Changes In Water Salinity Research Articles

Effects of temperature and salinity on diatom cell lysis by DNA and RNA viruses

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 79:79-83 (2017) - DOI: https://doi.org/10.3354/ame01818 NOTE Effects of temperature and salinity on diatom cell lysis by DNA and RNA viruses Kei Kimura1,**, Yuji Tomaru2,*,** 1Institute of Lowland and Marine Research, Saga University, Honjo-machi 1, Saga 840-8502, Japan 2National Research Institute of Fisheries and Environment of Inland Sea, Japan Fisheries Research and Education Agency, 2-17-5 Maruishi, Hatsukaichi, Hiroshima 739-0452, Japan *Corresponding author: tomaruy@affrc.go.jp**The authors contributed equally to this work ABSTRACT: In estuarine and coastal environments, microbes are exposed to significant changes in the environment within short time periods. To examine the effects of water temperature and salinity on host-virus interactions, we used 2 strains of the marine planktonic diatom Chaetoceros tenuissimus and 4 viruses that exhibit contrasting host specificities. We found that the time necessary for a given virus to lyse half the diatoms within a culture (CR50), measured as the number of days required for chlorophyll a fluorescence intensity of host cells to decrease by >50%, was significantly affected by changes in both water temperature and salinity. In several host-virus combinations, environmental suitability for the growth of the host and the CR50 of the virus were significantly correlated, but no correlation was observed for other combinations. The CR50 values for different viral strains varied significantly depending on the combination of temperature and salinity tested. Moreover, optimum conditions for host cell lysis were highly diverse among virus species and isolates. The varied environmental optima of viruses might allow them to partition use of the same host species in natural environments. KEY WORDS: Water temperature · Water salinity · Host-virus interactions · Diatom lysis Full text in pdf format Supplementary material PreviousCite this article as: Kimura K, Tomaru Y (2017) Effects of temperature and salinity on diatom cell lysis by DNA and RNA viruses. Aquat Microb Ecol 79:79-83. https://doi.org/10.3354/ame01818 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 79, No. 1. Online publication date: April 13, 2017 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2017 Inter-Research.

Analysis of Possible Actions to Manage the Longitudinal Changes of Water Salinity in a Tidal River

In previous studies we have ascertained that inflows and seawater intrusion in the Shatt al-Arab River (SAR) are two key physical factors behind fluctuating and sharply escalating salinities observed in recent years. Such levels require a series of countermeasures and investigative studies to translate physical factors into a salinity dynamics model to understand the problem and its impact as these factors vary in location, time and quantity. A one-dimensional hydrodynamic and salt intrusion numerical model was applied to simulate the complex salinity regime in the SAR based on hourly time-series data for the year 2014. The model was used to analyse the impact of different management scenarios on salinity under different conditions. The results show a high correlation between seawater intrusion and river discharge. Increased use of water upstream and local water withdrawals along the SAR will increase seawater intrusion and salinity concentrations. Improving the quantity and quality of the upstream freshwater sources could reduce salinity levels. Discharging the drainage water into the river could be used to counteract the salt intrusion, considering that its location affects both the salinity distribution and extent. A scenario analysis based on a numerical model constructed for the longitudinal salinity variation associated with different sources in a tidal regime, can efficiently screen alternative water management strategies.

Iron oxide reduction in methane-rich deep Baltic Sea sediments

Methane is a powerful greenhouse gas and its emission from marine sediments to the atmosphere is largely controlled by anaerobic oxidation of methane (AOM). Traditionally, sulfate is considered to be the most important electron acceptor for AOM in marine sediments. Recent evidence suggests, however, that AOM may also be coupled to the reduction of iron (Fe) oxides. In the Baltic Sea, the post-glacial transition from the Ancylus freshwater phase to the Littorina brackish/marine phase (A/L-transition) around 9–7kyrBP (before present), resulted in the accumulation of organic-rich brackish/marine sediments overlying organic-poor limnic deposits rich in Fe oxides. Methane produced in the organic-rich layer diffuses into the lake sediments, thus allowing for the possible coupling between Fe oxide reduction and methane oxidation.Here, we combine detailed geochemical analyses of the sediment and pore water retrieved from three sites that were drilled during the IODP Baltic Sea Paleoenvironment Expedition 347 with multicomponent diagenetic modeling to study the possible role of Fe-mediated AOM as a mechanism for the apparent Fe oxide reduction in the methane-bearing lake deposits below the A/L transition. Our results reveal a complex interplay between production, oxidation and transport of methane showing that besides organoclastic Fe reduction, oxidation of downward migrating methane with Fe oxides may also explain the elevated concentrations of dissolved ferrous Fe in deep Baltic Sea sediments. Our findings imply that the transition of a lake toward a marine system could lead to reactivation of deeply buried, mostly crystalline Fe oxides in organic-poor lake deposits through reactions with downward diffusing methane from the overlying organic-rich marine sediments. Based on the geochemical profiles and numerical modeling, we propose that a potential coupling between Fe oxide reduction and methane oxidation likely affects deep Fe cycling and related biogeochemical processes, such as burial of phosphorus, in systems subject to changes in organic matter loading or bottom water salinity.

