EF9C. Stay Current—How Does Energy Flow in Living Systems?

2024-10-30. Saharan Dust Carries Iron That Feeds Life in the Distant Ocean. By Katherine Bourzac, Eos/AGU. Excerpt: Windblown iron carried on dust particles from the Sahara travels long distances. The critical nutrient is ferried to plants in the Amazon and to phytoplankton in the Atlantic Ocean and elsewhere. But much of this iron is initially locked up in molecules that are not bioavailable—cells simply can’t use it. New research published in Frontiers in Marine Science shows that the farther this iron travels on windblown dust, the more bioavailable it becomes because of chemical reactions it undergoes while in the atmosphere. Iron is essential for some of life’s most basic processes, playing a key role in biomolecules responsible for photosynthesis, DNA repair, and more. It’s a key constraint on the growth of phytoplankton, the bedrock of ocean ecosystems and a major driver of the planet’s carbon cycle…. Full article at https://eos.org/articles/saharan-dust-carries-iron-that-feeds-life-in-the-distant-ocean.

2021-04-22. Microbes are siphoning massive amounts of carbon from Earth’s tectonic plates. By Raleigh McElvery, Science Magazine. Excerpt: A few kilometers below our feet lies a hidden world of microbes whose chemical reactions are shaping the long-term habitability of the planet. A new study suggests some of these microbes are siphoning off massive amounts of carbon as it enters Earth, using it to fuel their own sunless ecosystems. …Researchers say the microbes represent an overlooked factor in efforts to balance Earth’s deep carbon cycle. …These microbes could be sequestering 2% to 22% of the carbon previously thought to reach the deep mantle, the researchers report today in Nature Geoscience. … [https://www.sciencemag.org/news/2021/04/microbes-are-siphoning-massive-amounts-carbon-earth-s-tectonic-plates] 

2016-07-28. How Irrigation in Asia Affects Rainfall in Africa. By Sarah Stanley, EoS Earth and Space News, AGU. Excerpt: Agricultural irrigation is so widespread that it accounts for about 4% of the total evapotranspiration of water from Earth’s surface. Scientists have known for some time that water vapor from irrigation affects regional and global climates. Now, for the first time, researchers have shown that irrigation in one region can directly affect the climate of another region thousands of kilometers away. De Vrese et al. used the Max Planck Institute for Meteorology’s Earth System Model to simulate the fate and impact of water used for irrigation in South Asia from 1979 to 1999. In the simulations, early spring winds carried water vapor from irrigation in South Asia across the Arabian Sea and into East Africa, increasing humidity there. By late spring, when irrigation in the Middle East, Turkmenistan, and Afghanistan is in full swing, wind transported water vapor into Africa, increasing humidity as far west as Nigeria. …The simulations show that water vapor transport from South Asian irrigation increases springtime rainfall in Africa by up to 1 millimeter per day. Increased rainfall and cloud cover may cool the surface by up to 0.5 kelvin. In the arid parts of East Africa, as much as 40% of the total yearly rainfall may be attributed to irrigation in Asia….  https://eos.org/research-spotlights/how-irrigation-in-asia-affects-rainfall-in-africa

2015-06-22. Amazon Rain Forest Nourished by African Dust. By Terri Cook, EOS publication of AGU. Excerpt: New satellite data highlight the important role African dust plays in maintaining the rain forest’s long-term health. The productivity of the Amazon rain forest, which plays a crucial role in regulating Earth’s climate, is limited by the availability of nutrients, especially phosphorous. Because water runoff keeps depleting this key nutrient from the basin’s old and low-phosphorus soils, previous studies have suggested the Amazon’s long-term productivity must depend upon dust transported from a distance source such as the Sahara. This foreign source of phosphorous, however, is not well quantified, and large discrepancies exist between current measurements and model estimates. To resolve these discrepancies, Yu et al. published the first multiyear (2007–2013) satellite-based estimate of dust deposition in the Amazon Basin using three-dimensional (3-D) aerosol measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite…. https://eos.org/research-spotlights/amazon-rain-forest-nourished-by-african-dust

