Lowell Cemetery in Lowell, Massachusetts on May 30, 1868, and May 30, 2005.

It’s not just Daylight Savings Time that came early this year. All around the world, spring seems to be coming sooner than it used to. It hasn’t moved up on the calendar — but many cycles in nature are telling us that spring just can’t wait to be sprung.

Dandelions push through the soil and bloom weeks earlier than they did decades ago. Robins who migrated for the winter are shortening their stays down south. In some places, butterflies usually not seen until July have been flitting about since January. That’s great, right? After all, nearly everyone looks forward to spring’s arrival after a long, cold winter.

Not so fast, say many scientists. A growing body of evidence suggests these shifts in timing are coming about because of climate change. And these changes might spell trouble for the countless species of plants and animals that depend on one another.

Timing is everything

“The timing of life cycles in nature really matters a lot,” says Abe Miller-Rushing, a scientist at the Rocky Mountain Biological Laboratory in Crested Butte, Colo. Miller-Rushing is one of a growing number of scientists investigating how climate change affects the timing of events in nature.

“Many organisms time their life cycles with the seasons,” he says. “Relationships between species could be disrupted as a result of changes in timing.”

Climate change, however, is a long-term phenomenon. To confidently say that climate change affects natural cycles, such as the date when maple trees first unfurl their leaves, scientists need to document what day the event occurs over many years. Then, they need to compare those dates with climate factors such as average temperature or rainfall over long periods of time — ideally decades. Finally, they need to figure out if changes in the timing of natural events are connected to changes in climate patterns.

“One of the big limitations to understanding how climate change affects plants and animals is you need data from a long time, and there just isn’t a lot of that out there,” Miller-Rushing says.So scientists need to be creative in their hunt for data.

Turning to history

Miller-Rushing turned to a long-dead figure in American history and literature for help. Henry David Thoreau, a writer and naturalist who lived in suburban Boston during the mid-1800s, kept detailed diaries of the natural cycles in his surroundings. In these diaries, he recorded the flowering times of hundreds of plants in eastern Massachusetts.

Kids in Arizona inspect plants for hints of early flowering.

D. Amber

To compare Thoreau’s observations with today’s cycles, Miller-Rushing and his colleague at Boston University tracked the first flowering date for 43 of those species during the years 2004, 2005 and 2006.

They found that plants like violets and buttercups are blooming on average seven days earlier than they did in Thoreau’s time. And some species, such as wild blueberries, bloom three weeks earlier than they did 150 years ago.

Seven days might not seem like that much time. But many plants rely on insects to move their pollen from one flower to another — a crucial step in plant reproduction. And some plants only produce flowers for about a week, says Richard Primack, a conservation biologist at Boston University.

“If flowering shifts a week or two earlier and the insects that pollinate it are not coming out, it’s possible that the species won’t be pollinated, and it won’t set fruit,” Primack says.

That’s significant for two reasons. First, when a plant “sets fruit,” it makes the seeds that will become the next generation of plants. If a plant doesn’t set fruit, it doesn’t reproduce.

Second, many birds rely on fruit as a food source — especially in the fall when they are building up their energy stores to migrate south for the winter. If plants aren’t pollinated in the spring, this food resource won’t exist in the fall.

But scientists are still learning how climate change may affect communities of plants and animals. “Right now, we only know the relationships are changing,” Primack says. “Now we’re actively researching the effect these changing relationships will have on species.”

It’s not only wildlife that’s feeling the effects of these shifting cycles, says Christine Rogers. She is a biologist at the University of Massachusetts Amherst who studies how pollen, fungal spores and bacteria in the air affect people. She says kids with allergies might be sniffling and sneezing earlier than ever before.

“We know that the spring seasons are coming earlier, and that means the pollen people are allergic to is coming out earlier,” she says. “The timing of the allergy season is shifting to an earlier time period.

Citizen scientists

Understanding how nature responds to climate change will require monitoring key life cycle events — flowering, the appearance of leaves, the first frog calls of the spring — all around the world. But ecologists can’t be everywhere so they’re turning to non-scientists, sometimes called citizen scientists, for help.

A group of scientists and educators launched an organization last year called the National Phenology Network. “Phenology” is what scientists call the study of the timing of events in nature.

One of the group’s first efforts relies on scientists and non-scientists alike to collect data about plant flowering and leafing every year. The program, called Project BudBurst, collects life cycle data on a variety of common plants from across the United States. People participating in the project — which is open to everyone — record their observations on the Project BudBurst website.

