Value-based routing of delayed intentions into brain-based versus external memory stores

Individuals have the option of remembering delayed intentions by storing them in internal memory or offloading them to an external store such as a diary or smartphone alert. How do we route intentions to the appropriate store, and what are the consequences of this? We report three experiments (two preregistered) investigating the role of value. In Experiment 1, participants preferentially offloaded high-value intentions to the external environment. This improved memory for both high- and low-value content. Experiment 2 replicated the low-value memory enhancement even when only high-value intentions were offloaded. This provides evidence for a cognitive spillover effect: When high-value content is offloaded, internal memory becomes reallocated to low-value content instead. Experiment 3 confirmed a theoretical prediction of this account: participants had superior memory for low- than high-value content when the external store was removed. These results imply that value-based offloading can lead to a cognitive spillover effect from high- to low-value content, similar to the automatic allocation of "spare" capacity that has been proposed in the domain of visual attention. Individuals prioritize high-value information for external memory; consequently, they can be left with predominantly low-value information if it fails. (PsycInfo Database Record (c) 2022 APA, all rights reserved)

Elevated temperature, but not decreased pH, impairs reproduction in a temperate fish.

Fish reproductive success is linked to the ability of couples to mate and produce clutches that successfully hatch. Environmental stressors like high temperature and low pH can jeopardize this energetically costly process. In this study, exposure to high temperature and low pH was tested on a marine temperate species, Gobiusculus flavescens, to evaluate effects on reproductive performance. Breeding pairs were assigned to different temperatures (+ 0 °C, + 3 °C relative to in situ temperature) and pH levels (8.0, 7.6), in a cross-factorial design for a 3-month period. Reproduction activity, success, and paternal investment were measured throughout the exposure period. Results show reproduction is impaired by elevated temperature, while low pH had little impact. Breeding pairs under high temperature had 3% to 10% hatching success, up to 30% less eggs and eggs up to 20% smaller. Although paternal investment was not affected by tested parameters, males of breeding pairs exposed to elevated temperature had smaller gonadosomatic indexes, which might indicate a lack of investment in the reproductive process. Overall, results show that elevated temperature, expected more frequently in the near future, as a consequence of global warming, may impair key processes like reproduction in temperate fish, with potential consequences for fitness and population replenishment.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Potential for acclimation of banded-dye murex, Hexaplex trunculus (Linnaeus, 1758) after long-term exposure to low pH

Previous work on ocean acidification highlighted contrasting response between marine species and population. This so-called species-specific response was hypothesized to be partly a consequence of local adaptation to the present range of natural variability in the carbonate chemistry. Under that hypothesis, species tolerance threshold should be correlated to its environmental pH niche. This paper aims to evaluate shell growth rate of Hexaplex trunculus, an important predatory gastropod in benthic communities of Mali Ston Bay. A long-term experiment (310 days) was designed to test a range of pH treatments covering present and future pH levels relevant in the context of future ocean acidification (7.95-7.22 pHT) at the sampling site. Sex had an effect on the shell growth rate irrespective of pH, and was only significant after 236 days. As growth rate in all pH treatments followed seasonal patterns correlating to changes in seawater temperature, the data were divided into 3 time periods. A positive relationship between shell growth rate (SGR, mm day-1) and pH was observed for the period 1-59 days (temperature ranging between 26.5 & 18.8 °C), whereas SGR decreased significantly with pH for the following period (60-236 days, temperature ranging between 20.6 & 8.5 °C). After 236 days (temperature ranging between 27.5 & 14.1 °C), there was no significant difference in SGR among pH. Similar temperature was experienced between the first and third period and the difference in response could be explained as a consequence of an acute negative response versus a longer exposure indicating possible potential for acclimation. Our results highlight the modulating effect of temperature and the importance of long-term experiments to better assess impacts of ocean acidification on marine organisms

Near-future level of CO2-driven ocean acidification radically affects larval survival and development in the brittlestar Ophiothrix fragilis

The world's oceans are slowly becoming more acidic. In the last 150 yr, the pH of the oceans has dropped by similar to 0.1 units, which is equivalent to a 25 % increase in acidity. Modelling predicts the pH of the oceans to fall by 0.2 to 0.4 units by the year 2100. These changes will have significant effects on marine organisms, especially those with calcareous skeletons such as echinoderms. Little is known about the possible long-term impact of predicted pH changes on marine invertebrate larval development. Here we predict the consequences of increased CO2 (corresponding to pH drops of 0.2 and 0.4 units) on the larval development of the brittlestar Ophiothrix fragilis, which is a keystone species occurring in high densities and stable populations throughout the shelf seas of northwestern Europe (eastern Atlantic). Acidification by 0.2 units induced 100 % larval mortality within 8 d while control larvae showed 70 % survival over the same period. Exposure to low pH also resulted in a temporal decrease in larval size as well as abnormal development and skeletogenesis (abnormalities, asymmetry, altered skeletal proportions). If oceans continue to acidify as expected, ecosystems of the Atlantic dominated by this keystone species will be seriously threatened with major changes in many key benthic and pelagic ecosystems. Thus, it may be useful to monitor O. fragilis populations and initiate conservation if needed

