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A trait-based framework to identify North Sea fauna vulnerable to underwater noise
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In the absence of an internationally coordinated management strategy, continued exploitation of the North Sea is expected to exacerbate underwater radiated noise (URN), heightening risks of adverse impacts on marine life. Identifying indicator species and their habitats is a fundamental step in the EU framework for setting a scientifically grounded underwater noise limit value (UNLV). While past research has primarily emphasized marine mammals, there is an increasing effort to highlight that the impacts of URN extend to fishes and invertebrates. To support indicator species selection in the North Sea for URN risk assessment, a trait-based vulnerability scoring system for marine mammals, fishes and invertebrates was developed. Each scoring system evaluates multiple attributes related to a species' capacity to detect and produce sound, as well as the documented impacts from both impulsive and continuous anthropogenic noise, and highlights species of particular concern and socio-ecological significance. Five potential indicator species were identified from each of the three taxonomic groups (marine mammals, fishes and invertebrates) for URN risk assessment. The proposed vulnerability scoring system serves as an adaptive framework, open to iterative refinement as bioacoustics knowledge advances. Although data gaps persist, the establishment of regional UNLV to safeguard vulnerable species should not be delayed. By linking URN exposure with key habitats of identified indicator species, this approach facilitates an ecosystem-based management of URN in the North Sea and provides a transferable framework for other regions.
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RBINS Staff Publications 2026
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Revision of the longirostrine crocodylian Thoracosaurus isorhynchus from the Maastrichtian–Danian of northwestern Europe
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A highly debated topic in eusuchian systematics has been the placement of “thoracosaurs,” an assemblage of Cretaceous–Paleogene longirostrine crocodylians from Europe and North America. The position of “thoracosaurs” varies from one study to the next, from being the sister taxon of the extant Gavialis to being excluded from the crown group Crocodylia entirely. Despite these issues, “thoracosaurs” have been understudied, with many taxa suffering from incomplete or outdated descriptions and dubious taxonomic assignment. Here, we provide a comprehensive study of Thoracosaurus isorhynchus from Maastrichtian–Danian deposits of northwestern Europe. We present and describe new material from the type locality of T. isorhynchus. In addition, we redescribe and figure the lectotype and paralectotypes of the species, as well as the material from the Maastrichtian type area, the Netherlands. Moreover, comparison of T. isorhynchus with the type material of Thoracosaurus “scanicus” of the Danian of southern Sweden indicates that the latter might be a junior synonym of T. isorhynchus, suggesting the survival of this species across the Cretaceous–Paleogene boundary. An array of phylogenetic analyses points to a close relationship between T. isorhynchus and the Cenomanian Portugalosuchus azenhae. This implies an early emergence of “thoracosaurs” and causes extensive ghost lineages within Gavialoidea, highlighting the stratigraphic inconsistency of this group and a need for a thorough revision of other “thoracosaurs.”
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RBINS Staff Publications 2026
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Carboniferous fossils enlighten the systematics and evolution of Hemiptera
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Fossils are witnesses to the evolutionary processes undergone by living lineages. The earliest occurrence of clades provides rich insights into the timing of diversification of lineages and better delimits the groups that compose them. Hemiptera are a remarkable order within the insects due to their high morphological and ecological diversity. However, our understanding of the early evolution of this group remains hampered by the lack of early hemipteran occurrences. In this study we investigate the earliest Carboniferous occurrences of Hemiptera, taking advantage of the redescription of known specimens, and describe three new key hemipteran fossils. We provide thorough taxonomic assessments to describe the earliest occurrences of the Auchenorrhyncha and Sternorrhyncha lineages that constitute major branches in the Hemiptera tree of life. These new occurrences sharpen the delimitations within the classification of Hemiptera and enable better understanding of forewing venation evolution within this hyper-diverse insect order. The following new taxa are described: Protoprosbolomorpha infraorder nov. for Protoprosbole straeleni Laurentiaux, Carbonaturidae fam. nov., Carbonatura oudardi gen. et sp. nov. and Carbopsyllidium minutum gen. et sp. nov.
