Showing papers by "Oregon State University published in 1981"

Quantifying vesicular-arbuscular mycorrhizae: a proposed method towards standardization *

Abstract: SUMMARY A standard method for the quantification of root colonization by vesicular-arbuscular (VA) mycorrhizal fungi is needed. From the examination of roots from three different host species, the estimation of the percentage of the length of root segments containing VA mycorrhizal fungal structures was found to be more accurate than the determination of the percentage of root segments with VA mycorrhizal fungal structures. It was no more time consuming, and was not influenced by segment size. Examination of a minimum of seven samples, each with 25 randomly selected 0 5 to 1 0 cm root segments, was needed for confidence limits to be within 10 % of the mean. It is proposed that, for the sake of comparability between studies, this procedure be

Effects of canopy modification and accumulated sediment on stream communities.

Abstract: Small streams differing in sediment composition were compared in logged and forested reaches to determine effects of accumulated fine sediment on stream communities under different trophic conditions. Three stages of forest community succession were studied in the Cascade Mountains: Recently clear-cut areas without forest canopy (5–10 years after logging); second-growth forest with deciduous canopy (30–40 years after logging); and old-growth coniferous forest (>450 years old). One stream with mostly coarse sediment (56–76% cobble) and one with more fine sediment (5–14% sand and 23–53% gravel) were contrasted for each successional stage. In general, streams traversing open clear-cuts had greater rates of microbial respiration, and greater densities or biomasses of aufwuchs, benthos, drift, salamanders, and trout than did the shaded, forested sites regardless of sediment composition. We conclude that for these small Cascade Range streams, changes in trophic status and increased primary productivity...

On Some Criteria for Estimating the Order of a Markov Chain

Abstract: Tong (1975) has proposed a procedure for estimating the order of a Markov chain based on Akaike's information criterion (AIC). In this paper, the asymptotic distribution of the AIC estimator is derived and it is shown that the estimator is inconsistent. As an alternative to the AIC procedure, the Bayesian information criterion (BIC) proposed by Schwarz (1978) is shown to be consistent. These two procedures yield different estimated orders when applied to specific samples of meteorological observations. For parameters based on these meteorological examples, the AIC and BIC procedures are compared by means of simulation for finite samples. The results obtained have practical implications concerning whether, in the routine fitting of precipitation data, it is necessary to consider higher than first-order Markov chains.

Microcultural study of bacterial size changes and microcolony and ultramicrocolony formation by heterotrophic bacteria in seawater.

Abstract: With a microculture technique and time-lapse, phase-contrast photomicrography, it was possible to follow the division of individual cells and the development of microcolonies of bacteria in freshly collected marine water samples. A certain number of marine bacteria, upon inoculation onto a nutrient rich agar surface, displayed an increase in size as well as a high growth rate. Other bacteria were identified as very small marine bacteria (ultramicrobacteria). These had a very slow growth rate when inoculated onto a nutrient-rich agar surface. These latter cells formed very small microcolonies (ultramicrocolonies), and cell size did not increase significantly. These two types of marine heterotrophs could be described in terms of zymogenous and autochthonous bacteria, a concept used by Winogradsky for describing soil microorganisms. Images