2009 October 15. Deep-Sea Microbes May Answer Long-Standing Question About Earth’s Nitrogen Cycle. NSF Release 09-201.Excerpt: …Although lightning, combustion, and other non-biological processes can create reduced nitrogen, far more is generated by nitrogen-fixing microorganisms such as bacteria, in particular, photosynthetic aquatic cyanobacteria. These organisms produce the bulk of the nitrogen available to living things in the ocean.
When researchers add up all known sources of fixed nitrogen–biological and otherwise–in the global nitrogen cycle, and compare it to the sinks (biological uptake for growth and energy), they come up short. More nitrogen appears to be used than is being made. The “nitrogen budget,” in effect, does not balance.
The question has been whether the nitrogen cycle is out of balance, or whether the known inventories of sources and sinks are incomplete, says Victoria Orphan, a geobiologist at Caltech.
Orphan, along with Caltech graduate student Anne Dekas and Caltech postdoctoral researcher Rachel Poretsky, suggest the answer is, at least in part, an incomplete catalogue of the sources of fixed nitrogen.
…The team studied ocean sediment samples in methane cold seeps 20 miles off northern California at a depth of 1,800 feet. The area, known as the Eel River Basin, is in a region that supports high levels of natural methane seepage at the sea-floor.
… tiny microbial conglomerations … averaging 500 cells each, consist of two types of anaerobic microorganisms living in a unique symbiotic relationship fueled by methane. … a bacterium … reduces the chemical sulfate into sulfide …to generate energy. The second is a methane-oxidizing archaeon …Working together, these two symbionts are responsible for consuming the majority of the naturally-released methane in the deep sea.
Although these symbiotic associations themselves are not new–the conglomerations were found about a decade ago–the scientists discovered something unexpected: the methane-consuming archaea were actively fixing nitrogen, and sharing it with their bacterial neighbors.
This is the first time nitrogen fixation has been documented in methane-oxidizing archaea, say the scientists….

2009 May 28. Serving Suggestion. By Karen Solomon, OnEarth (NRDC ISSUE: Summer 2009) Excerpt: With Sasha and Malia growing arugula in the White House garden, and with more and more farmers’ markets on our streets, it seems shocking that prefab Tater Tots and canned fruit cocktail should continue to rule the lunchrooms of our public schools.
Until October 2005, the Berkeley Unified School District in California was no exception. Its 9,000 students were served the usual highly processed, highly subsidized heat-and-serve dreck that passed for the noontime meal. That is, until Ann Cooper became director of nutrition services, making a radical shift from chicken nuggets to real chicken, fresh produce instead of ketchup packets, and whole-grain, real bean and cheese nachos with not a can of cheese sauce in sight. Now Cooper, who first made a name for herself on the celebrity-chef circuit, is taking her mission and her menu to school cafeterias nationwide.
“High-fat, high-sugar, high-salt diets with very few fruits and vegetables and no whole grains will lead to a generation of kids who, for the first time, will die at a younger age than their parents,” says Cooper, citing Centers for Disease Control statistics that a third of our nation’s children are overweight or obese. Because minority students are most affected by what’s on the daily cafeteria tray, real lunch reform is “the social justice issue of our time,” Cooper says. “We can’t spend another dollar per day per child to feed them healthy food?” she yells in exasperation. “We can either pay for lifelong wellness now, or pay later for a tsunami of diabetes. And these kids can’t learn if they’re not well nourished.”…

2008 July 18. Saharan dust storms sustain life in Atlantic Ocean. Eureka Alert. Excerpt: Research at the University of Liverpool has found how Saharan dust storms help sustain life over extensive regions of the North Atlantic Ocean.
Working aboard research vessels in the Atlantic, scientists mapped the distribution of nutrients including phosphorous and nitrogen and investigated how organisms such as phytoplankton are sustained in areas with low nutrient levels.
They found that plants are able to grow in these regions because they are able to take advantage of iron minerals in Saharan dust storms. This allows them to use organic or ‘recycled’ material from dead or decaying plants when nutrients such as phosphorous – an essential component of DNA – in the ocean are low…
“These findings are important because plant life cycles are essential in maintaining the balance of gases in our atmosphere. In looking at how plants survive in this area, we have shown how the Atlantic is able to draw down carbon dioxide from the atmosphere through the growth of photosynthesising plants.”

2005 April 21. NASA RELEASE: 05-100. NASA Study Finds Snow Melt Causes Large Ocean Plant Blooms. A NASA funded study has found a decline in winter and spring snow cover over Southwest Asia and the Himalayan mountain range is creating conditions for more widespread blooms of ocean plants in the Arabian Sea. The decrease in snow cover has led to greater differences in both temperature and pressure systems between the Indian subcontinent and the Arabian Sea. The pressure differences generate monsoon winds that mix the ocean water in the Western Arabian Sea. This mixing leads to better growing conditions for tiny, free-floating ocean plants called phytoplankton. …When winter and spring snow cover is low over Eurasia, the amount of solar energy reflected back into the atmosphere is less. A decline in the amount of snow cover means less of the sun’s energy goes towards melting of snow and evaporation of wet soil. As a result the land mass heats up more in summer creating a larger temperature difference between the water of the Arabian Sea and the Indian subcontinent landmass. The temperature difference is responsible for a disparity in pressure over land and sea, creating a low pressure system over the Indian subcontinent and a high pressure system over the Arabian Sea. This difference in pressure causes winds to blow from the Southwest Arabian Sea bringing annual rainfall to the subcontinent from June to September. In the Western Arabian Sea, these winds also cause upwelling of cooler nutrient-rich water, creating ideal conditions for phytoplankton to bloom every year during summer. … while large blooms of phytoplankton can enhance fisheries, exceptionally large blooms could be detrimental to the ecosystem. Increases in phytoplankton amounts can lead to oxygen depletion in the water column and eventually to a decline in fish populations. More info.