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The importance of long-time series of benthic data for science and management
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Benthic organisms are important ecological receptors, playing fundamental roles across seafloor ecosystems, delivering some of the most important functions in the marine environment. Some of these key benthic functions include nutrient cycling, food provision for higher trophic levels, and carbon storage. Over the past 6 years, benthic monitoring has faced growing complexity, driven by diminishing funding and the constraints imposed by the COVID-19 pandemic. These challenges underscore the pressing need to recognize the enduring value of benthic time series in supporting monitoring, management, and modelling efforts. These long-term data sets have been critical to advance our current understanding into the areas of cumulative effects, conservation, management of Marine Protected Areas (MPAs), development of indicators, and assessment of climate-driven changes in marine ecosystems. Ongoing expert group discussions consistently affirm both the relevance and necessity of continuing to collect these vital data sets. However, the focus on emerging technologies and so-called ‘cutting-edge’ approaches sometimes leads to the undervaluation and compromising some of these long-term series. We contend that a comprehensive understanding of benthic ecology, essential for robust marine management, reliable numerical analysis, and taxonomic consistency, cannot be achieved without the continuity provided by long-term data. Such time series are indispensable for tracking patterns of change and assessing responses across diverse human activities and seafloor ecosystems. While our research has concentrated on soft sediment environments, many of the key principles and recommendations outlined here are broadly applicable to other ecosystem types.
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RBINS Staff Publications 2026
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Magmatic, Magmatic-Hydrothermal, and Deformational Mineral Evolution of Spodumene Pegmatites from the Musha-Ntunga Area (Rwanda)
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Pegmatites in the Mesoproterozoic Karagwe-Ankole belt of Central Africa are associated with large granitic complexes that were emplaced around 1 Ga. This study analyzes drill core samples of fresh albite-spodumene pegmatites from the Musha-Ntunga area (East Rwanda), spatially associated with the Lake Muhazi granitic pluton. We combine petrographic and cathodoluminescence microscopy with Raman spectroscopy and elemental geochemistry to study the paragenetic sequence, microtextural variations, and lithium distribution, from the magmatic and magmatic-hydrothermal stages to the hydrothermal stage and during deformation processes. Five textural types of spodumene are distinguished. Coarse-grained spodumene type 1 and symplectitic type 2 are interpreted to have formed during primary magmatic crystallization, whereas spodumene types 3 and 4 formed during magmatic-hydrothermal alteration. Deformation locally affected the pegmatite intrusions. Spodumene type 1 crystals deformed in a brittle and ductile manner, displaying sigma-clast-shaped porphyroclasts (“spodumene fish”) and boudinage textures. The large strained spodumene crystals were also partially recrystallized to fine-grained elongated crystals (type 5), which occur in bands along with mica, quartz, and apatite and define the main orientation of foliation. Montebrasite occurs both as a late primary magmatic phase with spodumene and as a secondary phase that recrystallized during magmatic-hydrothermal alteration and deformation. Eucryptite, lithiophilite, and cookeite occur as late-stage hydrothermal phases, replacing primary lithium assemblages. Associated phases muscovite, apatite, microcline, albite, quartz, and columbite-tantalite further demonstrate the transition from a magmatic to a (magmatic-)hydrothermal and deformational regime. Elevated lithium contents in tourmaline within the metasedimentary host rock indicate dispersion of lithium into the host rock during pegmatite emplacement, subsequent crystallization, and alteration. The results of this multimethod approach demonstrate that different generations of lithium-bearing minerals and associated textures not only record the full transition from a magmatic to hydrothermal regime but also document deformation-related processes that can impact the distribution of metals within pegmatites.