Changes in wintertime pH and hydrography of the Gulf of Finland (Baltic Sea) with focus on depth layers.

We studied changes in sea water pH, temperature and salinity with focus on two depth layers, along the Gulf of Finland (the Baltic Sea) using long-term monitoring data from 1979 to 2015. Data from the most frequently sampled monitoring stations between western and eastern Gulf of Finland were used. The main result of the study reveals that pH has decreased both in surface and deep-water in the western Gulf of Finland with values ranging between -0.005 and -0.008unitsyear-1. We also demonstrate a rise in temperature (~2°C) and decrease in salinity (~-0.7gkg-1) at several stations over the last 36years. In general, the changes are shown to be more pronounced in the western part of the gulf. This paper also stresses the importance of improving the sampling frequency and quality of monitoring measurements.

Partial desalination of hypersaline brine by lab-scale ion concentration polarization device

In this paper, technical and economic feasibility of partial desalination of hypersaline brine by ion concentration polarization (ICP) desalination is examined. We engineered a lab-scale ICP desalination system producing flow rate up to 96mL/min, which represents the largest scale-up of ICP desalination process so far. With highly saline brine feed water (NaCl, 70,000mg/L of TDS) and utilizing two different cation exchange membranes, we measured electrical responses of unit fluidic cell, and monitored the product water salinity changes over a wide ranges of flow velocities and electric current densities. Based on these, realistic power consumption and expected cost of brine treatment can be calculated, for the economic validation of partial brine desalination by ICP process. For the salt removal ratio of 50%, the optimal water cost is obtained as $3.08/m3 while the least power consumption is achieved as 5.6kWh/m3. Our results also show that the partial desalination could be more economically preferable than complete desalination for the brine management. Yet, ICP desalination should be further improved and optimized, with significant potential to be applied in many different desalination applications and hybrid scenarios.

Spit Migration Evolution across the Estuary of Rosetta Branch of the Nile River in Egypt

Coastal geomorphology changes are commonly experienced phenomena. Its study is important for the overall and sustainable strategy for integrated coastal zone management and forecasting of the future coastal changes. Impacts such as these not only affect the estuarine ecology, they also impact on the stability of the shoreline, water salinity change, social and economic value of estuaries. Spits are very dynamic coastal features steered by complex formation and evolution processes. Rosetta Estuary spit is observed with spatial and temporal changes. Spit situation has been compared with its historical information to check the variation using satellite images and field visit. Mechanical analysis of Rosetta Estuary sediments was executed to confirm that the surface sediments of the last part of Rosetta Estuary were originally from the coastal area. has been carried out. Moreover, salinity has been measured at different location of the study area. Migration of the spit was recognized towards the riverside. The detected migration was 1.5 km during the period from 2007 to 2015 with rate about 187 m/y. The factors that affect the formation of the spit inside Rosetta Estuary were listed and discussed.

