GET WET!

Ask the veterinarians and biologists collecting dead manatees along Florida’s Atlantic coast this winter, and they’ll tell you starvation is a slow and excruciating way to die.

Organs stop functioning. Cells break down. Muscles waste away. The starving animals are “dissolving on the inside,” said Pat Rose, executive director of the nonprofit Save the Manatee Club.

A series of algae blooms decimated vast seagrass beds where the sea cows once grazed in the Indian River Lagoon on the Central Florida coast. Now they are dying in record numbers, more susceptible to infection and colder, winter waters.

A reported 1,101 manatees died last year, state records show. That’s up to 10% or more of the estimated manatee population in 2016, the most recent number available. More than 700 of those deaths were on the east coast, a few hundred likely due to starvation. This year, at least 350 manatees have died on the east coast since Jan. 1.

The manatee deaths illustrate how ecosystems already weakened by human activities and a changing climate can plunge into disaster when one event spirals through a food chain. And they are the latest and possibly highest profile casualty in a series of similarly devastating events that plague coastal areas around the globe.

Seagrass meadows suffered widespread declines in Chesapeake Bay along the nation’s mid-Atlantic coast. So did seagrass beds in Rhode Island and western Australia. Salt marshes in New England suffered. Kelp forests died off the California coast.

In each case, some combination of the same toxic factors are blamed. Too much wastewater, too much runoff and too much development leave these coastal ecosystems where people live, fish and play weakened and vulnerable. Climate change, in terms of warming temperatures, marine heat waves, flooding rains and higher sea levels add more stress.

By some estimates, up to 30% of the world’s seagrass was lost in the 20th century. Steeper declines began over the past 20 years and then “really accelerated over the last 10 years,” said Mark Bertness, the Robert P. Brown Professor of Biology at Brown University in Providence, Rhode Island.

That’s concerning, he said, because healthy coastal ecosystems provide huge benefits to humans, in terms of things like storm surge protection, carbon storage and fish nurseries

Without more urgent action to clean up waterways and combat global warming, more cascading ecosystem collapses are expected along the world’s coasts.

“People around the world are watching (Florida), fearing they could see similar disasters in their lagoons and estuaries,” said Jessie Jarvis, an associate professor at the University of North Carolina Wilmington who is serving as president of the World Seagrass Association.

Central Florida’s dying seagrass

Seagrass evolved over thousands of years as submerged forests that provide food and shelter to a vast array of marine life. Offshore fish species spawn in coastal seagrass. Sea turtles spend part of their lives there. So do seahorses, sharks, dolphins and many birds, including pelicans and herons.

Seven of the world’s 72 species of seagrass are found in the Indian River Lagoon, a ribbon of waterways along 156 miles of the Florida coast. Once billed as one of the world’s most biologically diverse estuaries, researchers valued its economic contribution at more than $7.6 billion a year, including activities such as fishing, boating and tourism. But the lagoon’s health has been in free fall for more than a decade.

Many point to a severe freeze in 2010 as a turning point. Unusually frigid water temperatures killed massive amounts of fish and drift algae. The algae had helped to filter the water, absorbing nutrients such as nitrogen and phosphorus. When the algae died, it released those nutrients into the water. Hundreds of thousands of dying fish dumped an even bigger slug of nutrients, fueling the growth of other, more harmful algae species.

By 2011, massive harmful algal blooms spread across several parts of the lagoon. At the time, scientists called it a “superbloom” for its unprecedented size. But subsequent blooms, especially in 2020, have been even bigger and more devastating.

Thick, pea soup-like algae blocked the light essential to seagrass survival. Tens of thousands of acres died in 2012 and 2013, and the losses continued with more recent blooms. The grass released even more nutrients as it died. Without strong root systems, bottom sediments stirred up and further clouded the water.

Up to 60% of the grass beds in the lagoon were lost, seagrass scientist Lori Morris with a regional water management agency said during a recent community webinar. And the remaining beds have “hardly any grass.” One estimate puts the overall grass lost as high as 90%.

Starving manatees have been found as far north as Georgia and southward through Miami, said Martine de Wit, veterinarian for the wildlife commission. The deaths have raised critical concerns about this threatened species that was removed from the endangered species list in 2017 and prompted emergency feedings of leafy greens by state and federal officials.

