An ancient, Antarctic-specific species complex: large divergences between multiple Antarctic lineages of the tardigrade genus Mesobiotus.

Antarctica has been isolated and progressively glaciated for over 30 million years, with only approximately 0.3 % of its area currently ice-free and capable of supporting terrestrial ecosystems. As a result, invertebrate populations have become isolated and fragmented, in some cases leading to speciation. Terrestrial invertebrate species currently found in Antarctica often show multi-million year, and even Gondwanan, heritage, with little evidence of recent colonisation. Mesobiotus is a globally distributed tardigrade genus. It has commonly been divided into two "groups", referred to as harmsworthi and furciger, with both groups currently considered cosmopolitan, with global reports including from both the Arctic and the Antarctic. However, some authors considered that Meb. furciger, as originally described, may represent an Antarctic-specific lineage. Using collections of tardigrades from across the Antarctic continent and publicly available sequences obtained from online databases, we use mitochondrial and nuclear ribosomal sequence data to clarify the relationships of Antarctic Mesobiotus species. Our analyses show that all Antarctic members belong to a single lineage, evolving separately from non-Antarctic representatives. Within this Antarctic lineage there are further deep divisions among geographic regions of the continent, consistent with the presence of a species complex. Based on our data confirming the deep divisions between this Antarctic lineage, which includes representatives of both groups, we recommend that the use of furciger and harmsworthi group terminology is now abandoned, as it leads to systematic and biogeographical confusion.

Evidence of altered fatty acid metabolism in dogs with naturally occurring valvular heart disease and congestive heart failure.

INTRODUCTION: Myxomatous mitral valve disease (MMVD) is the most common cardiac condition in adult dogs. The disease progresses over several years and affected dogs may develop congestive heart failure (HF). Research has shown that myocardial metabolism is altered in cardiac disease, leading to a reduction in ß-oxidation of fatty acids and an increased dependence upon glycolysis. OBJECTIVES: This study aimed to evaluate whether a shift in substrate use occurs in canine patients with MMVD; a naturally occurring model of human disease. METHODS: Client-owned dogs were longitudinally evaluated at a research clinic in London, UK and paired serum samples were selected from visits when patients were in ACVIM stage B1: asymptomatic disease without cardiomegaly, and stage C: HF. Samples were processed using ultra-performance liquid chromatography mass spectrometry and lipid profiles were compared using mixed effects models with false discovery rate adjustment. The effect of disease stage was evaluated with patient breed entered as a confounder. Features that significantly differed were screened for selection for annotation efforts using reference databases. RESULTS: Dogs in HF had altered concentrations of lipid species belonging to several classes previously associated with cardiovascular disease. Concentrations of certain acylcarnitines, phospholipids and sphingomyelins were increased after individuals had developed HF, whilst some ceramides and lysophosphatidylcholines decreased. CONCLUSIONS: The canine metabolome appears to change as MMVD progresses. Findings from this study suggest that in HF myocardial metabolism may be characterised by reduced ß-oxidation. This proposed explanation warrants further research.

Societal importance of Antarctic negative feedbacks on climate change: blue carbon gains from sea ice, ice shelf and glacier losses.

Diminishing prospects for environmental preservation under climate change are intensifying efforts to boost capture, storage and sequestration (long-term burial) of carbon. However, as Earth's biological carbon sinks also shrink, remediation has become a key part of the narrative for terrestrial ecosystems. In contrast, blue carbon on polar continental shelves have stronger pathways to sequestration and have increased with climate-forced marine ice losses-becoming the largest known natural negative feedback on climate change. Here we explore the size and complex dynamics of blue carbon gains with spatiotemporal changes in sea ice (60-100 MtCyear-1), ice shelves (4-40 MtCyear-1 = giant iceberg generation) and glacier retreat (< 1 MtCyear-1). Estimates suggest that, amongst these, reduced duration of seasonal sea ice is most important. Decreasing sea ice extent drives longer (not necessarily larger biomass) smaller cell-sized phytoplankton blooms, increasing growth of many primary consumers and benthic carbon storage-where sequestration chances are maximal. However, sea ice losses also create positive feedbacks in shallow waters through increased iceberg movement and scouring of benthos. Unlike loss of sea ice, which enhances existing sinks, ice shelf losses generate brand new carbon sinks both where giant icebergs were, and in their wake. These also generate small positive feedbacks from scouring, minimised by repeat scouring at biodiversity hotspots. Blue carbon change from glacier retreat has been least well quantified, and although emerging fjords are small areas, they have high storage-sequestration conversion efficiencies, whilst blue carbon in polar waters faces many diverse and complex stressors. The identity of these are known (e.g. fishing, warming, ocean acidification, non-indigenous species and plastic pollution) but not their magnitude of impact. In order to mediate multiple stressors, research should focus on wider verification of blue carbon gains, projecting future change, and the broader environmental and economic benefits to safeguard blue carbon ecosystems through law.

Marine plastics threaten giant Atlantic Marine Protected Areas.

