ANN ARBOR — University of Michigan researchers and their University of Hawaii colleagues say they’ve solved the longstanding mystery of how mercury gets into open-ocean fish, and their findings suggest that levels of the toxin in Pacific Ocean fish will likely rise in coming decades.
Using isotopic measurement techniques developed at U-M, the researchers determined that up to 80 percent of the toxic form of mercury, called methylmercury, found in the tissues of deep-feeding North Pacific Ocean fish is produced deep in the ocean, most likely by bacteria clinging to sinking bits of organic matter. (more…)
Under the microscope, they look like they could be from another planet, but these microscopic organisms inhabit the depths of our oceans in nearly infinite numbers.
To begin to identify where, when, and how much oceanic plankton can be found around the globe, a group of international researchers have compiled the first ever global atlas cataloguing marine plankton ranging in size from bacteria to jellyfish. The atlas was published on July 19, 2013, in a special issue of the journal Earth System Science Data. (more…)
Berkeley Lab scientists image cell-to-cell connections between soil microbes
The next time your Facebook stream is filled with cat videos, think about Myxococcus xanthus.The single-cell soil bacterium also uses a social network. But forget silly distractions. M. xanthus relies on its connections to avoid getting eaten and to score its next meal.
That’s the latest insight from a team of Berkeley Lab scientists. Using several imaging techniques, they saw for the first time that M. xanthus cells are connected by a network of chain-like membranes. (more…)
Environmental conditions have a much stronger influence on the mix of microbes living in various parts of your body than does competition between species. Instead of excluding each other, microbes that fiercely compete for similar resources are more likely to cohabit in the same individual.
This phenomenon was discovered in a recent study of the human microbiome – the vast collection of our resident bacteria, fungi, and other tiny organisms. (more…)
In a twist on “survival of the fittest,” researchers have discovered that evolution is driven not by a single beneficial mutation but rather by a group of mutations, including ones called “genetic hitchhikers” that are simply along for the ride. These hitchhikers are mutations that do not appear to have a role in contributing to an organism’s fitness and therefore its evolution, yet may play an important role down the road.
Researchers from Princeton University found in a study of 1,000 generations of adaptation in 40 yeast populations that about five to seven specific mutations, rather than just a one, are needed for an organism to succeed. The knowledge of how mutations drive evolution can inform our understanding of how tumors resist chemotherapeutics and how bacteria evolve resistance to antibiotics. The study was published July 21 in the journal Nature. (more…)
The deep biosphere—the realm of sediments far below the seafloor—harbors a vast ecosystem of bacteria, archaea, and fungi that are actively metabolizing, proliferating, and moving, according a new study by scientists at Woods Hole Oceanographic Institution (WHOI) and the University of Delaware (UD).
“This is the first molecular evidence for active cell division in the deep biosphere,” says WHOI postdoctoral investigator Bill Orsi, who was the lead author on the study. Previous studies and models had suggested cells were alive, but whether the cells were actually dividing or not had remained elusive. (more…)
New findings overturn understanding of light-dependent environmental oxidants
Breathing oxygen… can be hazardous to your health?
Indeed, our bodies aren’t perfect. They make mistakes, among them producing toxic chemicals, called oxidants, in cells. We fight these oxidants naturally, and by eating foods rich in antioxidants such as blueberries and dark chocolate.
All forms of life that breathe oxygen—even ones that can’t be seen with the naked eye, such as bacteria—must fight oxidants to live. (more…)
Understanding microbe communities could improve wetland wastewater treatment systems
COLUMBIA, Mo. – Wetlands serve as the Earth’s kidneys. They filter and clean people’s water supplies while serving as important habitat for many species, including iconic species like cattails, cranes and alligators. Conventional ecosystem health assessments have focused on populations of these larger species. However, the tiny, unseen creatures in the wetlands provided crucial indicators of the ecosystems’ health in a study by University of Missouri Associate Professor of Engineering Zhiqiang Hu and his team. Using analysis of the microbiological health of wetlands is cheaper and faster than traditional assessments, and could lead to improvements in harnessing natural processes to filter humans’ wastewater.
“During road and building construction, engineers must sacrifice wetlands to development, but laws dictate that these lost wetlands be compensated for by establishing a wetland somewhere else,” said Hu. “Our research could be applied to both monitor the success of these compensation wetlands and guide conservationists in inoculating new engineered ecosystems with the correct types of microorganisms.” (more…)
