10.6.26

Gone fishin’ for survival

A coastal cutthroat trout in a holding tank.

The activities are as follows:

Climate change is affecting our world in many ways. Globally, we are experiencing more droughts and wildfires, shifting seasons, and rising sea levels. Species are responding as well. Some can shift their ranges to follow cooler temperatures. But what about organisms, like fish, that cannot easily move to a new location?

A group of scientists is studying fish in streams in central Oregon to learn more. The H.J. Andrews Experimental Forest, also called the Andrews, is a long-term research site in the Cascade Mountains of central Oregon. Scientists have been collecting data there for decades! The Andrews is an old-growth temperate rainforest with a dense canopy of trees. These trees block the sun’s heat, keeping the understory and streams below cool.

Ivan and his team electrofishing Mack Creek to sample the trout population.

Ivan is a biologist on this team who studies fish in these streams. Originally from southern Chile, he has spent decades studying ecology in both marine and freshwater environments. Ivan first came to Oregon to study how logging affects stream ecosystems. While working at the Andrews, he noticed that air temperatures in the forest were getting warmer over time. He wondered if the stream temperatures were warming too and whether this change might be affecting the fish that live there. He focused on coastal cutthroat trout living in Mack Creek, a stream within the Andrews.

Ivan started his exploration with data from historical surveys. For many years, scientists, staff, and students at the Andrews have been sampling coastal cutthroat trout in the streams. They collect data on their body size and other health measures. Ivan and his team found data on trout fork lengths, or the distance in millimeters (mm) from the tip of the fish’s snout to the center of its tail, dating back to the 1980s. Ivan used these data to calculate the median fork length of trout measured each year. The median is the middle value when all the trout are ordered from smallest to largest.

Each trout is measured before being released back into the creek.

Ivan also found data on Mack Creek water temperature for the same years as the fish length data. Ivan focused on summer water temperatures because these would be the warmest experienced by the trout each year. He found the highest water temperature recorded each summer day, called daily maximum temperature. He then averaged all the daily maximums for each summer, which gave him one temperature value for each year. This value is the average maximum summer water temperature.

Ivan predicted that he would see stream temperatures go up over time due to climate change impacting the Andrews. He also predicted that trout median fork lengths would be getting shorter over time. He based this idea on the temperature-size rule, a common pattern seen in fish. In warmer temperatures, fish metabolism speeds up, and animals with faster metabolisms often mature at a smaller body size. This would support the idea that climate change was leading to smaller fish in the Andrews.

Featured scientist: Ivan Arismendi from Oregon State University, H.J. Andrews Experimental Forest Long Term Ecological Research Site.

Written by Ryan Herlands (he/him) from Springfield Public Schools and Matthew Retterath (he/him) from Fridley Public Schools

Flesch–Kincaid Reading Grade Level = 9.2

Additional Teacher Resources:

You can learn more about the H.J. Andrews experimental forest here. This site is part of the long-term ecological research (LTER) network.

10.1.26

Bringing the heat

A plot in the experimental treatment after the tarp was removed. The tarp caused the snow to melt faster.

The activities are as follows:

Climate change is causing Earth’s average temperature to rise, but warming is not the only change happening. Climate change can affect many parts of an ecosystem at the same time. For example, in the Rocky Mountains, temperatures are getting warmer, and the climate is also getting drier. This means that summers have more hot and dry periods, while winters are bringing less snow. Warmer temperatures and less snowfall cause the snow to melt earlier in the spring.

Amy and Dylan are two scientists working in the Rocky Mountains. They are studying plant phenology, or seasonal timing of events related to growth and reproduction. Visiting year after year, Amy and Dylan noticed dramatic springtime changes. They were able to observe these differences with their own eyes, before they took a scientific approach.

Dylan in the field. Photo Credit: Kelby Anderson.

To support their observations, they turned to historic long-term datasets. They confirmed three important patterns. First, since the 1970s, plants are flowering earlier. Second, over the same time frame, snow is melting earlier and exposing bare ground. Finally, the date that plants are flowering is strongly related to snowmelt date. This suggests that snowmelt date might be a cause of earlier flowering. However, these datasets were also a collection of observations over time. Observations alone cannot prove snow melt is causing earlier flowering. There are too many factors that are changing at the same time.

