
Scientists study fish behavior during dyeing of the Chicago River for St. Patrick's Day
Every year as part of the city's St. Patrick's Day celebrations, thousands of onlookers clad in green cheer on a boat crew sprinkling orange powder into the Chicago River to turn it a festive shade.
But with the federal government considering sweeping rollbacks to environmental protections, this Saturday many may wonder: How will the bright green water affect the underwater denizens?
Last year, an extensive scientific study of fish behavior in the Chicago River system led by researchers from the Shedd Aquarium, Purdue University and the Illinois-Indiana Sea Grant offered a clue. In mid-March, as researchers studied aquatic activity they found a handful of the over 80 fish they were tracking were in the main branch downtown. On the day of the 2024 St. Patrick's parade, none of the tagged fish rushed to find shelter from their suddenly green surroundings.
'(It) was the first time that we could actually track how individuals behave when the river is dyed green,' said Austin Happel, a research biologist at the Shedd. 'We didn't see changes in what they were doing that day, or even the next couple of days afterward, so it doesn't seem to be causing them to be agitated.'
Since June 2023, the scientists have been following largemouth bass, common carp, bluegill, pumpkinseed, black crappies, walleyes and green sunfish, among others, with tags that ping every minute or so. These signals are picked up by acoustic receivers throughout the 'Wild Mile' in the North Branch, Bubbly Creek in the South Branch and by the Riverwalk downtown, letting the scientists know how the fish respond to habitat restoration initiatives, flooding and sewage overflows, as well as seasonal changes.
St. Patrick's Day celebrations in 2024 gave scientists a peek into the tradition's impact on aquatic life, a matter that has concerned environmentalists since its origins in 1962.
That first year, an oil-based Air Force dye kept the water green for nearly a month, which caused an outcry. A vegetable dye has been used ever since. While its ingredients are not public knowledge, the Illinois Environmental Protection Agency has previously said the dye has no toxic effect.
Green is not the only color the river's main branch has been tinted: It was turned blue in 2016 to celebrate the World Series champion Cubs on the day of the team's victory parade and celebration.
Happel contrasted the unbothered behavior of some of the study's aquatic participants during the river dispersal of dye last year to another event that made the fish they were tracking in Bubbly Creek swim for cover.
Environment | 'You feel like you're king for a day:' How a family dyes the Chicago River green for St. Patrick's Day
Environment | From homebodies to prolific swimmers, researchers track Chicago River fish to find out where they are going and why
Environment | Court finds Trump Tower violated environmental laws and endangered fish in the Chicago River
When the city of Chicago experiences very heavy rainfall, combined rain and untreated wastewater may overflow from sewage pipes and into local waterways. One such overflow happened during massive rains in early July 2023, a month into the study, and caused fish to swim to other areas where sewage had not depleted oxygen levels. If they are unable to leave the presence of a contaminant, the toxins can lead to a fish kill, or sudden death in large numbers in a specific area over a short period of time.
'A lot of our fish were moving long distances as if they were looking for a place to hide,' Happel said. 'So we can contrast those. With the river dyeing, we have yet to see a fish kill associated.'
He hopes some of their tagged subjects will be in the river downtown for the Saturday celebration so the researchers can continue monitoring any possible effects of the dye on aquatic life. It would be ideal if it were the same five fish that were there last time, Happel said, because each fish, like humans, has their own personality and behavioral quirks. But it's unlikely since the scientists can't control where the animals decide to spend their time.
'At least, with the river dyeing, it's always the same event,' he said. The same kind and amount of dye offers a baseline for scientists to understand the fish's response. 'It's harder with the sewage when, each time, it's a different amount.'
Even though vegetable dye may not have a negative impact underwater, environmentalists worry that putting a foreign substance in the river to tint it an unnatural color sends the wrong message about stewardship.
Advocates say the Chicago River is healthier now than it has been in the past 150 years. It is home to all kinds of animals, including migratory birds, beavers and turtles, as well as 80 species of fish — up from fewer than 10 in the 1970s. The system has become a natural resource for local businesses and recreation.
Environmental groups question whether dyeing is appropriate for a waterway that, despite a historical reputation of pollution, has come such a long way. Several advocacy nonprofits, including the Sierra Club Illinois Chapter, Friends of the Chicago River and Openlands, have spoken out against the tradition, arguing that the city must rethink how it interacts with the river as a signal to residents.
For instance, in 2023, what began as a joke on social media became a trend that had people dumping Mountain Dew soda in the river to mess with out-of-towners and convince them it was how Chicago dyes the water. Rogue dyers have been a problem, too, with a few cases of unsanctioned dumping of colorants into the North Branch of the river despite the presence of conservation police patrols.
