Effects of Temperature and Salinity on the Growth and the Optimum Nitrogen to Phosphorus Ratio for the Culture of Diatoma tenue Isolated from a Temporary Arctic Pond in Svalbard, Norway

ABSTRACT

We investigated the effects of temperature and salinity on the growth of Diatoma tenue isolated from a temporary arctic pond in a high-latitude region of Svalbard, Norway. We also examined the optimum nitrogen to phosphorus (N:P) ratio of the culture media. The highest growth rate (0.38 day⁻¹) of D. tenue was achieved at 15°C, while growth was completely inhibited above 20°C. D. tenue could not grow when cultured at above 5%_o salinity. The final cell density of D. tenue was increased with an increasing phosphate concentration in the culture media from 0 to 5 μmol P L⁻¹. The final cell density became stable at above 5 μmol P L⁻¹. The N:P molar ratio of the media containing 5 μmol P L⁻¹ was 34.8. These results show that D. tenue growth is limited by phosphorus at N:P ratios greater than 34.8, with a nitrogen limitation below 34.8. This finding indicates that this alga has a higher optimum N:P ratio than the Redfield ratio of 16.