Plant species, biomass and environmental characteristics of relevés along the North America Arctic bioclimate gradient

Question: How do interactions between the physical environment and biotic properties of vegetation influence the formation of small patterned-ground features along the Arctic bioclimate gradient? Location: At 68° to 78°N: six locations along the Dalton Highway in arctic Alaska and three in Canada (Banks Island, Prince Patrick Island and Ellef Ringnes Island). Methods: We analysed floristic and structural vegetation, biomass and abiotic data (soil chemical and physical parameters, the n-factor [a soil thermal index] and spectral information [NDVI, LAI]) on 147 microhabitat releves of zonalpatterned-ground features. Using mapping, table analysis (JUICE) and ordination techniques (NMDS). Results: Table analysis using JUICE and the phi-coefficient to identify diagnostic species revealed clear groups of diagnostic plant taxa in four of the five zonal vegetation complexes. Plant communities and zonal complexes were generally well separated in the NMDS ordination. The Alaska and Canada communities were spatially separated in the ordination because of different glacial histories and location in separate floristic provinces, but there was no single controlling environmental gradient. Vegetation structure, particularly that of bryophytes and total biomass, strongly affected thermal properties of the soils. Patterned-ground complexes with the largest thermal differential between the patterned-ground features and the surrounding vegetation exhibited the clearest patterned-ground morphologies.

Grain size and description on gravity core samples from ANT-IV/2 expedition to the Bransfield Strait

From the above and the grafical results it can be concluded that cores in the research area are locally dominated by turbiditic sequences, which can be observed by a strong increase in coarser sediment (>35 µm). These coarser intercalations are lacking in the vicinity of basaltic seamounts, probably due to a shadowing effect of the seamounts. The infill of the King George Basin might be dominated by a north eastern current. Sedimentary structures as observed in the cores are often lacking or vague due to hydrothermal effects (Suess, L, 1986).

Fluor and opal in surface sediment from the Bransfield Strait (Table 1)

The influence of biogenic opal sediment input (mainly diatom skeletons) on the fluorine budget of marine sediments will be shown for 24 sampling stations of the antarctic regions of Bransfield Strait, Powell Basin, South Orkney Plateau and northwestern Weddell Sea. 4 bulk samples, one from each sedimentation area, contain 9 to 28 wt.-% of biogenic opal , the clay fraction of the 24 samples investigated have 2 to 82 wt.-%. The fluorine concentration in the amorphous biogenic component is 15 ppm. 300 to 800 ppm of fluorine were measured in the clay fractions, 330 to 920 ppm in their lithogenic components. Biogenic opal causes a decrease in fluorine concentration of the sediment by a considerable amount: 6 to 56 % relative to the clay fraction, due to the proportions involved. Biogenic opal is therefore taken into account as a 'diluting' factor for the fluorine budget in marine sediments.

Ensemble prediction distribution maps of macroalgae for current conditions and four climate change scenarios and high resultion bathymetry for Potter Cove, WAP, Antarctica

Species distribution models (SDM) predict species occurrence based on statistical relationships with environmental conditions. The R-package biomod2 which includes 10 different SDM techniques and 10 different evaluation methods was used in this study. Macroalgae are the main biomass producers in Potter Cove, King George Island (Isla 25 de Mayo), Antarctica, and they are sensitive to climate change factors such as suspended particulate matter (SPM). Macroalgae presence and absence data were used to test SDMs suitability and, simultaneously, to assess the environmental response of macroalgae as well as to model four scenarios of distribution shifts by varying SPM conditions due to climate change. According to the averaged evaluation scores of Relative Operating Characteristics (ROC) and True scale statistics (TSS) by models, those methods based on a multitude of decision trees such as Random Forest and Classification Tree Analysis, reached the highest predictive power followed by generalized boosted models (GBM) and maximum-entropy approaches (Maxent). The final ensemble model used 135 of 200 calculated models (TSS > 0.7) and identified hard substrate and SPM as the most influencing parameters followed by distance to glacier, total organic carbon (TOC), bathymetry and slope. The climate change scenarios show an invasive reaction of the macroalgae in case of less SPM and a retreat of the macroalgae in case of higher assumed SPM values.

Conversations on the currency /

Mode of access: Internet.

Agreement between the United Kingdom and the United States of America for the settlement of various pecuniary claims outstanding between the two governments, together with the first schedule of claims and terms of submission thereof; also rules of procedure exchanged between the agents, 11th July, 1912.

Agreement signed at Washington, Aug. 18, 1910, by James Bryce and Philander C. Knox.

Shakspere quarto facsimiles /

--v. 25 Romeo and Juliet; the 1st quarto, 1597.--v. 26 Romeo and Juliet; the 2nd quarto, 1599.--v. 27 King Henry V; the 1st quarto, 1600.--v. 28 King Henry V; the 3rd quarto, 1608.--v. 29 Titus Andronicus; the 1st quarto, 1600.--v. 30 Sonnets; the 1st quarto, 1609.--v. 31 Othello; the 1st quarto, 1622.--v. 32 Othello, the 2nd quarto, 1630.--v. 33 King Lear; the 1st quarto, 1608.--v. 34 King Lear; the 2nd quarto, 1608.--v. 35 Lucrece; the 1st quarto, 1594.--v. 36 Romeo and Juliet; the undated quarto.--v. 37 First part of the Contention; the 1st quarto, 1594.--v. 38 True tragedy; the 1st quarto, 1595.--v. 39 Famous victories of Henry the fifth; the earliest known quarto, 1598.--v. 40-41 The troublesome raigne of John, king of England; the 1st quarto, 1591.--v. 42 Richard the third; the 3rd quarto 1602.--v. 43 Richard the third; the 6th quarto, 1622.

The century Shakespeare.

T.p. in green and black; illustrated lining papers.