Climate change and polar marine invertebrates: life-history responses in a warmer, high CO2 world.
Polar marine invertebrates serve as bellwethers for species vulnerabilities in the face of changing climate at high latitudes of the Earth. Ocean acidification, warming/heatwaves, freshening, sea ice retreat and productivity change are challenges for polar species. Adaptations to life in cold water with intensely seasonal productivity has shaped species traits at both poles. Polar species have life histories often characterised as K-strategist or K-selected (e.g. slow growth and development, larval hypometabolism) that make them sensitive to climate stress and altered seasonal productivity. Moderate warming results in faster development and can have positive effects on development, up to a limit. However, ocean acidification can retard development, impair skeletogenesis and result in smaller larvae. Given the fast pace of warming, data on the thermal tolerance of larvae from diverse species is urgently needed, as well as knowledge of adaptive responses to ocean acidification and changes to sea ice and productivity. Predicted productivity increase would benefit energy-limited reproduction and development, while sea ice loss negatively impacts species with reproduction that directly or indirectly depend on this habitat. It is critical to understand the interactive effects between warming, acidification and other stressors. Polar specialists cannot migrate, making them susceptible to competition and extinction from range-extending subpolar species. The borealisation and australisation of Arctic and Antarctic ecosystems, respectively, is underway as these regions become more hospitable for the larval and adult life-history stages of lower-latitude species. Differences in biogeography and pace of change point to different prospects for Arctic and Antarctic communities. In this Commentary, we hypothesise outcomes for polar species based on life history traits and sensitivity to climate change and suggest research avenues to test our predictions.
Byrne M
，Lamare MD
《-》
High vulnerability of the endemic Southern Ocean snail Neobuccinum eatoni (Buccinidae) to critical projected oceanographic changes.
Climate change is projected to substantially alter the Southern Ocean's physical and chemical properties, thereby impacting its marine ecosystems and species, particularly those in Antarctic and sub-Antarctic regions. This study focuses on Neobuccinum eatoni, a polar marine 'true whelk' endemic to these regions, utilizing 166 spatially independent occurrence data records to model potential distribution shifts under future climate scenarios. Employing Species Distribution Models (SDMs) on spatially cross-validated occurrences, we achieved high predictive accuracy, identifying "sea water salinity range" at mean bottom depth as the most significant predictor of habitat preferences. Additionally, dissolved iron (minimum), ocean temperature (range), and pH (long-term maximum) emerged as critical factors influencing the species' modeled distribution. By 2050, future projections under the SSP2-4.5 scenario predict an eastward expansion, particularly in the Antarctic Peninsula, the Scotia Arc and the Weddell Sea, with an expansion in the latter region also predicted under the SSP5-8.5 scenario. However, in both scenarios, a reduction in habitat suitability is expected in certain sectors around the Antarctic continent and the Kerguelen Archipelago. By 2100, under the moderate emissions scenario (SSP2-4.5), the species is projected to move to deeper areas and lower latitudes, with notable expansions in the Weddell Sea and in the Southern Ocean surrounding the Kerguelen Archipelago. However, under the SSP5-8.5 scenario, expansion is projected in the Weddell Sea and reductions in Antarctic and subantarctic regions. This study highlights the critical influence of changing salinity on N. eatoni's distribution, predicting a significant habitat reduction under high CO2 emissions scenarios (SSP5-8.5). The findings underscore the urgent need for focused research on the vulnerability of endemic marine invertebrates to develop effective conservation strategies in the face of rapid climatic changes.
González R
，Pertierra LR
，Guerrero PC
，Díaz A
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《Scientific Reports》
Valley fever under a changing climate in the United States.
