Operation Crayweed: Ecological and sociocultural aspects of restoring Sydney’s underwater forests

Operation Crayweed focuses on the restoration of underwater forests that disappeared from the coastline of Sydney, Australia’s largest city, 40 years previously. We show how a combination of science, hands‐on restoration, community engagement and art has helped the project to reach its goals as well as raise awareness about the importance of underwater kelp forests that are experiencing global decline.     

Early host–microbe interaction in a peri‐implant oral mucosa‐biofilm model

The host‐microbe relationship is pivotal for oral health as well as for peri‐implant diseases. Peri‐implant mucosa and commensal biofilm play important roles in the maintenance of host‐microbe homeostasis, but little is known about how they interact. We have therefore investigated the early host‐microbe interaction between commensal multispecies biofilm (Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, Porphyromonas gingivalis) and organotypic peri‐implant mucosa using our three‐dimensional model. After 24 hr, biofilms induced weak inflammatory reaction in the peri‐implant mucosa by upregulation of five genes related to immune response and increased secretion of IL‐6 and CCL20. Biofilm volume was reduced which might be explained by secretion of β‐Defensins‐1, ‐2, and CCL20. The specific tissue reaction without intrinsic overreaction might contribute to intact mucosa. Thus, a relationship similar to homeostasis and oral health was established within the first 24 hr. In contrast, the mucosa was damaged and the bacterial distribution was altered after 48 hr. These were accompanied by an enhanced immune response with upregulation of additional inflammatory‐related genes and increased cytokine secretion. Thus, the homeostasis‐like relationship was disrupted. Such profound knowledge of the host‐microbe interaction at the peri‐implant site may provide the basis to improve strategies for prevention and therapy of peri‐implant diseases.     

Defining CO2 and O2 syndromes of marine biomes in the Anthropocene

Research efforts have intensified to foresee the prospects for marine biomes under climate change and anthropogenic drivers over varying temporal and spatial scales. Parallel with these efforts is the utilization of terminology, such as ‘ocean acidification’ (OA) and ‘ocean deoxygenation’ (OD), that can foster rapid comprehension of complex processes driving carbon dioxide (CO₂) and oxygen (O₂) concentrations in the global ocean and thus, are now widely used in discussions within and beyond academia. However, common usage of the terms ‘acidification’ and ‘deoxygenation’ alone are subjective and, without adequate contextualization, have the potential to mislead inferences over drivers that may ultimately shape the future state of marine ecosystems. Here we clarify the usage of the terms OA and OD as global, climate change‐driven processes and discuss the various attributes of elevated CO₂ and reduced O₂ syndromes common to coastal ecosystems. We support the use of the existing terms ‘coastal acidification’ and ‘coastal deoxygenation’ because they help differentiate the sometimes rapid and extreme nature of CO₂ and O₂ syndromes in coastal ecosystems from the global, climate change‐driven processes of OA and OD. Given the complexity and breadth of the processes involved in altering CO₂ and O₂ concentrations across marine ecosystems, we provide a workflow to enable contextualization and clarification of the usage of existing terms and highlight the close link between these two gases across spatial and temporal scales in the ocean. These distinctions are crucial to guide effective communication of research within the scientific community and guide policymakers responsible for intervening on the drivers to secure desirable future ocean states.     

First case of parthenogenesis in ladybirds (Coleoptera: Coccinellidae) suggests new mechanisms for the evolution of asexual reproduction

Parthenogenesis, the development of unfertilized eggs resulting in the exclusive production of female offspring, is rare in animals relative to sexual reproduction and is mainly reported in invertebrates. It has been hypothesized that polyploidy, hybridization and endosymbiont infections are its major causal events but the mechanisms triggering asexual reproduction remain unclear. Here, we study the proximate causes at the origin of parthenogenesis in the first reported case of asexuality in the Coccinellidae (Coleoptera). The asexual populations were found in the Azores and the Mascarene archipelagos, and were identified as Nephus voeltzkowi Weise, a bisexual species widespread in sub-Saharan Africa. The specimens from both populations are diploid but present different karyotypes and heterozygosities that evoke hybrid origins, commonly associated with parthenogenesis in Coleoptera. However, the close proximity of their genomes (99.8% homology for the complete mitochondrial genome and 99.9% for the complete nuclear ribosomal cluster) together with the congruence between the mtDNA tree and the nuclear tree, and the low heterozygosity levels, suggests that the two populations are not hybrid. We propose that they belong to a single chromosomally polymorphic species undergoing Robertsonian fusions. Furthermore, specimens from both populations are infected with Wolbachia (supergroup B strain), contrary to sympatric bisexual species of the same genus. Although Wolbachia has been shown to induce parthenogenesis in haplodiploid organisms, it has been recently suggested that it could also induce parthenogenesis in hosts with other sex determination systems. Whether chromosome rearrangements and/or Wolbachia infections are post-parthenogenetic events or are at the origin of parthenogenesis still needs to be determined.     

What would it take to describe the global diversity of parasites?

How many parasites are there on Earth? Here, we use helminth parasites to highlight how little is known about parasite diversity, and how insufficient our current approach will be to describe the full scope of life on Earth. Using the largest database of host–parasite associations and one of the world’s largest parasite collections, we estimate a global total of roughly 100 000–350 000 species of helminth endoparasites of vertebrates, of which 85–95% are unknown to science. The parasites of amphibians and reptiles remain the most poorly described, but the majority of undescribed species are probably parasites of birds and bony fish. Missing species are disproportionately likely to be smaller parasites of smaller hosts in undersampled countries. At current rates, it would take centuries to comprehensively sample, collect and name vertebrate helminths. While some have suggested that macroecology can work around existing data limitations, we argue that patterns described from a small, biased sample of diversity aren’t necessarily reliable, especially as host–parasite networks are increasingly altered by global change. In the spirit of moonshots like the Human Genome Project and the Global Virome Project, we consider the idea of a Global Parasite Project: a global effort to transform parasitology and inventory parasite diversity at an unprecedented pace.