8.28.24

Guppies on the move

Guppies in the lab. Photo Credit: Eva Fischer.

The activities are as follows:

  • Teacher Guide
  • Student activity, Graph Type A, Level 3
  • Student activity, Graph Type B, Level 3
  • Student activity, Graph Type C, Level 3
  • Grading Rubric

Animal parents often choose where to have their offspring in the place that will give them the best chance at success. They look for places that have plentiful food, low risk of predation, and good climate.

Even though parents pick out these spots, individuals often move away from their birthplace at some point in their lives. Why do animals move away? There are risks that come with moving from one place to another. It can be dangerous to go through unknown places – potentially stumbling into predators or being exposed to diseases. But there can also be benefits to moving, such as discovering a better spot to live as an adult, finding mates, and spreading out to reduce competition.

As someone who loves to travel and has lived in four different countries, Isabela can relate! Isabela likes to see new places, try new foods, and learn new languages. But there can be drawbacks, and occasionally she finds it hard to be in a completely new place. Sometimes people don’t understand her accent, or she can’t understand them. She also misses her family when she is away. Knowing that traveling and moving can have such highs and lows for herself, Isabela wanted to know more about what motivates animals to seek out new places.

To follow her curiosity, Isabela found a graduate advisor who was also interested in animal movement. She joined Sarah’s lab because she had already collected data on the movement of small tropical fish called guppies. Sarah is part of a large collaborative project, where researchers from all over the world come together in Trinidad to study these fish populations.

When Sarah first started collecting data in this system, she wanted to track how far guppies move from one place to the next. She used established protocols from previous work in this system to set up a study. With the help of a team, she captured every fish in two similar streams for replication. Every fish that was caught was marked with a small tattoo so the research team could recognize it if it was found again in the future. She did this same procedure every month for 14 months. Each time she sampled the fish, she recorded the individuals that she found and where they were found.

Isabela used this dataset to ask whether guppies benefit from moving from one place to another. In this study, she focused on one type of benefit: having a higher number of offspring. It is through reproduction that animals are able to pass on their genes, so the more offspring an individual fish has, the more successful it is.

First, Isabela used the existing dataset to find out how far each fish moved: if Fish 1 was captured in Portion A of a stream in February and then in Portion B of the same stream in March, Isabela knew it had to move from A to B. She could use the timepoints to estimate how far each individual had traveled that month.

Second, Isabela used genetics to find out how many offspring each fish had. She looked at genetic markers to determine familial relationships between individuals in each stream. For example, two fish that shared 50% of their genes were probably a parent and an offspring. In this case, the older individual would be marked as the parent. Isabela used the genetic information to build a pedigree, or a chart that documents each generation of a population. That way she could track how many offspring each parent had produced.

She used these data to answer her question on whether there are benefits to traveling more. Isabela also wanted to compare whether the potential benefits of dispersal differed across the sexes. Males have to compete for females in order to mate. Isabela wanted to know if males that moved more were able to mate with more females and have more offspring.

Featured scientist:

Featured scientists: Isabela Borges (she/her) and Sarah Fitzpatrick (she/her) from the Kellogg Biological Station at Michigan State University.

Flesch–Kincaid Reading Grade Level = 

Additional teacher resources related to this Data Nugget include:

8.24.24

Do urchins flip out in hot water?

Erin in the urchin lab at UC-Santa Barbara.

The Reading Level 1 activities are as follows:

The Reading Level 3 activities are as follows:

Teacher Resources:

Imagine you are a sea urchin. You’re a marine animal that attaches to hard surfaces for stability. You are covered in spikes to protect you from predators. You eat giant kelp – a type of seaweed. You prefer temperate water, typically between 5 to 16°C. But you’ve noticed that some days the ocean around you feels too hot. 

These periods of unusual warming in the ocean are called marine heatwaves. During marine heatwaves, water gets 2-3 degrees hotter than normal. That might not sound like much, but for an urchin, it is a lot. The ocean’s temperature is normally very consistent, so urchins are used to a small range of temperatures. Urchins are cold-blooded. This means they can’t control their own body temperature and rely on the water around them. Whatever temperature the ocean water is, they are too!

Erin is a scientist who studies how environmental changes, like temperature, affect organisms. Erin first got excited about urchins when she interned with a research lab. When she started graduate school, she learned more about their biology and started to ask questions about how urchins would react to marine heatwaves. Hot water can speed up animals’ metabolisms, making them move and eat more. However, warmer temperatures can also cause stress, potentially causing urchins to be clumsier and confused.