Numerous experts blame partially treated wastewater, failing septic systems, septic tanks where they shouldn’t be, polluted stormwater runoff and its abundance of fertilizers, herbicides and pesticides.

Clean water allows life-giving light

The same challenge faces restoration groups around the country. Improving the water quality is the key to restoring coastal ecosystems everywhere, said Bertness and others.

Seagrass needs more light than any other living plant on the surface of the Earth, said Robert Orth, an emeritus professor at the Virginia Institute of Marine Science. Because their roots are in toxic sediments, it’s hard for the plants to pump oxygen into the leaves.

Too little light proved to be the enemy in New England, where efforts to re-establish and restore one type of seagrass, eelgrass, haven’t worked, Bertness said. New efforts focus on smaller areas where water is clearer, he said, and that’s working better.

Adding filter feeders such as oysters and clams to help clean the water also boosts restoration projects.

In the 64,000-square mile Chesapeake Bay, eelgrass coverage is a fraction of what it was 50 years ago, said Orth, who has been called the “Johnny Appleseed” of seagrass restoration. The bay’s eelgrass has seen a 29% decline in total area since 1991.

Whether or not the eelgrass ever returns is questionable, Orth said. It is temperature and light sensitive, so “unless we figure out a way to get temperatures to drop and make the water clearer, we’re not going to get eelgrass back to anything looking like the past.”

However, seagrass restoration in coastal lagoons along Virginia’s eastern shore has seen better success. Eelgrass declined in the 1930s along its entire north Atlantic range including these seaside lagoons. Eelgrass wasn’t seen in these lagoons until Orth began a restoration program in 2001. Today, after more than 70 million eelgrass seeds were distributed during the past two decades, these lagoons now have 9,500 acres of thriving eelgrass.

“If you get water quality back to where it was, seagrasses will return pretty rapidly,” he said. “If you don’t remove the water quality issues that are influencing it, you’ll never get it back.”

The latest report from the United Nations’ Intergovernmental Panel on Climate Change also concluded water quality improvements can help coastal ecosystems bounce back, be more resilient to the changing climate and provide natural solutions for protecting shorelines from climate change.

Restoration the goal

As the executive director of a coalition of Florida governments known as the Indian River Lagoon Council, Duane DeFreese is all too familiar with water quality concerns.

“We need to get really serious in America about wastewater treatment,” DeFreese said. “We should not be putting these nutrients into surface water and groundwater.”

He remains hopeful water quality can be restored in the lagoon, even though the estimated cost of long-term restoration approaches $5 billion.

Nearly 300 state and federal projects are underway aimed at cleaning up water quality, from muck dredging to removing septic tanks, DeFreese said. The federal infrastructure bill will bring in nearly $1 million a year for the next five years. Even before the manatee deaths started, voters in Brevard County, where the most manatees are dying, had approved a sales tax initiative that will bring in more than $40 million a year for 10 years.

“With every project, we’re making progress,” DeFreese said.

Other work has shown seagrass restoration is expensive and complicated, he said, but not impossible.

“We’re going to get good at seagrass planting within the restoration community, even if that means caging out the marine life to give planted seagrasses a chance to recover,” he said. “Otherwise, it’s almost like putting out a salad buffet. If you put it out now, whether it’s fish, turtles or manatees, whatever you plant will be gone in 10 days.”

Rose remains guardedly optimistic that the water can be cleaned up enough to stop the algae blooms and ensure the manatees’ survival. “We won’t save the manatees in the Indian River Lagoon if we don’t get the water quality right.”

FOR MORE INFORMATION: https://phys.org/news/2022-03-florida-starving-manatees-coastal-ecosystems.html

Recently published research led by University of Hawai’i (UH) at Mānoa scientists highlights the potential for using oceanographic sensors to make accurate predictions of Vibrio vulnificus, an infectious bacterium, in the Ala Wai Canal in Waikiki, Hawai’i. By assessing rainfall, water temperature, dissolved nutrients and organic matter the team now has the ability to forecast potential spikes in levels of the bacteria. 

