Feeding by heterotrophic flagellates on marine archaea

Lee, Moo Joon; Yoo, Yeong Du; Seong, Kyeong Ah; Yeon, Yang Hee; Kang, Yi Gu; Rhee, Sung‐Keun; Kim, Jong-Geol; Lee, Gyu Gil; Lee, Sung Ki; Shin, Woongghi; Ryu, Jong Seong

doi:10.1016/j.rsma.2022.102665

Cited by 2 publications

(2 citation statements)

References 74 publications

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“…Although various factors (e.g., substrate concentrations, irradiance) that affect ammonia oxidation have been documented and parameterized in models (Wan et al, 2021;Ward, 2008Ward, , 2011Xu et al, 2018;Zakem et al, 2018), the impact of grazing on AO and the rate of ammonia oxidation remain understudied. Previous studies have shown that grazers in laboratory cultures and lakes have the ability to directly graze ammoniaoxidizing bacteria (AOB) (Neubacher et al, 2008) and ammonia-oxidizing archaea (AOA) (Lee et al, 2022;Peter et al, 1997). Archaea have also been shown to be an important and nutritious food source for the growth of zooplankton (Thurber et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Top‐Down Control of Ammonia Oxidizers by Grazing in the North Pacific

Ni,

Xu,

et al. 2024

Geophysical Research Letters

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The impact of grazing pressure on ammonia oxidizers (AO) has never been quantified in the field. Here we develop a new method to quantify the grazing rates on AO in aquatic systems. We introduce 15NH4+ tracer into the traditional dilution experiments to measure AO's apparent growth rates by using the end‐product of 15NH4+ oxidation, that is, 15NOx−. Field studies in the North Pacific revealed that 15NOx− in the end‐product was sensitive enough to detect AO's grazing rates. Experiments from the lower euphotic zone showed NH4+ replete growth rates of 0.40 d−1 and 0.77 d−1 of AO and in situ grazing rates on AO of 0.41 d−1 and 0.45 d−1, respectively, indicating a strong top‐down control by grazing on AO. Compiled data show a vertical decoupling between ammonia oxidation rates and AO abundance within the euphotic zone, indicating that strong grazing may have affected the distribution of AO in the global ocean.

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Section: Introductionmentioning

confidence: 99%

Top‐Down Control of Ammonia Oxidizers by Grazing in the North Pacific

Ni,

Xu,

et al. 2024

Geophysical Research Letters

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“…Protists, as microscopic eukaryotes, are an important but generally ignored component of soil food webs. Protists are of major importance for ecosystem stability and providers of ecosystem services, such as nutrient cycling, population control and carbon sequestration ( Geisen, 2016 ; Lee et al, 2022 ). Furthermore, protists are useful in applied research as bioindicators of soil quality ( Geisen et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Fertilization drives distinct biotic and abiotic factors in regulating functional groups of protists in a 5-year fertilization system

Zhang

et al. 2022

Front. Microbiol.

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IntroductionProtists play an important role in nutrient cycling, microbiome stability and soil fertility maintenance. However, the driving force of protistan functional groups remains poorly understood in agricultural ecosystems.MethodsWe investigated the impacts of fertilization regimes on the diversity, composition and functional groups of protists and further disentangled the effects of multiple factors shaping the community composition of functional groups in a 5-year fertilization regime (CK, no fertilization; M, organic fertilization; MNPK, combined inorganic and organic fertilization; NPK, inorganic fertilization).ResultsFertilization significantly changed the community composition of protists rather than diversity. The MNPK treatment significantly increased the relative abundance of phototrophs and decreased that of the parasites and consumers. Partial least squares path modeling indicated that fertilization indirectly regulated protistan consumers via changes in the P content, which affected the composition of consumers mainly by regulating fungal community composition. Soil moisture (SM) and available phosphorus (AP) were identified as the top predictors for the composition of parasites, and the composition of phototrophs was mainly affected by SM, indicating that parasites and phototrophs were more sensitive to abiotic factors in the fertilization system.DiscussionTaken together, our findings highlight that fertilization significantly affects the composition of functional groups of protists and their biotic or abiotic regulatory processes, which have implications for the potential changes in their ecosystem functions for soil management systems.

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Feeding by heterotrophic flagellates on marine archaea

Cited by 2 publications

References 74 publications

Top‐Down Control of Ammonia Oxidizers by Grazing in the North Pacific

Top‐Down Control of Ammonia Oxidizers by Grazing in the North Pacific

Fertilization drives distinct biotic and abiotic factors in regulating functional groups of protists in a 5-year fertilization system

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