It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Thursday, November 03, 2022
COVID-19 case investigation, contact tracing in New York City
About The Study: Researchers describe the establishment, scaling, and maintenance of Trace, New York City’s COVID-19 contact tracing program and provide data on outcomes during its first 17 months.
Authors: Kathleen Blaney, M.P.H., R.N., of the New York City Department of Health and Mental Hygiene in Queens, New York, is the corresponding author.
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
About The Study: In this analysis of the top 1,000 generics in Colorado’s all-payer claims database in 2019, researchers identified 45 high-cost products that had lower-cost therapeutic alternatives of same clinical value. Overall, high-cost generics were 15.6 times more expensive than their therapeutic alternatives (median values). If the lower-cost alternatives had been used, total spending would have been reduced by 88%. Substitution of high-cost generics may provide a simple pathway to offer the same therapeutic benefit at lower cost to patients and insurers.
Authors: Mariana P. Socal, M.D., Ph.D., of the Johns Hopkins Bloomberg School of Public Health in Baltimore, is the corresponding author.
Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.
VIDEO: WATCH A ZEBRAFISH SWIM ALONG WITH SHIFTING PATTERNS, PROJECTED ONTO THE BOTTOM OF ITS TANK. THIS EXPERIMENT PROVIDED EVIDENCE THAT FISH TAKE VISUAL MOTION CUES FROM BELOW.view more
CREDIT: TOD THIELE/UNIVERSITY OF TORONTO
Just as you might look down at the sidewalk as you walk, fish look downward when they swim, a new study by a Northwestern University-led international collaboration has confirmed.
The study is the first to combine simulations of zebrafish’s brain, native environment and spatially-varying swimming behavior into one computational model. By analyzing this model, the researchers concluded that this quirk — looking down while swimming forward — is an adaptive behavior that evolved to help the fish self-stabilize, as when swimming against a current.
As water moves, fish are constantly trying to self-stabilize in order to stay in place — rather than getting swept away in a moving stream. Focusing on other fish, plants or debris might give the fish a false sensation that it’s moving. The stable riverbed below them, however, gives fish more reliable information about their swimming direction and speed.
“It’s similar to sitting on a train car that isn’t moving. If the train next to yours starts to pull to away from the station, it can trick you into thinking you are moving too,” said Northwestern’s Emma Alexander, who led the study. “The visual cue from the other train is so strong that it overrides the fact that all of your other senses are telling you that you are sitting still. That’s exactly the same phenomenon that we are studying in fish. There are many misleading motion cues above them, but the most abundant and reliable signals are from the bottom of the river.”
The study will be published Nov. 2 in the journal Current Biology.
Alexander is an assistant professor of computer science in Northwestern’s McCormick School of Engineering, where she runs the Bio Inspired Vision Lab.
The researchers collected video data a forested stream with a sandy substrate and low-to-medium flow.
CREDIT
E. Alexander/Northwestern University
Going ‘back to the source’
To conduct the research, Alexander and her collaborators focused on zebrafish, a well-studied model organism. But, although many laboratories have tanks full of zebrafish, the team wanted to focus on the fish’s native environment in India.
“It was recently discovered that fish respond to motion below them more strongly than motion above them. We wanted to dig into that mystery and understand why,” Alexander explained. “Many zebrafish that we study grow up in lab tanks, but their native habitats shaped the evolution of their brains and behaviors, so we needed to go back to the source to investigate the context for where the organism developed.”
Armed with camera equipment, the team visited seven sites across India to gather video data of shallow rivers, where zebrafish naturally live. The field team encased a 360-degree camera inside a waterproof diving case and attached it to a remotely-controlled robotic arm. Then, they used the robotic arm to plunge the camera into the water and move it around.
“It allowed us to put our eyes where the fish eyes would be, so it’s seeing what the fish see,” Alexander said. “From the video data, we were able to model hypothetical scenarios where a simulated fish moved arbitrarily through a realistic environment.”
‘Wait for me!’
Back in the lab, the team also tracked zebrafish’s motions inside a ball of LEDs. Because fish have a large field of view, they do not have to move their eyes to look around like people do. So, the researchers played motion stimuli across the lights and watched the fishes’ responses. When patterns appeared on the bottom of the tank, the fish swam along with the moving patterns — more evidence that the fish were taking their visual cues from looking downward.
