Galapagos finches and marine bacteria, new research


This 2014 video is called The adaptive radiation of Darwin’s Finches.

From the Max Planck Institute for Marine Microbiology in Germany:

Sweet beaks: What Galapagos finches and marine bacteria have in common

February 19, 2020

Summary: Ecological niches are a concept well known from higher animals. Apparently, bacteria act accordingly. Researchers have found that marine Polaribacter bacteria find their ecological niche by specializing on their favorite sugar.

The variety of finch species on the remote Galapagos Islands is the most prominent example for Charles Darwin‘s and Alfred R. Wallace‘s theory of evolution through natural selection. Galapagos finch species have developed distinct beak sizes and shapes and thereby have adapted to different food sources. This exemplifies how even closely related species can effectively make use of available resources, avoid competition and thus co-occur in the same habitat.

A bloom with great effect

This principle is not limited to macrofauna. It also applies in the realm of marine microbes, the scientists from Bremen now show. Satellite photos taken from coastal areas during warm seasons often show that the ocean is green rather than blue. This color originates from immense numbers of microscopic marine algae — so-called algal blooms. Such blooms are transient: At some point, all nutrients are depleted and predators like protists and viruses have taken their share. The ensuing mass mortality of the algae leads to the release of large quantities of organic matter into the seawater, including algal polysaccharides. These algal sugars are one of the main food sources for heterotrophic marine bacteria.

Tiny niches for tiny organisms

Scientists at the Max Planck Institute for Marine Microbiology in Bremen, Germany, have investigated the bacterial response to spring algal blooms off the island of Heligoland in the German Bight (southern North Sea) for more than a decade. A close-knit microbial community is recurrently abundant during spring blooms in most years. One of the most prominent community members is Polaribacter, a genus of the Flavobacteriia class. From 2009 to 2012, the scientists investigated Polaribacter abundances during spring blooms and identified co-occurring closely related but distinct clades. “We found that these Polaribacter clades are pretty picky when it comes to sugar,” reports Burak Avci from the Max Planck Institute for Marine Microbiology. “Or, scientifically spoken: They have rather distinct niches with respect to algal polysaccharides.”

This is also reflected in the timing of the clade’s occurrence. Different clades tended to show up at different bloom stages. “One clade of presumed first responders is characterized by small genomes with a pronounced protein but limited sugar degradation capacity. In contrast, another clade of presumed late responders has larger genomes and the capacity to utilize more complex polysaccharides,” Avci continues. Another clade seems to be tied to presence of a specific algae (genus Chattonella). It is characterized by large genomes and has the most diverse sugar menu of all investigated Polaribacter clades.

Ecological significance

Like Galapagos finches, these results exemplify how also closely-related clades of marine bacteria (here Polaribacter) can forgo direct competition by partitioning available resources (here polysaccharides). “One of the fundamental questions in microbial ecology is which factors shape the composition of a given microbial community. Studies as this one advance our understanding of the principles that govern microbial community composition in such dynamic environments,” Avci concludes. This might be especially relevant for bacteria degrading algal blooms, which are an essential part of the global carbon cycle and might become more abundant following increased anthropogenic nutrient input into the oceans and global warming.

Humans making Antarctic birds sick


This 2013 video says about itself:

Animals in the Antarctic Ice

The wildlife of Antarctica are extremophiles, having to adapt to the dryness, low temperatures, and high exposure common in Antartica. The extreme weather of the interior contrasts to the relatively mild conditions on the Antarctic Peninsula and the Subantarctic islands, which have warmer temperatures and more liquid water. Much of the ocean around the mainland is covered by sea ice. The oceans themselves are a more stable environment for life, both in the water column and on the seabed.

From the University of Barcelona in Spain:

The fauna in the Antarctica is threatened by pathogens humans spread in polar latitudes

When the human species infects other living beings

December 10, 2018

Summary: The fauna in the Antarctica could be in danger due the pathogens humans spread in places and research stations in the southern ocean.

The new study, which detected bacteria from humans in the genus Salmonella and Campylobacter in Antarctic and Subantarctic marine birds, reveals the fragility of polar ecosystems and warns about the risk of massive deaths and extinctions of local fauna populations due pathogens.

