A glimpse into the biogeography, seasonality, and ecological functions of arctic marine Oomycota

Source at https://doi.org/10.1186/s43008-019-0006-6. © The Author(s). 2019High-latitude environments are warming, leading to changes in biological diversity patterns of taxa. Oomycota are a group of fungal-like organisms that comprise a major clade of eukaryotic life and are parasites of fish, agricultural crops, and algae. The diversity, functionality, and distribution of these organisms are essentially unknown in the Arctic marine environment. Thus, it was our aim to conduct a first screening, using a functional gene assay and high-throughput sequencing of two gene regions within the 18S rRNA locus to examine the diversity, richness, and phylogeny of marine Oomycota within Arctic sediment, seawater, and sea ice. We detected Oomycota at every site sampled and identified regionally localized taxa, as well as taxa that existed in both Alaska and Svalbard. While the recently described diatom parasite Miracula helgolandica made up about 50% of the oomycete reads found, many lineages were observed that could not be assigned to known species, including several that clustered with another recently described diatom parasite, Olpidiopsis drebesii. Across the Arctic, Oomycota comprised a maximum of 6% of the entire eukaryotic microbial community in Barrow, Alaska May sediment and 10% in sea ice near the Svalbard archipelago. We found Arctic marine Oomycota encode numerous genes involved in parasitism and carbon cycling processes. Ultimately, these data suggest that Arctic marine Oomycota are a reservoir of uncharacterized biodiversity, the majority of which are probably parasites of diatoms, while others might cryptically cycle carbon or interface other unknown ecological processes. As the Arctic continues to warm, lower-latitude Oomycota might migrate into the Arctic Ocean and parasitize non-coevolved hosts, leading to incalculable shifts in the primary producer community

Integrating the voluntary sector in personalised care: mixed methods study of the outcomes from wellbeing co-ordination for adults with complex needs

PurposeThis integrated care study seeks to highlight how voluntary sector “wellbeing co-ordinators” co-located in a horizontally and vertically integrated, multidisciplinary community hub within one locality of an Integrated Care Organisation contribute to complex, person-centred, co-ordinated care.Design/methodology/approachThis is a naturalistic, mixed method and mixed data study. It is complementing a before-and-after study with a sub-group analysis of people receiving input from the wider hub (including Wellbeing Co-ordination and Enhanced Intermediate Care), qualitative case studies, interviews, and observations co-produced with embedded researchers-in-residence.FindingsThe cross-case analysis uses trajectories and outcome patterns across six client groups to illustrate the bio-psycho-social complexity of each group across the life course, corresponding with the range of inputs offered by the hub.Research limitations/implicationsTo consider the effectiveness and mechanisms of complex system-wide interventions operating at horizontal and vertical interfaces and researching this applying co-produced, embedded, naturalistic and mixed methods approaches.Practical implicationsHow a bio-psycho-social approach by a wellbeing co-ordinator can contribute to improved person reported outcomes from a range of preventive, rehabilitation, palliative care and bereavement services in the community.Social implicationsTo combine knowledge about individuals held in the community to align the respective inputs, and expectations about outcomes while considering networked pathways based on functional status, above diagnostic pathways, and along a life-continuum.Originality/valueThe hub as a whole seems to (1) Enhance engagement through relationship, trust and activation, (2) Exchanging knowledge to co-create a shared bio-psycho-social understanding of each individual’s situation and goals, (3) Personalising care planning by utilising the range of available resources to ensure needs are met, and (4) Enhancing co-ordination and ongoing care through multi-disciplinary working between practitioners, across teams and sectors.</jats:sec

Accessibility and implementation in the UK NHS services of an effective depression relapse prevention programme: learning from mindfulness-based cognitive therapy through a mixed-methods study

ArticleThis is the author accepted manuscript. The final version is available from NIHR Health Technology Assessment Programme via the link in this record.Access to mindfulness-based cognitive therapy for preventing depression relapse remains variable across the UK, but can be improved by individuals who champion implementation locally, often over many years, and in challenging contexts

Seasonality in land–ocean connectivity and local processes control sediment bacterial community structure and function in a High Arctic tidal flat