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RBINS Staff Publications 2025
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Generation of super-resolution gap-free ocean colour satellite products using data-interpolating empirical orthogonal functions (DINEOF)
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In this work we present a super-resolution approach for deriving high-spatial-resolution and high-temporal-resolution ocean colour satellite datasets. The technique is based on DINEOF (data-interpolating empirical orthogonal functions), a data-driven method that uses the spatio-temporal coherence of analysed datasets to infer missing information. DINEOF is used here to effectively increase the spatial resolution of satellite data and is applied to a combination of Sentinel-2 and Sentinel-3 datasets. The results show that DINEOF is able to infer the spatial variability observed in the Sentinel-2 data to the Sentinel-3 data while reconstructing missing information due to clouds and reducing the amount of noise in the initial dataset. In order to achieve this, the Sentinel-2 and Sentinel-3 datasets have undergone the same pre-processing, including a comprehensive, region-independent, and pixel-based automatic switching scheme for choosing the most appropriate atmospheric correction and ocean colour algorithm to derive in-water products. The super-resolution DINEOF has been applied to two different variables (turbidity and chlorophyll) and two different domains (Belgian coastal zone and the whole of the North Sea), and the sub-mesoscale variability of the turbidity along the Belgian coastal zone has been studied.
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RBINS Staff Publications 2025
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A generalized physics-based correction for adjacency effects
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Atmospheric scattering occurs over a horizontal scale of several kilometers. This results in influence from neighboring surface features on the signal recorded over a given position, reducing contrast and the accuracy of quantitative retrievals of surface reflectance from satellite imagery. This atmospheric blurring, or adjacency effect, must be accounted for when both contrast in surface reflectance and magnitude of atmospheric scattering are significant. Taking into account the adjacency effect is of particular importance for aquatic remote sensing of inland and coastal waters due to the high contrast between water and different land cover types, as well as the small spatial scale of most inland water bodies. In this paper, we present a physics-based processor to retrieve surface reflectance over all surface types, regardless of the subscene composition and sensor waveband configuration. The processor is implemented in the free and open source ACOLITE software and is composed of two modules: (1) TSDSF for the estimation of aerosol properties and (2) RAdCor for the retrieval of surface reflectance. We demonstrate the performance of the TSDSF $+$ RAdCor processor for the Operational Land Imager (OLI) onboard Landsat 8 and the Multispectral Instrument (MSI) onboard Sentinel-2A and 2B over a set of small ($\lt1\;\rm km^2$) inland waters in Belgium, and compare the performance with other common processors for these sensors, including C2RCC, POLYMER, Sen2Cor, iCOR, ACOLITE/DSF, and LaSRC. For clear sky matchups, the relative deviation againstin situ data in the visible wavebands ranged between 6% and 18% for OLI, and between 14% and 31% for MSI, except for the MSI waveband centered at 443 nm where the relative deviation was 70%. In the near-infrared wavebands, the relative deviation varied from 70% to 150%, with the exception of the MSI waveband centered at 704 nm, for which the performance was 17%. Overall, the new processor outperformed the other evaluated processors in the visible range, with the exception of the MSI waveband centered at 443 nm, and was outperformed by C2RCC and POLYMER in the near-infrared wavebands. Recommendations on how to use TSDSF and RAdCor in ACOLITE are provided.
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RBINS Staff Publications 2025
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Atmospheric Correction Inter-Comparison eXercise, ACIX-III Land: An Assessment of Atmospheric Correction Processors for EnMAP and PRISMA over Land
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Correcting atmospheric effects on hyperspectral optical satellite scenes is paramount to ensuring the accuracy of derived bio-geophysical products. The open-access benchmark Atmospheric Correction Inter-comparison eXercise (ACIX) was first initiated in 2016 and has now been extended to provide a comprehensive assessment of atmospheric processors of space-borne imaging spectroscopy missions (EnMAP and PRISMA) over land surfaces. The exercise contains 90 scenes, covering stations of the Aerosol Robotic Network (AERONET) for assessing aerosol optical depth (AOD) and water vapour (WV) retrievals, as well as stationary networks (RadCalNet and HYPERNETS) and ad hoc campaigns for surface reflectance (SR) validation. AOD, WV, and SR retrievals were assessed using accuracy, precision, and uncertainty metrics. For AOD retrieval, processors showed a range of uncertainties, with half showing overall uncertainties of <0.1 but going up to uncertainties of almost 0.4. WV retrievals showed consistent offsets for almost all processors, with uncertainty values between 0.171 and 0.875 g/cm2. Average uncertainties for SR retrievals depend on wavelength, processor, and sensor (uncertainties are slightly higher for PRISMA), showing average values between 0.02 and 0.04. Although results are biased towards a limited selection of ground measurements over arid regions with low AOD, this study shows a detailed analysis of similarities and differences of seven processors. This work provides critical insights for understanding the current capabilities and limitations of atmospheric correction algorithms for imaging spectroscopy, offering both a foundation for future improvements and a first practical guide to support users in selecting the most suitable processor for their application needs.