“If you play a video with moving stripes, the fish will move along with the stripes,” Alexander said. “It’s like they are saying ‘wait for me!’ In the behavioral experiment, we counted their tail beats. The more they wagged their tails, the more they wanted to keep up with the moving stripes.”
The team then abstracted data from its videos and combined it with data from how motion signals get encoded into the fish’s brain. They fed the datasets into two pre-existing algorithms used for studying optic flow (or the movement of the world across our eyes or camera lenses).
Ultimately, they discovered that in both scenarios — in the wild and in the lab — zebrafish look down when swimming forward. The researchers concluded that fish look down to understand their environment’s motion and then swim to counteract it — to avoid being swept away.
“We tied everything together into a simulation that showed that, in fact, this is an adaptive behavior,” said Alexander, who led the computational part of the study. “The water surface is constantly moving, and other fish and plants are moving by. Fish are better off omitting that information and focusing on the information below them. Riverbeds have a lot of texture, so fish are seeing strong features they can track.”
Building better robots
Not only does this information gives some insight into fishes’ behavior, it could also inform designs for artificial vision systems and sophisticated bio-inspired robots.
“If you were making a fish-inspired robot and you just looked at its anatomy, you might think ‘the eyes are pointing sideways, so I’m going to point my cameras sideways,’” Alexander said. “But it turns out that the eyes are pointing sideways because they are balancing several tasks. We think they point sideways because it’s a compromise — they look upward to hunt and downward to swim.”
The study, “Optic flow in the natural habitats of zebrafish supports spatial biases in visual self-motion estimation,” was supported by the Human Frontier Science Program Young Investigator grant (HSFP RGY0079), the National Institutes of Health (grant number NIH EY003176) and the Werner Reichardt Centre for Integrative Neuroscience (grant number EXC307).
The practice of moving our clocks forward, resulting in a later sunset, reduces night-time associated car accidents with deer by 16 percent. Researchers developed a model, publishing November 2 in the journal Current Biology, that demonstrates the benefits that permanent daylight savings time has, not only in saving animal lives but also in reduction of collision costs and human injuries.
“We saw these huge, abrupt shifts in human activity associated with the timing of sunrise and sunset, so it got us thinking if humans are responding to clock time, whereas animals are responding to the daylight time, does that then create more opportunities for human wildlife conflict?” says first author Calum Cunningham (@CalXCunningham), a biologist from the University of Washington School of Environmental and Forest Sciences.
Using data from 23 state agencies from the US Department of Transportation, Cunningham’s team analyzed 1,012,465 deer-vehicle collisions and 96 million hourly traffic observations across the United States. Their analysis showed that collisions are 14 times more frequent 2 hours after sunset than before. Even more striking, the rate of deer-vehicle collisions increased by 16 percent the week following the change to standard time.
Taking these numbers, the researchers were able to predict that if daylight savings time became year-round it would prevent 36,550 deer deaths, 33 human deaths, 2,054 human injuries, and $1.19 billion in collision costs annually. The data on car collisions is most likely vastly underreported, and these numbers are likely to be much larger than stated.
“It surprised me how striking this pattern was, of how much more likely deer are to get struck in the hour or two after darkness," says Cunningham. “This one-hour shift in human activity could have such a significant effect.”
Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.
In much of the United States, there is a twice-yearly shift in timekeeping between standard time and daylight saving time, or DST, which delays both sunrise and sunset to make mornings darker and evenings brighter. Recently, scientists, policy experts, lawmakers and citizens have debated abandoning the twice-a-year switch and adopting either year-round standard time or DST.
A team of researchers at the University of Washington — led by postdoctoral researcher Calum Cunningham and Laura Prugh, an associate professor of quantitative wildlife sciences — have found that one of those options would sharply reduce a hazard common to much of the country: deer-vehicle collisions. In a paper published Nov. 2 in Current Biology, they report that adopting permanent DST in the United States would reduce deer-vehicle collisions and likely prevent an estimated 36,550 deer deaths, 33 human deaths, 2,054 human injuries and $1.19 billion in costs each year. Deer-vehicle collisions would decrease under permanent DST because skies would be brighter later into the evening.
