Stromatolites are mounds of cyanobacteria and sediment that have been found in the fossil record since 3.5 billion years ago in the Archean time period. The mounds resemble a cross between a cauliflower and a rock:
Living stromatolites were not discovered until 1956 in Shark Bay off the west coast of Australia (There's some poetry to accompany this stromatolite tour). These present-day algal mounds are also found in the Bahamas.
"Stromatolite" is derived from stroma, Latin for layer, and it is easy to see why. The laminae are particularly well-defined, especially in thin section.
Shark Bay is the site of discovery of
chlorophyll f, a type form of chlorophyll that absorbs further in the infrared light part of the spectrum (red) than other chlorophylls. (Are you blue-green with envy?)
Chlorophyll f's discovery was made by scientists at the University of Sydney led by Dr. Min Chen. It is the first discovery of a new form of chlorophyll since about the time stromatolites were discovered in Shark Bay.
Pop Quiz:
1) Where are these stromatolites? (They are poetically called "Petrified Sea Gardens.")
2) Based on today's post, what are these organic structures called?
3) Where are these stromatolites? Hint: maple syrup is big here.
4) Let out your inner POETS for PEOTS: Write your best stromatolite haiku, limerick, or any other poetry form. Help celebrate two years of scientists who like to write and writers who like science. . .
Peeling those (not-always round) onion layers,
Steph
The cryptobiotic soil crusts of Arches National Park, Utah, are the inspiration for this week's post.
Cryptobiotic soil crusts are communities of living organisms on the soil surface in arid and semi-arid ecosystems. They are found worldwide.
Cryptobiotic soil crusts perform important ecological roles including carbon fixation, nitrogen fixation, soil stabilization, altering soil albedo and affecting germination and nutrient levels in vascular plants.
The "crypto" part of the name refers to the hidden nature of the crusts. The crusts form very slowly and can look like surrounding soil in the first few decades. A footprint on these soils can cause damage that may take 250 years to recover in low rainfall areas like Arches' Fiery Furnace.
A Scanning Electron Microscope (SEM) image of this crust reveals a complex array of cyanobacteria (the bacteria formerly known as blue-green algae), lichen (see our 100th post on litmus and lichen), and mosses.
This one-minute video shows the effect water has on part of the mosses in the cryptobiotic soil crust.
Yes, a very delicate organism surrounds much of Delicate Arch in Arches N.P. and all over Utah. Treading lightly on marked trails will preserve these important, complex cryptobiotic soil crusts.
Have you encountered cryptobiotic soil crust at Arches or elsewhere? May you have photos but no footprints to share. . .
I am also curious about whether reddish-orange landscapes are more appealing to each of you than the green and blue ones. I grew up in the greener landscapes of New England (NE!) but I have learned to love the red-oranges after living in the west for more than half my life. The blue-greens are beautiful, too, of course.
Crustily and cryptically,
Steph
Arches: Delicate Arch and La Sal Mountains
Bryce: Peakaboo Trail
Zion: Near Angel's Landing Trail
