Porites astreoides) from different thermal environments. Molecular Ecology 22:4322-433
Kenkel CD, G Goodbody-Gringley, D Caillaud, SW Davies, E Bartels, MV Matz (2013) Evidence for a host role in thermotolerance divergence between populations of the mustard hill coral (Porites astreoides) from different reef environments. Molecular Ecology 22:4335-4348

If your students are looking for more data on coral bleaching, check out HHMI BioInteractive’s classroom activity in which students use authentic data to assess the threat of coral bleaching around the world. Also, check out the two videos below!

A video in BioInteractive’s “Scientists at Work” series showing researchers working on the same hypothesis in another part of the world: Steve Palumbi & Megan Morikawa Study Coral Reef Damage in American Samoa

Another BioInteractive video, appropriate for upper level high school classrooms. Visualizes the process of coral bleaching at different scales. Video includes lots of complex vocabulary about cells and the process of photosynthesis.

SaveSave

1.10.14

The ground has gas!

Measuring nitrogen (N2O) gas escaping from the soil in summer. Photo credit: Julie Doll, Michigan State University

The activities are as follows:

If you dig through soil, you’ll notice that soil is not hard like a rock, but contains many air pockets between soil grains. These spaces in the soil contain gases, which together are called the soil atmosphere. The soil atmosphere contains the same gases as the atmosphere that surrounds us above ground, but in different concentrations. It has the same amount of nitrogen, slightly less oxygen (O₂), 3-100 times more carbon dioxide (CO₂), and 5-30 times more nitrous oxide (N₂O, which is laughing gas!).

Measuring nitrogen (N2O) gas escaping from the soil in winter. Photo credit: Julie Doll Michigan State University.

Nitrous oxide and carbon dioxide are two greenhouse gasses responsible for much of the warming of global average temperatures. Sometimes soils give off, or emit, these greenhouse gases into the earth’s atmosphere, adding to climate change. Currently scientists are working to figure out why soils emit different amounts of these greenhouse gasses.

During the summer of 2010, Iurii and his fellow researchers at Michigan State University studied nitrous oxide (N₂O) emissions from farm soils. They measured three things: (1) the concentration of nitrous oxide 25 centimeters below the soil’s surface (2) the amount of nitrous oxide leaving the soil (3) and the average temperature on the days that nitrous oxide was measured. The scientists reasoned that the amount of nitrous oxide entering the atmosphere is positively associated with how much nitrous oxide is in the soil and on the soil temperature.

Featured scientist: Iurii Shcherbak from Michigan State University

Flesch–Kincaid Reading Grade Level = 9.2

More information on the research associated with this Data Nugget can be found here.

Data associated with this Data Nugget can be found on the MSU LTER website data tables under GLBRC Biofuel Cropping System Experiment. Bioenergy research classroom materials can be found here. More images can be found on the LTER website.

SaveSave