Identifying potentially invasive non-native marine and brackish water species for the Arabian Gulf and Sea of Oman

Invasive non‐native species (NNS) are internationally recognized as posing a serious threat to global biodiversity, economies and human health. The identification of invasive NNS is already established, those that may arrive in the future, their vectors and pathways of introduction and spread, and hotspots of invasion are important for a targeted approach to managing introductions and impacts at local, regional and global scales. The aim of this study was to identify which marine and brackish NNS are already present in marine systems of the northeastern Arabia area (Arabian Gulf and Sea of Oman) and of these which ones are potentially invasive, and which species have a high likelihood of being introduced in the future and negatively affect biodiversity. Overall, 136 NNS were identified, of which 56 are already present in the region and a further 80 were identified as likely to arrive in the future, including fish, tunicates, invertebrates, plants and protists. The Aquatic Species Invasiveness Screening Kit (AS‐ISK) was used to identify the risk of NNS being (or becoming) invasive within the region. Based on the AS‐ISK basic risk assessment (BRA) thresholds, 36 extant and 37 horizon species (53.7% of all species) were identified as high risk. When the impact of climate change on the overall assessment was considered, the combined risk score (BRA+CCA) increased for 38.2% of all species, suggesting higher risk under warmer conditions, including the highest‐risk horizon NNS the green crab Carcinus maenas, and the extant macro‐alga Hypnea musciformis. This is the first horizon‐scanning exercise for NNS in the region, thus providing a vital baseline for future management. The outcome of this study is the prioritization of NNS to inform decision‐making for the targeted monitoring and management in the region to prevent new bio‐invasions and to control existing species, including their potential for spread

Antarctic Bacteria as Astrobiological Models

Antarctica contains many different types of habitat that would traditionally be considered harsh from a human perspective; it can be extremely cold, have low levels of liquid water, low humidity, low nutrient availability, high levels of salinity and high levels of non-ionizing radiation. Yet a wide variety of bacteria have been found living there, despite these harsh conditions; some of them are believed to be unique to the continent, others more cosmopolitan in distribution. When we compare aspects of these Antarctic habitats to conditions known to occur on Mars, or to what is known of the icy moons of Jupiter and Saturn, we find notable similarities even though, clearly, significant differences remain. It is therefore unsurprising that scientists have used bacteria isolated from the Antarctic as astrobiological models. The extent to which this has been done to date, however, is perhaps surprisingly limited despite the enormous potential in this approach. In this chapter, we examine the differences and similarities between specific habitats in Antarctica and those which they might mimic on Mars, Europa and Enceladus. It considers the nature of the microbiological adaptions found in these Antarctic habitats and the experiments carried out to date on bacteria isolated from them. The chapter concludes by discussing the future potential of Antarctic bacterial species as well as the lessons learnt in understanding the limits of life here on Earth and the possibility of finding evidence of microbial life elsewhere in the solar system