scholarly journals A Limpet’s Legacy: Carry-Over Effects across Life Stages and Generations Caused by Global Change Stressors

2021 ◽  
Author(s):  
◽  
Gustav Kessel

<p>Global change is increasingly impacting coastal marine systems. Organisms inhabiting the intertidal zone may be especially vulnerable to additional anthropogenic influences, which augment the naturally stressful, highly variable conditions to which they are already subjected and may lead to the manifestation of artificially severe carry-over effects (COEs). In marine invertebrates with complex life histories, COEs can occur between life stages, when the conditions experienced by one stage influence the characteristics or performance of the next, as well as trans-generationally, in which case the environment experienced by a parental generation affects offspring. Most of the existing literature surrounding COEs focuses only on those between life stages or generations, seldom both simultaneously, and do so with the implementation of only a single stressor. In nature however, organisms may be affected by both forms of COE, since the presence of one does not preclude the other, and are invariably subjected to multiple co-occurring stressors that can interact in complex ways. Consequently, how trans-generational COEs might impact the propagation of stress through offspring life stages remains unclear, and how these processes operate in a global change context is little understood. It was here aimed to elucidate the role of COEs under ongoing global change by addressing these common literature imitations and taking the novel approach of examining how the effects of multiple, global change-associated stressors carry-over from a parental generation through their offspring’s life stages in order to provide a more realistic representation of the conditions under which COEs manifest in the field.  This was done using Siphonaria australis, an intertidal pulmonate limpet that deposits benthic egg masses, from which hatch planktonic veliger larvae. Adult S. australis were subjected to one of four treatments for 4h/day over four weeks to induce trans-generational COEs: a no-stress control, a pollution treatment with added copper (5.0μg/L), a “climate change” treatment with elevated temperature (25°C) and UVR (1.7W/m2), and a full global change treatment incorporating all three stressors. At the end of this period, the egg masses laid under each of these adult treatments were subjected to further experimentation for two weeks by being redistributed among the same four treatments again, so as to produce 16 unique treatment histories of adult-to-egg mass stress. Of these, 11 provided successfully hatching larvae, which were reared and observed for COEs between life stages (from egg to larva) under ambient conditions (ie. no added stressors) for 27 days.  In adult S. australis survivor size, the size of egg masses laid and the size of individual eggs varied in complex ways over time and across treatments, while the number of survivors was unaffected by stress. Egg masses were unaffected in terms of hatching time but displayed strong responses to parental and developmental stress exposure through hatching success, and the percentage of viable eggs per egg mass, with the latter clearly declining according to adult treatment severity and both showing trans-generational COEs. Larval characteristics were extremely varied across treatment histories and highly context-dependent as hatching size, size reached by 27 days, growth rate, and size at death all showed evidence of COEs between generations and life stages, as well as interaction between both types of COE, with the number of survivors again being the only unaffected response variable. Overall, trans-generational COEs were slightly more common than those between life stages.  These results show that both forms of COE, each triggered by exposure to multiple stressors in progenitors and developmental stages, interact to form highly context-dependent legacies of mostly impaired performance in S. australis larvae. This implies that COEs may become more prominent with worsening stressors in the future and suggests that the role of COEs in the persistence of marine invertebrates under ongoing global change may so far have been underestimated by the existing literature.</p>

