Seasonal changes in the diel surfacing behaviour of the bimodally respiring turtle Rheodytes leukops

2003 ◽  
Vol 81 (9) ◽  
pp. 1614-1622 ◽  
Author(s):  
Matthew A Gordos ◽  
Craig E Franklin ◽  
Colin J Limpus
Keyword(s):  
Water Temperature ◽  
Seasonal Changes ◽  
Abiotic Factors ◽  
Diurnal Variations ◽  
Freshwater Turtle ◽  
Behavioural State ◽  
Pressure Sensitive ◽  
Diel Fluctuations ◽  
Increased Activity ◽  
Austral Autumn

The purpose of this study was to determine whether a relationship existed between the diel surfacing trends of the bimodally respiring freshwater turtle Rheodytes leukops and daily fluctuations in specific biotic and abiotic factors. The diel surfacing behaviour of adult R. leukops was recorded over four consecutive seasons (Austral autumn 2000 – summer 2001) within Marlborough Creek, central Queensland, Australia, using pressure-sensitive time–depth recorders. Additionally, diurnal variations in water temperature and aquatic PO2 level, as well as the turtle's behavioural state (i.e., active versus resting), were monitored. In autumn and summer, surfacing frequency increased significantly during the daylight hours, with peak levels normally occurring around dawn (0500–0700) and dusk (1700–1900). However, no consistent diel surfacing trend was recorded for the turtles in winter or spring, owing to considerable variation among individual R. leukops. Diurnal surfacing trends recorded for R. leukops in autumn and summer are attributed to periods of increased activity (possibly associated with foraging) during the daylight hours and not to daily variations in water temperature or aquatic PO2 level. Turtles generally remained at a depth greater than 1 m throughout the day, where the effect of diel fluctuations in water temperature (<0.5 °C) and aquatic PO2 level (<15 mm Hg (1 mm Hg = 133.322 Pa)) was considered to be negligible.

Seasonal changes in the diving performance of the bimodally respiring freshwater turtle Rheodytes leukops in a natural setting

2003 ◽  
Vol 81 (4) ◽  
pp. 617-625 ◽  
Author(s):  
Matthew A Gordos ◽  
Craig E Franklin ◽  
Colin J Limpus
Keyword(s):  
Metabolic Acidosis ◽  
Environmental Conditions ◽  
Seasonal Changes ◽  
Physiological State ◽  
Metabolic Cost ◽  
Freshwater Turtle ◽  
Natural Setting ◽  
Aquatic Respiration ◽  
Pressure Sensitive ◽  
Austral Autumn

The objective of this study was to investigate how seasonally fluctuating environmental conditions influence the diving performance of the highly aquatic, bimodally respiring turtle Rheodytes leukops in a natural setting. Over four consecutive seasons (Austral autumn 2000 to summer 2001), the diving behaviour of adult turtles was recorded via pressure-sensitive time–depth recorders within Marlborough Creek, central Queensland, Australia. Short surfacing intervals recorded for R. leukops in winter suggest that the species utilizes aquatic respiration as an overwintering strategy to prevent the development of a metabolic acidosis during the long inactive dives observed during the season. As water temperature increases and aquatic PO2 decreases, R. leukops switches from facultative to obligate air-breathing, presumably because of the increased metabolic cost associated with aquatic respiration under summer conditions. Increases in mean surfacing time from winter to spring and summer are attributed to seasonal changes in behaviour possibly associated with foraging rather than to the physiological state of the turtle, given that no difference in median surfacing time among seasons was observed.

Water temperature, vertical distribution, and risk of ectoparasitism in juvenile sticklebacks

1988 ◽  
Vol 66 (9) ◽  
pp. 2002-2005 ◽  
Author(s):  
Robert Poulin ◽  
Gerard J. FitzGerald
Keyword(s):  
Vertical Distribution ◽  
Water Temperature ◽  
Attack Rate ◽  
Abiotic Factors ◽  
Natural Habitat ◽  
Early Morning ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
Diel Fluctuations ◽  
The Vertical Distribution

