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Linking vertical movements of large pelagic predators with distribution patterns of biomass in the open ocean
No full textMany predator species make regular excursions from near-surface waters to the twilight (200 to 1,000 m) and midnight (1,000 to 3,000 m) zones of the deep pelagic ocean. While the occurrence of significant vertical movements into the deep ocean has evolved independently across taxonomic groups, the functional role(s) and ecological significance of these movements remain poorly understood. Here, we integrate results from satellite tagging efforts with model predictions of deep prey layers in the North Atlantic Ocean to determine whether prey distributions are correlated with vertical habitat use across 12 species of predators. Using 3D movement data for 344 individuals who traversed nearly 1.5 million km of pelagic ocean in
42,000 d, we found that nearly every tagged predator frequented the twilight zone and many made regular trips to the midnight zone. Using a predictive model, we found clear alignment of predator depth use with the expected location of deep pelagic prey for at least half of the predator species. We compared high-resolution predator data with shipboard acoustics and selected representative matches that highlight the opportunities and challenges in the analysis and synthesis of these data. While not all observed behavior was consistent with estimated prey availability at depth, our results suggest that deep pelagic biomass likely has high ecological value for a suite of commercially important predators in the open ocean. Careful consideration of the disruption to ecosystem services provided by pelagic food webs is needed before the potential costs and benefits of proceeding with extractive activities in the deep ocean can be evaluated
An assessment of the ecosystem services of marine zooplankton and the key threats to their provision
Get PDFZooplankton are a key group of organisms at the base of the marine food web and are fundamental to providing a
broad range of societal and economic benefits which have previously remained poorly defined. This research
addresses this knowledge gap through the provision of a first full assessment of zooplankton ecosystem services
and disservices. Anthropogenic stressors such as microplastic pollution, climate change, and fisheries, could
negatively affect the marine ecosystem services provided to humans and therefore have a negative impact on
human well-being through reduction in food security, livelihoods, income, and good health. Deploying a mixed
methodology approach including a semi-systematic literature review and ecological impact assessment, we
provide novel evidence of the effects of microplastic pollution (high and low concentrations), fisheries, and
climate change on the ecosystem services of three important zooplankton groups (copepods, jellyfish, and krill).
We show that the majority of impacts on ecosystem services are negative, with the exception of climate change
on jellyfish ecosystem services. Climate change and high microplastic concentration are evidenced to have the
most substantial negative impacts on copepods and krill, with accompanying implications for the ecosystem
services of climate regulation, water conditions, other materials, science, and entertainment. High microplastic
concentration also depressed ecosystem service provision for jellyfish, impacting the services of genetic mate�rials, climate regulation, water conditions, education, and entertainment. Fisheries are also evidenced to have
negative impacts on all three zooplankton groups. In the case of jellyfish, climate change is evidenced to have a
positive impact on the group’s ecosystem service provision in every category except experiential experiences,
which is inversely related to increasing population, owing to their negative perception due to sting injuries. The
evidence presented in this study shows that by maintaining sustainable fisheries, reducing plastic pollution, and
minimising climate change, we will be actively investing in the current and future provision of marine ecosystem
services and the human well-being benefits that they provide
The link between surface and sub-surface chlorophyll-a in the centre of the Atlantic subtropical gyres: a comparison of observations and models
Get PDFSatellite observations have given us a clear idea of the changes in chlorophyll in the surface ocean on both a seasonal and interannual basis, but repeated observations at
depth are much rarer. The permanently-stratified subtropical gyres in the Atlantic are highly oligotrophic, with most production centred on a deep chlorophyll maximum (DCM) just above the nitracline. This study explores the variations in this feature in the core of both gyres, considering both seasonal and interannual variations, and the linkages between changes at the surface and sub-surface. The in situ observations come from the Atlantic Meridional Transect (AMT), a long-running UK monitoring programme, and also from biogeochemical Argo floats. AMT provides measurements spanning more than 25 years directed through the centres of these gyres, but samples only 2 to 4 months per year and thus cannot resolve the seasonal variations, whereas the profiling floats give coverage throughout the year, but without the rigid spatial repeatability. These observational records are contrasted
with representation of the centres of the gyres in two different biogeochemical models: MEDUSA and ERSEM, thus fulfilling one of AMT’s stated aims: the assessment of biogeochemical models. Whilst the four datasets show broadly the same seasonal patterns and that the DCM shallows when surface chlorophyll increases, the depth and peak concentration of the DCM differ among datasets. For most of the datasets the column-integrated chlorophyll for both gyres is around