V. vulnificus, a “flesh-eating” bacterium, lives naturally in the water of the Ala Wai Canal, but infections are rare. V. vulnificus has been relatively understudied in tropical ecosystems and further, the implications of climate change for this and other coastal human pathogens are generally unknown.

The research team collaborated with the UH Strategic Monitoring and Resilience Training in the Ala Wai Watershed (SMART Ala Wai Program) where at least 20 undergraduate students and six graduate students from the UH Mānoa School of Ocean and Earth Science and Technology participated in sample collection from the canal and processing at the Daniel K. Inouye Center for Microbial Oceanography: Research and Education.

Consistent with another recently published UH study, rainfall was found to be critically important for both elevating the pathogen’s abundance in the canal and transporting V. vulnificus to the adjacent Ala Wai Boat Harbor.

“We also found that measuring the amount of a particular kind of dissolved organic matter in the water significantly improved our model’s accuracy in predicting V. vulnificus abundance,” said lead author Jessica Bullington, who was pursuing her Master’s degree in the SOEST Department of Oceanography at the time of this work.

Ocean sensors provide necessary data

Water quality monitoring that involves collecting samples and analyzing them in a laboratory is expensive and often limited to select locations. Fortunately, there are oceanographic sensors that continuously monitor water quality at the mouth of the Ala Wai Canal.

“What is really exciting about our research findings is the ability to use real-time and forecast data from the Pacific Islands Ocean Observing System (PacIOOS)—which includes water temperature, salinity, currents, and dissolved organic matter—to predict V. vulnificus abundance in the canal and harbor now and three days into the future,” said Bullington, who is now a doctoral student at Stanford University. “The next steps are to make these predictions accessible and communicate the risk of infection, both for short-term use and adaptation to the impacts of climate change.”

Warmer waters as climate changes

Because V. vulnificus abundance was higher when temperatures were warmer, and climate change is predicted to increase water temperature in the Ala Wai Canal, the researchers anticipate V. vulnifucus is likely to increase substantially in the canal in the coming decades.

By combining climate change projections of rainfall and air temperature with their computer model of bacteria dynamics, the team found that average V. vulnificus abundance in the canal may increase twice or three times current levels by the end of the century. Armed with this information, communities can make decisions on how to adapt to the changing conditions.

“Ultimately, we wanted to generate something that would be useful for people,” said Bullington. “This project is a great example of one of the many ways in which our departmental expertise can be of service for our local community and coastal management.”

FOR MORE INFORMATION: https://phys.org/news/2022-03-flesh-eating-bacteria-ala-wai-canal.html

Sponges in coral reefs, less flashy than their coral neighbors but important to the overall health of reefs, are among the earliest animals on the planet. New research from UNH peers into coral reef ecosystems with a novel approach to understanding the complex evolution of sponges and the microbes that live in symbiosis with them. With this “genomic time machine,” researchers can predict aspects of reef and ocean ecosystems through hundreds of millions of years of dramatic evolutionary change.

“This study shows how microbiomes have evolved in a group of organisms over 700 million years old,” says Sabrina Pankey, a postdoctoral researcher at UNH and lead author of the study, published recently in the journal Nature Ecology & Evolution. “Sponges are increasing in abundance on reefs in response to climate change and they play an enormous role in water quality and nutrient fixation.”

The significance of the work transcends sponges, though, providing a new approach to understanding the past based on genomics. “If we can reconstruct the evolutionary history of complex microbial communities like this we can say a lot about the Earth’s past,” says study co-author David Plachetzki, associate professor of molecular, cellular and biomedical sciences at UNH. “Research like this could reveal aspects of the chemical composition of the Earth’s oceans going back to before modern coral reefs even existed, or it could provide insights on the tumult that marine ecosystems experienced in the aftermath of the greatest extinction in history that took place about 252 million years ago.”

The researchers characterized almost 100 sponge species from across the Caribbean using a machine-learning method to model the identity and abundance of every member of the sponges’ unique microbiomes, the community of microbes and bacteria that live within them in symbiosis. They found two distinct microbiome compositions that led to different strategies sponges used for feeding (sponges capture nutrients by pumping water through their bodies) and protecting themselves against predators—even among species that grew side by side on a reef.

