Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a phytoplankton bloom off the coast of Argentina, which became visible in satellite images as summer approached in the southern hemisphere.



“The color of the ocean provides us with important information about phytoplankton, the health of the ocean, and the global climate,” said Ivona Cetinić, the science lead of ocean biogeochemistry for an upcoming NASA satellite called the Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission.



Cetinić said that the color of the swirls can tell us something about the type of plankton present in the bloom. She explained that it is difficult to tell immediately the types of phytoplankton present.



Identifying the different types of phytoplankton present in seawater can help scientists understand more about carbon and nutrient cycling in the ocean. While satellites still have some limitations for understanding ocean ecology, some of these limitations could soon be resolved, said Cetinić.



“PACE is hyperspectral, which means it will be able to see many different hues and will help us tease apart which types of phytoplankton are present. It will also help us quickly identify and forecast harmful algal blooms."&nbsp;



Cetinić said that moving to PACE to understand ocean ecology will be like "switching from a flip phone to the latest smart phone."



The image was captured on November 21, 2022 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.&nbsp;



Image Credit: NASA Earth Observatory



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Plankton colors provide information about ocean health

Today's Image of the Day from NASA Earth Observatory features...

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features brightly colored sediment swirls along the coast of the Yucatan Peninsula in Mexico.&nbsp;



The Yucatan Peninsula was transformed 66 million years ago, when an asteroid or comet about 10 miles wide smashed into Earth.&nbsp;



The catastrophic impact triggered tsunamis, wildfires, and released a giant dust cloud that blocked the Sun and abruptly altered the climate. This collision ultimately killed at least three-fourths of life on Earth, including the dinosaurs.



The impact crater can be found near the town of Chicxulub on the northern coast of the Yucatán Peninsula. The Chicxulub crater is very well-preserved.



According to NASA, in the millions of years since the impact, the crater has been buried in thick layers of limestone. When the limestone erodes, the sediments wash out onto the Yucatán Shelf.



The image was captured on October 31, 2021 by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.



Image Credit: NASA Earth Observatory&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Bright sediment swirls surrounding the Yucatán Peninsula

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features a gray winter haze over northeastern China on January 3, 2022. The haze represents air pollution and unhealthy air quality.&nbsp;



On this day, based on data from The World Air Quality Project, several sensors in the region detected levels of fine particulate matter (PM2.5) in the very unhealthy and hazardous range. This indicates that fine particulate levels were several times higher than the World Health Organization’s recommended limit.



Despite improvements in recent years, China still produces enough air pollution to regularly darken skies in some areas, reports NASA. The gray smog in the photo is so thick that it blocks out key features of the landscape below, such as lakes and farmland.&nbsp;



According to NASA, one likely component of the gray haze is nitrate particles. A recent study led by Harvard University revealed that levels of nitrates have remained high over China, even as the country's greenhouse gas emissions have been reduced.&nbsp;



“Nitrate is now the principal component of Beijing winter haze pollution, contributing to 30-40 percent of PM2.5 mass during winter haze days,” wrote the study authors. “There is an urgent need to better understand why nitrate is not decreasing.”



The image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.&nbsp;



Image Credit: NASA Earth Observatory&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Gray winter haze over northeastern China

Today's Image of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> features Noirmoutier, a small tidal island on the western coast of France. The photograph, which was taken by an astronaut onboard the International Space Station (ISS), captures the northwestern portion of the island.&nbsp;



According to NASA, the photo was taken at approximately 1:00 p.m. local time, when the low tide exposes mudflats, salt marshes, and sand dunes.



Noirmoutier is famous for its salt and oysters. In the summer months, the locals collect salt from a series of channels, while oyster farming is widespread in the bay.



Image Credit: NASA Earth Observatory&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Noirmoutier on the western coast of France

Spiral Snapshot

Today's Image of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the barred spiral galaxy Messier 91 (M91), which is located about 55 million light-years from Earth in the <a href="https://www.earth.com/image/spiral-galaxy-in-the-constellation-fornax/">constellation</a> Coma Berenices.



According to NASA, M91 is one of over 1,000 galaxies that make up the Virgo cluster, a group of galaxies that are gravitationally bound to one. The photo was captured by the Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope.&nbsp;



"While M91’s prominent bar makes for a spectacular galactic portrait, it also hides an astronomical monstrosity," reports ESA. "Like our own galaxy, M91 contains a supermassive black hole at its centre. A 2009 study using archival Hubble data found that this central black hole weighs somewhere between 9.6 and 38 million times as much as the Sun."



