The role of oxygen and other environmental variables on survivorship, abundance, and community structure of invertebrate meroplankton of Oregon nearshore coastal waters

The high productivity of Eastern Boundary Upwelling Ecosystems (EBUE), some of the most productive ecosystems in the globe, is attributed to the nutrient rich waters brought up through upwelling. Climate change scenarios for coastal upwelling systems, predict an intensification of coastal upwelling winds. Associated with intensification in upwelling are biogeochemical changes such as ocean hypoxia and ocean acidification. In recent years, the California Current System (CCS) has experienced the occurrence of nearshore hypoxia and the novel rise of anoxia. This has been attributed to changes in the intensity of upwelling wind stress. The effects of some of the more severe hypoxia and anoxia events in the CCS have been mass mortality of fish and benthic invertebrates. However, the impacts on zooplankton in this system are not known. Meroplankton, those organisms which have a planktonic stage for only part of their life cycle, are an important component of zooplankton communities. The larval stage of benthic invertebrates forms an important link between benthic adult communities and planktonic communities. Larvae serve to disperse individuals to new locations and to link populations. They are also food for fish and planktonic invertebrates. This important life stage can spend long periods in the plankton (from days to months) where environmental conditions can affect larval health, subsequent settlement and recruitment success, and juvenile health. This research assesses the role of hypoxia and larval survivorship, and the relationship between individual abundance and community structure of larvae to environmental factors in the field. In laboratory experiments (Chapter 2), a suite of 10 rocky intertidal invertebrate species from four phyla were exposed to low oxygen conditions representative of the nearshore environment of the Oregon coast. Results revealed a wide range in tolerances from species with little tolerance (e.g. the shore crab Hemigrapsus oregonensis) to species with high tolerance (e.g. the California mussel Mytilus californianus). The differential responses across larvae to chronic hypoxia and anoxia potentially could affect their recruitment success and consequently, the structure and species composition of intertidal communities. Field studies (Chapter 3 & 4) explore the relationship between environmental variables and larval abundance and community structure. Chapter 3 focuses on broad taxonomic groups, while Chapter 4 focuses on larval decapods in particular. Fine focus was devoted to decapod larvae, due to laboratory findings of heightened sensitivity to hypoxia of decapod crabs. A finding that is also supported in the literature. The goal of field studies was to identify the environmental parameters that structure meroplankton and larval decapod communities and identify which of these parameters play a significant role in influencing larval abundance. A number of environmental variables contributed to meroplankton assemblage structure and larval decapod assemblage structure. These included distance from shore, depth, date, upwelling intensity, dissolved oxygen, and cumulative wind stress. Some of these factors occurred frequently in larval abundance models. In Chapter 3, individual abundance across broad taxonomic groups was most commonly explained by upwelling intensity while in Chapter 4, individual abundance of different decapod species was explained by cumulative wind stress, which is a proxy for upwelling intensity. The prominent role of upwelling related factors in explaining individual abundance is important considering climate change projections of an increased intensification of upwelling winds in EBUE

Engaging Northern Indigenous Communities in Biophysical Research: Pitfalls and Successful Approaches

