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

Abstract

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.

Effects of Acute Salinity Stress on Oxygen Consumption and Ammonia Excretion Rates of the Marine Shrimp Metapenaeus Monoceros

“…The effect of a salinity increase upon nitrogen excretion, however, appears to be more complex as inconsistent responses have been reported (Regnault, 1984). In the present study, exposure of low saline acclimated shrimps to high-saline media resulted in a significant decrease in ammonia excretion rate.…”

“…In P. chinensis, Chen and Nan (1993) reported an increase in O:N ratio with an increase in salinity of the environment. In Crangon crangon Linnaeus, an O:N ratio of 27 was reported to be reflective of mostly lipid catabolism (Regnault, 1984). Upon continued stress, the O:N ratio in the above species declined to 10, indicating that only proteins were catabolised.…”

“…Similarly, the effect of salinity on the rate of crustacean ammonia excretion has extensively been studied (Regnault, 1984;Taylor et al, 1987;Diwan and Baskaran, 1992;Chen and Chia, 1996). Further, researchers are also looking into the influence of environmental factors, including salinity, on the relationship between oxygen consumed and excreted nitrogen (atomic O:N ratio), as it can provide information on the changes in energy substrate utilization under various environmental regimes (Mayzaud and Conover, 1988).…”

Oxygen consumption, ammonia excretion and osmoregulation of callinectes similis Juveniles (Crustacea: Portunidae) exposed to fluctuating salinities

“…Al disminuir la salinidad de 35 a 24o/oo, la respuesta obtenida para C. similis fue un incremento en la tasa de excreción de amonio, resultado que ya ha sido reportado para varias especies de crustáceos eurihalinos como Ca&rus maenas (Needham, 1957) Callinectes sapidus (Mangum et al, 1976;Pressley et al, 1981) Cmngon crangon (Regnault, 1984) y 1981) Cmngon crungon (Regnault, 1984) and Palaemon elegans (Taylor et al, 1987). When salinity decreases, the increase in ammonia excretion can be attributed to the active uptake of sodium required by the animals to compensate for the loss in hypotonic media, as mentioned by Mangum et al (1976) and Pressley et al (1981).…”

Brown shrimp abundance in northwest European coastal waters from 1970 to 2010 and potential causes for contrasting trends

“…Salinity tolerance is temperature and age dependent, but generally brown shrimp are found at salinities between 7 and 40 PSU (McLusky et al 1982). In spring tide periods, shrimp are exposed to tidal salinity fluctuations ranging from 25 to 25 PSU in summer and from 14 to 34 PSU in winter (Regnault 1984). Egg development can occur at salinities >15 PSU, (Broekema 1942) and temperatures between 6 and 21°C (Wear 1974).…”