There are an estimated 2.1 million deer-vehicle collisions in the United States each year, killing about 440 people, causing 59,000 injuries and costing upwards of $10 billion.
“Wildlife-vehicle collisions are a huge and growing problem,” said Cunningham. “There are social costs — people killed and injured — and it’s also a conservation problem as it’s one of the largest sources of human-caused mortality of wildlife.”
Cunningham, Prugh and their colleagues analyzed wildlife-vehicle collision data from 23 states. The vast majority of these were collisions involving two widespread species of deer, white-tailed deer that predominate in the eastern U.S. and mule deer, which are more common in the western U.S.
The dataset, which includes more than 1 million deer-vehicle collisions from 1994 to 2021, revealed that the risk of deer-vehicle collision depends on the overlap of both human and deer activity. Deer and related species are crepuscular, meaning they are most active around dawn and dusk. The team found that most collisions occurred in the hours between sunset and sunrise the next morning. Collisions were 14 times more frequent two hours after sunset than two hours before sunset.
The researchers found that deer-vehicle collisions peak in the fall, with nearly 10% occurring during the two-week period around the switch from DST to standard time. The shift itself causes an abrupt increase in the amount of driving after sunset, which corresponded with a 16% increase in deer-vehicle collisions in the week following the time shift.
For ungulates like deer, fall is also the “rut,” their mating season, during which their activity level increases by as much as 50%.
“We believe that this fall spike really happens due to the overlap of these two factors: the breeding season and the change from daylight saving time back to standard time,” said Prugh. “We don’t see a corresponding shift in deer-vehicle collisions in the spring during the other time change, and we believe that’s in part because spring is not a breeding season for deer.”
The patterns that Cunningham, Prugh and their colleagues found on deer-vehicle collisions allowed them to model collisions under permanent standard time and permanent DST. They estimate an increase of 73,660 deer-vehicle collisions under permanent standard time, with 66 additional human deaths and 4,140 additional injuries, and an added $2.39 billion in collision costs. Permanent DST showed the opposite trend, with a decrease of about 2.3% in deer-vehicle collisions over a full year. Both scenarios would do away with increased accidents caused specifically by the biannual time-shift and the subsequent “social jetlag” caused by out-of-sync circadian rhythms.
Vehicle collisions are a major source of human-wildlife conflict. Since human societies in modern times tend to live their lives more by clocks than the sun’s position in the sky, understanding the factors that lead to these collisions could help save lives and prevent injury, Cunningham said.
“Humans today have this ‘evening bias’ in our activity: we get up later and stay active later than what the sun is telling us to do,” said Cunningham. “As long as people are living their lives ‘by the clock,’ which animals do not, people need to be aware of risks and make adjustments where we can. If people are thinking about what they can do for wildlife and for their own lives, reducing driving during dark hours is likely to help significantly. In areas with deer, the risk of harming wildlife and yourself while driving is 14 times higher when it is dark.”
Co-authors on the paper are Tristan Nuñez, Yasmine Hentati, Ben Sullender, Catherine Breen, Taylor Ganz, Samantha Kreling, Kayla Shively, Ellie Reese and Jeff Miles, all in the UW School of Environmental and Forest Sciences. Cunningham was funded by the Australian Fulbright Commission.
CREDIT: JOSEP CARRERAS LEUKAEMIA RESEARCH INSTITUTE
Researchers from the Epigenetics and Immune Disease Lab at the Josep Carreras Leukaemia Research Institute has recently shown that vitamin C improves the immunogenic properties of dendritic cells, in vitro. Results recently made public show that treating the cells with vitamin C leads to a more consistent activation of genes involved in the immune response, mainly through DNA demethylation, a kind of epigenetic reprogramming. This discovery may be useful to generate more potent dendritic cell-based therapies in the future.
Since the onset of anticancer cell therapies, those that use living cells to find and eliminate tumors, many types of immune cells have been used. The best-known cell therapies use lymphocytes, as in the highly successful CAR-T therapies. Recently, dendritic cells have attracted the scientists’ attention thanks to its ability to uptake and present antigens (small parts of a pathogen or a cancer cell) to the T-lymphocytes and induce an antigen-specific potent immune activation. On this regard, loading dendritic cells with specific antigens to create immune memory constitute the so-called DC-vaccines.
