Some effects of temperature on the growth and metabolic rate of juvenile blue crabs,Callinectes sapidus,in the laboratory

Juvenile blue crabs, Callinectes sapidus Rathbun, were grown in the laboratory at different temperatures, and metabolic-rate determinations were made. Growth is shown to be dependent upon temperature. Crabs kept at high temperatures (34° and 27°C) grow faster than those kept at lower temperatures (13°, 15°, and 20°C). Increase in size per molt is less at higher temperatures than at lower ones. Mortality is directly proportional to temperature between 13° and 34°C and is very high during ecdysis at elevated temperatures. Metabolic rate increases with temperature, but various degrees of acclimation are seen after 4 weeks exposure. No acclimation of general activity to temperature was found. The findings are applied theoretically to crabs living in the region of heated discharge canals of electrical generators: the motile blue crab could extend its growing season without decreasing size at maturity by active selection of thermal surroundings.In part based on a thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science at the University of Florida, USA.     

Effects of various temperature cycles on the larval development of the gastropod molluscCrepidula fornicata

Veligers ofCrepidula fornicata (L.) were reared for 12 days at constant temperatures of 15°, 20°, 25°, 30° and 35°C, and at 5 C° daily cycles of equal periodicity (COEP) over the temperature ranges 15° to 20°C, 20° to 25°C, 25° to 30°C and 30° to 35°C. COEP consisted of equal periods (6 h) of maximum temperature, minimum temperature, and uniformly increasing and decreasing temperature each 24 h period. Survival was high and not influenced by cyclic or constant temperature from 15° to 30°C. At 35°C and COEP 30° to 35°C, all larvae died before Day 6. Shell growth rate increased markedly over the range 15° to 25°C, and growth rates at cyclic temperatures in this range were intermediate between growth rates at the corresponding constant temperatures. Larvae reared at COEP 15° to 20°C and COEP 30° to 35°C had discontinuities in their shells due to inhibition of shell secretion during the adverse part of each temperature cycle. Groups ofc. fornicata veligers were exposed for 2 days to daily temperature cycles of equal and unequal periodicity in the critical 30° to 35°C range. [Cycles of unequal periodicity (COUP) consisted of unequal periods (varying between 3 and 15 h) of maximum and minimum temperature and uniformly increasing and decreasing temperature each 24 h period.] These veligers showed shell growth although their body tissue declined, as indicated by decreasing carbon content per larva. Least shell growth and most body tissue loss occurred in those cycles with the longest exposure to higher temperature. Larvae exposed for arious days to the mildest 30° to 35°C COUP (15 h at 30°C, 3 h increasing temperature, 3 h at 35°C and 3 h decreasing temperature) recovered and resumed normal growth when transferred to constant 30°C, but their growth was retarded in proportion to the number of days in the temperature cycle. Rates of shell growth of veligers in temperature cycles show an immediate effect of environmental temperature, while changes in carbon content per larva better reflect the effects of temperature on general metabolism and survival.     

Studies on differential fitness of PGI genotypes with regard to temperature in Gammarus insensibilis (Crustacea: Amphipoda)

This paper deals with an experimental study of survival, combined with estimates of biochemical activity, of different genotypes at the PGI (phosphoglucose isomerase) locus in Gammarus insensibilis, in relation to temperature. Samples were collected in the lagoon of Venice during 1987. No mortality occurred at 10°C whereas at 27°C, where mortality reached the value of 50%, heterozygotes exhibited significantly higher survival than homozygotes. Experiments conducted in order to evaluate the PGI biochemical activity of homo- and heterozygote genotypes at three different temperatures (4°, 20° and 37°C) showed in all genotypes an increased activity from 4° to 20°C and a fall of activity from 20° to 37°C. Heterozygotes exhibited higher activity at all temperatures tested. The difference between homo- and heterozygotes became more obvious at 37°C. Our results suggest that in G. insensibilis the PGI locus, as already shown in other organisms, may be subject to selection and that the heterozygous genotypes possess superior fitness. The biochemical bases of the observed differences between genotypes are briefly discussed.     