Guidelines and best practices to engage Indigenous people in Arctic regions in biophysical research have emerged since the 1990s. Despite these guidelines, mainstream scientists still struggle to create effective working relationships with Indigenous people and engage them in their research. We encountered this issue when we visited three communities on Alaska’s west coast to study impactful weather events and the formation of “slush ice berms,” which can protect towns from storm surges. As we worked to build relationships with residents of the towns, we found the existing guidelines are often helpful for telling us what to do—for example, they emphasize the importance of face-to-face communication—but researchers also need to think about how to do it (skills) and how to be (personal attributes). To demonstrate to Indigenous people that we value and respect their culture, researchers could learn to use language that is understandable and that reflects a collaborative rather than a top-down approach. We should be ready to adjust our schedules and to help the community we are visiting, rather than simply focusing on our own needs. We might look for benefits for the community and ensure residents understand and are satisfied with the research we are doing. Some of the necessary attributes we identified are curiosity, honesty, interpersonal awareness, empathy, flexibility, and openness. Although the skills and attributes presented here are useful to bridge the gap between cultures, we caution that there is no specific formula that can guarantee success.Des lignes directrices et des pratiques exemplaires visant à faire participer les peuples autochtones des régions arctiques à la recherche biophysique sont publiées depuis les années 1990. Malgré ces lignes directrices, les scientifiques généraux ont toujours de la difficulté à créer des relations de travail efficaces avec les peuples autochtones et à les faire participer à leurs recherches. Nous avons fait face à cet enjeu quand nous avons visité trois collectivités de la côte ouest de l’Alaska pour étudier les événements climatiques percutants et la formation de « bermes de bouillie de glace » susceptibles de protéger les localités des ondes de tempête. Quand nous avons essayé de nouer des liens avec les résidents des diverses localités, nous avons constaté que les lignes directrices actuelles sont souvent utiles pour nous indiquer quoi faire (par exemple, elles mettent l’accent sur l’importance des communications face à face), mais les chercheurs doivent aussi penser à comment le faire (les compétences) et à comment se présenter (attributs personnels). Pour prouver aux Autochtones qu’ils valorisent et respectent leur culture, les chercheurs pourraient apprendre à employer du vocabulaire qui est compréhensible et qui tient compte d’une démarche de collaboration au lieu d’une démarche hiérarchique du sommet à la base. Il faudrait que nous soyons prêts à adapter nos emplois du temps et à aider la collectivité que nous visitons au lieu de nous concentrer seulement sur nos propres besoins. Il faudrait aussi considérer les avantages pour la collectivité et nous assurer que les résidents comprennent la recherche que nous faisons et soient satisfaits. Parmi les attributs nécessaires pour ces travaux de recherche, notons la curiosité, l’honnêteté, la sensibilisation aux besoins d’autrui, l’empathie, la flexibilité et l’ouverture d’esprit. Même si les compétences et les attributs dont il est question ici aident à combler l’écart entre les cultures, nous tenons à souligner qu’aucune formule particulière ne garantit le succès

Slush-Ice Berm Formation on the West Coast of Alaska

Some coastal communities in western Alaska have observed the occurrence of “slush-ice berms.” These features typically form during freeze-up, when ice crystal – laden water accumulates in piles on the shore. Slush-ice berms can protect towns from storm surge, and they can limit access to the water. Local observations from the communities of Gambell, Shaktoolik, Shishmaref, and Wales were synthesized to develop a taxonomy of slush-ice berm types and a conceptual process model that describes how they form and decay. Results indicated two types of slush-ice berm formation processes: in situ (forming in place) and advective (pushed in by storm winds). Several formation mechanisms were noted for the crystals that compose in situ berms. Cold air temperatures cool the surface of the water, and winds that translate surface cooling through a greater depth aid crystal formation. Snow landing in the water cools via melting of the snow and by contributing crystals directly to the water. A negative surge can expose the wet beach to cold air, allowing crystals to form on the beach, which are then picked up by waves. Slush crystals for advective berm events form offshore. Winds move the slush towards shore, where it accumulates, and wind-induced waves move it up onto the beach.Certaines communautés côtières de l’ouest de l’Alaska observent la présence de « bermes de bouillie de glace ». Généralement parlant, ces bermes se forment au moment de l’engel, lorsque l’eau chargée de cristaux de glace s’empile sur la rive. Les bermes de bouillie de glace peuvent protéger les villages des ondes de tempêtes, tout comme ils peuvent restreindre l’accès à l’eau. Les observations locales à partir de Gambell, Shaktoolik, Shishmaref et Wales ont fait l’objet d’une synthèse afin d’aboutir à une taxonomie des types de bermes de bouillie de glace et à un modèle de processus conceptuel qui décrit comment ils se forment et comment ils se détériorent. Les résultats indiquent deux types de processus de formation des bermes de bouillie de glace : les bermes in situ (formation sur place) et les bermes d’advection (poussés par les vents de tempête). Plusieurs mécanismes de formation ont été notés dans le cas des cristaux qui composent les bermes in situ. Les températures de l’air froid refroidissent la surface de l’eau, et les vents qui transfèrent le refroidissement de la surface à une plus grande profondeur favorisent la formation de cristaux. La neige qui se dépose dans l’eau se refroidit en raison de la fonte de la neige et forme des cristaux directement dans l’eau. Une onde négative peut exposer la plage humide à l’air froid, permettant ainsi aux cristaux de se former sur la plage, et ceux-ci sont ensuite ramassés par les vagues. Dans le cas des bermes d’advection, les cristaux de la bouillie se forment au large. Les vents déplacent la bouillie vers la rive, où elle s’accumule, et les vagues créées par le vent la déposent sur la plage