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RBINS Staff Publications 2026
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Gekko (Gekko) , a new dark-colored tokay gecko from the Thai-Malay border (Squamata, Gekkonidae)
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We describe Gekko dam sp. nov. based on type specimens from a limestone hill in Palian District, Trang Province, southern peninsular Thailand. The new species is also found in Satun Province, southern peninsular Thailand, and in Perlis State, northwestern Peninsular Malaysia. A member of the subgenus Gekko, it differs from all currently recognized Gekko species by the following combination of morphological characters and pattern: maximal known snout-vent length of 149.1 mm, lack of contact between nostrils and rostral, 21–24 interorbital scales between supraciliaries, 72–83 scale rows around midbody, 12–14 dorsal tubercle rows at midbody, 26–28 ventral scale rows at midbody, 22 precloacal pores in males, two postcloacal tubercles on each side of the base of the tail, 14–17 subdigital lamellae on 1st toe and 19–21 on 4th toe, a Y-shaped mark on head, white spots on head, dark grey to black dorsal background with four regular bands of contrasting white spots on dorsum between limb insertions, throat and venter white with orange patches, and a copper iris.
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RBINS Staff Publications 2026
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Quality-control tests for OC4, OC5 and NIR-red satellite chlorophyll-a algorithms applied to coastal waters
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Reliable satellite estimates of chlorophyll-a concentration (Chl-a) are needed in coastal waters for applications such as eutrophication monitoring. However, because of the optical complexity of coastal waters, retrieving accurate Chl-a is still challenging. Many algorithms exist and give quite different performance for different optical conditions but there is no clear definition of the limits of applicability of each algorithm and no clear basis for deciding which algorithm to apply to any given image pixel (reflectance spectrum). Poor quality satellite Chl-a data can easily reach end-users. To remedy this and provide a clear decision on when a specific Chl-a algorithm can be used, we propose simple quality control tests, based on MERIS water leaving reflectance (ρw) bands, to determine on a pixel-by-pixel basis if any of three popular and complementary algorithms can be used. The algorithms being tested are: 1. the OC4 blue-green band ratio algorithm which was designed for open ocean waters; 2. the OC5 algorithm which is based on look-up tables and corrects OC4 overestimation in moderately turbid waters and 3. a near infrared-red (NIR-red) band ratio algorithm designed for eutrophic waters. Using a dataset of 348 in situ Chl-a / MERIS matchups, the conditions for reliable performance of each of the selected algorithms are determined. The approach proposed here looks for the best compromise between the minimization of the relative difference between In situ measurements and satellite estimations and the number of pixels processed. Conditions for a reliable application of OC4 and OC5 depend on ρw412/ρw443 and ρw560, used as proxies of coloured dissolved organic matter and suspended particulate matter (SPM), as compared to ρw560/ρw490, used as a proxy for Chl-a. Conditions for reliable application of the NIR-red band ratio algorithm depend on Chl-a and SPM. These conditions are translated into pixel-based quality control (QC) tests with appropriately chosen thresholds. Results show that by removing data which do not pass QC, the performance of the three selected algorithms is significantly improved. After combining these algorithms, 70\% of the dataset could be processed with a median absolute percent difference of 30.5\%. The QC tests and algorithm merging methodology were then tested on four MERIS images of European waters. The OC5 algorithm was found to be suitable for most pixels, except in very turbid and eutrophic waters along the coasts where the NIR-red band ratio algorithm helps to fill the gap. Finally, a test was performed on an OLCI-S3A image. Although some validations of water reflectance are still needed for the OLCI sensors, results show similar behavior to the MERIS applications which suggests that when applied to OLCI data the present methodology will help to accurately estimate Chl-a in coastal waters for the next decade.
