Tropical lakes

Tremendous variability exists in turnover patterns and date of onset. Polar lakes warm later in spring and cool sooner in fall than similar lakes in tropical regions. Ice may only melt away from some lakes for two months a year, resulting in slow fish growth compared to warmer climates. High altitude lakes also warm later and cool sooner than equivalent low altitude lakes. Tropical, high altitude lakes lose heat continuously, do not develop layers, and overturn continually, whereas sub-tropical, low altitude lakes that never freeze only layer in summer and turn over in winter. 

Shallow lakes are open water bodies a few metres deep. Only considered foe temperate and tropical regions in polar and boreal regions it is difficult to separate shallow lakes from bogs and fens. 

Fig. 10. GC MS TIC traces for total extracts of (a) a tropical lake sediment, and (b) epicu-ticular wax from a dominant reed growing in the shallow areas of the lake (analyzed as TMS). Numbers and symbols as in Fig. 9, 4P = dibutyl phthalate contaminant, IS = internal standard.

Lakes, rivers, swamps, and marshes - common in temperate areas - contribute little to the diversity of natural products. Abundant dull-green grass and dull-colored fish and moUusks characterize lakes and rivers, in contrasts with the vivid colors of tropical fish and seaweeds. Haplosclerid sponges are occasionally abundant in freshwater, but their secondary metabolism is limited to demospongic acids (Dembisky 1994), in contrast with the variety of metabolites from marine sponges in the same order. Where not for cyanobacteria (which are as rich of unusual metabolites as the marine strains), tropical amphibians, and aquatic fimgi, freshwater ecosystems would have passed unnoticed in this book. 

Huang, Y. Murray, M. Eglinton, G. Metzga, P. (1995A) Sacredicene, a novel monocyclic C33 hydrocarbon from sediment of Sacret lake, a tropical freshwater lake, Mount Koiya. Tetrahedron Lett., 36,5973-5976. 

Variation among Sampling Sites. Dissolved humic substance samples from seven end-member environments were isolated for study. Autochthonous inputs to DOM were expected to dominate in Big Soda Lake and in Island Lake, which is a groundwater-sustained eutrophic lake in the sandhills of western Nebraska. Allochthonous inputs to DOM from a swamp environment predominate in the Suwannee River. They also dominate in the Calcasieu River in western Louisiana, but the proportion of swampland is much lower there. The Temi River is a tropical blackwater tributary of the Orinoco River in Venezuela, where allochthonous inputs dominate. The entire Sagavanirktok River basin is located north of the tree line on the North Slope of Alaska a mixture of allochthonous and autochthonous inputs was expected for the various rivers and lakes in this basin. Lastly, Hidden Lake Creek, which is the outlet of Hidden Lake on the Kenai Peninsula of Alaska, was sampled to determine if nutrient inputs from decaying salmon were contributing to primary production and autochthonous inputs to DOM. 

Legumes are found in locations from the tropics to beyond the Arctic Circle and are most frequent and diverse in tropical rain forests and savannahs. They provide major sources of food, fibers, fodder, timber, drugs and many other products, and have done so since ancient times. Seeds of legumes have been found as tomb offerings in the earliest Egyptian and Tigris-Euphrates civilizations and from prehistoric and medieval lake dwelling sites in Europe. 

Waters of oceans/seas near the tropics have the highest salinity. Near the equator and the poles, the salinity is low. Salinity of inland seas and lakes is high. Why Salinity of some inland lakes are given below. 

Islam, Md.R., Lahermo, P., Salminen, R. et al. (2000) Lake and reservoir water quality affected by metals leaching from tropical soils, Bangladesh. Environmental Geology, 39(10), 1083-89. 

Cross SL, Seltzer GO, Fritz SC, Dunbar RB (2001) Late Quaternary climate change and hydrology of tropical South America inferred from an isotopic and chemical model of Lake Titicaca, Bolivia and Peru. Quat Res 56 1-9... 