Effects of constant and cyclic temperatures on the salinity tolerance of the estuarine sandhopper Orchestia chiliensis

The survival of Orchestia chiliensis (Milne Edwards, 1840) was investigated at salinities between 0.3 and 68 and constant or 10 C° cyclic temperatures between 5° and 25° C. Mortality increased with age, temperature and at salinity extremes. Small individuals show little seasonal acclimatisation apart from increased thermal tolerance at the highest exposure temperature. Larger individuals show a lateral shift in the mortality curve to the right in summer, giving increased survival at most salinities. Salinity had less effect on amphipods in cyclic regimes and survival was similar in 5° to 15° C and 10° to 20° C cycles. Mortality of larger individuals was higher in the 15° to 25° C cycle, but seasonal acclimatisation gave increased resistance at all fluctuating temperatures during the summer. Mortality in cyclic temperatures was higher than at similar constant temperatures. O. chiliensis does not actively evade immersion and diel temperature changes of 10 C° represent an important stress factor. This would affect all life stages and influence field populations both in the winter and the summer.     

Temperature tolerance of the estuarine prawn Upogebia africana (Anomura,Crustacea)

Continuous temperature measurements were made in a typical South East African estuary. Mean summer (November to March) temperatures were in the range 19° to 24°C, and in winter (June to August) from 13° to 16°C. Large daily temperature fluctuations of 6° to 10°C occurred in summer; these appear to result from tidal movement of cool sea water into the estuary. In winter, temperature fluctuations were much smaller (3° to 5°C). The burrowing prawn Upogebia africana (Obtmann) was found to have an upper lethal temperature of 29°C in both winter and summer. The resistance time of prawns to temperatures above 30°C was much greater in summer than in winter. It was possible to acclimate winter prawns and increase their resistance time to a level comparable to that of summer individuals. A latent period of 40 h occurred before acclimation effects were detectable. Long-term exposure of prawns to high temperatures did not increase their resistance above that of summer prawns. Water at a temperature above this upper lethal temperature is not pumped through the burrows. This avoidance behaviour considerably increases the ability of U. africana to withstand short-lived temperature extremes.     

Latitudinal variation in the Dungeness crab,Cancer magister: zoeal morphology explained by incubation temperature

The difference in morphology between zoeae of Cancer magister Dana from Alaskan and Californian waters was documented to determine if the morphological variation is attributable to environmental influences. First-stage zoeae from Alaska have significantly longer carapace spines than zoeae from central California. The dorsal, rostral and lateral carapace spines were 14, 14 and 29% longer, respectively, in the Alaskan zoeae. The effect of temperature was tested on zoeal morphology as it is an obvious environmental difference between Alaskan and Californian waters. Ovigerous female crabs collected in southeastern Alaska in 1984 were held at 1°, 5°, 10° and 15° C until hatching occurred. Eggs were sampled seven times during the incubation period, and relative mortality, egg diameter and development stage were measured. All of the crabs and eggs at 1° C died before hatching occurred. Egg mortality averaged less than 2% in the other temperature treatments. Egg diameter increased significantly over the incubation period for all temperatures. Developmental rate of the embryos was inversely related to temperature. Hatching first occurred in 42 d at 15° C, 60 at 10° C and 160 d at 5° C. Newly hatched zoeae were collected and body length, dorsal, rostral and lateral carapace spines were measured. Significant differences existed between all temperatures for all spine lengths, with longer spines occurring at lower temperatures. Zoeal body lengths were also significantly different between the three temperatures. The results of this study question the use of spine lengths to distinguish similar larval species.     

Temperature-influenced infection rates in the Chondrus crispus—Petersenia pollagaster pathosystem: a regression analysis

Cross-infection experiments were performed to determine the influence of temperature on infection rate in the Chondrus crispus Stackhouse-Petersenia pollagaster (Petersen) Sparrow pathosystem. C. crispus thalli were collected at Pubnico Harbor, Nova Scotia, Canada in the fall of 1981 to 1984. Infective zoospores were used to inoculate healthy thalli at five different temperatures. The highest infection rate was obtained at 20°C, while significantly lower rates were obtained at temperature extremes. The parasite's life cycle, consisting of infection of healthy thalli, endobiotic development, and release of zoospores, was completed in 48 to 72 h at 15° to 20°C.     

