scholarly journals A product of its environment: the epaulette shark (Hemiscyllium ocellatum) exhibits physiological tolerance to elevated environmental CO2

2014 ◽  
Vol 2 (1) ◽  
pp. cou047-cou047 ◽  
Author(s):  
D. D. U. Heinrich ◽  
J. L. Rummer ◽  
A. J. Morash ◽  
S.-A. Watson ◽  
C. A. Simpfendorfer ◽  
...  
Keyword(s):  
Physiological Tolerance ◽  
Epaulette Shark

CYLINDROSPERMOPSIS RACIBORSKII (CYANOBACTERIA) INVASION AT MID-LATITUDES: SELECTION, WIDE PHYSIOLOGICAL TOLERANCE, ORGLOBALWARMING?1

2004 ◽  
Vol 40 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Jean-François Briand ◽  
Christophe Leboulanger ◽  
Jean-François Humbert ◽  
Cécile Bernard ◽  
Philippe Dufour
Keyword(s):  
Cylindrospermopsis Raciborskii ◽  
Physiological Tolerance

scholarly journals Ecotones and gradient as determinants of herpetofaunal community structure in the primary forest of Mount Kupe, Cameroon

2000 ◽  
Vol 16 (4) ◽  
pp. 517-533 ◽  
Author(s):  
Ulrich Hofer ◽  
Louis-Félix Bersier ◽  
Daniel Borcard
Keyword(s):  
Forest Type ◽  
Variation Partitioning ◽  
Null Model ◽  
Elevational Gradient ◽  
Community Response ◽  
Primary Forest ◽  
Minor Importance ◽  
Breeding Sites ◽  
Physiological Tolerance ◽  
The Individual

The relative effects of the elevational gradient and of environmental discontinuities (ecotones) on the structure of a herpetofaunal assemblage in a tropical upland forest were contrasted by means of canonical correspondence analysis. Qualitative descriptors were used to define the elevational positions of the ecotones of interest, namely transitions in forest type and presence/absence of water bodies. The elevational gradient was coded in a form that accommodated different types of community response. Analyses were run for four subsets of the entire assemblage: (1) reptiles, (2) amphibians, (3) amphibians dependent on streams for reproduction, and (4) amphibians that do not use streams for reproduction. All subsets showed a significant relationship with the gradient, which suggested that most species respond to the physical continuum associated with the change in elevation. A response to ecotones was revealed for the amphibian subset only and associated with the presence or absence of watercourses. However, this response disappeared within subsets 3 and 4. A variation partitioning analysis was used to assess the individual and common contributions of gradient and ecotone descriptors to the elevational variation in the structure of subsets 1 and 2. The gradient descriptors explained more variation in the reptile subset than did ecotones, while the reverse was found in the amphibian subset. The dependence of most amphibians on aquatic breeding sites that were not available at all elevations reduced the relative importance of the gradient on the species distributions in subset 2 and accounted for the difference to the reptiles. In all, these findings add to the results of previous null model tests on the same four subsets, where competitive interactions were assigned a minor importance in limiting elevational distributions. The response patterns revealed by the present approach, with ecotones and gradient contrasted in a single analysis, emphasised the role of individual responses to the gradient according to the species' physiological tolerance limits.

scholarly journals Survival and osmoregulation of the purple marsh crab (Sesarma reticulatum) at varying salinity and pH

2017 ◽  
Vol 95 (12) ◽  
pp. 985-989 ◽  
Author(s):  
C.A. Shaughnessy ◽  
E.C. Anderson ◽  
M. Kasparian ◽  
J.M. LaMontagne ◽  
J.S. Bystriansky
Keyword(s):  
South Carolina ◽  
Salt Marshes ◽  
Trophic Cascade ◽  
Western Atlantic ◽  
Fundamental Niche ◽  
Ion Concentrations ◽  
Physiological Tolerance ◽  
Physiological Limits ◽  
Top Predators ◽  
Sesarma Reticulatum

