Bimodal breathing in the estuarine crab Chasmagnathus granulatus Dana 1851 — physiological and morphological studies (original) (raw)
Related papers
Aerial and aquatic respiration in the shore crab Carcinus maenas (L.)
Comparative Biochemistry and Physiology Part A: Physiology - COMP BIOCHEM PHYSIOL PHYSIOL, 1972
The mean rate of oxygen consumption of 2.8 g (dry weight) specimens of Cur&us muenus in air is 177 ~1 O,/hr. This rate represents approximateIy 76.5 per cent of the rate in water which was initialiy 231.3 ~1 O,/hr. Following reimmersion in sea water, the mean rate increased from its aerial level to 206.3 ~1 OJhr.
Aquatic Gas Exchange in the Freshwater/ Land Crab, Holthuisana Transversa
1983
Holthuisana transversa (von Martens), a freshwater/land crab from arid areas of Australia, is an efficient bimodal breather. In water, resting MO2 (1-65^molg"^" 1 ) and V w (lS^mlg" 1 h" 1 ) at 25°C were lower than in other aquatic crabs whilst percentage extraction of oxygen was quite high (47 %). MO2 was not regulated at low ambient PQ2 but could be increased at least three times during exercise. Normoxic P1O2 was low (18Torr) compared with other water-breathing crabs. The haemolymph contained haemocyanin which had a moderate affinity for oxygen (P50 = 8 -0 Torr) and carried over 90% of the oxygen transported. Oxygen content of postbranchial haemolymph was low (346^moll" 1 ). There was a small positive Bohr shift (log Pso/pH-0-33). The strategy of gas exchange in water is discussed and compared with that of aquatic crabs.
Zoomorphology, 1992
The terrestrial crabs Geograpsus grayi, Geograpsus crinipes, Cardisoma hirtipes and Gecarcoidea natalis have a reduced number of gills and show a reduced planar gill surface (SA) compared to aquatic species. Gill lamellae are stiffened and thickened (increasing blood/gas (BG) diffusion distances) and nodules maintain wide spacing between lamellae. Haemolymph is directed through the gill lamellae by rows of pillar cells and in the afferent region an intralamellar septum splits the haemolymph into two parallel networks. Gaps in the lines of pillar cells allow movement of haemolymph between adjacent channels. The afferent vessel distributes haemolymph to the lamella via a number of direct channels including the marginal canal and in large gills with the aid of a long, forked sinus which supplies the ventral and central regions of the lamellae. The marginal canal functions in both distribution and collection of haemolymph; the role varies with species. Potential flow-control sites were identified at the junctions between afferent and efferent areas and where the efferent channels enter the efferent branchial vessel. Each gill receives a branch from the sternal artery which supplies all the lamellae. Transport epithelia is the principal cell type in the gills of all species examined though its location varies between species, either being confined to certain gills or specific parts of the lamellae.
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2004
Amphibious crabs, Cardisoma guanhumi, were acclimated to breathing either air or water and exposed to altered levels of oxygen and/or carbon dioxide in the medium. Hypercapnia (22, 36 and 73 torr CO 2) stimulated a significant hypercapnic ventilatory response (HCVR) in both groups of crabs, with a much greater effect on scaphognathite frequency (Df SC = + 700%) in air-breathing crabs than water-breathing crabs (Df SC = + 100%). In contrast, hyperoxia induced significant hypoventilation in both sets of crabs. However, simultaneous hyperoxia and hypercapnia triggered a greater than 10-fold increase in f SC in air-breathing crabs but no change in water-breathing crabs. For water-breathing crabs hypoxia simultaneous with hypercapnia triggered the same response as hypoxia alone-bradycardia (À 50%), and a significant increase in f SC at moderate exposures but not at the more extreme levels. The response of air-breathing crabs to hypoxia concurrent with hypercapnia was proportionally closer to the response to hypercapnia alone than to hypoxia. Thus, C. guanhumi were more sensitive to ambient CO 2 than O 2 when breathing air, characteristic of fully terrestrial species, and more sensitive to ambient O 2 when breathing water, characteristic of fully aquatic species. C. guanhumi possesses both an O 2-and a CO 2-based ventilatory drive whether breathing air or water, but the relative importance switches when the respiratory medium is altered.