Erin getting ready to scuba dive to look for urchins off the California coast.

One summer, two science teachers, Emily and Traci, came to California to work in the same lab as Erin. Emily and Traci wanted to do science research so they can share their experience with their students.  As a team, they decided to test whether marine heat waves could be stressing urchins by looking at a simple behavior that they could easily measure. Healthy urchins have a righting instinct to flip over to orient themselves “the right way” using their sticky tube feet.

The research team predicted that urchins would be slower to right themselves in warmer temperatures. However, they also thought the response could depend on the temperature the urchins were used to living in. If the urchins had been acclimated to higher temperatures, they might not be as strongly affected by the heatwaves.

Together, Erin, Emily, and Traci took 20 urchins into her lab and split them into 2 groups. Ten were kept at 15°C, the ocean’s normal temperature in summer. The other ten were kept at 18°C, a marine heatwave temperature. They let the urchins acclimate to these temperatures for 2 weeks. They tested how long it took each urchin to right itself after being flipped over. They did this at three temperatures for each urchin: 15°C (normal ocean), 18°C (heatwave), and 21°C (extreme heatwave). They worked together to test the urchins three times at each temperature to get three replicates. Then they calculated the average of each urchin’s responses.

Featured scientists: Erin de Leon Sanchez (she/her) from University of California – Santa Barbara, Emily Chittick (she/her), and Traci Kennedy (she/her) from Milwaukee Public Schools.

Flesch–Kincaid Reading Grade Level = The Content Level 3 activity has a score of 7.9 ; the Level 1 has a score of 5.9

Additional teacher resources related to this Data Nugget include:

  • Here is a video of a parrotfish finding and eating an urchin. Show this video to emphasize how important it is for urchins to be able to right themselves!
Video of a trial where the researchers flipped over an urchin and timed how long it took the urchin to flip back over.
Watch how sea urchins use items from their environment to cover themselves.
8.2.24

A plant breeder’s quest to improve perennial grain

Hannah takes notes on the date of flowering in a Kernza® field in Southwest Minnesota.

The activities are as follows:

Kernza® is a new grain crop that is similar to wheat. It can be ground into flour and used in bread, cookies, crackers and more! Unlike wheat, the rest of the plant can be eaten by livestock such as cattle. Another difference is that Kernza® is a perennial, meaning it grows in the ground for multiple years, whereas annual wheat only grows for one year. However, the challenge is that annual wheat makes more grain and is easier to harvest and sell. This means farmers currently prefer growing annual wheat over Kernza®.

One way to address this mismatch between annual and perennial crops is through selective breeding. This is when humans select individual plants with traits that are desirable for a specific reason. This group of individuals are strategically bred together. The breeder’s goal is to shift the traits over generations. Scientists have only been working on breeding Kernza® for the past few decades; in comparison, humans started selecting annual wheat traits over 10,000 years ago! That is a lot of time to get the traits we are looking for.

Kernza® breeders are working on improving the same traits that have already been improved in annual wheat, including larger seed size. Kernza® scientists follow two main steps to breed plants 1) they select the best individuals from the population and 2) they intercross those individuals to create the next generation, or breeding cycle. With each breeding cycle, plant breeders see a slight improvement in the traits they selected.

Breeders can select plants based on phenotypes, genotypes, or both. Historically, plant breeders have selected based on desired phenotypes, or visible traits, only. Modern plant breeding can take advantage of the fact that we can now look at genotypes, or the genetic makeup, of individual plants quickly and at low costs. Scientists can use this information to make quicker breeding improvements, so we don’t have to wait another 10,000 years for high-yielding Kernza®!

A scientist pipettes DNA samples into an agarose gel to separate samples based on genotype using gel electrophoresis.

Hannah is a scientist currently working on Kernza®. Hannah’s passion for plant breeding was ignited during her high school years. She discovered the captivating world of genetics in her AP Biology class. It was then that she first realized the potential for breeding crop plants to make them more productive and viable for human consumption.

Hannah decided to join other scientists who work on Kernza® at the University of Minnesota. Here, scientists have completed four breeding cycles and are about to start the fifth. Hannah wanted to see whether different genetic makeups (genotypes) lead to differences in seed size (phenotypes). Her goal was to look at each plants’ phenotype and genotype for seed size.