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RBINS Staff Publications 2025
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Diagnosing the Flocculation–Transport Dynamics of Suspended Particulate Matter Using a Two-Class Population Balance Model and Bayesian Calibration
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Abstract The dynamics of suspended particulate matter (SPM) plays a crucial role in determining water quality, sediment transport, and biogeochemical cycles in inland, estuarine, and coastal water resources. Flocculation processes strongly influence the SPM dynamics via aggregation and breakage under various hydrodynamic and biogeochemical conditions. This study introduces a mechanistic and diagnostic framework that combines a two-class population balance equation (TCPBE) model with Bayesian calibration to simulate flocculation?transport behavior in both laboratory- (time-dependent batch) and field-scale (one-dimensional vertical) systems. Laboratory experiments with biopolymer?clay and microalgae?clay mixtures and field observations from an estuarine turbidity maximum zone are used to derive a comprehensive data set for model validation. Bayesian inference enables the estimation of uncertain model parameters while characterizing their statistical properties, thus supporting the mechanistic interpretation of flocculation dynamics. By quantifying how ionic strength and microbial physiology regulate flocculation kinetics and elucidating the turbulence-driven coupling between flocculation kinetics and sediment transport over tidal cycles, the framework demonstrates its suitability as a process-based diagnostic tool capable of effectively capturing SPM dynamics under various conditions. This framework has strong potential to advance the understanding of flocculation dynamics and support a range of applications in inland and estuarine sediment-laden water systems, including river, reservoir, esturine and coastal waters.
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RBINS Staff Publications 2026
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Flocculation dynamics of suspended particulate matter under various tidal conditions
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Understanding the flocculation dynamics of suspended particulate matter is essential for a comprehensive understanding of sediment transport in estuarine and coastal ecosystems. Field observations were conducted during both spring and neap tidal cycles at two contrasting sites, the highly turbulent, low-salinity Xuliujing site of the Yangtze River estuary, and the weakly turbulent, high-salinity Belgian coastal station MOW1. The two sites exhibited different flocculation dynamics and floc size distributions (FSDs). At Xuliujing, strong river discharge and pronounced ebb dominance intensified turbulent shear, making the fragmentation of flocs the governing process. This resulted in multimodal FSDs with high proportions of microflocs (∼13 μm) and macroflocs (∼55 μm). In contrast, at MOW1, high salinity and relatively weak, symmetric tidal currents favored salt-enhanced aggregation, resulting in larger, more stable flocs and more uniform FSDs. These contrasts indicate that in freshwater environments, turbulence controls both aggregation and breakup, whereas in saline waters, salinity governs aggregation and turbulence primarily limits the maximum size of flocs. Furthermore, a one-dimensional vertical hydrodynamic model coupled with a population balance flocculation model demonstrated satisfactory accuracy in simulating current velocities, suspended particulate matter concentrations, and FSDs at both sites, showing its capability to capture flocculation dynamics under different environmental conditions.
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RBINS Staff Publications 2026
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Local and landscape effects on ant functional and taxonomic compositions across green spaces of a tropical metropolis
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Urbanization is one of the main processes driving environmental transformation, altering the structure and functioning of biological communities across multiple spatial scales. In this study, we evaluated the effects of local and landscape variables on the taxonomic and functional composition of ants in different types of urban green spaces in the city of Salvador, Brazil. A total of 62 sampling points were surveyed across forest fragments, squares, streets medians, and vacant lots, using specific methods for both ground-dwelling and arboreal strata. We recorded 93 ant species distributed among 20 functional groups. Our results indicated that, at the local scale, leaf litter depth was the primary explanatory factor for both taxonomic and functional richness, as well as for functional composition. At the landscape scale, human population density and vegetation cover surrounding the sampling points influenced the distribution of species and functional groups, revealing contrasting patterns between specialist and generalist species. While arboreal, hypogeic, and fungivorous ants were more dependent on structurally complex and conserved habitats, epigeic, omnivorous, and some predatory species were favored in more simplified and heterogeneous environments. These findings highlight that biodiversity conservation in urban areas depends on integrated strategies across multiple scales, encompassing management practices that ensure local structural complexity alongside planning that promotes habitat heterogeneity at the landscape level. Overall, the study demonstrates that the arrangement and quality of urban green spaces play a central role in maintaining both taxonomic and functional diversity of ant communities in tropical cities.
