Effects Of Salinity Fluctuations Research Articles

The effect of salinity fluctuation in freshwater streams on the fecundity of post-diapause Chironomus dilutus.

Much scientific research dedicated to understanding the effects of freshwater salinization caused by road de-icing salts has utilized static exposures, with many tests conducted at winter or spring temperatures. While relevant for lentic ecosystems, pulsed patterns of salinity occur in lotic environments, particularly in summer months where precipitation can decrease elevated salinity levels caused by retention of residual salts. The current study aimed to evaluate the effects of pulsed patterns of salinity on the emergence, sex ratio, and fecundity of Chironomus dilutus over two generations of laboratory exposure. Three road de-icing salt treatments, including a control, modeled after environmental monitoring data of two local streams, were used to determine the ecological effects of periodic declines in salinity on C. dilutus at summer temperatures. No significant effects were observed on emergence success or sex ratios within or across generations, but fecundity of C. dilutus in the high salt treatment was reduced regardless of generation (P < 2e-16), possibly due to increased osmoregulatory stress caused by increased salinities. The intermediate and decreasing salinities may account for the lack of negative effects on emergence success and sex ratios by protecting sensitive life stages. More research is needed on long-term effects of reduced fecundity on population viability. The current study suggests more research using a similar experimental design is needed to fully evaluate the influence of road de-icing salts in lotic environments, as static laboratory exposures may not accurately reflect environmental changes in salinity.

Effect of salinity fluctuation on the transcriptome of the Japanese mantis shrimp Oratosquilla oratoria

Salinity fluctuation may detrimentally affect the composition and biological processes of crustaceans. As a euryhaline crustacean, Oratosquilla oratoria can survive at salinities ranging from 20 psu to 40 psu. Therefore, we designed five salinity gradients (20, 25, 30, 35, and 40 psu) and 66.39 Gb clean transcriptome data were obtained after O. oratorias were exposed to each gradient for 24 h. All clean data were spliced into 50,482 unigenes and 17,035 unigenes were annotated in at least one database. Compared with 30 psu, 1010, 851, 1733 and 2188 differentially expressed genes were obtained at 20, 25, 35 and 40 psu, respectively. Results also showed that the osmoregulation of O. oratoria is primarily regulated by lipid and amino acid metabolism, amongst others. No significant up-regulated pathways were enriched at 25 psu and 35 psu, although more significant down-regulated pathways were obtained at 35 psu. Therefore, we assumed that the optimum survival salinity of O. oratoria may range from 25 psu to 35 psu. However, 35 psu may be more suitable for O. oratoria. In addition, 55 unigenes that encode putative inorganic ion exchanges were identified. This study aims to provide fundamental information for understanding the osmoregulation mechanisms of crustaceans.

A comprehensive comparison between halophilic granular and flocculent sludge in withstanding short and long-term salinity fluctuations

The effects of salinity fluctuations on the activity of autochthonous halophilic bacteria in aerobic granular sludge (AGS) and flocculent activated sludge (FAS) reactors were investigated. The response of nitrifiers and denitrifiers activity to drastic and moderate salinity shocks in the short-term (ST) and long-term (LT) was examined.The BOD5 removal efficiency decreased only in the reactors subjected to the drastic LT salinity increase. Nevertheless, stable performances were achieved 18 days after the shock in the AGS-R1 (90%), whereas after 27 days in the FAS-R1 (82%).The loss in nitritation efficiency was higher in the FAS reactors and was proportional to the shock intensity. Nitritation activity collapsed from approximately 3.8 mgNH4-N gVSS−1 h−1 to 0.73 mgNH4-N gVSS−1 h−1 and from 4.5 mgNH4-N gVSS−1 h−1 to 0.24 mgNH4-N gVSS−1 h−1 in the AGS-R1 and FAS-R1, respectively, even if the ammonium oxidation capacity did not completely disappeared. Denitritation activity decreased from 11.44 mgNO2-N gVSS−1 h−1 to 3.93 mgNO2-N gVSS−1 h−1 in the AGS-R1 at steady state, whereas in the FAS-R1, it decreased from 12.53 mgNO2-N gVSS−1 h−1 to 2.09 mgNO2-N gVSS−1 h−1.Nitritation and denitritation were completely restored 5 days after ST shock. No significant effects were observed after the moderate shock.The changes in the total EPS content were lower than 10%, therefore, it was considered negligible. Only drastic shocks caused significant changes in the EPS structure, with an increase of the loosely-bound by 45% in the AGS and 55% in the FAS.