Overfishing of top predators along the western Atlantic coastline has led to a trophic cascade in salt marshes, with increases in herbivorous purple marsh crab (Sesarma reticulatum (Say, 1817)) abundances in North American estuaries leading to overgrazing of cordgrass (Spartina alterniflora Loisel.) and shoreline erosion. To evaluate potential physiological limits on the range of S. reticulatum within an estuary, we evaluated survival and physiological tolerance of S. reticulatum from the Ashepoo–Combhee–Edisto (ACE) River Basin in South Carolina, USA, to combinations of salinity (5‰ and 30‰) and pH (pH 6.6, 7.6, and 8.6) challenges, representative of estuarine extremes. Survival, haemolymph ion concentrations, and gill Na+,K+-ATPase (NKA) and vacuolar-type H+-ATPase (VHA) activity were measured after a 48 h exposure to each experimental condition. Survival was nearly 100% and osmoregulatory control was maintained across estuarine salinity and pH ranges. Sesarma reticulatum appeared to be robust to all potential combinations of salinity and pH stressors examined in this study, and therefore are likely unrestricted in their fundamental niche based on these stressors throughout an estuary.

scholarly journals Acclimatization to high-variance habitats does not enhance physiological tolerance of two key Caribbean corals to future temperature and pH

2016 ◽  
Vol 283 (1831) ◽  
pp. 20160442 ◽  
Author(s):  
Emma F. Camp ◽  
David J. Smith ◽  
Chris Evenhuis ◽  
Ian Enochs ◽  
Derek Manzello ◽  
...  
Keyword(s):  
Climate Change ◽  
Future Climate ◽  
Seagrass Beds ◽  
Metabolic Rates ◽  
Acropora Palmata ◽  
Climate Scenarios ◽  
Environmental Variance ◽  
Outer Reef ◽  
Porites Astreoides ◽  
Physiological Tolerance

Corals are acclimatized to populate dynamic habitats that neighbour coral reefs. Habitats such as seagrass beds exhibit broad diel changes in temperature and pH that routinely expose corals to conditions predicted for reefs over the next 50–100 years. However, whether such acclimatization effectively enhances physiological tolerance to, and hence provides refuge against, future climate scenarios remains unknown. Also, whether corals living in low-variance habitats can tolerate present-day high-variance conditions remains untested. We experimentally examined how pH and temperature predicted for the year 2100 affects the growth and physiology of two dominant Caribbean corals ( Acropora palmata and Porites astreoides ) native to habitats with intrinsically low (outer-reef terrace, LV) and/or high (neighbouring seagrass, HV) environmental variance. Under present-day temperature and pH, growth and metabolic rates (calcification, respiration and photosynthesis) were unchanged for HV versus LV populations. Superimposing future climate scenarios onto the HV and LV conditions did not result in any enhanced tolerance to colonies native to HV. Calcification rates were always lower for elevated temperature and/or reduced pH. Together, these results suggest that seagrass habitats may not serve as refugia against climate change if the magnitude of future temperature and pH changes is equivalent to neighbouring reef habitats.

scholarly journals Weathering the impacts of climate change

2020 ◽  
pp. 227-238
Author(s):  
Brian Helmuth
Keyword(s):  
Climate Change ◽  
Environmental Conditions ◽  
Quantitative Methods ◽  
Heat Waves ◽  
Heat Budget ◽  
Spatial Scales ◽  
Physiological Tolerance ◽  
Physiological Processes ◽  
Local Environments ◽  
Sessile Organisms

Ectothermic organisms experience their local environments in ways that humans can have difficulty conceptualizing. Physics-based (ecomechanical) approaches, for example heat budget models, can lend insights into how an organism’s very local environmental conditions (microclimate) can drive niche-level conditions such as body temperature; these in turn drive physiological processes. Quantitative methods also allow insights into the temporal and spatial scales that may ultimately determine responses to larger-scale environmental change. For example, for small, sessile organisms, microhabitats such as crevices in rocks may provide microrefugia that allow survival during heat waves. As a result, larger-scale recovery following heat waves (rescue effects) may ultimately be influenced by much smaller-scale processes. Ecomechanics techniques also facilitate the use of interventions such as shading that can maintain environmental conditions within physiological tolerance levels.