“The types of symbiotic communities we describe in this paper are very complex, yet we can show they evolved independently multiple times,” says Plachetzki.

And, adds Pankey, “there’s something very specific about what these microbial communities are doing … sponges dozens of times have decided that this diverse arrangement of microbes works for them.”

Leveraging this new genomic approach, the researchers found that the origin of one of these distinct microbiomes, which had a high microbial abundance (HMA) of more than a billion microbes per gram of tissue, occurred at a time when the Earth’s oceans underwent a significant change in biogeochemistry coincident with the origins of modern coral reefs.

While machine learning and genomic sequencing generated the findings Plachetzki calls “a tour de force of microbial barcode sequencing,” this research began far from the lab, in the warm waters of the Caribbean.

“We dove for all 1,400 of these samples,” says Pankey, who went on five expeditions in 2017 and 2018 to collect sponges. “It was a monstrous collection,” she adds, acknowledging that SCUBA diving in the Caribbean has its rewards. The duo credits co-author Michael Lesser, UNH research professor emeritus, for establishing field work techniques, and their co-authors from the University of Mississippi and the Universidad Nacional del Comahue in Argentina for assisting with sponge collection and molecular identification. Former graduate student Keir Macartney also contributed to the study.

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FOR MORE INFORMATION: https://phys.org/news/2022-04-genomic-machine-sponge-microbiome-insights.html

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The Back River in Baltimore County is unsafe for drinking, swimming or any human contact, Maryland environmental officials declared Friday amid ongoing concerns about failing systems at the Back River Wastewater Treatment Plant in Dundalk.

Anyone who touches the water is advised to wash with soap and water as soon as possible, and to seek medical advice if water comes in contact with any open wounds.

The declaration comes after environmental groups have raised concern for months that unsafe bacteria levels are present in the river frequently, and that the public should be notified of the risks when boating or recreating on the river.

The Back River plant, which is owned by the city of Baltimore and processes sewage and wastewater from across the city and much of Baltimore County, has not been properly maintained, state inspectors and environmental groups say. It is failing to properly filter bacteria and pollution before releasing water into the river, they say.

The Maryland Department of the Environment ordered a state takeover of the Back River plant last month as inspections showed water treatment problems were getting worse. But department officials had said that what observers have said recently appeared to be untreated sewage floating in the river were actually floating mats of algae.

Regardless of that question, analysis of water samples taken Tuesday show unsafe levels of fecal bacteria in multiple locations on the river, the department said Friday.

“The health advisory is a necessary and protective step in our broader effort to stabilize the situation and dramatically improve the operation and maintenance of Baltimore’s world-class wastewater asset,” Maryland Environment Secretary Ben Grumbles said in a statement.

Blue Water Baltimore, a water quality monitoring and advocacy group that has been raising concerns about the Back River plant, praised the state for issuing the advisory. The group routinely tests for bacteria and pollutants at 49 sites in waterways around the Baltimore area, and its monitoring first showed signs of problems at both the Back River plant and the Patapsco Wastewater Treatment Plant in Baltimore’s Wagners Point last August.

“This is why water quality monitoring is so important—thanks to the data, we know the Back River is often unsafe for human contact; we are relieved that the state issued an advisory to protect the many people who recreate in the Back River,” said Alice Volpitta, the organization’s Baltimore Harbor Waterkeeper.

The 9-mile Back River drains Northeast Baltimore via Herring Run and part of eastern Baltimore County via Northeast Creek, which means it also handles a lot of storm runoff. Hart Miller Island, a popular recreation spot and boating destination, lies just off its mouth in the Chesapeake Bay.

Signs posted at Cox’s Point Park in Essex, a public park across the river from the wastewater treatment plant, warned visitors Friday to minimize contact with waters, especially when waters are cloudy, saying the pollution is linked to “recent heavy rains, storms or other conditions.” Such signs are often posted around waterways because heavy rain washes surges of wastewater from overflowing sewer systems into streams and rivers.