The Ecology of Seabird Feeding Flocks in Alaska

Abstract: --Seabirds commonly gather into mixed-species flocks to feed on fish schools and other concentrations of prey. We group Alaskan and Washington seabird feeding flocks into three types on the bases of flock size and longevity and the nature of the food source. Small, short-lived flocks over tightly clumped prey are called Type I; larger (5,000+ individuals), longer-lasting flocks over less tightly clumped and less reactive prey are called Type II; Type III flocks form where zooplankton and other organisms are concentrated by downwelling. Birds participating in the flocks are assigned to four functional groups (some species fit into two groups): catalysts (larids and shearwaters) are highly visible birds that other birds watch and follow to food sources; divers (alcids, loons, cormorants) exploit the food sources underwater by pursuit diving; kleptoparasites (jaegers and gulls) steal food from other flock members; and suppressors (shearwaters and cormorants) interfere behaviorally with the feeding of other flock members by reducing the effective prey availability. Most flocks occurred within a few kilometers of shore. Type I flocks on the Washington coast averaged larger, lasted longer, and contained more species than Alaskan Type I flocks. The Washington and Alaska flocks contained about the same number of locally breeding species, but the Washington flocks also contained several migrant species that breed elsewhere in North America. Both contained shearwaters, migrants from the southern hemisphere, but the shearwaters were much more important in the Alaskan flocks. Black-legged Kittiwakes and shearwaters (catalysts) initiated most Alaskan flocks and were important in the development of flocks initiated by other birds. Once a flock was initiated, it grew until the food source became unavailable or until the local pool of prospective flock members was exhausted. The divers were able to discriminate from considerable distances between kittiwakes feeding on single fish and kittiwakes feeding on fish schools and approached only the latter. The various species tended to occupy characteristic positions within Type I flocks. Gulls and kittiwakes were central, and the various divers took peripheral positions. Kleptoparasitism by jaegers did not appear to influence Type I flock organization. Shearwaters, the most important suppressors, sometimes pursuit-plunged into fish schools and euphausiid shoals in such numbers that the prey concentrations were drastically reduced, scattered, or driven downward in seconds, and other birds were then unable to feed. Type II flocks were divisible into two groups, one consisting largely of kittiwakes and shearwaters and feeding on capelin, and the other dominated by shearwaters and feeding on pelagic crustaceans. Kleptoparasitism by Pomafine Jaegers in the capelin-based Type II flocks was frequent and differed from the kleptoparasitism of solitary birds in that the jaegers preferentially attacked birds carrying fish in their bills. Suppression appeared unimportant in capelin-based Type II flocks but probably kept alcids and gulls from joining the crustacean-based flocks. In some island groups Type III flocks occurred daily. They were less regular in structure and composition than Type I or Type II flocks. Kleptoparasitism by gulls and kittiwakes tended to keep puffins and other alcids on the edges of the flocks. The alcids' underwater approaches to the fish schools from the sides may have tended to keep the schools compact and near the surface. It has been hypothesized that the 437 The Auk 98: 437-456. July 1981 438 HOFFMAN, HEINEMANN, AND WIENS [Auk, Vol. 98 antipredator function of schooling by baitfish involves predator satiation and the difficulty of locating schools. Schooling does not function as. a deterrent to aerial predators in the same way that it does to swimming ones, however. Either birds are less important as predators, or schooling confers a different advantage in escaping aerial predation. Apparently, fish schools can escape rather quickly from bird flocks by descending away from the surface out of visual contact. Received 8 January 1980, accepted 12 February 1981. FISH-EATING and other seabirds in most of the world's oceans exploit fish schools and other clumped food sources in multispecies flocks. These flocks often include several species that feed differently (Gould 1971, Scott 1973, Sealy 1973) but sometimes in a complementary manner. If indeed the birds use complementary tactics when feeding together, the assemblages may be tightly interacting, coevolved systems. We studied the arian communities of the temperate and subarctic northeast Pacific Ocean to discern how intense, consistent, and obligatory such feeding interactions are. We surveyed the geographic and hydrographic distributions of flocks in our study areas and characterized them by structure, species composition, and food

An analysis of sinking rates of natural copepod and euphausiid fecal pellets1

Abstract: where L and D are the cylinder length and diameter, ps is the particle density, and SL. and p are the fluid viscosity and density. This relationship is compared with published data on the settling velocities of cylindrical fecal pellets produced by euphausiids and copepods. The agreement between data and the equation is very good. The analysis further permits the indirect evaluation of the fecal pellet density. A mean density fi, = 1.22 g*cm-” was so determined, which corresponds almost exactly to the one reliable direct measurement of fecal pellet density (1.23 g.cm-“). A second equation is available that can be used if the fecal pellets are ellipsoidal or oval rather than cylindrical.

Animal Welfare Act

Abstract: Initially the major emphasis of this legislation was to protect owners of cats and dogs from the theft of their animals, many of which were found to be sold for experimental purposes. The 1970 amendments broadened the coverage to include all species of animals, not just cats and dogs, and to include animals which are pets or are used for exhibition purposes. These amendments, as did the amendments of 1976, gave added emphasis to the recognition of the sale, purchase, transportation, housing, care, handling and treatment of animals used for research purposes, or as pets or for exhibitions, as a significantly large interstate commercial operation. There was a need to insure humane care and treatment of these animals.

