Posts Tagged ‘global warming’

Every beachgoer can spot seaweed in the ocean or piling up on the beach, but Florida State University researchers working with colleagues in the United Kingdom have found that these slimy macroalgae play an important role in permanently removing carbon dioxide from the atmosphere.

Their work is published in the journal Ecological Monographs by the Ecological Society of America.

The researchers, who partnered with ecologists from Plymouth Marine Laboratory in the United Kingdom, investigated how seaweed absorbed carbon and processed it, trapping it in the seafloor.

“Seaweeds have been ignored in the ‘blue carbon’ storage literature in favor of seagrasses and mangroves, which physically trap carbon from sediments and their own biomass in root structures,” said Assistant Professor of Biological Science Sophie McCoy. “Macroalgae are also often overlooked by oceanographers who study the carbon cycle, as their high productivity occurs close to shore and has been thought to stay and cycle locally.”

In designing the study, researchers suspected that the high productivity and huge amount of seasonal biomass of annual algae would provide carbon subsidies farther offshore than typically considered, and that these subsidies would be important to benthic food webs there.

That was exactly what they found. They also discovered that this was the process that leads to the burial of seaweed carbon in ocean sediments.

Blue carbon is the carbon captured in marine systems both through photosynthesis and then by trapping it in the seafloor. Researchers sequenced environmental DNA and modeled stable isotope data for over a year off the coast of Plymouth, England. Through this, they found that seaweed debris was an important part of the food web for marine organisms and that much of that debris was ultimately stored in sediments or entered the food web on the seafloor.

Jeroen Ingels, a researcher at the FSU Coastal and Marine Laboratory who conducted the meiofauna work for the study, said the research not only explains seaweed’s role in the food web, but it also shows that human activities that affect seaweed and the sea floor are important to monitor.

“The human activities that are impacting macroalgae and sediment habitats and their interstitial animals are undermining the potential for these systems to mitigate climate change by affecting their potential to take up and cycle carbon,” he said. “The study really illustrates in a new way how seaweed and subsequently benthic animals can contribute in a significant way to blue carbon.”

The team found that about 8.75 grams of macroalgae carbon are trapped per square meter of sediment each year.

Ana M. Queiros, a scientist at Plymouth Marine Laboratory and the paper’s lead author, said these first measurements of seaweed carbon trapped in the sediment gives scientists more information to help them develop sustainable environmental practices.

“They tell us that the global extent of blue carbon-meaningful marine habitats could be much wider than we previously thought,” she said. “Identifying these areas and promoting their management will let us capitalize on the full potential of the ocean’s blue carbon towards the stabilization of the global climate system.”

Journal Reference:

Ana Moura Queirós, Nicholas Stephens, Stephen Widdicombe, Karen Tait, Sophie J. McCoy, Jeroen Ingels, Saskia Rühl, Ruth Airs, Amanda Beesley, Giorgia Carnovale, Pierre Cazenave, Sarah Dashfield, Er Hua, Mark Jones, Penelope Lindeque, Caroline L. McNeill, Joana Nunes, Helen Parry, Christine Pascoe, Claire Widdicombe, Tim Smyth, Angus Atkinson, Dorte Krause‐Jensen, Paul J. Somerfield. Connected macroalgal‐sediment systems: blue carbon and food webs in the deep coastal ocean. Ecological Monographs, 2019; e01366 DOI: 10.1002/ecm.1366

https://www.sciencedaily.com/releases/2019/06/190603124721.htm

Thanks to Lynn and Bill Penland for bringing this to the It’s Interesting community.

There is no precedent in contemporary weather records for the kinds of droughts the country’s West will face, if greenhouse gas emissions stay on course, a NASA study said.

No precedent even in the past 1,000 years.

The feared droughts would cover most of the western half of the United States — the Central Plains and the Southwest.

Those regions have suffered severe drought in recent years. But it doesn’t compare in the slightest to the ‘megadroughts’ likely to hit them before the century is over due to global warming.
These will be epochal, worthy of a chapter in Earth’s natural history.

Even if emissions drop moderately, droughts in those regions will get much worse than they are now, NASA said.

The space agency’s study conjures visions of the sun scorching cracked earth that is baked dry of moisture for feet below the surface, across vast landscapes, for decades. Great lake reservoirs could dwindle to ponds, leaving cities to ration water to residents who haven’t fled east.

“Our projections for what we are seeing is that, with climate change, many of these types of droughts will likely last for 20, 30, even 40 years,” said NASA climate scientist Ben Cook.

That’s worse and longer than the historic Dust Bowl of the 1930s, when “black blizzards” — towering, blustery dust walls — buried Southern Plains homes, buggies and barns in dirt dunes.

It lasted about 10 years. Though long, it was within the framework of a contemporary natural drought.

To find something almost as extreme as what looms, one must go back to Medieval times.

Nestled in the shade of Southwestern mountain rock, earthen Ancestral Pueblo housing offers a foreshadowing. The tight, lively villages emptied out in the 13th century’s Great Drought that lasted more than 30 years.

No water. No crops. Starvation drove populations out to the east and south.

If NASA’s worst case scenario plays out, what’s to come could be worse.

Its computations are based on greenhouse gas emissions continuing on their current course. And they produce an 80% chance of at least one drought that could last for decades.

One “even exceeding the duration of the long term intense ‘megadroughts’ that characterized the really arid time period known as the Medieval Climate Anomaly,” Cook said.

That was a period of heightened global temperatures that lasted from about 1100 to 1300 — when those Ancestral Pueblos dispersed. Global average temperatures are already higher now than they were then, the study said.

The NASA team’s study was very data heavy.

It examined past wet and dry periods using tree rings going back 1,000 years and compared them with soil moisture from 17 climate models, NASA said in the study published in Science Advances.

Scientists used super computers to calculate the models forward along the lines of human induced global warming scenarios. The models all showed a much drier planet.

Some Southwestern areas that are currently drought-stricken are filling up with more people, creating more demand for water while reservoirs are already strained.

The predicted megadroughts will wrack water supplies much harder, NASA Goddard Space Flight Center said.

“These droughts really represent events that nobody in the history of the United States has ever had to deal with,” Cook said.

Compared with the last millennium, the dryness will be unprecedented. Adapting to it will be tough.

http://www.cnn.com/2015/02/14/us/nasa-study-western-megadrought/index.html

Climate change could affect the ratio of human males to human females that are born in some countries, a new study from Japan suggests. The researchers found that male fetuses may be particularly vulnerable to the effects of climate change.

Since the 1970s, temperature fluctuations from the norm have become more common in Japan, and at the same time there has been an increase in the deaths of male fetuses, relative to the number of deaths of female fetuses in that country, according to the study.

Over this period, the ratio of male to female babies born in the country has been decreasing, meaning there have been fewer and fewer male babies born relative to the number of female babies born.

http://www.livescience.com/48070-male-fetus-climate-change.html