scholarly journals The REBENT monitoring network, a spatially integrated, acoustic approach to surveying nearshore macrobenthic habitats: application to the Bay of Concarneau (South Brittany, France)

2006 ◽  
Vol 63 (9) ◽  
pp. 1604-1615 ◽  
Author(s):  
Axel Ehrhold ◽  
Dominique Hamon ◽  
Brigitte Guillaumont
Keyword(s):  
Small Area ◽  
Biological Diversity ◽  
Monitoring Network ◽  
Biological Characteristics ◽  
Survey Area ◽  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Astronomical Tide ◽  
Ground Truthing ◽  
Acoustic Facies

Abstract A 200-km2 area in the Bay of Concarneau on the South Brittany coast was surveyed acoustically using different sidescan sonars (a 100-kHz EdgeTech DF1000, and a 240-kHz Reson SeaBat 8101). The area corresponds to a sector of the REBENT network. It was selected for its physical and biological characteristics, reflecting the sedimentary heterogeneity and biological diversity of Brittany's coastal seafloors. The work presented here illustrates the methodology for mapping subtidal seabed habitats in the context of the network. Backscatter mosaics were produced covering 100% of the survey area. Extensive ground-truthing was carried out involving 93 Shipek grab samples and 25 drop-down video profiles. From interpretation of the acoustic facies, 40 biological soft-bottom stations were sampled using a Hamon grab to characterize macrobenthic communities (>2 mm). The results indicated considerable variation in backscatter responses in relation to high densities of macrobenthic species (Lithothamnion, Asterias, Haploops, Maldane, Ophiocomina), and a wide variety of substratum types present within a relatively small area. Dense biocenoses of maerl were accurately surveyed from 20-m to <5-m depth (Lower Astronomical Tide; LAT). Boundaries of Haploops communities are associated with dense small pockmarks in the centre of the bay. The relationships between sediment sometimes colonized by macrobenthic species and backscatter responses are discussed.

Minimal sampling requirements for a precise assessment of soft-bottom macrobenthic communities, using AMBI

2007 ◽  
Vol 349 (2) ◽  
pp. 323-333 ◽  
Author(s):  
Iñigo Muxika ◽  
Leire Ibaibarriaga ◽  
José Ignacio Sáiz ◽  
Ángel Borja
Keyword(s):  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Precise Assessment

Acoustic interpretation of Quaternary sedimentation and erosion on the channelled upper Laurentian Fan, Atlantic margin of Canada

1982 ◽  
Vol 19 (10) ◽  
pp. 1974-1984 ◽  
Author(s):  
David J. W. Piper ◽  
William R. Normark
Keyword(s):  
Single Channel ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Survey Area ◽  
Overbank Sediments ◽  
Abandoned Channel ◽  
Acoustic Facies ◽  
Seismic Reflection Profiles ◽  
Atlantic Margin ◽  
To Receive

About 1000 km of single-channel seismic-reflection profiles from a 50 km × 100 km area on the upper Laurentian Fan shows no evidence of the large slumps interpreted by previous workers in this area. Our detailed profile grid indicates that slump-like masses are commonly in depositional continuity with definite autochthonous sediments, and surfaces previously interpreted as slide planes are either facies changes or the result of valley-wall erosion. Only a few small slump blocks of relatively consolidated sediment are found on the uppermost fan. Acoustic-facies distribution shows a single Early (?) Pleistocene fan valley crossing the northeast part of the survey area with thick overbank sediments to the southwest. In the middle (?) Pleistocene this valley became incised. Its upper reaches then ceased to receive sediment, and a new valley was cut extending southward from the upper slope and intercepting the lower reaches of the old fan valley. This channel diversion was probably related either to the glacial excavation of the Laurentian Channel or to a major slump scar that formed east of the survey area. Most of the old abandoned channel was plugged by overbank deposits from the new master channel. Two other valleys farther west also developed at this time or somewhat earlier. In Late Pleistocene time, all three valleys were incised and more than 1 km of sedimentary material was stripped from much of the uppermost part of the fan, probably as a result of headward erosion of submarine canyons and general thalweg lowering.