To tease apart what is going on, Amy and Dylan needed to design an experiment. A carefully designed experiment can isolate factors that may be affecting a variable while controlling other conditions. Amy and Dylan thought that plants rely on the timing of snowmelt as a cue for their phenology.  

To test their hypothesis, Amy and Dylan set up an experiment that manipulated the timing of snowmelt. They chose a field site in a Rocky Mountain meadow. This site contained a mix of many plant species, and they focused on three: two-lobe larkspur (Delphinium nuttallianum), tall larkspur (D. barbeyi), and Lewis flax (Linum lewisii).

Like the surrounding landscape, the meadow was covered in snow over the winter. Amy and Dylan established 16 plots within the meadow. In the spring of 2025, they placed black tarps on half the plots. The tarp warmed in the sun and melted the snow under it. The tarps are removed as soon as bare ground is visible below the tarp. The snow in these ‘experimental’ plots melted two weeks earlier than the ‘control’ plots without tarps.

Amy and Dylan then tracked the development and flowering of plants in both plots. They recorded the first flowering date of each individual plant. For their data they converted calendar dates to day of year. They started with January 1 as Day 1 and continued to count up by one for each day. They predicted that plants in the experimental plots will flower earlier than plants in the control plots.

Featured scientists: Amy Iler (she/her) and Dylan Simpson (he/him) from the Chicago Botanic Garden

Flesch–Kincaid Reading Grade Level = 8.5

Additional Teacher Resources:

There is an additional Data Nugget, “Flowers chasing spring” about this research.

8.21.26

Flowers chasing spring

Linum lewisii flower

How does a plant know when to make a flower? Their phenology, or seasonal timing of growth and reproduction, can be driven by many things. When the weather warms in the spring, many plants start to make flowers when temperatures are just right. Other plants follow the number of hours with sunlight. In one very particular system, plants might actually be following the timing of snow.

High up in the Rocky Mountains, scientists are studying plants at elevations where snow covers the ground for six months of the year. In the spring, when the ground is still covered in snow. Plants under the snow are unable to sense the temperature of the air or sunlight hours. This means that plants may have to use a different cue, such as the timing of snowmelt, to know when to flower. 

Amy and Dylan are two scientists who love and have spent a lot of time in the Rocky Mountains. While there, they noticed the springs were changing and wanted to document what they were observing. They wondered whether the date of snowmelt was changing over time. If so, were the plants responding by shifting their flower timing?

Dylan and a field technician, Mairin Boshoven, observing plants in the Rocky Mountains.

To answer their question, they looked to the work of two additional scientists. The first is David Inouye, a retired plant ecologist from the University of Maryland. David has been observing flowers at the Rocky Mountain Biological Laboratory for the last 50 years. David and his team measured phenology of 163 plant species across 36 plots in the Rocky Mountains. From early spring through summer, they surveyed their plots every two days, recording every plant species flowering in each plot. They measured first flowering date as the day they observed the first flower for each species. His records show, over time plants have been flowering earlier and earlier each year.

Another scientist, billy barr (who doesn’t capitalize his name), has been living and working at the Rocky Mountain Biological Laboratory since the 1970s. Initially for his own curiosity, billy started recording the weather at the Lab. He then built a weather station outside his cabin. His records have become important to many areas of research at the station. 

These records include billy’s observations for the first date that snow was completely melted in the area, called the date of bare ground. billy used Julian dates, which start with January 1 as Day 1 and continue to count up by one for each day. And just like David noticed plants are flowering earlier than they used to, billy noticed that snow has been melting earlier than it used to. 

Hearing about these changes in flowering date and snowmelt timing, Amy and Dylan wanted to know if changes in snowmelt timing itself could explain changes in flower timing. They thought that snowmelt triggers plant growth by exposing the ground to light, warmth, and soil moisture from melting snow. If plants start to grow earlier, they thought they will also flower earlier. This led them to predict that years with earlier snowmelt would have earlier flowering. Fortunately, David’s and billy barr’s datasets already include all the information needed to test this hypothesis! All they had to do was bring the two datasets together in a new way. They started with one species of plant with a purple flower, Linum lewisii.

