Seasonal Changes In Water Temperature Research Articles

Seasonal changes in fish abundance, biomass and species richness in the littoral zone of a large European lake, Lake Constance, Germany

Seasonal change- in the abundance. biornass and species richness of fixh in the littoral zone of Lake Coustancc were examined. Electric fishing was conducted in three depth strata at six different sampling sitc« within the littoral zone from Novem­ ber )991 to Fcbruar )993 during daytime. Minimal abundance and biomaxs values were observed in February with 3.9 (SO ± ..\..2) ind· lOO Ill- and 12.7 (SO ± LUI) g-wet· lOO III c. Maximal abundance value» were observed in August with 119.) (SO ± 88.)) ind· lOO m c. maximal hiom.i-,-, values in May with 9(n.9 (SO ± 1942.6) g-wet· 100 m c. The influence of indiv idual habitat variables on the littoral fish com­ munity was examined by canonical correlation analvxix. Seasonal chungcs in total fish abundance. biomass and species richuexx were muinl. explained by seasonal changes in water temperature followed by lake level. For the individual species. different sub­ xtratc characteristics such ~lS sediment type or the amount of large stones lying on the bottom providing shelter were also found to be important. However. these variables often influence fish abundance and biomas-, only within a range that is prcdcfincd by water temperature. Different patterns were found for the two bcnthic species. burbot iLota lota i and stone loaeh iNocnmchrilus burhatulusi. The distribution of both spe­ cies was mainly correlated with the availability of gravel substrate and shelter and mostly independent of littoral water temperature. Burhot larger than >5 cm TL cmi­ grated trom the littoral into deeper adjacent areas during summer when water temper­ ature increased above a certain threshold. indicating an upper thermal threshold for thi-, cold stenothermal species.

Short-term aquifer residence times estimated from 222Rn disequilibrium in artificially-recharged ground water

Radioactive disequilibrium of 222Rn permits age dating of very young ground water which has resided in the subsurface for up to 15 days. Inherent in this technique is the assumption that transported recharge flows through porous media with a relatively uniform 222Rn emanation rate. Changes in radon activity in response to rapid surface water infiltration from seasonally operated spreading basins were used to estimate subsurface residence times along ground water recharge flow paths. Radon activity was relatively constant in deep monitoring wells isolated from the immediate influence of surface recharge, suggesting that radon remained in secular equilibrium and deeper ground water residence times were in excess of the 15-day dating method limit. In contrast, radon activity in shallower ground water was highly variable during recharge and allowed estimation of ground water ages ranging from 4 to 14 days, using disequilibrium theory. Shorter residence times corresponded to wells most directly connected with the surface as indicated by seasonal changes in water temperature. Surface water recharge routes were confirmed in a related study with stable isotope fingerprinting, water level variations and agrichemical concentrations. Flow rates estimated from residence times ranged from 1.1 to 4.6 m day −1, and compare favourably with average subsurface velocities up to 4.5 m day −1 estimated from infiltration rates at the site. Residence time estimates using radon disequilibrium were in general agreement with bromide tracer breakthrough times determined in a related study. Differences between residence and breakthrough times indicate that changes in recharge flow routes, permeability and parent nuclide concentrations may produce erroneously high residence time estimates. Accumulation of fine sediment, eventually resulting in basin clogging, may increase parent isotope concentrations and radon emanation in the zone of infiltration.

Mean Seasonal Changes and Recent Trends of Dissolved Inorganic Nutrients in Okkirai Bay, Japan.

Mean seasonal changes in water temperature, salinity, silicate, phosphate, dissolved inorganic nitrogen, and dissolved oxygen (DO) in Okkirai Bay, Japan, were presented based on the monthly averaged data measured from 1979 to 1995. Recent trends of these properties were presented using 12-month running means. As a result, isopleths of mean seasonal changes showed a high nutrient concentration in winter and spring, and the vertical profile tended to be uniform. Recent trends showed great effects due to the Oyashio cold water that is rich in nutrients and DO, which came close to coastal waters in 1984, and that the water temperature has gradually increased since then, in line with decreasing nitrate, ammonium nitrogen, and DO.

