The effect of the mermithid parasite Gasteromermis sp. (Nematoda: Mermithidae) on the drift behaviour of its mayfly host, Baetis bicaudatus (Ephemeroptera: Baetidae): a trade-off between avoiding predators and locating food

1996 ◽  
Vol 74 (10) ◽  
pp. 1907-1913 ◽  
Author(s):  
Sarah A. Vance
Keyword(s):  
Water Column ◽  
Stream Channels ◽  
Body Angle ◽  
Trade Off ◽  
Food Location ◽  
Fish Predators ◽  
Baetis Bicaudatus ◽  
Late Instar ◽  
Mermithid Nematode ◽  
Experimental Stream

This study reports alterations in the drift behaviour of mayfly nymphs (Baetis bicaudatus) infected with the mermithid nematode parasite Gasteromermis sp. with respect to (i) their exposure to drift-feeding trout predators and (ii) the efficiency with which they locate food. Experimental stream channels and benthic and drift samples were combined to investigate drift behaviour. The drift behaviour of earlier instars did not differ between parasitized and unparasitized nymphs. Infected late-instar nymphs, however, drifted less frequently, drifted higher in the water column, and swam more frequently while drifting. Neither drift distances nor body angle while drifting were altered. Parasitized nymphs showed a reduction in food-location success in heterogeneous stream channels. The drift alterations therefore reduce both the exposure of the host to fish predators and the efficiency with which it locates food. The mayfly population is effectively divided into two groups: unparasitized nymphs (in which drift behaviour is of consequence to mayfly fecundity) and parasitized nymphs (in which drift behaviour is of consequence to mermithid survival and fecundity). It is suggested that locating food may be less important to the parasite, while the risk of trout predation may be higher for drifting parasitized individuals. Both of these factors would favour the parasite influencing its host to adopt lower drift frequencies.

Effects of woody debris on the growth and behaviour of brown trout in experimental stream channels

1998 ◽  
Vol 76 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Karl Sundbaum ◽  
Ingemar Näslund
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Woody Debris ◽  
Feeding Activity ◽  
Control Channel ◽  
Invertebrate Drift ◽  
Stream Channels ◽  
Gravel Bed ◽  
Brown Trout Salmo Trutta ◽  
Experimental Stream

We examined the effects of woody debris on the growth and behaviour of brown trout (Salmo trutta) in experimental stream channels. Two types of habitat were used in the study: a complex habitat created by placing woody debris on a gravel bed and a uniform habitat consisting of a gravel bed only. The experiment was run both outdoors with wild fish that fed on natural invertebrate drift and indoors with hatchery fish that were fed artificial food. In both treatments most of the fish lost mass. In all trials, however, the fish in the woody debris channel lost less mass than the fish in the control channel. Study of the fishes' behaviour revealed less swimming activity, less aggression, and less feeding activity in the woody debris channel than in the control channel. The results of this study indicate that the presence of woody debris decreases intraspecific competition through visual isolation, allowing fish to reduce aggressive interactions and energy expenditure.

Swimming behavior of juvenile giant scallop, Placopecten magellanicus, in relation to size and temperature

1991 ◽  
Vol 69 (8) ◽  
pp. 2250-2254 ◽  
Author(s):  
J. L. Manuel ◽  
Michael J. Dadswell
Keyword(s):  
Water Column ◽  
Significant Relationship ◽  
Size Range ◽  
Shell Height ◽  
Swimming Behavior ◽  
The Body ◽  
Placopecten Magellanicus ◽  
Body Angle ◽  
The Mean ◽  
Increasing Temperature

Juvenile scallops (shell height 4–35 mm) were stimulated to swim in an aquarium using a whelk, and their swimming was recorded and analyzed using a videocassette recorder. Scallops ascended in the water column in straight, spiral, or twisting patterns, and the majority never swam horizontally. Two types of swimming were observed. Stable swimming, with a consistent body angle (the angle that the scallop makes with the horizon), was recorded over the size range of scallops examined. In stepwise swimming, the body angle alternated between steep (98 ± 13 (SD)) and more horizontal angles (51 ± 9°). Stepwise swimming was observed among the smaller (mean ± SD = 8 ± 3 mm) scallops. Maximum and mean velocities were positively correlated with both shell height and temperature. Clap rate (Cr) increased with increasing temperature (Cr = 0.29T (°C) + 1.3). Body angle expressed a significant relationship with shell height. Below 10 mm shell height the mean angle was 82°; between 30 and 35 mm the mean angle was 38°.

