Modern distribution of saltmarsh testate amoebae: regional variability of zonation and response to environmental variables

2002 ◽  
Vol 17 (5-6) ◽  
pp. 387-409 ◽  
Author(s):  
Dan J. Charman ◽  
Helen M. Roe ◽  
W. Roland Gehrels
Keyword(s):  
Environmental Variables ◽  
Testate Amoebae ◽  
Regional Variability ◽  
Modern Distribution

Siliceous microfossils in a Holocene, High Arctic peat deposit (Nordvestø, northwestern Greenland)

1994 ◽  
Vol 72 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Kimberley M. Brown ◽  
Marianne S. V. Douglas ◽  
John P. Smol
Keyword(s):  
Environmental Variables ◽  
Testate Amoebae ◽  
High Arctic ◽  
Peat Deposit ◽  
Taxon Richness ◽  
Peat Deposits ◽  
Important Region ◽  
Geochemical Analyses ◽  
Microfossil Assemblage ◽  
Fine Tune

Siliceous microfossils (diatom valves, chrysophyte stomatocysts, and testate amoebae plates) were examined from a 2.6-m thick peat deposit from Nordvestø, northwestern Greenland (76°44′N, 73° 13′W). The moss, predominantly Aplodon wormskioldii (Hornem.) R.Br., began to accumulate approximately 6500 years ago and persisted for about 2000 years. Siliceous microfossils were generally well preserved in the peat, although taxon richness was low (i.e., only 19 diatom taxa, 16 chrysophyte cyst morphotypes, and 4 testate amoebae genera). Despite the paucity of taxa, marked shifts in species composition were recorded. Geochemical analyses and biogenic silica determination on the peat did not show any significant trends. To our knowledge, this study represents the first such combined analysis of a High Arctic peat, so our interpretations should be considered tentative. Environmental variables were not stable during the 2000 years of peat accumulation, as suggested by microfossil assemblage changes. For example, about 5000 years BP, diatoms reached their maximum relative abundance with taxa indicative of wetter habitats. We hypothesize that an influx of meltwater to the peat may have occurred at this time, perhaps because of wetter conditions or larger accumulations of snow during winter. These preliminary data indicate that siliceous microfossil analyses from arctic peat cores may eventually fine-tune paleoecological inferences for this climatically important region, once the environmental variables determining species distributions in peat deposits are determined. Key words: peat deposits, Greenland, diatoms, chrysophyte cysts, protozoan plates, paleoecology.

Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

2010 ◽  
Vol 17 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Katarzyna J. Chwedorzewska
Keyword(s):  
Environmental Variables ◽  
Climate Changes ◽  
Biological Significance ◽  
Global Changes ◽  
Factors Affecting ◽  
Low Diversity ◽  
Main Factors ◽  
The Antarctic ◽  
High Diversity ◽  
Temperature Water

ABSTRACTThe geographic position, astronomic factors (e.g. the Earth’s maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation.Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

Sustainability: Incorporating Social and Environmental Variables in the Analysis of Credit in Brazil

2012 ◽  
Author(s):  
Luiz C. J. Perera ◽  
Aida Maria M. Milani ◽  
Roberto Borges Kerr ◽  
Marco Antonio F. Milani Filho
Keyword(s):  
Environmental Variables

Testate Amoebae in the 407 Million-Year-Old Rhynie Chert

2018 ◽  
Author(s):  
Christine Strullu-Derrien ◽  
Paul Kenrick ◽  
Tomasz Goral ◽  
Andrew H. Knoll
Keyword(s):  
Testate Amoebae ◽  
Rhynie Chert

Regional Variability of Michigan Niagaran Reefs and the Impact on CO2 Storage Resources

2019 ◽  
Author(s):  
Autumn Haagsma ◽  
Andrew Burchwell ◽  
Amber Conner ◽  
Jackie Gerst ◽  
Wayne Goodman ◽  
...  
Keyword(s):  
Co2 Storage ◽  
Regional Variability ◽  
The Impact
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