Environmental Change
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2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Finn A. Viehberg ◽  
Andrew S. Medeiros ◽  
Birgit Plessen ◽  
Xiaowa Wang ◽  
Derek Muir ◽  
...  

AbstractHigh latitude freshwater ecosystems are sentinels of human activity and environmental change. The lakes and ponds that characterize Arctic landscapes have a low resilience to buffer variability in climate, especially with increasing global anthropogenic stressors in recent decades. Here, we show that a small freshwater pond in proximity of the archaeological site “Native Point” on Southampton Island (Nunavut, Arctic Canada) is a highly sensitive environmental recorder. The sediment analyses allowed for pinpointing the first arrival of Sadlermiut culture at Native Point to ~ 1250 CE, followed by a dietary shift likely in response to the onset of cooling in the region ~ 1400 CE. The influence of the Sadlermiut on the environment persisted long after the last of their population perished in 1903. Presently, the pond remains a distorted ecosystem that has experienced fundamental shifts in the benthic invertebrate assemblages and accumulated anthropogenic metals in the sediment. Our multi-proxy paleolimnological investigation using geochemical and biological indicators emphasizes that direct and indirect anthropogenic impacts have long-term environmental implications on high latitude ecosystems.


2021 ◽  
Author(s):  
Shannon Dee ◽  
Thomas DeCarlo ◽  
Ivan Lozic ◽  
Jake Neilsen ◽  
Nicola Browne

Abstract Bioerosion on turbid inshore reefs is expected to increase with global climate change reducing reef stability and accretionary potential. Most studies investigating bioerosion have focused on external grazers, such as parrotfish and urchins, whose biomass is more easily measured. Yet, cryptic endolithic bioeroders such as macroboring (worms, sponges and bivalves) and microboring taxa (fungus and algae) have the potential to be the dominant bioeroders, especially among inshore reef systems exposed to increased nutrient supply. We measured bioerosion rates of three bioeroder groups (microborers, macroborers, and grazers), and their response to environmental parameters (temperature, turbidity, light, chlorophyll a, salinity, pH) across two inshore reefs of north Western Australia. Total bioerosion rates were low (0.152 ± 0.012 kg m-1 yr-1) compared to average global rates, but were comparable to other inshore turbid reefs. Macroboring worms were the dominant source of bioerosion and displayed a significant negative relationship with temperature (r2= 0.24, P=0.008) and light (r2= 0.16, P=0.037). A global assessment of environmental influences on bioerosion further identified chlorophyll-a as a significant driver of macroboring (r2= 0.60, P=<0.001). Low bioerosion rates among marginal inshore reefs is encouraging as these reefs may be able to maintain a positive carbonate budget state despite lower coral cover and gross carbonate production rates. These data also highlight the necessity of reducing local impacts such as nutrient loads, which drive increases in chlorophyll a, to support marginal reef systems with climate change. Further, the development of empirical relationships that quantitatively link bioeroder activity and rates of environmental change will improve our ability to predict reef responses to environmental change, and better manage reefs into the future.


2021 ◽  
Author(s):  
David J. Meltzer

Over 15,000 years ago, a band of hunter-gatherers became the first people to set foot in the Americas. They soon found themselves in a world rich in plants and animals, but also a world still shivering itself out of the coldest depths of the Ice Age. The movement of those first Americans was one of the greatest journeys undertaken by ancient peoples. In this book, David Meltzer explores the world of Ice Age Americans, highlighting genetic, archaeological, and geological evidence that has revolutionized our understanding of their origins, antiquity, and adaptation to climate and environmental change. This fully updated edition integrates the most recent scientific discoveries, including the ancient genome revolution and human evolutionary and population history. Written for a broad audience, the book can serve as the primary text in courses on North American Archaeology, Ice Age Environments, and Human evolution and prehistory.


Author(s):  
Nicole Nova

Coronaviruses cause respiratory and digestive diseases in vertebrates. The recent pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2, is taking a heavy toll on society and planetary health, and illustrates the threat emerging coronaviruses can pose to the wellbeing of humans and other animals. Coronaviruses are constantly evolving, crossing host species barriers, and expanding their host range. In the last few decades, several novel coronaviruses have emerged in humans and domestic animals. Novel coronaviruses have also been discovered in captive wildlife or wild populations, raising conservation concerns. The evolution and emergence of novel viruses is enabled by frequent cross-species transmission. It is thus crucial to determine emerging coronaviruses’ potential for infecting different host species, and to identify the circumstances under which cross-species transmission occurs in order to mitigate the rate of disease emergence. Here, I review (broadly across several mammalian host species) up-to-date knowledge of host range and circumstances concerning reported cross-species transmission events of emerging coronaviruses in humans and common domestic mammals. All of these coronaviruses had similar host ranges, were closely related (indicative of rapid diversification and spread), and their emergence was likely associated with high-host-density environments facilitating multi-species interactions (e.g., shelters, farms, and markets) and the health or wellbeing of animals as end- and/or intermediate spillover hosts. Further research is needed to identify mechanisms of the cross-species transmission events that have ultimately led to a surge of emerging coronaviruses in multiple species in a relatively short period of time in a world undergoing rapid environmental change.


Author(s):  
Aiai Xu ◽  
Jie Liu ◽  
Zhiying Guo ◽  
Changkun Wang ◽  
Kai Pan ◽  
...  