Effects of Salinity Fluctuation on Gene Expression Profiles of Female Litopenaeus vannamei Broodstocks

In this study, the effects of salinity fluctuation on gene expression patterns in ovary and hepatopancreas of Litopenaeus vannamei were analyzed. The expression level of vitellogenin in the ovaries were significantly, markedly, and slightly, inhibited respectively in the hepatopancreas after brooders were transferred from 30‰ to 20‰ or 40‰ salinity for 4 days. The expression levels of the development of germ cell related genes Dmc1, proliferating cell nuclear antigen (PCNA) and cyclophilin A were significantly reduced at 20‰ or 40‰ salinity. The transcript level of shrimp ovarian peritrophin (SOP) was significantly reduced at 20‰ salinity, and the expression level of ovary specific gene mucin-5 AC was significantly higher at 40‰ salinity. Four stress related genes, cytoplasmic carbonic anhydrase (LvCAc), Na+/K+-ATPase alpha subunit (LvNK), V-H+-ATPase subunit A (LvVH), and heat shock protein 90 (LvHSP90), were significantly up-regulated at 40‰ salinity in the ovaries. In the hepatopancreas, the transcript level of fatty acid synthase (LvFAS) was significantly inhibited under 40‰ salinity. The mRNA levels of stress related genes LvNK, LvVH, and LvHSP90, were significantly lower at 40‰ salinity. Results indicated that changes in salinity caused transcription inhibition of germ cell and ovarian development related genes, and the expression patterns of stress related genes in the ovaries and hepatopancreas were quite different.

Influence of anisotropic turbulence on the orbital angular momentum modes of Hermite-Gaussian vortex beam in the ocean.

Applying the angular spectrum theory, we derive the expression of a new Hermite-Gaussian (HG) vortex beam. Based on the new Hermite-Gaussian (HG) vortex beam, we establish the model of the received probability density of orbital angular momentum (OAM) modes of this beam propagating through a turbulent ocean of anisotropy. By numerical simulation, we investigate the influence of oceanic turbulence and beam parameters on the received probability density of signal OAM modes and crosstalk OAM modes of the HG vortex beam. The results show that the influence of oceanic turbulence of anisotropy on the received probability of signal OAM modes is smaller than isotropic oceanic turbulence under the same condition, and the effect of salinity fluctuation on the received probability of the signal OAM modes is larger than the effect of temperature fluctuation. In the strong dissipation of kinetic energy per unit mass of fluid and the weak dissipation rate of temperature variance, we can decrease the effects of turbulence on the received probability of signal OAM modes by selecting a long wavelength and a larger transverse size of the HG vortex beam in the source's plane. In long distance propagation, the HG vortex beam is superior to the Laguerre-Gaussian beam for resisting the destruction of oceanic turbulence.

Mangroves: obligate or facultative halophytes? A review

Salinity plays significant roles in regulating the growth and distribution of mangroves, and the salt tolerance mechanisms of mangroves have been the focus of research for several decades. There are contradictory views regarding the relationship between mangroves and salt: (1) Mangroves are facultative halophytes, i.e. freshwater is a physiological requirement and salt water is an ecological requirement for mangroves because they are capable of growing in freshwater. The former prevents excess respiratory losses while the latter prevents invasion and competition from non-halophytes. (2) Mangroves are obligate halophytes, i.e. salt is necessary for their growth. Mangroves cannot survive in freshwater permanently and salt water is a physiological requirement. Up to now, mangroves are usually considered as facultative halophytes. In this review, we provided five lines of evidence to evaluate these two contradictory views: (1) the results of laboratory culture experiments and field investigations; (2) the viviparous nature of mangroves; (3) the salt accumulation of mangroves under freshwater or low salinity; (4) the effect of salinity on the photosynthetic rate and in vitro enzyme activities, and (5) the effects of salinity fluctuation on mangrove growth and physiology. Contrary to widely accepted view, our evaluations of the aforementioned evidence suggest that mangroves are obligate halophytes. Mangroves can grow in freshwater for a limited time by drawing upon the nutrients and salt reserves in their hypocotyls while prolonged culture in freshwater is fatal to them. Mangroves have the ability to absorb Na+ and Cl− rapidly and preferentially under low-salinity conditions. Not all of the enzymes in mangroves are sensitive to salt. In fact, the activities of some enzymes are even stimulated by low or moderate salinity. Plants grown under constant salinity in a laboratory setting are unlikely to behave in the same way as those in their natural habitat with fluctuating salinity. Thus, studies on the effects of freshwater or low salinity and salinity fluctuation on mangroves, as well as the physiological mechanisms that allow maintenance of function under fluctuating salinity conditions should be strengthened in future research.

