Disturbances in soft sediments due to piston coring

1978 ◽  
Vol 28 (1-2) ◽  
pp. 135-144 ◽  
Author(s):  
D.A.V. Stow ◽  
A.E. Aksu
Keyword(s):  
Soft Sediments

A comparison of some rapid techniques for the measurement of density in soft sediments

Sedimentology ◽  
1986 ◽  
Vol 33 (5) ◽  
pp. 777-781 ◽  
Author(s):  
J. HILTON ◽  
J. P. LISHMAN ◽  
A. MILLINGTON
Keyword(s):  
Soft Sediments

The Forests of South Viet Nam in 1971–72: A Personal Account

1984 ◽  
Vol 11 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Paul W. Richards
Keyword(s):  
Aerial Photography ◽  
Viet Nam ◽  
Mangrove Forests ◽  
Military Operations ◽  
Personal Account ◽  
Soft Sediments ◽  
The Us ◽  
Academy Of Sciences

An account is given of the work on the forests of Viet Nam of the US Academy of Sciences' Committee on the Effects of Herbicides in South Viet Nam during 1971–74. Owing to the insecure state of the country at the time, very little work on the ground was possible. The Committee's conclusions had therefore to depend largely on observations from the air and aerial photography, and were subject to considerable errors.The appearance after herbicide spraying of the Inland and mangrove forests as seen from the air in 1971 and 1972 is described. In the Inland forest most of the emergent trees were killed, but much of the undergrowth remained alive. In addition to the effects of herbicides, the Inland forests suffered widespread damage from bombing and other military operations. In the mangrove forests, herbicide spraying destroyed almost the whole biomass, resulting in the complete denudation of vast areas of soft sediments.

Molecular phylogeny of Clibanarius Dana, 1852 from the Indo-West Pacific: evolution of pereopod colour pattern and habitat adaptation

Crustaceana ◽  
2019 ◽  
Vol 92 (7) ◽  
pp. 799-839 ◽  
Author(s):  
Akihiro Yoshikawa ◽  
Kazuho Ikeo ◽  
Junichi Imoto ◽  
Wachirah Jaingam ◽  
Lily Surayya Eka Putri ◽  
...  
Keyword(s):  
Histone H3 ◽  
Hermit Crabs ◽  
Colour Pattern ◽  
12S Rrna ◽  
Habitat Adaptation ◽  
Soft Sediments ◽  
Mitochondrial 12S Rrna ◽  
Nuclear Histone ◽  
Colour Patterns ◽  
Hard Substrates

Abstract Species of hermit crabs in the genus Clibanarius Dana, 1852 have adapted to various environments in the intertidal areas, including hard substrates and soft sediments. These species often bear a close morphological resemblance to each other, therefore, the colouration on the pereopods can be one of the reliable characteristics to distinguish the species. However, the evolutionary relationships among species with different colour patterns and relationships between colour patterns and habitat adaptation have not previously been investigated. Therefore, we reconstructed the phylogenetic relationships among 19 species of Clibanarius based on mitochondrial [12S rRNA, 16S rRNA and cytochrome oxidase I] and nuclear [histone H3] DNA markers. The results suggest that the striped and solid colour elements have evolved multiple times independently, with the ancestral colour pattern potentially being scattered, bright colour spots with a bright colour band. Our findings also suggest that evolutionary adaptation from hard substrates to mudflats and soft sediments may have occurred at least twice.

Heavy metal pollution and macrobenthic assemblages in soft sediments in two Sydney estuaries, Australia

1998 ◽  
Vol 49 (6) ◽  
pp. 533 ◽  
Author(s):  
Jonathan S. Stark
Keyword(s):  
Heavy Metals ◽  
Environmental Variables ◽  
Spatial Scales ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soft Sediments ◽  
Lead And Zinc ◽  
Macrobenthic Assemblages ◽  
Order Of Magnitude ◽  
Copper Lead

The influence of heavy metals (copper, lead and zinc) associated with urban runoff, on assemblages of macrofauna in intertidal soft sediments was studied in two estuaries in the Sydney region. The patterns of distribution and abundance of fauna and assemblages was found to vary significantly at several spatial scales: within bays in an estuary, between bays within an estuary and between bays from different estuaries. Significant differences were found in concentrations of heavy metals in sediments, but there was very little difference among bays in other environmental variables: grain-size characteristics and organic matter content of sediments. Bays polluted by heavy metals had significantly different assemblages to unpolluted bays, were generally less diverse and were characterized by an order-of-magnitude greater abundance of capitellids, spionids, nereids and bivalves. Unpolluted bays had greater abundance of crustaceans and several polychaete families, including paraonids and nephtyids and were generally more diverse. There was a significant correlation between patterns of assemblages and concentrations of heavy metals, but not with other environmental variables.

Trampling experiments on bones in fine and soft sediments

Quaternaire ◽  
2018 ◽  
pp. 39-44 ◽  
Author(s):  
Lee Rozada ◽  
Ronan Allain ◽  
Jean‑François Tournepiche
Keyword(s):  
Soft Sediments

scholarly journals Comparison of mechanical disturbance in soft sediments due to tickler-chain SumWing trawl vs. electro-fitted PulseWing trawl

2018 ◽  
Vol 76 (1) ◽  
pp. 312-329 ◽  
Author(s):  
Jochen Depestele ◽  
Koen Degrendele ◽  
Moosa Esmaeili ◽  
Ana Ivanović ◽  
Silke Kröger ◽  
...  
Keyword(s):  
Particle Size ◽  
Penetration Depth ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Strength Analysis ◽  
Sediment Profile ◽  
Soft Sediments ◽  
Sediment Layers ◽  
Micro Topography ◽  
Seabed Roughness

Abstract Tickler-chain SumWing and electrode-fitted PulseWing trawls were compared to assess seabed impacts. Multi-beam echo sounder (MBES) bathymetry confirmed that the SumWing trawl tracks were consistently and uniformly deepened to 1.5 cm depth in contrast to 0.7 cm following PulseWing trawling. MBES backscatter strength analysis showed that SumWing trawls (3.11 dB) flattened seabed roughness significantly more than PulseWing trawls (2.37 dB). Sediment Profile Imagery (SPI) showed that SumWing trawls (mean, SD) homogenised the sediment deeper (3.4 cm, 0.9 cm) and removed more of the oxidised layer than PulseWing trawls (1 cm, 0.8 cm). The reduced PulseWing trawling impacts allowed a faster re-establishment of the oxidised layer and micro-topography. Particle size analysis suggested that SumWing trawls injected finer particles into the deeper sediment layers (∼4 cm depth), while PulseWing trawling only caused coarsening of the top layers (winnowing effect). Total penetration depth (mean, SD) of the SumWing trawls (4.1 cm, 0.9 cm) and PulseWing trawls (1.8 cm, 0.8 cm) was estimated by the depth of the disturbance layer and the layer of mobilized sediment (SumWing = 0.7 cm; PulseWing trawl = 0.8 cm). PulseWing trawls reduced most of the mechanical seabed impacts compared to SumWing trawls for this substrate and area characteristics.

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