But in the Back River’s case, that signage may give people the impression that the water is safe if it looks clear or if it hasn’t rained recently, said Angela Haren, senior attorney at Chesapeake Legal Alliance, which is representing Blue Water Baltimore in a lawsuit against Baltimore over the wastewater plant failures.

She said the signs should make clear, in multiple languages, that the health threat is more persistent and severe than that.

“This is 100% of the time right now; not just in heavy rain,” she said.

Haren added that such signs and public notifications also are needed around the Baltimore harbor, where boating and other recreation are common, and so are unsafe bacteria levels

FOR MORE INFORMATION:https://phys.org/news/2022-04-maryland-river-unsafe-human-contact.html

A group of Australian scientists has for the first time unraveled the history of climate change upheaval on the Great Barrier Reef over the past eight millennia.

Led by University of Queensland graduate Dr. Marcos Salas-Saavedra, the team analyzed rare earth elements in drilled reef cores, unveiling a deep history of wild weather.

“Eight thousand years ago, extreme runoff from an intense Indian-Australian summer monsoon affected water quality in the southern offshore Reef,” Dr. Salas-Saavedra said.

“Water in the GBR was much dirtier, and poor water quality is known to be a major cause of reef decline around the world.

“But 1,000 years later, monsoonal rains eased and the water quality greatly improved.

“We noticed water quality declined during times of dampened El Niño Southern Oscillation frequency, which may have led to more La Niña-dominated wet climates in Queensland at those times—like the weather we have seen this year in Queensland.”

“But as El Niño-dominated weather patterns became established, southern Great Barrier Reef water quality again improved to give us the beautiful Reef we know and love.”

The new data allows researchers to understand for the first time what water quality was like on the Great Barrier Reef over an extended period.

Professor Gregory Webb said the study provides a new and independent source of paleoclimate data, not only for the Great Barrier Reef, but potentially for reefs around the globe.

“Knowing more about how the Great Barrier Reef responded to past environmental changes is essential to help inform us how reefs can be better managed in the future,” Professor Webb said.

“We have created a toolkit to understand subtle differences in water quality—even in offshore reefs—and it can be applied over much longer time frames where reef core material is available.

“Importantly, this type of analysis enables us to examine how ancient water quality may have impacted coral growth rates, overall reef growth rates, and any shifts in reef ecology at the same time.”

Reef cores were recovered from Heron and One Tree reefs by UQ’s Dorothy Hill Research Vessel, before Professor Jianxin Zhao dated and analyzed the cores at UQ’s Radiogenic Isotope Facility.

The analysis focused on rare earth elements preserved in microbialites—rocks made by microbes—that have been growing throughout the Great Barrier Reef’s history.

The research is published in Chemical Geology.

FOR MORE INFORMATION: https://phys.org/news/2022-05-years-great-barrier-reef-climate.html

2020 marked Lake Michigan’s highest water level in 120 years, experts said, and climate variance makes future water levels challenging to predict. Coastal impacts are well-documented, but the effect of lake level rise on the area’s inland waterways is poorly understood. A University of Illinois Urbana-Champaign study examined how Lake Michigan’s rising levels affect water quality, flood control and invasive species management within the Chicago-area waterway system that connects the lake to Illinois, Indiana and the Mississippi River basin.

The study, led by civil and environmental engineering professor Marcelo Garcia and graduate student Dongchen Wang, focused on how lake-level rise influences the unique bidirectional flow of the Chicago-area waterway system—initiated by the engineered reversal of the Chicago River in 1900—and its connection to the Calumet-area waterway subsystem situated along the Illinois-Indiana border.

The study is published in the Journal of Great Lakes Research.

“The Calumet-area waterway subsystem was examined in detail for this study because it serves as the Chicago-area’s only primary connection to Lake Michigan not completely controlled by hydraulic structures,” Garcia said.

The researchers built complex computer models—calibrated and validated against observed field data—to reproduce the effect of past lake-level rise on the Calumet waterway subsystem’s flow. To study the impact of future rises, the researchers plugged realistic increases in the Lake Michigan levels into their model.

