Laboratorary Experiments with a Mixotrophic Chrysophyte and Obligately Phagotrophic and Photographic Competitors

Rothhaupt, Karl O.

doi:10.2307/2265496

Cited by 170 publications

(169 citation statements)

References 19 publications

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“…Second, deepening of thermoclines increased the heat content of the lakes during the 2000s, further benefiting smaller species that are more responsive to warming (7). Finally, elevated DOC and lower nutrient concentrations favored mixotrophic chrysophytes over obligate photoautotrophic algae because the former can acquire essential nutrients via the consumption of DOC (36).…”

Section: Resultsmentioning

confidence: 99%

Recent climate extremes alter alpine lake ecosystems

Parker

Vinebrooke

Schindler

2008

Proc. Natl. Acad. Sci. U.S.A.

144

100

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Here, we show that alpine lake ecosystems are responsive to interannual variation in climate, based on long-term limnological and meteorological data from the Canadian Rockies. In the 2000s, in years with colder winter temperatures, higher winter snowfall, later snowmelt, shorter ice-free seasons, and dryer summers, relative to the 1990s, alpine lakes became clearer, warmer, and mixed to deeper depths. Further, lakes became more dilute and nutrient-poor, the latter leading to significant declines in total phytoplankton biomass. However, increased concentrations of dissolved organic carbon in lake water stimulated the appearance of small mixotrophic algal species, partially offsetting the decline in autotrophic phytoplankton biomass and increasing algal species richness. The climate regime in the 2000s altered the physical, chemical, and biological character and the function of high-elevation aquatic ecosystems. Forecasts of increased climatic variability in the future pose serious ramifications for both the biodiversity and ecosystem function of high-elevation lakes.function ͉ biodiversity ͉ plankton ͉ global change

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Section: Resultsmentioning

confidence: 99%

Recent climate extremes alter alpine lake ecosystems

Parker

Vinebrooke

Schindler

2008

Proc. Natl. Acad. Sci. U.S.A.

144

100

View full text Add to dashboard Cite

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“…The mixotrophic strategy is expected to be successful when resources (for example, dissolved nutrients) limit strictly autotrophic growth (Rothhaupt, 1996;Flö der et al, 2006). Considering that assimilation of nutrients in particulate form is energetically more costly than absorbing them in dissolved inorganic form (Raven, 1997) and if phagotrophy is a way to supplement nutrients, then an inverse relationship should be expected between a given limiting nutrient and the phagotrophic activity of the mixotrophic community.…”

Section: Factors Controlling Ingestion Rates In the Dominant Mixotrophsmentioning

confidence: 99%

“…The mixotrophic mode of nutrition is considered to be particularly beneficial when inorganic nutrients are limiting (Nygaard and Tobiesen, 1993;Rothhaupt, 1996;Flö der et al, 2006). It has been demonstrated that mixotrophic algae, in particular those o5 mm in size, are major grazers of picoplankton in oligotrophic marine systems, being regularly responsible for 450% of the total bacterivory (Unrein et al, 2007;Zubkov and Tarran, 2008;Hartmann et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Mixotrophic haptophytes are key bacterial grazers in oligotrophic coastal waters

et al. 2013

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Grazing rate estimates indicate that approximately half of the bacterivory in oligotrophic oceans is due to mixotrophic flagellates (MFs). However, most estimations have considered algae as a single group. Here we aimed at opening the black-box of the phytoflagellates (PFs) o20 lm. Haptophytes, chlorophytes, cryptophytes and pigmented dinoflagellates were identified using fluorescent in situ hybridization or by standard 4 0 ,6-diamidino-2-phenylindole staining. Their fluctuations in abundance, cell size, biomass and bacterivory rates were measured through an annual cycle in an oligotrophic coastal system. On average, we were able to assign to these groups: 37% of the total pico-PFs and 65% of the nano-PFs composition. Chlorophytes were mostly picoplanktonic and they never ingested fluorescently labeled bacteria. About 50% of the PF o20 lm biomass was represented by mixotrophic algae. Pigmented dinoflagellates were the least abundant group with little impact on bacterioplankton. Cryptophytes were quantitatively important during the coldest periods and explained about 4% of total bacterivory. Haptophytes were the most important mixotrophic group: (i) they were mostly represented by cells 3-5 lm in size present year-round; (ii) cell-specific grazing rates were comparable to those of other bacterivorous non-photosynthetic organisms, regardless of the in situ nutrient availability conditions; (iii) these organisms could acquire a significant portion of their carbon by ingesting bacteria; and (iv) haptophytes explained on average 40% of the bacterivory exerted by MFs and were responsible for 9-27% of total bacterivory at this site. Our results, when considered alongside the widespread distribution of haptophytes in the ocean, indicate that they have a key role as bacterivores in marine ecosystems.

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“…An excellent start has been made by Rothhaupt (1996b) in his laboratory experiments involving a mixotrophic chrysophyte and obligately phagotrophic and phototrophic competitors.…”

Section: Evolutionary Costs That May Offset the Benefits Of Phagotropmentioning

confidence: 99%