Featured scientists: Amy Iler (she/her) and Dylan Simpson (he/him) from the Chicago Botanic Garden

Flesch–Kincaid Reading Grade Level = 8.6

Additional Teacher Resources:

There is an additional Data Nugget, “Bringing the heat” about this research.

7.12.26

Turning up the heat

Tall goldenrod plants flowering in one of the ambient condition plots.

The activities are as follows:

Éste Data Nugget también está disponible en Español:

As you step into a warm greenhouse, you can feel how the glass has captured the sun’s heat inside. Now imagine that same warmth spreading across the entire planet due to increased greenhouse gas emissions. Climate scientists predict that by the year 2100, Earth’s average temperature could increase by as much as 3°C because of climate change. That might sound small, but even a few degrees matter a lot.

At the Kellogg Biological Station in southwest Michigan, a group of researchers wanted to know how climate warming will affect plant communities. To find out, they created what they call “mini time machines” using open-top chambers. These chambers are clear, hexagonal-shaped structures that trap heat and make the air inside warmer – just like a greenhouse. The chambers still allow for natural levels of precipitation, air flow, and insects to enter through their open tops. By comparing plant communities grown in these warmed conditionswith chambers, to ambient conditions without the chambers, scientists can see how rising temperatures might impact the plants in the future. Understanding these changes can help us prepare for a future where the climate is different from what we know today.

A scientist collecting data outside an open-top chamber.

The scientists working in the open-top chambers were at multiple stages in their careers. Moriah is a graduate student who became fascinated with plants when she first learned how to identify different species. Instead of looking at plants as all one patch of green, she could then notice all the diversity and the different roles they play in an ecosystem. Mark is a lab technician working with Moriah. He is interested in how plants will respond to warmer climates because it gives a glimpse of the world his grandchildren will see.

When Moriah and Mark started, they were joined by a few other scientists: Kara, another graduate student, and Emily, an undergraduate student. The open-top chambers had already been out in the field for five years. The field was growing with a diverse mix of plants common in the area. Together, they observed that plants growing in the warmed conditions inside the chambers seemed to be taller than those growing in the ambient conditions outside the chambers.

To collect some data to back up their observation, the team began with one species, tall goldenrod. This is a wildflower species with a bright yellow flower, and it is one of the most common species at this location. They wanted to see how goldenrod growth differed in warmed and ambient conditions. When temperatures rise, some plants grow faster and taller to compete for sunlight, but this takes a lot of energy. That means plants have less energy for survival, making seeds, or defending against herbivores, like insects. The researchers predicted that goldenrod inside the chambers would be taller, but would also have fewer stems and plants because they were putting their energy into growing tall instead of making more plants.

Open-topped chambers at the Kellogg Biological Station.

To test their ideas, the team measured goldenrod height with meter sticks and counted the number of goldenrod stems in each plot, called abundance. Their experiment had 30 plots. Half of the plots had open-top chambers, and half did not. That gave them 15 replicates of each treatment. Each plot is 1 meter x 1 meter. 

Featured Scientists: Mark Hammond (he/him), Moriah Young (she/hers), Kara Dobson (she/hers), and Emily Parker (she/hers) from the Kellogg Biological Station Long Term Ecological Research Program

Flesch–Kincaid Reading Grade Level = 9.3

Additional Resources:

  • The group of researchers featured in this activity work together at the Kellogg Biological Station, part of Michigan State University. Their lab is called the Spatial and Community Ecology Lab (SpaCE Lab). To learn more about their lab and work, students can visit their website or check out the Scientist Profiles associated with this activity.
  • Trevor Grabill produced a woodblock printed piece featuring the open-topped chamber experiment, titled What if it’s beautiful?. Along with the piece, they also produced a Zine that includes testimonials by the artist and scientists.
3.9.26

What wakes the squirrels?

An arctic ground squirrel checking out the scientists from inside a trap
An arctic ground squirrel checking out the scientists from inside a trap. Photo by Rachel Rigenhagen.

The activities are as follows:

The Arctic is home to a unique biome, known as tundra. Found at Earth’s northernmost region, the tundra ecosystem is defined by frozen land. Permafrost is a thick underground layer of organic matter, soil, rock, and ice that has been frozen for at least two full years. Each summer as the temperature warms, a thin upper layer of frozen soil thaws, refreezing again the following winter.