We tested the hypothesis that the risk of juvenile sticklebacks (Gasterosteidae) being parasitized by the crustacean ectoparasite Argulus canadensis decreases with increasing water temperature. In the laboratory, juvenile sticklebacks and parasites were acclimated to three different temperatures, 18, 22, and 26 °C. The attack performances of single parasites on groups of 20 fish were measured at each temperature. We found no significant effect of temperature on the attack success (percentage of attacks successful) or the attack rate (number of attacks per minute) of parasites. In addition, we sampled sticklebacks in their natural habitat, salt marsh tide pools, three times per day, when water temperatures were lowest, intermediate, and highest. The relative abundance of parasites on fish (total number of A. canadensis divided by the total number of sticklebacks sampled) was twice as high during midafternoon, when temperature was highest, than in the early morning, when temperature was lowest. Sticklebacks usually swam close to the bottom of tide pools, where parasites were resting, in midafternoon, and at the water surface in the early morning. These changes in the vertical distribution of the fish may result from diel fluctuations in temperature or in other abiotic factors, and small differences in these factors between the bottom and the surface of the pools. Our results indicate that, while it had no direct effects on the attack success and attack rate of the parasites, water temperature, or other abiotic factors, may have indirectly affected the sticklebacks' chances of being parasitized by changing their vertical distribution, and thus their spatial overlap with parasites.

scholarly journals Longitudinal sampling of external mucosae in farmed European seabass reveals the impact of water temperature on bacterial dynamics

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Daniela Rosado ◽  
Raquel Xavier ◽  
Jo Cable ◽  
Ricardo Severino ◽  
Pedro Tarroso ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Microbial Diversity ◽  
Water Temperature ◽  
Abiotic Factors ◽  
Seasonal Effect ◽  
Microbial Composition ◽  
Surrounding Water ◽  
European Seabass ◽  
And Function ◽  
The Impact

AbstractFish microbiota are intrinsically linked to health and fitness, but they are highly variable and influenced by both biotic and abiotic factors. Water temperature particularly limits bacterial adhesion and growth, impacting microbial diversity and bacterial infections on the skin and gills. Aquaculture is heavily affected by infectious diseases, especially in warmer months, and industry practices often promote stress and microbial dysbiosis, leading to an increased abundance of potentially pathogenic bacteria. In this regard, fish mucosa health is extremely important because it provides a primary barrier against pathogens. We used 16 rRNA V4 metataxonomics to characterize the skin and gill microbiota of the European seabass, Dicentrarchus labrax, and the surrounding water over 12 months, assessing the impact of water temperature on microbial diversity and function. We show that the microbiota of external mucosae are highly dynamic with consistent longitudinal trends in taxon diversity. Several potentially pathogenic genera (Aliivibrio, Photobacterium, Pseudomonas, and Vibrio) were highly abundant, showing complex interactions with other bacterial genera, some of which with recognized probiotic activity, and were also significantly impacted by changes in temperature. The surrounding water temperature influenced fish microbial composition, structure and function over time (days and months). Additionally, dysbiosis was more frequent in warmer months and during transitions between cold/warm months. We also detected a strong seasonal effect in the fish microbiota, which is likely to result from the compound action of several unmeasured environmental factors (e.g., pH, nutrient availability) beyond temperature. Our results highlight the importance of performing longitudinal studies to assess the impact of environmental factors on fish microbiotas.

scholarly journals Autecology of Shallow-Water Octocorallia from Mediterranean Rocky Substrata, I. The Banyuls Area

1979 ◽  
Vol 49 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Steven Weinberg
Keyword(s):  
Water Temperature ◽  
Experimental Work ◽  
Ecological Niche ◽  
Water Movement ◽  
Abiotic Factors ◽  
Scuba Diving ◽  
Survival Strategy ◽  
Field Observations ◽  
Southern France ◽  
Juvenile Stages

The autecology of eleven mediterranean octocoral species (3 Stolonifera, 4 Alcyonacea, 4 Gorgonacea) was studied near Banyuls-sur-Mer (southern France). Field observations were carried out by means of SCUBA-diving in forty underwater stations. The ecological amplitude of each species was determined for a number of abiotic factors, viz. water temperature, submarine irradiance, water movement, slope of substratum and sediment. In this way the ecological niche for the different species was defined. The niches of several species partly overlap: the survival “strategy” of these species was defined as “competitivity”. Other species display “specialization”, a strategy by which they avoid competitive situations. A third survival mechanism is “opportunism”, encountered in species which are extremely tolerant with respect to their environment. Although experimental work is needed to determine how niche selection occurs, larval and juvenile stages are considered to be critical in this respect.

