The Mechanism of Fluid Absorption at Ecdysis in the American Lobster Homarus Americanus

1980 ◽  
Vol 84 (1) ◽  
pp. 89-102 ◽  
Author(s):  
DONALD L. MYKLES
Keyword(s):  
Digestive Tract ◽  
Water Uptake ◽  
Principal Part ◽  
Sea Water ◽  
Homarus Americanus ◽  
Barium Sulphate ◽  
American Lobster ◽  
Water Fluxes ◽  
Fluid Absorption

1. The mechanism of fluid absorption at ecdysis was investigated in the stenohaline marine decapod, Homarus americanus. 2. Sea-water uptake began approximately 1 h before ecdysis, increased rapidly during ecdysis, and was completed 2 h after ecdysis. 3. Increased drinking rates were measured during and just after ecdysis. The quantity of water ingested was equal to the total amount of water absorbed during moult, indicating that fluid entered the haemolymph exclusively via the lining of the digestive tract. 4. It was estimated that 91 % of the ingested sea water appeared in the haemolymph by 2·5 h postecdysis. 5. The midgut appeared to be the principal part of the digestive tract involved in the absorption of fluid into the haemolymph. X-radiography of lobsters that ingested a suspension of barium sulphate during ecdysis demonstrated that accumulation and concentration of this compound occurred within the midgut during the 2·5 h of haemolymph expansion following ecdysis. Elevated net water fluxes across perfused midgut were observed in late proecdysis and 0·5 h after ecdysis.

scholarly journals Stationary and Nonstationary Ion and Water Flux Interactions in Kidney Proximal Tubule: Mathematical Analysis of Isosmotic Transport by a Minimalistic Model

2019 ◽  
pp. 101-147 ◽  
Author(s):  
Erik Hviid Larsen ◽  
Jens Nørkær Sørensen
Keyword(s):  
Water Uptake ◽  
Time Course ◽  
Epithelial Transport ◽  
Water Flux ◽  
Experimental Studies ◽  
Physiological Parameter ◽  
Water Fluxes ◽  
Fluid Absorption ◽  
Knock Out ◽  
Osmotic Permeability

AbstractOur mathematical model of epithelial transport (Larsen et al. Acta Physiol. 195:171–186, 2009) is extended by equations for currents and conductance of apical SGLT2. With independent variables of the physiological parameter space, the model reproduces intracellular solute concentrations, ion and water fluxes, and electrophysiology of proximal convoluted tubule. The following were shown: Water flux is given by active Na+ flux into lateral spaces, while osmolarity of absorbed fluid depends on osmotic permeability of apical membranes. Following aquaporin “knock-out,” water uptake is not reduced but redirected to the paracellular pathway. Reported decrease in epithelial water uptake in aquaporin-1 knock-out mouse is caused by downregulation of active Na+ absorption. Luminal glucose stimulates Na+ uptake by instantaneous depolarization-induced pump activity (“cross-talk”) and delayed stimulation because of slow rise in intracellular [Na+]. Rate of fluid absorption and flux of active K+ absorption would have to be attuned at epithelial cell level for the [K+] of the absorbate being in the physiological range of interstitial [K+]. Following unilateral osmotic perturbation, time course of water fluxes between intraepithelial compartments provides physical explanation for the transepithelial osmotic permeability being orders of magnitude smaller than cell membranes’ osmotic permeability. Fluid absorption is always hyperosmotic to bath. Deviation from isosmotic absorption is increased in presence of glucose contrasting experimental studies showing isosmotic transport being independent of glucose uptake. For achieving isosmotic transport, the cost of Na+ recirculation is predicted to be but a few percent of the energy consumption of Na+/K+ pumps.

Growth of juvenile American lobster Homarus americanus in a changing environment

2016 ◽  
Vol 557 ◽  
pp. 177-187 ◽  
Author(s):  
MD McMahan ◽  
DF Cowan ◽  
Y Chen ◽  
GD Sherwood ◽  
JH Grabowski
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Changing Environment

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

Effect of long-term moisture exposure on impact response of glass-reinforced vinylester

2021 ◽  
pp. 147509022199616
Author(s):  
Fatemeh Alizadeh ◽  
Navid Kharghani ◽  
Carlos Guedes Soares
Keyword(s):  
Water Uptake ◽  
Failure Modes ◽  
Sea Water ◽  
Composite Plates ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Water Type ◽  
Interfacial Damage ◽  
Impact Properties ◽  
The Impact

Glass/Vinylester composite laminates are comprehensively characterised to assess its impact response behaviour under moisture exposure in marine structures. An instrumented drop weight impact machine is utilised to determine the impact responses of dry and immersed specimens in normal, salted and sea water. The specimens, which had three different thicknesses, were subjected to water exposure for a very long period of over 20 months before tested in a low-velocity impact experiment. Water uptake was measured primarily to study the degradation profiles of GRP laminates after being permeated by water. Matrix dissolution and interfacial damage observed on the laminates after prolonged moisture exposure while the absorption behaviour was found typically non-Fickian. The weight of the composite plates firstly increased because of water diffusion up to month 15 and then decreased due to matrix degradation. The specimens with 3, 6 and 9 mm thickness exhibited maximum water absorption corresponding to 2.6%, 0.7% and 0.5% weight gain, respectively. In general, the results indicated that water uptake and impact properties were affected by thickness and less by water type. Impact properties of prolonged immersed specimens reduced remarkably, and intense failure modes detected almost in all cases. The least sensitive to impact damage were wet specimens with 9 mm thickness as they indicated similar maximum load and absorbed energy for different impact energies.

Valorization of American lobster ( Homarus americanus ) cooking waters: preparation and characterization of a food ingredient

2021 ◽  
Author(s):  
Ariane Tremblay ◽  
Ronan Corcuff ◽  
Charles Goulet ◽  
Samuel B. Godefroy ◽  
Alain Doyen ◽  
...  
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Food Ingredient

Predicting the winning or losing of symmetrical contests in the American lobster Homarus americanus (Milne-Edwards)

1997 ◽  
Vol 217 (1) ◽  
pp. 19-29 ◽  
Author(s):  
C. Vye ◽  
J.S. Cobb ◽  
T. Bradley ◽  
J. Gabbay ◽  
A. Genizi ◽  
...  
Keyword(s):  
Homarus Americanus ◽  
American Lobster

The composition of the exoskeleton of two crustacea: The American lobster Homarus americanus and the edible crab Cancer pagurus

2007 ◽  
Vol 463 (1-2) ◽  
pp. 65-68 ◽  
Author(s):  
F. Boßelmann ◽  
P. Romano ◽  
H. Fabritius ◽  
D. Raabe ◽  
M. Epple
Keyword(s):  
Homarus Americanus ◽  
American Lobster ◽  
Cancer Pagurus
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