Microbial food web in a large shallow lake (Lake Balaton, Hungary)

Seasonal variations of phyto-, bacterio- and colourless flagellate plankton were followed across a year in the large shallow Lake Balaton (Hungary). Yearly average chlorophyll-a concentration was 11 µg 1−1, while the corresponding values of bacterioplankton and heterotrophic nanoflagellate (HNF) plankton biomass (fresh weight) were 0.24 mg 1−1 and 0.35 mg 1−1, respectively. About half of planktonic primary production was channelled through bacterioplankton on the yearly basis. However, there was no significant correlation between phytoplankton biomass and bacterial abundance. Bacterial specific growth rates were in the range of 0.009 and 0.09 h−1, and ended to follow the seasonal changes in water temperature. In some periods of the year, predator-prey relationships between the HNF and bacterial abundance were obvious. The estimated HNF grazing on bacteria varied between 3% and 227% of the daily bacterial production. On an annual basis, 87% of bacterial cell production was grazed by HNF plankton.

Influence of seasonal changes in water temperature on cadmium inducibility of hepatic and renal metallothionein in rainbow trout

Changes in metallothionein (MT) levels in liver and kidney of juvenile rainbow trout ( Oncorhynchus mykiss) were followed for 8 months, as the water temperature was allowed to follow the natural temperature decrease in Tvären, a bay in the Baltic Sea. The temperature dropped from 15 °C to 2 °C during the experimental period. The liver and kidney were analysed for MT, zinc, copper and cadmium. Both the hepatic and renal MT levels were found to increase in the control group during the first 4 months of the experiment, as the water temperature dropped to 4 °C. Once the temperature had stabilized at 2 °C there was a noticeable decrease in both hepatic and renal MT levels. One group of fish was exposed to water-borne cadmium (100 μg Cd/litre) for the duration of the experiment. Cadmium accumulated in both liver and kidney, and reached the highest levels in the kidney. Exposure of the fish to cadmium resulted in marked elevations of kidney MT levels. In the liver the MT levels did not increase above the control levels as the temperature dropped to 2 °C after 6 months. However, once the temperature stabilized at 2 °C (after 8 months) the hepatic MT levels were significantly higher in cadmium-exposed fish than in the control fish.

Activity and feeding behaviour of Atlantic cod ( Gadus morhua) in sea pens

Behavioural observations were undertaken on Atlantic cod ( Gadus morhua) held in sea pens to determine food acceptance (proportion of food consumed) and activity levels of cod fed three different diets (capelin and two formulated feeds) and to determine how these behaviours were influenced by seasonal changes in water temperature. Results indicated that cod fed capelin had a significantly lower latency to handling feed, and rejected significantly fewer items than cod fed the formulated feeds. The capelin-fed cod also grew significantly more than those fed either formulated feed. The differences in growth appeared to be due to the proportion of each feed which the fish consumed, rather than any intrinsic qualities of the feeds. With declining temperature, activity levels decreased and feeding latency increased for fish from all three feed groups; however, food handling frequency and rejection rate increased for fish fed formulated feeds while remaining constant for fish fed capelin.