Effect of suspended sediments on the pumping rates of three species of glass sponge in situ

The largest known glass sponge reefs in Canada are within the Hecate Strait and Queen Charlotte Sound Glass Sponge Reefs Marine Protected Area (HSQCS-MPA) in British Columbia. However, human activities outside the core MPA boundaries, such as trawling, can create plumes of suspended sediments capable of travelling large distances. We studied the response of 3 glass sponge species to changes in suspended sediment concentrations (SSCs) at 170 m depth inside the HSQCS-MPA. Two species reduced excurrent flow rate in response to natural and experimentally induced increases in suspended sediment. Background suspended sediment levels were low and showed little variation (2.71 ± 0.09 mg l-1, mean ± SD). Species varied in the threshold of SSCs that triggered arrests. Sediment concentrations of 2.8-6.4 mg l-1 caused arrests in Rhabdocalyptus dawsoni, while Heterochone calyx did not arrest until concentrations reached 5-10 mg l-1. Very small, but prolonged increases of suspended sediments (<1 mg l-1 for R. dawsoni and 3.2 mg l-1 for H. calyx) caused arrests of several hours in R. dawsoni and prolonged periods of reduced flow in H. calyx. No arrests were observed in Farrea occa, even after repeated exposures up to 57 mg l-1. A sediment transport model showed that sediment concentrations can remain high enough to affect sponge behaviour as far as 2.39 km from the source of the plume. The results highlight the importance of understanding the biology of different species for establishment of adequate boundaries in MPAs.publishedVersio

Effect of timing and abundance of lesser sandeel on the breeding success of a North Sea seabird community

Understanding the responses of seabirds to climate-induced variations in phenology and abundance of their prey is key to developing ecosystem-based fisheries management measures that benefit higher trophic levels. The match/mismatch hypothesis (MMH) emphasizes the need to consider synchrony in the seasonal cycles of predators and prey, while the match/mismatch/abundance hypothesis (MMAH) proposes that prey abundance may reinforce/compensate mismatch effects. This study considers the effects of both variations in seasonal availability and abundance of lesser sandeel Ammodytes marinus on hatching, fledging and breeding success of 5 seabird species: blacklegged kittiwake Rissa tridactyla, Atlantic puffin Fratercula arctica, razorbill Alca torda, common guillemot Uria aalge and European shag Gulosus aristotelis. Consistent with MMH, temporal asynchrony between sandeel availability and seabird breeding schedules affected productivity in 4 species. The effects of trophic asynchrony were either reinforced or compensated by sandeel abundance for some species, supporting MMAH. Breeding success in the late-breeding kittiwake was high when conditions favoured both high sandeel abundance and temporal synchrony while the cost of asynchrony could be compensated by high sandeel abundance in the earlier-breeding puffin. Differential effects of sandeel abundance and trophic synchrony at different stages of the seabird breeding season suggest that distinct mechanisms are in volved. The effects were most evident in the most sandeel-reliant seabirds. As further disruption of sandeel phenology and abundance is anticipated under the current climate crisis, the present study is an important step towards understanding bottom-up effects of environmental change on higher trophic levels

