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History of tropical limnology parallels the development of temperate zone limnology Only marginal attention given to we

Crisman, T.L. and W.J. Streever. 1996. The legacy and future of tropical limnology. In: Perspectives in Tropical Limnology , Schiemer and Boland (eds.). SPB Academic Publ., Amsterdam: 27-42. History of tropical limnology parallels the development of temperate zone limnology

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History of tropical limnology parallels the development of temperate zone limnology Only marginal attention given to we

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  1. Crisman, T.L. and W.J. Streever. 1996.The legacy and future of tropical limnology.In: Perspectives in Tropical Limnology, Schiemer and Boland (eds.). SPB Academic Publ., Amsterdam: 27-42. • History of tropical limnology parallels the development of temperate zone limnology • Only marginal attention given to wetlands, including floodplains. • Functional ecology of tropical systems is slow to develop and ecosystem level models are rare. • Pantropical meta-analyses are needed to minimize the transfer of inappropriate management techniques based on temperate zone limnological principles.

  2. Lewis, W.M. 2000

  3. Latitudinal distribution of lake surface area (Herdendorf 1990) Proportions of natural lake type in the tropics (Lewis 1996)

  4. Latitudinal trends in (– – –) maximum and (——) annual minimum irradiance (adapted from Lewis 1987).

  5. Illustration of the latitudinal distribution of lake types based on mixing. Change in the density of water that accompanies a change in temperature of 1°C. Lewis 2000

  6. Warmer water • Higher annual average temperature of epilimnion • More rapid nutrient cycling • More rapid photosynthetic response to nutrients • Higher annual average temperature of hypolimnion • High rates of microbial metabolism • Rapid nutrient regeneration • Rapid oxygen removal • Lower oxygen levels due to warmer water • Management issues regarding anoxia important in tropics • The potential for eutrophication to degrade water quality is higher in the tropics • Eutrophication can occur more easliy, produce more severe symptoms, and be more prolonged in the tropics.

  7. Lewis, W.M. 2000

  8. Lewis, W.M. 2000

  9. Differing probabilities for type and severity of nutrient limitation at (——) tropical and (– – –) temperate latitudes. For the temperate lakes sampled randomly during the growing season, the frequency distribution for nutrient limitation is most heavily weighted toward phosphorus, although some lakes under some conditions will be limited by nitrogen or closely balanced between phosphorus and nitrogen limitation. For tropical lakes, the frequency distribution is shifted toward a predominance of nitrogen limitation, although some phosphorus limitation can also be found. Lewis 2000

  10. Brylinsky and Mann 1973

  11. Aquatic macrophytes can play a very important role in nutrient processing

  12. Lewis, W.M. 2000

  13. Biodiversity very high in tropical terrestrial environments, ancient large tropical lakes and large tropical rivers. In aquatic systems, in general, diversity similar to temperate lakes but note that • Plankton (phyto and zoo) have not been explored as much in the tropics • Larger species of zooplankton lacking in tropics • Benthic communities poorly known • Fish faunas are more diverse and abundant in the tropics and have strong affiliation with riverine fish faunas. • Lacustrine fish production may be depressed (especially in reservoirs).

  14. Information gaps in tropical aquatic ecology(Crisman and Streever 1996) • Microbial loop, hindering our understanding of mineralization and nutrient cycling rates • Benthic macro-invertebrates, limiting their use as water quality indicators in the tropics • Ecosystem functional aspects (conceptual food webs, energy and nutrient flows) • Streams, ponds and wetlands are understudied but heavily impacted by humans. • Abiotic contamination is poorly studied in the tropics in spite of cases of massive pollution (metals, pesticides) • Understanding of the impact of biotic contamination (exotic species) is, at best, spotty and based on short-term studies. • Ecosystem models, needed to develop predictive management plans, are essentially not available.

  15. Tropical Wetlands: the forgotten systems(see Gottgens and Fortney 2004) • Depleting at an alarming rate. • Paradigms developed for temperate zone wetlands do not always apply • Co-evolution of plants and animals • Growing season • Flood pulse • Importance of fish • Wetland resilience to disturbance • Wetlands are commonly integrated in the traditional economy of the regional society • Science in not keeping up with the rate of wetland degradation.

  16. The End

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