Imperial College London

DrErikvan Sebille

Faculty of Natural SciencesThe Grantham Institute for Climate Change

Honorary Lecturer
 
 
 
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Contact

 

e.van-sebille Website

 
 
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Location

 

Sherfield BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

201 results found

Nordam T, Kristiansen R, Nepstad R, van Sebille E, Booth AMet al., 2023, A comparison of Eulerian and Lagrangian methods for vertical particle transport in the water column, Geoscientific Model Development, Vol: 16, Pages: 5339-5363

<jats:p>Abstract. A common task in oceanography is to model the vertical movement of particlessuch as microplastics, nanoparticles, mineral particles, gas bubbles, oildroplets, fish eggs, plankton, or algae. In some cases, the distribution of thevertical rise or settling velocities of the particles in question can span awide range, covering several orders of magnitude, often due to a broadparticle size distribution or differences in density. This requiresnumerical methods that are able to adequately resolve a wide and possiblymulti-modal velocity distribution. Lagrangian particle methods are commonly used for these applications. Astrength of such methods is that each particle can have its own rise orsettling speed, which makes it easy to achieve a good representation of acontinuous distribution of speeds. An alternative approachis to use Eulerian methods, where the partial differential equationsdescribing the transport problem are solved directly with numerical methods.In Eulerian methods, different rise or settling speeds must be representedas discrete classes, and in practice, only a limited number of classes can beincluded. Here, we consider three different examples of applications for awater column model: positively buoyant fish eggs, a mixture of positivelyand negatively buoyant microplastics, and positively buoyant oil dropletsbeing entrained by waves. For each of the three cases, we formulate a modelfor the vertical transport based on the advection–diffusion equation withsuitable boundary conditions and, in one case, a reaction term. We give adetailed description of an Eulerian and a Lagrangian implementation of thesemodels, and we demonstrate that they give equivalent results for selectedexample cases. We also pay special attention to the convergence of the modelresults with an increasing number of classes in the Eulerian scheme and with thenumber of particles in the Lagrangian scheme. For the Lagrangian scheme, wesee the 1/Np convergence, as exp

Journal article

Nooteboom PD, Scutt Phillips J, Senina I, Van Sebille E, Nicol Set al., 2023, Individual-based model simulations indicate a non-linear catch equation of drifting Fish Aggregating Device-Associated tuna, ICES Journal of Marine Science, Vol: 80, Pages: 1746-1757, ISSN: 1054-3139

Catch per unit of fishing effort (CPUE) is often used as an indicator of tuna abundance, where it is assumed that the two are proportional to each other. Tuna catch is therefore typically simplified in tuna population dynamics models and depends linearly on their abundance. In this paper, we use an individual-based model of tuna and their interactions with drifting Fish Aggregating Devices (dFADs) to identify which behavioural, ocean flow, and fishing strategy scenarios lead to an emergent, non-linear dependency between catch, and both tuna and dFAD density at the ∼1 grid scale. We apply a series of catch response equations to evaluate their ability to model associated catch rate, using tuna and dFAD density as terms. Our results indicate that, regardless of ocean flow, behavioural, or fisher strategy scenario, simulated catch is best modelled with a non-linear dependence on both tuna and dFAD abundance. We discuss how estimators of CPUE at the population scale are potentially biased when assuming a linear catch response.

Journal article

Kehl C, Nooteboom PD, Kaandorp MLA, van Sebille Eet al., 2023, Efficiently simulating Lagrangian particles in large-scale ocean flows — Data structures and their impact on geophysical applications, Computers and Geosciences, Vol: 175, ISSN: 0098-3004

