In Press Oceanologia, uncorrected, in press Polish Academy of Sciences Institute of Oceanology Open access article under the CC BY license https://doi.org/10.5697/... Glacial bay as a local hot spot for retention and accumulation of heavy metals transported with glacier meltwater (Hornsund, Svalbard)

The main objective of the study was to investigate seasonal sediment dynarnics on the Laptev Sea shelf.The Laptev Sea comprises one of the largest Siberian shelf areas and is characterized by seasonal ice coverage and thus, by a strong seasonality in sediment input.The pathways and the final fate of the sediments derived from the Siberian hinterland are central questions for understanding the complex land-shelf-ocean interactions and their seasonal variations.In order to characterize seasonal variations in suspended particulate matter (SPM) dynamics on the eastem Laptev Sea shelf, one-year Acoustic Doppler Current Profiler (ADCP) records and complementary optical backscatter profiles from the ice-free period were analyzed.

Spatiotemporal changes in the concentration and composition of suspended particulate matter in front of Hansbreen, a tidewater glacier in Svalbard

Trace metals, arsenic and lead isotopes in dissolved and particulate phases of North Australian coastal and estuarine seawater

Dissolved CO2 and buried organic matter budgets have been studied in shelf seas to identify carbon fractions that are exported to the ocean interior or preserved in the sediment. However, the fate of suspended particulate organic matter remains less understood, particularly because its lability is difficult to identify. Analysis of the different fractions of particulate organic matter in the North Sea could contribute to understanding its fate. The particulate organic carbon (POC) concentration follows coastal-offshore gradients that can be predicted with the suspended particulate matter (SPM) concentration. The POC:SPM ratio indeed features a typical exponential decrease with the SPM concentration. While that ratio is higher offshore where SPM concentrations are minimum, it reaches low asymptotic values at the coast where SPM concentrations are high. Such a relationship is actually found in many different systems (coastal zones, estuaries) and at different latitudes. A semi-empirical model has been proposed to fit the observed data of that relationship in the southern North Sea (German Bight: Schartau et al., 2019; Belgian zone: Fettweis et al., 2022). Based on the model assumptions, it is possible to separate two fractions of POC: the fresh fraction, that is assumed to accumulate during the bloom and to be degraded within the season, and a more refractory POC fraction. More detailed calculations allow this latter fraction to be divided into a slow POC, which includes the refractory detritus, and a mineral POC, that is the POC adsorbed on the surfaces of clay minerals. We assume that suspended mineral particles in the North Sea provide a total surface area saturated with adsorbed organic matter, also considering an underlying dynamic equilibrium between adsorption and desorption of organic matter. We then calculate the SPM budget in the North Sea from satellite remote sensing and vertical concentration profiles obtained from in situ observations. On this basis, we can use the semi-empirical model to establish a budget of the fresh, refractory detrital and mineral fractions of POC on the shelf.

The concentrations of trace metals (Cu, Zn, Mn, Ni, and Fe) from suspended particulate matter (SPM) and biota in Izmir Bay (Eastern Aegean Sea) were studied in order to evaluate the environmental impact of the anthropogenic metals before building of Wastewater Treatment Plant. SPM samples were collected in wet and dry periods from Izmir Bay. Metal concentrations in SPM (Cu, 0.36-2.19; Mn, 0.07-11.3; Ni, 0.43-7.81; Zn, 7.33-269; Fe, 1.00-266 μg dm(-3)) were comparable to those reported for other moderately polluted bays. Maximum metal concentrations in SPM were observed during summer season. SPM metal concentrations displayed a clear spatial trend with values increasing with proximity to urban centers. Cu and Zn concentrations in SPM were especially high in the inner bay. SPM were found to be contaminated by Zn. The vertical profile of Mn, Zn, and Ni concentrations in SPM had a maximal value at the upper layer and decreased to minimal value at the bottom layer of the inner bay in summer, in contrast to the observed pattern of Fe and Cu. Maximum Cu concentrations were obtained in Penaeus kerathurus. Also, maximum Zn and Fe concentrations were found in Mytilus galloprovincialis. Relatively high Cu levels were found in Sardina pilcardus and Mullus barbatus than other fish species. Besides, Cu levels were lower in Diplodus annularis and Merluccius merluccius. Finally, metal levels in biota tissues were lower than the limits of European Dietary Standards and Guidelines.