Although the tundra might be far away from where most people live, it is connected to the entire globe through the atmosphere. This means it is affected by climate change, just like other places on Earth. In the tundra, increasing temperatures are causing snow to melt and the top layer of permafrost to thaw earlier each year.

Arctic ground squirrels, also called siksik (pronounced shrick-shrick) in the Inuktitut language, are an important mammal species that call the tundra home. They hibernate for roughly eight months – the longest of any mammal in the world. As they hibernate, the snow and frozen permafrost insulate their burrows and protect them from severe cold. As the summer months approach, the squirrels emerge and move above ground. Their mating season begins immediately after hibernation ends. With only four months out of their burrows, they have to maximize their time! 

Cory is a scientist who lives in Colorado but travels to the Arctic to do research at Toolik Field Station. For over 25 years, Cory and his research team have been studying the ground squirrel populations. While at Toolik recently, Cory was surprised to discover that male and female ground squirrels were emerging from hibernation on different schedules. He is worried these mismatches could be due to climate change. 

Austin holding an arctic ground squirrel that has been tagged in front of an Arctic scene background.
Austin, a PhD student in Cory’s lab, releases an arctic ground squirrel that has been tagged. Photo by Rachel Rigenhagen.

This made Cory wonder how ground squirrels know when to come out of their burrow. He suspected that ground squirrels use cues from their environment, such as increasing temperatures, permafrost thaw levels, or the length of time they have been in hibernation. Some of these environmental cues, such as the timing of permafrost thawing, are affected by increased temperatures. Other cues are not affected by temperature, such as the length of time squirrels have been hibernating. If males and females are using different cues, this could be why they are coming out at different times.

To investigate his idea, Cory and his research team turned to data they have been collecting over time. Each year, the research team temporarily captures squirrels. They record each squirrel’s sex, give them a unique ID, and put collars on them before releasing them. The collars can detect light, which is used to know when the squirrels are above ground. For each squirrel, the team records the first date that light was detected after hibernation, called the emergence date. Cory used Julian dates, which start with January 1 as Day 1 and continue to count up by one for each day. 

Cory also looked at the data on snowmelt as a potential environmental cue that the squirrels were using. Each year Cory’s team installs cameras on tall towers so that they can use images to measure daily snow cover. When no snow was detected, they measured this as the snowmelt date. Using these two sources of data, they can look for any patterns in emergence dates and spring snow melt. 

Featured scientist: Cory Williams (he/him) from Colorado State University and Toolik Field Station. Written by Claire Gunder (she/they) and Rachel Rigenhagen (she/her), Avalon School, St. Paul, Minnesota.

Flesch–Kincaid Reading Grade Level = 8.7

10.15.25

Stormy shorelines

A scientist adding water to simulate flooding.

The activities are as follows:

Chevak is a village that sits along the Ningliqvak River in Alaska. The area around the village is a flat coastal wetland, a landscape of winding river channels, marshes, and salty lakes. In the Yup’ik language, this low-lying terrain is called maraq. Here, salt-tolerant grasses and sedges thrive in an environment with brackish water, which is saltier than fresh water, but less salty than sea water. These wetlands serve as nesting grounds for waterfowl during the spring and summer months.

Further upland, the higher ground that sits roughly three meters in elevation is called nunapik, meaning tundra. Brackish water does not usually touch these areas. The tundra has many freshwater lakes and supports a different plant community, rich with forbs, shrubs, and lichen. Because it experiences less flooding, more types of plants can live in the upland tundra, providing important resources for food and medicine.

In recent years, coastal flooding has become more common near Chevak. Protective sea ice melts earlier each year. Storm surges and rising sea levels now push brackish water further inland. These flooding events increase erosion, damage property, and alter the delicate balance of wetland and tundra ecosystems.

Ecologists Karen, Kathy, and Josh began studying the plants around Chevak to better understand how flooding affects these ecosystems. To understand how plant communities at high and low elevations respond to flooding, the scientists designed an experiment at Old Chevak, the original village site abandoned decades ago due to flooding.

Chevak, a village in Alaska.

