Freshwater Ecosystems Revitalizing Educational Programs in Limnology (1996) / Chapter Skim
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Linkages Among Diverse Aquatic Ecosystems: A Neglected Field of Study
Linkages Among Diverse Aquatic Ecosystems: A Neglected Field of Study
Pages 203-217
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From page 203... ...
INTRODUCTION Aquatic scientists commonly combine a variety of scientific approachesphysical, chemical, biological and ecological in the study of their particular ecosystem, whether it be stream, lake, wetland, or ocean. It has been far less common, even unusual, for these same aquatic scientists to investigate in any detailed way the interactions of the type of ecosystem in which they specialize with other types of aquatic ecosystems, despite the fact that all are linked through the hydrological cycle and in many other ways.
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From page 204... ...
Given the great success and significance of such nutrient-cycl~ng studies, which are very widely cited in the literature of ecosystem ecology and biogeochemistry, a strong argument can be made for broadening greatly such vertically oriented research on the linkages among aquatic ecosystems to include other aspects of ecosystem function, diverse examples of which are given in the following pages. There are, however, impediments to the pursuit of such studies.
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From page 205... ...
EXAMPLES OF INTERDISCIPLINARY AND INTERECOSYSTEM STUDIES The nature and importance of interdisciplinary and interecosystem studies can be illustrated most clearly by a series of examples that demonstrate, first, the linkages among disciplines and, second, the functional couplings among different types of inland aquatic ecosystems.
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From page 206... ...
that physical stratification of shallow, highly productive lakes in summer, by isolating their deeper waters from contact with the atmosphere, is responsible for the severe depletion of oxygen that makes those deeper lakes uninhabitable by many organisms, including a number of fish species and their prey. Likewise, the freezing phase of the annual temperature cycle in northern latitudes may lead to oxygen depletion throughout shallow lakes and therefore to the winterkill that often decimates sport fisheries.
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From page 207... ...
have shown that upwelling of circumneutral ground water rich in calcium bicarbonate is vital to the development of patterned peatlands in northern landscapes. This upwelling water forms distinct fen water tracks that become dominated by sedges and flow through the peatlands in a way that separates them sharply from the ovoid, acid sphagnum bogs that are the other distinctive feature of such landscapes.
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From page 208... ...
Analysis of carbon isotopes has shown that particulate organic detritus eroded from tundra peatlands is a significant source of nutrition for food chains leading to fish and ducks in nearby ponds and lakes (Schell,1983~. This sort of information provides a better understanding of food chain dynamics in freshwater habitats, a matter of particular concern for indigenous peoples and sport fishermen.
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From page 209... ...
If, as expected, climate warming becomes a serious environmental problem in the next century (Intergovernmental Panel on Climate Change, Working Group 1, 1992) , the Great Plains of North America will likely see a sharp decline in the number of prairie potholes combining wetlands suitable for the breeding of ducks with open water suitable for their feeding.
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From page 210... ...
In all of these examples, restriction of studies to a single type of ecosystem would also restrict, to a very significant extent, both our thinking about and our understanding of serious environmental problems. IMPORTANT QUESTIONS FOR FUTURE RESEARCH ON THE LINKAGES AMONG AQUATIC ECOSYSTEMS More attention to interecosystem linkages can be justified only if truly important research questions, both fundamental and practical, can be asked about them.
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From page 211... ...
has provided a general account of effects on carbon cycling, but much remains to be done in terms of the cycles of nutrients and toxins and their effects upon species composition, productivity, food chains, etc. The invasion of North American wetlands by the Eurasian exotic purple loosestrife (Thompson et al., 1987)
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From page 212... ...
MECHANISMS FOR FOSTERING CLOSER TIES AMONG STUDENTS OF DIFFERENT AQUATIC ECOSYSTEMS If scientists are to be encouraged to study functional couplings among the diverse types of aquatic ecosystems, increased attention to both mechanisms and incentives for bringing them together will be required. That attention must focus not only on research itself, but also on professional recognition of the importance of generalist ecosystem studies and on the teaching of future generations of aquatic scientists.
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From page 213... ...
It is not enough, however, merely to bring scientists from different backgrounds together; they must also be brought to focus directly in individual sessions on the functional couplings among wetlands, streams, lakes, and oceans rather than simply to compare ecosystem processes such as net primary production, food chain dynamics, cycling of nutrients and toxins, and emissions of trace gases, valuable as such environmental and biotic comparisons may be. Professional recognition for ecosystem generalists who study functional couplings is also important.
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From page 214... ...
Initiatives should therefore be developed at this time, In both teaching and research, to attract scientists to their study. A broader graduate training, developing thorough familiarity with more than one type of ecosystem, would be greatly conducive to thinking about the functional couplings among ecosystems.
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From page 215... ...
In review. The chemistry of streams in southwestern and central Nova Scotia, with particular reference to the influence of dissolved organic carbon from wetlands.
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From page 216... ...
Minnesota Fish Consumption Advisory.
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From page 217... ...
1992. Gradient-dominated ecosystems: Sources and regulatory functions of dissolved organic matter in freshwater ecosystems.
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