Fourteen degrees of latitude and a continent apart: comparison of lichen activity over two years at continental and maritime Antarctic sites

There are marked declines in precipitation, mean temperatures and the number of lichen species with increasing latitude in Antarctica. However, it is not known which factors are the predominant controllers of biodiversity changes. Results are presented from over two years of almost continuous monitoring of both microclimate and activity in lichens at Livingston Island, South Shetland Islands, 62°S, and Botany Bay, Ross Sea region, 77°S. Lichen activity was evident over a much longer period at Livingston Island, (3694 versus 897 hours) and could occur in any month whereas it was almost completely confined to the period November–February at Botany Bay. Mean air temperatures were much lower at Botany Bay (-18° compared to -1.5°C at Livingston Island), but the temperatures at which the lichens were active were almost identical at around 2°C at both sites. When the lichens were active incident light at Botany Bay was very much higher. The differences are related to the availability of meltwater which only occurs at times of high light and warm temperatures at Botany Bay. Temperature as a direct effect does not seem to explain the differences in biodiversity between the sites, but an indirect effect through active hours is much more probable. In addition there are negative effects of stresses such as high light and extreme winter cold at Botany Bay

The Cross-Border Freedom of Form Principle Under Reservation: The Role of Articles 12 and 96 CISG in Theory and Practice

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Contract validity and the CISG

The article discusses the standards that determine the validity of contracts that are governed by the United Nations Convention on Contracts for the International Sale of Goods of 1980 (CISG). While Article 4(a) of the—CISG � the so-called ‘validity exception’—generally excludes the validity of the contract from the Convention's material scope, it does so incompletely by adding a ‘except as otherwise expressly provided in this Convention’ caveat. Against this background, the article sets out to develop a novel validity definition. According to this definition, provisions concerned with the ‘validity of the contract’ in the sense of Article 4(a) of the CISG are legal limits to party autonomy. The article continues by applying this definition to various potential validity issues as discussed in case law and legal writings. In doing so, it distinguishes between validity issues clearly not covered by the CISG (as legal limits on what to sell, legal limits on who to sell to or to purchase from, and legal limits on how to sell) and validity issues clearly covered by the CISG, as the formal validity of contracts, the validity of open-price contracts and the effect of an initial objective impossibility of the agreed performance on the contract. Finally, the article discusses a more complicated group of borderline issues that may or may not be governed by the Sales Convention, as mistakes or misrepresentations by a contracting party, the effect of contract clauses limiting a party's rights under the contract, surprising contract clauses and the effect of legal prohibitions of interest

The moss Bryum argenteum var. muticum Brid. is well adapted to cope with high light in continental Antarctica

The net photosynthetic rate (NP), chlorophyll fluorescence, carotenoid content and chlorophyll content of the cosmopolitan moss Bryum argenteum were measured in the field at Botany Bay, southern Victoria Land, continental Antarctica (77°S). Comparisons were made between sun- and shade-adapted forms, and changes were followed as the moss emerged from under the snow and during exposure of shade and sun forms to ambient light. Shade forms had lower light compensation and saturation values for NP but little difference in maximal NP rates. Shade forms exposed to ambient light changed rapidly (within five days) towards the performance of the sun forms. Surprisingly, this change was not by acclimation of shoots but by the production of new shoots. Chlorophyll and carotenoid levels measured on a molar chlorophyll basis showed no difference between sun and shade forms and also little change during emergence. The constant molar relationship between carotenoids and chlorophyll plus the high levels of the xanthophyll cycle pigments suggest that protection of the chlorophyll antenna was constitutive. This is an adaptation to the very high light levels that occur when the plants are active in continental Antarctica and contrasts to the situation in more temperate areas where high light is normally avoided by desiccation