Studying oceanography by using Lagrangian simulations has been adopted for a range of scenarios, such as the determining the fate of microplastics in the ocean, simulating the origin locations of microplankton used for palaeoceanographic reconstructions, and for studying the impact of fish aggregation devices on the migration behaviour of tuna. These simulations are complex and represent a considerable runtime effort to obtain trajectory results, which is the prime motivation for enhancing the performance of Lagrangian particle simulators. This paper assesses established performance enhancing techniques from Eulerian simulators in light of computational conditions and demands of Lagrangian simulators. A performance enhancement strategy specifically targeting physics-based Lagrangian particle simulations is outlined to address the performance gaps, and techniques for closing the performance gap are presented and implemented. Realistic experiments are derived from three specific oceanographic application scenarios, and the suggested performance-enhancing techniques are benchmarked in detail, so to allow for a good attribution of speed-up measurements to individual techniques. The impacts and insights of the performance enhancement strategy are further discussed for Lagrangian simulations in other geoscience applications. The experiments show that I/O-enhancing techniques, such as dynamic loading and buffering, lead to considerable speed-up on-par with an idealised parallelisation of the process over 20 nodes. Conversely, while the cache-efficient structure-of-arrays collection yields a visible speed-up, other alternative data structures fail in fulfilling the theoretically-expected performance increase. This insight demonstrates the importance of good data alignment in memory and caches for Lagrangian physics simulations.

Journal article

Rühs S, van Sebille E, Moulin A, Clementi Eet al., 2023, Impact of the representation of waves on simulated particle dispersal in the surface ocean

<jats:p>The knowledge of how seawater moves around in the global ocean and transports tracers and particulates, is crucial for solving many outstanding issues in physical oceanography and climate science. Due to limited available observations, seawater pathways are often estimated by evaluating virtual particle trajectories inferred from velocity fields computed with ocean models. The quality of these Lagrangian analyses strongly depends on how well the underlying ocean model represents the ocean circulation features of interest.Here, we investigate how simulated surface particle dispersal changes, if the &amp;#8211; often omitted or only approximated &amp;#8211; impact of surface waves is considered. Specifically, we test the impact of new representations of wave-current interactions for the ocean model NEMO in a case study for the Mediterranean Sea. We are using velocity output from a high-resolution (1/24&amp;#176;) ocean-only model simulation as well as a complementary coupled ocean-wave model simulation, to answer the following questions: How do waves impact the simulated surface particle dispersal, and what is the relative impact of Stokes drift and wave-driven Eulerian currents? How well can the wave impact be approximated by the superposition of Eulerian mean and Stokes drift velocity fields obtained from independently run ocean and wave models?We find that the wave coupling leads to a decrease in the mean surface current speed in summer dominated by wave-driven Eulerian currents, and an increase in the mean surface current speed in winter dominated by Stokes drift. We further show that Lagrangian simulations with superimposed Eulerian currents and Stokes drift from independent ocean-only and wave models do not necessarily yield more realistic results for surface dispersal patterns than simulations that do not include any wave effect. This implies that &amp;#8211; whenever possible &amp;#8211; velocity fields from a coupled ocean-wa

Other

Reijnders D, Bakker D, van Sebille E, 2023, Lagrangian Spatiotemporal Fingerprints of Dissolved Inorganic Carbon in Eighteen Degree Water Formation

<jats:p>Mode waters are defined as thick, weakly stratified layers with homogeneous properties. They have the ability to store these properties, such as heat, carbon and nutrients, and exchange these with the surface or atmosphere during outcropping events or with other layers via mixing processes. Eighteen Degree Water (EDW) is the subtropical mode water of the western North Atlantic. Its yearly outcropping events in late winter makes it an important regulator of ocean heat, nutrients and carbon in the North Atlantic on annual timescales.Previous studies have given insight into the formation and destruction of Eighteen Degree Water. These have largely focused on physical aspects such as EDW formation rates. Due to the importance of EDW formation in setting the biogeochemical environment in the North Atlantic, it is instructive to investigate how biogeochemical tracers are altered along EDW formation routes. This study investigates in particular how dissolved inorganic carbon (DIC) is altered along ocean water parcel trajectories as EDW is formed. To do so, we compute Lagrangian trajectories of subducted EDW backwards in time using a coupled hydrodynamic and biogeochemical model. By sampling biogeochemical tracer values along Lagrangian pathways, we construct timeseries which we use to map the dominant locations at which DIC concentrations are altered in space and time to identify the Lagrangian fingerprint of DIC in Eighteen Degree Water.</jats:p>