Climate change is altering patterns of precipitation, cryosphere thaw, and land–ocean influxes, affecting understudied Arctic estuarine tidal flats. These transitional zones between terrestrial and marine systems are hotspots for biogeochemical cycling, often driven by microbial processes. We investigated surface sediment bacterial community composition and function from May to September along a river–intertidal–subtidal–fjord gradient. We paired metabarcoding of in situ communities with in vitro carbon-source utilization assays. Bacterial communities differed in space and time, alongside varying environmental conditions driven by local seasonal processes and riverine inputs, with salinity emerging as the dominant structuring factor. Terrestrial and riverine taxa were found throughout the system, likely transported with runoff. In vitro assays revealed sediment bacteria utilized a broader range of organic matter substrates when incubated in fresh and brackish water compared to marine water. These results highlight the importance of salinity for ecosystem processes in these dynamic tidal flats, with the highest potential for utilization of terrestrially derived organic matter likely limited to tidal flat areas (and times) where sediments are permeated by freshwater. Our results demonstrate that intertidal flats must be included in future studies on impacts of increased riverine discharge and transport of terrestrial organic matter on coastal carbon cycling in a warming Arctic.publishedVersio

Light and freshwater discharge drive the biogeochemistry and microbial ecology in a sub-Arctic fjord over the Polar night

The polar night has recently received increased attention as a surprisingly active biological season. Yet, polar night microbial ecology is a vastly understudied field. To identify the physical and biogeochemical parameters driving microbial activity over the dark season, we studied a sub-Arctic fjord system in northern Norway from autumn to early spring with detailed monthly sampling. We focused on the impact of mixing, terrestrial organic matter input and light on microbial ecosystem dynamics. Our study highlights strong differences in the key drivers between spring, autumn, and winter. The spring bloom started in March in a fully mixed water column, opposing the traditional critical depth hypothesis. Incident solar radiation was the key driver maximum Chlorophyll was reached in April. The onset of the autumn phytoplankton bloom was controlled by vertical mixing, causing nutrient upwelling and dilution of zooplankton grazers, which had their highest biomass during this time. According to the dilution-recoupling hypothesis grazer dilution reduced grazing stress and allowed the fall bloom formation. Mixing at that time was initiated by strong winds and reduced stratification as a consequence of freezing temperatures and lower freshwater runoff. During the light-limited polar night, the primary production was extremely low but bacteria continued growing on decaying algae, their exudates and also allochthonous organic matter. A melting event in January could have increased input of organic matter from land, supporting a mid-winter bacterial bloom. In conclusion, polar night biogeochemistry and microbial ecology was not only driven by light availability, but strongly affected by variability in reshwater discharge and allochthonous carbon input. With climate change freshwater discharge will increase in the Arctic, which will likely increase importance of the dynamics described in this study

Recovery from recurrent depression with mindfulness-based cognitive therapy and antidepressants: a qualitative study with illustrative case studies

Objectives: This study aimed to describe the recovery journeys of people with a history of recurrent depression who took part in a psychosocial programme designed to teach skills to prevent depressive relapse (mindfulness-based cognitive therapy (MBCT)), alongside maintenance antidepressant medication (ADM). Design: A qualitative study embedded within a multicentre, single blind, randomised controlled trial (the PREVENT trial). Setting: Primary care urban and rural settings in the UK. Participants 42 people who participated in the MBCT arm of the parent trial were purposively sampled to represent a range of recovery journeys. Interventions: MBCT involves eight weekly group sessions, with four refresher sessions offered in the year following the end of the programme. It was adapted to offer bespoke support around ADM tapering and discontinuation. Methods: Written feedback and structured in-depth interviews were collected in the 2 years after participants undertook MBCT. Data were analysed using thematic analysis and case studies constructed to illustrate the findings. Results: People with recurrent depression have unique recovery journeys that shape and are shaped by their pharmacological and psychological treatment choices. Their journeys typically include several over-arching themes: (1) beliefs about the causes of depression, both biological and psychosocial; (2) personal agency, including expectations about their role in recovery and treatment; (3) acceptance, both of depression itself and the recovery journey; (4) quality of life; (5) experiences and perspectives on ADM and ADM tapering-discontinuation; and (6) the role of general practitioners, both positive and negative. Conclusions: People with recurrent depression describe unique, complex recovery journeys shaped by their experiences of depression, treatment and interactions with health professionals. Understanding how several themes coalesce for each individual can both support their recovery and treatment choices as well as health professionals in providing more accessible, collaborative, individualised and empowering care. :Trial registration number: Clinical trial number ISRCTN26666654; post results.</p

Seasonal Variability in the Zooplankton Community Structure in a Sub-Arctic Fjord as Revealed by Morphological and Molecular Approaches