scholarly journals Hormonal Regulation of Fish Adaptation to Atypical Fluctuations in Temperature and Oxygen Regime of a Water Body

2019 ◽  
Vol 7 (2) ◽  
pp. 1
Author(s):  
Oleksandr Potrokhov ◽  
Oleg Zinkovskyi ◽  
Mykola Prychepa ◽  
Yurii Khudiiash
Keyword(s):  
Water Temperature ◽  
Oxygen Concentration ◽  
Fish Species ◽  
Hormonal Regulation ◽  
High Water ◽  
Fish Growth ◽  
Increase Water Temperature ◽  
Growth And Change ◽  
Species Specific ◽  
Increased Activity

Recently, the water temperature significantly exceeded the climatic norms for the studied region of Ukraine. Water is heated to 30ºC with a decrease in the concentration of dissolved oxygen in shallow water. In this connection, the change in the hormone content in the blood plasma of carp, roach, rudd, perch and ruff in response to these factors has been studied. Most of the fish species studied in June respond by increasing the cortisol content in the blood by 1.2–3.3 times to an increase in water temperature. Fish quite successfully adapts after a month's stay in conditions of high water temperature to 31ºC, and the level of cortisol is reduced. The content of thyroid hormones in the blood of the rudd, roach and ruff is quite high and after a month of adaptation to the existing factors. This indicates an increased activity in their metabolic processes. The content of somatotropin and prolactin in the blood of the studied fish species decreases 2.4–5.0 and 1.9–7.7 times, respectively, in response to an increase in temperature and a decrease in the oxygen concentration in water. This should lead to a decrease in the rate of fish growth and change in the activity of osmotic exchange. However, hormonal reactions are species-specific in nature to the existing factors. Perch and roach are less plastic to increase water temperature. Carp most favorably tolerates an increase in water temperature and a decrease in oxygen concentration.

scholarly journals Factors affecting biochemical composition of seston in an eutrophic reservoir (Pampulha Reservoir, Belo Horizonte, MG

2000 ◽  
Vol 60 (1) ◽  
pp. 63-71 ◽  
Author(s):  
I. G. BOËCHAT ◽  
A. GIANI
Keyword(s):  
Seasonal Changes ◽  
Biochemical Composition ◽  
Abiotic Factors ◽  
Eutrophic Lake ◽  
Phytoplankton Assemblages ◽  
Factors Affecting ◽  
Physical Chemical ◽  
Algal Groups ◽  
Belo Horizonte ◽  
The Relationship

Sestonic biochemical composition (lipids, proteins and carbohydrates) may change with varying environmental fluctuations. These changes and the effects in the nutritional status of algae consists of an actual increasing source of interest. The aims of this work were to establish the relationship between biochemical composition of seston and 1) a range of physical, chemical and climatological factors, and 2) the natural fluctuation in the species composition in phytoplankton assemblages of the Pampulha Reservoir, an urban eutrophic lake located in Belo Horizonte, MG. Seasonal changes in the biochemical composition were observed in this study. None of the considered abiotic factors alone seem to affect the biochemical composition. So the effects could only be understood by interactions among different environmental factors. On the other hand, the dominant algal groups probably have some influence in the observed changes in biochemical composition of seston.

Effet de certains paramètres physico-chimiques sur les relations prédateurs–proies dans les populations de copépodes cyclopoïdes des mares temporaires d'eau douce

1986 ◽  
Vol 64 (1) ◽  
pp. 8-11
Author(s):  
Louise Vallières ◽  
Antoine Aubin
Keyword(s):  
Organic Matter ◽  
Body Size ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Feeding Ecology ◽  
Mineral Content ◽  
Abiotic Factors ◽  
Size Class ◽  
Regression Analyses ◽  
Physical And Chemical

Copepod populations of three temporary freshwater pools (Alnus unit, Carex unit, and Molinia unit) were studied using a standard approach (species versus abiotic factors) and a holistic one (body size and feeding ecology). Multiple regression analyses of data indicate that the physical and chemical features of water (temperature, pH, dissolved oxygen, mineral content, and depth) explain 62 to 98% of the variability of carnivorous copepods, while the abundance of their prey accounts for much less. No size class of prey seems to be preferred. The abundance of decaying organic matter, typical of such pools, would result in an overabundance of prey. Predators would then be under the control of nonalimentary factors.

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