Effects of sublethal salinity and temperature levels and their interaction on growth performance and hematological and hormonal levels in tra catfish (Pangasianodon hypophthalmus)

Climate change predictions suggest that the aquatic environment in the Mekong River Delta will change significantly over the next several decades, primarily manifested as higher temperatures with extensive marine incursions. As such, this study was conducted to evaluate the effects of sublethal levels of temperature and salinity and their interaction (TxS) on growth rates and physiological responses of tra catfish (Pangasianodon hypophthalmus), a significant culture species in Vietnam. We aimed to assess the levels of tolerance and acclimation ability when individuals were exposed to simulated predicted conditions of climate change on fish farms in the Mekong Delta in southern Vietnam. Fish were acclimated over an appropriate time frame and then distributed randomly to nine treatment groups across combinations of three temperatures (25, 30, 35 °C) and three salinities (0, 6, 12‰). Results showed that temperature, salinity, and TxS all had significant effects on individual growth rate and feed conversion efficiency, with fish reared at 35 °C and 6‰ salinity displaying the best growth (P < 0.05), while also producing significantly superior FCR values in comparison with the majority of other treatments. Tra catfish were able to acclimate to changes in water temperature and salinity, by increasing their RBC and Hb concentrations. Internal osmotic pressure was salinity-dependent with significantly higher pressure seen when fish were exposed to 12‰ conditions when compared with other treatments, irrespective of temperature. Interaction effects among temperature, salinity, and sampling time were identified for plasma glucose concentration, cortisol, and IGF-1 levels. Glucose, cortisol, and IGF-1 levels increased over the early phase of the experiment, then declined and stabilized for the remainder of the experiment. These results together suggest that moderate increases in water temperature and salinity do not impose a significant stress the tra used in this experiment. Therefore, it appears that the tra catfish industry is unlikely to suffer short-term negative impacts under predicted climate change scenarios, and performance may actually improve in conditions of 35 °C-6‰.

Microfacies, foraminifers and carbon and oxygen isotopes in a basinal section of the Zechstein Limestone (Wuchiapingian): Bonikowo 2 borehole, western Poland

The Zechstein Limestone of the Bonikowo 2 borehole is composed of limestone with varied dolomite content and is slightly thicker (3.4 m) than other supposed condensed sections in SW Poland. The microfacies (mostly bioclastic wackestones-packstones) are characteristic of open marine limestone deposited in deep shelf environments. The common occurrence of echinoids in all parts of the section, except close to its top, indicates no essential change in sea water salinity. However, the palaeotemperature interpretation of the highest δ 18 O value of calcite recorded in the Bonikowo 2 borehole (+0.32‰) indicates a temperature of 22.9°C when a δ 18 O of water = 2‰ is assumed. The δ 13 C and δ 18 O curves for calcite and dolomite are similar in shape, and their mean values are similar: +1.8 ±1.5‰ for calcite, respectively, and +1.9 ±2.3‰ and –4.3 ±2.4‰, –3.8 ±4.3‰ for dolomite. There is a recrystallized interval in the lower part of the section with both δ 13 C and δ 18 O values reduced. This may be regarded as an aerobic equivalent of the Kupferschiefer. The diversity and abundance of foraminifers is significant throughout the section studied; lagenids prevail, and this is considered to be due to the dysaerobic conditions throughout the duration of deposition of the Zechstein Limestone

Serum cortisol concentrations change in tiger grouper, Epinephelus fuscoguttatus in response to water temperature and salinity stress

The present exposition was designed to evaluate blood serum changes in tiger grouper, Epinephelus fuscoguttatus in response to changes in water temperature and salinity. Uniformly sized fingerlings were randomly distributed into different groups at fifteen fish per tank, in two replicates. Each group represented experimental fishes subjected to water temperatures of 18, 24, 28 and 30°C (control), and salinity of 10, 20 and 30 (control) ppt respectively. Replicate groups of fishes in each tank were exposed to these physiological stressors for 4 and 36 hours. At the end of experiment, blood samples were collected via caudal vein. The collected blood was centrifuged to obtain serum, andanalyzed for cortisol and glucose concentrations, using ELISA method. Results showed that decrease (to 28, 24 and 18°C) in water temperature from the control (30°C) and salinity from 30 ppt to 20 and 10 ppt for 4 and 36 hours influenced changes in the physical appearances (skin coloration) and behaviors (swimming vigor, opercula movement and schooling) of fish, to suggest responses to stress. Further, analyses of serum cortisol revealed consistently higher concentrations at the lower temperatures tested (to 28, 24 and 18°C), than the optimum tolerated by the species. Interestingly, fish maintained at 28°C for 36 hours contained lower serum cortisol concentrations compared to control groups. Meanwhile, the increment of the serum cortisol concentration occurs at decreased water salinity from 30 ppt to 20 and 10 ppt for 4 and 36 hours. It is concluded that: 1) water temperature and salinity are important physiological stressors; 2) sudden alteration of these factors leads to stress, and should therefore be avoided or minimized; 3) results of the present trial suggest that the blood serum factors are reliable parameters for evaluating the level of stress in fish.