Environmental drivers of a decline in a coastal zooplankton community

Major changes in North Atlantic zooplankton communities in recent decades have been linked to climate change but the roles of environmental drivers are often complex. High temporal resolution data is required to disentangle the natural seasonal drivers from additional sources of variability in highly heterogeneous marine systems. Here, physical and plankton abundance data spanning 2003–2017 from a weekly long-term monitoring site on the west coast of Scotland were used to investigate the cause of an increasing decline to approximately -80± 5% in annual average total zooplankton abundance from 2011 to 2017. Generalized additive mixed models (GAMMs), with an autoregressive correlation structure, were used to examine seasonal and inter-annual trends in zooplankton abundance and their relationship with environmental variables. Substantial declines were detected across all dominant taxa, with ∼ 30–70% of the declines in abundance explained by a concurrent negative trend in salinity, alongside the seasonal cycle, with the additional significance of food availability found for some taxa. Temperature was found to drive seasonal variation but not the long-term trends in the zooplankton community. The reduction in salinity had the largest effect on several important taxa. Salinity changes could partly be explained by locally higher freshwater run-off driven by precipitation as well as potential links to changes in offshore water masses. The results highlight that changes in salinity, caused by either freshwater input (expected from climate predictions) or fresher offshore water masses, may adversely impact coastal zooplankton communities and the predators that depend on them

Fenton's reagent for the rapid and efficient isolation of microplastics from wastewater

Fenton’s reagent was used to isolate microplastics from organic-rich wastewater. The catalytic reaction did not affect microplastic chemistry or size, enabling its use as a pre-treatment method for focal plane array-based micro-FT-IR imaging. Compared with previously described microplastic treatment methods, Fenton’s reagent offers a considerable reduction in sample preparation times

Microplastics as Vectors for Environmental Contaminants : Exploring Sorption, Desorption, and Transfer to Biota

The occurrence and effects of microplastics (MPs) in the aquatic environment are receiving increasing attention. In addition to their possible direct adverse effects on biota, the potential role of MPs as vectors for hydrophobic organic chemicals (HOCs), compared to natural pathways, is a topic of much debate. It is evident, however, that temporal and spatial variations of MP occurrence do (and will) occur. To further improve the estimations of the role of MPs as vectors for HOC transfer into biota under varying MP concentrations and environmental conditions, it is important to identify and understand the governing processes. Here, we explore HOC sorption to and desorption from MPs and the underlying principles for their interactions. We discuss intrinsic and extrinsic parameters influencing these processes and focus on the importance of the exposure route for diffusive mass transfer. Also, we outline research needed to fill knowledge gaps and improve model-based calculations of MP-facilitated HOC transfer in the environment. Integr Environ Assess Manag 2017;13:488–493. © 2017 SETA

Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging

Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.This work is funded by a NERC (Natural Environment Research Council) CASE studentship (NE/K007521/1) with contribution from industrial partner Fera Science Ltd., United Kingdom. The authors would like to thank Peter Vale, from Severn Trent Water Ltd, for providing access to and additionally Ashley Howkins (Brunel University London) for providing travel and assistance with the sampling of the Severn Trent wastewater treatment plant in Derbyshire, UK. We are grateful to Emma Bradley and Chris Sinclair for providing helpful suggestions for our research

Ingestion of marine debris by Wedge-tailed Shearwaters ( Ardenna pacifica ) on Lord Howe Island, Australia during 2005–2018

publisher: Elsevier articletitle: Ingestion of marine debris by Wedge-tailed Shearwaters (Ardenna pacifica) on Lord Howe Island, Australia during 2005–2018 journaltitle: Marine Pollution Bulletin articlelink: https://doi.org/10.1016/j.marpolbul.2018.06.023 content_type: article copyright: © 2018 Elsevier Ltd. All rights reserved.The attached document is the authors’ submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it