“Our models successfully replicated the observed bidirectional flow and water levels of the Calumet subsystem,” Wang said. “With that, we could look at various hydraulic scenarios. For example, when lake levels are 0.5 feet below the Calumet subsystem’s normal level, the discharge in the Grand Calumet River is around zero, and water flows east toward Indiana and the Great Lakes basin. However, when we increase the lake level to 1.5 feet above normal, the flow reverses direction and drains west into Illinois toward the Mississippi basin.”

The area surrounding the Calumet subsystem has a long history of heavy industry, and streams and rivers in the area contain chemical pollutants, the researchers said. Restoration and environmental cleanup projects have left the system’s channels broader and deeper after the dredging of polluted sediments. If the lake remains at a high level, the system could serve as an uncontrolled connection for invasive species to migrate between Lake Michigan and the Illinois and Mississippi rivers. 

“State and federal agencies have made efforts to separate the Great Lakes basin and Mississippi River basin to control the spread of pollution and invasive species,” Wang said. “However, we can now confirm that water can flow freely via the Grand Calumet River to Lake Michigan—or backward through the Chicago area waterway system toward the Mississippi River basin when the lake is at a high level—affecting an area much greater than originally understood,” Wang said.

The study found that the spread of pollutants and invasive species through bidirectional water flow is not the only issue associated with Lake Michigan’s era of high water levels.

“This work helps us better understand how the entire Chicago area waterway system will respond to flooding,” Garcia said. “It will also better define the need for policy change related to Illinois’ Lake Michigan water diversion laws. The researchers said there is still an immense amount of work needed to better characterize these initial findings and hope that the study results will motivate state and federal agencies to increase support for continued research.

FOR MORE INFORMATION: https://phys.org/news/2022-06-lake-michigan-affects-inland-waterways.html

In Indigenous communities that have lacked access to safe water for years, getting access to a safe water supply is crucial. However, perceptions of the water supply—not just how it tastes and smells, but also trust in the source’s safety—affect consumption.

It is estimated that Canada is in eighth position of the most renewable freshwater resources per capita on the planet. Unfortunately, not everyone has access to safe drinking water. In particular, water security is a challenge for Indigenous communities. Twenty-eight First Nations still have long-term drinking water advisories, meaning no home access to safe drinking water. 

This lack of safe water may be linked to indirect adverse health effects. These include things like drinking sweetened beverages as an alternative to water, and not being able to achieve optimal hygiene or prevention of infection transmission (for example, hand washing to prevent COVID-19). It is also associated with the environmental burden of things—like single-use plastic bottles—as well as economic, social, cultural and spiritual impacts.

Limited access to safe drinking water

In December 2021, a compensation process was authorized for those who suffered from a lack of reliable access to clean water, resulting in an $8-billion settlement. The federal government has promised to end all long-term drinking water advisories on First Nations communities by 2025, after failing to achieve this by the previous deadline of March 2021.

The perception of tap water

After decades of not having access to safe water, Potlotek First Nation (Nova Scotia) now has a proper water treatment plant. However, because of their experiences with unsafe water, residents still have concerns and are skeptical about the safety of the water. Similar concerns about drinking water quality have been reported as far away as remote Indigenous communities of Australia. 

Taste and smell are the main factors impacting the perception of water and consumption practices. We may think that remote northern Indigenous communities have more trust in their tap water, as they have access to pure water far from urban centers. Two of the top 10 biggest lakes on the planet are found in northern Canada, in the Northwest Territories, home of only about 45,000 residents. 

However, resource development and climate change, colonial relations and historical polluting industrial activities may have contributed to the perception of low-quality water in remote communities, resulting in low trust in the drinking water supply.

FOR MORE INFORMATION: https://phys.org/news/2022-06-northern-indigenous-perceptions.html

A new Florida Tech study investigates symbiotic relationships between bacteria and algae that can trigger the occurrence, or worsening, of harmful algal blooms.

The research paper, “The in-situ release of algal bloom populations and the role of prokaryotic communities in their establishment and growth,” was from ocean engineering and marine sciences professor Kevin Johnson, Florida Tech alumnus Xiao Ma of the South China Sea Institute of Oceanology and Southern Marine Science and Engineering Guangdong Laboratory, as well as researchers from the University of Chinese Academy of Sciences. The paper will be published in the July edition of the journal Water Research.