Ocean Acidification Accelerates Reef Bioerosion

In the recent discussion how biotic systems may react to ocean acidification caused by the rapid rise in carbon dioxide partial pressure (pCO2) in the marine realm, substantial research is devoted to calcifiers such as stony corals. The antagonistic process – biologically induced carbonate dissolution via bioerosion – has largely been neglected. Unlike skeletal growth, we expect bioerosion by chemical means to be facilitated in a high-CO2 world. This study focuses on one of the most detrimental bioeroders, the sponge Cliona orientalis, which attacks and kills live corals on Australia’s Great Barrier Reef. Experimental exposure to lowered and elevated levels of pCO2 confirms a significant enforcement of the sponges’ bioerosion capacity with increasing pCO2 under more acidic conditions. Considering the substantial contribution of sponges to carbonate bioerosion, this finding implies that tropical reef ecosystems are facing the combined effects of weakened coral calcification and accelerated bioerosion, resulting in critical pressure on the dynamic balance between biogenic carbonate build-up and degradation

Refining the Ciona intestinalis Model of Central Nervous System Regeneration

BACKGROUND: New, practical models of central nervous system regeneration are required and should provide molecular tools and resources. We focus here on the tunicate Ciona intestinalis, which has the capacity to regenerate nerves and a complete adult central nervous system, a capacity unusual in the chordate phylum. We investigated the timing and sequence of events during nervous system regeneration in this organism. METHODOLOGY/PRINCIPAL FINDINGS: We developed techniques for reproducible ablations and for imaging live cellular events in tissue explants. Based on live observations of more than 100 regenerating animals, we subdivided the regeneration process into four stages. Regeneration was functional, as shown by the sequential recovery of reflexes that established new criteria for defining regeneration rates. We used transgenic animals and labeled nucleotide analogs to describe in detail the early cellular events at the tip of the regenerating nerves and the first appearance of the new adult ganglion anlage. CONCLUSIONS/SIGNIFICANCE: The rate of regeneration was found to be negatively correlated with adult size. New neural structures were derived from the anterior and posterior nerve endings. A blastemal structure was implicated in the formation of new neural cells. This work demonstrates that Ciona intestinalis is as a useful system for studies on regeneration of the brain, brain-associated organs and nerves

Genomic characterization of the evolutionary potential of the sea urchin Strongylocentrotus droebachiensis facing ocean acidification

Ocean acidification (OA) is increasing due to anthropogenic CO2 emissions and poses a threat to marine species and communities worldwide. To better project the effects of acidification on organisms’ health and persistence, an understanding is needed of the 1) mechanisms underlying developmental and physiological tolerance and 2) potential populations have for rapid evolutionary adaptation. This is especially challenging in nonmodel species where targeted assays of metabolism and stress physiology may not be available or economical for large-scale assessments of genetic constraints. We used mRNA sequencing and a quantitative genetics breeding design to study mechanisms underlying genetic variability and tolerance to decreased seawater pH (-0.4 pH units) in larvae of the sea urchin Strongylocentrotus droebachiensis. We used a gene ontology-based approach to integrate expression profiles into indirect measures of cellular and biochemical traits underlying variation in larval performance (i.e., growth rates). Molecular responses to OA were complex, involving changes to several functions such as growth rates, cell division, metabolism, and immune activities. Surprisingly, the magnitude of pH effects on molecular traits tended to be small relative to variation attributable to segregating functional genetic variation in this species. We discuss how the application of transcriptomics and quantitative genetics approaches across diverse species can enrich our understanding of the biological impacts of climate change

Ocean acidification increases the accumulation of toxic phenolic compounds across trophic levels

Increasing atmospheric CO2 concentrations are causing ocean acidification (OA), altering carbonate chemistry with consequences for marine organisms. Here we show that OA increases by 46–212% the production of phenolic compounds in phytoplankton grown under the elevated CO2 concentrations projected for the end of this century, compared with the ambient CO2 level. At the same time, mitochondrial respiration rate is enhanced under elevated CO2 concentrations by 130–160% in a single species or mixed phytoplankton assemblage. When fed with phytoplankton cells grown under OA, zooplankton assemblages have significantly higher phenolic compound content, by about 28–48%. The functional consequences of the increased accumulation of toxic phenolic compounds in primary and secondary producers have the potential to have profound consequences for marine ecosystem and seafood quality, with the possibility that fishery industries could be influenced as a result of progressive ocean change