Working in collaboration with the Chevak community and the Yukon Delta National Wildlife Refuge, they established experimental plots to simulate flooding. The flooded plots were created by pumping in seawater to simulate high-tide flooding. This was repeated 3 times during the summer. Karen, Kathy, and Josh also kept control plots where no brackish water was added. The treatments were repeated at both high and low elevation sites. There were 7 replicates at each location.

At the summer’s end the team collected data on plant growth. They measured the biomass, or weight, of all plants in all of the plots. Karen, Kathy, and Josh grouped the plants into 4 groups. Graminoids, which include grasses and sedges, are the dominant plant group of the maraq. They typically grow well in flooded wetland areas. Forbs are broadleaf herbs, like salmonberries, that grow well in the nunapik. Shrubs include species such as blueberries, cranberries, and tundra tea. Like forbs, they also grow well in the nunapik. Lichens are plant-like species that form low crusts along the ground and are only found in the higher elevation sites.

Karen, Kathy, and Josh thought that plants from the low elevation sites would be made up of more salt and flood-tolerant species and would therefore be less harmed by frequent floods. On the other hand, high elevation sites would consist mostly of plant species that are not salt or flood-tolerant and would not do well during floods.

Featured scientists: Karen Beard (she/her) of Utah State University, Kathy Kelsey (she/her) of the University of Colorado Denver and Joshua Leffler (he/him) of South Dakota State University. Written by: Andrea Pokrzywinski (she/her).

Flesch–Kincaid Reading Grade Level = 8.9

Additional Resources:

This activity pairs with another Data Nugget, “Salmonberries in our future”, which features this same collaboration, but focuses on one culturally significant type of Arctic plant, salmonberries.

Additional video resources and lesson extensions can be found at the project website “Working Together”, including the following:

  • “Voices from the Land” introduces the collaboration between scientists and Yup’ik community members. They are working together to respect and care for the land. This narrative is told by the students from Bethel and Chevak Alaska. 
  • “Mapping Merbok” describes the questions scientists are researching to document how increased flooding, such as that from Typhoon Merbok, will drive landscape changes.
  • “Warming and Flooding on the Tundra” describes the research scientists are conducting to measure the impact of both warming and flooding on plant communities.
9.20.25

Salmonberries in our future

Picking salmonberries is a cultural tradition for many Alaskans.

The activities are as follows:

In the Yup’ik and Cup’ik Native communities of western Alaska, berry picking is a deeply rooted tradition. Many villages are located more than 500 miles from the nearest road system or grocery store. Fresh fruits and vegetables from other places are flown in by small planes at significant cost. This makes local berries a lifeline for these remote villages.

Salmonberries (also known as cloudberries) are one type of Arctic berry. They are prized for their wonderful taste. Salmonberries are rich in nutrients like vitamin C, antioxidants, and essential minerals. One cup of salmonberries alone can meet a person’s daily vitamin C needs. In addition to humans, these berries provide nutrients to other animals, such as migrating birds, small mammals, and bears.

During berry season, families travel across the land to gather berries, preserve them, and store them for the winter. Families use a vast web of winding rivers to travel by boat to reach their berry picking camps. These western Alaska rivers flow towards the Bering Sea, where freshwater mixes with salty ocean tides.

Rubus chamaemorus, known as salmonberry in western Alaska, ready to be picked.

This mix of saltwater and freshwater shapes the tundra landscape. Tough, salt-tolerant plants, like grasses and sedges, often dominate low-lying areas closest to the sea. Slightly higher ground, just above the reach of the tides, provides a more suitable home for berries. These subtle shifts in water levels play a large role in determining where berries can grow.

Ecologists Karen, Kathy, and Joshua are collaborating with Native communities to learn more about how changes in climate are affecting berry plants. They are studying two major changes already observed under climate change – warming and flooding. Over time, warming and flooding combined could change the entire makeup of plant communities. This will affect whether local families are able to continue their traditions and access this valuable food source.

Alaska’s average temperatures are increasing, more so than other parts of the globe. This warming might help some plants by extending the growing season. With more time and sunlight, salmonberries and other plants may actually grow faster.