To study dendritic cells in the lab, researchers differentiate them from monocytes (also an immune cell) using a particular set of molecular signaling. This differentiation is accomplished through a complex set of gene activation processes in the nucleus, mostly thanks to the activity of the chromatin remodeling machinery spearheaded by the TET family of demethylases, proteins that act upon the DNA epigenetic marks.
Vitamin C was known to interact with several TET proteins to enhance its activity, but the specific mechanism was still poorly understood in human cells. In a recent publication at the prestigious journal Nucleic Acids Research, a team lead by Dr. Esteban Ballestar hypothesized that treating monocytes in vitro while differentiating into dendritic cells, would help the resulting cells be more mature and active.
Actually, the researchers proved that vitamin C-stimulated dendritic cells loaded with antigens specific for the SARS-CoV-2 virus were able to activate T cells in vitro more efficiently than non-treated cells, showing the superiority of DC-vaccines treated with vitamin C.
Overall, these new findings support the hypothesis that treating monocyte-derived dendritic cells with vitamin C may help generate DC-vaccines with higher performance. After consolidating these results in preclinical models and, hopefully, in clinical trials, a new generation of cell therapies based on dendritic cells may be used in the clinic to fight cancer more efficiently.
IMAGE: SILAS LACAGNIN GAZES AT HIS MOTHER, ANSLEY LACAGNIN, WHILE SHE SINGS TO HIM.view more
CREDIT: VANDERBILT UNIVERSITY MEDICAL CENTER
Engaging infants with a song provides a readymade means for supporting social development and interaction, according to a study published by the Proceedings of the National Academy of Sciences.
Researchers at Vanderbilt University Medical Center (VUMC), Marcus Autism Center, Children’s Healthcare of Atlanta, and Emory University School of Medicine enrolled 112 infants who were either 2 months or 6 months old.
The study tracked infants’ moment-by-moment eye-looking to reveal that the rhythm of caregivers’ singing causes infant eye-looking to become synchronized or entrained to the caregivers’ social cues at sub-second timescales.
As early as 2 months of age, when infants are first engaging with others in an interactive manner, infants were two times more likely to look to the singers’ eyes time-locked to the musical beat than would be expected by chance.
By 6 months of age, when infants are highly experienced in face-to-face musical games and are developing increasingly sophisticated rhythmic and communicative behaviors like babbling, they were more than four times as likely to look to the singers’ eyes synchronized to the musical beats.
“Singing to infants seems like such a simple act, but it is full of rich and meaningful social information,” said study lead author Miriam Lense, PhD, assistant professor
of Otolaryngology and co-director of the Music Cognition Lab at VUMC. “Here we show that when caregivers sing to their infants, they are intuitively structuring their behavior to support the caregiver-infant social bond and infant social learning.”
During testing, researchers used eye-tracking technology to measure every movement of each infant’s eyes while they watched videos of people engaging them with song.
“For this study, we used videos of singing rather than live singing to ensure that any change in infant looking behavior was due to the infant, and not the singer adjusting to the infant,” Lense said. “Infants could look anywhere while watching the videos but we found that their looking behavior was not random.”
“Critically, the predictable rhythm of singing is essential for this entrained social interaction. When we experimentally manipulate the singing so that it no longer has a predictable rhythm, entrainment is disrupted and infants no longer successfully synchronize their eye-looking to the caregivers’ social cues,” she added.
Researchers confirmed their findings in a different group of 6-month-old infants who watched both the original videos of singing, as well as videos that had been manipulated to be jittered so that their rhythms were no longer predictable.
While the infants again displayed entrained eye-looking to the original videos when the singing was rhythmically predictable, this time-locked eye-looking effect was no longer present when the predictable rhythm had been disrupted.
“This is important because it reveals a remarkable physical coupling between caregiver behavior and infant experience,” said Warren Jones, PhD, the study’s senior author and Nien Distinguished Chair in Autism at Emory University School of Medicine. “Without conscious awareness, something as simple and intuitive as caregiver singing sets in motion a whole cascade of behaviors that alters infants’ experiences.”
