scholarly journals Variable Environments in an Upwelling System Trigger Differential Thermal Sensitivity in a Low Intertidal Chiton

2021 ◽  
Vol 9 ◽  
Author(s):  
Nahomi Manríquez ◽  
Leonardo D. Bacigalupe ◽  
Marco A. Lardies
Keyword(s):  
Environmental Conditions ◽  
Environmental Variability ◽  
Adjacent Area ◽  
Abiotic Factor ◽  
Optimal Temperature ◽  
Critical Limit ◽  
Maximum Performance ◽  
Variable Environment ◽  
Physiological Performance ◽  
Variable Environments

Environmental variability in coastal oceans associated with upwelling dynamics probably is one of the most pervasive forces affecting the physiological performance of marine life. As the environmental temperature is the abiotic factor with major incidence in the physiology and ecology of marine ectotherms, the abrupt temperature changes in upwelling systems could generate important variations in these organisms’ functional processes. The relationship between ambient temperature and physiological performance can be described through a thermal performance curve (TPC). The parameters of this curve usually show geographic variation usually is in accordance with the predictions of the climate variability hypothesis (CVH), which states that organisms inhabiting more variable environments should have broader ranges of environmental tolerance in order to cope with the fluctuating environmental conditions they experience. Here we study the effect generated by the environmental variability in an active upwelling zone on the physiological performance of the marine ectotherm Achanthopleura echinata. In particular, we compared the parameters of the TPC and the metabolic rate of two populations of A. echinata, one found in high semi-permanent upwelling (Talcaruca), while the other is situated in an adjacent area with seasonal upwelling (Los Molles) and therefore more stable environmental conditions. Our results show that: (1) oxygen consumption increases with body size and this effect is more significant in individuals from the Talcaruca population, (2) optimal temperature, thermal breadth, upper critical limit and maximum performance were higher in the population located in the area of high environmental heterogeneity and (3) individuals from Talcaruca showed greater variance in optimal temperature, thermal breadth, upper critical limit but not in maximum performance. Although it is clear that a variable environment affects the thermal physiology of organisms, expanding their tolerance ranges and generating energy costs in the performance of individuals, it is relevant to note that upwelling systems are multifactorial phenomena where the rise of water masses modifies not only temperature, but also decreases O2, pH, and increases pCO2 which in turn could modify metabolism and TPC.

scholarly journals The fate of a mutation in a fluctuating environment

2015 ◽  
Author(s):  
Ivana Cvijovic ◽  
Benjamin H. Good ◽  
Elizabeth R. Jerison ◽  
Michael M. Desai
Keyword(s):  
Environmental Variability ◽  
Natural Environments ◽  
New Mutation ◽  
Selection Pressures ◽  
Variable Environment ◽  
Selective Effect ◽  
Selective Pressures ◽  
Variable Environments ◽  
Fixation Probabilities ◽  
Efficiency Of Selection

Natural environments are never truly constant, but the evolutionary implications of temporally varying selection pressures remain poorly understood. Here we investigate how the fate of a new mutation in a variable environment depends on the dynamics of environmental fluctuations and on the selective pressures in each condition. We find that even when a mutation experiences many environmental epochs before fixing or going extinct, its fate is not necessarily determined by its time-averaged selective effect. Instead, environmental variability reduces the efficiency of selection across a broad parameter regime, rendering selection unable to distinguish between mutations that are substantially beneficial and substantially deleterious on average. Temporal fluctuations can also dramatically increase fixation probabilities, often making the details of these fluctuations more important than the average selection pressures acting on each new mutation. For example, mutations that result in a tradeoff between conditions but are strongly deleterious on average can nevertheless be more likely to fix than mutations that are always neutral or beneficial. These effects can have important implications for patterns of molecular evolution in variable environments, and they suggest that it may often be difficult for populations to maintain specialist traits, even when their loss leads to a decline in time-averaged fitness.

scholarly journals Fatty acid composition and parasitism of European sardine (Sardina pilchardus) and European anchovy (Engraulis encrasicolus) populations in the northern Catalan Sea in the context of changing environmental conditions

2020 ◽  
Author(s):  
Sebastian Biton-Porsmoguer ◽  
Ricard Bou ◽  
Elsa Lloret ◽  
Manuel Alcaide ◽  
Josep Lloret
Keyword(s):  
Fatty Acid ◽  
Environmental Conditions ◽  
Total Lipid Content ◽  
Taxonomic Composition ◽  
The Body ◽  
Adjacent Area ◽  
Poor Condition ◽  
Lipid Dynamics ◽  
Phytoplankton Communities ◽  
The Status

