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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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Summary of our present knowledge of the spider communities of the Galápagos archipelago. First analysis of the spider communities of the islands Santa Cruz and Isabela
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RBINS Staff Publications
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Summary of the state of correlation in the Devonian of the Ardennes (Belgium-NE France) resulting from the decisions of the SDS
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RBINS Staff Publications 2016
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Supplementary feeding increases nestling feather corticosterone early in the breeding season in house sparrows
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RBINS Staff Publications 2017
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Supplementary morphological information for Cornufer manus (Kraus & Allison, 2009) and Cornufer vogti (Hediger, 1934), with information on colour in life
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Manus Island is part of the Admiralty Islands, a herpetologically rich but poorly studied area. Seven species of Cornufer (von Tschudi, 1838) are known to occur on the island, five of which have been described. Based on material collected from Manus Island in 2014, we here describe the first female of Cornufer manus and the first male of Cornufer vogti. Additionally, we provide new information on intraspecific variation from a further eight adult males of C. manus, two subadults of C. vogti, as well as the first photographs of both species in life.
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RBINS Staff Publications 2022
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Sur la faune ichthyologique des formations du Panisel et de Den Hoorn
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RBINS Staff Publications
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Sur les otolithes des Sables de Grimmertingen (Oligocène Inférieur de Belgique)
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RBINS Staff Publications
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Surf zone fauna of Ecuadorian sandy beaches: Spatial and temporal patterns
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Sandy beaches and their surf zones are the most common open shoreline habitat; however, surf zone fauna in the tropics is one of the least studied communities in the world. In the current study, we tested the hypothesis that Ecuadorian surf zone hyperbenthos (invertebrates and vertebrates 1–5 mm in length) and epibenthos (fish and macrocrustaceans N 5 mm in length) vary among beaches and seasons. Therefore, the fauna was described and related to environmental variables. In addition, indicator taxa were identified. The hyperbenthos was divided into holo- and mero-hyperbenthos depending on whether taxa were present during their entire life or only early life stages, respectively. Sampleswere collected at eight different beaches during thewet, dry and intermediate or transitional season during the low spring tide, from 1999 to 2000, using a hyperbenthic sledge and epibenthic trawl. A total of 447 hyperbenthic and 30 epibenthic taxawere collected, most of which were crustaceans and fish, respectively (52 and 60% of taxa). The mysid, Metamysidopsis sp.,was the most abundant member of the hyperbenthos (average±SD: 14,425±40,039 ind. 100m−2, present in 92% of samples collected), and the swimming blue crab, Areneus mexicanus, was the most encountered species among the epibenthos (1 ± 1 ind. 100 m−2, 97% of samples collected). All faunal groups varied among beaches, while the holo-hyperbenthos and less strongly the epibenthos varied among seasons. Variability in the three faunas among beaches, distance from the continental slope and the Guayas estuarine system, and beach water physical characteristics were all strongly correlated suggesting adjacent habitats can influence surf zone biological communities and water physical characteristics. Seasonal effects were related to changes inwater physical characteristics among seasons potentially reflecting changes in oceanic currents. These results suggest that, similarly to other beaches around the world, Ecuadorian surf zone fauna is abundant, diverse, and vary among beaches and, for some faunal groups, among seasons, potentially due to the influence of adjacent habitats and seasonal changes in oceanic currents.
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RBINS Staff Publications 2017
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Surface movement above old coal longwalls after mine closure
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Although most subsidence occurs in the months and years after mining by the longwall method, surface movement is still occurring many decades after the mining. The aim of the study is to quantify the long term behavior. Satellite data (radar-interferometry) were analyzed to study an area of about 2km2 during the 18years following the closure of the underground infrastructure and the flooding of the underground workings and rock mass. It was observed that, on average, a residual downward movement took place till 7–12years after the closure, followed by a clear uplift. However, the first signs of an uplift occurred in certain sub-areas 3–4years after the closure. Zones within the area studied were identified with either larger or smaller movements. However, the spatial variation of the surface subsidence or uplift could not be directly explained by the characteristics of mining.
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RBINS Staff Publications 2017
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Surface suspended particulate matter concentration in Taiwan Strait during summer and winter monsoon
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The Taiwan Strait (TS), situated between Taiwan and China, is shallow, relatively turbid, and characterized by strong tidal currents and winter and summer monsoon seasons. The aim of this study was to use images from the Moderate Resolution Imaging Spectroradiometer (MODIS)on board the Aqua satellite to investigate how local sediment sources in addition to the seasonality in wind, oceanographic currents, and waves influence the suspended particulate matter (SPM) dynamics in the TS. In winter, northeast (NE) winds drive the China Coastal Current southward. Cold water with a high SPM concentration is transported southward into the Strait. After the highest SPM concentration reaches its peak in December and January, the winds weaken and the SPM concentration decreases. During summer, winds are less strong and SPM concentration is lower. Although typhoons typically occur in summer, they generate only a weak signal in the surface SPM concentration data from MODIS because of the low number of cloud-free images during these periods. Typhoons result in a short-term increase in the SPM concentration but do not strongly influence the seasonal values in the satellite-derived SPM concentration maps.
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RBINS Staff Publications 2016