Other

Pierard C, van Sebille E, 2023, Identifying the Origins of PET Nanoplastics in the Abyssal South Atlantic Using Backtracking Lagrangian Simulations with Fragmentation

<jats:p>During an expedition in January 2020, nanoplastics were sampled at a depth of -5170m over Cape Basin in the South Atlantic Ocean. Using photo-induced force microscopy, it was identified that these were polyethylene terephthalate (PET) particles with an approximate diameter of 50 nm at different stages of degradation. Using a state-of-the-art Lagrangian 3D simulation that includes an idealized fragmentation scheme, we backtracked virtual particles from the sampling location to establish the possible origins of the PET nanoplastics. We performed several simulations with different fragmenting timescales, for 13 years from the date of sampling, using the GLO12V3R1 hydrodynamic data from Copernicus Marine Environment Monitoring Service. We found that the nanoparticles (smaller than 1&amp;#956;m) could not have fragmented into nanoplastics at the surface and reached the sampling location within 13 years. The most likely scenario is that these particles started to sink from the surface as microplastics (larger than 1&amp;#956;m) and then fragmented in the water column far from the surface. This suggests that the fragmentation happened through processes like slow thermal oxidative degradation or hydrolysis and not photodegradation. We also found that less than 0.2% of the virtual particles came from the coast and that the fragmentation timescale prescribed to the modelled particles, affects how they drift in the ocean by controlling the time they drift at different depths. This study contributes to understanding the fate and sources of nanoplastics suspended deep in the ocean.</jats:p>

Other

Guerrini F, Lobelle D, Mari L, Casagrandi R, van Sebille Eet al., 2023, Modeling carbon export mediated by biofouled microplastics in the Mediterranean Sea, Limnology and Oceanography, Vol: 68, Pages: 1078-1090

Marine microplastics can be colonized by biofouling microbial organisms, leading to a decrease in microplastics' buoyancy. The sinking of biofouled microplastics could therefore represent a novel carbon export pathway within the ocean carbon cycle. Here, we model how microplastics are biofouled by diatoms, their consequent vertical motion due to buoyancy changes, and the interactions between particle-attached diatoms and carbon pools within the water column. We initialize our Lagrangian framework with biogeochemical data from NEMO-MEDUSA-2.0 and estimate the amount of organic carbon exported below 100 m depth starting from different surface concentrations of 1-mm microplastics. We focus on the Mediterranean Sea that is characterized by some of the world's highest microplastics concentrations and is a hotspot for biogeochemical changes induced by rising atmospheric carbon dioxide levels. Our results show that the carbon export caused by sinking biofouled microplastics is proportional to the concentration of microplastics in the sea surface layer, at least at modeled concentrations. We estimate that, while current concentrations of microplastics can modify the natural biological carbon export by < 1%, future concentrations projected under business-as-usual pollution scenarios may lead to carbon exports up to 5% larger than the baseline (1998–2012) by 2050. Areas characterized by high primary productivity, that is, the Western and Central Mediterranean, are those where microplastics-mediated carbon export results to be the highest. While highlighting the potential and quantitatively limited occurrence of this phenomenon in the Mediterranean Sea, our results call for further investigation of a microplastics-related carbon export pathway in the global ocean.