scholarly journals Collecting eco-evolutionary data in the dark: Impediments to subterranean research and how to overcome them

2020 ◽  
Author(s):  
Stefano Mammola ◽  
Enrico Lunghi ◽  
Helena Bilandžija ◽  
Pedro Cardoso ◽  
Volker Grimm ◽  
...  
Keyword(s):  
Model Systems ◽  
Ex Situ ◽  
Model Organisms ◽  
Physiological Tolerance ◽  
Advantages And Disadvantages ◽  
General Scientific ◽  
Experimental Model Systems ◽  
Scientific Questions ◽  
Subterranean Species

(1) Caves and other subterranean habitats fulfill the requirements of experimental model systems to address general questions in ecology and evolution. Yet, the harsh working conditions of these environments and the uniqueness of the subterranean organisms have challenged most attempts to pursuit standardized research(2) Two main obstacles have synergistically hampered previous attempts. First, there is a habitat impediment related to the objective difficulties of exploring subterranean habitats and our inability to access the network of fissures that represent the elective habitat for the so-called “cave species.” Second, there is a biological impediment illustrated by the rarity of most subterranean species and their low physiological tolerance, often limiting sample size and complicating lab experiments.(3) We explore the advantages and disadvantages of four general experimental setups (in-situ, quasi in-situ, ex-situ, and in-silico) in the light of habitat and biological impediments. We also discuss the potential of indirect approaches to research. Furthermore, using bibliometric data, we provide a quantitative overview of the model organisms that scientists have exploited in the study of subterranean life.(4) Our over-arching goal is to promote caves as model systems where one can perform standardised scientific research. This is important not only to achieve an in-depth understanding of the functioning of subterranean ecosystems but also to fully exploit their long-discussed potential in addressing general scientific questions with implications beyond the boundaries of this discipline.

Fundamental processes within natural and constructed wetland ecosystems: short-term versus long-term objectives

2001 ◽  
Vol 44 (11-12) ◽  
pp. 1-8 ◽  
Author(s):  
R.G. Wetzel
Keyword(s):  
Pollution Control ◽  
Life History Strategies ◽  
Short Term ◽  
Water Losses ◽  
Wetland Ecosystems ◽  
Biological Communities ◽  
Physiological Tolerance ◽  
Species Succession ◽  
Standing Dead

Use of wetland ecosystems for water pollution control consists essentially of sustained induced disturbances as pollutants are loaded to complex biological communities. Objectives are to maximize pollutant loading, incorporation, and retention while maintaining highest levels of community metabolism and minimal alteration of community structure. Several basic processes are emphasized: (a) macrophyte productivity in relation to shoot:root ratios, and nutrient availability; (b) macrophyte life history strategies, succession, and biodiversity under constant pollutant stress; (c) importance of standing dead and particulate detritus; (d) functions and controlling mechanisms of heterotrophic and autotrophic periphyton in pollutant retention and recycling; (e) coupling of microbial metabolism to macrophyte retention of pollutants; (f) gaseous losses to the atmosphere; (g) losses of dissolved organic matter and its utilization; and (h) water losses by evapotranspiration and effects on wetland efficacy. Short-term wetland removal efficiencies are confounded by massive variations in retentive capacities diurnally, seasonally, and spatially, in exceeding physiological tolerance levels, and in species succession. Problems of channelization, altered microhydrology, and assimilation/retention are major in natural and non-engineered ecosystems. Wetlands are highly ephemeral and variable in their capabilities for sequestering and retention of nutrients and other pollutants.

Sign in / Sign up

Export Citation Format

Share Document