FORTY YEARS OF PHYSICAL GEOGRAPHY IN THE JOURNAL

Up to June 1993, 207 articles on physical geography have been published in the Malayan Journal of Tropical Geography (MJTG) (1953–57), Journal of Tropical Geography (JTG) (1958–79) and the Singapore Journal of Tropical Geography (SJTG) (1980–93). These articles are examined initially in terms of their sub-fields (Biogeography, Climatology, Geomorphology, Hydrology, and Soils), area of focus (the tropics, Africa, America, East Asia, South Asia, Southeast Asia excluding Malaysia and Singapore, Malaysia, Singapore, and Southwest Pacific) and the area of origin of the authors. The more significant papers in the sub-fields are indicated. Various factors influencing the contributions to the Journal and some insights on the contributions of local staff (Singapore and Malaysia) are also given. The significance of the Journal as an avenue for local and foreign authors and for papers on physical geography in the tropics is briefly evaluated.     

Organic carbon release by phytoplankton and bacterial reassimilation

The release of organic carbon by phytoplankton and its reassimilation by bacteria were studied in Lake Geneva during four daily kinetics, using¹⁴C techniques. Gentamycin was used to suppress bacterial activity. Size fractionation was used to measure¹⁴C fixation in 2 particulate fractions (≥1 μm and 0.2 to 1 μm) and in a third fraction: dissolved organic carbon. Measurements of bacterial biomass and¹⁴C glucose uptake as the H¹⁴CO ₃ ⁻ uptake by samples prefractionated before incubation showed that the whole algae were retained on 1 μm pore size Nuclepore filters, but bacteria were retained on 1 μm and 0.2 μm filters. Concentration of 20 μg.ml⁻¹ gentamycin resulted in incomplete bacterial inhibition while phytoplankton was affected. Phytoplankton released less of 20% of its photoassimilated carbon of which a large proportion was utilized by bacterioplankton.     

Vermicomposting of domestic waste by using two epigeic earthworms (Perionyx excavatus and Perionyx sansibaricus)

The composting potential of two epigeic earthworms (P. excavatus and P. sansibaricus) was studied in 2002 to breakdown the domestic waste under laboratory conditions. The experimental container with P. sansibaricus showed maximum mineralization and decomposition rate than that of P. excavatus. Except for exchangeable K (it was higher (P = 0.004) in a container with P. excavatus), the domestic waste processed by P. sansibaricus showed about 6% more total nitrogen (P = 0.002) and about 7% more available P (P = 0.269) at the end than by P. excavatus. As compared with the initial level organic C content as well as C:N ratio showed a considerable reduction that was noted higher in substrate with P. sansibaricus than those by P. excavatus (organic C, t-test: P = 0.870; C:N ratio, t-test: P = 0.002). The growth (biomass increase) and reproduction parameters such as mean individual live weight, maximum individual growth rate (mg wt./worm/day), number of cocoons and reproduction rate (cocoon/worm/day) were higher in bedding with P. sansibaricus. The maximum earthworm mortality was in vermibed having P. sansibaricus (～50% higher than by P. excavatus) (t-test: P = 0.423), since both species did not show a drastic difference in waste mineralization rate, but comparatively, P. excavatus exhibited better growth and reproduction performance, which further support the suitability of the species for large scale vermiculture operations.     

A Modified Form of Mild-Slope Equation with Weakly Nonlinear Effect

Nonlinear effect is of importance to waves propagating from deep water to shallow water.Thenon-linearity of waves is widely discussed due to its high precision in application.But there are still someproblems in dealing with the nonlinear waves in practice.In this paper,a modified form of mild-slope equa-tion with weakly nonlinear effect is derived by use of the nonlinear dispersion relation and the steady mild-slope equation containing energy dissipation.The modified form of mild-slope equation is convenient to solvenonlinear effect of waves.The model is tested against the laboratory measurement for the case of a submergedelliptical shoal on a slope beach given by Berkhoff et al,The present numerical results are also comparedwith those obtained through linear wave theory.Better agreement is obtained as the modified mild-slope e-quation is employed.And the modified mild-slope equation can reasonably simulate the weakly nonlinear ef-fect of wave propagation from deep water to coast.     

Process and mechanism of arable land change in Hebei Province during the past 50 years

1 Introduction Arable land is the core of land resources and its dynamic change seriously affects regional sustainable development. Hebei Province, with a large population, is an agricultural province. With the highspeed economic development, population growth and urbanization, a great amount of arable land has been lost and the land shortage has become more serious. Therefore, arable land change and its driving forces should be studied in order to realize the sustainable agricultural develo…     

Croatia — “a small country for a great vacation”

Croatia is a country of tourism, and this is primarily due to its position by the warm Adriatic Sea, its varying and picturesque landscapes, its diverse and generally favorable climate for tourism, its rich Mediterranean and Central European cultural heritage and its proximity to the leading European consumer countries.In the international tourism market, Croatia presents itself with the slogan A Small Country for a Great Vacation, because its 4.8 million inhabitants and surface area of 56,538 km² place Croatia in the ranks of the world's smaller countries. Its significance is increased by an additional 33,200 km² of territorial waters, of which a large part is considered internal waters because of its location within the limits of a series of islands.The tourism offering of Croatia is very diverse, but its basis is formed by three differing and mutually complimentary regions, through their natural characteristics and cultural heritage: coastal, montane and Pannonian and peri-Pannonian Croatia. The total tourism offering of Croatia includes 900,000 beds, of which over one-fifth are in hotels or similar places, two-fifths are in private rooms and one-third in camps.The tradition of tourism in Croatia is over one hundred years old, and according to the number of foreign tourists it is ranked as the fifth country for tourism in southern Europe.     

Non-elastic tilt of the earth's crust due to meteorological pressure distributions

Summary A typical disturbance observed in the records of tilt measurements performed with horizontal pendulums in a mine at a depth of 145 m below surface, under very constant temperature conditions, has been analysed as to its correlation with the barometric pressure distribution. It is shown that the observed load tilts are not due to elastic deformations of the Earth's crust, but may be ascribed to movements of tectonic blocks of large extension.     

云南东北部拱王山末次冰期

1 Introduction The Gongwang mountains constitute one of the few high m ountains of irrefutable late Pleistocene glaciation in eastern China. This area is one of the m ost extensively studied Quaternary geologicallocationsin eastern China and the interpret…