Geographical Aspects of Biological Productivity

Annual plant production and total plant mass are calculated for 106 types of soil and plant formations of the world, grouped in turn by major thermal belts and bioclimatic regions (humid, semiarid, arid) within these thermal belts. Aggregate magnitudes of annual growth and total plant mass by thermal belts and their bioclimatic regions follow a sequence of alternating high values in humid regions and low values in arid regions that bears a similarity to the periodic law of geographical zonality. Maximum plant production is associated with the Tropical belt, where combinations of heat and moisture favor maximum intensity of the physical-geographic process. A related paper, by Bazilevich and Rodin, appeared in Soviet Geography, January 1971.     

Placers of the Urals,Their Formation,Distribution and Elements of Geomorphic Prediction

The gold, platinum and titanium placers are analyzed from the geomorphic point of view to establish future prospects as the Quaternary placers now being worked become depleted. The key to placer prospecting is seen in the historical sequence of deposition and redeposition in which older placers in turn became source areas for younger placers. The main metallogenetic epoch is associated with the Middle and Late Jurassic as well as a substantial part of the Cretaceous when intensive weathering of the regolith yielded rich placer accumulations in Mesozoic erosional-structural depressions that represent segments of the drainage net of the period. These depressions subsequently were the source areas for new placers as the drainage pattern was reoriented. In some areas crustal movements played a role as renewed erosion induced by uplifting resulted in the redeposition of metal in new placers. As the Quaternary placers become depleted, an effort is therefore recommended to focus prospecting and exploration in the source areas associated with the Mesozoic depressions.     

The Landscape Levels of Continents and Geographical Zonality

The traditional two-dimensional concept of latitudinal natural geographical zones is challenged on the ground that it ignores the altitude factor and differences in the character of the surface environment. An alternative three-dimensional model of zonal systems is proposed, in which so-called landscape levels corresponding to particular geomorphic levels are distinguished in terms of radiation balance and elevation. The zonal systems are combined into four worldwide groupings: (1) an inner terrestrial group corresponding to a rocky surface environment; (2) an outer terrestrial group corresponding to a cryogenic rocky environment; (3) an outer ice group, corresponding to ice-covered segments of the earth's surface, and (4) an oceanic group. The paper is devoted to the first three continental groups of zonal systems. The traditional zonality is found to be well expressed in the inner terrestrial group, but the outer groups reflect mainly Markov's law of polar asymmetry (see Soviet Geography, February 1964).     

NATURAL CAUSE-AND-EFFECT RELATIONSHIPS AND THE PREDICTION OF ENDEMIC GOITER

The incidence of endemic goiter in southeast Kazakhstan, a highly goitrogenic province of the Soviet Union, is related to the geochemical setting of the region's natural areal complexes. The occurrence of endemic goiter is usually attributed simply to iodine deficiency. However other chemical elements also tend to reduce or enhance the goitrogenic properties of a particular environment. A detailed analysis of the various environments in southeast Kazakhstan shows that not all parts of the region are equally goitrogenic and that high, medium and low risk areas may be distinguished. The various natural areal complexes of different levels of goitrogenicity are mapped together with actually observed incidence of the disease. It is recommended that public health activities, such as the provision of iodized salt, be directed in particular at the high and medium risk areas.     

CHANGES IN THE STRUCTURE OF EVAPORATION IN THE ARAL SEA BASIN

An analysis of evaporation changes in the Central Asian plain in connection with the drop of the Aral Sea level beginning in 1961 shows that there has been a reduction in evaporation from stream valleys and deltas and an increase in evaporation from irrigated land and newly formed evaporating surfaces. These new entities are primarily the Arnasay depression (west of the Golodnaya Steppe irrigation district) and the Sarykamysh depression (west of the lower reaches of the Amudarya), which have become filled with spent irrigation water draining from the irrigated land. Another new source of evaporation associated with human activity are the lakes and wetlands formed along the Kara Kum Canal as a result of the filtration of canal water. It turns out, furthermore, that irrigation on sloping piedomon plains, such as those watered by the Kara Kum Canal, requires more water than in old irrigated alluvial plains because of the additional water needed to flush salt out of the soil and to fill subsoil cavities and raise the watertable.     