新潟市の開放型砂浜海岸浅海域におけるヨコエビ類Ａｍｐｅｌｉｓｃａ属の分布とその変動

The present study was carried out to examine changes in distribution of Ampelisca, an infaunal tube dweller at Igarashi Beach in Niigata prefecture on the Japan Sea during April 1992 to December 1993. The dominant Ampelisca at Igarashi Beach were A. naikaiensis and A. brevicornis. A. naikaiensis was found to be distributed in waters below 8m in depth, while A. brevicornis was found in waters between 6-30m in depth during summer to early autumn, and was found below depth 10m in early spring and early winter. There was no remarkable relationship between distribution range in Ampelisca and environmental factors i.e. seasonal changes in water temperature, salinity, and particle size and ignition loss of bottom material. Changes in distribution are well explained through relations to the seasonal frequency of days with strong winds (>8m/s, WSW-NE) which cause waves over 1m height, known to change the bottom topography in waters shallower than 12m depth in the open coast near Igarashi Beach. In this study, Ampelisca was found only at the stations where changes in bottom topography by high waves is expected to be minimal. These facts suggest that changes in bottom topography by high waves might prevent Ampelisca from building living tubes in open coast like Igarashi Beach.

Seasonal and temperature-induced changes in myosin heavy chain composition of crucian carp hearts.

Myosin heavy chain isoforms of the ventricular myocardium from crucian carp (Carassius carassius L.) hearts were analyzed in different times of the year by gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis [K. A. Esser, M. O. Boluyt, and T. P. White, Am. J. Physiol. 255 (Heart Circ. Physiol. 24): H659-H663, 1988]. In winter only one myosin heavy chain type was present, but in summer about one-half of the winter myosin was replaced by more slowly moving summer myosin. The occurrence of summer myosin correlated with seasonal changes in water temperature of the pond, where the fish were caught. Furthermore, the heavy chain composition of the heart was altered by temperature acclimation in the laboratory: cold-acclimated (2 degrees C) fish had only winter myosin, but warm-acclimated (22 degrees C) fish had both summer and winter myosin in about equal amounts. Myosin adenosinetriphosphatase activity of the hearts containing both summer and winter myosin was higher than that of hearts containing only winter myosin. Functionally, changes in myosin heavy chain composition were associated with inverse thermal acclimation in the heart rate. Warm-acclimated fish had higher in vitro heart rate and shorter contraction duration than cold-acclimated animals. Present findings suggest that changes in myosin heavy chain composition together with concomitant changes in Ca2+ activation of contraction make possible large seasonal alterations in the activity of crucian carp hearts. These adjustments are needed to adapt the cardiovascular system to winter hibernation and summer activity, which are dictated by seasonally bound changes in environmental conditions.

Effects of Seasonal Changes in Water Temperature on the Parr–Smolt Transformation of Atlantic Salmon and Anadromous Arctic Char

The effects of seasonal changes in water temperature on parr–smolt transformations of Atlantic salmon Salmo salar and anadromous Arctic char Salvelinus alpinus were compared by monitoring the degree of smolt coloration, hypo-osmoregulatory ability, and gill Na+,K+-ATPase activity. The fish were reared in continuous light. Atlantic salmon had typical parr characteristics in the winter and spring and typical smolt characteristics in the summer, showing marked body silvering, good seawater tolerance, and high gill Na+,K+-ATPase activity. The hypo-osmoregulatory ability was correlated with gill Na+,K+-ATPase activity. No similar seasonal variations in coloration, seawater tolerance, or gill Na+,K+-ATPase activity were recorded for Arctic char. The results indicate that an increase in water temperature may induce development of preparatory seawater tolerance in juveniles of Atlantic salmon, but not in juveniles of the anadromous Arctic char. These differences between Arctic char and Atlantic salmon in their responses to a rise in ambient temperature, a rise typical of late spring–early summer in coldwater areas, are discussed in relation to differences in the speciesˈ ecology.

Seasonal Changes in Water Temperature, pH, Dissolved Oxygen and Transparency in a Japanese High Mountain Lake, L. Mikuriga-ike.

Water temperature, pH, dissolved oxygen and transparency of a small Japanese high mountain lake, L. Mikuriga-ike, were measured from May to November 1974 -1978. The lake formed winter stratification until about the middle of July. Measurements in May and the middle of June showed that the water temperature from the surface to about 8 m deep was below 1°C, and that the water near the bottom was approximately anoxic with a slightly higher pH. Subsequently the lake water overturned at 2.5°C in the middle of July, and the circulation period continued to the end of July with the temperature rising to 4°C. Lake surface of the summer stratification had a temperature of over 15°C. In summer stratification, the water near the thermocline was supersaturated with oxygen. This study found that autumnal circulation began at the end of October (1974, 1976) or in the middle of November (1977) at about 5 or 6°C. The pH value of the lake water showed weak acidity between 5.2 and 6.6. Transparency changed from 1.0 m to 12.0 m in depth during the investigation.