Temperature adaptation in strains of the amphi-equatorial green alga Urospora penicilliformis (Acrosiphoniales): biogeographical implications

The temperature requirements for growth and the upper survival temperatures (UST's) of the amiphi-equatorial green alga Urospora penicilliformis collected from several localities within its distribution area between 1986 and 1991 were determined. Ecotypic variation, both with regard to growth ranges and optima and to survival temperatures, was demonstrated. In the polar strains of U. penicilliformis, temperature growth ranges were narrower and the growth optima and UST's were at lower temperatures compared to cold-temperate strains. In particular, the polar strains grew between 0 and 15°C with optimal growth at 0 or 5°C, whereas the cold-temperate isolates grew between 0 and (15) 20°C with almost equal growth rates or a growth optimum between 5 and 15°C. The Arctic strains survived 23 to 24°C, and the Antarctic isolate only 19°C, while the UST's of the cold-temperate isolates were between (24) 25 to 26°C. The data strongly indicate that a cold water history of ca. 3 million yr in the Arctic can be sufficient for changes in the temperature growth ranges and optima as well as for small changes of UST as shown in the Arctic populations of U. penicilliformis. For stronger reduction of upper survival temperatures, longer time periods are necessary as exemplified in the isolate from Antarctica, where low temperatures have existed for at least 14 million yr. The significantly lower UST of the Antarctic strain, points to an early contact of the alga with the cold water of the Antarctic region and may indicate an origin of U. penicilliformis in the Southern Hemisphere. The UST's of the cold-temperate isolates (24 to 26°C) would have allowed a migration across the equator during Pleistocene lowerings of the seawater temperatures in the tropics. Growth, however, would not have been possible during the passage across the equator due to the narrow temperature-growth window. The nature of the geographical boundaries and the control of seasonal development of U. penicilliformis by the temperature conditions in the various geographical regions are discussed in relation to the present local temperature regime.     

Incubation temperature has long-term effects on behaviour of young Pine snakes (Pituophis melanoleucus)

Summary Eggs of pine snakes (Pituophis melanoleucus) were incubated at constant temperatures of 21°, 23°, 26°, 28°, 30° and 32° C to determine behavioural differences as a function of incubation temperature. For all behavioural and physiological measures hatchlings from medium incubation temperatures (26°, 28°) performed tests better than those hatchlings from eggs incubated at low temperatures (21°, 23°). For some behavioural tests hatchlings from eggs incubated at high temperature (30°, 32°) performed less well than medium temperature hatchlings. These differences were not due to ambient temperatures or age of testing since these were held constant. Some of the behavioural differences persisted for 24 weeks.     

Metabolic adaptation of Cancer irroratus developmental stages to cyclic temperatures

Metabolic-temperature responses of the developmental stages of the sublittoral crab Cancer irroratus cultured at 10° to 20°C daily cyclic and 15°C constant temperatures were determined. Generally, the metabolic rate increased with temperature in the lower range with Q₁₀'s (temperature coefficients) above 2, compensated in the midrange with Q₁₀'s between 1 and 2, and declined at the higher temperatures with Q₁₀ values less than 1. For the larvae cultured at a constant temperature of 15°C, the compensatory response range narrowed with development from first zoeae to the later zoeal stages. In contrast, the compensatory response of the first zoeae, megalops, and crab stages within the range 10° to 25°C was interrupted by a zone of thermal sensitivity between 15° and 20°C for those individuals cultured in the 10° to 20°C cyclic regime. The compensatory response range is narrower for the third stage zoeae and broader for the second, fourth, and fifth stage zoeae. Metabolic rate-temperature (M-T) patterns of C. irroratus developmental stages cultured under the cyclic regime varied from those held at constant temperature by increased respiration and metabolic rate compensation between 20° and 25°C, and by an extension of the metabolically active range towards higher temperatures.     

