A review of various aspects of invertebrate-microbial interactions is presented. Food resources of stream invertebrates are distinguished by particle size (detritus), the presence of chlorophyll (periphyton), and high protein content (macrophytes). Invertebrate functional feeding groups such as shredders, collectors, scrapers, piercers, and predators are discussed. The interactions between temperature and quantity and quality of stream macroinvertebrate food resouces are described. Symbiotic relationships between stream invertebrates and microorganisms are discussed.

Feeding Ecology of Stream Invertebrates

Organic compound emission rates for volatile organic compounds (VOC), gas-phase semivolatile organic compounds, and particle-phase organic compounds are measured from residential fireplace combustion of wood. Firewood from a conifer tree (pine) and from two deciduous trees (oak and eucalyptus) is burned to determine organic compound emissions profiles for each wood type including the distribution of the alkanes, alkenes, aromatics, polycyclic aromatic hydrocarbons (PAH), phenol and substituted phenols, guaiacol and substituted guaiacols, syringol and substituted syringols, carbonyls, alkanoic acids, resin acids, and levoglucosan. Levoglucosan is the major constituent in the fine particulate emissions from all three wood types, contributing 18−30% of the fine particulate organic compound emissions. Guaiacol (2-methoxyphenol), and guaiacols with additional substituents at position 4 on the molecule, and resin acids are emitted in significant quantities from pine wood combustion. Syringol (2,6-dimethoxyphenol) and syringols with additional substituents at position 4 on the molecule are emitted in large amounts from oak and eucalyptus firewood combustion, but these compounds are not detected in the emissions from pine wood combustion. Syringol and most of the substituted syringols are found to be semivolatile compounds that are present in both the gas and particle phases, but two substituted syringols that have not been previously quantified in wood smoke emissions, propionylsyringol and butyrylsyringol, are found exclusively in the particle phase and can be used to help trace hardwood smoke particles in the atmosphere. Benzene, ethene, and acetylene are often used as tracers for motor vehicle exhaust in the urban atmosphere. The contribution of wood smoke to the ambient concentrations of benzene, ethene, and acetylene could lead to an overestimate of the contribution of motor vehicle tailpipe exhaust to atmospheric VOC concentrations.

Measurement of emissions from air pollution sources. 3. C1-C29 organic compounds from fireplace combustion of wood.

Gas- and particle-phase tailpipe emissions from late-model medium duty diesel trucks are quantified using a two-stage dilution source sampling system. The diesel trucks are driven through the hot-start Federal Test Procedure (FTP) urban driving cycle on a transient chassis dynamometer. Emission rates of 52 gas-phase volatile hydrocarbons, 67 semivolatile and 28 particle-phase organic compounds, and 26 carbonyls are quantified along with fine particle mass and chemical composition. When all C_1−C_(13) carbonyls are combined, they account for 60% of the gas-phase organic compound mass emissions. Fine particulate matter emission rates and chemical composition are quantified simultaneously by two methods:  a denuder/filter/PUF sampler and a traditional filter sampler. Both sampling techniques yield the same elemental carbon emission rate of 56 mg km^(-1) driven, but the particulate organic carbon emission rate determined by the denuder-based sampling technique is found to be 35% lower than the organic carbon mass collected by the traditional filter-based sampling technique due to a positive vapor-phase sorption artifact that affects the traditional filter sampling technique. The distribution of organic compounds in the diesel fuel used in this study is compared to the distribution of these compounds in the vehicle exhaust. Significant enrichment in the ratio of unsubstituted polycyclic aromatic hydrocarbons (PAH) to their methyl- and dimethyl-substituted homologues is observed in the tailpipe emissions relative to the fuel. Isoprenoids and tricyclic terpanes are quantified in the semivolatile organics emitted from diesel vehicles. When used in conjunction with data on the hopanes, steranes, and elemental carbon emitted, the isoprenoids and the tricyclic terpanes may help trace the presence of diesel exhaust in atmospheric samples.

Measurement of emissions from air pollution sources. 2. c1 through c30 organic compounds from medium duty diesel trucks

The cyclic transformations of inorganic sulfur compounds in the sediments of a Danish fjord were followed for 2 years. The in situ rate of sulfate reduction measured with a radiotracer technique together with chemical determinations of various sulfur compounds are used to calculate a budget of the complete sulfur cycle. Sulfate reduction rates were high at the sediment surface (25 to 200 nmol SO/sub 4//sup 2 -/ cm/sup -3/ d/sup -1/) and there was still measurable activity at a depth of 1.5 m. Sulfate reduction is also compared with the benthic community metabolism measured as the oxygen uptake rate of the sediment. Sulfate reduction accounted for 53% of the total mineralization of organic matter in the sediment. Only 3% of the sulfide was derived from organic sulfur. Of all the sulfide produced, 10% was precipitated by metal ions within the anoxic sediment while the rest was reoxidized at the surface. The results demonstrate the dynamic nature of the sulfur cycle, with turnover times for sulfate of 4 to 5 months and for free sulfide of 1 to 5 days.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1977.22.5.0814

The sulfur cycle of a coastal marine sediment (Limfjorden, Denmark)1

The composition of any environment or object is determined by a particular balance between material transport processes and chemical reactions within and around it. In the case of marine sedimentary deposits, the dominant agents of mass transport are often large bottom-dwelling animals that move particles and fluids during feeding, burrowing, tube construction, and irrigation. Such biogenic material transport has major direct and indirect effects on the composition of sediments and their overlying waters. In this chapter I review some of what is presently known about these effects, their implications for both chemical and biological properties of a deposit, and how they can be conceptualized in quantitative models.

The Effects of Macrobenthos on Chemical Properties of Marine Sediment and Overlying Water

The density of a deposit-feeding amphipod H&e&z axtecu was varied experimentally in undisturbed sediment cores taken from Marion Lake, British Columbia. Epibenthic algal production, total community respiration, and bacterial oxygen consumption were measured after 4%hr in situ incubation. As density increased community respiration also increased, in a nonlinear manner. Epibenthic algal production was stimulated within the range of natural amphipod densities, but declined at higher densities. Bacterial respiration was stimulated at amphipod densities up to four times those observed in the lake and also declined at higher densities. These data were used to compare microflora production with Hyalella’s daily calorific requirement at various densities. At natural densities, less than 10% of daily microBora production would be required to supply the energy necessary for observed rates of amphipod growth, respiration, and egg production. Fecal pellets produced by HyccE&z were rapidly colonized by microorganisms. Autotrophic microorganisms increased, while respiration of heterotrophic microorganisms and solution decreased organic content of feces. Dissolved organic compounds excreted by Hya2eZla significantly increased the rate of recolonization of fecal material.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1970.15.1.0021

The effect of a deposit‐feeding amphipod on the metabolism of benthic microflora1

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1969.14.5.0801

Similarity of oxygen uptake by benthic communities1

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1971.16.1.0099

Barry T. Hargrave

Papers

The effect of a deposit‐feeding amphipod on the metabolism of benthic microflora1

Similarity of oxygen uptake by benthic communities1

An energy budget for a deposit‐feeding amphipod1