The research offered further insight into how blooms get started. Understanding this allows researchers to then explore how they evolve into harmful algal blooms (HABs), which affect marine life and water quality in lakes and estuaries worldwide. The team studied what facilitated bloom initiation, looking at blooms in their earliest stages before they can cause harm.

According to Johnson, HABs in the Indian River Lagoon have killed an estimated 60,000 to 70,000 acres of seagrass by blocking life-sustaining sunlight. Seagrasses are critical habitatfor fish and small animals, and a food source for many ocean grazers such as manatees. Seagrass loss foreshadows the collapse of an economically and ecologically important coastal ecosystem.

“Most local harmful blooms are the algae blooming out of control, blocking light and depleting oxygen” Johnson said. “They’re so out of control, they take over the water column. The other things that usually live there are suppressed and choked, and the water becomes opaque, either greenish or brownish.”

On top of the physical and environmental factors controlling the algal bloom, the team now has evidence that bacteria living in the water column help algae by producing vitamins and nutrients they need. In turn, the algae convert those nutrients to forms useful to bacteria. It’s a tight circle of symbiosis.

Nitrogen availability plays a strong factor in the health of lagoon. Without human-sourced nitrogen, such as fertilizer or other pollutants, algae are not able to bloom, the water column stays clear, and seagrasses have sufficient sunlight to grow. Johnson said there’s plenty of nitrogen around in the absence of pollution, but the common form is not useful to most life in the lagoon.

“Nitrogen is everywhere but it’s in the wrong form,” he said. “Without the bacteria converting that nitrogen, the algae are very limited in how much they can bloom. In an unpolluted estuary, bacterial nitrogen fixation makes occasional algal blooms possible. However, in a eutrophic estuary, where human-sourced excess nutrients are abundant, algae bloomsare more frequent and severe, reaching harmful levels. Those excess nutrients are going to include a lot of nitrogen that’s already organic nitrogen, meaning it’s already been fixed or converted to a form that the algae can use. Estuaries around the world are having similar problems.”

The team hopes the work done in this paper will provide a better understanding of the complex relationships between bacteria and algae, and the nutrients they share with one another. This could provide insight into recent algal blooms and resulting fish kills plaguing the Indian River Lagoon.

“I think it’s almost certain that the bacterial community and harmful algal blooms in the Indian River Lagoon are connected, and we don’t know what that relationship is,” Johnson said. “I’d like to understand that symbiosis and how bacteria might control harmful algal blooms in the IRL. Without understanding what bacteria are doing, we’ve only got part of the story.”

FOR MORE INFORMATION:https://phys.org/news/2022-06-symbiotic-relationships-trigger-algal-blooms.html

High concentrations of disinfection byproducts in tap water are a possible culprit in adverse health outcomes.

A recent study by Prof. Yu Wenzheng’s team from the Research Center for Eco-Environmental Science of the Chinese Academy of Sciences highlighted this risk and suggested sustainable solutions such as ozone biofiltration and nanofiltration to increase the safety of drinking water. This study was published in Nature Sustainabilityon June 9. 

The provision of safe, reliable drinking water is fundamentally important. Although disinfection is meant to make water safer to drink, byproducts of chlorine-based disinfection are harmful substances that pose a long-term public health risk. 

In this study, the researchers conducted a national assessment of tap water across China. They found notable geographical differences in disinfection byproduct concentrations in tap water across China, with higher concentrations in the northeast and the mid-Yangtze River region. 

Based on officially published disease data, the researchers then verified the spatial relationship between disinfection byproducts and adverse health outcomes. That is, regions with a high incidence of adverse health outcomes are characterized by significantly higher concentrations of disinfection byproducts than other areas. 

However, the toxicity of disinfection byproducts is not only determined by their concentration, but also by their composition. Bromine-containing disinfection byproducts are more toxic than those containing chlorine. Coastal regions with seawater intrusion showed higher bromine-containing disinfection byproducts and associated toxicity. 