'If you see one person, say, throw a piece of trash down, you're more likely to throw a piece of trash down — or you're more likely to care less,' Happel said. 'While we like to say that the river has bigger issues to tackle before St. Paddy's Day, the general image of dumping stuff … is not the best image of how to care for the environment.'
adperez@chicagotribune.com
Hashtags

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
a day ago
- Yahoo
Pore no more: US scientists develop real-time defect detection for 3D metal printing
Scientists from the federally funded Argonne National Laboratory in Illinois and the University of Virginia have developed a new approach for detecting defects in metal parts produced by 3D printing. By combining artificial intelligence (AI), X-ray imaging, and thermal imaging, this approach could pave the way for real-time self-correcting systems in the future. 3D printing of metals involves a method called laser powder bed fusion, where you build objects layer by layer by melting metal powder with a laser. However, a big issue in this process is defects, especially keyhole pores, which are tiny holes that form when the laser melts too deeply. These pores weaken the final object, which is a significant concern when printing high-performance parts, such as rocket nozzles or surgical implants. Keyhole pores also pose a significant challenge as they compromise the structural integrity of printed parts. These tiny voids form when excessive laser energy creates deep, narrow holes that trap gas, leading to internal cavities as the metal solidifies. Recurrent microscopic keyhole pores can act as stress concentrators, increasing the risk of cracks or failure under pressure. This is particularly hazardous in critical applications, such as aerospace, automotive and medical devices, where part reliability is crucial. Detecting and preventing keyhole pores is therefore vital in ensuring the performance, safety, and durability of additively manufactured metal components. To help achieve this, researchers developed a method to identify and predict these pores real-time using a combination of thermal imaging, X-ray imaging, and machine learning. This new process utilizes powerful X-rays (from a government laboratory) to capture snapshots of what was happening inside the metal as it was being printed. A camera also recorded thermal images (from the surface) at the same time. Then, a trained AI model was used to teach it how specific surface heat patterns predict pore formation. Once trained, the model could detect when a pore was forming just from the thermal image, with extremely high accuracy and within milliseconds. Thermal cameras are already installed on several 3D printers. However, until now, they couldn't reliably spot internal defects. The new method developed by the collaborative team of scientists utilizes existing cameras and AI to instantly detect flaws, eliminating the need for expensive X-rays every time. "Our approach can readily be implemented in commercial systems. With only a thermal camera, the machines should be able to detect when and where pores are generated during the printing process and adjust their parameters accordingly," said Kamel Fezzaa, a physicist at Argonne and a member of the scientific team. Eventually, this technology could be paired with automatic corrections, such as adjusting the laser or reprinting a layer, to fix problems as they occur. This makes 3D printing more reliable for mission-critical parts. It could reduce waste, save money, and increase safety. "Our X-ray beams are so intense that we can image more than a million frames per second," added Samuel Clark, another physicist at Argonne. "Next, the researchers will develop sensing technologies that can detect other types of defects that occur during the additive manufacturing process. The goal is to create a system that not only detects defects but can enable repairs during 3D printing," a release by the U.S. Department of Energy stated. The study has been published on the website DOE Pages.