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RBINS Staff Publications 2022
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Monitoring of high biomass Phaeocystis globosa blooms in the Southern North Sea by in situ and future spaceborne hyperspectral radiometry
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Phaeocystis globosa (P. globosa hereafter) is a phytoplankton species which commonly blooms at high biomass in April–May in the Southern North Sea and forms undesirable foam which accumulates on the beaches. Monitoring of this species is required by EU directives. Measurement of phytoplankton species composition has historically been made by pigment or microscopic analysis of water samples, which is spatially sparse and temporally infrequent e.g. weekly/monthly. In-water instruments such as flow cytometers can provide very high frequency data but at high acquisition and maintenance cost. Automated in situ above water radiometry has the potential to provide very high frequency data at single locations but requires very careful design of processing algorithms in turbid waters with high non-algal absorption. Spaceborne radiometry could provide both very good spatial coverage and moderate/high frequency of data, e.g. daily/weekly, but accurate determination of phytoplankton species composition is considerably more difficult in turbid waters than in open ocean waters. Prior studies based on a limited number of shipborne reflectance measurements suggested feasibility of P. globosa detection in turbid waters from hyperspectral radiometry. The availability of a new autonomous above water hyperspectral radiometer system has enabled further refinement and intensive testing of these techniques. From a time-series of 4356 water reflectance spectra measured near Ostend harbour in Belgian coastal waters from 2020/04/01 to 2020/08/18, two existing algorithms for P. globosa detection were successfully applied. Results show a high biomass P. globosa bloom occurring in late-April/early-May as found every year in water sample analyses for Belgian coastal waters. The high temporal resolution of the radiometric data allows to capture the evolution of the bloom at time scales sufficiently short (hourly and daily) compared to growth/decay and tidal processes. The challenges of extending the methods to future spaceborne instruments are also tested by simulating the impact of errors in sensor inter-band calibration, atmospheric correction and radiometric noise. Results show that because of their spectral coherence, atmospheric correction errors impact only slightly P. globosa detection whereas inaccuracy in inter-band calibration and radiometric noise are much more problematic as they affect each spectral band independently. Because radiometric noise should be reduced in the new generation of hyperspectral sensors and can always be reduced by spatial binning, the inter-band relative calibration uncertainty appears to be the main challenge for spaceborne mission design. Indeed, it was demonstrated that inter-band calibration error should be 0.25\% and ideally 0.1\% at top of the atmosphere highlighting the need for particular attention to inter-band calibration in sensor design and post processing treatments including vicarious calibration.
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RBINS Staff Publications 2022
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Suitability of multisensory satellites for long-term chlorophyll assessment in coastal waters: A case study in optically-complex waters of the temperate region
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We investigated the use of multisensory satellite data to determine long-term changes in surface chlorophyll concentrations using a 19-year (1998–2016) time series of chlorophyll data in the Danish Kattegat region of the Baltic Sea. Merged satellite estimates (SeaWiFS-MODIS/Aqua-MERIS-VIIRS) were compared with in situ ship based time series from four monitoring stations situated with increasing distance from land and nutrient sources. In situ and satellite derived estimates showed similar trend in chlorophyll with several fold higher values closer to land. Satellites aligned very well with in situ estimates in the open water stations but showed significant differences in magnitude and inter-annual variability, in particular in shallow coastal waters. Some systematic deviation was observed with satellite underestimating the growing season average for the earlier periods (1998–2002) and overestimating for the later period (2012–2016) compared to in situ estimates. Comparing growing season chlorophyll means over the 19 year period showed increasing magnitude and variability in nearshore and shallower areas, most pronounced for the satellite derived chlorophyll. Satellites overestimated chlorophyll in nearshore areas 2–4 fold, despite excluding shallow nearshore areas with possible benthic interferences from the analyses. This bias needs further validation and requires correction to improve the overall applicability of satellites for long-term monitoring of chlorophyll in the Kattegat region. From analysis of normalized data, we developed a simple correction model, which reduced deviations considerably between methods, underlying the importance of in situ data for application of satellite observations. While significant deviations were observed from in situ data, satellites are clearly advantageous in the much higher temporal and high spatial coverage they provide. Multisensory satellites can, however, not be used currently as a standalone technique for long-term assessment of chlorophyll. They require validation with in situ measurements, which provide essential data for calibration, validation and correction of satellite based estimates. A complementary use of multisensory satellite and in situ measurements therefore remains essential to assess trends in the ecological status of optically complex waters such as the Kattegat region of the Baltic Sea.