Age and Growth of Nototodarus sloanii (Cephalopoda: Oegopsida) Based on Daily Increment Counts in Statoliths.

Statoliths of Nototodarus sloanii collected around New Zealand were examined to determine age. By comparing the increase in number of increments in statoliths with the number of days elapsed between sampling dates, the periodicity of the increment formation was validated. Estimated hatching month ranged from January to December. This result suggests that spawning occurs throughout the year. The relationship between statolith radius and dorsal mantle length suggests daily increment width must reflect squid growth well. Back-calculation was applied to compensate for the short sampling period. The differences in size at age are significant between the seasonal groups. The winter group is larger than the summer one between about 100 and 230 days old. This difference became smaller and finally the summer group became larger than the winter one at around 250 days old and after. It is suggested that differences in growth between the groups are consistent with seasonal changes in water temperature.

Temperature acclimation of respiration and photosynthesis in the brown algaLaminaria saccharina

Sporophytes of the brown algaLaminaria saccharina (L.) Lamour grown at 15°C contained significantly more chlorophylla (chla) than did similar plants grown at 5°C. The increase in chla in 15°C plants was due to increased numbers of photosystem II reaction centes, and possibly to increased photosynthetic unit size, compared with 5°C plants. These changes were associated with increasedα values (photosynthetic efficiencies) in 15°C-grownL. saccharina relative to 5°C-grown plants. The changes inα together with reduced respiration rates allowed 15°C-grownL. saccharina to achieve net photosynthesis and light-saturated photosynthesis at a lower photon fluence rate (PFR) than 5°C plants when both groups were assayed at the same temperature (15°C). The photon fluence rates necessary to reach the compensation point and achieve light-saturated photosynthesis (I c andI k , respectively) increased with increasing incubation temperature inL. saccharina grown at both 5 and 15°C. However, acclimation responses to growth temperature compensated for the short-term effect of temperature onI c andI k . Consequently, plants grown at 5 and 15°C were able to achieve similar rates of light-limited photosynthesis, and similarI c andI k values at their respective growth temperatures. These responses are undoubtedly important for perennial seaweeds such asL. saccharina, which frequently grow in light-limited habitats and experience pronounced seasonal changes in water temperature.

Bacterial secondary production and it relation with primary production in the Embalse del Río III Reservoir, Argentina

During an annual period the bacterial biomass (epifluorescence) and secondary production (methyl-3H-thymidine incorporation), as well as biomass (Chlorophyll) and algal primary production (incorporation of NaH14CO3) were studied in the Embalse del Rio III Reservoir, Argentina. The relations between these variables and their responses to seasonal changes in water temperature were analyzed. A close relationship in seasonal patterns of algal primary production and bacterial secondary production was observed, with the estimated rates of bacterial production similar to that obtained by other authors in eutrophic lakes. Bacterial production was 17 to 46% of the primary production, thus, at 60% assimilation efficiency, the bacterioplankton would consume 28 to 77 % of the total fixed carbon. Seasonal trends in algal primary production and bacterial secondary production were mainly affected by temperature.