Optimal growth and maximal survival temperatures of Atlantic Laminaria species (Phaeophyta) in culture

The effects of temperature on growth rate of rapidly-growing cultured macrosporophytes of 9 isolates of Atlantic Laminaria comprising 4 species have been investigated. No significant population variation was observed within species despite wide variations in temperature between the original collecting sites. L. saccharina showed a broad temperature optimum in the 10°–15°C range, whereas L. longicruris had a sharp optimum at 10°C. L. digitata and L. hyperborea grew more slowly, with only slightly sub-optimal growth over a wide temperature range, but with peaks at 10°C (L. digitata) and 15°C (L. hyperborea). The maximum survival temperatures of individual male and female vegetatively-growing gametophytes were ascertained for these species plus the Arctic L. solidungula, and were as follows: L. saccharina and L. longicruris, 23°C; L. digitata (male), 23°C; L. digitata (female), 22°C; L. hyperborea, 21°C; L. solidungula, 18°C. The lack of within-species differences demonstrates that the success of the genus in areas with different temperature regimes is brought about by phenotypic plasticity of individuals rather than the selection of temperature races or ecotypes.     

Effect of temperature on the escape responses of larval herring,Clupea harengus

Herring (Clupea harengus L.) larvae from spring and autumn spawning stocks were reared at different constant temperatures from 5° to 17 °C. At equivalent developmental stages, the spring larvae were longer than the autumn larvae and the larvae reared at low temperatures were longer than those reared at high temperatures. At hatching and at the end of the yolk-sac stage, the larvae were induced, by a probe, to make C-start escape responses, which were recorded and analysed using a high-speed video recording at 400 frames s^-1. The response was rapid and of short duration. The tailbeat frequency and swimming speed were measured during the burst of swimming following the C-start at different test temperatures and in larvae with different temperature histories. The tail-beat frequency was strongly temperature-dependent, rising from 19 Hz at 5 °C to 37 Hz at 17 °C with no effect of temperature history, season or developmental stage. The burst-swimming speed ranged at hatching from 75 to 90 mm s^-1 at 5 °C to 110 to 160 mm s^-1 at 17 °C and at yolk resorption from 90–115 mm s^-1 at 5 °C to 175–190 mm s^-1 at 17 °C. The longer, spring-spawned larvae swam faster than the shorter autumn-spawned larvae. When the swimming speeds were expressed as body lengths (L) s^-1, these differences disappeared. Larvae swam from 7–9 L s^-1 at 5 °C to 15–20 L s^-1 at 17 °C at hatching, and from 8–9 L s^-1 at 5 °C to 15–17 L s^-1 at 17 °C at yolk resorption. There was, however, a significantly faster specific swimming speed by the larvae reared at 12 °C in spring 1991.Honorary Research Fellow of the Scottish Association for Marine ScienceUnfortunately, Karen Fretwell was drowned in an accident on 9 January 1993     

Temperature ecotypes near the southern boundary of the kelp Laminaria saccharina

Effects of temperature on survival, growth, and photosynthesis were compared for two USA populations of Laminaria saccharina Lamour. One population was located in New York State, near the southern latitudinal boundary of the species in the western North Atlantic. This southern boundary population was exposed to ambient temperatures 20°C for about 6 wk each summer. The second population was located in Maine, toward the center of the latitudinal range of the species, and was rarely exposed to temperatures>17°C. sporophytes from the New York (NY) population exhibited greater tolerance of high temperature than plants from the Maine (ME) site. Juvenile sporophytes from the two sites had similar rates of survivorship and growth at temperatures below 20°C, but showed different responses at 20°C in laboratory experiments. NY plants survived and grew for 6 wk at 20°C. ME plants showed negative growth during wk 2 and 100% mortality during wk 3. NY and ME plants held in situ at the NY site during June to September, 1985, also exhibited differential survivorship when ambient temperatures exceeded 20°C. Results of photosynthesis and dark respiration measurements on NY and ME plants grown at various temperatures suggested that the high-temperature tolerance of NY plants was attributable to their ability to maintain positive daily net C-fixation at 20°C. The high-temperature tolerance of the NY plants appeared to be due to genetic adaptation and is probably crucial to the persistence of the species near its southern boundary.     