Sedimentary alkenone distributions reflect salinity changes in the Baltic Sea over the Holocene

The Baltic Sea has had a complex salinity history since the last deglaciation. Here we show how distributions of alkenones and their δD values varied with past fluctuations in salinity in the Baltic Sea over the Holocene by examining a Holocene record (11.2–0.1cal kyr BP) from the Arkona Basin. Major changes in the alkenone distribution, i.e., changes in the fractional abundance of the C37:4 Me alkenone, the C38:2 Et alkenone and a C36:2 Me alkenone, the latter which has not been reported in the Baltic Sea previously, correlated with known changes in salinity. Both alkenone distributions and hydrogen isotopic composition suggest a shift in haptophyte species composition from lacustrine to brackish type haptophytes around 7.7–7.2cal kyr BP, corresponding with a salinity change that occurred when the connection between the basin and the North Sea was re-established. A similar salinity change occurred in the Black Sea. Previously published alkenone distributions and their δD values from the Black Sea were used to reconstruct Holocene changes in surface water salinity and, hence, it was shown that the unusual C36:2 alkenone dominates the alkenone distribution at salinities of 2–8ppt (g/kg). This information was used to corroborate the interpretations made about salinity changes from the data presented for the Baltic Sea. Low and variable salinity waters in the Baltic Sea over the Holocene have led to a variable alkenone-producing haptophyte community composition, including low salinity adapted species, hindering the use of the unsaturation ratios of long-chain alkenones for sea surface temperature reconstruction. However, these alkenone based indices are potentially useful for studying variations in salinity, regionally as well as in the past.

Evaluation of water salinity effects on the sea lice Lepeophtheirus salmonis found on farmed Atlantic salmon in Muchalat Inlet, British Columbia, Canada

The sea louse Lepeophtheirus salmonis is a major ectoparasite of both farmed and wild salmonids that causes substantial economic losses to the salmon industry worldwide. However, in British Columbia (BC) sea lice do not typically represent a significant health threat to farmed salmon. Sea lice patterns on Atlantic salmon farms in BC are not fully understood, but it is believed they are highly influenced by sea water salinity levels, which vary dramatically over the year. The objective of this investigation was to evaluate the effects of changes in water salinity on mobile L. salmonis found in farmed salmonids in the Muchalat Inlet, BC, while controlling for potential confounding factors. Using daily farm-based salinity measurements over a 13-year period, we built different salinity metrics to summarize salinity drops within specific periods of time prior to sea lice sampling events. Our results suggest that reduced salinity negatively impacted mobile sea lice in three different ways: first, a direct effect on mobile lice, lasting nomore than one day; second, an effect mediated by detrimental impacts on pre-mobile lice stages; and third, an effect possibly associated with reduced fecundity of parents of that lice cohort. These findings confirm the important role of salinity on sea lice population dynamics in BC, and contribute new knowledge which is useful in understanding sea lice patterns and determinants in this region. Relevance statementWe provided evidence that salinity can naturally control sea lice in British Columbia.

Feeding ω-3 PUFA enriched rotifers to Galaxias maculatus (Jenyns, 1842) larvae reared at different salinity conditions: effects on growth parameters, survival and fatty acids profile

Despite the well known importance of ω-3 polyunsaturated fatty acids (PUFA) in marine and freshwater fish larvae, there are few studies on how essential fatty acid requirements and composition on whole body can be altered by changes in water salinity. The present study aimed to determine the effect of salinity on ω-3 PUFA requirements, larval growth survival and fatty acid composition of G. maculatus larvae cultured at two different salinities (0 and 15 g∙L-1) for 20 days while fed rotifers containing two different levels of ω-3 PUFA (1.87 and 3.16%). The results denoted a marked difference in ω-3 PUFA requirements and in the pattern of fatty acid deposition in the whole body of larvae reared at different salinities, depending of ω-3 PUFA in diets. Thus, to improve growth and survival larvae of G. maculatus reared at 0 g∙L-1 require higher levels of ω-3 PUFA, principally 18: 3ω-3. Larvae reared at salinities of 15 g∙L-1 require low levels of ω-3 PUFA for optimal survival, especially 18: 3ω-3. Eicosapentaenoic acid and docosahexaenoic acid content in the whole body of larvae was also affected by water salinity.

