Influence of Overwintering Stresses on Respiration Throughout the Life History of the Freshwater Leech, Nephelopsis obscura

1993 ◽  
Vol 50 (4) ◽  
pp. 841-845 ◽  
Author(s):  
Ronald W. Davies ◽  
V. Kalarani
Keyword(s):  
Life History ◽  
Oxygen Consumption ◽  
Dry Weight ◽  
Low Oxygen ◽  
Nephelopsis Obscura ◽  
Stage 4 ◽  
Metabolic Costs ◽  
History Of ◽  
Flow Through ◽  
Low Oxygen Concentration

The effects of overwintering stresses (low temperature, low oxygen concentration) on the life history patterns of activity-specific oxygen consumption by Nephelopsis obscura were determined using a flow-through respirometer system and compared with leeches hatched and maintained under summer conditions. While resting and active oxygen consumption increased with body dry weight, weight-specific resting (Rm) and active (Ra) oxygen consumption and aerobic scope (AS) decreased with increase in body weight in both winter and summer N. obscura. Rm in winter leeches was higher than in summer leeches, probably reflecting the higher metabolic costs of tissue repair and maintenance after winter stresses. Although Ra and AS in winter leeches were initially lower than in summer leeches, by stage 4, compensation in winter leeches was complete and by stage 6, over-compensation occurred. The effects of overwintering on oxygen consumption and AS persisted throughout the life history and help explain some of the differences in allocation of energy storage observed in winter and summer leeches.

The life history of a tropical dragonfly: Cora marina (Odonata: Polythoridae) in Guanacaste, Costa Rica

1996 ◽  
Vol 12 (4) ◽  
pp. 573-581 ◽  
Author(s):  
Gordon Pritchard
Keyword(s):  
Life History ◽  
Costa Rica ◽  
Hyporheic Zone ◽  
Flight Period ◽  
Low Oxygen ◽  
Wet Season ◽  
Oxygen Conditions ◽  
History Of ◽  
One Year ◽  
Oviposition Sites

ABSTRACTThe life history of Cora marina was followed for one year in two permanent streams at 600 m elevation in Guanacaste National Park; Costa Rica. The water temperature was c. 21°C year-round, but there was a distinct wet-dry seasonality, very little rain falling from January to May. In both streams, C. marina was univoltine. Adults first appeared at the beginning of May and the flight period coincided with the wet season. The availability of water-soaked logs as oviposition sites probably restricts reproduction to the wet season. Eggs hatched from mid-July to December. Recruitment to subsequent larval instars was slow during the wet season but increased at the start of the dry season. Final-instar larvae were collected from March to October. Oviposition in logs above the stream and the ability to live in the low oxygen conditions of the hyporheic zone probably allow eggs and small larvae to survive wet season spates.El ciclo biológico de una libelula tropical: Cora marina (Odonata: Polythoridae) en Guanacaste, Costa Rica.

Assessment of Activity-Specific Metabolism of Aquatic Organisms: An Improved System

1992 ◽  
Vol 49 (6) ◽  
pp. 1142-1148 ◽  
Author(s):  
Ronald W. Davies ◽  
Frederick J. Wrona ◽  
V. Kalarani
Keyword(s):  
Oxygen Consumption ◽  
Individual Variation ◽  
Aquatic Organisms ◽  
Size Classes ◽  
Interspecific Differences ◽  
Nephelopsis Obscura ◽  
Highly Sensitive ◽  
Similar Weight ◽  
Flow Through

An improved flow-through respirometer capable of assessing activity-specific metabolism of aquatic organisms is presented and assessed. The system is highly sensitive and versatile, since it continuously monitors and records activity-specific oxygen consumption readings for periods up to 72 h and is capable of detecting differences in metabolism of individual specimens of similar weight. Using this system, we demonstrated individual variation and intraspecific differences in metabolism between two size classes of the freshwater leech Nephelopsis obscura and interspecific differences between N. obscura and another freshwater leech, Erpobdella montezuma, and compared these findings with the metabolism of the amphipod Hyalella montezuma.

The life history of Branchinecta mackini Dexter (Crustacea: Anostraca) in an argillotrophic lake of Alberta

1977 ◽  
Vol 55 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Graham R. Daborn
Keyword(s):  
Organic Matter ◽  
Life History ◽  
Life Cycle ◽  
Growth Rates ◽  
Dry Weight ◽  
Fairy Shrimp ◽  
Maximum Biomass ◽  
History Of ◽  
Mean Size

The life history of B. mackini was studied in a large argillotrophic lake during 1970–1972. Hatching began immediately after spring thaw and was terminated by rising salinity 10 days to 2 weeks later. Growth rates reached maxima of 1 mm/day at 4 weeks of age and then declined as mean size approached 22–23 mm at 7–8 weeks. Clutch sizes varied as a function of female length. Maximum biomass of 580 mg dry weight/m2 (2700 cal/m2) was reached in late May, of which 3.9% per day was consumed by B. gigas. Source of the energy is presumed to be a bacteria – organic matter complex associated with suspended particles. Life cycle details are compared with other fairy shrimp species and the role of B. mackini in the community is discussed.

