Sargent et al. (1977) [21] hypothesised that lipids were synthesise de novo using the carbon skeleton of amino structure of the amino acids by removing the nitrate from these structures. These amino-structures would then be used to synthesise fatty alcohol that would then results in carbohydrates and wax esters. Then an individual accumulating lipids should excrete a higher amount of nitrogen than carbon. This has been found by Båmstedt et Tande (1985) [17] who studied in mid-spring an Arctic copepod (Calanus glacialis) known to over-winter for many months, that exhibited a difference of nitrogen excretion 2.6 to 8.9 times higher than the carbon excretion. Once in diapause, they will reduce their metabolism and move into a dormant phase, staying immobile, without reactions to stimulus and usually torpid Auel et al. (2003) [8].  In that state, the nitrogen excretion seems to be extremely reduced or too low to be measured in situ [Tande (1982) [9].