Using data from the archives, astronomers could weigh M91’s central black hole. But ESA explains that the latest observation is part of an effort to build a treasure trove of astronomical data exploring the connections between young stars and the clouds of cold gas in which they form.&nbsp;



Image Credit: ESA



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Spiral galaxy M91 in the constellation Coma Berenices

Today's Image of the Day from the European Space Agency...

A new study led by <a href="https://home.dartmouth.edu/">Dartmouth College</a> may finally settle a long-standing debate over what caused five major mass extinctions, including the event that ultimately wiped out the <a href="https://www.earth.com/news/new-impact-crater-dates-back-to-the-end-of-the-dinosaurs/">dinosaurs</a>. While some scientists argue that mass extinctions were the result of comet or asteroid impacts, the new study supports the theory that volcanic activity was the key driver of the biggest extinction events in Earth's history.



According to the researchers, four of the five mass extinctions are contemporaneous with a type of volcanic outpouring called a flood basalt. These eruptions are known to flood vast areas, even entire continents, leaving behind what scientists refer to as “large igneous provinces.”&nbsp;



To fit into this category, a large igneous province must contain at least 100,000 cubic kilometers of magma.&nbsp;



As a point of reference, the 1980 eruption of Mount St. Helens involved less than one cubic kilometer of magma. Most of the volcanoes represented in the study erupted on the order of a million times more lava than that, noted the researchers.



“The large step-like areas of igneous rock from these big volcanic eruptions seem to line up in time with mass extinctions and other significant climatic and environmental events,” said study lead author Theodore Green.



For example, the Deccan Traps is a large igneous province in west-central India that dates back to the time when dinosaurs were wiped out 66 million years ago, which is also the same time that the Chicxulub impact crater was formed.&nbsp;



“All other theories that attempted to explain what killed the dinosaurs, including volcanism, got steamrolled when the Chicxulub impact crater was discovered,” said study co-author Professor Brenhin Keller. However, he noted that there's very little evidence of similar impact events that coincide with the other mass extinctions despite decades of exploration.



In collaboration with study co-author Professor Paul Renne, the researchers set out to quantify the apparent link between volcanic eruptions and extinctions. They discovered that this link was far greater than it would be by random chance.&nbsp;



“While it is difficult to determine if a particular volcanic outburst caused one particular mass extinction, our results make it hard to ignore the role of volcanism in extinction,” said Professor Keller.&nbsp;



“Our results indicate that in all likelihood there would have been a mass extinction at the Cretaceous tertiary boundary of some significant magnitude, regardless of whether there was an impact or not, which can be shown more quantitatively now,” said Professor Renne. “The fact that there was an impact undoubtedly made things worse.”



Green explained that the eruption rate of the Deccan Traps in India suggests that the stage was set for widespread extinction even without the asteroid. The impact was the double whammy that loudly sounded the death knell for the dinosaurs, he said.



“While the total amount of carbon dioxide being released into the atmosphere in modern climate change is still very much smaller than the amount emitted by a large igneous province, thankfully, we’re emitting it very fast, which is reason to be concerned," said Professor Keller.



Green pointed out that carbon dioxide emissions are uncomfortably similar to the rate of the environmentally impactful flood basalts they studied. He said that this places climate change in the framework of historical periods of environmental catastrophe.



The study is published in the journal <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>.



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Volcanoes were the key driver of Earth's mass extinctions

A new study led by Dartmouth College may finally settle...

Rapid climate change is placing significant stress on many of our planet’s plants and animals. In fact, many scientists argue that we are currently in the midst of the sixth mass extinction, with entire species disappearing up 10,000 times faster than before the industrial era. However, experts have been uncertain which ecosystems and species are most at risk.&nbsp;



According to a new study led by the <a href="https://www.umass.edu/">University of Massachusetts, Amherst</a>, the focus on species-level risk obscures a wide variability in temperature tolerance, even within the same species. Moreover, this variability appears to be greater for marine species than for terrestrial ones. These findings have important implications for <a href="https://www.earth.com/news/wildlife-conservation-can-help-stabilize-the-climate/">conservation</a> and management practices and offer a window of hope in our effort to adapt to a rapidly warming world.



“One of the most important biological discoveries in the last century is that evolution can happen much more quickly than previously thought,” said study senior author&nbsp;Brian Cheng, a professor of Marine Ecology at UMass Amherst. “One of the implications of this is that different populations of the exact same species can adapt to their local environments more readily than traditional biology would have thought possible.”



By conducting a metanalysis of 90 previous studies, the scientists collected data on 61 animal species, and constructed a set of “upper thermal limits,” or specific temperatures above which each species could not survive. Yet, by zooming in further and identifying 305 distinct populations drawn from these species, the experts were surprised to find that different populations of the same species often had highly different thermal limits, particularly in the case of marine wildlife.&nbsp;



However, although terrestrial species appear to exhibit far more homogeneity in their thermal limits - and thus may be more sensitive to rising temperatures - they can nevertheless take advantage on microclimates to avoid extreme temperatures and cool down, such as by moving into shady areas.