Journal article

Onink V, Kaandorp MLA, van Sebille E, Laufkoetter Cet al., 2022, Influence of Particle Size and Fragmentation on Large-Scale Microplastic Transport in the Mediterranean Sea, ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 56, Pages: 15528-15540, ISSN: 0013-936X

Journal article

Ypma SL, Bohte Q, Forryan A, Garabato ACN, Donnelly A, van Sebille Eet al., 2022, Detecting the most effective cleanup locations using network theory to reduce marine plastic debris: a case study in the Galapagos Marine Reserve, OCEAN SCIENCE, Vol: 18, Pages: 1477-1490, ISSN: 1812-0784

Journal article

Nooteboom PD, Scutt Phillips J, Kehl C, Nicol S, van Sebille Eet al., 2022, Modelling of tuna around fish aggregating devices: the importance of ocean flow and prey

<jats:title>Abstract</jats:title><jats:p>Catch and distribution of tuna in the ocean are typically investigated with ocean basin-scale models. Due to their large scale, such models must greatly simplify tuna behaviour occurring at a scale below ∼100 km, despite interactions at this level potentially being important to both catch and distribution of tuna. For example, the associative behaviour of tuna with man-made floating objects, that are deployed by fishers to improve their catch rates (Fish Aggregating Devices; FADs), are usually ignored or simplified. Here we present a model that can be used to investigate the influence of tuna dynamics below the ∼100 km scale on larger scales. It is an Agent-Based Model (ABM) of a hypothetical, tuna-like species, that includes their interactions with each other, free-floating FADs and prey. In this ABM, both tuna and FADs are represented by Lagrangian particles that are advected by an ocean flow field, with tuna also exhibiting active swimming based on internal states such as stomach fullness. We apply the ABM in multiple configurations of idealised flow and prey fields, alongside differing interaction strengths between agents. When tuna swimming behaviour is influenced equally by prey and FADs, we find that the model simulations compare well with observations at the ≲ 100 km scale. For instance, compared to observations, tuna particles have a similar stomach fullness when associated or non-associated to a FAD, tuna colonize at similar timescales at FADs after their deployment and tuna particles exhibit similar variations in continuous residence times. However, we find large differences in emergent dynamics such as residence and catch among different flow configurations, because the flow determines the time scale at which tuna encounter FADs. These findings are discussed in the context of directing future research, and an improved interpretation of tuna catch and other data for the sustainable managem

Journal article

Gomez-Navarro L, Van Sebille E, MORALES MÁRQUEZ V, Hernandez-Carrasco I, Albert A, Ubelmann C, Le Sommer J, Molines J-M, Brodeau Let al., 2022, The effect of model tidal forcing on virtual particle dispersion and accumulation at the ocean surface

Journal article

Nooteboom PD, Baatsen M, Bijl PK, Kliphuis MA, van Sebille E, Sluijs A, Dijkstra HA, von der Heydt ASet al., 2022, Improved Model-Data Agreement With Strongly Eddying Ocean Simulations in the Middle-Late Eocene, PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY, Vol: 37, ISSN: 2572-4517

Journal article

Christensen AK, Piggott MD, van Sebille E, van Reeuwijk M, Pawar Set al., 2022, Investigating microscale patchiness of motile microbes under turbulence in a simulated convective mixed layer., PLoS Comput Biol, Vol: 18

Microbes play a primary role in aquatic ecosystems and biogeochemical cycles. Spatial patchiness is a critical factor underlying these activities, influencing biological productivity, nutrient cycling and dynamics across trophic levels. Incorporating spatial dynamics into microbial models is a long-standing challenge, particularly where small-scale turbulence is involved. Here, we combine a fully 3D direct numerical simulation of convective mixed layer turbulence, with an individual-based microbial model to test the key hypothesis that the coupling of gyrotactic motility and turbulence drives intense microscale patchiness. The fluid model simulates turbulent convection caused by heat loss through the fluid surface, for example during the night, during autumnal or winter cooling or during a cold-air outbreak. We find that under such conditions, turbulence-driven patchiness is depth-structured and requires high motility: Near the fluid surface, intense convective turbulence overpowers motility, homogenising motile and non-motile microbes approximately equally. At greater depth, in conditions analogous to a thermocline, highly motile microbes can be over twice as patch-concentrated as non-motile microbes, and can substantially amplify their swimming velocity by efficiently exploiting fast-moving packets of fluid. Our results substantiate the predictions of earlier studies, and demonstrate that turbulence-driven patchiness is not a ubiquitous consequence of motility but rather a delicate balance of motility and turbulent intensity.

