#biocrust

Excerpt from this story from Smithsonian Magazine:

Under the dry, piercing heat of the Utah sun, Sasha Reed is growing plots of plants—and bacteria, lichen and fungi, too. But Reed is no farmer, and at first glance, her fields look to be mostly dirt. She’s an ecologist, and what she is growing is cryptobiotic soil.

Also called biocrust, cryptobiotic soil is a community of tiny, dirt-dwelling organisms that form a distinct crust on the top of soil in arid landscapes. These crusts are vital across Earth’s dryland ecosystems, helping to hold loose soil together and prevent erosion. They retain water, provide nooks for other microbes to live in and add nitrogen to the soil.

Cryptobiotic soil often looks like a discolored patch of ground. Upon closer inspection, the stain becomes a mosaic of small, dark lumps, dotted with tiny beds of moss and inconspicuous patches of lichen. But it can also look very similar to regular, crusty soil. Although the crunchy earth might be tempting to trek over, like stomping through a pile of crisp autumn leaves, that’s a major faux pas: Biocrust can take decades to regenerate.

And these days, in addition to getting crushed by boots, biocrusts are threatened by another kind of human footprint: climate change. So researchers are diligently working to learn more about the crusts and how to restore them.

“It’s been a pretty busy but also exciting time, because we’re kind of inventing how to do this,” says Anita Antoninka, a plant and soil ecologist at Northern Arizona University in Flagstaff who studies the crusts.

The drylands where biocrusts reside are vital ecosystems, she says, but they are some of the most degraded around the globe. As biocrusts decline in these areas, soil fertility will drop, and wind erosion will blow away the loose, unprotected dirt. Less water will soak into the ground. Even the carbon cycle could be affected, as there will be fewer tiny life forms absorbing carbon dioxide.

Biocrusts form when filimentous cyanobacteria and/or fungi knit the surface of the soil together, forming a stable aggregate. You can tell a biocrust from normal soil because it retains its shape when you pick it up and it has little dangly bits of soil (the cyanobacteria holding the soil):

There are different types of biocrusts, distinguished by the dominant organism. From right to left there are light cyanobacterial, dark cyanobacterial (the cyanobacteria are have dark sunscreen pigment), lichen, and moss/bryophite crusts.

Biocrusts form in places where plant cover is low, thus they are often found in deserts (in the pic below basically all of the rough ground cover is biocrust on gypsum soil, which they love). But they can be found in any climate (there's actually a small area in ohio where they are common).

Biocrusts are NOT formed directly on the surface of rocks (left pic), they are SOIL aggregates. They also DON'T include areas where algae have colonized the soil but where the surface cannot be removed as seperate from the rest of the soil column (this would probably be more of a biofilm (right pic)):

 So this was a barren biofilm hot spot that I kinda poked around at for a bit while enjoying KY glade cress in-situ two weekends ago. I still would like to one day get these fully ID’d  at some point but all of these are very unique and strange, constantly overlooked species due to the obscurity of them.

 Photo is biofilm soup...

Collema spp. (black jelly crust lichen group) is mixed with Nostoc spp. (not N. commune so I have no clue really what it is? Any algal biofilm experts out there wanna point me into the id directions ) 

Astrella tenella 

 I am pretty sure this may be a delicate starwort, like a real one( not one of the variants of some hemispheric liverwort) , they don’t usually grow in large colonies and most of the pictures of them that get reported are false unless they have the small form and the dried bodies. The thallus is often partially dried to the point that it looks near dead or like little dots attached to decayed segments on the ground. With that said, I talked to two of my friends that are pretty adept/mastered at identification and they said they can’t truly validate any delicate starworts without their reproductive organs present. So I still don’t know for sure but maybe someone will help on INAT eventually. The delicate starwort is rather rare, weather that be due to exposed shallow slow seeps with large karsty sheets to keep competition low being a rare thing or that they get over looked all the time due to being small as heck, it’s unclear. There are like 11 out of 15 posts on I nat that are legitimate and truly fit  *research grade*  id and the rest are misidentified or mis-verified according to my friends. So who knows, this could just be one of the other cryptid and understudied Astrella spp.

Excerpt from this story from Science Magazine:

Just as our skin is key to our well-being, the “skin” covering desert soils is essential to life in dry places. This “biocrust,” made up of fungi, lichens, mosses, blue-green algae, and other microbes, retains water and produces nutrients that other organisms can use. Now, new research shows climate change is destroying the integrity of this skin.

Such “biocrusts” cover 12% of all land on Earth, so keeping them healthy is essential for the health of the planet. As they disappear, deserts may expand, says Bettina Weber, an ecologist at the University of Graz who was not involved with the work.

Until the 1980s, few scientists paid much mind to the crunching underfoot while traipsing through grasslands, deserts, and other drylands. The crackling, it turns out, comes from centuries-old conglomerations of life that help retain what little water there is and produce life-sustaining nutrients such as nitrogen and carbon. “Biocrusts play critical roles in arid ecosystems,” says Trent Northen, a biochemist studying microbial communities at Lawrence Berkeley National Laboratory.  

Researchers had assumed anything in a biocrust could take the heat, given that they thrive where it’s dry and hot. But in 2013, scientists discovered climate change is changing the microbial composition of biocrusts. A new survey of these organisms in a pristine grassland in Canyonlands National Park in Utah has uncovered a hidden vulnerability of some of the lichens in these crusts.

Twice a year since 1996, researchers from the U.S. Geological Survey (USGS) have headed to 12 soccer field–size plots in the park’s grasslands to take stock of the kinds and amounts of lichens, mosses, fungi, and microbes—and the surrounding plants. The original goal was to monitor the spread of a nonnative plant called cheatgrass and its effects on the biocrust and other life. The researchers were able to compare their findings with results of a study in the park done in the late 1960s. “It is truly impressive that the authors have these records over such a long timespan,” Weber says.

Almost all the lichens have been waning, particularly the kinds that help convert nitrogen in the air to a form organisms can use, Finger-Higgens and her team report today in the Proceedings of the National Academy of Sciences. In 1967 and in 1996, those nitrogen-fixing lichen made up 19% of the biocrust, even though the percentage did fluctuate from year to year. Since then, that percentage has shrunk to just 5%, and it shows no sign of increasing again.

Well, setting aside how unbelievably cool they are, they have very important ecosystem functions. Biocrusts exist where there is a lack of plant cover. Plant roots help to hold soil in place and biocrusts provide that same function because cyanobacteria hold the soil particles together. When biocrusts are disturbed, the underlying soil is eroded away.

Biocrusts are also important for nutrient cycling, particularly in the deserts where nutrients are limited. Cyanobacteria, lichens, and mosses all photosynthesize so they are fixing carbon into the soil. Some cyanobacteria also fix atmospheric nitrogen, which is a super energetically costly thing to do and is very important given that nitrogen deficiency very commonly limits plant/organism growth. These nutrients are also likely being absorbed by the surrounding plant life, thus befitting the whole system.

On top of that, biocrusts host a great diversity of microorganisms. These organisms live life on the edge of habitatability. There is so much we can learn from studying how they survive and thrive under such desolate conditions. And we can use that knowledge to build a better picture of how life functions as well as steal from mother nature to improve our biotech.