Picoplanktonic algae in the northern Baltic Sea: seasonal dynamics and flagellate grazing

The seasonal succession of picoplanktonic algae was followed from March to December 1986 at a station off Tvarminne, northern Baltic Sea. This area is characterized by strong seasonal changes in water temperature and stratification Picoeukaryotes were abundant during the whole year (103 to 104 ml-'), but picocyanobacteria thrived only during summer (10' to 106 ml-'). The contrasting seasonal dynamics of these 2 groups led to the conclusion that growth of picocyanobacteria is more temperature dependent than that of the almost equally sized picoeukaryotes. However, the cyanobacterial dynamics could not be explained by temperature alone and light climatic changes may have contributed to the drastic decline of cyanobacterial numbers in the warm deep-mixed water column in the autumn. Estimates of flagellate grazing on picoplanktonic cyanobacteria were obtained by differential filtration experiments. These showed that flagellates could graze vigorously on picoalgae. Total flagellate grazing on picoalgae amounted to 15 % of annual primary production, and was estimated to be 32 and 42 % during summer and autumn, respectively. The microbial loop seems to be of major quantitative importance in the boreal northern Baltic Sea.

Correlation of stable oxygen isotope temperature record with light attenuation profiles in reef-dwellingTridacna shells

Molluscs are known to record environmental changes in their carbonate shells in detail. This paper reports the findings of a high-resolution analysis of stable oxygen isotopic compositions and light transmission properties of a shell of the reef-dwelling Pacific giant clamTridacna gigas. Our findings reveal that the annual growth rates and the longevity ofTridacna specimens can be readily determined by measuring the annual light attenuation pattern within the shell. Annual seasonal changes in water temperature are reflected with high resolution in the stable oxygen isotope ratios and in the light attenuation values of the aragonite shell. The inner shell ofT. gigas deposited below the pallial line revealing undisturbed shell accretion with high growth rates shows the maximum seasonal oxygen isotope range and the highest resolution in light attenuation changes. We suggest that this is the best part of the shell to reconstruct former seasonal surface water temperatures in tropical environments. Scanning electron microscopy (SEM) studies suggest that the annual growth patterns observed in transmitted light are generated by a complex pattern of daily growth increments with varying sizes of skeletal crystallites and varying amounts of organic carbon.

New ecological information onScytalina cerdale (Pisces: Scytalinidae) from a central California rocky intertidal zone

New information regarding the ecology ofScytalina cerdale was obtained over a four year period as a consequence of a long-term marine ecological study at the Diablo Canyon Power Plant (DCPP), San Luis Obispo County, California. Twenty intertidal fish surveys were conducted at approximately quarterly intervals, between March 1979 and June 1983, at three separate rocky shore locations (stations). During each survey, a total of 108 square meters (36 m2 per station) was searched for fish during periods of low tide. A total of 280S. cerdale were collected, identified, measured, and released back into the same 4 m2 area, from the same intertidal station (Diablo Cove), throughout the study period. This limited intertidal occurrence most likely reflectsS. cerdale microhabitat requirements; a combination of intertidal elevation (mean = +0.3 MLLW), substratum specificity (loose gravel, 5–10mm size range, overlying a base of sand and shell fragments), and degree of wave exposure (semi-protected). Throughout the study,S. cerdale was seasonally more abundant during summer months (June through August) and less abundant during winter months (November through February). The only exception to this abundance trend followed the 1982 winter storms, which coincided with an El Nino event, whenS. cerdale abundance uncharacteristically dropped during the subsequent 1983 spring and summer surveys. Mean total lengths did not vary greatly, reflecting the absence of early juvenile fishes, and relatively high mean fish densities (3.5 fish per m2 for 20 surveys) were recorded. Qualitative comparisons betweenS. cerdale abundance and seasonal changes in water temperature indicated an inverse relationship. Gravid females, demersal egg masses, and early juvenile individuals were never observed during the four years of the study. This suggests that unlike most other intertidal fishes, particularly other blennioids,S. cerdale may not utilize the intertidal zone for reproductive and recruitment purposes; Diablo Canyon is the most southerly reported distribution for this intertidal species, and therefore, may not entirely represent the species' biology as a whole.

