scholarly journals DISTRIBUTION OF DINOCYSTS IN THE SURFACE SEDIMENTS OF SIDI MOUSSA LAGOON : (ATLANTIC COAST-MOROCCO)

2022 ◽  
Vol XLVI-4/W3-2021 ◽  
pp. 65-70
Author(s):  
K. Chaira ◽  
B. Ennaffah ◽  
F. Z. Bouthir ◽  
H. Abdelouahab ◽  
H. Rhinane
Keyword(s):  
Surface Sediments ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Industrial Complex ◽  
Present Survey ◽  
Dinoflagellate Cyst ◽  
Toxic Species ◽  
Sampling Network ◽  
Bloom Formation ◽  
El Jadida

Abstract. The Sidi Moussa lagoon, (32°52′0″ N / 8° 51′05″ W) is located on the Moroccan Atlantic coast between the cities of El Jadida and Safi about 15 km South of the Jorf Lasfar industrial complex, The climate of the lagoon is classified as hot temperate. It is characterised by an oceanic influence. This study of dinoflagellate cyst mapping is the first of its kind from the Sidi Moussa lagoon. the objectives of the present survey were (i) to evaluate to the spatial variation of dinoflagellate cyst assemblages in the sediment along the Sidi Moussa lagoon (ii) to assess the densities of its cysts (iii) to compare the cyst assemblages in this study with that of other sites. The data were collected in a scientific campaign by zodiac carried out from in April 2018 by core following a sampling network of 21 stations distributed randomly in the study area. The surface layer of the sediment cores (3 cm) was sliced and kept at 4° C until analysis. The highest total cyst abundance was 194 cysts. g−1 dry sediment. The Pearson statistical test revealed a positive and significant correlation between cyst abundance and water content, organic matter and of fine sediment. Our study showed the presence of morphotypes of potentially toxic species. The cysts of these species present in the sediment of the Sidi Moussa lagoon could germinate, when environmental conditions become favorable, and in turn could inoculate the water column with the subsequent bloom formation. This study confirms the usefulness of cyst analysis in the assessment of harmful bloom risk in this area important for oyster’s culture.

scholarly journals Effects of Macrofaunal Recolonization on Biogeochemical Processes and Microbiota—A Mesocosm Study

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1599
Author(s):  
Annika Fiskal ◽  
Aixala Gaillard ◽  
Sebastien Giroud ◽  
Dejan Malcic ◽  
Prachi Joshi ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bottom Water ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Lake Basin ◽  
Sediment Properties ◽  
Chironomid Larvae ◽  
Sediment Reworking ◽  
Mesocosm Experiments ◽  
Tubificid Worms

Macroinvertebrates are widespread in lake sediments and alter sedimentary properties through their activity (bioturbation). Understanding the interactions between bioturbation and sediment properties is important given that lakes are important sinks and sources of carbon and nutrients. We studied the biogeochemical impact of macrofauna on surface sediments in 3-month-long mesocosm experiments conducted using sediment cores from a hypoxic, macrofauna-free lake basin. Experimental units consisted of hypoxic controls, oxic treatments, and oxic treatments that were experimentally colonized with chironomid larvae or tubificid worms. Overall, the presence of O2 in bottom water had the strongest geochemical effect and led to oxidation of sediments down to 2 cm depth. Relative to macrofauna-free oxic treatments, chironomid larvae increased sediment pore water concentrations of nitrate and sulfate and lowered porewater concentrations of reduced metals (Fe2+, Mn2+), presumably by burrow ventilation, whereas tubificid worms increased the redox potential, possibly through sediment reworking. Microbial communities were very similar across oxic treatments; however, the fractions of α-, β-, and γ-Proteobacteria and Sphingobacteriia increased, whereas those of Actinobacteria, Planctomycetes, and Omnitrophica decreased compared to hypoxic controls. Sediment microbial communities were, moreover, distinct from those of macrofaunal tubes or feces. We suggest that, under the conditions studied, bottom water oxygenation has a stronger biogeochemical impact on lacustrine surface sediments than macrofaunal bioturbation.

scholarly journals Linking patterns of freshwater discharge and sources of organic matter within the Río de la Plata estuary and adjacent marshes

2017 ◽  
Vol 68 (9) ◽  
pp. 1704 ◽  
Author(s):  
Leandro Bergamino ◽  
Mark Schuerch ◽  
Adriana Tudurí ◽  
Silvina Carretero ◽  
Felipe García-Rodríguez
Keyword(s):  
Organic Matter ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Freshwater Discharge ◽  
C3 Plants ◽  
Estuarine System ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
La Plata ◽  
Matter Transport

We investigated carbon isotopic ratios (δ13C) v. carbon to nitrogen (C : N) ratios for surface sediments throughout a large estuarine system (Río de la Plata, RdlP), combined with sediment cores from adjacent marshes to infer main carbon sources. We also evaluated the influence of the El Niño–Southern Oscillation (ENSO) and associated high freshwater-discharge events on the organic-matter transport within the estuary. The isotopic pattern in surface sediments of the RdlP showed the upper reaches to be influenced by riverine particulate matter (δ13C range: –24 to –26‰). Similarly, in the sediment cores from marshes of the upper reaches, δ13C values decreased from –24‰ in ancient sediments to –28‰ in recent sediments, reflecting an increased contribution of organic matter from land, including C3 plants and freshwater phytoplankton, during the past 50 years. However, the lower reaches represent a depositional environment of marine algae (δ13C range: –21 to –23‰), with no influence of detritus from adjacent marshes, indicating minor erosion of the marshes in the lower reaches operating as carbon-sink habitats. Our isotopic analysis showed that the transport and deposition of terrigenous organic matter within the RdlP and adjacent marsh habitat appear to be both temporally and spatially linked to hydrology patterns.