Abstract. Sediment transport dynamics were studied during ice-free conditions under different atmospheric circulation regimes on the Laptev Sea shelf (Siberian Arctic). To study the interannual variability of suspended particulate matter (SPM) dynamics and their coupling with the variability in surface river water distribution on the Laptev Sea shelf, detailed oceanographic, optical (turbidity and Ocean Color satellite data), and hydrochemical (nutrients, SPM, stable oxygen isotopes) process studies were carried out continuously during the summers of 2007 and 2008. Thus, for the first time SPM and nutrient variations on the Laptev Sea shelf under different atmospheric forcing and the implications for the turbidity and transparency of the water column can be presented. The data indicate a clear link between different surface distributions of riverine waters and the SPM transport dynamics within the entire water column. The summer of 2007 was dominated by shoreward winds and an eastward transport of riverine surface waters. The surface SPM concentration on the southeastern inner shelf was elevated, which led to decreased transmissivity and increased light absorption. Surface SPM concentrations in the central and northern Laptev Sea were comparatively low. However, the SPM transport and concentration within the bottom nepheloid layer increased considerably on the entire eastern shelf. The summer of 2008 was dominated by offshore winds and northward transport of the river plume. The surface SPM transport was enhanced and extended onto the mid-shelf, whereas the bottom SPM transport and concentration was diminished. This study suggests that the SPM concentration and transport, in both the surface and bottom nepheloid layers, are associated with the distribution of riverine surface waters which are linked to the atmospheric circulation patterns over the Laptev Sea and the adjacent Arctic Ocean during the open water season. A continuing trend toward shoreward winds, weaker stratification and higher SPM concentration throughout the water column might have severe consequences for the ecosystem on the Laptev Sea shelf.

Seasonal and interannual variations of suspended particulate matter in a West-African lagoon (Nokoué lagoon, Benin): Impact of rivers and wind

The accurate measurement of suspended particulate matter (SPM) concentrations in coastal waters is of crucial importance for ecosystem studies, sediment transport monitoring, and assessment of anthropogenic impacts in the coastal ocean. Ocean color remote sensing is an efficient tool to monitor SPM spatio-temporal variability in coastal waters. However, near-shore satellite images are complex to correct for atmospheric effects due to the proximity of land and to the high level of reflectance caused by high SPM concentrations in the visible and near-infrared spectral regions. The water reflectance signal (ρw) tends to saturate at short visible wavelengths when the SPM concentration increases. Using a comprehensive dataset of high-resolution satellite imagery and in situ SPM and water reflectance data, this study presents (i) an assessment of existing atmospheric correction (AC) algorithms developed for turbid coastal waters; and (ii) a switching method that automatically selects the most sensitive SPM vs. ρw relationship, to avoid saturation effects when computing the SPM concentration. The approach is applied to satellite data acquired by three medium-high spatial resolution sensors (Landsat-8/Operational Land Imager, National Polar-Orbiting Partnership/Visible Infrared Imaging Radiometer Suite and Aqua/Moderate Resolution Imaging Spectrometer) to map the SPM concentration in some of the most turbid areas of the European coastal ocean, namely the Gironde and Loire estuaries as well as Bourgneuf Bay on the French Atlantic coast. For all three sensors, AC methods based on the use of short-wave infrared (SWIR) spectral bands were tested, and the consistency of the retrieved water reflectance was examined along transects from low- to high-turbidity waters. For OLI data, we also compared a SWIR-based AC (ACOLITE) with a method based on multi-temporal analyses of atmospheric constituents (MACCS). For the selected scenes, the ACOLITE-MACCS difference was lower than 7%. Despite some inaccuracies in ρw retrieval, we demonstrate that the SPM concentration can be reliably estimated using OLI, MODIS and VIIRS, regardless of their differences in spatial and spectral resolutions. Match-ups between the OLI-derived SPM concentration and autonomous field measurements from the Loire and Gironde estuaries’ monitoring networks provided satisfactory results. The multi-sensor approach together with the multi-conditional algorithm presented here can be applied to the latest generation of ocean color sensors (namely Sentinel2/MSI and Sentinel3/OLCI) to study SPM dynamics in the coastal ocean at higher spatial and temporal resolutions.