Ostreopsis cf. ovata from western Mediterranean Sea: Physiological responses under different temperature and salinity conditions

The dinoflagellate Ostreopsis cf. ovata proliferates seasonally in the Mediterranean Sea, producing palytoxin-like compounds (ovatoxins) which are considered among the most potent marine toxins. Blooms have been related to several toxic events in which respiratory problems in humans and mortality of benthic marine organisms have been observed. In the coming decades, an increase in temperature and salinity is predicted in the Mediterranean Sea as a consequence of global warming that may provoke alterations in the dynamics of marine microorganisms. In this study, the physiological effects of changes in water temperature and salinity were analyzed, and their interaction through a multi-factorial experiment using two strains of O. cf. ovata in culture that had been isolated from the western Mediterranean Sea. In order to perform an accurate and reliable estimation of cell abundance, hydrochloric acid and sodium-ethylenediaminetetraacetic acid treatments were evaluated for the purpose of disaggregating cell clumps, with the former providing lower counting errors, especially after the stationary phase. Results of the physiological study showed that growth was inhibited at 19°C for all salinities. The highest growth rates were registered at 24°C for both strains (0.48±0.05divday−1), and a significant variability in growth rate was found among salinities at 24°C and 28°C. Two groups were distinguished by cell size in all high temperature conditions and a positive correlation was found between the amount of small cells and growth rate. The concentration of palytoxin-like compounds in the cultures increased with time and significantly higher amounts of toxin were found at 28°C in comparison to 24°C. The results suggest that climate change may not affect intensity of blooms, but their toxicity may be enhanced.

Rhizophoraceae Mangrove Saplings Use Hypocotyl and Leaf Water Storage Capacity to Cope with Soil Water Salinity Changes.

Some of the most striking features of Rhizophoraceae mangrove saplings are their voluminous cylinder-shaped hypocotyls and thickened leaves. The hypocotyls are known to serve as floats during seed dispersal (hydrochory) and store nutrients that allow the seedling to root and settle. In this study we investigate to what degree the hypocotyls and leaves can serve as water reservoirs once seedlings have settled, helping the plant to buffer the rapid water potential changes that are typical for the mangrove environment. We exposed saplings of two Rhizophoraceae species to three levels of salinity (15, 30, and 0–5‰, in that sequence) while non-invasively monitoring changes in hypocotyl and leaf water content by means of mobile NMR sensors. As a proxy for water content, changes in hypocotyl diameter and leaf thickness were monitored by means of dendrometers. Hypocotyl diameter variations were also monitored in the field on a Rhizophora species. The saplings were able to buffer rapid rhizosphere salinity changes using water stored in hypocotyls and leaves, but the largest water storage capacity was found in the leaves. We conclude that in Rhizophora and Bruguiera the hypocotyl offers the bulk of water buffering capacity during the dispersal phase and directly after settlement when only few leaves are present. As saplings develop more leaves, the significance of the leaves as a water storage organ becomes larger than that of the hypocotyl.

Sedimentological and paleoenvironmental scenario before, during, and after the Messinian Salinity Crisis: The San Miguel de Salinas composite section (western Mediterranean)

A composite stratigraphic section ranging from the Messinian to the Pliocene, recording the most important phases of the Messinian Salinity Crisis, is represented in the San Miguel de Salinas area (Bajo Segura basin, SE Spain). Detailed magnetostratigraphic and facies analyses and foraminifer and nannoplankton assemblage studies were carried out. Integration of the results has allowed the characterization of the pre-evaporitic (synthem Messinian I), syn-evaporitic (synthem Messinian II), and post-evaporitic phases (synthem Pliocene) from a paleoenvironmental and chronostratigraphic standpoint. The pre-evaporitic phase is late Messinian and records a shallowing-upward trend. The syn-evaporitic phase took place in chron C3r and is characterized by laminated marls with intercalated selenitic gypsum beds and sandstones. Variations in foraminifer and nannoplankton assemblages together with episodic gypsum precipitation record major changes in water salinity in a stressed marine environment. The pre- and syn-evaporitic phases are separated by the intra-Messinian unconformity, represented by an erosional surface related with a sea-level fall. After the evaporitic phase, a sea-level fall generates the end-Messinian unconformity, whose strongly erosional nature is evidenced by the deeply carved paleovalley of San Miguel de Salinas. The post-evaporitic phase begins in the earliest Pliocene and records the re-establishment of normal marine conditions in the basin. Since the San Miguel de Salinas composite section can be considered as a benchmark for the study of the evolution of marginal Mediterranean basins during the Messinian Salinity Crisis, the detailed characterization of these different phases is of great importance in understanding this event.