A Multiple Objective Nurse Scheduling Model

Abstract: The authors present a model for the nurse scheduling problem which works in two phases. In the first phase, the nurses are assigned their day-on/day-off pattern for the two-week scheduling horizon by a goal programming model which allows for consideration of the multiple conflicting objectives inherent in scheduling a nursing staff. The second phase makes specific shift assignments through the use of a heuristic procedure. The two-phase approach results in considerable reductions in problem size, thus reducing the solution effort. Extensions to the basic model are also examined.

Color Degradation in an Ascorbic Acid-Anthocyanin-Flavanol Model System

Abstract: Interactions between ascorbic acid, pelargonidin-3-glucoside, and catechin were studied in pH 3.4 citrate-phosphate buffer at 20°C under anaerobic and oxygenated conditions. Changes in anthocyanin pigment, ascorbic acid, dehydroascorbic acid, and catechin were quantitatively measured during 130 days storage along with Hunter color parameters, browning, and polymeric color. Ascorbic acid had a statistically significant effect on all parameters, including anthocyanin loss under both oxygen and nitrogen environments, catechin loss, increase in browning and polymeric color, decrease in Hunter “a” value and increase in Hunter L value. Ascorbic acid bleached anthocyanin pigment and also induced browning. There is evidence that anthocyanin pigment and ascorbic acid degrade through a direct condensation mechanism.

Patterns of primary productivity and biomass in a coastal upwelling region

Abstract: Average distributions of chlorophyll α during upwelling in areas of smooth bathymetry off Oregon have been computed from historical data. Chlorophyll concentrations in cross-shelf sections over the Oregon continental shelf (44°40′N) were similar to those in cross-shelf sections off northwest Africa during JOINT-1 studies but differed from those in similar sections over an adjacent narrow region of the Oregon shelf (44°55′N to 45°12′N). The fact that larger concentration differences can occur along short sections of one coastline than between upwelling regions half a world apart bears on the time and space scales of sampling and might have bearing on the support and distributions of other trophic levels. Relationships between the local winds and the broader-scale Bakun (1975) upwelling indices were used to classify various phytoplankton biomass and primary productivity distributions according to whether they were in strong upwelling steady state, weak upwelling steady state, or one of two transition states. The upwelling steady state conforms to the ‘upwelling event’ scale (about 3 to 10 days) of Walsh, Whitledge, Kelley, Huntsman and Pillsbury (1977) and the transition state of approximately one-day duration might specify the critical scale for driving the upwelling off Oregon. Under strong steady-state upwelling in early summer a single band of high primary productivity and biomass develops in the surface layer parallel to the bottom contours, but under similar upwelling conditions in later summer a two-celled zonal circulation occurs and two parallel bands develop. Our strong upwelling distributions are discussed in light of current models of the Oregon upwelling system. Maintenance of biological properties through time in the upwelling bands is also discussed. Under weak steady-state upwelling the primary productivity and biomass bands are farther inshore or immediately against the coast. Productivity in the weak upwelling bands can be twice that of the strong upwelling bands and often 20 times that in surrounding water. Under transient conditions in which the local winds are favorable for strong upwelling but the slower-responding Bakun index indicates weak upwelling, chlorophyll distributions change within a day to resemble distributions during strong steady-state upwelling. Under transient conditions in which the local winds weaken dramatically but the Bakun index still indicates strong upwelling, chlorophyll concentrations are high and widely distributed throughout the upwelling region.

Variability in the upper ocean during MILE. Part II: Modeling the mixed layer response

Abstract: The Mixed Layer Experiment (MILE) was an examination of the upper-ocean response to meteorological forcing. In Part I of this paper ( Davis, deSzoeke, Halpern and Niiler , 1981, Deep-Dea Research, 28, 1427–1451) temperature and velocity variability observed at two moorings, and the concurrent atmospheric forcing, were described. The one-dimensional heat budget closed satisfactorily and the low-frequency variability of wind stress and upper-ocean transport agreed qualitatively. In this paper, various aspects of the observed ocean response to wind forcing are modeled. For low frequencies a linear statistical model relating wind stress and currents is found; it describes wind-driven velocities parallel to the expected Ekman transport and decreasing with depth. On time scales long compared with a tidal period the rate of change of vertically integrated potential energy agrees well with 0.5 ϱu ∗ 3 , where u ∗ is the friction velocity in water. The response to wind forcing is also simulated using a one-dimensional mixed-layer model based on parameterizing the potential energy balance in terms of ϱu ∗ 3 and turbulent energy production by the interaction of velocity shear and the entrainment stress. Simulations of the MILE data indicate that both processes are important, the latter primarily during the start of wind events. This model also reproduces the major features of the observed statistical relationship between winds and currents.