Seasonal variability of suspended particulate matter observed from SeaWiFS images near the Belgian coast

Derivation of sediment resuspension rates from acoustic backscatter time-series in tidal waters

Particulate trace metal (Cu, Cr, Ni, Pb and Zn) and major element (Fe, Mn and Al) concentrations have been determined following intensive sampling over two consecutive spring tidal cycles in the 'turbidity maximum zone' (TMZ) of the Port Jackson estuary, Australia. Salinity, temperature, pH, dissolved oxygen, suspended particulate matter (SPM) and chlorophyll a were also determined. A three-factor analysis of variance was used to test temporal variability in concentrations of particulate trace metals and major elements as a result of tidal oscillation. Estuarine master variables, such as temperature and pH, varied within a narrow range; nevertheless, the tidal signal was clear for surface and bottom waters. In surface water, no variance was detected in SPM concentrations between consecutive tidal cycles or between tidal stages (i.e. flood, ebb and slack water). In bottom water, however, SPM concentrations were significantly higher (P≤0.05) at flood tide than at slack high water and ebb tide. Concentrations of particulate trace metals and major elements in surface water do not display significant variability between tidal cycles or stages. Nevertheless, differences within each tidal stage were significant (P≤0.05) for all elements. In bottom water, only particulate Fe and Al exhibited significant differences (P≤0.05) between tidal cycles, whereas particulate Ni was the only trace element that presented significant differences (P≤0.05) between tidal stages, following the distribution of SPM, with highest concentrations at flood tide. Among the metals studied, significant variation was found at all three temporal scales examined (i.e. from hours to consecutive tidal cycles), although the patterns of variation were different for each metal. The semi-diurnal fluctuation of SPM and particulate trace metal concentrations during spring tides is interpreted as a resuspension–deposition cycle caused by cyclical oscillations of bottom currents. The results are discussed in the context of the implications of tidal cycle influence on the geochemistry and cycling of particulate trace metals in the Port Jackson estuary.

In order to determine the paths of sediment transport to the Laptev Sea and on to the Arctic Ocean we measured 87Sr/86Sr ratios and Sr concentrations of suspended particulate material (SPM) of the Lena, Yana, and Khatanga rivers. The SPM exported to the Laptev Sea by the Lena river is characterized by an average 87Sr/86Sr ratio of 0.7165 ± 0.0005 and a Sr concentration of 200 ± 20 ppm measured at the northernmost stations. The average 87Sr/86Sr ratio (0.7141 ± 0.0002) and Sr concentration (152 ± 5 ppm) of the Yana river SPM can clearly be distinguished from those of the Lena river SPM. Sr isotopie ratios (0.7102 ± 0.0002) and Sr concentrations (181 ± 5 ppm) of the Khatanga river SPM are strongly influenced by volcanic rocks of the Siberian Trap that are very common in the drainage area. Variations in Sr concentrations and isotopie ratios along the Yana and Khatanga rivers result from mixing of material supplied by individual tributaries. The Lena river SPM, on the other hand, exhibits variations which cannot be explained by simple mixing of tributary sediments. Various processes, such as dissolution/absorption and grain-size separation, are considered. The Sr isotopie ratio of each river SPM can be related to isotope data of Laptev Sea surface sediments and sediments incorporated into sea ice. Both indicate that the 87Sr/86Sr ratios can be applied to identify the distribution of riverine material in the Laptev Sea and the Arctic Ocean.

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.

Human impact on suspended particulate matter in the Yellow River Estuary, China: Evidence from remote sensing data fusion using an improved spatiotemporal fusion method

This study aimed to evaluate distribution of selected heavy metals (Cu, Zn, Pb, Cr and Cd) in clams Meretrixlyrata (clam), suspended particulate matter (SPM), water and sediment in the downstream area of Saigon – Dong Nai (SG-DN) River. During March to September 2015, the contamination of those metals at four sampling sites from fresh water to brackish water zone and Meretrix Lyrata clams, which were cultured at many clam farms at Can Thanh beach at Can Gio District, were monitored. The concentrations of metals in clam samples were also determined at a comparative sampling site at Tan Thanh beach (Tien Giang province). Generally, the order of metal concentrations in all environmental components along the SG-DN River was Zn>Cu>Cr>Pb>Cd while the metal concentrations in different environmental components at Can Thanh area were in different orders. According to the results, the increasing tendency of only Cu, Zn and Cd concentrations in SPM and sediment from river upstream to estuary were found. All trace metal concentrations in clam samples were higher than in water and smaller than in sediment and SPM at Can Thanh. Only Cr concentrations in medium and small clam samples had positive significant correlations with those in sediment and SPM (medium size only). In comparison with concentrations of trace metals in water, sediment, SPM and clams at Tan Thanh, those at Can Thanh were higher.