To genotype a plant, scientists collect a small piece of leaf tissue, extract the DNA, and send the DNA to a lab for sequencing. This process tells scientists the genetic makeup that ultimately leads to the traits that we see. Specifically, sequencing data identifies nucleotides, or genetic building blocks of each plant’s DNA. Plants have thousands of genes, which are made up of the DNA nucleotides A, T, C, and G.

Sequencing data can be recorded in several ways. One common way is as SNP data, or Single Nucleotide Polymorphism data. You can think of SNP data as the recipe for proteins. In a SNP dataset, each SNP represents a difference in a nucleotide. Similar to using a different ingredient in a recipe, different nucleotides can result in a different phenotype.

By looking at SNP data, plant breeders can identify differences in genotypes that lead to certain phenotypes. Hannah started by evaluating 1,000 Kernza® plants from the first four breeding cycles. Data on phenotypes had already been recorded for these plants. Hannah then collected SNP data to determine their genotypes as well. She was looking for a pattern between genotypes and phenotypes. If she sees that different genotypes have different phenotypes, scientists can then rely on genotypes to select individuals to breed in future breeding cycles.

Featured scientist: Hannah Stoll (she/her) from the University of Minnesota

Flesch–Kincaid Reading Grade Level = 8.9

Additional teacher resources related to this Data Nugget include:

8.1.24

Poop, poop, goose!

Cackling Goose next to a pile of goose poop, or feces
Cackling Goose next to a pile of goose poop, or feces. Photo by Andrea Pokrzywinski.

The activities are as follows:

Each spring, millions of birds return to the Yukon-Kuskokwim Delta. This delta is where two of the largest rivers in Alaska empty into the Bering Sea. It is also one of the world’s most significant habitats for geese to breed and raise their young. 

With all these geese coming together in one area, they create quite a mess – they drop tons of poop onto the soil. So much poop in fact, that scientists wonder whether poop from this area in Alaska could have a global impact! Climate change is a worldwide environmental issue that is caused by too many greenhouse gasses being released into our atmosphere. Typically, we think of humans as the cause of this greenhouse gas release, but other animals can contribute as well. 

When poop falls onto the soil it is decomposed by bacteria. Bacteria release methane (CH4), a potent greenhouse gas. The more geese there are, the more poop they will produce and the more food there will be for soil bacteria. By increasing the amount of greenhouse gasses that are released by soil bacteria, geese might actually indirectly contribute to global climate change.

Trisha is an ecosystem ecologist who scoops goose poop for research projects. Her research is looking into whether animals, other than humans, can change the carbon cycle. Trisha teamed up with Bonnie, a fellow ecosystem ecologist. Bonnie studies how matter moves between the living parts of the environment, such as plants and animals, and the nonliving parts. She is especially interested in how bacteria in the soil play a role in the carbon cycle.

Together, the team designed a three-year project to figure out the effects of goose poop on the carbon cycle. Each summer, a large team of researchers spend 90 days camping on remote sites near the Yukon-Kuskokwim Delta. The team scooped up poop from nearby goose habitats to use in their experiments. They set up six control plots where they added no poop and six treatment plots where they added poop. From these twelve plots, the team measured methane emissions from the soil. Methane was measured as methane flux in micromoles, or µM. These data helped them determine how ecosystems respond to geese by measuring whether goose poop affects methane production by soil bacteria.  

Featured scientists: Trisha Atwood of Utah State University and Bonnie Waring of Imperial College. Written by Andrea Pokrzywinski.

Flesch–Kincaid Reading Grade Level = 8.7

Additional teacher resources related to this Data Nugget include:

7.17.24

Sink or source? How grazing geese impact the carbon cycle

Tricia (left) installing carbon dioxide plots in the field.

The activities are as follows:

“If it wasn’t for the geese, you and I would not be here today because our ancestors would not have made it. When long, hard winters emptied people’s food caches early, starvation loomed. Return of geese in April saved us.” – Chuck Hunt, born and raised on the Yukon-Kuskokwim Delta

Spring geese are an essential food source for subsistence communities like Chevak, Alaska. Elders in western Alaska Native communities have observed a decrease in geese returning to their villages over time. These changes affect the local communities and could also affect the local ecosystem.