Climate change is also expected to increase flooding in some areas of coastal Alaska. Storms are already becoming stronger and more frequent, pushing seawater farther inland. Because of this, flooding events are increasing in frequency. Rising sea levels and storm surges may kill salmonberry plants because these plants are not adapted to having their roots submerged in salty water.

To tease apart the effects of warming and flooding, Karen, Kathy, and Joshua designed a field experiment to simulate climate change. They built clear plastic structures, called open-topped chambers, to trap heat and raise the temperature by about 2°C. These chambers can be thought of as mini time machines, creating small areas that have the expected temperatures of the coming decades. Next, they created flooded plots using brackish, or slightly salty, water that they collected where the fresh river water meets the sea. They used this water to simulate flooding events in the plots. In the end, their experiment had four different types of plots: (1) Control plots with no warming or flooding, (2) plots that were warmed, (3) plots that were flooded, and (4) plots that were both warmed and flooded. 

They let these treatments run the full growing season. After that time, the team collected data on salmonberry growth. Karen, Kathy, and Joshua measured both the height and biomass of salmonberry plants in all of the plots. These two measures are good estimates of how many berries the plants will produce – the larger the plant, the more berries it can make. They were very precise in their measurements; in a place where food and traditions are tied to the land, every berry matters.

Note: Cloudberries (Rubus chamaemorus) are regionally known as “salmonberries” in western Alaska, and “Naunrat”, “Atsaq/Atsisaq”, or “Atsalugpiaq” in Yup’ik and Cup’ik. In southeast Alaska, a related but different species, Rubus spectabilis, produces berries that are known as salmonberry in that region. In this activity, we will be referencing Rubus chamaemorus.

Featured scientists: Karen Beard (she/her) of Utah State University, Kathy Kelsey (she/her) of the University of Colorado Denver, and Joshua Leffler (he/him) of South Dakota State University. Written by: Andrea Pokrzywinski (she/her).

Flesch–Kincaid Reading Grade Level = 5.7

Additional Resources:

This activity pairs with another Data Nugget, “Stormy shorelines,” which features this same collaboration but expands to additional plant groups in tundra and coastal habitats. 

These two videos were filmed with scientists during the field research and will give students background information on the research efforts conducted in Chevak, Alaska.

Additional video resources and lesson extensions can be found at the project website “Working Together”, including the following:

  • “Voices from the Land” introduces the collaboration between scientists and Yup’ik community members. They are working together to respect and care for the land. This narrative is told by the students from Bethel and Chevak Alaska. 
7.5.25

Catching fish with sound

Mei next to the research vessel, Endeavor

The activities are as follows:

In our ocean, the connections between the environment and marine organisms are intricate and complex. The watery surroundings connect each level of the food web – including marine mammals, large fish, schooling fish, phytoplankton, and more. Climate change is causing our ocean to become warmer, and organisms are already starting to respond. When ocean waters change, the effects cascade through different levels of the food web. In order to understand how marine organisms, and their interactions, are affected by changing climate, we need accurate measurements that tell us what populations are like today and continue monitoring into the future.
As a biological oceanographer, Mei’s research focuses on organisms in the middle of marine food webs. These are the small schooling fish, like anchovies and herring, that consume other organisms, but are also vulnerable to predation. Growing up in Japan, the ocean was always a part of Mei’s life through hobbies such as swimming, fishing, and also from knowing the cultural importance of eating seafood and learning to prepare for tsunamis. She was first introduced to ocean science through a local fisher who had an oyster farm near her hometown. Since then, she has pursued her career as an oceanographer across three different countries – Japan, Canada, and the United States – both in academia and industry.

Mei now does research as part of a Long-Term Ecological Research project out of Massachusetts. This means that Mei is part of a scientist team working together to study long-term patterns in the ocean.
Looking at data over time allows Mei and others to better identify and understand the consequences of climate change. This information Mei next to the research vessel, Endeavor will help fishers and fisheries managers make decisions and prepare for the future.