Yahoo
a day ago
- Yahoo
Bottlenose dolphin born at Brookfield Zoo Chicago, takes its first breath on video
A bottlenose dolphin safely delivered a calf early Saturday morning at Brookfield Zoo Chicago, a 'momentous occasion' that marks the first dolphin birth in more than a decade at the west suburban zoo. Allie, a 38-year-old bottlenose dolphin and experienced mother of four, gave birth to the calf — which will be named later this summer — at 12:22 a.m., the zoo said in a news release. Veterinarians estimated that the calf weighs between 33 to 37 pounds and is 115 to 120 centimeters long. 'Every birth is a remarkable learning opportunity, and the scientific information we gain benefits marine conservation efforts,' said Dr. Mike Adkesson, the zoo's president and CEO. 'The birth offers a moment to celebrate the incredible work and dedication of our team to ensure the health and well-being of the animals in our care.' Allie began showing signs of labor Friday morning when her body temperature dropped about a degree, the zoo said. By 11 p.m., the calf's flukes presented itself, and within less than an hour and a half the calf was born, the zoo's first since 2014. A video showed the calf swimming up to the water's surface for its first breath alongside Allie and Tapeko, another dolphin and an experienced mother. 'The calf came out very strong,' Dr. Jennifer Langan, senior veterinarian, said in the video one hour after the delivery. 'It has been breathing well, and it's developing new skills that dolphins have to develop really quickly. That includes learning how to surface to breathe, learning how to move its flukes.' The calf reached other developmental milestones as well, including 'slipstreaming,' which is when a calf gets pulled along by its mother so that it doesn't have to work as hard to swim, the zoo said. The calf's dorsal fin and tail flukes are also pliable and lack firmness, but will gradually stiffen in a few days. These milestones, which staff are monitoring 'around the clock,' are important because although calves are born fully developed after a 12-month gestation, they heavily rely on their mother for nutrition, navigation and to conserve energy. A calf's first year of life can be particularly precarious. In the wild, 1 in 5 calves born to first-time mothers don't survive their first year, the zoo said. 'The first 30 days are a critical time frame for Allie and her calf,' said Dr. Sathya Chinnadurai, the zoo's senior vice president of animal health, welfare and science. 'We're closely monitoring behaviors and milestones to gauge the calf's progress, like its first breath of air, bonding with its mother, growth and an increase in nursing efficiency.' Staff will confirm which dolphin is the calf's father in the coming months, the zoo said. Brookfield Zoo has a long history of dolphin care and research. In 1961, it opened the country's first inland dolphin aquarium. For over five decades, the zoo has also led the Sarasota Dolphin Research Program in Florida, the world's longest-running wild dolphin conservation program, which studies bottlenose dolphins as indicators of the overall health of the marine ecosystem, as well as the presence of diseases and toxins like contaminants, runoff, red tides and algal blooms. The zoo's Seven Seas dolphin habitat is temporarily closed while the calf acclimates to the dolphin group.

Yahoo
a day ago
- Yahoo
Bottlenose dolphin born at Brookfield Zoo Chicago, takes its first breath on video
A bottlenose dolphin safely delivered a calf early Saturday morning at Brookfield Zoo Chicago, a 'momentous occasion' that marks the first dolphin birth in more than a decade at the west suburban zoo. Allie, a 38-year-old bottlenose dolphin and experienced mother of four, gave birth to the calf — which will be named later this summer — at 12:22 a.m., the zoo said in a news release. Veterinarians estimated that the calf weighs between 33 to 37 pounds and is 115 to 120 centimeters long. 'Every birth is a remarkable learning opportunity, and the scientific information we gain benefits marine conservation efforts,' said Dr. Mike Adkesson, the zoo's president and CEO. 'The birth offers a moment to celebrate the incredible work and dedication of our team to ensure the health and well-being of the animals in our care.' Allie began showing signs of labor Friday morning when her body temperature dropped about a degree, the zoo said. By 11 p.m., the calf's flukes presented itself, and within less than an hour and a half the calf was born, the zoo's first since 2014. A video showed the calf swimming up to the water's surface for its first breath alongside Allie and Tapeko, another dolphin and an experienced mother. 'The calf came out very strong,' Dr. Jennifer Langan, senior veterinarian, said in the video one hour after the delivery. 'It has been breathing well, and it's developing new skills that dolphins have to develop really quickly. That includes learning how to surface to breathe, learning how to move its flukes.' The calf reached other developmental milestones as well, including 'slipstreaming,' which is when a calf gets pulled along by its mother so that it doesn't have to work as hard to swim, the zoo said. The calf's dorsal fin and tail flukes are also pliable and lack firmness, but will gradually stiffen in a few days. These milestones, which staff are monitoring 'around the clock,' are important because although calves are born fully developed after a 12-month gestation, they heavily rely on their mother for nutrition, navigation and to conserve energy. A calf's first year of life can be particularly precarious. In the wild, 1 in 5 calves born to first-time mothers don't survive their first year, the zoo said. 'The first 30 days are a critical time frame for Allie and her calf,' said Dr. Sathya Chinnadurai, the zoo's senior vice president of animal health, welfare and science. 'We're closely monitoring behaviors and milestones to gauge the calf's progress, like its first breath of air, bonding with its mother, growth and an increase in nursing efficiency.' Staff will confirm which dolphin is the calf's father in the coming months, the zoo said. Brookfield Zoo has a long history of dolphin care and research. In 1961, it opened the country's first inland dolphin aquarium. For over five decades, the zoo has also led the Sarasota Dolphin Research Program in Florida, the world's longest-running wild dolphin conservation program, which studies bottlenose dolphins as indicators of the overall health of the marine ecosystem, as well as the presence of diseases and toxins like contaminants, runoff, red tides and algal blooms. The zoo's Seven Seas dolphin habitat is temporarily closed while the calf acclimates to the dolphin group.