Genetic control for sibling recognition

Abstract: The ability to distinguish between kin and non-kin is critical to current theories of altruistic behaviour and kin selection1. Hamilton1 predicted that individuals would behave differently towards one another depending on the genetic relatedness between them. When either proximity to or familiarity with kin is a good predictor of relatedness, the mechanism by which favouritism towards kin is accomplished may not require special kin recognition abilities2,3. However, if proximity and familiarity are poor predictors of kinship, favouritism (hence increases in inclusive fitness4) could only be achieved by the differential recognition of kin and non-kin. We have previously shown that Cascades frog (Rana cascadae) tadpoles reared with siblings prefer to associate with siblings over non-siblings5. The present study is the first to report that totally naive individuals (R. cascadae tadpoles) prefer to associate with siblings over non-siblings. Because tadpoles were separated before hatching and reared apart from other individuals, results suggest that the ability of these tadpoles to discriminate between siblings and non-siblings has some innate component.

The advective flux of heat by mean geostrophic motions in the Southern Ocean

Abstract: A method that is independent of choice of reference level is advanced for calculating, from standard hydrographic data, advective oceanic heat flux by mean geostrophic motions. The method depends on the ability to choose a path of constant vertically averaged potential temperature (reference temperature). It was applied to a collection of historical hydrographic data from the Southern Ocean. A circumpolar path with reference temperature 1.3°C that closely follows the mean position of the Antarctic Polar Front was chosen. The advective geostrophic heat flux across this path was calculated to be 0±23×1013 W. The standard error (and bias, which was found to be small) of this calculation was estimated from a statistical model of correlation of ocean variability that seems appropriate to the way the data are sampled in space and time. The wind-driven Ekman heat flux was calculated at −15×1013 W, that is, equatorward. To balance Gordon's estimate of sea to air heat transfer of 30×1013 W south of the Polar Front, a compensating poleward flux of +45±30×1013 W is postulated. Eddy heat flux seems a prime candidate for accomplishing this flux.

Latitudinal variation in intertidal algal community structure: the influence of grazing and vegetative propagation.

Abstract: The hypothesis that sea urchin grazing and interactions with turf-forming red algae prevent large brown algae from forming an extensive canopy in the low intertidal zone of southern California was tested with field experiments at two study sites. Experimental removal of sea urchins resulted in rapid algal recruitment. Crustose coralline algae which typically dominate the substratum in areas with dense urchin populations were quickly overgrown by several species of short-lived green, brown and red algae. The removal of urchins also significantly increased the recruitment of two long-lived species of large brown algae (Egregia laevigata and Cystoseira osmundacea at one study site and E. laevigata and Halidrys dioica at the other). The experimental plots at both sites were eventually dominated by perennial red algae.

Federal Insecticide, Fungicide, and Rodenticide Act

Abstract: As can be seen in the above chronology, pesticides have been a subject of legislation for a considerable time. The law reported here relates to pesticide registration, protection of the environment, control of the use of pesticides during food production and the health and safety of persons who apply them or otherwise may be exposed to them. It complements the Federal Food, Drug, and Cosmetic Act which is concerned with residues of pesticide chemicals remaining in or on foods after use in production. Discussion of pesticides is deferred to Chapter 44 so the two acts may be viewed together.

Klebsiella planticola sp. nov.: A new species of enterobacteriaceae found primarily in nonclinical environments

Abstract: The nameKlebsiella planticola sp. nov. is proposed for a group of organisms isolated primarily from botanical and daquatic environments. Both numerical and molecular taxonomy techniques show that the species belongs within the genusKlebsiella and that it is distinct from other described species of the genus. The new species has 3 biogroups.K. planticolla is phenotypically identical toK. pneumoniae in classical biochemical tests, but it is distinguishable fromK. pneumoniae based on its ability to grow at 10°C and its inability to produce gas from lactose at 44.5°C. Additional reactions that can be used in combination with the temperature criteria includel-sorbose fermentation and ability to utilize hydroxy-l-proline as a sole carbon source. Strain V-236 (ATCC 33531; CDC 4245-72) is the type strain of the new species.