Residence Time in Hyporheic Bioactive Layers Explains Nutrient Uptake in Streams

2021 ◽  
Author(s):  
Eugènia Martí ◽  
Angang Li ◽  
Susana Bernal ◽  
Brady Kohler ◽  
Steven A. Thomas ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Water Column ◽  
Residence Time ◽  
Hyporheic Zone ◽  
Morphological Characteristics ◽  
Subsurface Water ◽  
Water Residence Time ◽  
Stream Channels ◽  
Nutrient Spiraling ◽  
Tracking Model

<p>Human activities negatively impact water quality by supplying excessive nutrients to streams. To investigate the capacity of streams to take up nutrients from the water column, we usually add nutrients to stream reaches, calculate the fraction of added nutrients that is taken up, and identify the environmental conditions controlling nutrient uptake. A common idea is that nutrient uptake increases with increasing water residence time because of increased contact time between solutes and organisms. Yet, water residence time only partially explains the temporal and spatial variability of nutrient uptake, and the reasons behind this variability are still not well understood. In this talk I’ll present a study which shows that good characterization of spatial heterogeneity of surface-subsurface flow paths and bioactive hot spots within streams is essential to understanding the mechanisms of in-stream nutrient uptake. The basis of this study arises from the use and interpretation of nutrient uptake results from the Tracer Additions for Spiraling Curve Characterization (TASCC) method. This model has been rapidly adopted to interpret in-stream nutrient spiraling metrics (e.g, nutrient uptake) over a range of concentrations from breakthrough curves (BTCs) obtained during pulse solute injection experiments. TASCC analyses often identify hysteresis in the relationship between spiraling metrics and concentration as nutrient concentration in BTCs rises and falls. The mechanisms behind these hysteresis patterns have yet to be determined. We hypothesized that difference in the time a solute is exposed to bioactive environments (i.e., biophysical opportunity) between the rising and falling limbs of BTCs causes hysteresis in TASCCs. We tested this hypothesis using nitrate empirical data from a solute addition combined with a process-based particle-tracking model representing travel times and transformations along each flow path in the water column and hyporheic zone, from which the bioactive zone comprised only a thin superficial layer. In-stream nitrate uptake was controlled by hyporheic exchange and the cumulative time nitrate spend in the bioactive layer. This bioactive residence time generally increased from the rising to the falling limb of the BTC, systematically generating hysteresis in the TASCC curves. Hysteresis decreased when nutrient uptake primarily occurred in the water column compared to the hyporheic zone, and with increasing the distance between the injection and sampling points. Hysteresis increased with the depth of the hyporheic bioactive layer. Our results indicate that the organisms responsible for nutrient uptake are confined within a thin layer in the stream sediments and that the bioactive residence time at the surface-subsurface water interface is important for nutrient uptake. I will end the talk illustrating how these findings can have important implications for in-stream nutrient uptake within the context of restoration practices addressed to modify the hydro-morphological characteristics of stream channels.</p>

Studies on the bionomics of mermithid nematode parasites of blackflies in Newfoundland

1975 ◽  
Vol 53 (9) ◽  
pp. 1324-1331 ◽  
Author(s):  
Barry A. Ebsary ◽  
Gordon F. Bennett
Keyword(s):  
Life Cycle ◽  
Host Specificity ◽  
Larval Stage ◽  
Early Spring ◽  
Next Generation ◽  
Parasite Life Cycle ◽  
Nematode Parasites ◽  
Late Instar ◽  
Mermithid Nematode ◽  
Single Larva

Neomesomermis flumenalis is a univoltine nematode infecting the simuliids Prosimulium fuscum/mixtum during the winter months and the first (early spring) generations of the summer simuliids, primarily Simulium venustum, in May and early June. Infection of simuliid larvae occurred when water temperatures were 4–12 °C. Data extrapolated from late-instar larvae and pupae indicated that less than 0.03% and 0.06% of the P. fuscum/mixtum and S. venustum adults, respectively, were infected with this parasite, which is primarily a parasite of larval simuliids. Adult simuliids were not considered to be the source of the next generation of mermithids. The apparent host specificity of N. flumenalis is attributed to the close synchronization of the parasite life cycle with the life cycle of those simuliid species which overwinter in the larval stage and develop at temperatures less than 12 °C; temperatures above this level tend to be lethal to the preparasitic mermithids and simuliid species developing in the summer are thus not infected by this species. Male mermithids were more numerous than females in the Prosimulium populations but females outnumbered male mermithids in the S. venustum populations. When only a single mermithid parasitized a simuliid larva, the nematode was always a female; when more than one nematode parasitized a single larva, the nematodes were usually males.

