ORCID Profile
0000-0003-3525-1830
Current Organisation
Universidad Adolfo Ibáñez
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Publisher: Cambridge University Press (CUP)
Date: 10-09-2014
DOI: 10.1017/S0025315413001264
Abstract: In intertidal poikilotherms with wide geographic distribution, physiological variations are ubiquitous, due to phenotypic plasticity and/or in idual geographic variation. Using the grapsid crab, Cyclograpsus cinereus as a study model, acclimatization differences in respiratory physiology were evaluated among populations along the Chilean coast, covering a latitudinal gradient of about 2000 km. This species inhabits the supratidal zones and, therefore, is subject to constant immersion and emersion periods, producing physiological acidification due to CO 2 retention, mainly in the branchial cavity. In iduals of six populations were collected along the coastline of Chile and were exposed to air for different time periods in the laboratory. The following parameters were measured: pH, Ca 2+ , Cl − and haemolymphatic lactate dehydrogenase (LDH) enzyme activity. Populations from lower latitudes were significantly different from those from central and southern Chile, with a higher haemolymphatic pH variation and higher Ca 2+ level, along with lower levels of Cl − and LDH enzyme activity. This indicates that the populations from lower latitudes, which are subject to higher air temperatures during emersion, have a higher homeostatic capacity during emersion periods than those of intermediate and higher latitudes. This response seems to be determined by genetic bases due to adaptation to the local environment.
Publisher: Wiley
Date: 10-05-2023
DOI: 10.1111/MEC.16978
Abstract: The distribution of genetic ersity is often heterogeneous in space, and it usually correlates with environmental transitions or historical processes that affect demography. The coast of Chile encompasses two biogeographic provinces and spans a broad environmental gradient together with oceanographic processes linked to coastal topography that can affect species' genetic ersity. Here, we evaluated the genetic connectivity and historical demography of four Scurria limpets, S. scurra , S. variabilis , S. ceciliana and S. araucana , between ca. 19° S and 53° S in the Chilean coast using genome‐wide SNPs markers. Genetic structure varied among species which was evidenced by species‐specific breaks together with two shared breaks. One of the shared breaks was located at 22–25° S and was observed in S. araucana and S. variabilis , while the second break around 31–34° S was shared by three Scurria species. Interestingly, the identified genetic breaks are also shared with other low‐disperser invertebrates. Demographic histories show bottlenecks in S. scurra and S. araucana populations and recent population expansion in all species. The shared genetic breaks can be linked to oceanographic features acting as soft barriers to dispersal and also to historical climate, evidencing the utility of comparing multiple and sympatric species to understand the influence of a particular seascape on genetic ersity.
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JTHERBIO.2017.02.011
Abstract: Intertidal organisms have evolved physiological mechanisms that enable them to maintain performance and survive during periods of severe environmental stress with temperatures close to their tolerance limits. The level of these adaptive responses in thermal physiology can vary among populations of broadly distributed species depending on their particular environmental context and genetic backgrounds. Here we examined thermal performances and reaction norms for metabolic rate (MR) and heart rate (HR) of seven populations of the porcelanid crab Petrolisthes violaceus from markedly different thermal environments across the latitudinal gradient of ~3000km. Physiological responses of this intertidal crab under common-garden conditions suggest the absence of local thermal adaptation along the geographic gradient (i.e., lack of latitudinal compensation). Moreover, thermal physiological sensitivities and performances in response to increased temperatures evidenced the existence of some level of: i) metabolic rate control or depression during warm temperature exposures and ii) homeostasis/canalization (i.e., absence or low levels of plasticity) in physiological traits that may reflect some sort of buffering mechanism in most of the populations. Nevertheless, our results indicate that elevated temperatures can reduce cardiac function but not metabolic rate in high latitude crabs. The lack of congruence between HR and MR supports the idea that energy metabolism in marine invertebrates cannot be inferred from HR and different conclusions regarding geographic differentiation in energy metabolism can be obtained from both physiological traits. Integrating thermal physiology and species range extent can contribute to a better understanding of the likely effects of climate change on natural populations of marine ectotherms.
Publisher: Inter-Research Science Center
Date: 14-07-2016
DOI: 10.3354/MEPS11764
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/MF14232
Abstract: Along the west coast of South America, from the tropical zone to the Patagonian waters, there is a significant latitudinal gradient in seawater temperature, salinity and carbonate chemistry. These physical–chemical changes in seawater induce morphological and physiological responses in calcifying organisms, which may alter their energy budget and calcification processes. In this study, we study the organism energy maintenance (i.e. metabolic rate) and mineralogical composition of the shell of the juvenile marine snails Concholepas concholepas (Gastropoda: Muricidae), collected from benthic populations located ~2000km apart, varies across geographic regions along the Chilean coast. We found that in juvenile snails, the calcite:aragonite ratio in the pallial shell margin (i.e. newly deposited shell) increase significantly from northern to southern populations and this increase in calcite precipitation in the shell of juveniles snails was associated with a decrease in oxygen consumption rates in these populations. Our result suggests that calcite secretion may be favoured when metabolic rates are lowered, as this carbonate mineral phase might be less energetically costly for the organism to precipitate. This result is discussed in relation to the natural process such as coastal upwelling and freshwater inputs that promote geographic variation in levels of pH and carbonate saturation state in seawater along the Chilean coast.