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The BiogeochemicAl Model for Hypoxic and Benthic Influenced areas: BAMHBI v1.0
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This paper describes the ocean BiogeochemicAl Model for Hypoxic and Benthic Influenced areas (BAMHBI). BAMHBI is a moderate complexity marine biogeochemical model that describes the cycling of carbon, nitrogen, phosphorus, silicon and oxygen through the marine foodweb. It involves 22 state variables, extends from bacteria up to mesozooplankton and includes three phytoplankton functional types (PFTs), two zooplankton size-classes, a microbial loop with several classes of detritic materials. Five optional modules are available allowing to extend the model with the explicit modelling of Chlorophyll a (Chl a) in each PFT, benthic degradation, gelatinous dynamics, particles aggregation and the carbonate system. BAMHBI describes the degradation of organic matter according to oxygenation conditions using an approach similar to that used in the sediment to simulate early diagenesis. The model is particularly appropriate for modelling low oxygen environments and the generation of sulfidic waters. An optional benthic module solves the degradation of sedimentary organic matter and the benthic-pelagic fluxes of solutes using an efficient formulation based on meta-modelling. This paper describes in details model formulations, implementation and coupling with the physics. BAMHBI's code is written in Fortran and can be coupled with many hydrodynamical models. Two case studies of application of BAMHBI in the Black Sea are described. One describes the application of BAMHBI to simulate the biogeochemical dynamics of the northwestern shelf during the eutrophication period. In particular, the ability of BAMHBI to simulate the oxygen dynamics at seasonal and interannual scales is assessed with a focus on the simulation of bottom hypoxia. We highlight the results of the benthic modelling module and its ability to represent benthic-pelagic fluxes. The second case study compares the BAMHBI simulated Chl a, oxygen and nitrate dynamics in the deep sea with respect to biogeochemical Argo.
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RBINS Staff Publications 2026
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Amplified warming and marine heatwaves in the North Sea under a warming climate and their impacts
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The northeast Atlantic and adjacent regions, such as the North Sea, are among the fastest-warming areas in the world. However, the role of climate change and internal variability in marine heatwaves (MHWs) in this region remains poorly understood. This study aims to quantify the relevant changes in sea surface temperature (SST) and MHWs in the North Sea, as well as to identify the leading patterns of interannual MHW variability over more than 4 decades (1982–2024). Our results indicated a new regime shift in the annual mean SST in the North Sea since 2013. Therefore, we examined the relationships between MHW trends and long-term sea surface warming trends to quantify the role of climate change in the intensification of MHWs. We found that the increase in MHWs is related to the significant decadal change in SST over the North Sea and we have revealed that large-scale climate modes, such as the Atlantic Multidecadal Oscillation and the East Atlantic Pattern, play a crucial role in this decadal change in SST. In particular, the SST trend has doubled in the post-2013 period (0.8 °C per decade), compared with the pre-2013 period (0.4 °C per decade), leading to longer and more frequent MHWs. The SST, MHW frequency, and MHW days increased significantly by 0.38 °C per decade, 1.04 events per decade, and 17.27 d per decade, respectively, over the entire study period. After removing the long-term sea surface warming trend before MHW detection, all MHW features exhibited insignificant trends, indicating that the long-term SST trend is the primary driver of the observed long-term MHW trend in the North Sea region, thereby confirming the crucial role of mean SST changes in MHWs in this region. Furthermore, we found that 80 % of the observed trend in MHW frequency is attributed to long-term warming, while the rest is attributed to internal variability. The SST record in May 2024, manifest by the longest (27 d) and most intense (2.2 °C) MHW event, is attributed to an anomalous anticyclonic atmospheric circulation over the Baltic Sea and southern Norway, which enhanced solar radiation over the North Sea. Finally, we also investigated how the chlorophyll a concentration responded to the MHW, revealing a decrease in the deep and cold-water regions of the northern North Sea and an increase in the shallow and warm-water areas of the southern North Sea.
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RBINS Staff Publications 2025