Dinoflagellate cyst distribution in surface sediments along the south-western Mexican coast (14.76° N to 24.75°N)

2010 ◽  
Vol 76 (3-4) ◽  
pp. 104-123 ◽  
Author(s):  
Audrey Limoges ◽  
Jean-François Kielt ◽  
Taoufik Radi ◽  
Ana Carolina Ruíz-Fernandez ◽  
Anne de Vernal
Keyword(s):  
Surface Sediments ◽  
The South ◽  
Dinoflagellate Cyst

scholarly journals A new device to mount portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) for semi-continuous analyses of split (sediment) cores and solid samples

2017 ◽  
Vol 6 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Philipp Hoelzmann ◽  
Torsten Klein ◽  
Frank Kutz ◽  
Brigitta Schütt
Keyword(s):  
Spatial Resolution ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Ccd Camera ◽  
Energy Dispersive ◽  
Solid Samples ◽  
Industrial Property ◽  
X Ray ◽  
New Device ◽  
Sample Chamber

Abstract. Portable energy-dispersive X-ray fluorescence spectrometers (p-ED-XRF) have become increasingly popular in sedimentary laboratories to quantify the chemical composition of a range of materials such as sediments, soils, solid samples, and artefacts. Here, we introduce a low-cost, clearly arranged unit that functions as a sample chamber (German industrial property rights no. 20 2014 106 048.0) for p-ED-XRF devices to facilitate economic, non-destructive, fast, and semi-continuous analysis of (sediment) cores or other solid samples. The spatial resolution of the measurements is limited to the specifications of the applied p-ED-XRF device – in our case a Thermo Scientific Niton XL3t p-ED-XRF spectrometer with a maximum spatial resolution of 0.3 cm and equipped with a charge-coupled device (CCD) camera to document the measurement spot. We demonstrate the strength of combining p-ED-XRF analyses with this new sample chamber to identify Holocene facies changes (e.g. marine vs. terrestrial sedimentary facies) using a sediment core from an estuarine environment in the context of a geoarchaeological investigation at the Atlantic coast of southern Spain.

scholarly journals An Invasive Mussel (Arcuatula senhousia, Benson 1842) Interacts with Resident Biota in Controlling Benthic Ecosystem Functioning

2020 ◽  
Vol 8 (12) ◽  
pp. 963
Author(s):  
Guillaume Bernard ◽  
Laura Kauppi ◽  
Nicolas Lavesque ◽  
Aurélie Ciutat ◽  
Antoine Grémare ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Ecosystem Functioning ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Environmental Drivers ◽  
Zostera Noltei ◽  
Invasion Stage ◽  
Solute Fluxes ◽  
Excretion Rates ◽  
Invasive Mussel

The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment–water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic–pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.

Distribution of common modern dinoflagellate cyst taxa in surface sediments of the Northern Hemisphere in relation to environmental parameters: The new n=1968 database

2020 ◽  
Vol 159 ◽  
pp. 101796 ◽  
Author(s):  
Anne de Vernal ◽  
Taoufik Radi ◽  
Sebastien Zaragosi ◽  
Nicolas Van Nieuwenhove ◽  
André Rochon ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Surface Sediments ◽  
Environmental Parameters ◽  
Dinoflagellate Cyst

scholarly journals Bottom structure of selected basins in The Port of Gdynia

2016 ◽  
Vol 32 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Janusz Dworniczak ◽  
Radosław Wróblewski ◽  
Stanisław Rudowski ◽  
Patryk Sitkiewicz ◽  
Malwina Bieszk
Keyword(s):  
Land Surface ◽  
Surface Sediments ◽  
Sediment Cores ◽  
Lacustrine Sediments ◽  
Seismic Profiles ◽  
Geological Cross Section ◽  
Geological Map ◽  
The Rich ◽  
Bottom Depth ◽  
Bathymetric Map

Bottom structure of the basins in the Port of Gdynia, Poland, was analysed based on the archival materials of the Department of Operational Oceanography of Marine Institute in Gdańsk, particularly seismic profiles and macroscopic descriptions of sediment cores. Seismic profiling and core collection were performed in selected basins and within the fairway. The rich source material was used to draw a detailed bathymetric map of the bottom of the basins, a map of surface sediments, and a synthetic geological cross-section. A considerable variation in bottom depth within the analysed basins was observed. Bedrock sediments comprised Miocene sands and silts covered with glacial and fluvioglacial sediments, which reach the surface of the water, especially in the central part of the fairway. Within the eastern part of the fairway, fluvioglacial sediments are covered with marine sediments related to the Littorina transgression. Within the inner port and in the outport, a series of glacial and fluvioglacial sediments are covered with a thick (about 10 m) series of glaciolacustrine and lacustrine sediments, which in turn is covered with fluvial and deltaic sediments. The surface of the bottom is composed of contemporary, anthropogenically modified sediments. The map of surface sediments of the bottom corresponds to the geological map on the horizon of about 10 meters beneath land surface.

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