19 mg m-2 (with the AMT fluorescence-derived values being much lower); however the MEDUSA model has a disparity between the northern and southern gyres that is not understood. Although the seasonal increase in surface chlorophyll is tied to a
commensurate decrease in concentration at depth, on an interannual basis years with enhanced surface levels of chlorophyll correspond to increases at depth. Satellite-derived observations of surface chlorophyll concentration act as a good
predictor of interannual changes in DCM depth for both gyres during their autumn season, but provide less skill in spring
Spatiotemporal cytosolic Ca2+ signals in plants and algae: divergent means to an end
No full textThe ability to generate distinct spatiotemporal patterns of cytosolic calcium concentration (Ca2+cyt) is a fundamental property of eukaryotic cells and underlies responses to external stimuli as well as directing downstream processes involved in morphogenesis, growth, and even developmental fate. In this review, we consider a number of well-studied and less well-studied photosynthetic plant and algal systems from the point of view of the different Ca2+ channel types that underlie spatiotemporal Ca2+cyt patterns. These include pollen tubes, root hairs, moss protonema, algal rhizoids, and single-celled algae. We show that similar spatial and temporal Ca2+cyt patterns can be brought about by the coordinated activities of a range of Ca2+ channel types. Most significantly, these channel types vary widely between different photosynthetic groups, indicating that the conserved necessity to generate spatiotemporal Ca2+ signals is satisfied by divergent underlying mechanisms, likely reflecting the different evolutionary pressures on ion transport mechanisms across the photosynthetic eukaryote clades
Spatial variability in the structure of fish assemblages associated with Laminaria hyperborea forests in the NE Atlantic
Get PDFUnderstanding fish-habitat associations is critical for ecosystem-based approaches to management and conservation. Kelp species, which are estimated to inhabit around 25% of the world's coastline and underpin highly productive and biodiverse ecosystems, are widely recognised as important nursery and foraging habitats for coastal fish species. However, quantitative assessments of fish assemblages within kelp forests are lacking for many regions. Here, we used Baited Remote Underwater Video (BRUV) and Underwater Visual Census (UVC) to quantify fish assemblages in Laminaria hyperborea forests at eight shallow subtidal rocky reefs that spanned 9° of latitude in the United Kingdom (UK). Fish assemblages were a ubiquitous and conspicuous component of kelp forest communities at all sites. BRUV surveys recorded marked regional-scale variability, with latitudinal shifts in assemblage structure and particularly distinct assemblages recorded in southwest England. These patterns were largely due to greater abundances of Pollachius spp. (i.e. saithe and pollock) in northern regions and higher numbers of Gobiusculus flavescens (two-spotted goby) and labrid species (i.e. rock cook, goldsinny and ballan wrasses) in southern regions. Unlike BRUVs, UVC surveys did not detect significant regional-scale variation in assemblage structure but did detect significant site-level differences, highlighting differences between the two techniques. BRUV surveys also recorded clear latitudinal trends in richness, with more taxa recorded at lower latitudes. Fish assemblages in the NE Atlantic have been, and will continue to be, impacted by ocean warming and fishing activities. Greater spatiotemporal coverage of kelp forest surveys and ongoing robust monitoring is needed to better understand and manage future ecological changes
GLORIA - A globally representative hyperspectral in situ dataset for optical sensing of water quality
Get PDFThe development of algorithms for remote sensing of water quality (RSWQ) requires a large amount of in situ data to account for the bio-geo-optical diversity of inland and coastal waters. The GLObal Reflectance community dataset for Imaging and optical sensing of Aquatic environments (GLORIA) includes 7,572 curated hyperspectral remote sensing reflectance measurements at 1 nm intervals within the 350 to 900 nm wavelength range. In addition, at least one co-located water quality measurement of chlorophyll a, total suspended solids, absorption by dissolved substances, and Secchi depth, is provided. The data were contributed by researchers affiliated with 59 institutions worldwide and come from 450 different water bodies, making GLORIA the de-facto state of knowledge of in situ coastal and inland aquatic optical diversity. Each measurement is documented with comprehensive methodological details, allowing users to evaluate fitness-for-purpose, and providing a reference for practitioners planning similar measurements. We provide open and free access to this dataset with the goal of enabling scientific and technological advancement towards operational regional and global RSWQ monitoring
Rapid seaward expansion of seaport footprints worldwide
Get PDFAs global maritime traffic increases, seaports grow to accommodate and compete for higher volumes of trade throughput. However, growth trajectories of seaport footprints around the world have gone unmeasured, likely because of a lack of readily available spatio-temporal data. Here, we use geospatial analysis of global satellite imagery from 1990–2020 to show that 65 seaports among the world’s top 100 container ports, as ranked by reported throughput, have been expanding rapidly seaward. Collectively, these seaports have added approximately 978 km2 in gross port area in three decades through coastal land reclamation. We also find that the relationship between footprint expansion and throughput volume is highly variable among seaports. Understanding patterns of seaport expansion in space and time informs global assessments of critical infrastructure and supply chain vulnerability to climate-driven hazard. Seaport expansion also sets up complex trade-offs in the context of environmental impacts and climate adaptation