Publisher: The Company of Biologists
Date: 2014
DOI: 10.1242/JEB.108217
Abstract: Environmental temperature has profound implications on the biological performance and biogeographical distribution of ectothermic species. Variation of this abiotic factor across geographic gradients is expected to produces physiological differentiation and local adaptation of natural populations depending on their thermal tolerances and physiological sensitivities. Here, we have studied geographic variation in whole-organism thermal physiology of seven populations of the porcelain crab Petrolisthes violaceus across a latitudinal gradient of 3000 km, characterized by a cline of thermal conditions. Our study found that populations of P. violaceus exhibit a lack of differences in the limits of their thermal performance curves and a negative correlation of their optimal temperatures with latitude. Additionally, our findings showed that high latitude populations of P. violaceus exhibited broader thermal tolerances, which is consistent with the Climatic Variability Hypothesis. Interestingly, under a future scenario of warming oceans, the thermal safety margins of P. violaceus indicate that lower latitude populations can physiologically tolerate the ocean warming scenarios projected by the IPCC for the end of the twenty-first century.
Publisher: Wiley
Date: 31-03-2016
DOI: 10.1111/GCB.13179
Abstract: Future ocean acidification (OA) will affect physiological traits of marine species, with calcifying species being particularly vulnerable. As OA entails high energy demands, particularly during the rapid juvenile growth phase, food supply may play a key role in the response of marine organisms to OA. We experimentally evaluated the role of food supply in modulating physiological responses and biomineralization processes in juveniles of the Chilean scallop, Argopecten purpuratus, that were exposed to control (pH ~ 8.0) and low pH (pH ~ 7.6) conditions using three food supply treatments (high, intermediate, and low). We found that pH and food levels had additive effects on the physiological response of the juvenile scallops. Metabolic rates, shell growth, net calcification, and ingestion rates increased significantly at low pH conditions, independent of food. These physiological responses increased significantly in organisms exposed to intermediate and high levels of food supply. Hence, food supply seems to play a major role modulating organismal response by providing the energetic means to bolster the physiological response of OA stress. On the contrary, the relative expression of chitin synthase, a functional molecule for biomineralization, increased significantly in scallops exposed to low food supply and low pH, which resulted in a thicker periostracum enriched with chitin polysaccharides. Under reduced food and low pH conditions, the adaptive organismal response was to trade-off growth for the expression of biomineralization molecules and altering of the organic composition of shell periostracum, suggesting that the future performance of these calcifiers will depend on the trajectories of both OA and food supply. Thus, incorporating a suite of traits and multiple stressors in future studies of the adaptive organismal response may provide key insights on OA impacts on marine calcifiers.
Publisher: Public Library of Science (PLoS)
Date: 05-08-2013
Publisher: Wiley
Date: 05-2022
DOI: 10.1002/ECE3.8888
Abstract: The study of sister species that occur in parapatry around biogeographic transition zones can help understand the evolutionary processes that underlie the changes in species composition across biogeographic transition zones. The South Eastern Pacific (SEP) coast is a highly productive coastal system that exhibits a broad biogeographic transition zone around 30–35°S. Here, we present a comparative genome‐wide analysis of the sister species Scurria viridula and Scurria zebrina , that occur in parapatry and whose poleward and equatorward range edges intersect in the 30–35°S SEP biogeographic transition zone. We s led 118 specimens sourced from nine sites from Tocopilla (22°S) to Chiloé (41°S) including one site where both species overlap and analyzed over 8000 biallelic single nucleotide polymorphisms. We found evidence of hybridization between these species in the contact zone and found significant but contrasting population structures for both species. Our results indicate that the genetic structure in S . viridula , which is currently expanding its range poleward, follows a simple isolation by distance model with no traces of natural selection (no evidence of outlier loci). In contrast, S . zebrina , which has its equatorward range edge at the transition zone, displayed a pronounced genetic break approximately at 32–34°S, along a region of marked environmental heterogeneity in association with a semi‐permanent coastal upwelling regime. For S . zebrina we also found 43 outlier loci associated with this genetic break, with a significant proportion of them clustering in a single linkage group. This marked difference in the presence of outlier loci between species suggests that they could be responding differently to local environmental challenges found at their overlapping geographic range edges, thus providing important new insights about genomic changes around biogeographic transition zones in sister species and the forces that shape genetic ersity in intertidal marine species.
No related grants have been discovered for Marco Lardies.