Some Aspects of the Ecology of Lake Macquarie, N.S.W., with Regard to an Alleged Depletion of Fish. VII. The Benthic Macrofauna.

1959 ◽  
Vol 10 (3) ◽  
pp. 341 ◽  
Author(s):  
RJ MacIntyre
Keyword(s):  
Deep Water ◽  
Benthic Macrofauna ◽  
Lake Area ◽  
Anaerobic Conditions ◽  
Mollusc Species ◽  
Recent Origin ◽  
Benthic Zone

The benthic zone of Lake Macquarie, passing from shallow to deep water, consists of weed, slope, and mud zones, occupying respectively 23.5, 16.0, and 60.5 per cent. of the lake area. The biomasses of the invertebrate macrofauna of the zones are respectively 94 156 g, 180 � 12 g, and 10.6 � 9.4 g per m2. Each zone has its typical fauna. A variety of species occurs in the weed and slope zones, but only two species occur in number in the mud zone. A number of mollusc species was represented only by dead shells of recent origin, suggesting some catastrophe such as production of anaerobic conditions. There is no evidence that the mussel Trichomya hirsuta was affected, and experimentation revealed that this species can survive long periods of immersion under anaerobic conditions.

An Epibenthic Sledge for Operations on Marine Soft Bottom and Bedrock

2005 ◽  
Vol 39 (2) ◽  
pp. 10-21 ◽  
Author(s):  
Nils Brenke
Keyword(s):  
Deep Water ◽  
Mechanical Stability ◽  
Benthic Macrofauna ◽  
Soft Bottom ◽  
Epibenthic Sledge ◽  
Marine Habitats ◽  
Antarctic Waters ◽  
First Results ◽  
Steep Slopes ◽  
High Mechanical Stability

A multi-purpose epibenthic sledge, designed for sampling of small benthic macrofauna in marine habitats and at any navigable depth, is presented. The new epibenthic sledge operates reliably on soft sediments in shallow and in open oceanic deep water, as well as on steep slopes, between rocks and glacier moraines as frequently found in Antarctic waters, and on primary hard substrate. The construction is of high mechanical stability with fully protected nets. In case of damage, parts of the sledge can be replaced or repaired easily on board. A description of the gear with a detailed construction plan, as well as parameters for handling in diverse marine habitats, is given. Calculation of the towing distance and first results with possible sources of errors are discussed.

Shelf and deep-water benthic macrofauna assemblages from the western Gulf of Mexico: temporal dynamics and environmental drivers

2021 ◽  
pp. 105241
Author(s):  
Iván Hernández-Ávila ◽  
Daniel Pech ◽  
Frank A. Ocaña ◽  
Flor Árcega-Cabrera ◽  
Cecilia Enríquez
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Temporal Dynamics ◽  
Benthic Macrofauna ◽  
Environmental Drivers

Designing Constructed Wetlands for Nitrogen Removal

1994 ◽  
Vol 29 (4) ◽  
pp. 15-27 ◽  
Author(s):  
Donald A. Hammer ◽  
Robert L. Knight
Keyword(s):  
Constructed Wetlands ◽  
Deep Water ◽  
Anaerobic Conditions ◽  
Loading Rates ◽  
The North ◽  
N Removal ◽  
North American Data ◽  
Natural Wetlands ◽  
Low Levels ◽  
Aerobic And Anaerobic

Many constructed wetlands adequately treat BOD5, TSS, and bacteria. However, a review of nitrogen (N) data from 52 constructed and natural wetlands in the North American data base confirmed that N removal was variable. Nitrification and denitrification require aerobic and anaerobic conditions. This paper presents case histories of systems that use alternating shallow and deep water zones to create both environments. Regression analysis of N removal and N loadings in 18 shallow-deep water systems suggested that NH4+ loading (kg N/ha/day) could be used to predict effluent NH4+ values. Combinations of shallow water-emergent vegetation and deep water-submergent vegetation with low NH4+ (and TKN) loading rates can produce very low levels of discharged NH4+.

scholarly journals Moluscos de la expedición del RIV Edwin Link en las costas del Caribe mexicano

2015 ◽  
pp. 625-631
Author(s):  
Norma Emilia González
Keyword(s):  
Deep Water ◽  
Marine Mollusc ◽  
Mexican Caribbean ◽  
Mollusc Species

A checklist of marine mollusc species mainly from deep-water localities off Mexican Caribbean shores is pre­ sented.Samples were obtained with a mechanical arm in 2-307 m during the. expedition of (hé RIV "Edwin Link", August 1990; the listinclud¡:s 59 species of Oastropoda, 17 species of Bivalvia, tbree species of Scaphopoda and three species of Polyplacophóra.