Ocean carbon from space: Current status and priorities for the next decade
Get PDFThe ocean plays a central role in modulating the Earth’s carbon cycle. Monitoring how the ocean carbon cycle is changing is fundamental to managing climate change. Satellite remote sensing is currently our best tool for viewing the ocean surface globally and systematically, at high spatial and temporal resolutions, and the past few decades have seen an exponential growth in studies utilising satellite data for ocean carbon research. Satellite- based observations must be combined with in-situ observations and models, to obtain a comprehensive view of ocean carbon pools and fluxes. To help prioritise future research in this area, a workshop was organised that assembled leading experts working on the topic, from around the world, including remote-sensing scientists, field scientists and modellers, with the goal to articulate a collective view of the current status of ocean carbon
research, identify gaps in knowledge, and formulate a scientific roadmap for the next decade, with an emphasis
on evaluating where satellite remote sensing may contribute. A total of 449 scientists and stakeholders participated (with balanced gender representation), from North and South America, Europe, Asia, Africa, and Oceania. Sessions targeted both inorganic and organic pools of carbon in the ocean, in both dissolved and particulate form, as well as major fluxes of carbon between reservoirs (e.g., primary production) and at interfaces (e.g., air-sea and land–ocean). Extreme events, blue carbon and carbon budgeting were also key topics discussed. Emerging priorities identified include: expanding the networks and quality of in-situ observations; improved satellite retrievals; improved uncertainty quantification; improved understanding of vertical distributions; integration with
models; improved techniques to bridge spatial and temporal scales of the different data sources; and improved
fundamental understanding of the ocean carbon cycle, and of the interactions among pools of carbon and light.
We also report on priorities for the specific pools and fluxes studied, and highlight issues and concerns that arose
during discussions, such as the need to consider the environmental impact of satellites or space activities; the role satellites can play in monitoring ocean carbon dioxide removal approaches; economic valuation of the satellite
based information; to consider how satellites can contribute to monitoring cycles of other important climatically relevant compounds and elements; to promote diversity and inclusivity in ocean carbon research; to bring together communities working on different aspects of planetary carbon; maximising use of international bodies; to follow an open science approach; to explore new and innovative ways to remotely monitor ocean carbon; and to harness quantum computing. Overall, this paper provides a comprehensive scientific roadmap for the next
decade on how satellite remote sensing could help monitor the ocean carbon cycle, and its links to the other domains, such as terrestrial and atmosphere
Phytoplankton life strategies, phenological shifts and climate change in the North Atlantic Ocean from 1850 to 2100
Get PDFSignificant phenological shifts induced by climate change are projected within the phytoplankton community. However, projections from current Earth System Models (ESMs) understandably rely on simplified community responses that do not consider evolutionary strategies manifested as various phenotypes and trait groups. Here, we use a species-based modelling approach, combined with large-scale plankton observations, to investigate past, contemporary and future phenological shifts in diatoms (grouped by their morphological traits) and dinoflagellates in three key areas of the North Atlantic Ocean (North Sea, North-East Atlantic and Labrador Sea) from 1850 to 2100. Our study reveals that the three phytoplanktonic groups exhibit coherent and different shifts in phenology and abundance throughout the North Atlantic Ocean. The seasonal duration of large flattened (i.e. oblate) diatoms is predicted to shrink and their abundance to decline, whereas the phenology of slow-sinking elongated (i.e. prolate) diatoms and of dinoflagellates is expected to expand and their abundance to rise, which may alter carbon export in this important sink region. The increase in prolates and dinoflagellates, two groups currently not considered in ESMs, may alleviate the negative influence of global climate change on oblates, which are responsible of massive peaks of biomass and carbon export in spring. We suggest that including prolates and dinoflagellates in models may improve our understanding of the influence of global climate change on the biological carbon cycle in the oceans
Lichen zonation on UK rocky seashores: a trait-based approach to delineating marine and maritime lic
No full textLichenized fungi are a major component of coastal marine ecosystems. Their distributions transition through a range of distinct environmental pressures that span from daily immersion in sea water to fully terrestrial ecosystems, sometimes within the space of only a few metres (Hawksworth 2000). Natural environmental gradients such as these are important for investigating ecological and evolutionary mechanisms due to their ability to drive shifts in species assemblage, niche differentiation, and local adaptation (Prieto et al. 2017)