Efficiency of sampling gears (Quadrate and Core) and Taxonomic Resolution on the Soft Bottom Intertidal Macrobenthic community of Port Blair coast

2021 ◽  
Vol 25 (11) ◽  
pp. 93-103
Author(s):  
Nosad Sahu ◽  
Ganesh Thiruchitrambalam ◽  
Raj Kiran Lakra
Keyword(s):  
Correlation Coefficient ◽  
Similarity Index ◽  
Rank Correlation ◽  
Work Capacity ◽  
Information Loss ◽  
Taxonomic Resolution ◽  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Taxonomic Level ◽  
Family Level

Ecological studies of a region cannot proceed forward without the evaluation of species diversity. With the ever-increasing demand for studies to understand the change in the macrobenthic communities, the focus has primarily been shifted towards faster results to track down the changes from the prior environments. Therefore, studying the complete benthos faunal diversity of an area leads to an unrealistic approach. Thus, researchers tend to depend on various sampling gears, which ease the work capacity. The present study compared two samplings gears (core and quadrate) in two different habitats to understand the diversity of the macrobenthic communities. In terms of abundance, the core gear showed higher significant differences as compared to quadrate. However, the gears did not significantly differ among the diversity indices (Margalef's index and Shannon- Winer index) and the cluster analysis (Bray-Curtis similarity index and nMDS). The present study found that the 'information loss' was minimal with the aggregated data at a higher taxonomic level. Spearman rank correlation coefficient revealed that the information loss was low up to family-level and the correlation coefficient decreases as the taxonomic level increases after family-level. Nonetheless, the choice of sampling gears did not influence the diversity of the soft-bottom intertidal macrobenthic communities.

Intra-annual Variability in Hawaiian Shallow-water, Soft-bottom Macrobenthic Communities Adjacent to a Eutrophic Estuary

2000 ◽  
Vol 50 (2) ◽  
pp. 245-258 ◽  
Author(s):  
S.A. Mccarthy ◽  
E.A. Laws ◽  
W.A. Estabrooks ◽  
J.H. Bailey-Brock ◽  
E.A. Kay
Keyword(s):  
Shallow Water ◽  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Annual Variability

Soft bottom macrobenthic communities in a semi-enclosed Bay bordering the English Channel: The Rade de Cherbourg

2017 ◽  
Vol 9 ◽  
pp. 106-116 ◽  
Author(s):  
Noémie Baux ◽  
Jean-Philippe Pezy ◽  
Quentin Bachelet ◽  
Alexandrine Baffreau ◽  
Yann Méar ◽  
...  
Keyword(s):  
English Channel ◽  
Soft Bottom ◽  
Macrobenthic Communities ◽  
Enclosed Bay

Distribution of soft bottom macrobenthic communities in tropical marinas of Singapore

2019 ◽  
Vol 22 (3) ◽  
pp. 443-453 ◽  
Author(s):  
Chin Soon Lionel Ng ◽  
Kok Ben Toh ◽  
Tai Chong Toh ◽  
Juat Ying Ng ◽  
Pei Rong Cheo ◽  
...  
Keyword(s):  
Soft Bottom ◽  
Macrobenthic Communities

scholarly journals Bivalve mollusk assemblages on São Paulo's northern continental shelf, southeast Brazil

2005 ◽  
Vol 65 (4) ◽  
pp. 717-727 ◽  
Author(s):  
A. Soares-Gomes ◽  
A. M. S. Pires-Vanin
Keyword(s):  
Clustering Analysis ◽  
Biological Diversity ◽  
Permutation Test ◽  
Anthropogenic Activities ◽  
Austral Summer ◽  
Trophic Groups ◽  
Depth Gradient ◽  
Soft Bottom ◽  
Analysis Of Similarity ◽  
Mollusc Assemblages

Soft bottom bivalve mollusc assemblages were sampled along a depth gradient (10 to 100 m) on the northern São Paulo shelf during the austral summer and winter. A one-way analysis of similarity permutation test revealed there was no seasonal difference in the structure of the bivalve assemblages in the area. A clustering analysis indicated 3 groups of stations corresponding to the bathymetric gradient. Both K-dominance curves and Shannon and Pielou indexes showed higher biological diversity and higher evenness for the shallower area. Most of the bivalves found were classified as suspension-feeders, co-occurring with deposit-feeder species, suggesting an absence of negative interactions between these trophic groups. Differences in the frequency of disturbance along the depth gradient caused by wave storms - more common in winter - and also by predation and anthropogenic activities, such as dredging of fishing boats and input of gross sewage, likely explain the higher diversity found on the inner shelf of Ubatuba.

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