One way geese change their environment is by eating grass. In the Yukon-Kuskokwim Delta in western Alaska, birds from every continent on Earth migrate to this sub-Arctic habitat to lay their eggs and raise their young. Once they arrive, geese eat a ton of grass. They graze only in specific areas, called grazing lawns, leaving the rest of the vegetation alone.

When geese graze on wetland plants, they remove plant matter, potentially decreasing the amount of carbon dioxide, or CO2, that is released during photosynthesis. As plants photosynthesize, they absorb CO2 from the atmosphere and turn it into glucose (a sugar) and oxygen. Gross primary production is the total amount of energy that plants capture from sunlight to grow and live before they use up some of that energy for themselves. Plants can slow climate change by removing CO2 from the atmosphere and turning it into plant matter, like leaves and roots.

A scientist mimics geese grazing by clipping the grass.

Trisha is a scientist who became interested in ways that animals can affect the carbon cycle through their interactions with the environment. She wondered whether fewer geese returning to western Alaska could have global consequences that extend beyond remote communities. She thought that if geese ate enough grass, they may limit photosynthesis. This is important because it could change whether this ecosystem is a carbon sink or a carbon source. An ecosystem is called a carbon sink if it absorbs more CO2 through photosynthesis than it releases through respiration. Alternatively, an ecosystem can be a carbon source if more CO2 is released than absorbed. We want ecosystems to be carbon sinks because then they keep CO2 out of the atmosphere, where it contributes to global warming.

To test her idea, Trisha teamed up with fellow scientists Bonnie, Karen, and Jaron to take a closer look at how grazing grass influences whether the Y-K Delta ecosystem is releasing or absorbing CO2. To do their experiment they had to get creative. They considered getting a lot of geese, bringing them to an ungrazed area, and letting them chow down. However, it’s hard to capture geese and get them to graze exactly where you want. So instead, the research team simulated the effects of geese by cutting the grass to mimic nibbling and then gently vacuuming the pieces of grass to remove them.

The “Carbon and Geese” scientist team.

The team set up six different experimental areas. Inside each area were two plots: one that was left ungrazed, and the other which was artificially grazed. The research team then used a piece of equipment called a LI-COR to measure the quantity of CO2 in the air above each plot. They recorded the CO2 levels during the day and night. The comparison from day to night is one way to look at gross primary production and respiration in a system. At night, when there is no light, plants can’t photosynthesize, so the detected CO2 will be from respiration. The levels during the day represent a combination of CO2 absorption by plants and release from respiration.

To assess whether the ecosystem is a carbon sink or source, we need to determine the difference between respiration and gross primary production, or net ecosystem exchange (NEE). A negative NEE means the ecosystem absorbs more CO2 than it emits. A positive NEE means the ecosystem is releasing more CO2 than it is absorbing. In this way, scientists classify an ecosystem as either a carbon sink that is storing carbon or a carbon source that is releasing carbon into the atmosphere.

Featured scientists: Trisha Atwood, Karen Beard, and Jaron Adkins from Utah State University and Bonnie Waring from Imperial College. Written by Andrea Pokrzywinski.

Flesch–Kincaid Reading Grade Level: 8.9

Additional teacher resources related to this Data Nugget:

Check out this website created by teacher Andrea who participated in the research and wrote this Data Nugget. You will find additional lesson plans, videos, slides, and articles to use in the classroom!

6.7.24

Seagrass survival in a super salty lagoon

A researcher in the Dunton Lab measures seagrasses underwater using a mask, snorkel, and a white PVC quadrat.

The activities are as follows:

Seagrasses are a group of plants that can live completely submerged underwater. They grow in the salty waters along coastal areas. Seagrasses are important because they provide a lot of benefits for other species. Like land plants, seagrasses use sunlight and carbon dioxide to grow and produce oxygen in a process called photosynthesis. The oxygen is then used by other organisms, such as animals, for respiration. Other organisms use seagrasses for food and habitat. Seagrass roots hold sediments in place, creating a more stable ocean bottom. In addition, the presence of seagrasses in coastal areas slows down waves and absorbs some of the energy, protecting shorelines.

Unfortunately, seagrasses are disappearing worldwide. Some reasons include damage from boats, disease, environmental changes, and storms. Seagrasses are sensitive to changes in their environment because they have particular conditions that they prefer. Temperature and light levels control how fast the plants can grow while salinity levels can limit their growth. Therefore, it is important to understand how these conditions are changing so that we can predict how seagrass communities might change as well.