Autecological investigation on marine diatoms 3. Thalassiosira nordenskioeldii and Chaetoceros diadema

The temperature range for the best competitive position by growth of Thalassiosira nordenskioeldii Cleve has been determined by comparing generation times. It ranges from-1.5° to 6°C. At these temperatures, especially at lower light intensities, it was one of the fastest growing species, whereas above 6°C many other species grew faster. High light intensities at increasing temperatures became damaging. A flowering of the cold oligo-eurytherm diatom T. nordenskioeldii occurs not only in the upper layers, but can also occur at greater depth simultaneously, because decreasing daylengths at 6°C had the least influence on its growth. Continuous light at 6°C had a positive influence on its growth. The start of the T. nordenskioeldii spring flowering under the Arctic Sea Ice is discussed in connection with the occurrence of enclosed marine diatoms in Polar Sea Ice. The influence of the winter temperature on the spring flowering of the North Sea, the southern border for flowerings of T. nordenskioeldii, is discussed. For Chaetoceros diadema (Ehrenberg) Gran the best competitive position by growth is reached at-1.5° to about 6°C. It has the best opportunity of reaching high cell numbers at the lowest temperatures of the range. The occurrence of the cold oligo-eurytherm diatom Ch. diadema in plankton samples at temperatures above 10°C need not be incorret, for the species did grow in cultures at 12° and 16°C. The wrong interpretation of the experimentally determined optimum temperature of e.g. T. nordenskioeldii caused a discrepancy between experimental results and field data that does not exist. The question is discussed whether ecologically it is relevant to talk about a temperature optimum. On account of the results of T. nordenskioeldii the question of the adaptation of diatom cultures for the start of the real experiments is discussed.     

Incubation period for the lobster Homarus gammarus at various temperatures

For Homarus gammarus in the North Irish Sea, a notional spawning date of 15 August was selected on the basis of substantial commercial catch data. Berried females were exposed to fluctuating temperature regimes, with average temperatures between 10.0° and 18.3°C. Incubation periods ranged between 3.6 and 9.5 months. The relationship between incubation period and the sum of monthly average temperatures was approximately linear, and can be used to calculate the temperature regime required to cause hatching at a preselected time. At 10.4°C (the local annual average temperature), the estimated incubation period is 11 months. This is compared with data for H. americanus, which indicate an incubation period of 11.4 months at a local annual average temperature of about 8.1°C. The implications of this are discussed.     

Physiological ecology of four Polysiphonia species (Rhodophyta,Ceramiales)

Photosynthesis and respiration of 4 species of the marine red algal genus Polysiphonia were evaluated under a variety of light, temperature and salinity conditions. The manometric results were compared with the local distribution and abundance of each species. The species can be separated into two distinct categories based on their overall distribution and temperature optima: (1) cold water plants [P. lanosa (L.) Tandy and P. elongata (Hudson) Sprengel], with peak photosynthesis at 21° to 24°C, but with active photosynthesis as low as 5°C; (2) plants with warm-water affinities [P. nigrescens (Hudson) Greville and P. subtilissima Montagne], having photosynthetic optima at 27° to 30°C, and exhibiting little or no photosynthesis below 10°C. The plants from the first group exhibit thermal injury at temperatures of 25°C and show a narrow tolerance to low salinities during periods of high temperatures. The plants from the second group show thermal injury at 30°C and have a wider tolerance to low salinities. The horizontal distribution of the 4 Polysiphonia species within the Great Bay Estuary System of New Hampshire, USA, is primarily governed by their tolerances to high temperatures and low salinities. The temperature optimum for each of the species corresponds to its particular estuarine distribution. Thus, P. subtilissima, having the highest temperature optimum, penetrated furthest into the Estuary, while P. lanosa, having the lowest temperature optimum, was restricted to the more coastal stations. There was a good correspondence between the natural distribution patterns and the manometric results.Published with the approval of the Director of the New Hampshire Agricultural Experiment Station as Scientific Contribution No. 731.Scientific Contribution No. 4 of the Jackson Estuarine Laboratory.     