In addition, the concentration of bromine-containing disinfection byproducts is strongly associated with GDP, pollutant discharge, and other human factors. “Therefore, countries and regions experiencing rapid socioeconomic development might be facing higher disinfection byproduct toxicity, and they should consider adopting solutions to address the potential health risk caused by poor drinking water,” said Yu Wenzheng, corresponding author of the study. 

Advanced water treatment such as ozone biofiltration can effectively remove disinfection byproduct precursors, according to the researchers. In Shanghai, more than 60% of the city’s water plants use such biofiltration to enhance their water treatment, resulting in a much lower disinfection byproduct level than China’s three other largest cities. Therefore, this approach can be used to reduce the risk of disinfection byproducts in economically developed areas. 

Sourcing water from less polluted areas may also be a solution, according to the researchers. For example, water supplied to the Haihe River region through the South-to-North Water Diversion Project has not only alleviated the region’s water scarcity, but has also improved water quality in an area that previously suffered from severe organic water pollution. 

In addition to proposing altering water sources and enhancing water treatment processes, the researchers also demonstrated that nanofiltration is as an effective household treatment to improve water quality and reduce the health risk of disinfection byproducts. 

“Nanofiltration is a promising point-of-use technology to guarantee household drinking water safety. Besides disinfection byproducts, other potential microcontaminants in tap water can also be removed by nanofiltration,” said Yu. 

All in all, rapid urbanization is raising concerns about the impact of various pollutants on drinking water and health. “This is the first attempt to evaluate the health risk of tap water,” said Liu Mengjie, first author of the study. “We are hoping to see more intensive and detailed surveys of disinfection byproducts and other contaminants performed at the national level.”

According to the researchers, high-resolution spatial and temporal data will enable researchers to better reveal the relationship between tap water quality and human health, thus helping to lower tap water risks.

FOR MORE INFORMATION: https://phys.org/news/2022-06-scientists-solutions-china-risky.html

The Chesapeake Bay once produced tens of millions of bushels of oysters a year. Today, the oyster harvest is below one percent of these historic highs. What happened?

“With modern farming and urban development in the watershed around the Bay during the mid-20th century, water quality declined rapidly,” says Ray Weil, a professor of soil science at the University of Maryland. “Soon the oysters disappeared, many of the fish nearly went extinct, and the crabs were threatened.”

Weil studies ways to help the Chesapeake Bay recover. His research focuses on one of the key culprits in the bay’s decline: nutrients. Key plant nutrients like nitrogen and phosphorous are good for crops, Weil says. “However, in waterways, nitrogen also stimulates the production of plants. In this case it’s aquatic weeds and algae,” he says. All that extra biomass dies and rots, removing oxygen from the water. Lack of oxygen in the waters is a major threat to life in the Chesapeake Bay. In addition, some algae can be toxic to people and fish.

Weil’s study was published in Journal of Environmental Quality, a publication of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

While the Chesapeake Bay has lost some of its luster due to nutrient challenges, it still provides many benefits to nearby residents. It is the second largest estuary—a habitat of brackish water—in the world. The bay itself is roughly 200 miles long. But its watershed covers 64,000 square miles across six states and Washington, D.C. About 500 million pounds of seafood are harvested from the bay each year. The habitat also cleans water while providing breeding grounds for important wildlife.

To help their struggling waterway, Maryland residents voted to tax themselves to provide incentives to farmers to grow cover crops. These are crops that farmers do not sell, but can hold onto excess nitrogen, keeping it out of waterways.

In Weil’s latest research, he studied how the timing of cover crop growth affected their ability to keep nitrogen out of the Chesapeake Bay water. Cover crops are typically planted late in the year after farmers have harvested their cash crops. However, his lab’s previous research indicated that this was probably too late for cover crops to be effective in capturing nitrogen. The key metric is how much nitrogen drains through the soil to groundwater; a process known as leaching.”Essentially we thought that the critical nitrogen capture action takes place before winter dormancy rather than during the winter and spring when the actual leaching is occurring,” says Weil. To test the idea, his lab planted three different types of cover crops at four different times in the fall across two years. The crops included winter rye, radish, and a mix of rye, radish, and clover. The planting dates ranged from mid-August to mid-October.

FOR MORE INFORMATION: https://phys.org/news/2022-07-crops-chesapeake-bay.html