Movement and Habitat Use by Stream-Dwelling Smallmouth Bass

We monitored the movement and habitat use of 34 stream-dwelling smallmouth bass Micropterus dolomieui in Jacks Fork River, Missouri, by radiotelemetry. Observations were made 24 h/d in all seasons. Definite patterns of diel activity and habitat use were evident and were modified by seasonal changes in water temperature. Fish remained in restricted home ranges for most of the year but tended to disperse in spring when all of the radio-tagged fish left their home pool; 75% returned during the same season. Equal numbers of fish moved upstream and downstream. However, the median distance moved upstream was greater. Intrapool movement of smallmouth bass peaked soon after sunrise and again after sunset in all seasons. Average intrapool movement was 120 m/d when water temperatures were lowest (4°C) and 980 m/d when temperatures were highest (27.5°C). In the warmer seasons, fish preferred logjams and root wads by day and increased their use of boulders at night. In cooler seasons, fish used boulders almost exclusively. Regardless of season, open water without cover was used most during the period just after sunrise but was never used in proportion to its availability. Boulders were the most preferred substrate, and gravel was the least preferred. Small mouth bass used intermediate depths the most and showed no daily or seasonal changes in depth preferences. Fish preferred velocities less than 0.2 m/s at all times of day and in all seasons. Movements in floods did not differ from those observed during normal discharges; however, single logs were selected in significantly greater proportion than logjams.

Temperature acclimation in culturedEucheuma isiforme from Florida andE. alvarezii from the Philippines

Branch cultures ofEucheuma alvarezii Doty var.tambalang Doty, farmed in the Philippines, andE. isiforme (C. Agardh) J. Agardh var.denudatum Cheney, from the west coast of Florida, were gradually transferred through three temperature regimes over a 6-week period. Photosynthetic responses were measured under a series of irradiances (P-I curves) and temperatures to determine immediate responses of the plants before, during and after completion of the transfers. The Philippine variety did not show acclimation to 18 °C either after gradual transfer from the initial culture temperature of 25 °C or when abruptly transferred from 25 to 18 °C. The Florida variety did show acclimation to 25 °C when gradually transferred from 18 to 22 to 25 °C over the 6-week period, but not if abruptly transferred from 18 to 25 °C. The west coast variety ofE. isiforme from Florida shows a temperature acclimation ability that parallels the seasonal changes in water temperature of its habitat.

Hematological assessment of temperature and oxygen stress in a reservoir population of striped bass ( Morone saxatilis)

1. 1. Hematological characteristics of a reservoir population of adult striped bass were monitored for 15 months to evaluate their responses to seasonal changes in water temperature and dissolved oxygen concentration. All fish were caught and removed from gill nets within 1 hr. 2. 2. All hematological parameters measured varied significantly with month of capture. In general, red blood cell counts, hematocrits, hemoglobin concentrations, and mean corpuscular hemoglobin values were highest in autumn and winter and lowest in summer. 3. 3. Most hematological parameters measured were significantly correlated with both water temperature and dissolved oxygen concentration at the site of capture. 4. 4. The hematological changes observed in this study suggest that fish were stressed by high water temperatures and low concentrations of dissolved oxygen in summer 1987, and that this stress probably resulted in secondary nutritional problems and extensive mortality.

Experimental analysis of predation on the diel vertical migrations of a larval salamander

The effects of a predatory fish on diel vertical migrations of aquatic larvae of the salamander Ambystoma talpoideum were tested in artificial ponds. Associations between larval activity and water temperature and resource abundance were also examined. In the absence of fish, larval activity was associated with the onset of darkness and decreasing water temperature. Peak larval activity occurred at 2130, about 3.5 h after peak summer water temperatures. Resource abundance (zooplankton density) in the water column did not differ from day to night. Larvae were more active during the day in spring than in summer. The presence of a visually orienting fish predator restricted larval activity to the benthic layer. Our results suggest that the presence of a visually orienting predator can be a major factor affecting patterns of diel vertical migrations. Daily and seasonal changes in water temperatures may affect thermoregulatory behavior, thereby influencing diel vertical migration patterns.