This review summarizes studies on the relationships between climate change and Valley Fever (VF), also termed Coccidioidomycosis, a potentially fatal upper-respiratory fungal infection caused by the pathogenic fungi, C. immitis or C. posadasii. The intensified onset of climate change has caused frequencies and possibly intensities of natural hazard events like dust storms and drought to increase, which has been correlated with greater prevalence of VF. These events, followed by changes in patterns of precipitation, not only pick up dust and spread it throughout the air, but also boost the growth and spread of Coccidioides. In California alone, cases of VF have increased fivefold from 2001 to 2021, and are expected to continue to increase. From 1999 to 2019, there was an average of 200 deaths per year caused by VF in the United States. The number of deaths caused by VF fluctuates year to year, but because more infections are predicted to occur due to a changing climate, deaths are expected to rise; thus, the rising prevalence of the disease is becoming a larger focus of the scientific community and poses an increased threat to public health. By reviewing recent and past studies on Coccidioidomycosis and its relationships with climate factors, we categorize future impacts of this disease on the United States, and highlight areas that need more study. Factors affecting the incidence of VF, such as modes of dispersal and the optimum environment for Coccidioides growth, that could potentially increase its prevalence as weather patterns change are discussed and how the endemic regions could be affected are assessed. In general, regions of the United States, including California and Arizona, where VF is endemic, are expanding and incidences of VF are increasing in those areas. The surrounding southern states, including Nevada, New Mexico, Utah, and Texas, are experiencing similar changes. In addition, the entire endemic region of the United States is predicted to spread northward as drought is prolonged and temperatures steadily increase. The findings from the keyword search from eight databases indicate that more studies on VF and its relation to dust and climate are needed especially for endemic states like Nevada that are currently not adequately studied. Overall, results of this survey summarize mechanisms and climate factors that might drive spread of VF and describes trends of incidence of VF in endemic states and predicted likely trends that might occur under a changing climate. Through reviewing recent and past studies of Coccidioidomycosis and its relationships with climate factors, future impacts of this disease have been categorized and speculated on effects it might have on the United States. Better understanding of how climate factors affect VF as well as identifying regions that require more research could inform both environmental managers and medical professionals with the resources needed to make more accurate predictions, design better mitigation strategies, send timely warnings, and protect public health. Shortened version This review explores how climate change affects Valley Fever (VF), a dangerous fungal infection caused by C. immitis or C. posadasii. Climate change has increased natural hazard events such as dust storms and droughts, which have caused the spread of VF. Cases of the disease have increased fivefold between 2001 and 2021 in California alone, and it poses an increasing threat to public health. The review summarizes mechanisms that drive the spread of VF and highlights trends in endemic states under a changing climate. It recommends more studies on VF and its relation to dust and climate, especially for states like Nevada. Identifying regions that require more research can help make more accurate predictions, design better mitigation strategies, send timely warnings, and protect public health.
Howard MH
，Sayes CM
，Giesy JP
，Li Y
... -
《-》
Habitat dimensionality and feeding strategies but not temperature as determinants of body size-trophic structure relationship in a marine food web.
Disentangling the determinants of trophic structure is central to ecology. The capacity to capture subjugate and consume a prey (i.e. gape limitation) is a relevant limitation to acquire energy for most organisms, especially those in smaller size ranges. This generates a size hierarchy of trophic positions in which large organisms consume small ones. Body size is tightly correlated to gape limitation and explains a large fraction of variance in the body size-trophic position relationship. However, a considerable fraction of variance still remains to be explained. Consumer search space dimensionality (2D or 3D) and feeding strategies, temperature and the size structure of primary producers can alter the trophic structure, but tests based on information from natural food webs are scarce. We generated specific predictions about the body size trophic position relationship and evaluated them using information from a subtropical South Atlantic coastal marine ecosystem: benthic realm (2D, rocky shore and sandy beach) and the pelagic realm (3D). We characterized this marine coastal food web based on stable isotopes of carbon and nitrogen from 256 samples from primary producers (macroalgae and phytoplankton) to large predators (sand shark) in summer and winter. Consumer body size encompassed six orders of magnitude in weight from 10-2 to 6 × 104 g. Isotopic signal corresponded to an integration of carbon sources from basal consumers to top predators. The body size-trophic position relationship showed a linear positive association with different slopes for the benthic and pelagic environments. This implies a smaller predator prey size ratio for pelagic (3D) with respect to benthic consumers (2D) as theoretically expected. No seasonal differences were found in slopes and most of the overall variance in benthic environments was largely explained by feeding strategies of the different taxonomic groups. We provide an integrated evaluation on the role of body size, consumer search space and feeding strategy to understand the determinants of trophic position. Results demonstrate that integrating gape limitation hypothesis, the dimensionality of consumer search space and feeding strategies into a formal robust framework to understand trophic structure is feasible even in complex natural ecosystems.
Leoni V
，Franco-Trecu V
，Scarabino F
，Sampognaro L
，Rodríguez-Graña L
，Segura AM
... -
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ResearchGate
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钛学术
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