Combined use of Nassarius reticulatus imposex and statolith age determination for tracking temporal evolution of TBT pollution in the NW Portuguese continental shelf

2011 ◽  
Vol 13 (11) ◽  
pp. 3018 ◽  
Author(s):  
Carlos M. Barroso ◽  
Milene Rato ◽  
Alfredo Veríssimo ◽  
Ana Sousa ◽  
José António Santos ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Temporal Evolution ◽  
Age Determination ◽  
Nassarius Reticulatus ◽  
Combined Use ◽  
Tbt Pollution

ASSESSMENT OF INSHORE/OFFSHORE TRIBUTYLTIN POLLUTION GRADIENTS IN THE NORTHWEST PORTUGAL CONTINENTAL SHELF USING NASSARIUS RETICULATUS AS A BIOINDICATOR

2006 ◽  
Vol 25 (12) ◽  
pp. 3213 ◽  
Author(s):  
Miléne Rato ◽  
Ana Sousa ◽  
Raquel Quintã ◽  
William Langston ◽  
Carlos Barroso
Keyword(s):  
Continental Shelf ◽  
Nassarius Reticulatus

Discovery of imposex in the gastropod Cyclope neritea now invading Galicia (north-west Spain)

2006 ◽  
Vol 86 (5) ◽  
pp. 1171-1173 ◽  
Author(s):  
María Quintela ◽  
Lucía Couceiro ◽  
José Miguel Ruiz ◽  
Rodolfo Barreiro
Keyword(s):  
Invasive Species ◽  
Population Dynamics ◽  
Field Survey ◽  
North West ◽  
Egg Capsules ◽  
Nassarius Reticulatus ◽  
Tbt Pollution

A field survey to re-assess imposex and tributyltin (TBT) bioaccumulation in the gastropod Nassarius reticulatus over Galicia uncovered three populations of the invasive species Cyclope neritea, all showing some advanced imposex. One female was found to carry a mass of aborted egg capsules. The TBT pollution, now decreasing in the area, is the most likely explanation for these reproductive anomalies, and it may bear some relationship to the described population dynamics of C. neritea.

Evaluation of the use of transplanted Nassarius reticulatus (Linnaeus, 1758), in monitoring TBT pollution, within the European Water Framework Directive

2010 ◽  
Vol 10 (4) ◽  
pp. 891-895 ◽  
Author(s):  
J. Germán Rodríguez ◽  
Piero Rouget ◽  
Javier Franco ◽  
Joxe Mikel Garmendia ◽  
Iñigo Muxika ◽  
...  
Keyword(s):  
Water Framework Directive ◽  
European Water Framework Directive ◽  
European Water ◽  
Nassarius Reticulatus ◽  
Tbt Pollution

The Quaternary geology of the Labrador Shelf

1986 ◽  
Vol 23 (8) ◽  
pp. 1190-1213 ◽  
Author(s):  
H. W. Josenhans ◽  
J. Zevenhuizen ◽  
R. A. Klassen
Keyword(s):  
Continental Shelf ◽  
Regional Distribution ◽  
Age Determination ◽  
Late Glacial ◽  
Bottom Currents ◽  
Radiocarbon Age ◽  
Last Glacial ◽  
Multidisciplinary Analysis ◽  
Glaciomarine Sediments ◽  
The Last Glacial

