NABS Plenary: The Abiotic Template in Flowing Waters I
Presiding: T Bullen, U.S. Geological Survey; A Packman, Northwestern University; M R Whiles, Southern Illinois University at Carbondale; W Dodds, Kansas State University
NB11A-01 INVITED 08:00h
NABS Plenary: Linking the Abiotic Environment to Biodiversity in Running Waters
The importance of abiotic factors to the distribution and abundance of species is well known to laypeople, and forms one of the most ancient branches of ecology. Despite the long history of studies on abiotic effects on biodiversity in running waters, there has been much recent activity in the field, and significant challenges remain. We will review recent progress in areas such as collecting data at very large and very small scales of time and space; quantifying and applying abiotic information in models to manage aquatic resources; and mechanistic studies linking the abiotic environment with the biota. We will highlight three great challenges for the future: collaborating with the technologists whose instruments will capture and process detailed information about the abiotic environment; developing statistical and conceptual tools to analyze the large data sets that we will be able to collect; and learning how to apply knowledge of the abiotic environment and the influence of abiotic factors on biotic interactions towards an integrative theory of biodiversity that includes multiple abiotic and biotic variables working at different scales.
NB11A-02 INVITED 08:30h
NABS Plenary: Building Flumes and Flow Tanks: Bringing Streams Indoors
As useful analogs of natural streams, a variety of types of flumes or flow tanks have proven useful. But the relationship between the requirements of a project and specific design and construction choices may be far from obvious, and commercial versions of assured performance are not (yet) available. The user may need the simplest, quickest, and cheapest design for a particular investigation or, alternatively, a versatile piece of general laboratory equipment. The present talk will begin with the choice of overall configuration and construction materials. It will then consider specifics of one design of wide applicability relative to complexity and cost. In particular, guidance will be provided for estimating such things as maximum useful speed, motor choice, and propeller rotation rate.
http://sicb.org/dl/biomechanics.php3
NB11A-03 09:00h
Morning, Noon and Night: DOM, Photochemistry and the River Continuum
The role of light in structuring stream ecosystems is a major theme of the River Continuum Concept (RCC). A specific hypothesis was that the chemical diversity of dissolved organic material (DOM) increases downstream as the production of DOM by phototrophs (algae and macrophytes) contributes to DOM coming from runoff of forested catchments. Studies have shown that direct photochemical processes influence the chemistry of the DOM pool, changing its bioavailability and its reactivity with trace metal and organic contaminants. Recent research has shown that a major DOM fraction, fulvic acid, can be used as electron acceptors by heterotrophic microorganisms in reducing environments and that reduced fulvic acid can then be used as an energy source by other microorganisms. The hydrologic transport of reduced DOM from reducing environments, such as hyporheic zones, to oxidizing environments in streams may influence ecosystem function. Thus, the chemical diversity and biogeochemical reactivity of DOM in stream ecosystems are dynamic, with changes occurring over a day-night cycle being superimposed upon seasonal changes in light regime and in hydrologic regime. Incorporating these dynamic processes into the broad scale of the RCC may be useful in understanding the effects of changes in water quality, land use and hydrologic regime.
NB11A-04 INVITED 09:30h
NABS Plenary: The Physical Template and its Control of Stream Ecosystem Processes
The physical template strongly influences ecosystem processes in streams. Among the physical properties exerting control on ecosystem processes are discharge regime, substratum characteristics, light levels, and water flow paths at both the channel and catchment scales. Ecosystem processes such as whole-system rates of metabolism and reach-scale nutrient cycling respond to variations in these physical properties at several temporal scales. This talk will explore these physical template-ecosystem process linkages via several examples from studies of small streams.