Journal article

Ypma SL, Bohte Q, Forryan A, Naveira Garabato AC, Donnelly A, van Sebille Eet al., 2022, Detecting most effective cleanup locations using network theory to reduce marine plastic debris: A case study in the Galapagos Marine Reserve

<jats:p>Abstract. The Galapagos Marine Reserve was established in 1986 to ensure protection of the islands' unique biodiversity. Unfortunately, the islands are polluted by marine plastic debris and the island authorities face the challenge to effectively remove plastic from its shorelines due to limited resources. To optimise efforts, we have identified the most effective cleanup locations on the Galapagos Islands using network theory. A network is constructed from a Lagrangian simulation describing the flow of macroplastic between the various islands within the Galapagos Marine Reserve, where the nodes represent locations along the coastline and the edges the likelihood for plastic to travel from one location and beach at another. We have found four network centralities that provide the best coastline ranking to optimise the cleanup effort based on various impact metrics. In particular locations with a high retention rate are favourable for cleanup. The results indicate that using the most effective centrality for finding cleanup locations is a good strategy for heavily polluted regions if the distribution of marine plastic debris on the coastlines is unknown and limited cleanup resources are available. </jats:p>

Journal article

Bergmann M, Collard F, Fabres J, Gabrielsen GW, Provencher JF, Rochman CM, van Sebille E, Tekman MBet al., 2022, Plastic pollution in the Arctic (vol 3, pg 323, 2022), NATURE REVIEWS EARTH & ENVIRONMENT, Vol: 3, Pages: 420-420

Journal article

Valles-Casanova I, Fraile-Nuez E, Martin-Rey M, van Sebille E, Cabre A, Olive-Abello A, Pelegri JLet al., 2022, Water Mass Transports and Pathways in the North Brazil-Equatorial Undercurrent Retroflection, JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, Vol: 127, ISSN: 2169-9275

Journal article

Fischer R, Lobelle D, Kooi M, Koelmans A, Onink V, Laufkoetter C, Amaral-Zettler L, Yool A, van Sebille Eet al., 2022, Modelling submerged biofouled microplastics and their vertical trajectories, BIOGEOSCIENCES, Vol: 19, Pages: 2211-2234, ISSN: 1726-4170

Journal article

Bergmann M, Collard F, Fabres J, Gabrielsen GW, Provencher JF, Rochman CM, van Sebille E, Tekman MBet al., 2022, Plastic pollution in the Arctic, NATURE REVIEWS EARTH & ENVIRONMENT, Vol: 3, Pages: 323-337

Journal article

Bertoncelj V, Stocchi P, Holzhauser C, Sánchez Barranco V, Alcantar E, Candy A, Haas A, Mienis F, de Nooijer L, van Sebille E, Vermeij Met al., 2022, Assessing hydrodynamic processes of nearshore coral reefs: numerical modeling and field observations around the island of Cura&amp;#231;ao