The fauna of the mid-Atlantic islands

1960 ◽  
Vol 152 (949) ◽  
pp. 550-567 ◽  
Keyword(s):  
Deep Water ◽  
Oceanic Islands ◽  
Temperate Zone ◽  
The Other ◽  
Cinder Cones ◽  
Tristan Da Cunha ◽  
Gough Island ◽  
Central Cone ◽  
Recent Origin ◽  
Historic Record

Tristan da Cunha, Nightingale, Inaccessible, and Gough Islands are the only Atlantic oceanic islands lying within the southern cold temperate zone. Their relative positions, and the situation of the group as a whole, are shown in figure 49. All of them are volcanic, and probably initially of Tertiary age (Dunne 1941; Le Maitre 1959). There is no historic record of activity but Tristan retains a central cone and well-preserved lateral cinder cones which appear of recent origin. Undated ash bands occur in the peats of this island, and a small, rather broken cone (Edinburgh Peak) on Gough Island may have been the source of an ash band in peat dated by the radiocarbon method as 2345 ± 130 years old (Hafsten, this Discussion). The other two islands show no trace of recent volcanicity. All the members of the group rise steeply from deep water, and there is no sign of previous land links between them

Impact of deep-water fish farms on benthic macrofauna communities under different hydrodynamic conditions

2015 ◽  
Vol 101 (2) ◽  
pp. 776-783 ◽  
Author(s):  
Thomas Valdemarsen ◽  
Pia Kupka Hansen ◽  
Arne Ervik ◽  
Raymond J. Bannister
Keyword(s):  
Deep Water ◽  
Benthic Macrofauna ◽  
Hydrodynamic Conditions ◽  
Fish Farms ◽  
Water Fish ◽  
Macrofauna Communities

scholarly journals Oxygen and evolutionary patterns in the sea: Onshore/offshore trends and recent recruitment of deep-sea faunas

1998 ◽  
Vol 95 (16) ◽  
pp. 9396-9401 ◽  
Author(s):  
David K. Jacobs ◽  
David R. Lindberg
Keyword(s):  
Deep Water ◽  
Deep Sea ◽  
Marine Invertebrates ◽  
Benthic Organisms ◽  
Evolutionary Patterns ◽  
Higher Taxa ◽  
Early Mesozoic ◽  
Recent Origin ◽  
Global Events

Over the last 15 years a striking pattern of diversification has been documented in the fossil record of benthic marine invertebrates. Higher taxa (orders) tend to originate onshore, diversify offshore, and retreat into deep-water environments. Previous studies attribute this macroevolutionary pattern to a variety of causes, foremost among them the role of nearshore disturbance in providing opportunities for the evolution of novel forms accorded ordinal rank. Our analysis of the post-Paleozoic record of ordinal first appearances indicates that the onshore preference of ordinal origination occurred only in the Mesozoic prior to the Turonian stage of the Cretaceous, a period characterized by relatively frequent anoxic/dysoxic bottom conditions in deeper marine environments. Later, in the Cretaceous and Cenozoic, ordinal origination of benthic organisms did not occur exclusively, or even preferentially, in onshore environments. This change in environmental pattern of ordinal origination roughly correlates with Late Cretaceous: (i) decline in anoxia/dysoxia in offshore benthic environments; (ii) extinction of faunas associated with dysoxic conditions; (iii) increase in bioturbation with the expansion of deep burrowing forms into offshore environments; and (iv) offshore expansion of bryozoan diversity. We also advance a separate argument that the Cenomanian/Turonian and latest Paleocene global events eliminated much of the deep-water benthos. This requires a more recent origin of modern vent and deep-sea faunas, from shallower water refugia, than the Paleozoic or early Mesozoic origin of these faunas suggested by other workers.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

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