This scientific Nature never ceases to amaze us. When we understand why something happens through science, the wonder gets enhanced. I have already done four parts of scientific explanations of amazing things happening in nature. This is the fifth part. Hope you like this series. 

Glowing Dolphins: Bioluminescence brought by dinoflagellates

A pod of glowing dolphins has been observed recently. They were electric blue, trailing swaths of light as they rode the bow wave. Watch this video that captured the magic of science so wonderfully ....

It was a stunning example of "bioluminescence". The phenomenon is the result of a chemical reaction in billions of single-celled organisms called dinoflagellates congregating at the sea surface. These organisms are a type of phytoplankton – tiny microscopic organisms many sea creatures eat.

Dinoflagellates switch on their bioluminescence as a warning signal to predators, but it can also be triggered when they're disturbed in the water—in this case, by the dolphins.

Bioluminescence usually serves as a communication function, such as to warn off predators, attract a mate or lure prey. For many species, light pollution in the ocean may compromise this biological communication strategy.

And for light-producing organisms such as dinoflagellates, excess artificial light may reduce the effectiveness of their bioluminescence because they won't shine as bright, potentially increasing their risk of being eaten.

----

7 Most Wonderful Natural Phenomena In The World and their scientific explanations

--

Strange natural things that science explains - or in the process of understanding - why they exist at all ...

-------

How 'ice needles' weave patterns of stones in frozen landscapes

Patterns woven by ice needles : Circles of stones in Svalbard, Norway. Each circle measures roughly 10 feet, or 3 meters, across. New research provides insight into how these features form in rocky, frost-prone landscapes. Credit: Bernard Hallet/University of Washington

Nature is full of repeating patterns that are part of the beauty of our world. An international team, including a researcher from the University of Washington, used modern tools to explain repeating patterns of stones that form in cold landscapes.

The new study, published Oct. 5 in the Proceedings of the National Academy of Sciences, uses experimental tools to show how needles of ice growing randomly on frozen ground can gradually move rocks into regular, repeating patterns. The team, based mainly in China and Japan, uses a combination of novel experiments and computer modeling to describe these striking features with new theoretical insights.

The presence of these amazing patterns that develop without any intervention from humans is pretty striking in nature.

One of the reasons for the patterns is needle ice. As the temperature drops, the moisture contained in the soil grows into spikes of ice crystals that protrude from the ground.

When you go out in the backyard after a freezing night and you feel a little crunch under the foot, you're probably walking on needle ice.

As needle ice forms it tends to push up soil particles, and if there are any, small stones. More needle ice can form on patches of bare soil compared to rock-covered areas. The ice needles will slightly displace any remaining stones in the barer region. Over years, the stones begin to cluster in groups, leaving the bare patches essentially stone-free.

That kind of selective growth involves interesting feedbacks between the size of the stones, the moisture in the soil and the growth of the ice needles.

Watch a video that shows how this happens here:

Anyuan Li et al, Ice needles weave patterns of stones in freezing landscapes, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2110670118

-----

What causes Australia's 'Fairy Circles'?

Fairy circles—barren patches which make polka-dot patterns in dry and desert areas—were first described by scientists in Namibia in the 1970s, sparking global debate about the phenomenon.

Aboriginal people told the researchers that these regular circular patterns of bare 'pavements' are occupied by spinifex termites.

The team surveyed plots containing multiple "fairy circles" on Nyiyaparli country, east of Newman in WA's East Pilbara region, excavating 60 trenches down to 15cm in depth. They also looked at pavements on Newhaven, an Australian Wildlife Conservancy property in Warlpiri country, Northern Territory.

"The pavement surface is concrete hard," according to the researchers. "After they dug and then dusted to clean the trenches, 100% of them had termite chambers seen horizontally and vertically in the matrix. Forty-one percent of the trenches contained live harvester termites.

Termites and termite structures were much more common under the pavements than in the spinifex grasslands next to them which provided alternative scientific evidence to the dominant international theory explaining the 'fairy circle' phenomenon in Australia.

 Fiona Walsh et al, First Peoples' knowledge leads scientists to reveal 'fairy circles' and termite linyji are linked in Australia, Nature Ecology & Evolution (2023). DOI: 10.1038/s41559-023-01994-1

----

Iron Water
In the last few years, scientists have recorded rivers and streams in pristine regions of Alaska that are as acidic as vinegar and have levels of electrical conductivity, an indicator of dissolved metals or minerals, similar to industrial wastewater. Plus, the waterways are turning orange. Scientists agree that climate change is behind the changes, but aren’t yet sure precisely how. The first possible explanation is that thawing permafrost allows bacteria to reduce iron, which is soluble in water. Once in the water, that reduced iron can be oxidized, turning bright orange. The second possibility is that the permafrost thaw lets iron leach out of the bedrock for the first time in thousands of years. The metal gets oxidized in streams and rivers, turning the water orange.

Why this matters: Iron in the water suffocates the invertebrates that fish feed on. And iron and other metals hinder fish respiration. Salmon, in particular, are keystone species in the rivers of Alaska, and their health directly impacts many of the other living organisms in the ecosystem they occupy. Native Alaskans also depend on the rivers for fish and drinking water.
What the experts say: “It's fascinating from a scientific point of view, but from an emotional point of view, it's sad,” says U.S.G.S biologist Mike Carey of the changes he's witnessing. “The alarming thing is how far our human reach is, in a big way.”

Tukpahlearik Creek in northwestern Alaska's Brooks Range runs bright orange where permafrost is thawing. Credit: Taylor Roades