Gene expression during the formation of resting spores induced by nitrogen starvation in the marine diatom Chaetoceros socialis.

Background: Dormancy is widespread in both multicellular and unicellular organisms. Among diatoms, unicellular microalgae at the base of all aquatic food webs, several species produce dormant cells (spores or resting cells) that can withstand long periods of adverse environmental conditions.

Results: We present the first gene expression study during the process of spore formation induced by nitrogen depletion in the marine planktonic diatom Chaetoceros socialis.

'Boom-and-busted' dynamics of phytoplankton-virus interactions explain the paradox of the plankton.

Rapid virus proliferation can exert a powerful control on phytoplankton host populations, playing a significant role in marine biogeochemistry and ecology. We explore how marine lytic viruses impact phytoplankton succession, affecting host and nonhost populations. Using an in silico food web we conducted simulation experiments under a range of different abiotic and biotic conditions, exploring virus-host-grazer interactions and manipulating competition, allometry, motility and cyst cycles.

Virus-induced spore formation as a defense mechanism in marine diatoms.

Algal viruses are important contributors to carbon cycling, recycling nutrients and organic material through host lysis. Although viral infection has been described as a primary mechanism of phytoplankton mortality, little is known about host defense responses. We show that viral infection of the bloom-forming, planktonic diatom Chaetoceros socialis induces the mass formation of resting spores, a heavily silicified life cycle stage associated with carbon export due to rapid sinking.

Effects of elutriates from contaminated coastal sediments on different life cycle phases of planktonic diatoms.

We assessed the effects of elutriates from sediments collected at three stations in the polluted Bay of Bagnoli-Coroglio along the Campania coast (Tyrrhenian Sea, Italy) using three planktonic diatoms regularly occurring in the area, Pseudo-nitzschia multistriata, P. arenysensis and Chaetoceros socialis. Specifically, we tested the production of sexual stages in the heterothallic Pseudo-nitzschia species with the hypothesis that pollutants could impair sexual reproduction.