Ventilatory Behavior Research Articles

Automated biomonitors ? first line of defense

Automated biomonitors operate on a real-time basis and utilize living organisms as the sensors. Traditionally, chemical monitors have been used to assess water quality. However, biological monitors respond to a greater number of toxic conditions. An overview of the various automated biomonitors, assessed by the types of biological sensors employed, is presented. The sensors used include bacteria, algae, invertebrates, and fish. Of all the systems, those monitoring the ventilatory behavior of fish have evolved the furthest with respect to their research, development, commercial availability, and field testing.

The Effect of Aquatic O₂ Levels on Diving and Ventilatory Behavior in Soft-Shelled (Trionyx spiniferus), Stinkpot (Sternotherus odoratus), and Mud Turtles (Kinosternon subrubrum)

Diving and ventilatory behavior were observed in three species of bimodally breathing turtles: Trionyx spiniferus, Sternotherus odoratus, and Kinosternon subrubrum. These turtles have high, intermediate, and low reliances on aquatic gas exchange, respectively. Turtles with access to normoxic air were filmed in normoxic, hypoxic, and hyperoxic water. Ninety percent of all dives were shorter than 20 min. Despite differences in the partitioning of respiratory gas exchange, dive duration in normoxia did not differ among species. Dive duration was directly proportional to aquatic PO₂ in soft-shells and independent of aquatic PO₂ in mud turtles. Stinkpots had consistently but not significantly shorter dives in normoxia. Aquatic PO₂ had no effect on the ventilation patterns of soft-shells. Regardless of PO₂, soft-shells typically engaged in one breathing bout, during which one breath was taken, per emersion period. Stinkpots and mud turtles underwent more bouts ofbreathingper emersion period and took more breaths per breathing bout than did soft-shells. Stinkpots in normoxia took more breaths than in hypoxia or hyperoxia, while mud turtles showed no response to aquatic PO₂. These results agree with previous research that found soft-shells to be the least reliant of the three species on aerial respiration. These results also indicate that aquatic PO₂ is an important factor in the regulation of diving and ventilatory behavior in at least some bimodally breathing turtles.

Rapid detection of sublethal toxicity using fish ventilatory behavior

AbstractSignificant changes in bluegill sunfish ventilation were observed at chronically toxic levels of various substances in under 1 h of exposure and usually within 15 min of exposure. A different ventilation response was observed between the heavy metal compounds and the chlorinated hydrocarbon substances. The response to metals zinc and cadmium was characterized by: (a) decrease in signal amplitude and (b) increase in Type I (large volume) coughs or gill purges. The response to chlorinated hydrocarbons was characterized by: (a) increase in erratic movement, (b) increase in gill purges and (c) increase in ventilatory frequency. Our results suggest that fish ventilatory monitoring can provide a powerful tool for rapidly assessing sublethal as well as acute toxicity on a real‐time basis. Furthermore, the type of response generated may be indicative of the type of toxicant in the environment.

Ventilatory Reactions of the Lugworm Arenicola marina (L.) to Ambient Water Oxygenation Changes: A Possible Mechanism

The ventilation of the lugworm was studied at different controlled PO₂ values in the ambient water at 20 C. When ventilation in normoxia is taken as a reference value, hyperoxia (300 and 500 Torr) depressed ventilation, mild hypoxia increased ventilation slightly, severe hypoxia depressed ventilation, and extreme hypoxia arrested ventilation. At each controlled PO₂, 30-s exposures to oxygen-saturated water (PO₂ ca. 700 Torr) were performed-the oxygen tests-and the subsequent ventilation were measured. Oxygen tests led to no change of ventilation in hyperoxia, a fall of ventilation in normoxia and mild hypoxia, and an increase of ventilation in severe and extreme hypoxia. This ventilatory behavior is best explained by assuming, as a base ventilation, the low ventilation observed in hyperoxia that corresponds to the spontaneous activity of a pacemaker located in the nerve cord. The decrease of ambient PO₂ toward normoxia and mild hypoxia activates a chemoreflex ventilatory drive, and ventilation increases...

VENTILATORY RESPONSES OF BLUEGILL SUNFISH TO SUBLETHAL, FLUCTUATING EXPOSURES TO HEAVY METALS (Zn++ and Cu++)1

ABSTRACT Minicomputer interfaced, continuous, noncontact sensing of the ventilatory behavior of the bluegill (Lepomis macrochirus) was used to investigate the response to exposure to solutions of copper and zinc under various modes of application. The results of these studies indicate that fish respond to sublethal concentrations of these toxicants by increasing the average ventilatory rate as well as decreasing the amplitude of the ventilatory signal. Appropriate statistics for the analysis of these data are also described.

