Grazing-induced Changes in Cell Wall Silicification in a Marine Diatom

Pondaven, Philippe; Gallinari, Morgane; Chollet, Sophie; Bucciarelli, Eva; Sarthou, Géraldine; Schultes, Sabine; Jean, Fred

doi:10.1016/j.protis.2006.09.002

Cited by 106 publications

(75 citation statements)

References 35 publications

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“…Microzooplankton abundances were highest in the high temperature treatment by the end of the experiment. Increased diatom cell wall silicification in response to grazing pressure has been documented in the laboratory (Pondaven et al, 2007), but not to our knowledge in natural plankton assemblages.…”

Section: Discussionmentioning

confidence: 77%

Synergistic effects of iron and temperature on Antarctic phytoplankton and microzooplankton assemblages

et al. 2009

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Abstract. Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM) and increased temperature (+4 • C) on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total phytoplankton abundance, phytoplankton and microzooplankton community composition, as well as photosynthetic parameters and nutrient drawdown. Unexpectedly, increased iron had a consistently negative impact on microzooplankton abundance, most likely a secondary response to changes in phytoplankton community composition. When iron and temperature were increased in concert, the resulting interactive effects were greatly magnified. This synergy between iron and temperature increases would not have been predictable by examining the effects of each variable individually. Our results suggest the possibility that if iron availability increases under future climate regimes, the impacts of predicted temperature increases on plankton assemblages in polar regions could be significantly enhanced. Such synergistic and antagonistic interactions between individual climate change variables highlight the importance of multivariate studies for marine global change experiments.

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Section: Discussionmentioning

confidence: 77%

Synergistic effects of iron and temperature on Antarctic phytoplankton and microzooplankton assemblages

et al. 2009

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“…This may be achieved by producing grazerdeterring compounds in dinoflagellates (Selander et al 2006) or by escape behavior in ciliates and flagellates (Jakobsen 2002). Structural changes can also be a defense mechanism; Pondaven and colleagues (Pondaven et al 2007) found that the marine diatom Thalassiosira weissflogii increased the cell wall silicification in response to cues from grazing copepods. We hypothesize that a shift in chain length in order to fall outside the optimal prey size range of the dominant grazers is another such strategy successfully employed by S. marinoi.…”

Section: Discussionmentioning

confidence: 99%

Grazer‐induced chain length plasticity reduces grazing risk in a marine diatom

Bergkvist

Thor

Jakobsen³

et al. 2012

Limnology & Oceanography

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We show that Skeletonema marinoi suppresses chain formation in response to copepod cues. The presence of three different copepod species (Acartia tonsa, Centropages hamatus, or Temora longicornis) significantly reduced chain length. Furthermore, chain length was significantly reduced when S. marinoi was exposed to chemical cues from caged A. tonsa without physical contact with the responding cells. The reductions in chain length significantly reduced copepod grazing; grazing rates on chains (four cells or more) were several times higher compared to that of single cells. This suggests that chain length plasticity is a means for S. marinoi to reduce copepod grazing. In contrast, chain length was not suppressed in cultures exposed to the microzooplankton grazer Gyrodinium dominans. Size-selective predation may have played a key role in the evolution of chain formation and chain length plasticity in diatoms.

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“…Yet, additional evolutionary selective pressures on the morphology of the siliceous diatom frustule have been identified, including changes in growth-limiting nutrients other than Si (Marchetti and Cassar, 2009), CO 2 (Milligan and Morel, 2002), and predation (Pondaven et al, 2007) have shaped the morphology of the frustule over geologic time (Finkel and Kotrc, 2010). In addition, Si transporter (SITs, SIT-Ls and Lsi2-like) genes are found in many eukaryotes that are not major biosilicifiers today (Marron et al, 2016), yet in some organisms (e.g., calcareous haptophytes) Si is required in trace amounts (Durak et al, 2016).…”

Section: Biosilicification Is Not the Only Factormentioning

confidence: 99%

Biosilicification Drives a Decline of Dissolved Si in the Oceans through Geologic Time

et al. 2017

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Biosilicification has driven variation in the global Si cycle over geologic time. The evolution of different eukaryotic lineages that convert dissolved Si (DSi) into mineralized structures (higher plants, siliceous sponges, radiolarians, and diatoms) has driven a secular decrease in DSi in the global ocean leading to the low DSi concentrations seen today. Recent studies, however, have questioned the timing previously proposed for the DSi decreases and the concentration changes through deep time, which would have major implications for the cycling of carbon and other key nutrients in the ocean. Here, we combine relevant genomic data with geological data and present new hypotheses regarding the impact of the evolution of biosilicifying organisms on the DSi inventory of the oceans throughout deep time. Although there is no fossil evidence for true silica biomineralization until the late Precambrian, the timing of the evolution of silica transporter genes suggests that bacterial silicon-related metabolism has been present in the oceans since the Archean with eukaryotic silicon metabolism already occurring in the Neoproterozoic. We hypothesize that biological processes have influenced oceanic DSi concentrations since the beginning of oxygenic photosynthesis.

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Grazing-induced Changes in Cell Wall Silicification in a Marine Diatom

Cited by 106 publications

References 35 publications

Synergistic effects of iron and temperature on Antarctic phytoplankton and microzooplankton assemblages

Synergistic effects of iron and temperature on Antarctic phytoplankton and microzooplankton assemblages

Grazer‐induced chain length plasticity reduces grazing risk in a marine diatom

Biosilicification Drives a Decline of Dissolved Si in the Oceans through Geologic Time

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