AbstractThe status of sardine and anchovy populations in the northern Mediterranean Sea has been declining in recent decades. In this study, fatty acids and parasitism at different reproductive and feeding stages in these two species were assessed using specimens caught along the northern Catalan coast, in order to assess the links between lipid dynamics, reproduction and feeding in these two species, and to contribute towards an explanation of the potential causes of the current situation of the stocks. The results support the use of fatty acid levels as indicators of the body condition of sardine and anchovy at different reproductive and feeding stages, as well as that of the pelagic environmental conditions. In particular, the relatively low n-3 PUFA levels (which are crucial for reproductive success) found in spawning sardines compared to spawning anchovies indicate a poorer reproductive health status of sardine. By comparing the current total lipid content values with those recorded in other Mediterranean and North Atlantic areas, and, others from more than ten years ago, in the adjacent area of the Gulf of Lion, our study reveals the persistent poor condition of sardine and anchovy in the northern Catalan Sea. Furthermore, the low levels of diatom fatty acid markers observed throughout the spawning and non-spawning seasons in both sardine and anchovy, indicate a diet poor in diatoms. Moreover, the results indicate that it is very unlikely that parasitism is a significant factor in the decline in condition of sardine and anchovy in the northern Catalan Sea. In fact, the results suggest that the current poor condition of sardine and anchovy in the northern Catalan Sea has been exacerbated by a decrease in plankton productivity and/or a shift in the taxonomic composition of phytoplankton communities, adding to the ongoing effects of overfishing.

scholarly journals Timing in a fluctuating environment: environmental variability and asymmetric fitness curves can lead to adaptively mismatched avian reproduction

2012 ◽  
Vol 279 (1741) ◽  
pp. 3161-3169 ◽  
Author(s):  
Marjolein E. Lof ◽  
Thomas E. Reed ◽  
John M. McNamara ◽  
Marcel E. Visser
Keyword(s):  
Temporal Variation ◽  
Environmental Variability ◽  
Environmental Variation ◽  
Reaction Norm ◽  
Optimal Timing ◽  
Variable Environment ◽  
Avian Reproduction ◽  
Breeding Date ◽  
Fitness Curve ◽  
Warming World

Adaptation in dynamic environments depends on the grain, magnitude and predictability of ecological fluctuations experienced within and across generations. Phenotypic plasticity is a well-studied mechanism in this regard, yet the potentially complex effects of stochastic environmental variation on optimal mean trait values are often overlooked. Using an optimality model inspired by timing of reproduction in great tits, we show that temporal variation affects not only optimal reaction norm slope, but also elevation. With increased environmental variation and an asymmetric relationship between fitness and breeding date, optimal timing shifts away from the side of the fitness curve with the steepest decline. In a relatively constant environment, the timing of the birds is matched with the seasonal food peak, but they become adaptively mismatched in environments with temporal variation in temperature whenever the fitness curve is asymmetric. Various processes affecting the survival of offspring and parents influence this asymmetry, which collectively determine the ‘safest’ strategy, i.e. whether females should breed before, on, or after the food peak in a variable environment. As climate change might affect the (co)variance of environmental variables as well as their averages, risk aversion may influence how species should shift their seasonal timing in a warming world.

scholarly journals Environmental uncertainty, autocorrelation and the evolution of survival

2007 ◽  
Vol 274 (1622) ◽  
pp. 2153-2160 ◽  
Author(s):  
C.J.E Metcalf ◽  
D.N Koons
Keyword(s):  
Evolutionary Biology ◽  
Environmental Variability ◽  
Variable Density ◽  
Allocation Of Resources ◽  
Fitness Component ◽  
Fitness Components ◽  
Temporal Autocorrelation ◽  
Variable Environments ◽  
Survival Patterns ◽  
Evolutionarily Stable

Survival is a key fitness component and the evolution of age- and stage-specific patterns in survival is a central question in evolutionary biology. In variable environments, favouring chances of survival at the expense of other fitness components could increase fitness by spreading risk across uncertain conditions, especially if environmental conditions improve in the future. Both the magnitude of environmental variation and temporal autocorrelation in the environment might therefore affect the evolution of survival patterns. Despite this, the influence of temporal autocorrelation on the evolution of survival patterns has not been addressed. Here, we use a trade-off structure which reflects the empirically inspired paradigm of acquisition and allocation of resources to investigate how the evolutionarily stable survival probability is shaped in variable, density-dependent environments. We show that temporal autocorrelation is likely to be an important aspect of environmental variability that contributes to shaping age- and stage-specific patterns of survival probabilities in nature.