“People don’t have to be plant experts — they just have to look around and see what’s in their neighborhood,” says Jennifer Schwartz, an education consultant with the project. “As we collect this data, we’ll be able to make projections about how plants and communities of plants and animals will respond as the climate changes.”

That data will help scientists predict not only how natural communities may change but also how these changes will affect people, says Jake Weltzin. He’s the executive director of the National Phenology Network.

Weltzin says scientists monitoring lilac flowering in the western United States reported that in years when lilacs bloomed early — before May 20th — wildfires later in the summer and fall tended to be larger and more severe. Lilac blooming, then, could serve as an alarm bell, he says.

“If we had a network of people collecting this information, scientists could use that information to come up with a nationwide tool for predicting fires in the west,” Weltzin says.

Down the road, he says the National Phenology Network plans to coordinate with other monitoring programs, such as the Cornell Laboratory of Ornithology’s Great Backyard Bird Count, the University of Kansas’ Monarch Watch or the National Wildlife Federation’s FrogWatch USA. Closer coordination will help scientists recognize new patterns, such as whether a change in the timing of flowering affects insect population levels.

Improved monitoring is an important step toward predicting how natural communities will respond to climate change, Miller-Rushing says.

“The best way for us to increase our knowledge of how plants and animals are responding to climate change is to increase the amount of data we have,” he says. “That’s why we need citizen scientists to get as much information from as many places on as many species over as long a time period as we can.”

Word Find: Springing Forward

Scientists recently did experiments on several species of freshwater fish to see how they reacted to antidepressants in their water. Normally a bottom-dwelling species, this bass exposed to antidepressants started swimming at the surface, partially out of

When you’re sick, you might take medications to help you fight off infection, lower a fever or clear a stuffy nose. But once those drugs leave your body, chances are they will find their way into nearby lakes, ponds, rivers and streams.

Drugs end up in a body of water because you excrete them in urine. When you flush a toilet, the wastewater travels to a treatment plant. There, bacteria and other material are filtered out and the cleaned water is returned to natural bodies of water. The trouble is, wastewater treatment plants don’t filter out drugs. Some people even flush unused drugs down the toilet, only adding to the problem.

While medications are meant to help a person feel better, they’re not good for wildlife. Over the past several years, scientists have begun to test how common drugs are in freshwater ecosystems. Researchers also are starting to learn more about how medications meant for humans affect the animals that accidentally ingest the drugs.

Recently, several scientists tested how a group of drugs called antidepressants affects freshwater fish. For many people with an illness called depression, antidepressants can be lifesavers. People with depression may feel sad or anxious for extremely long periods of time, lose interest in activities they once enjoyed and have difficulty sleeping or concentrating. Antidepressants help improve these symptoms for some people.

Several years ago, researchers discovered that some species of fish living near wastewater treatment plants had antidepressants in their brains. “Pretty much any water sample in the vicinity of a wastewater treatment plant will test positive for some group of antidepressants,” says chemist Melissa Schultz, of the College of Wooster in Ohio. This finding inspired a number of scientists to learn how these drugs affect fish and other wildlife.

In their experiments, researchers exposed species of fish in a laboratory to different brands of antidepressants. Then, the scientists tested the fishes’ responses to a number of things, such as the cues predators make or the appearance of prey animals.

Some hybrid striped bass exposed to the antidepressant Prozac eventually began hanging vertically in the water — a highly unlikely pose — and stopped eating.

Clemson University’s Institute of Environmental Toxicology

The researchers found that antidepressants affect fish species in numerous ways, from diminishing their response to predators to slowing down their prey-hunting techniques. One unexpected result even showed that a type of antidepressant called fluoxetine acts like estrogen, a primarily female hormone, when in the bodies of adult male fathead minnows.

Fluoxetine, sold under the brand name Prozac, caused these male minnows to produce an egg protein normally made only by females. In addition, males exposed to fluoxetine did not make the bright colors and facial bumps usually used to attract mates. More testing needs to be done to determine whether these changes affect minnows’ ability to mate.

It’s important to keep in mind that in any lake or stream, fish and other organisms aren’t just exposed to antidepressants, Schultz says. Antibiotics, anti-inflammatories, and even caffeine all make their way through water treatment plants and back into the environment. What happens to fish and other animals when they’re exposed to all of these drugs in combination? For now, nobody knows, Schultz says – leaving the door open to many future research questions.

This video shows a hybrid striped bass quickly gobbling up four minnows. Fed only once every three days, the bass tend to become quite aggressive about downing their meals. After being exposed to high concentrations of Prozac, however, some bass took up to two minutes to capture their first minnow and didn’t finish all four with the allotted 25 minutes. Over the nearly month-long experiment, a few bass lost their appetites altogether.