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RBINS Staff Publications 2022
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Organic Matter Composition of Biomineral Flocs and Its Influence on Suspended Particulate Matter Dynamics Along a Nearshore to Offshore Transect
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The seasonal variation in concentration of transparent exopolymer particles (TEPs), particulate organic carbon (POC) and particulate organic nitrogen (PON) were investigated together with floc size and the concentration of suspended particulate matter (SPM) along the cross-shore gradient, from the high turbid nearshore toward the low-turbid offshore waters in the Southern Bight of the North Sea. Our data demonstrate that biophysical flocculation cannot be explained by these heterogeneous parameters, but requires a distinction between a more reactive labile (“fresh”) and a less reactive refractory (“mineral-associated”) fraction. Based on all data, we separated the labile and mineral-associated POC, PON, and TEP using a semi-empirical model approach. The model's estimates of fresh and mineral-associated organic matter (OM) show that great parts of the POC, PON, and TEP are associated with suspended minerals, which are present in the water column throughout the year, whereas the occurrence of fresh TEP, POC, and PON is restricted to spring and summer months. In spite of a constantly high abundance of total TEP throughout the entire year, it is its fresh fraction that promotes the formation of larger and faster sinking biomineral flocs, thereby contributing to reducing the SPM concentration in the water column over spring and summer. Our results show that the different components of the SPM, such as minerals, extracellular OM and living organisms, form an integrated dynamic system with direct interactions and feedback controls.
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RBINS Staff Publications 2022
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Comparing life history traits and tolerance to changing environments of two oyster species (Ostrea edulis and Crassostrea gigas) through Dynamic Energy Budget theory
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To predict the response of the European flat oyster (Ostrea edulis) and Pacific cupped oyster (Crassostrea gigas/Magallana gigas) populations to environmental changes, it is key to understand their life history traits. The Dynamic Energy Budget (DEB) theory is a mechanistic framework that enables the quantification of the bioenergetics of development, growth and reproduction from fertilization to death across different life stages. This study estimates the DEB parameters for the European flat oyster, based on a comprehensive dataset, while DEB parameters for the Pacific cupped oyster were extracted from the literature. The DEB parameters for both species were validated using growth rates from laboratory experiments at several constant temperatures and food levels as well as with collected aquaculture data from the Limfjorden, Denmark, and the German Bight. DEB parameters and the Arrhenius temperature parameters were compared to get insight in the life history traits of both species. It is expected that increasing water temperatures due to climate change will be beneficial for both species. Lower assimilation rates and high energy allocation to soma explain O. edulis’ slow growth and low reproductive output. Crassostrea gigas’ high assimilation rate, low investment in soma and extremely low reserve mobility explains the species’ fast growth, high tolerance to starvation and high reproductive output. Hence, the reproductive strategies of both species are considerably different. Flat oysters are especially susceptible to unfavourable environmental conditions during the brooding period, while Pacific oysters’ large investment in reproduction make it well adapted to highly diverse environments. Based on the life history traits, aquaculture and restoration of O. edulis should be executed in environments with suitable and stable conditions.
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RBINS Staff Publications 2022
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Global satellite water classification data products over oceanic, coastal, and inland waters
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Satellites have generated extensive data of remote sensing reflectance spectra (Rrs(λ)) covering diverse water classes or types across global waters. Spectral classification of satellite Rrs(λ) data allows for the distinguishing and grouping of waters with characteristic bio-optical/biogeochemical features that may influence the productivity of a given water body. This study reports new satellite water class products (Level-2 and Level-3) from the Visible Infrared Imaging Radiometer Suite (VIIRS). We developed and implemented a hyperspectral scheme that accounts for the Rrs(λ) spectral shapes and globally resolves oceanic, coastal, and inland waters into 23 water classes. We characterized the light absorption and scattering coefficients, chlorophyll-a concentration, diffuse attenuation coefficient, and suspended particulate matter for individual water classes. It is shown that the water classes are separable by their distinct bio-optical and biogeochemical properties. Furthermore, validation result suggests that the VIIRS water class products are accurate globally. Finally, we examined the spatial and temporal variability of the water classes in case studies for a demonstration of applications. The water class data in open oceans reveal that the subtropical ocean gyres have experienced dramatic expansion over the last decade. In addition, the water class data appear to be a valuable (and qualitative) indicator for water quality in coastal and inland waters with compelling evidence. We stress that this new satellite product is an excellent addition to the aquatic science database, despite the need for continuous improvement toward perfection.
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RBINS Staff Publications 2022