Mei testing equipment before a research cruise

In August 2023, Mei went to sea on one of the project’s research cruises. She wanted to take a closer look at one of the fastest-warming ocean areas and richest fisheries in the world – the continental shelf of the Northeast U.S. She boarded a large research ship for 6 days with a team of 14 other scientists who specialize in different areas of oceanographic research. To more accurately collect these data, Mei used sound! Echosounders bounce sound off marine organisms, such as fish. This tool is similar to fish finders that are used by most fishing boats. However, the technology used by Mei is more sensitive and provides more detailed data.
The amount of sound that comes back to the ship after bouncing off fish or anything in the water is called volume backscattering strength, and is measured in decibels (dB). The intensity of what comes back can serve as a measure of fish abundance. If there are more fish, the number becomes larger (less negative).
While the echosounder is operating, other members of the research team measure water temperature and other parameters from the surface to near the bottom. Temperature is measured in degrees Celsius (ºC), and depth is recorded in meters (m). Mei wanted to use these data to give her a snapshot in time of where fish are located.

Featured scientist: Mei Sato (she/her) from Woods Hole Oceanographic Institution and
Northeast U.S. Shelf LTER (NES-LTER)

Flesch–Kincaid Reading Grade Level = 9.8

5.30.25

CO2 and trees, too much of a good thing?

The activities are as follows:

Kristina conducting the tree survey, measuring the size of a tree, which will later be used to calculate the mass of carbon in that tree.

The amount of carbon dioxide (CO2) in the atmosphere has steadily increased since the start of the Industrial Revolution in 1750. This extra CO2 traps heat like a blanket, causing the global climate to warm. The resulting climate change effect is known and widely accepted in science. While scientists are certain that climate change is happening, they still have many questions about its impacts.

For example, scientists today are exploring whether climate change will help or hurt trees and forests. Many scientists think that elevated CO2 in the atmosphere can actually help trees. We can see why in the formula for photosynthesis:

6𝐶𝑂2+6𝐻2𝑂+𝐸𝑛𝑒𝑟𝑔𝑦→𝐶6𝐻12𝑂6 +6𝑂2

Carbon Dioxide + Water + Energy (sunlight) → Glucose + Oxygen

If you add more CO2 to the atmosphere, trees will have more resources for photosynthesis and can make more glucose. Glucose is food for the trees. Trees can use their glucose for growth, using it to make wood. However, trees sometimes have to put glucose towards other things. Just like us, plants break down glucose for energy through cellular respiration:

C6𝐻12𝑂6 +62→ 6𝐶𝑂2+6𝐻2𝑂+𝐸𝑛𝑒𝑟𝑔𝑦
Glucose + Oxygen → Carbon Dioxide + Water + Energy (ATP)

Two large trees stand in the experimental plot after a survey. The tree to the right has been banded to measure its growth.

Trees need energy for everyday functioning, or to respond to stress. Under climate change, trees might experience more stress. Stress for trees might increase if summer temperatures get too hot, or they don’t have enough water. More stress means more respiration and less growth. Or, even worse, the trees could die. Dead trees can’t photosynthesize, and they also decompose, which releases CO2 into the atmosphere
as microbes break down wood and other materials.

Kristina and Luca are scientists looking at the effects of climate change on trees. They wanted to test whether climate change was benefitting or hurting trees. They set out to find some data that would allow them to test these alternative hypotheses.

A dead ash tree stands in the experimental plot after a survey. The carbon in this tree
will return to the atmosphere through decomposition.

Kristina runs a tree census in a forest at the Smithsonian Conservation Biology Center in Virginia. Since 2008, she and many other scientists have surveyed every tree in their 26-hectare plot. Every five years, they count up how many trees are alive, how much they’ve grown, and how many have died. Luca joined Kristina’s lab in 2022. He and Kristina worked together with many other scientists to collect and process data on tree growth and mortality in 2023.

They used this growth and mortality data for individual trees to calculate levels of carbon gained and lost by the whole forest. The amount of carbon used for growth across the whole forest was measured as the mass of carbon gained. They also calculated the weight of the trees that died, which was measured as the mass of carbon lost. Both of these measurements were calculated in megagrams (Mg, that’s one million grams) of carbon (C) per hectare (ha) of forest per year (yr), or (MgC/ha/yr). The difference between these
two values is the change in carbon. This value gives the balance between carbon gained and lost. A positive value means there is more carbon being taken in by the forest than lost, and a negative value means that more carbon is being lost back to the atmosphere.

