Impact of ocean acidification on the intestinal microbiota of the marine sea bream (Sparus aurata L.)

Within a scenario of increasing atmospheric CO2 and ocean acidification (OA), it is highly relevant to investigate its impacts not only on fish performance but also on fish intestinal microbiome and how that reflects on host performance and health. The main objective of this study was to establish if the intestinal microbiota of the sea bream (Sparus aurata) was affected by high level of CO2 in line with the predictions for this century. The bacterial communities of the intestinal fluid were characterized in animals kept at the present-day level of CO2 (400 μatm) and in animals switched to high CO2 (1200 μatm) for 1 month. Bacterial taxa identification was based on molecular methods, using the DNA coding for the 16S ribosomal RNA and primers targeting the regions V1-V3. Amplicons obtained from DNA samples of animals in the same tank were combined, cloned to obtain a bacterial DNA library, and the clones were sequenced. No significant differences were found between the two treatments for alpha diversity. However, beta diversity analysis revealed distinct dysbiosis in response to hypercapnia, with phylum Firmicutes absent from the bacterial communities of fish exposed to 1200 μatm CO2, whereas Proteobacteria relative abundance was increased at elevated CO2, due to the presence of Gammaproteobacteria (Vibrionaceae and Alteromonadaceae), a class not present in the control samples. This study provides a first glimpse at the impact of OA in fish intestinal microbiota and highlights potential downstream effects to the general condition of fishes under hypercapnia.Funding Agency Portuguese Foundation for Science and Technology PTDC/MAR-BIO/3034/2014 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 Ministry of Science and Higher Education, Polandinfo:eu-repo/semantics/publishedVersio

Lessons from two high CO2 worlds - future oceans and intensive aquaculture

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Exponentially rising CO2 (currently ~400 μatm) is driving climate change and causing acidification of both marine and freshwater environments. Physiologists have long known that CO2 directly affects acid-base and ion regulation, respiratory function and aerobic performance in aquatic animals. More recently, many studies have demonstrated that elevated CO2 projected for end of this century (e.g. 800-1000 μatm) can also impact physiology, and have substantial effects on behaviours linked to sensory stimuli (smell, hearing and vision) both having negative implications for fitness and survival. In contrast, the aquaculture industry was farming aquatic animals at CO2 levels that far exceed end-of-century climate change projections (sometimes >10 000 μatm) long before the term 'ocean acidification' was coined, with limited detrimental effects reported. It is therefore vital to understand the reasons behind this apparent discrepancy. Potential explanations include 1) the use of 'control' CO2 levels in aquaculture studies that go beyond 2100 projections in an ocean acidification context; 2) the relatively benign environment in aquaculture (abundant food, disease protection, absence of predators) compared to the wild; 3) aquaculture species having been chosen due to their natural tolerance to the intensive conditions, including CO2 levels; or 4) the breeding of species within intensive aquaculture having further selected traits that confer tolerance to elevated CO2 . We highlight this issue and outline the insights that climate change and aquaculture science can offer for both marine and freshwater settings. Integrating these two fields will stimulate discussion on the direction of future cross-disciplinary research. In doing so, this article aimed to optimize future research efforts and elucidate effective mitigation strategies for managing the negative impacts of elevated CO2 on future aquatic ecosystems and the sustainability of fish and shellfish aquaculture.The authors wish to acknowledge the funding that has contributed to ideas within this manuscript. This includes a United Kingdom Ocean Acidification Research Program (UKOARP) Project (NE/H01750X/1 to R.W.W.) cofunded by the Natural Environment Research Council (NERC), the Department for Environment, Food and Rural Affairs (Defra) and the Department of Energy and Climate Change (DECC), together with various BBSRC-funded projects (BB/J00913X/1, BB/N013344/1 and BB/M017583/1 to R.W.W.)

Economic Thought of Vincent de Gournay (4)

Ongoing climate change is predicted to affect the distribution and abundance of aquatic ectotherms owing to increasing constraints on organismal physiology, in particular involving the metabolic scope (MS) available for performance and fitness. The oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis prescribes MS as an overarching benchmark for fitness-related performance and assumes that any anaerobic contribution within the MS is insignificant. The MS is typically derived from respirometry by subtracting standard metabolic rate from the maximal metabolic rate; however, the methodology rarely accounts for anaerobic metabolism within the MS. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), this study tested for trade-offs (i) between aerobic and anaerobic components of locomotor performance; and (ii) between the corresponding components of the MS. Data collection involved measuring oxygen consumption rate at increasing swimming speeds, using the gait transition from steady to unsteady (burst-assisted) swimming to detect the onset of anaerobic metabolism. Results provided evidence of the locomotor performance trade-off, but only in S. aurata. In contrast, both species revealed significant negative correlations between aerobic and anaerobic components of the MS, indicating a trade-off where both components of the MS cannot be optimized simultaneously. Importantly, the fraction of the MS influenced by anaerobic metabolism was on average 24.3 and 26.1% in S. aurata and P. reticulata, respectively. These data highlight the importance of taking anaerobic metabolism into account when assessing effects of environmental variation on the MS, because the fraction where anaerobic metabolism occurs is a poor indicator of sustainable aerobic performance. Our results suggest that without accounting for anaerobic metabolism within the MS, studies involving the OCLTT hypothesis could overestimate the metabolic scope available for sustainable activities and the ability of individuals and species to cope with climate change