scholarly journals Fate of a mutation in a fluctuating environment

2015 ◽  
Vol 112 (36) ◽  
pp. E5021-E5028 ◽  
Author(s):  
Ivana Cvijović ◽  
Benjamin H. Good ◽  
Elizabeth R. Jerison ◽  
Michael M. Desai
Keyword(s):  
Environmental Variability ◽  
Natural Environments ◽  
New Mutation ◽  
Selection Pressures ◽  
Selective Effect ◽  
Selective Pressures ◽  
Fluctuating Environment ◽  
Variable Environments ◽  
Fixation Probabilities ◽  
Efficiency Of Selection

Natural environments are never truly constant, but the evolutionary implications of temporally varying selection pressures remain poorly understood. Here we investigate how the fate of a new mutation in a fluctuating environment depends on the dynamics of environmental variation and on the selective pressures in each condition. We find that even when a mutation experiences many environmental epochs before fixing or going extinct, its fate is not necessarily determined by its time-averaged selective effect. Instead, environmental variability reduces the efficiency of selection across a broad parameter regime, rendering selection unable to distinguish between mutations that are substantially beneficial and substantially deleterious on average. Temporal fluctuations can also dramatically increase fixation probabilities, often making the details of these fluctuations more important than the average selection pressures acting on each new mutation. For example, mutations that result in a trade-off between conditions but are strongly deleterious on average can nevertheless be more likely to fix than mutations that are always neutral or beneficial. These effects can have important implications for patterns of molecular evolution in variable environments, and they suggest that it may often be difficult for populations to maintain specialist traits, even when their loss leads to a decline in time-averaged fitness.

Net assimilation rate of wheat as affected by light intensity and temperature

1969 ◽  
Vol 47 (11) ◽  
pp. 1781-1787 ◽  
Author(s):  
D. J. C. Friend
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Relative Proportion ◽  
Net Assimilation Rate ◽  
Continuous Illumination ◽  
Assimilation Rate ◽  
Direct Effects ◽  
Optimal Temperature ◽  
Area Basis ◽  
Net Assimilation

The net assimilation rate of wheat, on a leaf area basis, declined with time under constant environmental conditions. With continuous illumination at temperatures of 20, 25, and 30 °C, the net assimilation rate increased linearly with increases in the light intensity over the range 200 to 5000 ft-c. The optimal temperature was 15 to 20 °C, and the net assimilation rate declined with increases in temperature over the range 20 to 30 °C. These responses are related to direct effects of light intensity on apparent rates of leaf photosynthesis and to changes in the relative proportion of photosynthetic and primarily respiratory organs under different environmental conditions.

scholarly journals Influence of environmental variability on harbour porpoise movement

2020 ◽  
Vol 648 ◽  
pp. 207-219 ◽  
Author(s):  
D Stalder ◽  
FM van Beest ◽  
S Sveegaard ◽  
R Dietz ◽  
J Teilmann ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Marine Mammals ◽  
Large Scale ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Environmental Variability ◽  
Conservation Status ◽  
Movement Patterns ◽  
Environmental Parameters ◽  
Harbour Porpoise

The harbour porpoise Phocoena phocoena is a small marine predator with a high conservation status in Europe and the USA. To protect the species effectively, it is crucial to understand its movement patterns and how the distribution of intensively used foraging areas can be predicted from environmental conditions. Here, we investigated the influence of both static and dynamic environmental conditions on large-scale harbour porpoise movements in the North Sea. We used long-term movement data from 57 individuals tracked during 1999-2017 in a state-space model to estimate the underlying behavioural states, i.e. whether animals used area-restricted or directed movements. Subsequently, we assessed whether the probability of using area-restricted movements was related to environmental conditions using a generalized linear mixed model. Harbour porpoises were more likely to use area-restricted movements in areas with low salinity levels, relatively high chlorophyll a concentrations and low current velocity, and in areas with steep bottom slopes, suggesting that such areas are important foraging grounds for porpoises. Our study identifies environmental parameters of relevance for predicting harbour porpoise foraging hot spots over space and time in a dynamic system. The study illustrates how movement patterns and data on environmental conditions can be combined, which is valuable to the conservation of marine mammals.

scholarly journals Expression of some salt tolerance genes isolated from Egyptian gray mangrove (Avicennia marina)

2021 ◽  
Vol 53 (4) ◽  
pp. 685-696
Author(s):  
A.A. El-Atawy ◽  
M.S. Rizk ◽  
E.S. El-Demerdash ◽  
M.Z.S. Ahmed
Keyword(s):  
Salt Tolerance ◽  
Environmental Conditions ◽  
Expression Patterns ◽  
Avicennia Marina ◽  
High Light Intensity ◽  
Abiotic Factor ◽  
Low Oxygen ◽  
South Sinai ◽  
Cultivable Land ◽  
Ferritin Gene