Featured scientists: Kristina J. Anderson-Teixeira (she/her) & Luca Morreale (he/him) at Smithsonian’s National Zoo & Conservation Biology Institute. Written by Ryan Helcoski

Flesch–Kincaid Reading Grade Level = 7.8

1.20.25

Microbes facing tough times

Jennifer sampling soil before the shelters were set up. Here you can see the control (left) and carbon addition (right) plots.

The activities are as follows:

As the climate changes, Michigan is expected to experience more drought. Droughts are periods of low rainfall when water becomes limiting to organisms. This is a challenge for our agricultural food system. Farmers in Michigan will be planting crops into conditions that make it harder for corn, soybean, and wheat to grow and survive.

Scientists are looking into how crop interactions with other organisms may help. Microbes are microscopic organisms that live in soils everywhere. Some microbes can help crops get through time times. These beneficial microbes are called mutualists. They give plants nutrients and water in exchange for carbon from the plant. Microbes use the carbon they get from plants as food. If plants are stressed and don’t have any carbon to give, microbes get carbon from dead plant material in the soil.

Jennifer is a biologist studying the role of microbes in agriculture. She has always been interested in a career that would help people. As a student, Jennifer thought she would have a career in politics. Along the way, she learned that a career in science is a great way to study questions that may lead to solutions for the challenges we are facing today. Jennifer was drawn to the Kellogg Biological Station, where she joined a team of scientists studying the impacts of climate change and drought on agriculture.

Jennifer and other scientists set out to test ways that we can give mutualists in the soil a boost. She thought, perhaps if we were to give microbes more food, they would be less stressed during a drought and would be able to help out crops growing in these stressful conditions.

To test this idea, Jennifer needed to test how well microbes were doing under different carbon and drought conditions. First, she set up treatments in soybean fields to manipulate the amount of carbon in the soil. She set up control plots where she left the soil alone. She also set up carbon treatment plots where dead plant litter was added to the soil to increase the carbon available to microbes.

Next, Jennifer manipulated the availability of water in her plots to test the microbes under stress. To do this, she set up her plots under shelters that kept out rain. The shelters had sprinklers, which were automated to add specific amounts of water to the plots. This design allowed Jennifer to control the watering schedule for each plot. One shelter treatment was a control, where water was added to the plots every week. This is similar to the schedules of local farmers who add water through irrigation. The other shelter treatment was drought, where plots received no water for six weeks. This experiment was replicated 4 times, meaning there were 4 shelters on the control watering schedule and 4 shelters that were under drought conditions.

A view of one of the shelters used in Jennifer’s experiment.

Finally, Jennifer had to measure how the microbes were doing in each treatment. She did this by measuring their enzyme activity. Enzyme activity is a measure of how active the microbes are. The higher the enzyme activity, the happier the microbes are. To measure this, Jennifer collected soil samples from each plot throughout the growing season and took them to the lab to measure enzyme levels in the soil samples. These enzymes are made by microbes when they are active. She then calculated the mean of all her samples for each treatment combination.

Jennifer predicted two things. First, if drought is harmful to microbes, then she would expect to see lower enzyme activity in the drought treatment compared to the irrigated treatment. Second, if adding carbon to the soil is a way to help microbes overcome the challenge of drought, she expected higher enzyme activity in the plots with plant litter added compared to the control treatment. Both of these taken together would indicate that drought is stressful for microbes, but we can help them out by adding resources like plant litter to soils.

Featured scientist: Jennifer Jones (she/her) from the Kellogg Biological Station Long Term Ecological Research Site. Written with Melissa Frost and Liz Schultheis.

Flesch–Kincaid Reading Grade Level = 8.2

Additional teacher resources related to this Data Nugget:

To introduce this Data Nuggets activity, students can watch a talk by Jennifer when she made a classroom visit to share her background and research interests. This video is a great way to introduce students to scientist role models and learn more about what a career in science looks like, as well as get an introduction to the themes in the research.

There is also a video of Jennifer and her scientist colleague, Grant Falvo, out in the field talking about their research under the rainout shelters.

For more information about the rainout shelter experiment, students can watch this short video featuring Jennifer Jones and another scientist on the team, Grant Falvo:

These data are part of the Kellogg Biological Station Long Term Ecological Research Program (KBS LTER). To learn more about the KBS LTER, visit their website.

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