Ken is a plant ecologist who has been monitoring seagrasses in southern Texas for over 30 years! Because of his long-term monitoring of the seagrasses in this area, Ken noticed that some seagrass species seemed to be in decline. Kyle started working with Ken during graduate school and wanted to understand more about what environmental conditions might have caused these changes. 

Manatee grass (Syringodium filiforme) located within the Upper Laguna Madre.

Texas has more seagrasses than almost any other state, and most of these plants are found in a place called Laguna Madre. During his yearly seagrass monitoring, Ken noticed that from 2012 – 2014 one of the common seagrasses, called manatee grass, died at many locations across Laguna Madre. Since then, the seagrass has grown back in some places, but not others. Kyle thought this would be an opportunity to look back at the long-term dataset that Ken has been collecting to see if there are any trends in environmental conditions in years with seagrass declines.

Each year, Ken, Kyle, and other scientists follow the same research protocols to collect data to monitor Laguna Madre meadows. Seagrass sampling takes place 2 – 4 times a year, even in winter! To find the manatee grass density, scientists dig out a 78.5 cm2 circular section (10 cm diameter) of the seagrass bed while snorkeling. They then bring samples back to the lab and count the number of seagrasses. While they are in the field, they also measure environmental conditions, like water temperature and salinity. A sensor is left in the meadow that continuously measures the amount of light that reaches the depth of the seagrass.

Kyle used data from this long-term monitoring to investigate his question about how environmental conditions may have impacted manatee grass. For each variable, he calculated the average across the sampling dates to obtain one value for that year. He wanted to compare manatee grass density with salinity, water temperature, and light levels that reach manatee grass. He thought there could be trends in environmental conditions in the years that manatee grass had low or high densities.

Featured scientists: Kyle Capistrant-Fossa (he/him) & Ken Dunton (he/him) from the U-Texas at Austin

Flesch–Kincaid Reading Grade Level 9.8

Additional teacher resources related to this Data Nugget:

There is another Data Nugget that looks at these seagrass meadows! Follow Megan and Kevin as they look at how photosynthesis can be monitored through the sound of bubbles and the acoustic data they produce.

Follow this link for more information on the Texas Seagrass Monitoring Program, including additional datasets to examine with students.

There are articles in peer-reviewed scientific journals related to this research, including:

National Park Service information about the Gulf Coast Inventory and Monitoring.

Texas Parks and Wildlife information on seagrass:

4.24.24

Eavesdropping on the ocean

Scientists heading out to the proposed wind energy site.

The activities are as follows:

Most of our energy in the United States comes from fossil fuels like natural gas, coal, and oil. These energy sources are efficient, but they release greenhouse gases into the atmosphere when burned. They are also non-renewable, meaning there is a limited supply. Renewable energy options collect energy from sources that are naturally replenished, such as sunshine, wind, and even ocean waves. By using renewable energy sources, we can fuel our lives without depleting fossil fuel supplies.

Windmills have been used by humans to capture energy from the wind long before electricity was discovered. Historically, they were used to pump water and grind grains to make flour. Today, they are used to generate electricity that can be used in your home. Most of these modern windmills (also known as turbines) are located on land, but researchers and engineers are exploring a new type of site – the ocean.

Offshore wind energy sites in the U.S. are usually at least 20 miles from land. Winds that blow over the ocean are much more consistent than on land, making offshore energy more reliable. In addition, land that can be used for windmills is limited, especially in areas where there are already a lot of people. Offshore wind energy could be a solution where there are a lot of people living along the coast.

Scientists attach a weight to the line and wait to get into position to deploy a drifting recorder

Careful planning goes into these large-scale projects. Before any construction begins, scientists want to make sure the benefits outweigh the costs. One topic of concern is marine mammals. Many marine mammals, like whales, are federally protected, and some are endangered species. Scientists are worried that the construction of offshore windmills could impact the whales that live or migrate through the designated wind energy areas.

Whales use sound transmitted through the water to survive. Just like many animals on land, they use sound to communicate, navigate, find food, and avoid predators or other threats. Noise from construction activities could cause whales to avoid the area. They may need to find a new area to find food, rest, or find mates. Whales typically migrate, so loud noises could also interfere with their migration route.