<jats:p>&amp;lt;p&amp;gt;The state of coral reef ecosystems is highly dependent on the availability and ratio of essential resources such as oxygen, minerals and nutrients, and the presence of pollutants, pathogens and other possible stressors. The distribution of these inputs is dynamic and depends on many factors, including the nearshore hydrodynamic processes. These are unique processes, consisting of tidal pumping, nearshore circulation, and wave action. Furthermore, these processes are highly influenced by complex reef bathymetry and the physical roughness of the reef. The latter has a crucial role in the boundary layer characteristics, which influences uptake by reef organisms at smaller spatial scales.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The understanding of distribution and transport of particulate and dissolved substances is challenging as field surveys are difficult to perform and there is a large variety of coral shapes. However, assessing the hydrodynamic processes is a necessary first step in order to link the sources and sinks of substances with the coral health and growth. Within the interdisciplinary research program SEALINK, we aim to assess the distribution and pathways of substances around the island of Cura&amp;amp;#231;ao. Field observations on selected sites along the coast of Cura&amp;amp;#231;ao include current and wave measurements with Acoustic Doppler Current Profilers and flow visualization with fluorescent dye.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We will present preliminary results from the field campaign showing velocity fields and wave transformation on different stations along the cross-shore transects on the reef platform. Using a combination of field observations and 3D non-hydrostatic Computational Fluid Dynamics models, we investigate the mixing mechanisms and local energy balance at scales of O(10 m) on the selected reef quadrants. This serves as a basis for a further analysis wit

Journal article

Kaandorp M, Lobelle D, Kehl C, van Sebille Eet al., 2022, A global 3D map of marine plastic litter: a data assimilated modelling framework &amp;#160;

<jats:p>&amp;lt;p&amp;gt;Estimates of plastic quantities entering our oceans are not yet consistent with observed concentrations in the marine environment. This has led to the often-quoted statement that 99% of the marine plastics are missing. Here, we present a framework where the global transport of marine plastics is modelled over long time scales, in which the effects of different sources and sinks is investigated. Data assimilation techniques are used to inform unknown parameters regarding these sources and sinks, enabling us to quantify their role on the global plastic mass budget.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;State-of-the-art numerical models are included in the framework to capture for the first time the combined effect of marine plastic beaching, resuspension, biofouling, turbulent mixing, and fragmentation. The relative importance of different marine plastic sources is investigated, such as mismanaged coastal plastic waste, riverine outflow, and fishing activity. Unknown parameters are found by means of calibration to a large set of observational data of plastic concentrations in the ocean surface water, water column, ocean floor, and on coastlines.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We show that with this framework, the global marine plastic mass budget can be closed. An overview is given of which environmental reservoirs are likely to contain most of the plastic mass, which sources are contributing to most of the pollution, and what the residence times of litter in the marine environment is. With the model calibration approach, we additionally get a better insight in the physics governing the transport of marine litter.&amp;amp;#160;&amp;lt;/p&amp;gt;</jats:p>

Journal article

Manral D, Amaral-Zettler L, van Sebille E, 2022, Lagrangian connectivity of marine plankton under thermal constraints

<jats:p>&amp;lt;p&amp;gt;The biogeographic distribution of marine planktonic communities in the global ocean and its drivers has been a topic of great interest in the scientific community. Some of these drivers can be abiotic: ocean currents, temperature, salinity, nutrients, and others biotic: presence of predators and competitive species. In our study, we focus on the distribution mediated by ocean currents and temperature. Combining Lagrangian modeling and network theory approaches, we estimate the pathways and timescales that establish the surface connectivity for passive i.e., freely floating plankton between stations in the Atlantic Ocean where plankton have been sampled during &amp;lt;em&amp;gt;Tara Oceans &amp;amp; Tara Oceans Polar Circle&amp;lt;/em&amp;gt; (2009-2013) and &amp;lt;em&amp;gt;Tara Pacific&amp;lt;/em&amp;gt; (2016-2018) expeditions.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;We obtain these estimates using a transition matrix approach derived from surface ocean simulations. Given the high rates of reproduction of many planktonic species and that only a few organisms are needed to establish connectivity, we make use of the minimum time path between different stations. To obtain plankton connectivity, two types of constraints are applied on the passive connectivity model: &amp;lt;em&amp;gt;thermal niche&amp;lt;/em&amp;gt; and &amp;lt;em&amp;gt;thermal adaptation rate&amp;lt;/em&amp;gt;, based on data for a given planktonic species from the literature. From the preliminary analysis, we find that, using minimum time paths, passive particles representative of foraminifera can connect all the stations in less than 3 years. Application of thermal niche constraints increases the minimum connectivity time between stations by approximately 10%, suggesting that plankton can keep to within their favorable thermal conditions by advecting via slightly longer paths. Main