Effects of Salinity Fluctuation on the Growth and Energy Budget of Juvenile Litopenaeus vannamei at Different Temperatures

Abstract The effects of salinity fluctuation on the growth, molting and energy budget of juvenile Litopenaeus vannamei was investigated at the temperatures of 20, 25, and 30°C. Salinity fluctuation regimes were set in different amplitudes of ± 0, ± 5, ± 10 and ± 15 gL−1 from a control salinity of 20 gL−1. After a 48-day feeding trial, the lowest survival occurred at a salinity fluctuation of ± 15 gL−1 for each temperature investigated. The best growth of shrimp was obtained at salinity amplitudes of ± 5-10 gL−1 at 25 and 30°C. The salinity fluctuation influenced food conversion efficiency but not food intake. The shrimp maintained at salinity amplitudes of ± 5-10 gL−1 expended most of the energy for growth and spent less energy on respiration and excretion at 25 and 30°C. Therefore, salinity fluctuating amplitudes of ± 5-10 gL−1 result in higher growth rates than constant salinity conditions (20 gL−1) through enhanced feed assimilation and reduced energy loss in respiration and excretion.

Influence of variable salinity conditions in a tidal creek on riparian groundwater flow and salinity dynamics

While recent studies have revealed that tidal fluctuations in an estuary significantly affect groundwater flows and salt transport in the riparian zone, only seawater salinity in the estuary has been considered. A numerical study is conducted to investigate the influence of estuarine salinity variations on the groundwater flow and salt dynamics in the adjacent aquifer to extend our understanding of these complex and dynamic systems. Tidal salinity fluctuations (synchronous with estuary stage) were found to alter the magnitude and distribution of groundwater discharge to the estuary, which subsequently impacted on groundwater salinity patterns and residence times, especially in the riparian zone. The effects of salinity fluctuations were not fully captured by adopting a constant, time-averaged estuarine salinity. The modelling analysis also included an assessment of the impact of a seasonal freshwater flush in the estuary, similar to that expected in tropical climates (e.g. mean estuary level during flood significantly greater than average), on adjacent groundwater flow and salinity conditions. The three-month freshwater flushing event temporarily disrupted the salt distribution and re-circulation patterns predicted to occur under conditions of constant salinity and tidal water level fluctuations in the estuary. The results indicate that the salinity variations in tidal estuaries impact significantly on estuary-aquifer interaction and need to be accounted for to properly assess salinity and flow dynamics and groundwater residence times of riparian zones.

Effects of frequency and amplitude of salinity fluctuation on the growth and energy budget of juvenileLitopenaeus vannamei(Boone)

