scholarly journals Core descriptions, core photographs, physical property logs and surface textural data of sediment cores recovered from the continental shelf of the Monterey Bay National Marine Sanctuary during the research cruises M-1-95-MB, P-2-95-MB, and P-1-97-MB

2001 ◽  
Author(s):  
Kevin M. Orzech ◽  
Wendy E. Dahl ◽  
Brian D. Edwards
Keyword(s):  
Continental Shelf ◽  
Sediment Cores ◽  
Physical Property ◽  
Monterey Bay ◽  
Textural Data ◽  
Core Descriptions

scholarly journals Suspended particulate layers and internal waves over the southern Monterey Bay continental shelf: An important control on shelf mud belts?

2014 ◽  
Vol 119 (1) ◽  
pp. 428-444 ◽  
Author(s):  
Olivia M. Cheriton ◽  
Erika E. McPhee-Shaw ◽  
William J. Shaw ◽  
Timothy P. Stanton ◽  
James G. Bellingham ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Internal Waves ◽  
Monterey Bay ◽  
Suspended Particulate

Domoic acid in benthic flatfish on the continental shelf of Monterey Bay, California, USA

2007 ◽  
Vol 151 (6) ◽  
pp. 2053-2062 ◽  
Author(s):  
Veronica L. Vigilant ◽  
Mary W. Silver
Keyword(s):  
Continental Shelf ◽  
Domoic Acid ◽  
Monterey Bay

scholarly journals Records of plutonium isotopes in marine sediments from the southern Gulf of Mexico

2021 ◽  
Author(s):  
Jose A. Corcho Alvarado ◽  
Misael Diaz-Asenciuo ◽  
Stefan Röllin ◽  
Juan Carlos Herguera
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Water Column ◽  
Deep Sea ◽  
Sediment Cores ◽  
Global Fallout ◽  
Tropical Region ◽  
Deep Sea Sediments ◽  
Pu Isotopes ◽  
Upper Slope

Abstract Here we report on new data on plutonium (Pu) isotopes to elucidate activity concentrations, inventories, sources and their transport from the ocean surface to the sea floor from a collection of deep-sea sediment cores (depths ranging from 257 to 3739 m) in the Gulf of Mexico (GoM). Sediment cores collected from the continental shelf and upper slope region of the GoM consistently showed 240Pu/239Pu ratios of 0.15 to 0.26 and Pu-inventories ranging from 15 to 35 Bq m− 2. Inventories and ratios are consistent with global fallout Pu for this tropical region. In the continental shelf and upper slope regions, higher particle concentrations close to the margins favor significant scavenging and removal of Pu from the water column; in contrast with the deep-sea cores that show low 240Pu/239Pu ratios (0.07–0.13) and a much lower Pu inventory (< 7 Bq m-2) implying a small fraction of the expected global fallout inventory has reached into the lower slopes and abyssal plain of the GoM. Low values and a progressive decrease of 240Pu/239Pu ratios and Pu inventories with increasing water depth have been previously reported for the GoM. The low Pu ratios indicate that Nevada tests fallout was an important source of Pu to deep-sea sediments, and that this source was likely more efficiently removed from the water column than global fallout Pu. Analysis of Pu isotopes in two sediment traps from the upper slope regions show 240Pu/239Pu ratios comparable to the ones observed in the global fallout. These results indicate that global fallout Pu is currently the main source of Pu in water column particles. Therefore, a significant fraction of global fallout Pu must still be present; either in a dissolved phase, or as biologically recycled material in the water column, or scavenged on the shelf and shelf break. Our results bring to light important questions on the application of Pu isotopes to establish sediment chronologies, since these radionuclides are shown to be tracers of bioturbation rather than accumulation processes in deep-sea sediments of the GoM, similar to previously reported results from excess 210Pb.

scholarly journals Long-term seafloor morphological changes generated by bottom trawling on the northern Catalan continental shelf (NW Mediterranean)

2021 ◽  
Author(s):  
Ruth Durán ◽  
Pere Puig ◽  
Araceli Muñoz ◽  
Claudio Lo Iacono ◽  
Jorge Guillén ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Sediment Cores ◽  
Seafloor Morphology ◽  
Bottom Trawling ◽  
Side Scan Sonar ◽  
Nw Mediterranean ◽  
High Backscatter ◽  
Sonar Images ◽  
Spanish Research

&lt;p&gt;The north-western Mediterranean continental margin is one of the few regions in the world where bottom trawling has been continuously practised since several decades. Among the existing trawling techniques, the one practised on this region is the &quot;otter trawling&quot;, which has a strong impact on the seafloor morphology via scraping and ploughing, especially on muddy substrates. High-resolution multibeam bathymetry and backscatter data, side scan sonar images, sediment cores and satellite based Vessel Monitoring System (VMS) data have been integrated to investigate the impact of bottom trawling on the seafloor morphology of the northern Catalan continental shelf (NW Mediterranean). Satellite-based navigation tracks from bottom trawlers operating in the study area during 6 years (2006-2011) reveal the spatial distribution of fishing grounds and the occurrence of an intense trawling effort around the 50-60 m isobaths, since trawling is banned at shallow depths. Backscatter imagery shows a narrow (120-250 m wide) and discontinuous high backscatter facies along this depth range, extending parallel to the coastline for more than 40 km from Portbou to l&amp;#8217;Estartit. In the bathymetric data, this high backscatter region also coincides with an abrupt change in the mean seafloor gradient (from 0.8&amp;#176; in the inner shelf to 0.4&amp;#176; in the middle shelf), or locally with a narrow (50-150 m wide) slightly depressed (0.2-0.6 m deep) channeled morphology. Side-scan sonar images display high density of trawl marks generated by fishing gears in this area. Further offshore, scattered narrower trawl hauls are also observed on the middle shelf (60-90 m deep), where they can be traced across several thousands of meters. Sediment cores retrieved from the area of high backscatter and largest trawling intensity display sediment coarsening in the upper layers (0-4 cm) caused by winnowing of finer fractions. These findings demonstrate that chronic stirring, mixing and erosion of surface sediments induced by recurrent trawling persisting over the same fishing grounds can cause long-term morphological and sedimentary changes on the continental shelf seafloor.&lt;/p&gt;&lt;p&gt;This study has received funding from the ABIDES (Assessment of Bottom-trawling Impacts in the Deep-sea Sediments) Spanish Research Project (CTM2015-65142-R) and the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No. 867471. Additional funds were provided by the Generalitat de Catalunya Generalitat de Catalunya (2017 SGR-663 and -1588) and by the Spanish Research Project ABRIC (RTI2018-096434-B-I00). This work is contributing to the ICM&amp;#8217;s &amp;#8216;Center of Excellence&amp;#8217; Severo Ochoa (CEX2019-000928-S). The authors wish to thank the Secretar&amp;#237;a General de Pesca and Tragsa for the 2004 Espace Project dataset.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document