There has been a recent shift in global perception of plastics in the environment, resulting in a call for greater action. Science and the popular media have highlighted plastic as an increasing stressor [1,2]. Efforts have been made to confer protected status to some remote locations, forming some of the world's largest Marine Protected Areas, including several UK overseas territories. We assessed plastic at these remote Atlantic Marine Protected Areas, surveying the shore, sea surface, water column and seabed, and found drastic changes from 2013-2018. Working from the RRS James Clark Ross at Ascension, St. Helena, Tristan da Cunha, Gough and the Falkland Islands (Figure 1A), we showed that marine debris on beaches has increased more than 10 fold in the past decade. Sea surface plastics have also increased, with in-water plastics occurring at densities of 0.1 items m-3; plastics on seabeds were observed at ≤ 0.01 items m-2. For the first time, beach densities of plastics at remote South Atlantic sites approached those at industrialised North Atlantic sites. This increase even occurs hundreds of meters down on seamounts. We also investigated plastic incidence in 2,243 animals (comprising 26 species) across remote South Atlantic oceanic food webs, ranging from plankton to seabirds. We found that plastics had been ingested by primary consumers (zooplankton) to top predators (seabirds) at high rates. These findings suggest that MPA status will not mitigate the threat of plastic proliferation to this rich, unique and threatened biodiversity.

Use of the argon laser in the treatment of malleus fixation.

This case demonstrates the use of the argon laser for ossicular mobilization. A preoperative audiologic evaluation revealed a severe conductive hearing loss, with a maximum air-bone gap. Since normal drilling procedures would result in a sensorineural hearing loss, the argon laser was chosen to remove a bony spur connecting the malleus to the posterior canal wall. When using the argon laser, no disarticulation of the incus and stapes is required. Postoperative audiologic evaluation revealed normal hearing sensitivity bilaterally.

Catchments catch all: long-term population history of a giant springtail from the southeast Australian highlands--a multigene approach.

Phylogeography can reveal evolutionary processes driving natural genetic-geographical patterns in biota, providing an empirical framework for optimizing conservation strategies. The long-term population history of a rotting-log-adapted giant springtail (Collembola) from montane southeast Australia was inferred via joint analysis of mitochondrial and multiple nuclear gene genealogies. Contemporary populations were identified using multilocus nuclear genotype clustering. Very fine-scale sampling combined with nested clade and coalescent-based analyses of sequences from mitochondrial cytochrome oxidase I and three unlinked nuclear loci uncovered marked population structure, deep molecular divergences, and abrupt phylogeographical breaks over distances on the order of tens of kilometres or less. Despite adaptations that confer low mobility, rare long-distance gene flow was implicated: novel computer simulations that jointly modelled stochasticity inherent in coalescent processes and that of DNA sequence evolution showed that incomplete lineage sorting alone was unable to explain the observed spatial-genetic patterns. Impacts of Pleistocene or earlier climatic cycles were detected on multiple timescales, and at least three putative moist forest refuges were identified. Water catchment divisions predict phylogeographical patterning and present-day population structure with high precision, and may serve as an excellent surrogate for biodiversity indication in sedentary arthropods from topographically heterogeneous montane temperate forests.

Phylogeography recapitulates topography: very fine-scale local endemism of a saproxylic 'giant' springtail at Tallaganda in the Great Dividing Range of south-east Australia.

Comparative phylogeography can reveal processes and historical events that shape the biodiversity of species and communities. As part of a comparative research program, the phylogeography of a new, endemic Australian genus and species of log-dependent (saproxylic) collembola was investigated using mitochondrial sequences, allozymes and anonymous single-copy nuclear markers. We found the genetic structure of the species corresponds with five a priori microbiogeographical regions, with population subdivision at various depths owing to palaeoclimatic influences. Closely related mtDNA haplotypes are codistributed within a single region or occur in adjacent regions, nuclear allele frequencies are more similar among more proximate populations, and interpopulation migration is rare. Based on mtDNA divergence, a late Miocene-late Pliocene coalescence is likely. The present-day distribution of genetic diversity seems to have been impacted by three major climatic events: Pliocene cooling and drying (2.5-7 million years before present, Mybp), early Pleistocene wet-dry oscillations (c. 1.2 Mybp) and the more recent glacial-interglacial cycles that have characterized the latter part of the Quaternary (<0.4 Mybp).

Toxic shock syndrome related to nasal packing.

While toxic shock syndrome (TSS) is generally considered to be a tampon-related illness, an increasing number of reported cases have been related to surgical wounds. At least one case has been reported following nasal surgery with nasal packing. We report two additional cases of TSS associated with nasal packing. Because nasal packing is in some ways analogous to the use of tampons for menstrual hygiene, and nasal carriage of Staphylococcus aureus is frequent, the scarcity of TSS cases reported to occur following nasal packing is surprising. Otorhinolaryngologists are urged to report TSS cases associated with nasal packing to their state and local health departments or the Centers for Disease Control to aid in the understanding of the pathogenesis of this disease.