These discoveries suggests that some populations have evolved different abilities to tolerate high temperatures. Thus, a key aspect of conservation practices would be to keep different populations of the same species connected, in order for those that have adapted to higher temperatures to pass this advantage on to populations with lower thermal limits.



Taken together, these findings show that a one-size-fits-all species-focused approach to conservation and management will most likely not work. Instead, in order to predict their vulnerability to changing conditions, we have to understand how populations have adapted to their local environments. “The glimmer of hope here is that with conservation policies tailored to individual populations, we can buy them time to adapt to the warming world,” Cheng concluded.



The study is published in the journal <a href="http://dx.doi.org/10.1038/s41558-022-01534-y">Nature Climate Change</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Focus on populations, not species, to protect nature

Rapid climate change is placing significant stress on many of...

Scientists have long known that salt marshes are a major <a href="https://www.earth.com/news/how-will-earths-new-lakes-affect-the-carbon-budget/">carbon</a> sink and can be of critical help in carbon sequestration efforts. However, they are also highly dynamic ecosystems that constantly change with seasons and tides. By focusing on the Sage Lot Pond on Cape Cod, a new study led by the <a href="https://www.mbl.edu/research/research-centers/ecosystems-center">Marine Biological Laboratory (MBL) Ecosystems Center</a> has now investigated how seasonal cycles and the ocean dynamics affect the amount of carbon stored in New England marshes.



“In our recent study, we asked: how does marsh respiration (the conversion of organic carbon to carbon dioxide) vary as a function of temperature, both of air and sediment? This can help us understand how climate change, particularly warming, alters respiration rates in a marsh,” said study lead author Joanna Carrey, an associate professor of Environmental Science at <a href="https://www.babson.edu/">Babson College</a>, who conducted this research during a postdoctoral fellowship at MBL.&nbsp;



The scientists examined gas exchange from the Sage Lot Pond marsh system over 16 months between 2014 and 2016, by installing static gas chambers in six plots, ranging from high elevation marsh (which is flooded by tides just a few days per month) to low elevation marsh (flooded twice daily). The chambers were used to record the amount of carbon dioxide released in the atmosphere each second for four minutes straight.



The analysis revealed that each degree of warming correlated with an exponential increase in carbon dioxide emissions. “But what was surprising is that we found higher temperature sensitivity in the low marsh habitat. That means for each degree of warming, there was significantly more carbon dioxide released from the marsh at lower elevation relative to the high-marsh habitat,” Carey&nbsp;explained.



The fact that low marshes stored more carbon had seemed a beneficial thing for natural carbon sequestration, particularly since sea-level rise is resulting in the conversion of high-marsh to low-marsh environments. However, this study shows that, as the world continues to warm, these benefits may be diminished, since CO2 is also released there at a significantly higher rate with increasing temperatures.



In addition, the researchers found that the Sage Lot marsh environment loses much more respired carbon to the ocean via ebbing tides than it does directly through vertical fluxes to the air. Thus, although some of the respired carbon will be returned to the atmosphere as a CO2 flux from the sea, a part of it most likely remains dissolved in the ocean for an extended period – maybe even thousands of years – thereby enhancing the carbon sequestration value of salt marshes.



In future research, the scientists aim to study also nitrogen loads and emissions by using the same methods, as well as to examine how their findings might extend to other marshes.



The study is published in the journal <a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2022JG006832">Journal of Geophysical Research: Biogeosciences</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Low marshes emit more CO2 as temperatures rise

Scientists have long known that salt marshes are a major...

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Today’s Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> describes a wearable sensor to help monitor the water levels of plants.&nbsp;



When plants are in need of water, there are not always obvious signals. Plant leaves do not turn brown or shrivel until most of the water is gone.&nbsp;



The new system is designed to detect water loss earlier. According to ACS, the system can wirelessly transmit data to a smartphone app, allowing for remote management of drought stress in gardens and crops.



&#8220;Impedimetric wearable sensors are a promising strategy for determining the loss of water content (LWC) from leaves because they can afford on-site and nondestructive quantification of cellular water from a single measurement,&#8221; explained the study authors.&nbsp;



&#8220;Because the water content is a key marker of leaf health, monitoring of the LWC can lend key insights into daily practice in precision agriculture, toxicity studies, and the development of agricultural inputs.&#8221;



The experts have published their research in the ACS journal <a href="https://pubs.acs.org/journal/aamick">Applied Materials &amp; Interfaces</a>.



Video Credit: ACS



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Plant sensor can remotely track water levels