Shannon is an acoustic ecologist, meaning she uses sound and how it is transmitted to learn more about organisms and their environment. She works with Desray, who is a research biologist specializing in marine mammals. Together, they are leading a large project to collect sound data to assess the risks of a proposed offshore wind energy site off the coast of central California. One specific goal they have is to see whether it is possible to identify the best time of year to build the wind energy platforms with the least disturbance to marine mammals. To do this, they had to learn more about when whales are using and traveling through the area of the proposed site.

Acoustic ecology is a way to learn more about whales and their behavior through sound, which is important because visual detections are limited and take a lot of time out at sea. Instead, scientists can analyze acoustic data to detect which species are present. Each species makes different sounds with unique patterns, and by listening, we can identify which species are in the area. 

Shannon Rankin and Anne Simonis let out the line with the acoustic recorder and surface floats.

Shannon and a large team of supporting scientists worked together to design floating acoustic recorders. They partnered with Desray to deploy them in the proposed offshore wind energy area. Once the recorders are launched, the team uses satellite location to follow the movement of the recorders from shore. They let the recorders drift in the open ocean for several days before they board a large research boat and pick them up again. While the recorders are drifting, they are continuously recording the ocean sounds below. These drifting recorders cover a larger spatial area, for a longer time, than other types of passive acoustic monitoring methods. The team launched the acoustic recorders in different seasons to learn which whale species are using the proposed site throughout the year and to assess what time of year would have the lowest whale presence near the construction site.

Featured scientists: Shannon Rankin from the NOAA Southwest Acoustic Ecology Lab and Desray Reeb from the Bureau of Ocean Energy Management

Flesch–Kincaid Reading Grade Level 9.4

Additional teacher resources related to this Data Nugget:

  • The NOAA team members on this project have put together a blog series, called “Sound Bytes,” to share the stories and impacts of the ADRIFT research highlighted in this activity. This blog series features many perspectives showcasing how underwater sound, in the form of acoustic data, can be used to learn more about marine mammals.
  • Students can learn more about how acoustic data is analyzed and what it looks like visually by checking out the Ocean Voices project on Zooniverse. Here they can participate in a guided introduction to humpback whale and ship sounds from drifting acoustic recorders and help scientists classify sounds on the recordings.
  • These data were collected as part of the ADRIFT project, led by the Southwest Acoustic Ecology Lab run by the National Oceanic and Atmospheric Administration and the Bureau of Ocean Energy Management.
  • NOAA has a wide variety of lesson plans that you could use to supplement this activity. Here is a set of activities for elementary, middle, and high school on bioacoustics.
  • Lesson on bioacoustics by Seagrant and Woods Hole Oceanographic Institute.
  • For more lessons and activities about wind energy, check out the K-12 teaching materials by the Office of Energy and Renewable Energy.
  • A collection of videos that show the spectrograms and audio recordings for various marine mammals that you could share with students.
  • There is an extensive PowerPoint that has additional information about the ADRIFT acoustics project and other research being done.
Video of a drifting acoustic recorder launch. Turn on subtitles for information about the process.

This study was funded in part by the U.S. Department of the Interior, Bureau of Ocean Energy Management through Interagency Agreement M20PG00013 with the U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service (NMFS), Southwest Fisheries Science Center (SWFSC).

11.17.23

The prairie burns with desire

Stuart showing an Echinacea flower setting seed.

The activities are as follows:

Fire plays a crucial role for prairie habitats across North America. Native Americans have long observed that lush and green pastures grow after a wildfire. In many areas, it is part of current and historical native culture to imitate this natural process by deliberately burning the prairie in a controlled way. This land management practice has many benefits, such as helping native grasses form seeds, thinning out plants, and enhancing habitat for prairie animals. By using controlled fires to cultivate these areas, Native Americans increase the availability of food and connect to the environment and their cultural traditions.

Some land management agencies plan prescribed burns to increase the health of prairie ecosystems. However, fire is still suppressed in many North American prairies due to the possible damage to human development. In these areas, scientists have observed that fire suppression contributes to local plant species extinctions, but we do not know why.

Stuart is a scientist interested in how fire can help prairie plants. In the late 1990s, Stuart was in central Minnesota searching for prairie plants in the Echinacea genus. The prairie was ablaze with flowers, so he had no difficulty finding plenty of plants. He tagged each plant so that he could study them again in the future. However, when he returned the following year, the field had almost no flowers! He kept returning to this same field. A few years later he found the site was again filled with flowers. That year there had been a prairie fire. Visually seeing the impacts of fire on the landscape is a memory he will not forget.

