Abstract
Subfossils of the lichens Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm. were discovered after they were exposed by ice melt in Greenland. Extracellular phenolic substances of emerging lichens were analyzed by high performance liquid chromatography and compared with those found in lichens of the same species that escaped glaciation. All major and minor phenolics of living lichens were present in subfossils, although significantly lower amounts of the major constituent, gyrophoric acid, were documented. After being subjected to experimental pressure treatments in a hydraulic press, Umbilicaria mammulata (Ach.) Tuck, thalli showed highly significant reductions in the levels of both gyrophoric acid and lecanoric acid, and the decrease was more pronounced under the more severe of two pressure treatments. The decrease in mean phenolic content following immersion in water for 5 days was not statistically significant. There was a considerable range of phenolic concentrations among thalli of modern arctic specimens of Umbilicaria as well as among thalli recently released from ice, and the variance in subfossils was not significantly different from that in living populations. Key words: tridepsides, subfossils, Umbilicaria, pressure, glaciers, high performance liquid chromatography.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 7
Claim · model-written summary
All major and minor phenolics of living lichens were present in subfossils.
- Taxon
- Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm.
Umbilicaria hyperborea
Umbilicaria krascheninnikoviie1 - Outcome
- All major and minor phenolics of living lichens were present in subfossilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All major and minor phenolics of living lichens were present in subfossils”
e1“Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm.”
Claim · model-written summary
Subfossils had significantly lower gyrophoric acid amounts.
- Taxon
- Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm.Umbilicaria hyperboreaUmbilicaria krascheninnikoviie1
- Outcome
- amounts of the major constituent, gyrophoric acide0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly lower amounts of the major constituent, gyrophoric acid, were documented”
e1“Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm.”
Claim · model-written summary
Pressure treatment significantly reduced gyrophoric acid in Umbilicaria mammulata.
- Taxon
- Umbilicaria mammulata (Ach.) Tuck
Umbilicaria mammulatae0 - Treatment
- experimental pressure treatmentse0
- Outcome
- levels of both gyrophoric acid and lecanoric acide0
- Direction
- reductionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After being subjected to experimental pressure treatments in a hydraulic press, Umbilicaria mammulata (Ach.) Tuck, thalli showed highly significant reductions in the levels of both gyrophoric acid and lecanoric acid”
Claim · model-written summary
More severe pressure caused a more pronounced decline in phenolics.
- Taxon
- Umbilicaria mammulata (Ach.) TuckUmbilicaria mammulatae1
- Treatment
- more severe of two pressure treatmentse0
- Outcome
- decreasee0
- Direction
- more pronouncede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the decrease was more pronounced under the more severe of two pressure treatments”
e1“Umbilicaria mammulata (Ach.) Tuck”
Claim · model-written summary
Five days of water immersion caused a nonsignificant decrease in mean phenolics.
- Taxon
- Umbilicaria mammulata (Ach.) TuckUmbilicaria mammulatae1
- Treatment
- immersion in water for 5 dayse0
- Outcome
- mean phenolic contente0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in mean phenolic content following immersion in water for 5 days was not statistically significant”
e1“Umbilicaria mammulata (Ach.) Tuck”
Claim · model-written summary
Phenolic concentration varied considerably among modern and ice-released thalli.
- Taxon
- Umbilicaria
.jpg?width=60)
Umbilicariae0 - Outcome
- considerable range of phenolic concentrationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“There was a considerable range of phenolic concentrations among thalli of modern arctic specimens of Umbilicaria as well as among thalli recently released from ice”
Claim · model-written summary
Subfossil variance in phenolics did not differ significantly from living populations.
- Taxon
- UmbilicariaUmbilicariae1
- Outcome
- variance in subfossilse0
- Direction
- not significantly differente0
- Comparator
- living populationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the variance in subfossils was not significantly different from that in living populations”
e1“specimens of Umbilicaria as well as among thalli recently released from ice”