2021 ◽  
Author(s):  
◽  
Gustav Kessel

<p>Global change is increasingly impacting coastal marine systems. Organisms inhabiting the intertidal zone may be especially vulnerable to additional anthropogenic influences, which augment the naturally stressful, highly variable conditions to which they are already subjected and may lead to the manifestation of artificially severe carry-over effects (COEs). In marine invertebrates with complex life histories, COEs can occur between life stages, when the conditions experienced by one stage influence the characteristics or performance of the next, as well as trans-generationally, in which case the environment experienced by a parental generation affects offspring. Most of the existing literature surrounding COEs focuses only on those between life stages or generations, seldom both simultaneously, and do so with the implementation of only a single stressor. In nature however, organisms may be affected by both forms of COE, since the presence of one does not preclude the other, and are invariably subjected to multiple co-occurring stressors that can interact in complex ways. Consequently, how trans-generational COEs might impact the propagation of stress through offspring life stages remains unclear, and how these processes operate in a global change context is little understood. It was here aimed to elucidate the role of COEs under ongoing global change by addressing these common literature imitations and taking the novel approach of examining how the effects of multiple, global change-associated stressors carry-over from a parental generation through their offspring’s life stages in order to provide a more realistic representation of the conditions under which COEs manifest in the field.  This was done using Siphonaria australis, an intertidal pulmonate limpet that deposits benthic egg masses, from which hatch planktonic veliger larvae. Adult S. australis were subjected to one of four treatments for 4h/day over four weeks to induce trans-generational COEs: a no-stress control, a pollution treatment with added copper (5.0μg/L), a “climate change” treatment with elevated temperature (25°C) and UVR (1.7W/m2), and a full global change treatment incorporating all three stressors. At the end of this period, the egg masses laid under each of these adult treatments were subjected to further experimentation for two weeks by being redistributed among the same four treatments again, so as to produce 16 unique treatment histories of adult-to-egg mass stress. Of these, 11 provided successfully hatching larvae, which were reared and observed for COEs between life stages (from egg to larva) under ambient conditions (ie. no added stressors) for 27 days.  In adult S. australis survivor size, the size of egg masses laid and the size of individual eggs varied in complex ways over time and across treatments, while the number of survivors was unaffected by stress. Egg masses were unaffected in terms of hatching time but displayed strong responses to parental and developmental stress exposure through hatching success, and the percentage of viable eggs per egg mass, with the latter clearly declining according to adult treatment severity and both showing trans-generational COEs. Larval characteristics were extremely varied across treatment histories and highly context-dependent as hatching size, size reached by 27 days, growth rate, and size at death all showed evidence of COEs between generations and life stages, as well as interaction between both types of COE, with the number of survivors again being the only unaffected response variable. Overall, trans-generational COEs were slightly more common than those between life stages.  These results show that both forms of COE, each triggered by exposure to multiple stressors in progenitors and developmental stages, interact to form highly context-dependent legacies of mostly impaired performance in S. australis larvae. This implies that COEs may become more prominent with worsening stressors in the future and suggests that the role of COEs in the persistence of marine invertebrates under ongoing global change may so far have been underestimated by the existing literature.</p>


2021 ◽  
Author(s):  
◽  
Jeannine Fischer

<p>Salinity, temperature and ultraviolet-B (UV-B) radiation are common environmental stressors in coastal habitats. These stressors are likely to increase in intensity due to the effects of climate change and can have important impacts on population and community dynamics for early development in gastropods that deposit egg masses on rocky shores. The aim of this study was to identify the effects of single and multiple stressors on the development of intertidal and shallow subtidal gastropods with encapsulated embryos. In manipulative experiments I exposed egg masses of the gastropod species Siphonaria australis, Ercolania felina, Pleurobranchaea maculata, Aplysia juliana and Doris wellingtonensis to realistic levels of either salinity, temperature or UV-B radiation, or to a combination of stressors, for different lengths of time. Embryos were then subjected to the most stressful levels of each stressor at either early or late stages of development and at different days of embryonic development. Further, egg masses were exposed to sublethal salinity, temperature and UV-B radiation stress simultaneously, simulating tide pool conditions on a warm sunny summer day. Larvae hatching from stressed and unstressed egg masses were subsequently periodically subjected to increased temperature and UV-B radiation and examined over 10 days to detect possible carry-over effects of exposure to stress in the egg mass. The results revealed that for individual stressors, low salinity (20‰), high temperature (25°C) and high UV-B (1.7 W m ⁻ ² s ⁻ ¹, i.e. a level similar to a sunny NZ summer day) all caused the highest embryonic mortality. The response to stressors was species-specific but overall the intertidal species had lower embryonic mortality than the subtidal species. Generally, chronic exposure had higher impacts on the development of embryos than periodic exposure and early embryonic development stages were most vulnerable to stress. UV-B radiation had particularly damaging effects on embryonic and larval stages for the intertidal pulmonate limpet Siphonaria australis. Further, multiple stressors had synergistic effects and caused high embryonic mortality in the egg mass as well as impacting on the vulnerability of larvae to stressors. This study revealed that stress experienced during embryonic stages can result in sub-lethal damage that increases vulnerability to temperature and decreases vulnerability to UV-B radiation experienced in the larval stage. In total, my results suggest that (1) the effects of different environmental stressors on early development of intertidal and subtidal gastropods are complex and depend on the intensity, duration and time of stress, and are generally species-specific; (2) multiple stressors can act synergistically to affect early development and (3) sublethal exposure to stress in the egg mass can have negative carry-over effects on later larval stages.</p>


