Early ammonia release by a polychaete nereis virens and a crab carcinus maenas in diluted sea water

Salinity-induced changes in ammonia excretionas salinity drops from 34 %O to 14 %o, and is reduced to '1% during flood tide as the salinity returns to 34 %. The excretory response of C. crangon is influenced by at least 3 factors: direction of salinity change, salinity range over which the change occurred, and the velocity of this change. The effects of salinity fluctuations on the ammonia excretion rate of C. crangon are discussed in relation to the osmoregulatory mechanisms involved in the shrimp's adaptation to changing salinity. The excretory response of C. crangon to a winter tidal cycle is compared to that previously observed under summer conditions. The winter response is characterized by a much larger amplitude and a delay in adaptation. This last point is discussed in relation to the size of shrimp and the experimental temperature, both fitted to winter conditions. Total ammonia production over a 12 h tidal cycle was 167.53 k 3.47 pg N g 1 wet wt in shrimp undergoing tidal cycles, and 95.40 Â 9.83 pg N in shrimp maintained at a constant salinity (34 %o). Consequently, shrimp in estuarine conditions face a noticeable nitrogen loss compared to shrimp staying offshore. As opposed to summer conditions where the loss was negligible, some behavioural changes (migration, burrowing) are necessary for shrimp in order to survive winter estuarine conditions without damage.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Salinity-induced changes in ammonia excretion rate of the shrimp Crangon crangon over a winter tidal cycle

Regnault¹

1984

“…An increase in ammonia excretion with increasing temperature has been observed in the shore crab Carcinus nlaenas (Needham 1957). At low salinity (1O0A), an increase in ammonia-N excretion suggests that there is an increasing catabolism of amino acids, as was documented in Carcinus maenas by Haberfield et al (1975). The catabolism of amino acids is considered to be involved in osmotic regulation when animals are subjected to low salinity.…”

Section: --------------mentioning

confidence: 93%

Hemolymph ammonia and urea and nitrogenous excretions of Scylla serrata at different temperature and salinity levels

Chen¹,

Pg²

1996

Hemolymph ammonia and urea levels and nitrogenous excretions of Scylla serrala (Forskal) (202 * 18 g) were measured when the crabs were exposed to 9 different temperature and salinity regimes (15. 25. 35OC combined with 10, 25 and 40?L S). Hemolymph ammonia increased with a decrease in salinity, whereas hemolymph urea increased with a n increase in salinity. Nitrogenous excretion Increased with temperature. Excretion of ammonia-N, organic-N, nitrite-N, and nitrate-N and total nitrogen excretion (pg g-1 h I J increased with a decrease in salinity, whereas urea-N excret~o n increased w t h a n increase in salinity. At 25"C, ammonia-N excret~on accounted for 82 0, 79 2 and 56.2% of total nitrogen excreted by the crabs at 10, 25 and 40'!6, S, whereas urea-N excretion accounted for 4.3, 9.1 and 30 1 "t rcspectively It 1s concluded that the S. serrata at 40% S shlfts its excretory pattern from ammonlotr~lism to ureotelism.

“…The effects of extrinsic factors such as water temperature and salinity on ammonia excretion were documented for shore crab Carcinus maenas (Haberfield et al 1975), for Kuruma shrimp Penaeus japonicus (Spaargaren et al 1982), for tiger shrimp Penaeus monodon (Lei et al 1989) and for spot prawn Pandalus platyceros (Quarmby 1985). Increased ambient noise was also reported to affect ammonia excretion of sand shrimp Crangon crangon (Regnault & Lagardere 1983).…”

mentioning

confidence: 99%

Effects of ambient ammonia on ammonia-N and protein concentrations in hemolymph and ammonia-N excretion of Penaeus chinensis

Chen¹,

Nan²,

Cheng³

et al. 1993