Stuart became interested in learning more about how fire affects the reproduction of native prairie plants. He knew that Echinacea plants grow in many places, but they have a hard time making seeds. This genus cannot self-pollinate, meaning they must be fertilized with pollen from a genetically different plant. Echinacea plants are also dependent on insects, such as bees, to pollinate them.

Echinacea flower

In 1996, a research team started collecting data on Echinacea plants in a large research site in Minnesota. This prairie site had a schedule for prescribed burns, or controlled fires that are started by experts to manage the land. These burns would happen every 4-6 years during the spring.

The team established a set of plot locations that they visited each summer. They searched for and mapped the location of all flowering Echinacea plants within these plots. They took measurements on each Echinacea plant – whether it was flowering, and the distance to its second closest Echinacea neighbor.

Stuart decided to take a new look at this long-term dataset. He had two ideas for how fire might be helping Echinacea plants. First, fire might help all the plants get on the same schedule and make flowers at the same time. This synchrony, or flowering at the same time, could help pollen get from one flower to another. Second, fire might remove competing plants from the area, opening up bare ground for new seeds to establish. This would allow Echinacea plants to be closer to one another, again making it easier for pollen to move between flowers.

With these data, Stuart could compare years with and without prescribed burns to see whether fire helped Echinacea flowering. To look at whether fire decreased the space between blooming Echinacea plants, he looked at the distance between a focal plant and its second-closest neighbor. To see whether fire increased the synchrony of flowering, Stuart used the data to calculate the proportion of Echinacea plants that were in bloom during the summer sampling period.

Featured scientist: Stuart Wagenius from the Chicago Botanic Gardens Written by: Harrison Aakre

Flesch–Kincaid Reading Grade Level = 8.6

Additional teacher resources related to this Data Nugget:

More information about the Echinacea project, based in Minnesota. There are additional datasets to explore, blog posts from the field, identification guides, and pictures of the experiments.

Article to learn about cultural perspectives that are traditionally not represented in textbooks. Native Americans have, and continue to incorporate ecology, observations, and making sense of patterns for millennia.

For more information about indigenous knowledges, or traditional ecological knowledge, check out the following websites:

Published journal article about this research. Wagenius, S. et al. 2020. Fire synchronizes flowering and boosts reproduction in a widespread but declining prairie species. Proceedings of the National Academy of Sciences.

9.27.23

Which tundra plants will win the climate change race?

Some arctic Tundra plant species monitored in this experiment.
Arctic tundra plant species monitored in this experiment.

The activities are as follows:

The Arctic, the northernmost region of our planet, is home to a unique biome known as tundra. While you might think of the arctic tundra as a blanket of snow and polar bears, this vast landscape supports a diversity of unique plant and animal species. The tundra is an area without trees that supports many species of plants, mammals, birds, insects, and microbes. 

Arctic environments present many challenges to plants. Temperatures only creep above freezing for about three months each year. This short arctic summer means that the species that live there only have a brief period to grow and reproduce. From mid-May to the end of July the sun doesn’t set, so there’s plenty of light available. Plants need this light for photosynthesis to make sugars for food. 

Even when there is light, plants need to wait until the snow has melted and the soil has thawed enough for them to grow. Tundra plants have short roots since they can’t grow through frozen ground. These roots try to get nutrients the plant needs from the soil. But with the soil so cold, decomposition is very slow. This means that microbes cannot easily convert dead plant material into nutrients that plants need such as nitrogen and phosphorus. For this reason, the growth of tundra plants is usually limited by nutrients.

Climate change is altering the arctic environment. With warmer seasons and fewer days with snow covering the ground, soils are thawing more deeply and becoming more nutrient-rich. With more nutrients available, some plant species may be able to outcompete other species by growing taller and making more leaves than other plant species. This means that climate change may alter the whole ecosystem game in the tundra. Instead of nutrients limiting plant growth, it may shift to a game of competition between plants reaching for light.

Gus (left) and Jim (right) set up a weather station to monitor air temperature and humidity on the tundra.
Gus (left) and Jim (right) set up a weather station to monitor air temperature and humidity on the tundra.