Response of the carpet shell clam (Ruditapes decussatus) and the Manila clam (Ruditapes philippinarum) to salinity stress

AbstractEnvironmental stressors are known to play an important role in determining the distribution and abundance of intertidal species. Marine molluscs are particularly susceptible to changes in water temperature and salinity in inter-tidal zones.

Diatoms and aquatic palynomorphs in surface sediments of the White Sea bays as indicators of sedimentation in marginal filters of rivers

Diatom algae, aquatic palynomorphs, and the grain-size of surface sediments from bays of the White Sea were investigated in a program dedicated to the study of marginal filters (MF) in the Severnaya Dvina, Onega, and Kem rivers. Three microalgal assemblages are established in surface sediments, which replace each other successively with distance from river mouths and are characterized by a gradual decrease in a share of freshwater species of diatoms and Chlorophyceae algae, significantly varying concentrations of marine diatoms and dinocysts due to changes in water salinity, grain-size composition of sediments, quantitative distribution of suspended particulate matter (SPM), and water productivity at different marginal filter stages.

Testing the validity of productivity proxy indicators in high altitude Tso Moriri Lake, NW Himalaya (India)

We use multiple proxies (δ13Corg, δ15Norg, C/N, amino acids, biogenic silica) from the catchment, lake surface and core sediments to (i) identify the factors influencing conventional lacustrine primary productivity (LPP) indicators (isotopic covariance, C/N) in the sediments from the pristine high altitude Tso Moriri Lake during the late Quaternary, (ii) compare C/N and bulk organic isotopic data from the core with available biogenic silica and amino acid data to test the applicability of conventional LPP indicators during the late Quaternary, and (iii) evaluate the degree of sensitivity of LPP to climate change. Our results show that climate driven changes in water salinity and source water changes have influenced the isotopic (δ13C, δ15N) content of the lake water and hence the isotopic composition of bulk organic matter. Erosion has also played a role in masking the LPP as the catchment sediments from this high altitude lake have low C/N thereby casting doubt on the effectiveness of this parameter as an LPP indicator. Independent LPP indicators in Tso Moriri sediments clearly indicate that it is driven by climate change and increases during warmer periods. However, our data show that the LPP in recent times is not much higher than during the early Holocene, ruling out any impact of recent warming on LPP and therefore the possibility of large carbon sequestration in high altitude oligotrophic lakes.

First freshwater coralline alga and the role of local features in a major biome transition.

Coralline red algae are significant components of sea bottom and up to now considered as exclusively marine species. Here we present the first coralline alga from a freshwater environment, found in the Cetina River (Adriatic Sea watershed). The alga is fully adapted to freshwater, as attested by reproductive structures, sporelings, and an inability to survive brackish conditions. Morphological and molecular phylogenetic analyses reveal the species belongs to Pneophyllum and is described as P. cetinaensis sp. nov. The marine-freshwater transition most probably occurred during the last glaciation. The brackish-water ancestor was preadapted to osmotic stress and rapid changes in water salinity and temperature. The particular characteristics of the karst Cetina River, such as hard water enriched with dissolved calcium carbonate and a pH similar to the marine environment, favoured colonization of the river by a marine species. The upstream advance and dispersal is facilitated by exceptionally pronounced zoochory by freshwater gastropods. Pneophyllum cetinaensis defies the paradigm of Corallinales as an exclusively marine group.

Hormonal Regulation of Adaptive Processes in Fishes to Impact of Abiotic Factors (a Review)

Literature data on functional significance of selected hormones in the vital activity of fishes were considered. It was shown that prolactin is actively involved in fish adaptation to the freshwater environment, cortisol and growth hormone promote fish adaptation to saline water and regulate processes associated with growth, forming of eggs and immunity. Joint effects of these hormones over changes of water salinity were analyzed. Adaptive role of hormones of thyroid and adrenal glands in the development of stress reactions of different fishes to changes of habitat conditions was considered.