Source: Clemson University’s Institute of Environmental Toxicology

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The human body is regulated by several internal clocks, which control sleeping and eating patterns among other things.

Try this: For an entire day, forget about the clock. Eat when you’re hungry and sleep when you’re tired. What do you think will happen?

You may be surprised to find that your day is much like most other days. You’ll probably get hungry when you normally eat and tired when you normally sleep. Even though you don’t know what time it is, your body does.

These patterns of daily life are called circadian rhythms, and they are more than just habits. Inside our bodies are several clocklike systems that follow a roughly 24-hour cycle. Throughout the day and night, our internal clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

Everyone’s rhythms are unique, which is why you might like to stay up late while your sister always wants to go to bed early. But overall, everyone is programmed to feel tired at night and alert during the day.

Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal clocks. Now, new discoveries are giving scientists insights into how these clocks work.

Learning about our body clocks may help scientists understand why problems arise when we act out of step with our circadian rhythms. For example, traveling across time zones can make people wake up in the middle of the night. Regularly staying up late can make kids do worse on tests and quizzes. And working shifts at night leads to higher rates of heart disease, diabetes and obesity.

“There is a growing sense that when we eat and when we sleep are important parts of how healthy we are,” says Steven Shea, Director of the Sleep Disorders Research Program at Brigham and Women’s Hospital in Boston.

Scientists still aren’t sure why the timing of sleep matters so much, Shea says. But research findings suggest that our circadian rhythms are more important than we give them credit for.

“During the night, we are prepared to sleep,” Shea says. “During the day, we are prepared to eat and move around. If you reverse what you are doing, everything is out of phase. That can have adverse consequences.”

Time warp

One way to learn about how our body clocks tick is to mess them up and see what happens. That’s what neuroscientist Frank Scheer and his colleagues did in a recent study.

The researchers brought 10 people to their lab at Harvard Medical School in Boston. The lab was sort of like a timeless chamber. Rooms were dimly lit. There were no windows and no clocks. It was impossible to know what time it was.

“If you knew it was 4 a.m., you’d think, ‘I must be really tired,’ ” says Scheer, who also works with Shea at Brigham and Women’s Hospital. Removing time cues eliminated these powers of suggestion.

Participants were allowed to sleep only when the scientists said it was OK. The study subjects ate only at designated mealtimes. They were given a precisely calculated number of calories, designed to meet their needs. And they had to finish everything on their plates.

The experiment lasted for 10 days. Participants didn’t know the design of the experiment. In particular, they didn’t know that they were living a 28-hour day instead of the usual 24. With that unusual schedule, they ended up eating and sleeping at all different times of day — and different times of the body clock — over the course of the study.

The most interesting result of the study, Scheer says, involved a hormone called leptin. Hormones are the body’s messenger molecules. Leptin, in particular, sends a fullness message to the brain. As you eat, leptin levels rise until you feel like you’ve eaten enough.

When people in the study slept during the day and ate at night, however, leptin levels dropped. That suggests that people who follow unusual schedules are less likely to feel full after eating.

If given unlimited amounts of food, these people would probably eat more and crave more junk food, the researchers predict. As a result, they could gain weight and develop weight-related health problems, such as diabetes and heart disease. Other studies support that prediction.

Kids don’t often work night shifts. “But some may experience staying up late at night,” Scheer says. That’s OK on special occasions.

But staying up night after night, these studies suggest, could make kids extra hungry and more likely to gain weight. And regularly sleeping too little, Scheer says, may be one cause of the recent surge in childhood obesity.

Eat to sleep

Scheer’s work suggests that our sleeping schedules affect our eating habits. But do our eating schedules influence our sleeping habits?

New research suggests that it works both ways, says Clifford Saper. He’s a neurologist, or a scientist who studies the brain, at Beth Israel Deaconess Medical Center in Boston.

In one recent study, Saper and colleagues investigated a different type of body clock in mice. Like people, mice have more than one internal clock. In the brain, there is the master clock that responds to light and helps determine when we get tired. There are a bunch of minor clocks, too, which reside in the gut, blood vessels and other parts of the body.

The master clock works like “the conductor of a symphony,” Saper says. It’s like the clock at school that determines when classes end and when lunch begins. Everyone sets their watches to this clock. In the body, the secondary clocks follow the lead of the master pacemaker.

Sometimes, however, the master clock gives up control. One example is when mice don’t eat for a long time. If a food source appears when a hungry mouse is normally sleeping, and the mouse happens to wake up in time to find it, this minor food clock wakes the mouse up a couple of hours before that time, night after night.

