NITROGEN EXCRETION IN THE BIVALVE MOLLUSCS

이매패의 질소배설 2. 굴

The effects of temperature and salinity on tile rates of ammonia and amino nitrogen excretion, and oxygen consumption were measured for Crassostrea gigas. There was variability with temperature and salinity changes in both the rates of nitrogen excretion and the proportionality between ,ammonia and amino acids in the excreta, and also in the rates of oxygen consumption. Rates of nitrogen excretion and oxygen consumption were markedly decreased with increase in salinity, especially at high salinity-high temperature, whereas at low salinity-high temperature condition they were significantly increased. These changes are considered as the responses of physiological tolerances to the high temperature stress and the results of the metabolic temperature compensation at the low salinity-high temperature condition. Most of nitrogenous excretory products was ammonia, and large amounts of amino-nitrogen was excreted, and especially the rate of amino-nitrogen excretion was dominant at $32.5\%_{\circ}-22^{\circ}C$. The amounts of amino-nitrogen excreted by animals were decreased in the medium of high salinity and increased in the medium of low salinity through the experimental temperature. The atomic ratios of oxygen consumed to ammonia-nitrogen excreted (O: N ratio) was low at the low temperature $(15^{\circ}C)$, and was high at $22^{\circ}$ and $29^{\circ}C$ in the medium of 32.5 and $37.5\%_{\circ}$ but low in the low salinity $27.5\%_{\circ}$.

굴(Crassostrea gigas)의 질소배설과 산소소비에 미치는 수온 및 염분의 상호영향을 조사한 결과는 다음과 같다. 1. 굴은 수온과 염분변화에 따라 질소배설율과 배설암모니아 및 아미노산간의 배설비에 현저한 변동을 보였으며 산소소비량에도 역시 많은 변동을 보였다. 2. 질소배설율과 산소소비율은 염분이 증가함에 따라 특히 고염분일 때 고수온$(29^{\circ}C)$의 경우에 현저히 감소하였으나 저온분에서는 상당히 증가하였다. 이것은 생리적 내성의 고온단계와 저염분에 대한 포상작용에 기인한 결과라고 생가된다. 3. 암모니아를 주로 배설하였으나 상당한 량의 아미노-질소도 배설하였으며, 특히 상염분-온난온도대$(32.5\%_{\circ}-22^{\circ}C$에서는 아미노산의 배설량이 우세하였다. 그리고 어느 실험온도에서나 고염분에서 아미노-질소의 배설량은 감소하였고 저염분에서는 증가하였다. 4. 배설암모니아-질소에 대한 소비산소의 원자비 (O: N비)는 저온$(15^{\circ}C)$에서는 현저히 낮고 상온 및 고온($22^{\circ}$ 및 $29^{\circ}C$)에서는 높았다. 그러나 저온분의 경우 고온에서는 현저히 감소되었다.