COMMUTING AS AN ELEMENT OF LOCAL POPULATION MOBILITY

Commuting is defined as journeys to work or study that cross the administrative boundaries of minor civil divisions. This poses problems in the statistical analysis of some metropolitan areas, such as Baku, where large suburban territories are administratively under the jurisdiction of the central city government. Time series on commuting exist for trips from rural to urban areas, and help distinguish oblasts and major economic regions of varying levels of rural population mobility. This mobility is highest around large cities that exert a strong pull (Moscow, Leningrad, Kiev, Minsk, Khar'kov, L'vov). Rural population mobility is low in Siberia and Kazakhstan, which have a sparse network of industrial centers and low rural population density, and in Central Asia, where the indigenous population is distinguished by low social mobility. Census data for commuting in 1970 yield a typology of cities in terms of the character of commuting. Commuting distances and means of transportation are analyzed for different city size classes.     

N.I. VAVILOV,GEOGRAPHER AND EXPLORER

Academician N.I. Vavilov had an international reputation as a scientist, agronomist, botanist, geneticist, plant breeder, explorer for wild progenitors of cultivated plants, selector of new crop varieties, organizer of expeditions, administrator of a large research institute, and a statesman. Beginning in 1916 in collection of crop varieties in Iran and the Pamirs, he personally explored large segments of the earth. In 1926 he published his famous study on centers of origin of cultivated plants. While head of the Institute of Applied Botany and New Crops, he organized many expeditions to search for new varieties of crops and their wild ancestors and established an international collection of seeds. While President of the Geographical Society (1931-1940) he arranged to have the society transferred from the People's Commissariat of Education of the RSFSR to the Academy of Sciences of the USSR, thus transforming it from the Russian to the All-Union Geographical Society. He presented many lectures to the Society and greatly expanded its program of public lectures. But while on a scientific expedition to the western Ukraine, he was arrested on August 6, 1940. “An unforgiveable crime was committed. There has hardly been a more tragic fate since Galilee: the man who sought to give bread to the people died of starvation… He was a hero who gave his life for his scientific beliefs” (translated by H. L. Haslett, Birmingham, United Kingdom).     

The long-ranging macroalga Grypania spiralis from the Ediacaran Doushantuo Formation,Guizhou, South China

Wang, Y., Wang, Y. & Du, W., February 2016. The long-ranging macroalga Grypania spiralis from the Ediacaran Doushantuo Formation, Guizhou, South China. Alcheringa 40, xxx–xxx. ISSN 0311-5518

Grypania spiralis (Walcott) Walter et al., a macroalga previously reported in pre-Ediacaran successions, has been collected, together with abundant macrofossils (i.e., the Wenghui biota), from black shales of the upper Doushantuo Formation (ca 593 to 551 Ma) in northeastern Guizhou, South China. Morphologically, G. spiralis represents a carbonaceous ribbon with a continuum of forms from coiled to nearly straight. Its helicoid main body might have been suspended in the water column for photosynthesis with one end anchored or nestled into soft sediments. Grypania possessed morphological stability, and its habit endowed great competitiveness for sunlight. Remarkably, it did not change significantly in size or morphology over more than 1200 Myrs.

Ye Wang [gboywangye@126.com], School of Earth Sciences and Resources, PR China University of Geosciences, Beijing 100083, PR China; Yue Wang [gzyuewang@126.com] (corresponding author), School of Resources and Environments, Guizhou University, Guiyang 550003, PR China; Wei Du [duwei@ea.c.u-tokyo.ac.jp], Department of Earth Science and Astronomy, The University of Tokyo, Tokyo 153-8902, Japan.