Retrieval of Ice Samples Using the Ice Drone

The ecological impacts of meltwater produced by icebergs and sea ice in the waters around Greenland are poorly understood, due in part to limited observations. Current field sampling methods are resource and labor-intensive, and not without significant risk. We developed a small, unoccupied, and robotic platform to retrieve ice samples, while simultaneously eliminating safety risks to scientists and their support infrastructure. The IceDrone consists of a modified commercial hexcopter that retrieves ice samples. We describe the design requirements, construction, and testing of the IceDrone. IceDrone's capabilities were validated in the laboratory and during a field test in January 2019 near Nuuk (southwest Greenland). IceDrone retrieved samples in hard and dry glacial ice in harsh winter conditions. The field test led to modifications in the drilling head design and drilling process that enable it to retrieve samples in thin sea ice. All design files and software are provided in an attempt to rapidly enhance our collective understanding of ice-ocean interactions while improving the safety and productivity of field sampling campaigns

Lithostratigraphy, sedimentary evolution and sequence stratigraphy of the Upper Proterozoic Lyell Land Group (Eleonore Bay Supergroup) of East and North-East Greenland

The Late Proterozoic Lyell Land Group is an approximately 3 km thick succession of siliciclastic shelf deposits, within the upper part of the Eleonore Bay Supergroup. It is widely exposed in the region between Ardencaple Fjord in the north and Canning Land in the south. In this paper the seven formations named by Sønderholm &amp; Tirsgaard (1993) are formally described. These are from base to top: the Kempe Fjord Formation (400-600 m thick), the Sandertop Formation (200-405 m thick), the Berzelius Bjerg Formation (250-450 m thick), the Kap Alfred Formation (500-640 m thick), the Vibeke Sø Formation (290-325 m thick), the Skjoldungebrae Formation (205-240 m thick) and the Teufelsschloss Formation (35-110 m thick).&#x0D; Five facies associations have been recognised. Outer shelf deposits dominated by dark green, brown to dark red mudstones with thin sandstone lenses are mainly found in the Sandertop, Kap Alfred and Skjoldungebræ Formations. Storm- and wave-dominated inner shelf deposits comprising fine-grained sandstones and dark heterolithic mudstones are common in the Sandertop, Kap Alfred, Vibeke Sø and Skjoldungebrae Formations and are also found in southern outcrops of the Teufelsschloss Formation. Tidally influenced shoreface deposits form stacks of laterally extensive sandstone bodies separated by heterolithic mudstones and are only found in the middle part of the Kap Alfred Formation. Storm- and wave-dominated shoreface deposits comprise highly mature, thick and laterally very extensive sandstone bodies of which a few may be traced for distances exceeding 150 km. This association is present in several intervals within all formations of the Lyell Land Group. Tidally dominated coastal plain deposits consist of stacked sandstone sheets forming laterally extensive, multistorey units separated by heterolithic mudstones and sandstones. These sediments form part of the Kempe Fjord and Berzelius Bjerg Formations and are also found in northern outcrops of the Teufelsschloss Formation. Evidence from palaeocurrent data combined with regional lithological variations suggest a consistent general N-S coastline with the basin deepening in an eastward direction. Deflection of geostrophic currents suggest a palaeolatitude on the southern hemisphere.&#x0D; The deposits of the Lyell Land Group are subdivided into four, large-scale sequences which overall show the same general sedimentary evolution through time reflecting large-scale, cyclic changes in relative sea-level. The sequences vary in thickness from 400-1000 m and are all readily traceable 300 km parallel and 100 km perpendicular to inferred palaeocoastline. The development of all sequences indicates that major regional translation of facies are related to large-scale forced regressions. Sequence stratigraphic considerations suggest that correlation of formations of the Lyell Land Group with units of the Petermann Bjerg Group some 75 km to the west may be very difficult to carry out.&#x0D; Citation: Tirsgaard, H. &amp; Sønderholm, M. 1997: Lithostratigraphy, sedimentary evolution and sequence stratigraphy of the Upper Proterozoic Lyell Land Group (Eleonore Bay Supergroup) of East and North-East Greenland. Geology of Greenland Survey Bulletin 178, 60 pp.</jats:p