Päiväkirja-arkisto kohteelle maaliskuu 2020

maaliskuu 1, 2020

January Salt Spring Island Fungus of the Month: Exidiopsis effusa

January's fungus of the month is Exidiopsis effusa, an unremarkable white crust fungus visible as a lumpy crust on dead, barkless wood. However, when conditions are just right, the crust grows ice wool: long silky hairlike icicles.

observation by vail

Individual ice "hairs" remain completely separate and don't freeze together where they touch, but nearby hairs follow similar paths and make smooth curls and waves together.

Ice wool has been observed between 45 and 55 degrees north in France, Germany, Wales, Scotland, Switzerland, Ireland, and Canada (including Salt Spring Island). It forms in calm, windless conditions when the air is humid and the temperature is just below zero. If the temperature changes or the air gets dryer, the ice wool disappears.

Its formation was thought to be fungi-related, but the details were a mystery until 2015, when a German research group led by Dr. Diana Hofmann collected samples of wood that had grown ice wool over the winters of 2010-2014. Genetic analysis of the samples found that while most rotting wood supports several species of fungi, Exidiopsis effusa was present in every sample, and there were a few samples where it was the only fungus present.

They also collected and melted the ice itself, and found that it contained dissolved fulvic acids, a result from fungal digestion of wood, which may help explain the weird behaviour of the ice.

Exidiopsis effusa isn't the only living thing that grows fleeting, strange ice. Frostweed, Verbesina virginica, grows at forest edges across the South-Eastern United States. During the first freeze of winter, the frostweed stem ruptures and water oozes slowly out of long vertical cracks, forming thin ribbons of ice.

observation by jollyphoto

Julkaistu maaliskuu 1, 2020 01:21 AP. käyttäjältä corvi corvi | 2 kommenttia | Jätä kommentti

maaliskuu 5, 2020

Vote for Canada's National Lichen!

The Canadian Museum of Nature has set up a vote to select Canada's National Lichen! There are seven candidates. Read about the candidates and vote for your favourite here!

Julkaistu maaliskuu 5, 2020 04:47 AP. käyttäjältä corvi corvi | 0 kommenttia | Jätä kommentti