“Although what a caregiver expresses is important, when and how they express social cues is particularly critical for infant-caregiver communication,” Lense added. “Rhythmic predictability – a universal feature of song – is an integral mechanism for structuring social interactions and supporting infant social development.”
Reyna Gordon, PhD, associate professor of Otolaryngology and co-director of the Music Cognition Lab at VUMC, said the study underscores that making music is not only about entertainment: making music is a core aspect of early socio-emotional development.
“It is remarkable that these infants are basically tracking the beat of music with their eyes by modulating their eye contact with the singer’s eyes around the beat (or pulse) of singing,” said Gordon, who was not involved in the study.
“These findings represent a major step forward in our understanding of the extent that very young children are sensitive to musical rhythm, suggesting that innateness for music is intertwined with early social engagement,” she added.
The study was funded by the National Institutes of Health (National Institute of Mental Health, National Center for Complementary and Integrative Health, National Institute for Deafness and Communication Disorders) and the GRAMMY Foundation.
Lense said her team has now extended the research to study synchronization in autism as part of the Sound Health Initiative, a partnership between the National Institutes of Health (NIH) and the John F. Kennedy Center for the Performing Arts, in association with the National Endowment for the Arts.
JOURNAL
Proceedings of the National Academy of Sciences
ARTICLE TITLE
Music of Infant-Directed Singing Entrains Infants' Social Visual Behavior
Access to media amplifies negative effects of terrorism on school enrolment in Kenya
Media coverage of terrorist attacks significantly raises fear amongst families and leads to children being kept out of schools in Kenya, new research reveals.
Media coverage of terrorist attacks significantly raises fear amongst families and leads to children being kept out of schools in Kenya, new research reveals.
Kenyan families with access to radio, mobile phones or TV are found to be significantly more afraid of terrorism and are less likely to send their children to school.
The new study by Lancaster University Management School and Bocconi University in Italy, published in the Journal of the European Economic Association, finds that Kenyan parents with access to mass media believe that the risk of dying in a terrorist attack is 12 times larger than actual rates. As a result, these parents are more likely to keep their children out of school.
Comparing school enrolment rates over time, the study finds that the negative effect of terrorist attacks on school enrolment is twice as large for children with access to mass media, than for children without.
“Terrorism differs from other types of violence such as war or gun crime, in that it results in relatively low casualty numbers and causes minimal damage to infrastructure,” co-author Dr Marco Alfano from Lancaster University Management School explains. “Nevertheless, terrorism can severely affect economies by heightening fears.
“Our data shows that while al-Shabaab rarely targets educational institutions, their attacks decrease school enrolments substantially in Kenya. Crucially, results show that this negative effect doubles in size if parents have access to mass media, such as the radio, for instance. This suggests that media coverage plays a crucial role in stoking fears and keeping children out of school.”
Researchers say that families without media access react predominantly to attacks close to their homes, whereas families with access to media keep their children out of school in response to terrorist attacks happening more than 100km away.
“This loss of education is significant,” co-author Dr Joseph-Simon Görlach from Bocconi University adds. “The decline in school enrolment leads to decreased earnings later on in life when compared to peers in areas with no terrorist attacks. We find media coverage of terrorist events reduces children’s earnings in later life by around 25% of a year’s income.”
The study saw researchers use geo-coded data on wireless signal strength for radio and television and the staggered rollout of mobile phone coverage to study the effect of exposure to mass media from both a geographical and chronological point of view.
They analysed the geographical concentration of terrorist attacks using precise information from the Global Terrorism Database and, by studying the chronology of attacks over a long period of time, the authors were able to identify variation and trends in the data. They then used three independent data sources on school attendance and enrolment in Kenya (the Hunger Safety Net Program and the 2009 and 2014 rounds of country-wide Demographic Health Survey, and county level administrative data) along with Afrobarometer for data capturing public attitudes as part of the study. In assessing trends from these multiple sources, then overlaying the geographical coordinates of respondents’ homes in relation to radio signal coverage and mobile network data, the authors were able to show that each terrorist attack decreases school enrolment by around 0.4-0.5 percentage points for households without media access. For households with wireless signal coverage for radio, telephone or television, the effect is a statistically significant 0.5-0.7 percentage points stronger.