Worthenopora: an unusual cryptostome (Bryozoa) that looks like a cheilostome

1991 ◽  
Vol 65 (4) ◽  
pp. 648-661 ◽  
Author(s):  
Steven J. Hageman
Keyword(s):  
North America ◽  
Water Column ◽  
Secondary Structures ◽  
Growth Patterns ◽  
Wall Structure ◽  
Illinois Basin ◽  
Trade Off ◽  
Growth Sequence ◽  
Column Space ◽  
Medial Plane

Worthenopora is a Mississippian cryptostome bryozoan genus with certain characteristics that so closely resemble those of some cheilostomes (Jurassic–Recent) that previous bryozoan experts speculated whether Worthenopora should be assigned to the order Cheilostomata. This raises the question of possible affinities between cryptostomes (class Stenolaemata) and cheilostomes (class Gymnolaemata). Based on wall structure, growth sequence, zooecial shape, and secondary structures such as stylets, Worthenopora is here shown to be a stenolaemate, assignable to the suborder Ptilodictyina with other bifoliate cryptostomes. Although the exterior appearance of Worthenopora superficially resembles some cheilostomes, it represents rather limited divergence from more typical bifoliate growth patterns. Additionally, presence of characteristics such as elongate zooecia with thin exozones, cuticular medial plane, and distinctive exterior ridges justifies retention of the monogeneric family Worthenoporidae. Three species (W. spatulata, W. spinosa, and W. valmeyerensis), known only from North America and primarily restricted to the Illinois Basin, are recognized. Analysis of apertural spacing in these species suggests a trade-off between feeding efficiency and occupation of water-column space. Worthenopora valmeyerensis is considered a hypermorphic derivative of W. spinosa.

Are host–parasite interactions influenced by adaptation to predators? A test with guppies and Gyrodactylus in experimental stream channels

Oecologia ◽  
2012 ◽  
Vol 170 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Felipe Pérez-Jvostov ◽  
Andrew P. Hendry ◽  
Gregor F. Fussmann ◽  
Marilyn E. Scott
Keyword(s):  
Stream Channels ◽  
Host Parasite Interactions ◽  
Host Parasite ◽  
Experimental Stream

Responses of cytochrome P4501A in freshwater fish exposed to bleached kraft mill effluent in experimental stream channels

1995 ◽  
Vol 52 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Laura A. Bankey ◽  
Peter A. Van Veld ◽  
Dennis L. Borton ◽  
Larry LaFleur ◽  
John J. Stegeman
Keyword(s):  
Chlorine Dioxide ◽  
Channel Catfish ◽  
Largemouth Bass ◽  
Control Fish ◽  
Stream Channels ◽  
Pulp Bleaching ◽  
Cytochrome P4501a ◽  
Kraft Mill Effluent ◽  
Kraft Mill ◽  
Experimental Stream

Cytochrome P4501A induction was used to evaluate exposure of fish to bleached kraft mill effluent in experimental stream channels. Immunodetectable P4501A and associated ethoxyresorufin-O-deethylase (EROD) activity were elevated in largemouth bass (Micropterus salmoides) and channel catfish (Ictalurus punctatus) throughout 263 days of exposure to 8% and 4% effluent from a mill that used 70% chlorine dioxide substitution for chlorine in the pulp bleaching process. In largemouth bass, P4501A was elevated as high as 55-fold over control fish. Large temporal and species variations were observed in enzyme levels and activity. Levels of chlorinated organic compounds present in effluent also varied throughout exposures. However, there was no apparent relationship between P4501A and any of those compounds measured. P4501A and EROD in channel catfish declined to control levels within seven days after transfer of fish to clean water or after terminating introduction of effluent into the channels. In another exposure, induction was observed in largemouth bass at 4 and 12% effluent after the mill began using oxygen in the delignification process and 100% substitution of chlorine dioxide for chlorine.

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