Oxygen consumption of a large, cold-adapted frog egg (Ascaphus truei (Amphibia: Ascaphidae))

1977 ◽  
Vol 55 (2) ◽  
pp. 343-348 ◽  
Author(s):  
Herbert A. Brown
Keyword(s):  
Oxygen Consumption ◽  
Pacific Northwest ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Dry Weight ◽  
Developmental Rate ◽  
Low Oxygen ◽  
Cold Adapted ◽  
Wet Weight ◽  
Montane Streams

Female Ascaphus lay a small number of large eggs beneath rocks in cold, montane streams of the Pacific Northwest. Average number of eggs per female is 45 (range, 28 to 64) and average egg diameter is 4 mm (range, 3.5 to 4.5). The large eggs of Ascaphus contain a relatively large amount of nutrients. Average wet weight of a single egg is 37.5 mg and dry weight is 23.7 mg (63% of wet weight). The oxygen consumption rate of embryos during development at 15 °C increases gradually during cleavage (0.25 μl O2/h per embryo) and more rapidly during neurula and postneurula stages (0.60 to 0.90 μl O2/h per embryo) to a value of 1.20 μl O2/h per embryo at vitelline circulation. The cold-adapted eggs of Ascaphus are characterized by large size, slow developmental rate and low oxygen consumption rate.

Relationships between size of stream insects and current velocity

1978 ◽  
Vol 56 (2) ◽  
pp. 178-186 ◽  
Author(s):  
William P. Kovalak
Keyword(s):  
Life History ◽  
Habitat Selection ◽  
Dry Weight ◽  
Growth Cycle ◽  
Head Width ◽  
Differential Growth ◽  
Growth Cycles ◽  
Frequency Distributions ◽  
Stream Insects ◽  
History Of

Size frequency distributions and dry weight – head width relationships for six insect species from two habitats with differing current velocities in the Pigeon River, Michigan, were compared. Early in their growth cycles, Ephemerella subvaria, Ephemerella lata, Rhithrogena jejuna, and Glossosoma nigrior generally were larger at the slow station, but near the end of the growth cycles they generally were larger at the fast station. For Paraleptophlebia mollis, early in the growth cycle size differences between stations were small but near the end of the growth cycles nymphs were larger at the fast station, whereas nymphs of Ephemerella deficiens were slightly larger at the slow station throughout the growth cycle. Larger size at the slow station probably was due to differential growth whereas larger size at the fast station probably was due to differential habitat selection controlled by oxygen requirements.There were no significant differences in dry weight – head width relationships between habitats or between sexes. Sex ratios generally were similar at the two stations and did not deviate appreciably from 50:50.The life history of each species is briefly described.

Life at the top: Lake ecotype influences the foraging pattern, metabolic costs and life history of an apex fish predator

2019 ◽  
Vol 88 (5) ◽  
pp. 702-716 ◽  
Author(s):  
Liset Cruz‐Font ◽  
Brian J. Shuter ◽  
Paul J. Blanchfield ◽  
C. Ken Minns ◽  
Michael D. Rennie
Keyword(s):  
Life History ◽  
Fish Predator ◽  
Metabolic Costs ◽  
History Of ◽  
Foraging Pattern

scholarly journals Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

Microbiology ◽  
2010 ◽  
Vol 156 (4) ◽  
pp. 1052-1059 ◽  
Author(s):  
Ahmad F. Khadem ◽  
Arjan Pol ◽  
Mike S. M. Jetten ◽  
Huub J. M. Op den Camp
Keyword(s):  
Nitrogenase Activity ◽  
Dry Weight ◽  
Low Oxygen ◽  
Chemostat Cultures ◽  
Activity Measurements ◽  
Genes Encoding ◽  
Oxygen Sensitive ◽  
Important Trait ◽  
Low Oxygen Concentration ◽  
Growth Experiments

The ability to utilize atmospheric nitrogen (N2) as a sole nitrogen source is an important trait for prokaryotes. Knowledge of N2 fixation by methanotrophs is needed to understand their role in nitrogen cycling in different environments. The verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ strain SolV was investigated for its ability to fix N2. Physiological studies were combined with nitrogenase activity measurements and phylogenetic analysis of the nifDHK genes, encoding the subunits of the nitrogenase. ‘M. fumariolicum’ SolV was able to fix N2 at low oxygen (O2) concentration (0.5 %, v/v) in chemostat cultures. This low oxygen concentration was also required for an optimal nitrogenase activity [47.4 nmol ethylene h−1 (mg cell dry weight)−1]. Based on acetylene reduction assay and growth experiments, the nitrogenase of strain SolV seems to be extremely oxygen sensitive compared to most proteobacterial methanotrophs. The activity of the nitrogenase was not inhibited by ammonium concentrations up to 94 mM. This is believed to be the first report on the physiology of N2 fixation within the phylum Verrucomicrobia.

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