To simulate the environmental conditions, we can look at long-term data from two scientists, Gus and Terry, who started working at the Toolik Field Station in northern Alaska in the 1970s. They conducted a series of experiments and learned that two nutrients, nitrogen and phosphorus, limited plant growth in the tundra. Then, in 1981, they set up a new experiment where they added both nutrients to experimental plots every year. Gus and Terry compared plant growth between these fertilized plots and control plots that were not fertilized. They wanted to figure out how each plant species would respond to more nutrients over the long term and what would happen to the plant community to see if some species would outcompete others in the fertilized conditions. This experiment is one way to mimic future conditions and test hypotheses about what we might expect to see.

The fertilizer was added every year in early June after the snow melted off the plots. Beginning in 1983, other scientists, such as Laura and Ruby, began to sample these plots. They dug out small 20-centimeter by 20-centimeter samples of tundra and brought them back to the nearby Toolik Field Station. In the lab, the tundra sample was separated into individual plant species and “plucked” to sort by different plant tissue types: leaves, stems, and roots. Then these plants were dried and weighed to determine the biomass (mass of living tissue) of each species in the sample. The fertilized and non-fertilized plots were sampled and plucked six times between 1983 and 2015. This means that many of the scientists who sampled the plots in 2015 had not yet been born when the experiment started in 1981!

Featured scientists: Gus Shaver (he/him), Jim Laundre (he/him), Laura Gough (she/her), and Ruby An (she/her) from Toolik Field Station, Arctic Long-term Ecological Research Site

Flesch–Kincaid Reading Grade Level = 8.6

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9.15.23

A difficult drought

A field of switchgrass studied by biofuels researchers.

The activities are as follows:

Most people use fossil fuels like natural gas, coal, and oil daily. We use them to generate much of the energy that gets us from place to place, power our homes, and more. Fossil fuels are very efficient at producing energy, but they also come with negative consequences. For example, when burned, they release greenhouse gases like carbon dioxide into our atmosphere. The right balance of greenhouse gasses is needed to keep our planet warm enough to live on. However, because we have burned so many fossil fuels, the earth has gotten too hot too fast, resulting in climate change. Scientists are looking for other ways to fuel our lives with less damage to our environment.

Substituting fossil fuels with biofuels is one of these options. Biofuels are fuels made from plants. Unlike fossil fuels, which take millions of years to form, biofuels are renewable. They are made from plants grown and harvested every few years. Using biofuels instead of fossil fuels can be better for our environment because they do not release ancient carbon like burning fossil fuels does. In addition, the plants made into biofuels take in carbon dioxide from the atmosphere as they grow.

To become biofuels, plants need to go through a series of chemical and physical processes. The sugar stored in plant cells must undergo fermentation. In this process, microorganisms, like yeast, transform the sugars into ethanol that can be used for fuels. Trey is a scientist at the Great Lakes Bioenergy Center. He is interested in seeing how yeast’s ability to transform sugar into fuel is affected by environmental conditions in fields, such as temperature and rainfall.

When there was a major drought in 2012, Trey used the opportunity to study the impacts of drought. The growing season had very high temperatures and very low rainfall. These conditions make it more difficult for plants to grow, including switchgrass, a prairie grass being studied as a potential biofuel source.

Trey knew that drought affects the amount and quality of switchgrass that can be harvested. He wanted to find out if drought also had effects on the ability of yeast to transform the plants’ sugars into ethanol. Stress from droughts is known to cause a build-up of compounds in plant cells that help them survive during drought. Trey thought that these extra compounds might harm the yeast or make it difficult for the yeast to break down the sugars during the fermentation process. Trey and his team predicted that if they fed yeast a sample of switchgrass grown during the 2012 drought, the yeast would struggle to ferment its sugars and produce fewer biofuels as a result.  

To test their idea, the team studied two different sets of switchgrass samples that were grown and collected in Wisconsin. One set of switchgrass was grown in 2010 under normal conditions. The other set was grown during the 2012 drought. The team introduced the two samples to yeast in a controlled setting and performed four fermentation tests for each set of switchgrass. They recorded the amount of ethanol produced during each test.

Featured scientists: Trey Sato from the University of Wisconsin-Madison. Written by Marina Kerekes.

Flesch–Kincaid Reading Grade Level = 8.2

Additional teacher resources related to this Data Nugget include:

There are other Data Nuggets that share biofuels research. Search this table for “GLBRC” to find more! Some of the popular activities include:

The Great Lakes Bioenergy Research Center (GLBRC) has many biofuel-related resources available to K16 educators on their webpage.

For activities related specifically to this Data Nugget, see:

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