Journal article

Reijnders D, van Sebille E, Bijl P, 2022, KlimaatHelpdesk.org: Connecting citizens with climate questions to experts with answers&amp;#160;

<jats:p>&amp;lt;div&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;When faced with a question, scientists and scholars are trained to&amp;amp;#160;search&amp;amp;#160;academic and informal&amp;amp;#160;literature to find&amp;amp;#160;the answer.&amp;amp;#160;But where&amp;amp;#160;can&amp;amp;#160;the public&amp;amp;#160;find reliable&amp;amp;#160;answers to&amp;amp;#160;questions about the climate crisis?&amp;amp;#160;After all,&amp;amp;#160;the climate crisis&amp;amp;#160;is a topic about which our understanding&amp;amp;#160;rapidly&amp;amp;#160;evolves&amp;amp;#160;across a wide array of disciplines.&amp;amp;#160;The validity&amp;amp;#160;and reliability&amp;amp;#160;of&amp;amp;#160;offered&amp;amp;#160;information is difficult to&amp;amp;#160;assess&amp;amp;#160;for non-specialists, while scientific consensus is&amp;amp;#160;sometimes deliberately undermined&amp;amp;#160;in popular articles. Moreover,&amp;amp;#160;civil&amp;amp;#160;questions about&amp;amp;#160;the&amp;amp;#160;climate&amp;amp;#160;crisis&amp;amp;#160;can be very specific, pragmatic or locally applicable, so not all answers can be found on popular sources&amp;amp;#160;that&amp;amp;#160;commonly&amp;amp;#160;provide only the theoretical principles or general background.&amp;amp;#160;This raises the question how we can connect citizens with climate-related questions to understandable scientific expert&amp;amp;#160;&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;knowledge&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;.&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt;&amp;lt;/div&amp;gt;&amp;lt;div&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;KlimaatHelpdesk.org&amp;amp;#160;is meant to become the go-to place in the Netherlands for&amp;amp;#160;citizens&amp;amp;#16

Journal article

Ypma S, Bohte Q, Jones J, Donnelly A, van Sebille Eet al., 2022, Detecting most effective coastal plastic clean-up hubs using network theory: a case study in the Galapagos Marine Reserve&amp;#160;

<jats:p>&amp;lt;p&amp;gt;Over 8 tonnes of plastic are removed from the coastlines of the Galapagos Islands each year. Although the Galapagos Marine Reserve is expanding to ensure an even larger protection of its unique biodiversity, the island authorities face the challenge to effectively remove plastic from its shorelines due to limited resources. We are developing a clean-up efficacy model that will optimize for most cost-effective and least-invasive clean-up locations. Network (connectivity) theory is widely applied in ecology to study the interaction of species between spatially separated habitats. Here, we use a similar approach to discern the most effective removal hubs on the Galapagos Islands. A connectivity matrix is constructed from a Lagrangian simulation describing the flow of macroplastic between the various islands within the Galapagos Marine Reserve, where the nodes represent locations along the coastline and the edges the likelihood that plastic travels from one location and beaches at another. To measure the impact of removal, various centralities are determined, such as degree centrality, betweenness centrality (using the most likely path) and eigenvector centrality. Combining the results with other metrics such as the distance to the nearest port or tourist attractions, recommendations are made for&amp;lt;/p&amp;gt;&amp;lt;ul&amp;gt;&amp;lt;li&amp;gt;most effective &amp;lt;em&amp;gt;intervention&amp;lt;/em&amp;gt; removal hubs that would prevent further spread of plastic throughout the marine reserve&amp;lt;/li&amp;gt;&amp;lt;li&amp;gt;most effective &amp;lt;em&amp;gt;accumulation&amp;lt;/em&amp;gt; removal hubs that would negate the impact of plastic on wildlife&amp;lt;/li&amp;gt;&amp;lt;li&amp;gt;most suited regions for protection resulting from the existence of clusters (e.g. regions of limited connectivity)&amp;lt;/li&amp;gt;&amp;l