The effects of salinity fluctuation on the growth, intermoult period and energy budget of juvenile Litopenaeus vannamei were investigated. Salinity fluctuation regimes were set in different frequencies of 2, 4 and 8 days and different amplitudes of ±2, ±5 and ±10 g L−1 from a control salinity of 20 g L−1. After a 48-day feeding trial, the intermoult period of shrimp became shorter with increasing amplitude and frequency of salinity fluctuation (P<0.05). Both the frequency and the amplitude of salinity fluctuation had a significant effect on the growth rate of L. vannamei juveniles (P<0.05). At the frequency of 4 days, the highest growth rates occurred at amplitudes of 5–10 g L−1, whereas the growth rate was the lowest at 10 g L−1 when the frequency was reduced to 2 days. Feed intake (FI) and assimilation efficiency (AE) of shrimp were also significantly affected by the salinity fluctuation (P<0.05) and matched the growth rate response. The energy expenditures for growth (G), respiration (R), excretion (U) and exuviae (E) to the energy consumed as food (C) were not affected by salinity fluctuation. However, salinity fluctuation significantly affected the percentage of C as faeces (F), with the lowest value occurring at salinity amplitudes of 5–10 g L−1 and frequencies of 4–8 days. Therefore, salinity fluctuations (every 4 days by ±5–10 g L−1) result in higher growth rates than constant salinity conditions (20 g L−1) through greater FI, enhanced feed assimilation and reduced faecal energy loss.

Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf

The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

Effects of Salinity Fluctuations on Growth and Development of the Larvae of Marsh Frog (Rana ridibunda L)

It has been established that low water salinity (up to 2−3o/oo) has a favorable effect on growth and development of the larvae of Rana ridibunda L. The alternate keeping of larvae in fresh water and water with a low salinity results in even more accelerated growth and development. As a whole, under salinity conditions changed during 24 h (at salinity fluctuations), the duration of larval development of marsh frog is reduced by 10% as compared to constant optimal conditions. In addition, the mortality diminishes and physiological state of animals improves under changing salinity conditions.

Effects of salinity fluctuation on routine metabolism of juvenile spot, Leiostomus xanthurus

Effects of salinity fluctuation on routine metabolism of juvenile spot, Leiostomus xanthurus

Effects of salinity fluctuation on routine metabolism of juvenile spot, Leiostomus xanthums

We subjected juvenile spot, Leiostomus xanthurus, to eight different salinity fluctuation schedules to evaluate the effects of magnitude, rate, mean, and direction of salinity changes on their routine metabolism. Routine respiration stabilized within 3 h after all salinity changes and no fish died. Very rapid rates of change and changes at low mean salinity elicited short‐term stress responses in 40–70 mm spot. Spot adapted more rapidly to increasing salinity changes than to decreasing changes, but the acclimation state of the fish apparently did not affect their salinity tolerance. Our results also indicated that spot undergo size‐dependent changes in sensitivity to salinity fluctuation which correspond to seasonal shifts in distribution.

A Possible Effect of Salinity Fluctuation on Abundance of Benthic Vegetation and Associated Fauna in Northeastern Florida Bay

In southern Florida, a vast network of canals and water control structures mediate freshwater discharge into the coastal zone. Management protocol for one such canal network (C-111) is being modified in part to try to improve habitat for estuarine fish and wading birds in northeastern Florida Bay, an estuarine part of Everglades National Park. Changes in canal management could alter the spatial and temporal salinity regime in the estuary. To better predict the effect of such changes on estuarine habitat, abundances of submersed vegetation and benthic animals were sampled repeatedly at 12 stations that differed in salinity. A variety of other parameters were also measured (nutrients, light, temperature, oxygen, sediment characteristics, and others). Mean salinity among stations ranged from 11.4‰ to 33.1‰. Densities of benthic plants and animals differed among stations by several orders of magnitude. The standard deviation of salinity was the best environmental correlate with mean plant biomass and benthic animal density: less biota occurred at stations with greater fluctuations in salinity. The two stations with the least plant biomass also had the highest mean water temperatures. In a stepwise multiple regression analysis, standard deviation of salinity accounted for 59% of the variation in the logarithm of mean plant biomass among stations. For every 3‰ increase in the standard deviation, total benthic plant biomass decreased by an order of magnitude. Mean water temperature accounted for only 14% of the variation, and mean salinity was not included for lack of significance. At stations with widely fluctuating salinities, not only was biomass low, but species dominance also frequently changed. Severe fluctuation in salinity may have prevented abundant benthos by causing physiological stress that reduced growth and survival. Salinity may not have remained within the range of tolerance of any one plant species for long enough to allow the development of a substantially vegetated benthic community. Hence, gaining control over salinity fluctuation may be the key to estuarine habitat improvement through canal management in southern Florida.

