scholarly journals Temporal change of the environmental conditions of the sediment and abundance of the nematode community in the subtidal sediment near a river mouth with tidal flats

2006 ◽  
Vol 1 (2) ◽  
pp. 109-116 ◽  
Author(s):  
Supaporn Yodnarasri ◽  
Kuninao Tada ◽  
Shigeru Montani
Keyword(s):  
Environmental Conditions ◽  
Temporal Change ◽  
River Mouth ◽  
Tidal Flats ◽  
Nematode Community

The influence of environmental conditions and hydrologic connectivity on cyanobacteria assemblages in two drowned river mouth lakes

2011 ◽  
Vol 37 (3) ◽  
pp. 470-479 ◽  
Author(s):  
Liqiang Xie ◽  
Janel Hagar ◽  
Richard R. Rediske ◽  
James O'Keefe ◽  
Julianne Dyble ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
River Mouth ◽  
Hydrologic Connectivity

scholarly journals Bacterivory of a mudflat nematode community under different environmental conditions

2008 ◽  
Vol 154 (4) ◽  
pp. 671-682 ◽  
Author(s):  
Pierre-Yves Pascal ◽  
Christine Dupuy ◽  
Pierre Richard ◽  
Jadwiga Rzeznik-Orignac ◽  
Nathalie Niquil
Keyword(s):  
Environmental Conditions ◽  
Nematode Community

scholarly journals Population Dynamics of a Clam, Ruditapes philippinarum, on an Artificially-created Sand Cover on the Tidal Flats at the River Mouth of Midorikawa River.

2002 ◽  
Vol 57 ◽  
pp. 177-187 ◽  
Author(s):  
Hiroaki TSUTSUMI ◽  
Kouko ISHIZAWA ◽  
Miho TOMISHIGE ◽  
Midori MORIYAMA ◽  
Kaori SAKAMOTO ◽  
...  
Keyword(s):  
Population Dynamics ◽  
River Mouth ◽  
Ruditapes Philippinarum ◽  
Tidal Flats

scholarly journals Unique Habitat for Benthic Foraminifera in Subtidal Blue Holes on Carbonate Platforms

2021 ◽  
Vol 9 ◽  
Author(s):  
Shawna N. Little ◽  
Peter J. van Hengstum ◽  
Patricia A. Beddows ◽  
Jeffrey P. Donnelly ◽  
Tyler S. Winkler ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Tidal Flats ◽  
Benthic Habitat ◽  
Carbonate Platforms ◽  
The Bahamas ◽  
Blue Hole ◽  
Hydrographic Conditions ◽  
Sea Level Oscillations ◽  
Karst Landscapes ◽  
Blue Holes

Dissolution of carbonate platforms, like The Bahamas, throughout Quaternary sea-level oscillations have created mature karst landscapes that can include sinkholes and off-shore blue holes. These karst features are flooded by saline oceanic waters and meteoric-influenced groundwaters, which creates unique groundwater environments and ecosystems. Little is known about the modern benthic meiofauna, like foraminifera, in these environments or how internal hydrographic characteristics of salinity, dissolved oxygen, or pH may influence benthic habitat viability. Here we compare the total benthic foraminiferal distributions in sediment-water interface samples collected from <2 m water depth on the carbonate tidal flats, and the two subtidal blue holes Freshwater River Blue Hole and Meredith’s Blue Hole, on the leeward margin of Great Abaco Island, The Bahamas. All samples are dominated by miliolid foraminifera (i.e., Quinqueloculina and Triloculina), yet notable differences emerge in the secondary taxa between these two environments that allows identification of two assemblages: a Carbonate Tidal Flats Assemblage (CTFA) vs. a Blue Hole Assemblage (BHA). The CTFA includes abundant common shallow-water lagoon foraminifera (e.g., Peneroplis, Rosalina, Rotorbis), while the BHA has higher proportions of foraminifera that are known to tolerate stressful environmental conditions of brackish and dysoxic waters elsewhere (e.g., Pseudoeponides, Cribroelphidium, Ammonia). We also observe how the hydrographic differences between subtidal blue holes can promote different benthic habitats for foraminifera, and this is observed through differences in both agglutinated and hyaline fauna. The unique hydrographic conditions in subtidal blue holes make them great laboratories for assessing the response of benthic foraminiferal communities to extreme environmental conditions (e.g., low pH, dysoxia).