It is critical to identify the assembly processes and determinants of soil microbial communities to better predict soil microbial responses to environmental change in arid and semiarid areas. Here, soils from 16 grassland-only, 9 paired grassland and farmland, and 16 farmland-only sites were collected across the central Inner Mongolia Plateau covering a steep environmental gradient. Through analyzing the paired samples, we discovered that land uses had strong effects on soil microbial communities, but weak effects on their assembly processes. For all samples, although no environmental variables were significantly correlated with the net relatedness index (NRI), both the nearest taxon index (NTI) and the β-nearest taxon index (βNTI) were most related to mean annual precipitation (MAP). With the increase of MAP, soil microbial taxa at the tips of the phylogenetic tree were more clustered, and the contribution of determinism increased. Determinism (48.6%), especially variable selection (46.3%), and stochasticity (51.4%) were almost equal in farmland, while stochasticity (75.0%) was dominant in grassland. Additionally, Mantel tests and redundancy analyses (RDA) revealed that the main determinants of soil microbial community structure were MAP in grassland, but mean annual temperature (MAT) in farmland. MAP and MAT were also good predictors of the community composition (the top 200 dominant OTUs) in grassland and farmland, respectively. Collectively, in arid and semiarid areas, soil microbial communities were more sensitive to environmental change in farmland than in grassland, and unlike the major impact of MAP on grassland microbial communities, MAT was the primary driver of farmland microbial communities. Importance As one of the most diverse organisms, soil microbes play indispensable roles in many ecological processes in arid and semiarid areas with limited macrofaunal and plant diversity, yet the mechanisms underpinning soil microbial community are not fully understood. In this study, soil microbial communities were investigated along a 500 km transect covering a steep environmental gradient across farmland and grassland in the areas. The results showed that precipitation was the main factor mediating the assembly processes. Determinism was more influential in farmland, and variable selection of farmland was twice that of grassland. Temperature mainly drove farmland microbial communities, while precipitation mainly affected grassland microbial communities. These findings provide new information about the assembly processes and determinants of soil microbial communities in arid and semiarid areas, consequently improving the predictability of the community dynamics, which have implications for sustaining soil microbial diversity and ecosystem functioning, particularly under global climate change conditions.


2021 ◽  
Author(s):  
Wanxiaojie Xie ◽  
Kimberley Bruce ◽  
Helen E. Farrell ◽  
Philip G. Stevenson

Herpesvirus genomes show abundant evidence of past recombination. Its functional importance is unknown. A key question is whether recombinant viruses can outpace the immunity induced by their parents to reach higher loads. We tested this by co-infecting mice with attenuated mutants of Murid Herpesvirus-4 (MuHV-4). Infection by the natural olfactory route routinely allowed mutant viruses to reconstitute wild-type genotypes and reach normal viral loads. Lung co-infections rescued much less well. Attenuated murine cytomegalovirus mutants similarly showed recombinational rescue via the nose but not the lungs. These infections spread similarly, so route-specific rescue implied that recombination occurred close to the olfactory entry site. Rescue of replication-deficient MuHV-4 confirmed this, showing that coinfection occurred in the first encountered olfactory cells. This worked even with asynchronous inoculation, implying that a defective virus can wait here for later rescue. Virions entering the nose get caught on respiratory mucus, which the respiratory epithelial cilia push back towards the olfactory surface. Early infection was correspondingly focussed on the anterior olfactory edge. Thus, by concentrating incoming infection into a small area, olfactory entry seems to promote functionally significant recombination. Importance All organisms depend on genetic diversity to cope with environmental change. Small viruses rely on frequent point mutations. This is harder for herpesviruses because they have larger genomes. Recombination provides another means of genetic optimization. Human herpesviruses often co-infect, and they show evidence of past recombination, but whether this is rare and incidental or functionally important is unknown. We showed that herpesviruses entering mice via the natural olfactory route meet reliably enough for recombination routinely to repair crippling mutations and restore normal viral loads. It appeared to occur in the first encountered olfactory cells and reflected a concentration of infection at the anterior olfactory edge. Thus, natural host entry incorporates a significant capacity for herpesvirus recombination.


Oikos ◽  
2021 ◽  
Author(s):  
Rachel L. Gunn ◽  
Ian R. Hartley ◽  
Adam C. Algar ◽  
Petri T. Niemelä ◽  
Sally A. Keith

2021 ◽  
Vol 224 (18) ◽  
Author(s):  
Shaun S. Killen ◽  
Emil A. F. Christensen ◽  
Daphne Cortese ◽  
Libor Závorka ◽  
Tommy Norin ◽  
...  

ABSTRACT Interest in the measurement of metabolic rates is growing rapidly, because of the importance of metabolism in advancing our understanding of organismal physiology, behaviour, evolution and responses to environmental change. The study of metabolism in aquatic animals is undergoing an especially pronounced expansion, with more researchers utilising intermittent-flow respirometry as a research tool than ever before. Aquatic respirometry measures the rate of oxygen uptake as a proxy for metabolic rate, and the intermittent-flow technique has numerous strengths for use with aquatic animals, allowing metabolic rate to be repeatedly estimated on individual animals over several hours or days and during exposure to various conditions or stimuli. There are, however, no published guidelines for the reporting of methodological details when using this method. Here, we provide the first guidelines for reporting intermittent-flow respirometry methods, in the form of a checklist of criteria that we consider to be the minimum required for the interpretation, evaluation and replication of experiments using intermittent-flow respirometry. Furthermore, using a survey of the existing literature, we show that there has been incomplete and inconsistent reporting of methods for intermittent-flow respirometry over the past few decades. Use of the provided checklist of required criteria by researchers when publishing their work should increase consistency of the reporting of methods for studies that use intermittent-flow respirometry. With the steep increase in studies using intermittent-flow respirometry, now is the ideal time to standardise reporting of methods, so that – in the future – data can be properly assessed by other scientists and conservationists.


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