Response of Hydrobia ventrosa (Montagu) to Environmental Stress: Effects of Salinity Fluctuations and Cadmium Exposure on Growth

As estuarine environments are often rich in both natural and man-induced stresses, estuarine species may provide important insights into the study of how organisms respond to stress. Exposure to cadmium concentrations of 100200 [Lg 1-1 significantly reduced growth rate of the estuarine gastropod, Hydrobia ventrosa (Montagu). Snails acclimated to 23%o salinity sea-water (S) showed reduced growth rates at 13 and 33%o S relative to snails grown at 23%o S. At 13%o S snails did not grow, and any additional effects of cadmium exposure on growth were masked. The results are not consistent with expectations based on estimated cadmium bioavailability as the relative reduction in growth in response to cadmium increased with increasing salinity. The growth trajectory of H. ventrosa at 23%o S (no cadmium) fitted a logistic growth model. Changing salinity and exposure to cadmium altered daily specific growth rates (% day-1) in a size(or time-) dependent manner such that a logistic model no longer described the growth trajectory of this species. Maximum growth rates occurred at a higher salinity than expected, based on reports of the natural distribution of H. ventrosa, and the results suggest substantial intraspecific variability in salinity tolerance in this species. Key-words: Cadmium, growth, Hydrobia, salinity

Cementation of Upper Miocene Reefs in Western Mediterranean: ABSTRACT

Coral reefs in the western Mediterranean (southeast Spain, Balearic Island, northern Morocco, Sicily, and Italy) show a wide variety of cement types, ranging from completely tight, well-cemented, to poorly cemented reefs with most of the primary porosity still preserved. Cementation processes in those coral reefs appear to be controlled to a great extent by repeated changes of relative sea levels and regional variations of seawater chemistry. Reef progradation occurred during four to six (or more) important sea level changes, resulting in complicated geometric relationships of reef complexes and their freshwater lenses. Progradation occurred during sea level rises and falls and is reflected in abrupt escarpments in some field localities, generally separated by important t rraced erosional surfaces. Various types of aragonitic isopachous cement fringes of marine origin, 0.1 to 1.5 cm (.04 to .6 in.) thick, are well preserved in some localities. This is probably due to subsequent plugging by gypsum cement during the Messinian salinity crises. Another possible effect of salinity fluctuations is the abundance of thick crusts of peletoidal, micrite cement of marine origin, locally forming about three-fourths of the volume of the reef core. End_of_Article - Last_Page 457------------

Effects of salinity fluctuations on the respiration rate of the southern oyster drill Thais haemastoma and the blue crab Callinectes sapidus

Respiration rates of Thais haemastoma and Callinectes sapidus were determined as a function of salinity with a flow-through respirometer at 20°C. Respiration rates were measured at 10, 20 and 30‰ S for acclimated animals. The effects of 10-5-10‰, 20-10-20‰, 30-10-30‰ and 10-30-10‰ S semidiurnal cycles (12 h) of fluctuating salinity on the rate of respiration of the oyster drill were studied. During each cycle, salinity was changed from the acclimation salinity over a 4 h interval, held at that salinity for 2 h, returned to the acclimation salinity over 4 h and held at that salinity for 2 h. The effects of diurnal (24.8 h) salinity cycles on respiration in the oyster drill and blue crab were also studied. Salinity was changed from the acclimation salinity over a 10.4 h interval, held at that salinity for 2 h, then returned to the acclimation salinity over 10.4 h and held at that salinity for 2 h. The respiration rate of 30‰ S acclimated oyster drills (679 μl O2 g dry weight−1 h−1) was significantly higher than for individuals acclimated to 10‰ S (534 μl O2 g dry weight−1 h−1). Blue crab respiration was 170 μl O2 g dry weight−1 h−1 at 30‰ S, and was significantly higher at 10 and 20‰ S than at 30‰ S. With the exception of the 20-10-20‰ S semidiurnal cycle, the respiration rate of oyster drills declined as salinity fluctuated in either direction from the acclimation salinity and increased as ambient salinity returned to the acclimation salinity. Semidiurnal cycles (12 h) of fluctuating salinity produced greater changes in the respiration rate of snails than analogous diurnal cycles (24.8 h). A 10-30-10‰ S pattern of fluctuation caused a greater percentage reduction in the steady state respiration rate of oyster drills than the 30-10-30‰ S pattern. The respiration rate of blue crabs varied inversely with fluctuating salinity. Relatively minor changes occurred in blue crab respiration rate with fluctuating salinity. Blue crab respiration rate characteristically dropped during the initial phase of declining salinity at a rate directly proportional to the rate of salinity decrease, perhaps representing a metabolic adjustment period by the blue crabs. The respiratory response of T. haemastoma to salinity is consistent with its incomplete volume regulation, while the response of C. sapidus is compatible with its ability to regulate extracellular fluid osmotic and ionic composition.

