The Activity and Metabolism of Poikilothermal Animals in Different Latitudes.—I.

Abstract

Summary. This is the first comparative study of the activity and metabolism of poikilothermal animals living in different latitudes. For seven pairs of species of marine invertebrates, inhabiting respectively English waters and more northern seas, the oxygen consumption of the warmerwater species is greater than that of the colder‐water species (measured at the normal temperatures at which each species lives) although the locomotory activity of the former is apparently no greater (Table I., text‐figs. 1 & 2). It is suggested that the similar locomotory activities of the two species require approximately equal amounts of oxygen, but that the non‐locomotory oxygen consumption of the warm‐water species is higher than that of the cold‐water species. The rate of ciliary movement on the gill of the scallop Chlamys varia from English waters is higher than that of C. septemradiata from more northern waters, each measured at the temperatures at which the animals live (Table II., text‐fig. 3). The respiratory movements of English species of Crustacea are no more rapid than those of corresponding species in more northern waters (Table III., text‐fig. 4). The rate of heart‐beat has also been compared in species of Crustacea in English and more northern waters (Table III., text‐fig. 5). The rate of scaphognathite‐beat of the prawn Pandalus montagui is no more rapid in English than in more northern colder waters (Table III., text‐fig. 4). This is a case of variation within a single species in seas of different temperatures; it is parallel to what has been described above for pairs of different species inhabiting colder and warmer seas respectively.

On the behaviour of barnacles. IV: The influence of temperature On cirral activity and survival of some warm-water species

“…The rate of change with temperature was also different, and these other differences between the two forms, which were once regarded as varieties, are sufficient to justify separation as distinct species, a procedure already, suggested for morphological and ecological reasons (Utinomi, 1959). The lower rate of beat in C. depressus may perhaps be related to the rather precarious habitat it occupies, where a generally lower level of metabolic activity may be an advantage, or it may be a latitudinal effect (Fox, 1939), the metabolic rate being less at a given temperature in C. depressus than in the more northern form C. stellatus. The latter possibility would appear to be supported by the higher temperature at which optimum activity is reached in C. depressus and its reluctance to show rhythmic activity below 10°, but further comment must wait for more information on the distribution of the species.…”

On the behaviour of barnacles: I. The relation of cirral and other activities to temperature

“…A further part of the difference may well be an adaptation to colder or warmer temperatures than the animal experiences elsewhere in its distribution (cf. Fox, 1939), but until observations are made at other localities this cannot be determined.…”

Deep-sea hydrothermal vent animals seek cool fluids in a highly variable thermal environment

“…Many of the critical leaps in our understanding of how temperature regime shapes the thermal biology of ectotherms have been made by comparing the physiology and behaviours of animals along steep environmental gradients that represent extremes in thermal magnitude and variability over large (for example, latitudinal 8,9 and altitudinal gradients 10 ) and small spatial scales (for example, intertidal gradients 5,11 ). Hydrothermal vents create one of the most thermally variable habitats in which ectotherms live.…”