2021 ◽  
Author(s):  
◽  
Jeannine Fischer

<p>Salinity, temperature and ultraviolet-B (UV-B) radiation are common environmental stressors in coastal habitats. These stressors are likely to increase in intensity due to the effects of climate change and can have important impacts on population and community dynamics for early development in gastropods that deposit egg masses on rocky shores. The aim of this study was to identify the effects of single and multiple stressors on the development of intertidal and shallow subtidal gastropods with encapsulated embryos. In manipulative experiments I exposed egg masses of the gastropod species Siphonaria australis, Ercolania felina, Pleurobranchaea maculata, Aplysia juliana and Doris wellingtonensis to realistic levels of either salinity, temperature or UV-B radiation, or to a combination of stressors, for different lengths of time. Embryos were then subjected to the most stressful levels of each stressor at either early or late stages of development and at different days of embryonic development. Further, egg masses were exposed to sublethal salinity, temperature and UV-B radiation stress simultaneously, simulating tide pool conditions on a warm sunny summer day. Larvae hatching from stressed and unstressed egg masses were subsequently periodically subjected to increased temperature and UV-B radiation and examined over 10 days to detect possible carry-over effects of exposure to stress in the egg mass. The results revealed that for individual stressors, low salinity (20‰), high temperature (25°C) and high UV-B (1.7 W m ⁻ ² s ⁻ ¹, i.e. a level similar to a sunny NZ summer day) all caused the highest embryonic mortality. The response to stressors was species-specific but overall the intertidal species had lower embryonic mortality than the subtidal species. Generally, chronic exposure had higher impacts on the development of embryos than periodic exposure and early embryonic development stages were most vulnerable to stress. UV-B radiation had particularly damaging effects on embryonic and larval stages for the intertidal pulmonate limpet Siphonaria australis. Further, multiple stressors had synergistic effects and caused high embryonic mortality in the egg mass as well as impacting on the vulnerability of larvae to stressors. This study revealed that stress experienced during embryonic stages can result in sub-lethal damage that increases vulnerability to temperature and decreases vulnerability to UV-B radiation experienced in the larval stage. In total, my results suggest that (1) the effects of different environmental stressors on early development of intertidal and subtidal gastropods are complex and depend on the intensity, duration and time of stress, and are generally species-specific; (2) multiple stressors can act synergistically to affect early development and (3) sublethal exposure to stress in the egg mass can have negative carry-over effects on later larval stages.</p>


2018 ◽  
Vol 285 (1879) ◽  
pp. 20180285 ◽  
Author(s):  
J. Côte ◽  
A. Boniface ◽  
S. Blanchet ◽  
A. P. Hendry ◽  
J. Gasparini ◽  
...  