Phyto- and zooplankton in Arctic and sub-Arctic seas show very strong seasonal changes in diversity and biomass. Here we document the seasonal variability in the mesozooplankton community structure in a sub-Arctic fjord in Northern Norway based on monthly sampling between November 2018 and February 2020. We combined traditional morphological zooplankton identification with DNA metabarcoding of a 313 base pair fragment of the COI gene. This approach allowed us to provide the most detailed mesozooplankton species list known for this region across an entire year, including both holo- and meroplankton. The zooplankton community was dominated by small copepods throughout the sampling period both in terms of abundance and relative sequence counts. However, meroplankton was the most diverse group, especially within the phylum polychaeta. We identified four distinct periods based on the seasonal analysis of the zooplankton community composition. The pre-spring bloom period (February–March) was characterized by low abundance and biomass of zooplankton. The spring bloom (April) was characterized by the presence of Calanus young stages, cirripedia and krill eggs. The spring-summer period (May–August) was characterized by a succession of meroplankton and a relatively high abundance of copepods of the genus Calanus spp. Finally, the autumn-winter period (September–December) was characterized by a high copepod diversity and a peak in abundance of small copepods (e.g., Oithona similis, Acartia longiremis, Pseudocalanus acuspes, Pseudocalanus elongatus, Pseudocalanus moultoni, Pseudocalanus minutus). During this period, we also observed an influx of boreal warm-water species which were notably absent during the rest of the year. Both the traditional community analysis and metabarcoding were highly complementary and with a few exceptions showed similar trends in the seasonal changes of the zooplankton community structure

Modelling Silicate - Nitrate - Ammonium Co-Limitation of Algal Growth and the Importance of Bacterial Remineralisation Based on an Experimental Arctic Coastal Spring Bloom Culture Study

Arctic coastal ecosystems are rapidly changing due to climate warming, which makes modelling their productivity crucially important to better understand future changes. System primary production in these systems is highest during the pronounced spring bloom, typically dominated by diatoms. Eventually the spring blooms terminate due to silicon or nitrogen limitation. Bacteria can play an important role for extending bloom duration and total CO2 fixation through ammonium regeneration. Current ecosystem models often simplify the effects of nutrient co-limitations on algal physiology and cellular ratios and neglect bacterial driven regeneration, leading to an underestimation of primary production. Detailed biochemistry- and cell-based models can represent these dynamics but are difficult to tune in the environment. We performed a cultivation experiment that showed typical spring bloom dynamics, such as extended algal growth via bacteria ammonium remineralisation, and reduced algal growth and inhibited chlorophyll synthesis under silicate limitation, and gradually reduced nitrogen assimilation and chlorophyll synthesis under nitrogen limitation. We developed a simplified dynamic model to represent these processes. The model also highlights the importance of organic matter excretion, and post bloom ammonium accumulation. Overall, model complexity is comparable to other ecosystem models used in the Arctic while improving the representation of nutrient co-limitation related processes. Such model enhancements that now incorporate increased nutrient inputs and higher mineralization rates in a warmer climate will improve future predictions in this vulnerable system

Seasonality in phytoplankton communities and production in three Arctic fjords across a climate gradient

Phytoplankton communities and production in Arctic fjords undergo strong seasonal variations. Phytoplankton blooms are periods with high primary production, leading to elevated algal biomass fueling higher trophic levels. Blooms are typically driven bottom-up by light and nutrient availability but may also be top-down controlled by grazing. While phytoplankton spring blooms are common across all Arctic systems, summer and autumn blooms and their drivers are less predictable. Here we compare the long-term (≥4 years) bloom phenology and protist community composition in three Arctic fjords: Nuup Kangerlua in western Greenland, Ramfjorden in northern Norway, and Adventfjorden in western Svalbard. While Nuup Kangerlua is impacted by tidewater glaciers, Ramfjorden and Adventfjorden are impacted by river-runoff. We discuss and contrast the presence and predictability of spring, summer, and autumn blooms in these fjords and the main physical, chemical, and biological drivers. Spring blooms occurred in all three fjords in April/May as soon as sufficient sunlight was available and typically terminated when nutrients were depleted. Chain-forming diatoms together with the haptophyte Phaeocystis pouchetii were key spring bloom taxa in all three fjords. Summer blooms were found in Nuup Kangerlua and Ramfjorden but were not common in Adventfjorden. In Nuup Kangerlua nutrient supply via subglacial upwelling was the key driver of a diatom-dominated summer bloom. This summer bloom extended far into autumn with strong winds resupplying nutrients to the surface later in the season. In Ramfjorden runoff from a vegetated catchment provided organic nutrients for a flagellate-dominated summer bloom in 2019. A late autumn bloom dominated by Skeletonema spp. and other chain-forming diatoms was present after nutrients were resupplied by wind mixing. In Adventfjorden, we observed only minor summer blooms in 2 of the 8 years, while autumn blooms were never observed. With global warming, we suggest that summer blooms will be negatively impacted in fjords where tidewater glaciers retreat and become land terminating. In fjords with rich vegetated catchments, harmful algal blooms may occur more frequently as summers and autumns become warmer and wetter. However, for fjords in high-Arctic latitudes (>78 N), the day length will continue to restrict the potential for autumn blooms.publishedVersio