Amazon Sediment Transport and Accumulation Along the Continuum of Mixed Fluvial and Marine Processes

2021 ◽  
Vol 13 (1) ◽  
pp. 501-536
Author(s):  
Charles A. Nittrouer ◽  
David J. DeMaster ◽  
Steven A. Kuehl ◽  
Alberto G. Figueiredo ◽  
Richard W. Sternberg ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Environmental Conditions ◽  
Sediment Accumulation ◽  
River Mouth ◽  
Tidal River ◽  
Mangrove Forests ◽  
Future Change ◽  
Estuarine Processes ◽  
Sediment Transfer ◽  
The Continuum

Sediment transfer from land to ocean begins in coastal settings and, for large rivers such as the Amazon, has dramatic impacts over thousands of kilometers covering diverse environmental conditions. In the relatively natural Amazon tidal river, combinations of fluvial and marine processes transition toward the ocean, affecting the transport and accumulation of sediment in floodplains and tributary mouths. The enormous discharge of Amazon fresh water causes estuarine processes to occur on the continental shelf, where much sediment accumulation creates a large clinoform structure and where additional sediment accumulates along its shoreward boundary in tidal flats and mangrove forests. Some remaining Amazon sediment is transported beyond the region near the river mouth, and fluvial forces on it diminish. Numerous perturbations to Amazon sediment transport and accumulation occur naturally, but human actions will likely dominate future change, and now is the time to document, understand, and mitigate their impacts.

scholarly journals Temporal variability of live (stained) benthic foraminiferal faunas in a river-dominated shelf – faunal response to rapid changes of the river influence (Rhône prodelta, NW Mediterranean)

2011 ◽  
Vol 8 (5) ◽  
pp. 9033-9086 ◽  
Author(s):  
A. Goineau ◽  
C. Fontanier ◽  
F. Jorissen ◽  
R. Buscail ◽  
P. Kerhervé ◽  
...  
Keyword(s):  
Organic Matter ◽  
Environmental Conditions ◽  
Spring Bloom ◽  
River Mouth ◽  
Rhône River ◽  
Faunal Composition ◽  
Wide Range ◽  
Rhone River ◽  
River Flood ◽  
Nw Mediterranean

Abstract. In the context of the French research project CHACCRA (Climate and Human-induced Alterations in Carbon Cycling at the River–seA connection), living (rose Bengal-stained) benthic foraminifera were investigated at two stations (24 and 67 m depth) in the Rhône prodelta (NW Mediterranean, Gulf of Lions). The aim of this study was to precise the response of benthic foraminiferal faunas to temporal changes of the Rhône River inputs (e.g. organic and terrigeneous material). Each site was sampled in April 2007, September 2007, May 2008 and December 2008, permitting to observe foraminiferal faunas of the 63–150 and >150 μm size fractions under a wide range of environmental conditions. Obvious variations in foraminiferal faunal composition were observed during the four investigated periods at the shallowest Station A located in the close vicinity of the Rhône River mouth. Different colonisation stages were observed after major Rhône River flood events, foraminiferal faunas responding with an opportunistic strategy few days to weeks after the creation of a peculiar sedimentary environment (Leptohalysis scottii, May 2008) or high amounts of organic matter supplied by a river flood (Ammonia tepida, December 2008). Under more stable conditions, relatively diverse and equilibrated faunas grew in the sediments. Species benefited from noticeable input of riverine phytodetritus to the sediment during spring bloom conditions (April 2007; e.g. Bolivina dilatata, Nonionella stella, Stainforthia fusiformis), or high amounts of still bio-available organic matter under more oligotrophic conditions (September 2007; e.g. Ammonia tepida, Psammosphaera fusca). The reduced influence of the Rhône River input at the farther Station N led to less contrasted environmental conditions during the four sampling periods, and so to less obvious variations in foraminiferal faunal composition. During reduced riverine influence (i.e. low Rhône discharge), species able to feed on fresh phytodetritus (e.g. Clavulina cylindrica, Hopkinsina atlantica, Nonionella iridea and Nonionella turgida) benefited from eutrophic conditions of the spring bloom (April 2007, May 2008). Conversely, the occurrence of Nouria polymorphinoides under oligotrophic conditions (September 2007, December 2008) was indicative of a benthic environment potentially disturbed by bottom currents. This study put into evidence the extremely rapid response of benthic foraminiferal faunas to strong variations in environmental conditions, especially close to the river mouth (Station A), response noticeably reduced farther from the mouth (Station N) due to a weaker impact of riverine input.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Sign in / Sign up

Export Citation Format

Share Document