Use of Box and Line Plots to Assess Fish Ventilatory Behavior in Biological Monitoring Systems

Ventilatory signals from 12 bluegill (Lepomis macrochirus) sunfish were collected with the aid of an on-line minicomputer as part of a biological monitoring system. Our results from three experiments demonstrate a potential for applying these graphic techniques to on-line biomonitoring systems.Key words: biological monitoring, ventilatory behavior, biomonitoring, bluegill sunfish, breathing, water quality, box plots, line plots

Application of Time–Series Intervention Analysis to Fish Ventilatory Response Data

The development of environmental monitors based on ventilation behavior of fishes has produced large masses of data for which no standard analytical procedures exist. This report demonstrates the application of time–series models to this type of data. It also demonstrates the use of intervention analysis to determine the reaction to changes in water quality. Intervention analysis is a powerful statistical tool that allows for great flexibility in the type of response that can be investigated. In this report it is used to determine the ventilatory reaction of the bluegill (Lepomis macrochirus) to sublethal concentrations of zinc sulfate applied in fluctuating intermittent exposures.Key words: intervention analysis, time–series models, Lepomis, ventilatory behavior, biomonitoring

Industrial effluent monitoring incorporating a recent automated fish biomonitoring system

An automated, continuous biological monitoring facility which is in operation at a U.S. Army ammunition manufacturing plant is described. The system monitors the ventilatory behavior of bluegill sunfish,Lepomis macrochirus Raf, to assess the quality of two wastewater discharges with the aid of an on-line minicomputer system. Certain chemical/physical parameters are also monitored automatically on a continuous basis. The capability for detecting unapproved discharges is discussed. The overall concept of this system and discussion of its potential for economically monitoring water and wastewater discharges, both automatically and continuously, are presented.

A COMPARISON OF METHODS AND INSTRUMENTATION OF BIOLOGICAL EARLY WARNING SYSTEMS1

ABSTRACT: Rapid biological information systems using aquatic organisms to monitor water and waste water quality have only recently begun to develop technologically for practical on‐site applications. One approach which has been demonstrating its feasibility recently monitors the ventilatory behavior of fish to assess, for example, the quality of drinking water supplies and industrial waste water discharges. A comparison of the basic strategies of the various biological monitoring systems making use of this concept is presented. In addition, the applications and potential utilization of these systems are discussed.

Ventilatory responses to exercise in divers and non-divers

The initial (neurogenic) and steady-state ventilatory responses to three levels of treadmill exercise (+10% grade; 1.6, 3.2 and 4.8 km/hr) were studied in divers, sedentary non-divers, and non-diving athletes. The steady-state ventilatory responses of divers were lower than the sedentary group, significantly so at 3.2 and 4.8 km/hr where the differences were 20% of the sedentary values. The initial responses of divers were also lower, but with marginal significance. Both initial and steady-state responses of athletes were intermediate between divers and sedentary non-divers. Both divers and athletes tended to have higher pa(q, and lower R values than sedentary non-divers; divers more so than athletes. Divers showed a markedly slower and deeper breathing pattern than the other two groups. We suggest that the unusual ventilatory behavior of divers is not fitness-related, reflects more than reduced chemosensitivity, and may involve a conditioned response phenomenon.

Respiratory Adaptations in Marine Mammals

This paper is a discussion of some of the possible structural and functional modifications of the lung which represent adaptations in mammals living in the sea. Lung capacities of marine mammals seem to be larger than terrestrial mammals especially if they are compared on a lean weight basis. It is proposed that at least in some this represents an important increase in buoyancy which enables these mammals to rest at sea. The importance of the lung as an O2 store during dives is considered, and it seems that it would be important only to those species that have a low breath-hold tolerance. In their case the O2 present in the fully inflated lung is from four times to equal that in the blood. In those species with a large breath-hold tolerance the lung O2 store is a small fraction of blood stores. Several experiments are discussed which indicate that during dives to depth gas exchange between the blood and lungs is low. One of the reasons suggested is compression collapse of the alveoli. This occurs because of the apparent rigidity of the airways which even in the terminal segments possess an unusual amount of muscular or cartilaginous support. The reinforcement insures that during compression the airways will not occlude and trap gas in the alveoli. In fact, in some species, especially otariids and cetaceans, the airways seem overly strong and an additional function is suggested. Studies of mechanical properties of sea lion and whale lungs show that they may be capable of high expiratory flow rates at low volumes. This feature of the lung would make possible an exchange of a large gas volume in very short periods. Such an ability is consistent with the ventilatory behavior of many marine mammals.

Chemoreflexes in breathing.

Chemoreflexes in breathing.