This ability to change their schedules instantly helps mice survive. If the animals are starving, the food clock ensures that they are awake when food is available, even if it’s an odd time to be up and an odd time to eat. It doesn’t matter whether it’s dark or light outside.

“The amazing thing is that the [food] clock … adjusts to whatever time it finds the food immediately,” Saper says. “It could make a 12-hour time shift overnight.”

The master clock, on the other hand, can only adjust slowly to changes in light.

Saper wanted to know more about this food clock. In his study, he turned off all the internal clocks in a group of mice. Then, he turned the clocks back on, one by one.

His results pinpointed the food clock to a certain part of the mouse’s brain. That’s interesting because the master clock resides in a different part of the brain. Figuring out where the food clock is will help scientists better understand how it works.

Similar studies haven’t been done in people, but human brains are wired much like mouse brains, Saper says. He suspects that people have a food clock, too. If so, his work might eventually help night shift workers learn to reset their circadian rhythms without health problems.

The mouse study might also offer help for people who suffer from jet lag when traveling. Jet lag is the exhaustion and disorientation that comes with crossing many time zones.

The master clock requires a day for every time zone crossed to adjust to the new time. But Saper’s work suggests that people could speed up this process by jump-starting their food clocks. To do this, travelers would need to fast for at least 16 hours before eating breakfast at the normal time they would in their new destinations.

“You could potentially turn on the food clock and adjust to a new time zone very rapidly,” Saper says. For now, he adds, “It’s all speculation.”

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Word Find: Body Clocks

This portrait of Saturn’s rings looks toward the northern side, which is not lit by the sun. Sunlight lights up the rings from below, though, and light not reflected scatters through the rings’ particles, making them glow.

Many students know that to figure out the age of a tree, you count the number of rings that make up its trunk, one ring for each year. But what if you wanted to know the age of the rings that surround the planet Saturn?

It’s a tricky question that scientists have tried to answer for decades. In the late 1970s, the National Aeronautics and Space Administration, or NASA, sent a pair of spacecraft called Voyager 1 and Voyager 2 into outer space. Part of their mission was to fly past Saturn while taking pictures of and collecting data about the planet, then send all this information back to Earth.

Based on the data collected on those missions, scientists first estimated that the rings surrounding Saturn were only 100 million years old. Even though that sounds very old, 100 million years is actually quite young when compared with the solar system, which is 4.6 billion years old.

Looking at the physical characteristics of the particles that make up the rings is partly what helped astronomers determine the age. They reasoned that because the rings appear shiny and reflective, the particles in them, and the rings themselves, were fairly young. The scientists thought that the particles were young because they had not been around long enough for their surfaces to become darkened and less reflective. Things like dust and craters left from collisions with small meteorites can get particles dirty.

But a team of researchers in Colorado thinks Saturn’s rings might be much older, closer to the age of the solar system itself. These researchers used a combination of computer simulations, which mimic events, and data from the Cassini spacecraft, which is currently orbiting Saturn and collecting data.

In the computer simulation, the team estimated the gravitational pull, a force that pulls objects together, between each of the particles making up the rings. Big particles in the rings may pull smaller particles to themselves, where they stick and make one larger particle. In their simulations, the researchers found that the particles making up Saturn’s rings stick together in clumps and are not uniformly distributed, as previously thought.

The formation of new, larger ring particles from older, smaller ones could erase any surface darkening from previous collisions with meteorites, the researchers reasoned. They suggest the particles may look younger than they really are because they constantly clump together, possibly burying the cratered, dusty surface of the older particles beneath the surface of the new clumped particles.

Because of these clumped particles, scientists may have also underestimated the mass of the rings. Previously, astronomers calculated the mass of the rings by measuring how much starlight their particles blocked. The thinking was that the amount of blocked starlight could tell the amount of material in the rings. The more starlight was blocked, the more mass was present in the rings, the scientists reasoned.

But the older calculation assumed the particles were fairly evenly spread out in the rings. These newer data suggest the particles in the rings are clumped together with large empty spaces between them. In that arrangement, more light passes through than if the same mass of particles was spread evenly, as previously thought. This new understanding suggests Saturn’s rings contain much more mass than scientists first estimated.

Taken together, the findings raise new questions about the estimated age of Saturn’s rings, says Mark Lewis, a computer scientist at Trinity University in San Antonio, Texas. But until astronomers know more about what material the ring particles are made of, and details about how they clump together, the age of Saturn’s rings will remain an astronomical puzzle.

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