Status: this preprint was under review for the journal BG but the revision was not accepted.
Interactive effects of and light on growth rates and RUBISCO content of small and large centric diatoms
G. Liand D. A. Campbell
Abstract. Among marine phytoplankton groups, diatoms span the widest range of cell size, with resulting effects upon their nitrogen uptake, photosynthesis and growth responses to light. We grew two strains of marine centric diatoms, the small Thalassiosira pseudonana and the larger T. punctigera in high and low nitrogen media, across a range of growth light levels. Nitrogen and total proteins per cell decreased with increasing growth light in both species when grown under low nitrogen media. Surprisingly, low nitrogen increased the cellular allocation to RUBISCO and the rate of electron transport away from Photosystem II for the smaller diatom under low growth light, and for the larger diatom across the range of growth lights. Low nitrogen decreased the growth rate of the smaller diatom, particularly under higher light, but stimulated the growth rate of the larger diatom. Our results show that the high nitrogen in common growth media favours the growth rate of a small diatom but inhibits growth of a larger species.
Received: 24 Sep 2015 – Discussion started: 16 Oct 2015
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Marine photosynthetic diatoms span a range of cellular sizes, with important implications for carbon cycling. Nitrogen is increasing rapidly in coastal areas. We grew small and large marine centric diatoms and found that under low nitrogen media both strains conserved their cellular allocation of nitrogen to their photosynthetic system. The large diatom grew faster under low nitrogen, while the small diatom could exploit high levels of nitrogen to grow faster.
Marine photosynthetic diatoms span a range of cellular sizes, with important implications for...
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