Effects of salinity fluctuation on the hemolymph composition of the blue crab Callinectes sapidus

The hemolymph of the blue crab Callinectes sapidus was hyperosmotic during 20-10-20‰ S and 30-10-30‰ S diurnal cycles. The hemolymph became isosmotic at 26‰ S and hyposmotic at 28‰ S in the 10-30-10‰ S diurnal cycle. Hemolymph Na+ was hyperionic to seawater throughout all cycles. Hemolymph Cl- was hyperionic below 24‰ S and either isionic or hypoionic from 24 to 30‰ S. Hemolymph K+ concentrations were hyperionic below 26‰ S and either isionic or hypoionic from 26 to 30‰ S. Hemolymph Mg++ values were hypoionic over the experimental salinity range (10 to 30‰). Hemolymph ninhydrin-positive substances (NPS) levels were directly related to ambient salinity.

Effect of salinity fluctuation on the osmotic pressure and Na+, Ca2+ and Mg2+ ion concentrations in the hemolymph of bivalve molluscs

Specimens of Chlamys opercularis, Modiolus modiolus, Mytilus edulis, Crassostrea gigas, Scrobicularia plana and Mya arenaria were exposed to both gradual (sinusoidal) and abrupt (square-wave) salinity fluctuations and measurements made of osmotic, Na+, Mg2+ and Ca2+ concentrations in the hemolymph and where applicable in the mantle fluid. In both sinusoidal and square-wave regimes fluctuating between 100 and 50% seawater (100%=ca. 32‰ S), the hemolymph Na+, Mg2+, Ca2+ and osmotic concentrations followed the concentrations of the external medium in Chlamys opercularis. The hemolymph and mantle fluid osmotic Na+, Mg2+ and Ca2+ concentrations of Modiolus modiolus, Mytilus edulis, Crassostrea gigas and S. plana followed those of the external medium as long as the molluscs' shell valves remained open. There were no changes in the ionic or osmotic concentrations of the hemolymph or mantle fluid of any of these species during periods of shell-valve closure. The hemolymph osmotic, Na+ and Mg2+ concentrations of wedged-open Modiolus modiolus, Mytilus edulis, C. gigas and S. plana followed those of the external medium. Hemolymph Ca2+ concentrations showed a damped response in C. gigas and Mytilus edulis. The hemolymph osmotic, Na+, Ca2+ and Mg2+ concentrations of Mya arenaria fluctuated in a similar manner to the external medium, but were damped. Wedged-open Mytilus edulis exposed to fluctuating salinity and supplied with a constant supply of 10 mM Ca2+ showed greater changes in hemolymph ionic and osmotic concentrations than M. edulis exposed to the same salinity fluctuation without a constant Ca2+ supply. Chlamys opercularis and Modiolus modiolus survived in a 50% seawater minimum sinusoidal salinity fluctuation for 10 days; wedged-open M. modiolus survived only 3 days. Burrowing had no effect on the osmotic, Na+, Mg2+ or Ca2+ concentrations of the hemolymph of Mya arenaria or S. plana exposed to fluctuating salinities. All of the species studied were shown to be osmoconformers.

The Effect of Salinity Fluctuations on the Life Cycle of Balanus pallidus stutsburi Darwin in Lagos Harbour, Nigeria

The Effect of Salinity Fluctuations on the Life Cycle of Balanus pallidus stutsburi Darwin in Lagos Harbour, Nigeria