Effects of inter-organism interactions in biofouling on microtopographic surfaces

<p>In-stream faunal organisms constantly interact with their habitat to modify its physical and hydraulic properties. However, little is known about how sediment-organism interactions could modify the hyporheic exchange. Previous experimental work investigating the effects of the activities of faunal organisms on exchange across the sediment-water interface has been largely conducted in small mesocosms or infiltration columns that do not represent the lotic environment adequately. Therefore, the experimental findings from these studies may not be transferable to flowing water environments (e.g., streams). Our previous experimental work demonstrated that sediment reworking by macroinvertebrates could significantly alter the hyporheic flux, mean residence times, and depth of exchange in streambeds. In this work, we explore how sediment-organism contact time influence the effect of the activities of model organisms, Lumbriculus variegatus, on the hyporheic flow regime. We conduct laboratory experiments in re-circulating flumes subject to different sediment reworking times (5 and 10 days). The hyporheic flow characteristics in these flumes were studied by conducting dye tracer tests after the bed sediments were reworked. Deposition of fecal pellets and holes/burrows dug by sample organisms were visible at the bed surface in both the experimental flumes. The flume reworked for a longer time exhibited higher hyporheic flux, longer median/mean residence times, and deeper depth of solute penetration compared to the flume reworked for a shorter period. The modification of hyporheic flow regime to different degrees depending on the sediment reworking times has direct relevance to the biogeochemistry in hyporheic zones, and thus on the overall quality of surface and sub-surface waters. We advocate that more intensive laboratory experiments and field investigations must be conducted to support the findings from our study and advance our understanding of the role of the activities of faunal organisms on fluvial ecosystem functioning.</p>

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Acidification and Toxicity of Metals to Aquatic Biota

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f85-251 ◽

1985 ◽

Vol 42 (12) ◽

pp. 2034-2049 ◽

Cited By ~ 306

Author(s):

P. G. C. Campbel ◽

P. M. Stokes

Keyword(s):

Metal Speciation ◽

Biological Response ◽

Metal Availability ◽

Ph Effects ◽

Type I ◽

Aquatic Biota ◽

Dominant Effect ◽

Biological Surfaces ◽

Freshwater Acidification ◽

Organism Interactions

Acidification of freshwaters can in principle influence metal–organism interactions in at least two ways: the decrease in pH may affect metal speciation in solution, or it may affect biological sensitivity at the level of the cell surface. We considered the possible effects of environmental acidification (pH 7–4) on (1) metal speciation in solution, (2) metal adsorption at biological surfaces, and (3) metal uptake by and toxicity to aquatic biota. Attention was focused on some 10 metals of potential concern in the context of freshwater acidification (Ag, Al, Cd, Co, Cu, Hg, Mn, Ni, Pb, Zn). For the four metals (Al, Cu, Hg, Pb) predicted to manifest speciation changes in the range pH 7–4, confirmatory experimental data are available for two (Cu, Pb). In the six remaining cases predicted to show little sensitivity to pH changes in this range, supporting experimental evidence exists for four metals (Ag, Cd, Mn, Zn). A pH-dependent biological response is documented over a realistic range of H+ and metal concentrations for 6 of the 10 metals considered (Al, Cd, Cu, Zn, and to a lesser extent, Hg and Pb). These six metals fall into two groups: those for which a decrease in pH results in a decreased biological response (type I behavior: Cd, Cu, Zn) and those for which the dominant effect of acidification is to increase metal availability (type II behavior: Pb). Data for the remaining two metals (Al, Hg) clearly reveal pH effects, but the results are too few and too inconsistent to allow generalizations.

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Pesticide-Organism Interactions

EDIS ◽

10.32473/edis-pi080-2005 ◽

2019 ◽

Vol 2005 (6) ◽

Author(s):

Frederick M. Fishel

Keyword(s):

Cooperative Extension ◽

Cooperative Extension Service ◽

Extension Service ◽

Publication Date ◽

Original Publication ◽

University Of Florida ◽

Agricultural Sciences ◽

Living Organisms ◽

Organism Interactions

This guide addresses the various responses of living organisms to pesticides. This document is PI-43, one of a series of the Pesticide Information Office, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date June 2005.

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