Gill Ventilation and the Role of Reversed Respiratory Currents in Carcinus Maenas (L.)

1964 ◽  
Vol 41 (2) ◽  
pp. 299-307
Author(s):  
K. D. ARUDPRAGASAM ◽  
E. NAYLOR
Keyword(s):  
Carbon Dioxide ◽  
Shallow Water ◽  
High Tide ◽  
Carcinus Maenas ◽  
Oxygen Depletion ◽  
Excess Carbon ◽  
Gill Chamber ◽  
Gill Ventilation ◽  
Carbon Dioxide Accumulation

1. A method is described for obtaining continuous records of the direction of flow of the respiratory current of Carcinus by recording changes of pressure in the gill chamber. 2. Frequent and rhythmic reversals of the normally forward-flowing respiratory current appear to irrigate the upper surfaces of the posterior gills and do not serve primarily to clean the gills. 3. The rate of reversal of this respiratory current increases spontaneously at times of high tide. It decreases under conditions of carbon-dioxide accumulation and increases under conditions of oxygen depletion in the absence of excess carbon dioxide. 4. The pattern of gill ventilation varies according to whether crabs are totally in water, partially buried in sand, or in very shallow water.

Gill Ventilation Volumes, Oxygen Consumption and Respiratory Rhythms in Carcinus Maenas (L.)

1964 ◽  
Vol 41 (2) ◽  
pp. 309-321
Author(s):  
K. D. ARUDPRAGASAM ◽  
E. NAYLOR
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Prolonged Exposure ◽  
Respiratory Activity ◽  
Carcinus Maenas ◽  
Oxygen Depletion ◽  
Decapod Crustacea ◽  
Gill Ventilation ◽  
Respiratory Rhythms ◽  
Pumping Activity

1. An apparatus is described for continuously measuring gill ventilation volumes in crabs. 2. Large Carcinus pump about 1 c.c./g./min. and consume oxygen at the rate of about 0.03 c.c./g./hr. whilst smaller specimens pump up to 1.5 c.c./g./min. and consume up to 0.1 c.c./g./hr. Freshly collected crabs show persistent tidal and 24 hr. rhythms of pumping activity and oxygen consumption. 3. In response to oxygen depletion Carcinus shows increased rates of gill ventilation and increased percentage utilization. Prolonged exposure to increased carbon dioxide results in a short-lived inhibition followed by over-compensation and then progressive inhibition of respiratory activity. 4. The results are discussed in relation to previous work on respiration in other decapod Crustacea.

scholarly journals Modeling the marine aragonite cycle: changes under rising carbon dioxide and its role in shallow water CaCO<sub>3</sub> dissolution

2008 ◽  
Vol 5 (4) ◽  
pp. 1057-1072 ◽  
Author(s):  
R. Gangstø ◽  
M. Gehlen ◽  
B. Schneider ◽  
L. Bopp ◽  
O. Aumont ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Shallow Water ◽  
Biogeochemical Model ◽  
Subsequent Reduction ◽  
Saturation State ◽  
Carbonate Production ◽  
Mesozooplankton Biomass ◽  
Marine Carbonate ◽  
Realistic Representation

Abstract. The marine aragonite cycle has been included in the global biogeochemical model PISCES to study the role of aragonite in shallow water CaCO3 dissolution. Aragonite production is parameterized as a function of mesozooplankton biomass and aragonite saturation state of ambient waters. Observation-based estimates of marine carbonate production and dissolution are well reproduced by the model and about 60% of the combined CaCO3 water column dissolution from aragonite and calcite is simulated above 2000 m. In contrast, a calcite-only version yields a much smaller fraction. This suggests that the aragonite cycle should be included in models for a realistic representation of CaCO3 dissolution and alkalinity. For the SRES A2 CO2 scenario, production rates of aragonite are projected to notably decrease after 2050. By the end of this century, global aragonite production is reduced by 29% and total CaCO3 production by 19% relative to pre-industrial. Geographically, the effect from increasing atmospheric CO2, and the subsequent reduction in saturation state, is largest in the subpolar and polar areas where the modeled aragonite production is projected to decrease by 65% until 2100.

scholarly journals Modeling the marine aragonite cycle: changes under rising carbon dioxide and its role in shallow water CaCO<sub>3</sub> dissolution

2008 ◽  
Vol 5 (2) ◽  
pp. 1655-1687
Author(s):  
R. Gangstø ◽  
M. Gehlen ◽  
B. Schneider ◽  
L. Bopp ◽  
O. Aumont ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Shallow Water ◽  
Biogeochemical Model ◽  
Subsequent Reduction ◽  
Saturation State ◽  
Carbonate Production ◽  
Mesozooplankton Biomass ◽  
Marine Carbonate ◽  
Realistic Representation

Abstract. The marine aragonite cycle has been included in the global biogeochemical model PISCES to study the role of aragonite in shallow water CaCO3 dissolution. Aragonite production is parameterized as a function of mesozooplankton biomass and aragonite saturation state of ambient waters. Observation-based estimates of marine carbonate production and dissolution are well reproduced by the model and about 60% of the combined CaCO3 water column dissolution from aragonite and calcite is simulated above 2000 m. In contrast, a calcite-only version yields a much smaller fraction. This suggests that the aragonite cycle should be included in models for a realistic representation of CaCO3 dissolution and alkalinity. For the SRES A2 CO2 scenario, production rates of aragonite are projected to notably decrease after 2050. By the end of this century, global aragonite production is reduced by almost one third and total CaCO3 production by 19% relative to pre-industrial. Geographically, the effect from increasing atmospheric CO2, and the subsequent reduction in saturation state, is largest in the subpolar and polar areas where the modeled aragonite production is projected to decrease by 65% until 2100.

Towards Control of an Estuary

1987 ◽  
Vol 19 (9) ◽  
pp. 155-174
Author(s):  
Henk L. F. Saeijs
Keyword(s):  
Shallow Water ◽  
Storm Surge ◽  
Salt Marshes ◽  
Large Scale ◽  
Western Europe ◽  
Oxygen Depletion ◽  
Negative Effects ◽  
Intertidal Flats ◽  
Environmental Consequences ◽  
Short Time

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.

Unraveling the Role of Zinc on Bimetallic Fe5C2–ZnO Catalysts for Highly Selective Carbon Dioxide Hydrogenation to High Carbon α-Olefins

ACS Catalysis ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2121-2133
Author(s):  
Chao Zhang ◽  
Chenxi Cao ◽  
Yulong Zhang ◽  
Xianglin Liu ◽  
Jing Xu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Carbon ◽  
Carbon Dioxide Hydrogenation
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