Reverse zoonosis: when the human species infects other living beings

Explorers, whalers, scientists -and lately, tourists-, are examples of human collectives that moved to the furthest regions of the planet. Some studies have claimed for years that there had been cases of reverse zoonosis, that is, infections humans give to other living beings. Despite some previous signs, scientific studies on zoonotic agents in the Antarctic and Subantarctic areas have been fragmented. Therefore, evidence is spread and not completely convincing in this field.

The new study, published in the journal Science of the Total Environment, studies the potential transmission of bacteria from humans to marine bird populations in four areas of the Antarctic and Subantarctic ecosystems. “Chronology and potential pathways for reverse zoonosis in these ecosystems are complex and difficult to study, but it seems they can be clearly related to the proximity of the fauna to inhabited areas and the presence of research stations”, says Professor Jacob González-Solís, from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB and IRBio.

Antibiotic-resistant bacteria in polar ecosystems

The study confirms the first evidence of reverse zoonosis related to the presence of human-origin bacteria Salmonella and Campylobacter in polar fauna. One of the warning signs was, in particular, the identification of Campylobacter strains, which are resistant to ciprofloxacin and enrofloxacin (common antibiotics in medicine and veterinary).

“Finding common Campylobacter genotypes in human species or livestock was the definite hint to prove that humans can be introducing pathogens in these regions”, says Marta Cerdà-Cuéllar, researcher at the IRTA-CReSA. “These Salmonella and Campylobacter strains, which are a common cause for infections in humans and livestock, do not usually cause death outbreaks in wild animals. However, the emerging or invasive pathogens that arrive to highly sensitive populations -such as the Antarctic and Subantarctic fauna- could have severe consequences and cause the local collapse and extinction of some populations.”

Northen and Southern Hemisphere: migrating route for marine birds and pathogens

The study shows the risk of reverse zoonosis is higher in areas that are closer to inhabited areas, such as theFalkland Islands, and probably the Tristan da Cunha archipelago. In this situation, the biological connectivity between Antarctic and Subantarctic communities through marine birds is a factor that would speed up the circulation of zoonotic agents among the ecosystems from different latitudes.

“This could be the case, for instance, of the Subantarctic Stercorarius antarcticus: a scavenger marine bird could get the pathogen and spread it from Subantarctic latitudes to the Antarctica,” says González-Solís.

Polar areas: not all the biodiversity is protected

The Antarctic Treaty protocol on Environmental Protection sets a series of principles that can be applied to human activity in Antarctica to reduce the human footprint in the white continent. However, some Subantarctic areas -which are also the habitat of birds such as the brown skua or the giant petrel– are not protected by the protecting regulation and could become the entrance for pathogen agents in polar ecosystems.

“Our results show it is easier for humans to introduce pathogen agents in the pristine areas in the Antarctica. As a result, pathogens entering the furthest ecosystems in the Southern Hemisphere could be a serious threat for the future of wildlife. Therefore, it is essential to adopt biosecurity measures to limit the human impacts in the Antarctica,” notes Jacob González-Solís.

World’s oldest fossils discovery in Canada


This video says about itself:

2 March 2017

Remains of microorganisms at least 3,770 million years old have been discovered by an international team led by UCL scientists, providing direct evidence of one of the oldest life forms on Earth.

Tiny filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB), Quebec, Canada.

From University College London in England:

World’s oldest fossils unearthed

March 1, 2017

Remains of microorganisms at least 3,770 million years old have been discovered by an international team led by UCL scientists, providing direct evidence of one of the oldest life forms on Earth.

Tiny filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB), Quebec, Canada.

The NSB contains some of the oldest sedimentary rocks known on Earth which likely formed part of an iron-rich deep-sea hydrothermal vent system that provided a habitat for Earth’s first life forms between 3,770 and 4,300 million years ago. “Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed. This speedy appearance of life on Earth fits with other evidence of recently discovered 3,700 million year old sedimentary mounds that were shaped by microorganisms,” explained first author, PhD student Matthew Dodd (UCL Earth Sciences and the London Centre for Nanotechnology).

Published today in Nature and funded by UCL, NASA, Carnegie of Canada and the UK Engineering and Physical Sciences Research Council, the study describes the discovery and the detailed analysis of the remains undertaken by the team from UCL, the Geological Survey of Norway, US Geological Survey, The University of Western Australia, the University of Ottawa and the University of Leeds.