Influence of low temperature on the discharge mechanism of the electric fish Torpedo marmorata and T. ocellata

The influence of low temperature on the discharge of a part of the electric organ, evoked by electrical stimulation of the nerve leading to it, has been studied on in vitro nerve-electric tissue preparations of the fishes Torpedo marmorata or T. ocellata placed into sea water of different temperatures. It has been found that the amplitude of the discharge of the electric tissue made up from serially organized electroplaques sharply decreases at temperatures below 15 °C. The latent period of discharges increases most markedly at lower temperatures (about 10 °C). Experiments have been performed during July and August on fish caught in the Kotor bay of the Southern Adriatic. Questions related to the dissociation of different aspects of the intrinsic mechanism of the discharge generation by temperature, and to the possible significance of this finding with respect to the ecology of this fish, as well as possible adaptation mechanisms involved, are discussed.     

Yolk utilization and growth to yolk-sac absorption in summer flounder (Paralichthys dentatus) larvae at constant and cyclic temperatures

Rates of development, growth and yolk conversion efficiency were determined in larvae of the summer flounder Paralichtys dentatus at constant temperatures of 21°, 16°, 12° and 5°C and in temperature cycles of 21°–16°, 16°–11°, and 11°–5°C. In constant incubation temperatures, development rate increased with increasing temperature. Larvae reared in the cyclic temperature regimes exhibited development rates intermediate to those at the temperature extremes of the cycle. All larvae reared at 5°C and in the 11°–5°C cycle regime died prior to total yolk-sac absorption. Although development rates were temperature dependent, no significant differences in notochord length ash-free dry weight or yolk utilization efficiency were found at the time of total yolk-sac absorption. The similarity in growth and yolk utilization efficiency for larvae reared under these various temperature regimes suggests that the physiological mechanisms involved are able to compensate for temperature changes encountered in nature.Contribution No. 195 from EPA, Environmental Research Laboratory, Narragansett, Rhode Island 02882, USA     

Effect of temperature on the proliferation of Gymnodinium breve and Gomphosphaeria aponina

The effect of temperature on the growth and proliferation of two marine microorganisms, the toxigenic dinoflagellate Gymnodinium breve, and a potential bio-control organism, the blue-green alga Gomphosphaeria aponina, was determined by culturing the organisms in thermal gradients established by heating and cooling the opposite ends of an aluminum bar that had been adapted to hold culture tubes. Gradients were linear and stable for the duration of each trial. There was no relationship between variations in light and growth of the organisms. Gymnodinium breve showed optimum growth at 22°C, and proliferated over a range of temperatures (17° to 30°C). Below 17°C cultures of G. breve declined in growth, and at 4°C the organisms died within 5 h. Above 31°C there was rapid decline in viability of cells, and at 33.5°C the organism died within 24 h. Gomphosphaeria aponina showed optimum growth between 24° and 29°C, with a maximum at 27°C. Growth at temperatures greater than 31°C was minimal, but the organism survived. Limitation may be due to repression of the bio-synthesis of an iron-transport compound.     

Effect of temperature on nitrite excretion by three marine diatoms during nitrate uptake

Nitrite excretion during nitrate uptake by three nitrate-limited diatoms was measured at different temperatures. Phaeodactylum tricornutum Bohlin and Chaetoceros affinis Lauder Hustedt excreted nitrite over the whole range of physiological temperatures, whereas Thalassiosira pseudonana Hasle and Heimdal (Clone 13-1) excreted nitrite only at 25°C. Parallel to growth and nitrate-uptake rates, excretion rates increased exponentially with temperature, attaining a maximum between 20° and 25°C (optimum temperature range). At the end of nitrate uptake, when the nitrate concentration in the culture medium had decreased below 1 M, nitrite was reabsorbed at all temperatures, except when cells were in the dark or at very low light intensity. Nitrite uptake was also inhibited by the presence of nitrate in the medium. These results are discussed in relation to the formation and position of the maximum layer of primary nitrite in the thermocline, below the maximum layer of chlorophyll in stratified oceanic areas.