Gardner, W. S., J. F. Cavaletto, H. A. Bootsma, P. J. Lavrentyev, and F. Troncone. 1998. Nitrogen cycling rates and light effects in tropical Lake Maracaibo, Venezuela. Limnology and Oceanography 43 1814-1825. 

Figure 6.1. Ecosystem area and soil carbon content to 3-m depth. Lower Panel Global areal extent of major ecosystems, transformed by land use in yellow, untransformed in purple. Data from Hassan et al. (2005) except for Mediterranean-climate ecosystems transformation impact is from Myers et al. (2000) and ocean surface area is from Hassan et al. (2005). Upper Panel Total C stores in plant biomass, soil, yedoma/permafrost. D, deserts G S(tr), tropical grasslands and savannas G(te), temperate grasslands ME, Mediterranean ecosystems F(tr), tropical forests F(te), temperate forests F(b), boreal forests T, tundra FW, freshwater lakes and wetlands C, croplands O, oceans. Data are from Sabine et al. (2004), except C content of yedoma permafrost and permafrost (hght blue columns, left and right, respectively Zimov et al., 2006), and ocean organic C content (dissolved plus particulate organic Denman et al., 2007). This figure considers soil C to 3-m depth (Jobbagy and Jackson, 2000). Approximate carbon content of the atmosphere is indicated by the dotted lines for last glacial maximum (LGM), pre-industrial (P-IND) and current (about 2000). Reprinted from Fischlin et al. (2007) in IPCC (2007). See color insert.

Pa PACE PAGES PAHO PALE PAR PARCS PBL PCM PDV PhA PIK PIRA PIRATA POC POLDER Partial pressure in the atmosphere Permafrost And Climate in Europe Pilot Analysis of Global EcoSystems Pan American Health Organization Paleoclimates of Arctic Lakes and Estuaries Photosynthetic Active Radiation Paleoenvironmental ARCtic Science Planetary Boundary Layer Parallel Climate Model Pacific Decadal Variability Phytogenic Aerosol Potsdam-Institut fur Klimafolgenforschung Petroleum Industry Research Associates Pilot Research moored Array in the Tropical Atlantic Permanganate Oxidizable Carbon POLarization and Directionality of the Earth s Reflectances Princeton Ocean Model... 

Bacteria inhabit every environment on the planet earth. They can be found in temperate as well as tropical areas, in deserts, ice caps, alkali lakes, oceans and hot springs. In one gram of soil, approximately 108 bacteria are present11 and these are estimated to represent over 10000 species. It is estimated that 50% of the biomass on this planet is microbial. Microorganisms represent by far the richest repertoire of functionally and chemically diverse producers of secondary metabolites in nature. 

Biomes are a group of closely related ecosystems (see below). Terrestrial biomes include tundras, taigas, temperate forests, deserts, grasslands, and tropical rain forests. Major aquatic biomes are freshwater swamps, marshes and bogs, lakes and rivers, estuaries, inter-tidal zones, coastal oceans and open oceans. 

There are 5 major reservoirs in the Earth system atmosphere, biosphere (vegetation, animals), soils, hydrosphere (oceans, lakes, rivers, groundwater), and the lithosphere (Earth crust). Elemental cycles of carbon, oxygen, nitrogen, sulfur, phosphorus, and other elements interact with the different reservoirs of the Earth system. The carbon cycle has important aspects in tropical forests due to the large amount of carbon stored in the tropical forests and the high rate of tropical deforestation 0acob 1999)-... 

Fisher, T. R., R. D. Doyle, and E. R. Peele. 1988b. "Size-fractionated uptake and regeneration of ammonium and phosphate in a tropical lake." Verhandlungen International Vereinigen Limnologie 23 637-641. 

Melack, J. M. 2001. "Floodplain lakes and reservoirs in tropical and subtropical South America Limnology and human impaas." In The Lakes Handbook, eds. P. O Sullivan, and C. Reynolds (Blackwell Science Ltd., Oxford, U.K.), in press. 

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