Prior to this discovery, the oldest microfossils reported were found in Western Australia and dated at 3,460 million years old but some scientists think they might be non-biological artefacts in the rocks. It was therefore a priority for the UCL-led team to determine whether the remains from Canada had biological origins.

The researchers systematically looked at the ways the tubes and filaments, made of haematite — a form of iron oxide or ‘rust’ — could have been made through non-biological methods such as temperature and pressure changes in the rock during burial of the sediments, but found all of the possibilities unlikely.

The haematite structures have the same characteristic branching of iron-oxidising bacteria found near other hydrothermal vents today and were found alongside graphite and minerals like apatite and carbonate which are found in biological matter including bones and teeth and are frequently associated with fossils.

They also found that the mineralised fossils are associated with spheroidal structures that usually contain fossils in younger rocks, suggesting that the haematite most likely formed when bacteria that oxidised iron for energy were fossilised in the rock.

“We found the filaments and tubes inside centimetre-sized structures called concretions or nodules, as well as other tiny spheroidal structures, called rosettes and granules, all of which we think are the products of putrefaction. They are mineralogically identical to those in younger rocks from Norway, the Great Lakes area of North America and Western Australia,” explained study lead, Dr Dominic Papineau (UCL Earth Sciences and the London Centre for Nanotechnology).

“The structures are composed of the minerals expected to form from putrefaction, and have been well documented throughout the geological record, from the beginning until today. The fact we unearthed them from one of the oldest known rock formations, suggests we’ve found direct evidence of one of Earth’s oldest life forms. This discovery helps us piece together the history of our planet and the remarkable life on it, and will help to identify traces of life elsewhere in the universe.”

Matthew Dodd concluded, “These discoveries demonstrate life developed on Earth at a time when Mars and Earth had liquid water at their surfaces, posing exciting questions for extra-terrestrial life. Therefore, we expect to find evidence for past life on Mars 4,000 million years ago, or if not, Earth may have been a special exception.”

See also here. And here.

Life on Earth may have begun as dividing droplets. Shape-shifting blobs of chemicals could split to reproduce, simulations show. By
Emily Conover, 7:00am, March 21, 2017: here.

Carnivorous plants helped by bacteria


This video from Malaysian Borneo says about itself:

9 February 2007

David Attenborough looks at another meat eating plant – the pitcher plant and how it catches insects. From the BBC.

From Science News:

Bacteria help carnivorous plants drown their prey

Microbes alter surface tension in the water traps of pitcher plants

By Susan Milius

7:05pm, November 22, 2016

Bacteria may be a meat-eating plant’s best friends thanks to their power to reduce the surface tension of water.

The carnivorous pitcher plant Darlingtonia californica releases water into the tall vases of its leaves, creating deathtraps where insect prey drown. Water in a pitcher leaf starts clear. But after about a week, thanks to bacteria, it turns “murky brown to a dark red and smells horrible,” says David Armitage of the University of Notre Dame in Indiana. Now, he’s found that those bacteria can help plants keep insects trapped. Microbial residents reduce the surface tension of water enough for ants and other small insects to slip immediately into the pool instead of perching lightly on the surface, he reports November 23 in Biology Letters.

Armitage seeded tubes of clean water with fluid from the trap pools of pitcher plants and added dead crickets to feed the microbes. After sitting for a month, the mess had about the same surface tension properties as natural pitcher plant pools. Then, he created a series of increasingly dilute samples of pool soup and dropped harvester ants into each one. He found that the ants sank immediately in all but the bacteria-free water sample.

Bacterial populations in a pitcher leaf are akin to those in a mammal gut or bovine rumen, Armitage’s preliminary analysis finds. The microbes can help digest the prey as well as catch it, he says.

3,700-million-year-old life discovery in Greenland


This video says about itself:

The world’s oldest fossil: 3.7 billion year old bumps found on ancient sea bed

31 August 2016

Conical structures known as stromatolites were found in Isua, Greenland.

They were formed by prehistoric colonies of bacteria living in a shallow sea.

It suggests life may have emerged on Earth far faster than first thought.

The finding raises hopes life may have existed on Mars.

From Nature:

Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures

Published online 31 August 2016

Biological activity is a major factor in Earth’s chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth’s evolution is when did life arise and impact hydrosphere–atmosphere–lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800–3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals1, 2 from the Isua supracrustal belt (ISB), southwest Greenland3.

