Tossing dead salmon is good for plants

By Mark Kinver Environment reporter, BBC News

25 November 2018

Never mind silver bells and cockleshells, Mary should have tossed dead fish to help her garden grow.

A team of US researchers has found that sockeye salmon carcasses has helped boost tree growth by up to 20%.

Over a 20-year period, students from the University of Washington tossed dead fish from a stream on to a river bank.

Data shows the nutrients from the rotting flesh boosted growth in the area's trees.

What did the scientists do?

For two decades, students taking part in a long-term study on who/what was eating sockeye salmon in a stream in Alaska have been tossing fish carcasses on to one river bank in order to avoid double counting them during surveys.

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Centipedes and Millipedes: Lots of Legs, What's the Difference?

By Greg Uyeno, Live Science Contributor | December 4, 2018 01:20pm ET

Centipedes and millipedes belong to the subphylum of arthropods called myriapoda. In Greek, myriapoda means "countless feet." Myriapods share the basic body structure of a head and segmented body, or trunk, with many legs.

Scientists estimate that there are around 8,000 species of centipedes and 80,000 species of millipedes. "We have a wealth of diversity" within these groups, said Derek Hennen, an entomologist and doctoral student at Virginia Tech. The diversity of centipedes and millipedes may not be obvious to nonexperts, Hennen said, because many species of these arthropods are found in only a limited range.

Noticeable differences

Behavior is one of the easiest ways to tell if a many-legged critter discovered under a log or a pile of dead leaves is a centipede or a millipede. "If it runs away immediately, it will be a centipede. If it curls up and stays motionless, it will be a millipede," Hennen said.

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Marmoset study gives insights into loss of pleasure in depression

December 4, 2018, University of Cambridge

Now, in a study involving marmosets, scientists at the University of Cambridge have identified the region of the brain that contributes to this phenomenon, and shown that the experimental antidepressant ketamine acts on this region, helping explain why this drug may prove effective at treating anhedonia.

Depression is a common and debilitating condition which is recognised as a leading cause of disability worldwide. A survey published in 2016 found that 3.3 out of every 100 UK adults had experienced depression in the week before being interviewed.

A key symptom of depression is anhedonia, typically defined as the loss of ability to experience pleasure. However, anhedonia also involves a lack of motivation and lack of excitement in anticipation of events. All these aspects have proven difficult to treat. One major issue slowing down progress in developing new treatments is that the brain mechanisms that give rise to anhedonia remain largely unknown.

"Imaging studies of depressed patients have given us a clue about some of the brain regions that may be involved in anhedonia, but we still don't know which of these regions is causally responsible," says Professor Angela Roberts from the Department of Physiology, Development and Neuroscience at the University of Cambridge.

"A second important issue is that anhedonia is multi-faceted—it goes beyond a loss of pleasure and can involve a lack of anticipation and motivation, and it's possible that these different aspects may have distinct underlying causes."

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Study finds indications for recovery after ecosystem pollution

December 5, 2018, University of Konstanz

Environmental damage caused by human activity can reduce the number of plant and animal species dramatically. At the same time, very little is known about how biodiversity recovers after ecosystem pollution is curtailed and has been cleaned up. As was common in the mid-1900s, Lake Constance, one of the largest freshwater lakes in Europe, suffered from eutrophication, or nutrient contamination caused by agricultural and waste water run-off. A study by the universities in Konstanz and Glasgow has now revealed that one European whitefish species expanded its genetic variation through hybridization with other whitefish species during the period of eutrophication. The study, led by the Konstanz-based biologist Dr. Jasminca Behrmann Godel along with her colleague Dr. Kathryn R. Elmer from the University of Glasgow, was published in the journal Nature Ecology and Evolution. This genetic mixture contributed to an expansion in biodiversity once the ecosystem recovered.

The diminished water quality in Lake Constance due to eutrophication destroyed the natural habitats and led to the extinction of two of the five whitefish species that had only existed in this lake as well as to the hybridization of the three remaining species. This had an impact on commercial fisheries in the lake. In the 1980s, concerted efforts to reduce eutrophication quickly re-established Lake Constance's original state.

Biologists examined the functional phenotypical and genomic variation of the European whitefish (gangfisch: Coregonus lavaretus macrophthalamus) in order to demonstrate that its biodiversity expanded within a short period of time after the ecosystem had recovered from nutrient contamination. In less than ten generations, the European whitefish developed a wide variation in the number of gill rakers—which are used to filter plankton from the water—thus rendering it able to occupy a broader ecological niche than before eutrophication. This is one of the fastest evolutionary rates ever recorded in the animal kingdom.

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Axolotls in crisis: the fight to save the 'water monster' of Mexico City

The city’s floating gardens are a prime party spot – but pollution has driven the axolotl population to the verge of extinction. Can a radical plan save them?

Alan Grabinsky in Mexico City

Tue 4 Dec 2018 11.00 GMTLast modified on Tue 4 Dec 2018 11.12 GMT

Like many residents of Mexico City, my experience of the floating gardens of Xochimilco has mostly been tinged with alcohol. After all, every weekend, this Unesco world heritage site turns into a bacchanal, with groups aboard the canals’ iconic boats celebrating everything from high school graduations to engagements and weddings.

But this is a weekday morning, and Carlos Sumano, who is steering my canoe through the floating gardens, or chinampas, says that sort of unfettered use has taken its toll on the ecosystem. During his six years working in Xochimilco, Sumano has come across everything from pushchairs to television sets in canals. 

The loss of the axolotl is traumatic for Mexico City: the creature is vital both to its ecosystem and its imagination

Water pollution has also affected the region’s most unique creature: the axolotl.

When the Aztecs established themselves in the nearby city of Tenochtitlan, they found in Xochimilco what appeared to be the larva of a salamander. Fascinated, they called the animal “water monster” and incorporated it into their mythology as the mischievous and renegade brother of the god Quetzalcoatl.

Its divine character didn’t keep the Aztecs from eating it but, thanks in large part to the low-impact agriculture of Xochimilco, human and amphibian thrived.

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