OBJECTIVE: To analyze anomalies of a biomineralized exoskeleton of a trilobite. MATERIALS: A specimen of Dalmanitina socialis from the Upper Ordovician Letná Formation at Veselá near Beroun, Czechoslovakia, curated at the Czech Geological Survey in Prague. METHODS: The internal mold and external mold and latex casts were coated with ammonium chloride sublimate and photographed. RESULTS: A substantial reduction of the eye surface associated with changes in morphology and surface structure was noted. CONCLUSIONS: The anomaly is believed to be the result of a healed injury after an unsuccessful predatory attack. Based on the presumed mechanism of injury, a 'large arthropod' is proposed to be the potential attacker. SIGNIFICANCE: The low incidence of sublethal attack to cephala in collections of Cambrian to Carboniferous trilobites implies that most such attacks were fatal, rendering this specimen unique and capable of providing insight into healing processes. LIMITATIONS: Post-mortem damage rendered analysis difficult. SUGGESTIONSFOR FURTHER RESEARCH: Exploration of other cases of healed trauma in order to understand Ordovician ecosystems.
- MeSH
- členovci * MeSH
- ekosystém MeSH
- pitva MeSH
- regenerace MeSH
- zkameněliny * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We investigated fungal growth and community composition in buried meshbags, amended with apatite, biotite or hornblende, in Norway spruce (Picea abies) forests of varying nutrient status. Norway spruce needles and soil collected from forests overlying serpentinite had low levels of potassium and phosphorus, those from granite had low levels of magnesium, whereas those from amphibolite had comparably high levels of these nutrients. We assayed the fungal colonization of meshbags by measuring ergosterol content and fungal community with 454 sequencing of the internal transcribed spacer region. In addition, we measured fine root density. Fungal biomass was increased by apatite amendment across all plots and particularly on the K- and P-deficient serpentinite plots, whereas hornblende and biotite had no effect on fungal biomass on any plots. Fungal community (total fungal and ectomycorrhizal) composition was affected strongly by sampling location and soil depth, whereas mineral amendments had no effect on community composition. Fine root biomass was significantly correlated with fungal biomass. Ectomycorrhizal communities may respond to increased host-tree phosphorus demand by increased colonization of phosphorus-containing minerals, but this does not appear to translate to a shift in ectomycorrhizal community composition. This growth response to nutrient demand does not appear to exist for potassium or magnesium limitation.
- MeSH
- biomasa MeSH
- draslík farmakologie MeSH
- ergosterol metabolismus MeSH
- fosfor farmakologie MeSH
- hořčík farmakologie MeSH
- houby účinky léků růst a vývoj MeSH
- lesy * MeSH
- listy rostlin chemie účinky léků MeSH
- minerály metabolismus MeSH
- multivariační analýza MeSH
- půdní mikrobiologie * MeSH
- smrk účinky léků fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The WHAM-FTOX model quantifies the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (FTOX), a linear combination of the products of organism-bound cation and a toxic potency coefficient for each cation. We describe the application of the model to predict an observable ecological field variable, species richness of pelagic lake crustacean zooplankton, studied with respect to either acidification or the impacts of metals from smelters. The fitted results give toxic potencies increasing in the order H(+) < Al < Cu < Zn < Ni. In general, observed species richness is lower than predicted, but in some instances agreement is close, and is rarely higher than predictions. The model predicts recovery in agreement with observations for three regions, namely Sudbury (Canada), Bohemian Forest (Czech Republic) and a subset of lakes across Norway, but fails to predict observed recovery from acidification in Adirondack lakes (USA).
- MeSH
- chemické látky znečišťující vodu toxicita MeSH
- chemické modely * MeSH
- jezera chemie MeSH
- korýši klasifikace účinky léků růst a vývoj MeSH
- kovy toxicita MeSH
- monitorování životního prostředí metody MeSH
- protony MeSH
- zooplankton klasifikace účinky léků růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Česká republika MeSH
- Kanada MeSH
- Norsko MeSH