The regional distribution of glacial and postglacial sediments on the Labrador Shelf was mapped by medium- and high-resolution seismics and shows a succession of tills that extend to the continental shelf edge at approximately 600 m. The uppermost of these tills is less laterally extensive and does not occur on the Labrador Shelf bank tops in water depths less than 160 m. We infer that the last glacial episode was less extensive than the preceding ones. Glaciomarine stratified silts and postglacial muds are found overlying the upper till in the deep basins that separate the banks. The upper till, glaciomarine silts, and postglacial muds are interpreted to constitute one complete deglacial cycle. Radiocarbon age determination suggests this deglacial sequence began at approximately 20 000 years BP. On the northernmost Labrador Shelf and Hudson Strait, seismic evidence indicates a late glacial readvance locally deposited a till that overlies the glaciomarine sediments associated with the last glacial advance on the Labrador Shelf. The stratigraphic position of this Hudson Strait till suggests the local readvance occurred at approximately 8000 years BP. The acoustic stratigraphic framework (data) is ground truthed by a regionally extensive piston core and grab sample network. Multidisciplinary analysis of these sediment samples included X-ray, textural, geotechnical, paleontological, lithological, trace-element, and 14C analyses. The results confirm the acoustic interpretations and show that each of the stratigraphic units defined have unique and regionally consistent properties. Geotechnical analyses from the upper till indicate low shear strengths (± 25 kPa) and low to normal consolidation ratios (0.8–2.8), which we interpret to indicate deposition under low basal loading as a result of hydrostatic support on an ice shelf in a marine setting. Provenance studies on the sands and gravels from each of the stratigraphic units of the last deglacial sequence (i.e., till, glaciomarine silts, postglacial muds) indicate that the till is mostly derived from mainland Labrador and transported by an easterly ice flow. Since limestone outcrops are rare to absent on the Labrador mainland and continental shelf, high limestone concentrations (up to 80%) within the glaciomarine sediments that overlie the upper till indicate a northern and distal source for that unit. We interpret an active ice margin overlying the Paleozoic limestone outcrops in Hudson Strait and Ungava Bay as being the dominant source for the glaciomarine silts. The absence of limestone within the postglacial muds that overlie the glaciomarine silts indicates a significant change in provenance, which we attribute to the disappearance of the active ice margin over the limestone terranes. The depositional style and sedimentary structures within the glaciomarine silts indicate low bottom currents and a uniform rain out of ice-rafted (limestone) debris that extends to the southernmost part of the Labrador Shelf. The depositional style of the postglacial muds indicates a significant increase in bottom currents, with deposition restricted to the deep basins. We suggest these increased currents resulted from the disappearance of the Hudson Strait ice barrier, which allowed the Canadian current to develop and combine with the west Greenland current. This combination of currents occurred at approximately 8000 years BP and marks the inception of the Labrador current, which presently traverses the Labrador Shelf.

Multiple dating approaches applied to the recent sediments in the Yangtze River (Changjiang) subaqueous delta

The Holocene ◽  
2018 ◽  
Vol 28 (6) ◽  
pp. 858-866 ◽  
Author(s):  
Feng Wang ◽  
Xiaomei Nian ◽  
Jinlong Wang ◽  
Weiguo Zhang ◽  
Guyu Peng ◽  
...  
Keyword(s):  
Yangtze River ◽  
Accumulation Rate ◽  
Age Determination ◽  
Global Fallout ◽  
The Yangtze River ◽  
Dynamic Nature ◽  
Combined Use ◽  
Clear Peak ◽  
Alternative Techniques ◽  
Recent Sediments

The accumulation rate of recent deposits in a delta environment is critical to the study of delta dynamics and their sustainable management. The most commonly used dating approach for recent (<100 years) deposits is based on radionuclide analyses (e.g. 210Pb, 137Cs and 239 + 240Pu), while alternative techniques, such as microplastics dating, are emerging. In this study, a 180-cm sediment core from the Yangtze River (Changjiang) subaqueous delta was dated using multiple techniques, including 210Pb, 137Cs, 239 + 240Pu geochronology, microplastics content, and optically stimulated luminescence (OSL) dating. The radionuclide profiles show an irregular profile of 210Pb, while 239 + 240Pu exhibit a clear peak of activity at 74 ± 2 cm, which is linked to the maximum global fallout in 1963. Microplastics were not detected below a depth of 90 cm with maximum counts occurring in the top 16 cm. OSL analysis was conducted on the dominant grain size of the quartz (around 4–11 µm) and the ages were ~60 years older than those derived from 210Pb, 137Cs, 239 + 240Pu, and microplastics analyses. We infer that the relatively old quartz OSL ages are most likely caused by residual OSL signals arising from poorly bleached grains at the time of deposition. The profiles of 210Pb, 137Cs and 239 + 240Pu activities, microplastics content, and OSL ages indicate a variable sedimentation rate over the last ~200 years reflecting the dynamic nature of delta deposits. This study shows that both OSL and microplastics particles are promising dating tools for recent young deltaic sediments, and their combined use, alongside radionuclide methods, increases the reliability of age determination.

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