Aerial Gas Exchange in Australian Freshwater/Land Crabs of the Genus Holthuisana
1983
SUMMARY Holthuisana valentula Riek and H. agassizi (Rathbun) both ventilate their lungs by lateral oscillations of the thoracic walls within the branchial chambers. Air enters and leaves the lungs via the prebranchial apertures and the Milne-Edwards apertures. At rest, active ventilation in H. transversa was low (0-95 mlg~^ h" 1 ) and a high diffusional component was evident. After disturbance,
Carbon dioxide excretion in the land crab (Cardisoma carnifex)
Journal of Experimental Zoology, 1981
The hemolymph of Cardisoma carnifex shows a small Haldane effect and some CO2 is probably bound to blood proteins. Carbonic anhydrase activity is located in the gill epithelium but is absent from the blood. Inhibition of carbonic anhydrase activity in vivo by injection of 50 mg/kg Diamox into the infrabranchial sinus causes a prolonged increase in blood Ps6, and the P6e, gradient across the gills. Both Me, and Mse, however, are maintained at normal rates during rest and severe exercise. The gill diffirsing capacity for CO2 is reduced
Journal of Comparative Physiology B, 1992
While on land and recirculating branchial water the Australian semaphore crab Heloecius cordiformis (Decapoda: Ocypodidae), a semi-terrestrial airbreathing mangrove crab, sequentially depresses and elevates its carapace in a regular pump-like manner. The functional role of these carapace movements in aerial oxygen consumption is investigated. Carapace immobilisation (reversible and non-injurious) did not appear to affect branchial water circulation. In "dry" crabs (branchial water removed) carapace immobilisafion had no effect on the rate of oxygen consumption (1702) , heart rate or whole-body lactate (WBL) levels. In "wet" crabs (with branchial water) carapace immobilisation caused ~'O 2 to drop by 38% from 81 to 46~1 O2-g-1 .h-I, heart rate to decline by 32%, from 2.5 to 1.7 Hz, and WBL levels to increase over 2.5-fold, from 0.27 to 0.67 mg 9 g-1, after 3 h of carapace immobilisation. The I~O2 of carapace-immobilised crabs with branchial water was similar to lung-occluded crabs with branchial water. Severe hypoxia induced physiological responses similar to those of carapace-immobilised crabs with branchial water. After 3 h of severe hypoxia, heart rate had declined by 80%, from 2.2 to 0.43 Hz, and the incidence of carapace pumping slowed by 85%, from 2.4 to 0.37 cycles 9 min-1. It is concluded that in the absence of carapace movements branchial water in some way interferes with lung ventilation. Under normal circumstances water circulation and lung ventilation are mutually exclusive processes (due to their singular dependence on the scaphognathites), yet in Heloecius these processes must be carried out simultaneously. Carapace movements may alleviate this conflict.
The morphology and vasculature of the lungs and gills of the soldier crab,Mictyris longicarpus
Journal of Morphology, 1987
The five gill pairs of Mictyris longicarpus have the lowest weight specific area reported for any crab. The cuticle of the gill lamellae is lined with epithelial cells which have structural features characteristic of iontransporting cells. Pillar cells are regularly distributed in the epithelium and serve to maintain separation of the two faces of the lamellae. The central hemolymph space is divided into two sheets by a fenestrated septum of connective tissue cells. The dorsal portion of the marginal canal of each lamella receives hemolymph from the afferent branchial vessel and distributes it to the lamella while the ventral portion of the canal collects hemolymph and returns it to the efferent branchial vessel.