Here we report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1–4-cm-high stromatolites—macroscopically layered structures produced by microbial communities. The ISB stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with cross-lamination and storm-wave generated breccias. The ISB stromatolites predate by 220 Myr the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains in the 3,480-Myr-old Dresser Formation of the Pilbara Craton, Australia4, 5. The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth’s sedimentary record. A sophistication of life by 3,700 Ma is in accord with genetic molecular clock studies placing life’s origin in the Hadean eon (>4,000 Ma)6.

See also here.

Newly discovered bacterial fossils may push back the date of the earliest direct evidence of life on Earth to 3.7 billion years ago, 220 million years older than the previous record. This is roughly four-fifths of the way back to the original formation of the planet, 4.6 billion years ago. If confirmed, this discovery would have tremendous significance for our understanding of the evolution of life in the universe: here.

Coastal waters were an oxygen oasis 2.3 billion years ago. Despite being ripe for complex life, it took another 1.5 billion years for oxygen-hungry animals to evolve: here.

The breath of oxygen that enabled the emergence of complex life kicked off around 100 million years earlier than previously thought, new dating suggests. Previous studies pegged the first appearance of relatively abundant oxygen in Earth’s atmosphere, known as the Great Oxidation Event, or GOE, at a little over 2.3 billion years ago. New dating of ancient volcanic outpourings, however, suggests that oxygen levels began a wobbly upsurge between 2.460 billion and 2.426 billion years ago, researchers report the week of February 6 in Proceedings of the National Academy of Sciences: here.

Life on Earth could be nearly four billion years old, suggests new fossil discovery. The Earth was an extremely hostile place at the time as it was still being bombarded by asteroids: here.

Tiny mounds touted as the earliest fossilized evidence of life on Earth may just be twisted rock. Found in 3.7-billion-year-old rocks in Greenland, the mounds strongly resemble cone-shaped microbial mats called stromatolites, researchers reported in 2016. But a new analysis of the shape, internal layers and chemistry of the structures suggests that the mounds weren’t shaped by microbes but by tectonic activity. The new work, led by astrobiologist Abigail Allwood of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., was published online October 17 in Nature: here.

Common ancestor of all wildlife, new research


This video says about itself:

Scientists Reveal LUCA – Common Ancestor Of All Living Things On Earth

26 July 2016

Many scientists believe that all living entities on Earth originated from an ancient organism called Luca which stands for the Last Universal Common Ancestor. Now, a team led by William F. Martin of Heinrich Heine University has released a new study which aims to “reconstruct the microbial ecology of LUCA.”

Many scientists believe that all living entities on Earth originated from an ancient organism called Luca which stands for the Last Universal Common Ancestor. The single-celled being likely lived around 4 billion years ago and is thought to have eventually spawned two distinct groups of uni-celled life–bacteria and archaea.

Now, a team led by William F. Martin of Heinrich Heine University has released a new study which aims to “reconstruct the microbial ecology of LUCA.” For the research, they tested 286,514 protein clusters and found that 355 protein families likely descended from the organism. Based on the attributes of this select group, the scientists theorize that Luca was able to withstand hot temperatures and live on hydrogen and carbon dioxide instead of oxygen; it also needed metals to be in the surrounding environment.

These combined attributes seem to indicate that this so-called universal ancestor lived in a habitat similar to a hot and gassy deep-sea vent. Despite the team’s findings, critics point out that additional information is needed to prove where life began.

From Nature Microbiology:

The physiology and habitat of the last universal common ancestor

Published online: 25 July 2016

Abstract

The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life’s origin, yet information about how and where LUCA lived is lacking.

We investigated all clusters and phylogenetic trees for 6.1 million protein coding genes from sequenced prokaryotic genomes in order to reconstruct the microbial ecology of LUCA. Among 286,514 protein clusters, we identified 355 protein families (∼0.1%) that trace to LUCA by phylogenetic criteria. Because these proteins are not universally distributed, they can shed light on LUCA’s physiology.

Their functions, properties and prosthetic groups depict LUCA as anaerobic, CO2-fixing, H2-dependent with a Wood–Ljungdahl pathway, N2-fixing and thermophilic. LUCA’s biochemistry was replete with FeS clusters and radical reaction mechanisms. Its cofactors reveal dependence upon transition metals, flavins, S-adenosyl methionine, coenzyme A, ferredoxin, molybdopterin, corrins and selenium. Its genetic code required nucleoside modifications and S-adenosyl methionine-dependent methylations. The 355 phylogenies identify clostridia and methanogens, whose modern lifestyles resemble that of LUCA, as basal among their respective domains.

