Nano-sized diatoms are common members of phytoplankton communities and may play a significant role in export. Compared to micro-sized diatoms, little is known about their physiological responses, elemental, and biochemical composition of nano-sized diatoms in response to environmental conditions. To add to the small but growing database of knowledge of this group, Minidiscus trioculatus (CCMP 496) and Minutocellus polymorphus (CCMP 501) were acclimated and grown under a range of irradiances (15 to 480 μmol photons m^-2 s^-1 and temperatures (5 to 25 ⁰C) to determine their the growth rate, photophysiological response, and C:N:Si:P content under optimal and sub-optimal growth conditions. Both species exhibit: increases in C: N irradiance between 15 to 250 but a small decrease at 480 μmol photons m^-2 s^-1 (perhaps due to higher maintenance costs associated with photoinhibition), decreases in N:P with increasing temperature, and no clear trend in N:P with changes in growth rate due to irradiance or temperature. These results suggest that neither the growth rate hypothesis or the temperature compensation hypotheses apply to these small diatoms.

Primary Presenter: Ishari Nuwanthi Samarasinghe Gunasekara Liyanage, Dahousie University (nuwanthisamarasinghe89@gmail.com)

Authors:

Nuwanthi Samarasinghe, Dalhousie University  (nw914031@dal.ca)

Zoe Finkel, Dalhousie University  (zfinkel@dal.ca)

Yingyu Hu, Dalhousie University  (ruby.hu@dal.ca)