“This study should be useful for Kenyan Government and other similar nations that are pouring incredible resource and finances into incentives to boost school attendance and the quality of education for young people,” Dr Alfano continues. “Our results show that access to media has significantly increased fear of terrorism in the country and this has a significant ripple-effect which is impacting younger generations who are being kept out of school and suffer financially later in life.
“Our results could serve as a caution against sensationalism and in favour of moderate and fact-oriented reporting of terrorist events. Providing children with fast, reliable and secure transport to school may also mitigate some of these negative effects. These changes would likely make a considerable difference to children’s education and Kenya’s long-term growth and development.”
CORVALLIS, Ore. – A chemical analysis of sediment cores from the North Pacific Ocean show a consistent pairing of volcanic ash and hypoxia, a low ocean oxygen interval spanning thousands of years, during times of rapid climate warming at the end of the last ice age, new research shows.
Understanding the relationship between volcanic activity, hypoxia and ice melt due to warming temperatures during the last ice age, which ended about 18,000 years ago, raises important questions about what might occur as the planet warms today.
“It is unknown right now whether volcanic eruptions will increase as the climate warms,” said the study’s lead author, Jianghui Du of ETH Zurich in Switzerland, who conducted the research as a doctoral student at Oregon State University’s College of Earth, Ocean, and Atmospheric Sciences.
“But we know that the remaining glaciers on volcanoes in the Pacific Ocean ring of fire are melting fast, and it will be important to include this ice loss in predictions of future eruptions, which would be risky for populated regions and could also make emerging hypoxic dead zones in the North Pacific worse.”
The study was published today in the journal Nature. The findings point to a systematic relationship between climate, glacier retreat, volcanic activity, biological productivity and deoxygenation of the ocean, said Alan Mix, an oceanographer and paleoclimatologist at Oregon State and a co-author of the paper.
“These surprising linkages between parts of the Earth we usually think of as separate highlight how interconnected the whole system really is,” he said. “Solving environmental problems, such as those we face in the ongoing climate crisis, demands that we look with open minds at the whole linked system and not just at isolated parts.”
The volcanic region in the Pacific Ocean is known as the ring of fire in part because it is one of the most active tectonic and volcanic regions of the world.
The timing of volcanic events in relation to the retreat of the Cordilleran Ice Sheet, which once covered large portions of western North America, suggests that the rapid melting of ice covering volcanoes in the region induced increased volcanic activity, Mix said.
“Ice cover to volcanoes is like a cork in a champagne bottle. Remove the icy cork and boom, the eruptions begin,” he said.
Past research had shown a few ash layers in sediment in the region, but Du’s chemical study, using deep-sea sediment cores from the Gulf of Alaska, revealed more traces of ash that were not visible to the eye.
Du catalogued and compared volcanic eruptions from areas that were covered in ice against those areas that were not ice-covered during the last ice age.
“We found a distinct pattern of many eruptions during warming and ice retreat in the areas where glaciers were present, and much less change in the frequency of eruptions outside the ice-covered zone, particularly in western North America,” Du said. “That provides strong evidence for the volcanic response to warming and ice retreat.”
The chemical fingerprints also showed a consistent pairing of volcanic ash and hypoxic events. The increase in volcanic ash likely fueled ocean productivity that ultimately created low-oxygen conditions.
Co-authors from Texas A&M University, Christina Belanger and Sharon, who uses only one name, examined a species of seafloor organisms called foraminifera and found that they closely tracked the volcanic ash input from the Gulf of Alaska. These organisms thrive under highly productive waters and can tolerate low oxygen conditions.
“Volcanic ash includes important trace nutrients for plankton, especially iron,” said co-author Brian Haley, a research professor at Oregon State.
“When the ash hits the ocean, the plant plankton gobble up that iron and bloom. This fertilization effect underscores a practical application of our work. Some have proposed fertilizing the North Pacific with iron to capture excess carbon dioxide from the atmosphere,” he said. “We show that the real world has effectively run that experiment in the past with volcanic iron, and the fertilization effect works and exports carbon to the deep sea. That’s good news. But there are some dangerous consequences because when that excess organic matter decomposes as it falls to the ocean depths, it consumes oxygen and creates dead zones.”
