Publication Date:
2021-05-25
Description:
Developing physiological mechanistic models to predict species’ responses to climate-driven
environmental variables remains a key endeavor in ecology. Such approaches
are challenging, because they require linking physiological processes with fitness and
contraction or expansion in species’ distributions. We explore those links for coastal
marine species, occurring in regions of freshwater influence (ROFIs) and exposed to
changes in temperature and salinity. First, we evaluated the effect of temperature on
hemolymph osmolality and on the expression of genes relevant for osmoregulation in
larvae of the shore crab Carcinus maenas. We then discuss and develop a hypothetical
model linking osmoregulation, fitness, and species expansion/contraction toward or
away from ROFIs. In C. maenas, high temperature led to a threefold increase in the
capacity to osmoregulate in the first and last larval stages (i.e., those more likely to
experience low salinities). This result matched the known pattern of survival for larval
stages where the negative effect of low salinity on survival is mitigated at high temperatures
(abbreviated as TMLS). Because gene expression levels did not change at
low salinity nor at high temperatures, we hypothesize that the increase in osmoregulatory
capacity (OC) at high temperature should involve post-translational
processes.
Further analysis of data suggested that TMLS occurs in C. maenas larvae due to the
combination of increased osmoregulation (a physiological mechanism) and a reduced
developmental period (a phenological mechanisms) when exposed to high temperatures.
Based on information from the literature, we propose a model for C. maenas
and other coastal species showing the contribution of osmoregulation and phenological
mechanisms toward changes in range distribution under coastal warming. In
species where the OC increases with temperature (e.g., C. maenas larvae), osmoregulation
should contribute toward expansion if temperature increases; by contrast in
those species where osmoregulation is weaker at high temperature, the contribution
should be toward range contraction.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
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