The role of parasites in shaping melanin-based colour polymorphism, and the consequences of colour polymorphism for disease resistance, remain debated. Here we review recent evidence of the links between melanin-based coloration and the behavioural and immunological defences of vertebrates against their parasites. First we propose that (1) differences between colour morphs can result in variable exposure to parasites, either directly (certain colours might be more or less attractive to parasites) or indirectly (variations in behaviour and encounter probability). Once infected, we propose that (2) immune variation between differently coloured individuals might result in different abilities to cope with parasite infection. We then discuss (3) how these different abilities could translate into variable sexual and natural selection in environments varying in parasite pressure. Finally, we address (4) the potential role of parasites in the maintenance of melanin-based colour polymorphism, especially in the context of global change and multiple stressors in human-altered environments. Because global change will probably affect both coloration and the spread of parasitic diseases in the decades to come, future studies should take into account melanin-based coloration to better predict the evolutionary responses of animals to changing disease risk in human-altered environments.


2014 ◽  
Vol 45 (3) ◽  
pp. 153-163 ◽  
Author(s):  
Sanne Nauts ◽  
Oliver Langner ◽  
Inge Huijsmans ◽  
Roos Vonk ◽  
Daniël H. J. Wigboldus

Asch’s seminal research on “Forming Impressions of Personality” (1946) has widely been cited as providing evidence for a primacy-of-warmth effect, suggesting that warmth-related judgments have a stronger influence on impressions of personality than competence-related judgments (e.g., Fiske, Cuddy, & Glick, 2007 ; Wojciszke, 2005 ). Because this effect does not fit with Asch’s Gestalt-view on impression formation and does not readily follow from the data presented in his original paper, the goal of the present study was to critically examine and replicate the studies of Asch’s paper that are most relevant to the primacy-of-warmth effect. We found no evidence for a primacy-of-warmth effect. Instead, the role of warmth was highly context-dependent, and competence was at least as important in shaping impressions as warmth.


Author(s):  
Charlotte Scott

Beginning with an exploration of the role of the child in the cultural imagination, Chapter 1 establishes the formative and revealing ways in which societies identify themselves in relation to how they treat their children. Focusing on Shakespeare and the early modern period, Chapter 1 sets out to determine the emotional, symbolic, and political registers through which children are depicted and discussed. Attending to the different life stages and representations of the child on stage, this chapter sets out the terms of the book’s enquiry: what role do children play in Shakespeare’s plays; how do we recognize them as such—age, status, parental dynamic—and what are the effects of their presence? This chapter focuses on how the early moderns understood the child, as a symbolic figure, a life stage, a form of obligation, a profound bond, and an image of servitude.


2019 ◽  
Vol 33 (2) ◽  
pp. 370-375 ◽  
Author(s):  
Camilla de Carvalho de Brito ◽  
Washington Soares Ferreira-Júnior ◽  
Ulysses Paulino Albuquerque ◽  
Marcelo Alves Ramos ◽  
Taline Cristina da Silva ◽  
...  

1997 ◽  
Vol 75 (6) ◽  
pp. 773-789 ◽  
Author(s):  
Eric J. Dumdei ◽  
Julia Kubanek ◽  
John E. Coleman ◽  
Jana Pika ◽  
Raymond J. Andersen ◽  
...  

Chemical investigations of Cadlinaluteomarginata skin extracts, egg masses, and dietary sponges have led to the identification of the novel terpenoids cadlinaldehyde (30), spongian 32, seco-spongian 35, 20-acetoxy-12-marginatone (38), and lutenolide (39) from the nudibranch skin extracts, the new drimane sesquiterpenoid 1α,2α-diacetoxyalbicanyl acetate (40) from the nudibranch's egg mass, and the new sesquiterpenoids O-methyl-9-oxofurodysininlactone (47), 2-oxomicro-cionin-2-lactone (48), and O-methyl-2-oxomicrocionin-2-lactone (49), from the dietary sponge Pleraplysilla sp. The known terpenoids furodysinin (1), furodysin (16), marginatafuran (21), and 9,11-dihydrogracillin A (37), which have been frequently isolated from C. luteomarginata skin extracts, were found for the first time in extracts of the dietary sponges Pleraplysilla sp. and Aplysilla sp. One of the new terpenoids, cadlinaldehyde (30), has an unprecedented degraded sesterterpenoid skeleton. Keywords: nudibranch, sponge, terpenoids, structure elucidation.


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