Mangroves are well-adapted halophytes that thrive in coastal saline environments. They live under difficult environmental conditions, such as high light intensity and external salt concentrations, as well as low-oxygen environments, such as water-logged muck, that are typically inappropriate for the survival of other plants. Salinity is a major abiotic factor that affects plant growth, productivity, and dispersal in tropical and semitropical intertidal areas. Furthermore, it affects approximately 20% of all cultivable land and 50% of all irrigated land on the planet. Mangroves have developed a sophisticated salt filtration mechanism and a complicated root structure to withstand salty water exposure and tidal movement. The expression patterns of five salt tolerance genes (amFer1, amDhna, amSod1, amCat1, and amUbc2) in the Egyptian gray mangrove (Avicennia marina Forssk.) grown under different environmental conditions in South Sinai protectorates (Nabq, Ras Mohamed, Safaga, and Wadi El-Gemal), Egypt, were investigated in this study. This study aimed to assess and examine the genetic behavior of mangroves in response to salinity by using quantitative real-time PCR. Findings revealed differences in the expression patterns of the investigated genes under various conditions, showing that salinity influences plant genetic response. Ferritin gene expression was high in all locations, indicating that ferritin represents an essential component of the mangrove response mechanisms.

scholarly journals Canopy phenology of a dry forest in western Brazil

2007 ◽  
Vol 67 (3) ◽  
pp. 569-575 ◽  
Author(s):  
J. Ragusa-Netto ◽  
RR. Silva
Keyword(s):  
Environmental Conditions ◽  
Dry Season ◽  
Dry Forest ◽  
Abiotic Factor ◽  
Deciduous Species ◽  
Ecological Processes ◽  
Canopy Trees ◽  
Dry Conditions ◽  
Leaf Shedding ◽  
Mountain Chain

Dry forests are common, although highly threatened in the Neotropics. Their ecological processes are mostly influenced by rainfall pattern, hence their cycles exhibit contrasting phases. We studied the phenology of canopy trees in a primary dry forest in Western Brazil in the foothills of the Urucum mountain chain, in order to improve our knowledge on the functioning of these poorly-known forests. Leaf shedding started in the early dry season and was massive in the latter part of this period. Most leaf loss occurred in dry hills, while wet valleys remained evergreen. Anemochorich and autochorich species predominated in dry hills, presumably due to their tolerance to dry conditions and enhanced exposition to winds, which favour diaspores removal and dispersal. Conversely, zoochorich species dominated the wet valleys. Flowering was intense in the late dry season, the driest period of the year, while fruiting was massive just after the onset of rains, as well as flushing. Therefore, most flowering was unrelated to wet conditions, although such an abiotic factor, potentially, triggered the major fruiting episode, widely comprised by zoochorich species. Anemochorich and autochorich species flowered and fruited in the course of the long dry season. The contrasting environmental conditions present in the hills and valleys determine the arrangement of a mosaic in which patches of zoochorich and evergreen trees alternate with patches of non zoochorich and highly deciduous species. Consequently, species with such syndromes exhibited marked flowering and fruiting patterns, accordingly to the pronounced seasonality.

Predicting catch per unit effort from a multispecies commercial fishery in Port Phillip Bay, Australia

2020 ◽  
Vol 71 (4) ◽  
pp. 542
Author(s):  
Karina L. Ryan ◽  
Denny Meyer
Keyword(s):  
Time Series ◽  
Environmental Conditions ◽  
Environmental Variability ◽  
Moving Average ◽  
Commercial Fishing ◽  
Arima Models ◽  
Catch Per Unit Effort ◽  
Explanatory Variables ◽  
Unit Effort ◽  
Stock Abundance

Quantitative models that predict stock abundance can inform stock assessments and adaptive management that allows for less stringent controls when abundance is high and environmental conditions are suitable, or tightening controls when abundance is low and environmental conditions are least suitable. Absolute estimates of stock abundance are difficult and expensive to obtain, but data from routine reporting in commercial fisheries logbooks can provide an indicator of stock status. Autoregressive integrated moving average (ARIMA) models were constructed using catch per unit effort (CPUE) from commercial fishing in Port Phillip Bay from 1978–79 to 2009–10. Univariate and multivariate models were compared for short-lived species (Sepioteuthis australis), and species represented by 1–2 year-classes (Sillaginodes punctatus) and 5–6 year-classes (Chrysophrys auratus). Simple transfer models incorporating environmental variables produced the best predictive models for all species. Multivariate ARIMA models are dependent on the availability of an appropriate time series of explanatory variables. This study demonstrates an application of time series methods to predict monthly CPUE that is relevant to fisheries for species that are short lived or vulnerable to fishing during short phases in their life history or where high intra-annual variation in stock abundance occurs through environmental variability.

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