LUCA inhabited a geochemically active environment rich in H2, CO2 and iron. The data support the theory of an autotrophic origin of life involving the Wood–Ljungdahl pathway in a hydrothermal setting.

See also here.

Ocean archaea more vulnerable to deep-sea viruses than bacteria. Deadly attacks boost microbes’ role in carbon, nutrient cycles. By Thomas Sumner, 4:35pm, October 12, 2016: here.

Hibernating brown bears and bacteria, new study


This video from North America is called Black Bear and Cubs Hibernate | BBC.

Another video used to say about itself:

Bears’ gut microbes help stave off ill effects of the munchies

8 February 2016

If you’ve ever dreamed of eating as much as you want with no consequences, you might envy the brown bear. Researchers have found that their gut microbiota changes drastically throughout the year, helping them avoid obesity and save energy in winter.

The bugs don’t prevent bears from getting chubby, however. Before going into winter hibernation, brown bears stuff themselves with all the food they can find, rapidly gaining body fat to last them through their long slumber – but they suffer none of the health problems that obesity normally entails as a result. An international team of scientists analyzed fecal samples from 16 wild bears to understand why the dramatic seasonal nutrition changes do not harm their health, an article published in Cell Reports says. The team found that the gut microbiotia in bears changes throughout the year.

“During winter hibernation, the concentration of several specific molecules in the bear’s blood increase, a process that we believe reflects changes in the gut microbiota. When summer is well underway, the omnivorous bear eats varied diet, which increase microbial diversity,” senior researcher Fredrik Bäckhed from the University of Gothenburg in Sweden said.

The team revealed that “summer” bacteria are believed to be responsible for weight gain, while “winter” or “hibernation” bacteria help bears to conserve energy through insulin resistance.

“Studies have shown that the brown bear is insulin sensitive during the summer, while it develops insulin resistance during the winter months, in order to reduce energy consumption in the body and save energy for the brain,” says the press release on the research.In order to understand the mechanism better the scientists tested the bearsgut bacteria on germ-free mice. The mice who received “summer” bacteria gained weight faster than those injected with “winter” bacteria.

The mice that increased their capacity to store fat due to “summer” bacteria, however, remained “metabolically healthy” without suffering from problems associated with obesity.

“Especially interesting was the notion that the mice became fatter without developing insulin resistance, similar to the bears from where the microbiota was obtained,” Bäckhed said.

The scientific team says that it is too early to talk about the practical utility of the discovery, pointing to the need for further studies.

“The study is classic basic research and more studies are needed to arrive at any practical applications. But the bear study provides new knowledge on how gut microbiota affects our metabolism, a finding that may help us to develop bacteria based treatments in the future,” Bäckhed said.

From Cell Reports:

The Gut Microbiota Modulates Energy Metabolism in the Hibernating Brown Bear Ursus arctos

February 4, 2016

Highlights

•Bear microbiota composition differs seasonally between hibernation and active phase
•Blood metabolites differ seasonally in the brown bear
•The bear gut microbiota promote energy storage during summer

Summary

Hibernation is an adaptation that helps many animals to conserve energy during food shortage in winter. Brown bears double their fat depots during summer and use these stored lipids during hibernation. Although bears seasonally become obese, they remain metabolically healthy. We analyzed the microbiota of free-ranging brown bears during their active phase and hibernation. Compared to the active phase, hibernation microbiota had reduced diversity, reduced levels of Firmicutes and Actinobacteria, and increased levels of Bacteroidetes.

Several metabolites involved in lipid metabolism, including triglycerides, cholesterol, and bile acids, were also affected by hibernation. Transplantation of the bear microbiota from summer and winter to germ-free mice transferred some of the seasonal metabolic features and demonstrated that the summer microbiota promoted adiposity without impairing glucose tolerance, suggesting that seasonal variation in the microbiota may contribute to host energy metabolism in the hibernating brown bear.

Human hunting changes brown bear reproductive strategies, so that the cubs stay with their mother longer. As a result, the females have fewer offspring, but grow older: here.

Bears that eat ‘junk food’ may hibernate less and age faster. Wildlife raiding human foods might risk faster cellular aging. By Susan Milius, March 4, 2019.