Ecological Analysis of Species Introductions into Aquatic Systems

Abstract: The introduction of new species into aquatic communities to increase fish production is a management technique that often has created more problems than it has solved. In large measure, this is due to the inability to correctly predict impact. Loop analysis is a tool of systems analysis and may be useful in predicting systems behavior of an aquatic community once an introduction is made, using the limited information usually available. Case histories of two lake systems examined by loop analysis suggest that nutrient-poor systems are most sensitive and become unstable after exotics become established. Rules developed by entomologists to guide selection of predators for biological control systems can be adapted for fisheries management. The “ideal” candidate for aquatic introduction is coadapted with some members of the new system, has a narrow niche breadth, is easily controlled if it escapes from the system, and is free of exotic diseases and parasites.

Sedimentary basins of the Peru continental margin: Structure, stratigraphy, and Cenozoic tectonics from 6°S to 16°S latitude

Abstract: approved: L. D. Kuim The morphology and shallow structure of the Peru continental margin has been mapped using bathymetric and seismic reflection profiles from 6°S to l6°S latitude. Other geophysical and geological data are used to constrain interpretations of the margin's deeper structure and to relate the offshore to onshore Andean geology. Two prominant structural ridges, subparallel to onshore Andean trends, control the distribution of the offshore Cenozoic sedimentary basins. The Coastal Cordillera which surfaces north of 6°S and south of 14°S latitude can be traced onto the offshore as an Outer Shelf High (OSH); it is evidently cored with Precambrian and Paleozoic metasediments and crystalline rocks. A series of shelf basins are situated between the Coast Range/OSH and the Andean Cordillera: from north to south, these are the Sechura, Salaverry, and East Pisco Basins. A second set of upper slope basins flanks the Coast Range/OSH to the southwest, limited seaward by an Upper Slope Ridge (USR) of deformed sediment: Redacted for Privacy from north to south, these are the Trujillo, Lima, and West Pisco Basins. The Yaquina Basin lies within divergent arms of the USR. The shelf and upper slope basins are set on continental massif. An anastamosing network of elongate ridges and ponded sediments is the surficial expression of the subduction complex, which apparently begins just seaward of the USR. The effect of the late Paleocene/Eocene Andean orogeny has been extrapolated offshore as a distinct interface of seismic velocity in the Salaverry Basin. Though Cenozoic marine sedimentation in the shelf basins did not begin until after this event, sedimentation in the upper slope Trujillo Basin may have been more continuous through the early Tertiary. In the Trujillo Basin, the bulk of the nearly 4 km thick sedimentary section is of Paleogene age, while in the adjoining upper slope Lima Basin to the southeast, th bulk of the nearly 2 km thick sedimentary section is of late Miocene or younger age. Apparently, post-Oligocene tectonism caused uplift, deformation, and a gross reduction of sedimentation in the Trujillo Basin; this event is evidenced by boundaries of differential structural deformation in seismic reflection profiles. In middle to late Miocene time, while orogenic activity affected the inland Andean Cordillera, the upper slope Lima Basin subsided and began its depositional record. Unconformities in shelf basins apparently reflect the inland tectonism at this time. The boundarybetween the Lima and Trujillo Basins, and between the contrasting styles of upper slope tectonic movement, is near 9.5°S latitude, coincident with the present day intersection of the Mendana Fracture Zone with the

Influence of dietary fatty acids on the incidence of mammary tumors in the c3h mouse.

Abstract: Statistical techniques have been used to establish the extent to which the incidence of spontaneous mammary tumors in C3H mice could be associated with the levels of individual fatty acids in their diets. Eleven different fats and oils and nine mixtures of these fats and oils were selected so that the levels of the nine major fatty acids varied over a reasonable range and were not highly correlated with one another. Tumor incidence was observed in mice raised on diets containing 10% of these different fats. Multiple regressions have been calculated, expressing tumor incidence or time to tumor as a function of the levels of nine fatty acids, four saturated and five unsaturated, of the dietary lipids. Increased tumor incidence and decreased time to tumor were observed when increasing levels of linoleate (18:2) replaced the eight other fatty acids in the diet while the other polyunsaturated fatty acid, linolenate (18:3), had little effect on tumor incidence. Four saturated fatty acids, laurate (12:0), myristate (14:0), palmitate (16:0), and stearate (18:0), were studied, with only the latter showing a significant effect. Increasing levels of stearate were associated with decreased tumor incidence and increased time to tumor. There was also a suggestion that erucic acid (22:1) reduced tumor incidence, but oleic acid (18:1) produced no significant effect.