Journal article

Reijnders D, Deleersnijder E, van Sebille E, 2022, Lagrangian Ocean Ventilation: Improved Subgrid-Scale Dispersion on Neutral Surfaces

<jats:p>&amp;lt;p&amp;gt;Mesoscale eddies play a major role in ocean ventilation by stirring ocean tracers, such as carbon, along sloping surfaces of neutral buoyancy. To capture the effects of these turbulent eddies, coarse resolution ocean models resort to tracer diffusion parameterizations that take into account neutral surface slopes. Likewise, when studying tracer pathways in a Lagrangian framework, the effect of eddy dispersion needs to be parameterized when coarse models are used.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Dispersion in Lagrangian simulations is traditionally parameterized by random walks, equivalent to diffusion in Eulerian models. Beyond random walks, there is a hierarchy of stochastic parameterizations, where stochastic perturbations are added to Lagrangian particle velocities, accelerations, or hyper-accelerations. These parameterizations are referred to as the 1&amp;lt;sup&amp;gt;st&amp;lt;/sup&amp;gt;, 2&amp;lt;sup&amp;gt;nd&amp;lt;/sup&amp;gt; and 3&amp;lt;sup&amp;gt;rd&amp;lt;/sup&amp;gt; order &amp;amp;#8216;Markov models&amp;amp;#8217; (Markov-N&amp;lt;em&amp;gt;)&amp;lt;/em&amp;gt; respectively. Most previous studies investigate these parameterizations in two-dimensional setups, often restricted to the ocean surface. The few studies that investigated Lagrangian dispersion parameterizations on three-dimensional neutral surfaces have focused only on random walk (Markov-0) dispersion.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Here, we present a three-dimensional isoneutral formulation of the Markov-1 model. We also implement an anisotropic, shear-dependent formulation of Lagrangian random walk dispersion, originally formulated as a Eulerian diffusion parameterization by Le Sommer et al (2011). Random walk dispersion and Markov-1 are compared using an idealized setup as well as more realistic coarse and coarsened (50 km) ocean model out

Journal article

Onink V, van Sebille E, Laufkotter C, 2022, Empirical Lagrangian parametrization for wind-driven mixing of buoyant particles at the ocean surface, GEOSCIENTIFIC MODEL DEVELOPMENT, Vol: 15, Pages: 1995-2012, ISSN: 1991-959X

Journal article

Kaandorp MLA, Ypma SL, Boonstra M, Dijkstra HA, van Sebille Eet al., 2022, Using machine learning and beach cleanup data to explain litter quantities along the Dutch North Sea coast, OCEAN SCIENCE, Vol: 18, Pages: 269-293, ISSN: 1812-0784

Journal article

Rice A, Nooteboom PD, Sebille E, Peterse F, Ziegler M, Sluijs Aet al., 2022, Limited Lateral Transport Bias During Export of Sea Surface Temperature Proxy carriers in the Mediterranean Sea, GEOPHYSICAL RESEARCH LETTERS, Vol: 49, ISSN: 0094-8276

Journal article

van Duinen B, Kaandorp MLA, van Sebille E, 2022, Identifying Marine Sources of Beached Plastics Through a Bayesian Framework: Application to Southwest Netherlands, GEOPHYSICAL RESEARCH LETTERS, Vol: 49, ISSN: 0094-8276

Journal article

Nooteboom PD, Bijl PK, Kehl C, van Sebille E, Ziegler M, von der Heydt AS, Dijkstra HAet al., 2022, Sedimentary microplankton distributions are shaped by oceanographically connected areas, EARTH SYSTEM DYNAMICS, Vol: 13, Pages: 357-371, ISSN: 2190-4979

Journal article

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