Nitrogen excretion by copepods and its effect on ammonia‐oxidizing communities from a coastal upwelling zone

Valdés, Valentina; Fernández, Camila; Molina, Verónica; Escribano, Rubén

doi:10.1002/lno.10629

Cited by 18 publications

(14 citation statements)

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“…In the late-summer experiment, NH accumulation in the treatment with copepods fed with the 20-150-µm size-fraction diet suggested that nitrification processes occurred during the incubations. This was expected considering the previous findings of a tight coupling between excretion and ammonia oxidation (Molina et al, 2005(Molina et al, , 2012 and the functional microbial groups involved (Valdés et al, 2017). During the late summer experiment, the treatment with copepods fed with the <20-µm size-fraction diet was characterized by a high consumption of nitrogen compounds between the initial period and 4 h of incubation, with an NH In addition, the DOM quality, evaluated by changes in the DON:DOP ratio (Supplementary Figure 10), could influence the microbial response to copepod excretion product enrichments.…”

Section: Potential Fate Of Dissolved Organic and Inorganic Compounds supporting

confidence: 60%

Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

et al. 2017

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Copepods are important suppliers of bioreactive compounds for marine bacteria through fecal pellet production, sloppy feeding, and the excretion of dissolved compounds. However, the interaction between copepods and bacteria in the marine environment is poorly understood. We determined the nitrogen and phosphorus compounds excreted by copepods fed with two natural size-fractionated diets (<20-and 20-150-µm) in the upwelling zone of central/southern Chile in late summer and spring. We then assessed the biogeochemical response of the bacterial community and its structure, in terms of total and active cells, to enrichment by copepod-excreted dissolved compounds. Results revealed that copepods actively excreted nitrogen and phosphorus compounds, mainly in the form of ammonium and dissolved organic phosphorus (DOP), reaching excretion rates of 2.6 and 0.05 µmol L −1 h −1 , respectively. In both periods, the maximum excretion rates were associated with the 20-150-µm size fraction, but particularly during spring, when a higher organic matter quality was observed in excretion products compared to late summer. There were higher excretion rates of dissolved free amino acids (DFAAs) from copepods fed with the <20-µm size fraction, mainly histidine (HIS) in late summer and glutamic acid (GLU) in spring. A shift in the composition of the active bacterial community was observed between periods and treatments, which was associated with the response of the common seawater surface phyla Proteobacteria and Bacteroidetes. The specific bacterial activity (16S rRNA:rDNA) suggested a different response to the two size-fractionated diets. In late summer, Betaproteobacteria and Bacteroidetes were stimulated by the treatment enriched with excretion products derived from the 20-150-µm and <20-µm size fractions, respectively. In spring, Alphaproteobacteria were active in the treatment enriched with the excretion products of copepods fed with the <20-µm size fraction, whereas they were inhibited in the treatment enriched with excretion products in the 20-150-µm size fraction. Our findings indicate that different Valdés et al. Copepod Excretion and Bacterial Community Structure copepod diets can have a significant impact on the quantity and quality of their excretion compounds, which can subsequently generate shifts in the active bacterial composition. The bacterial response is probably associated with common-opportunistic sea surface microbes that are adapted to rapidly reacting to environmental offers.

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Section: Potential Fate Of Dissolved Organic and Inorganic Compounds supporting

confidence: 60%

Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

et al. 2017

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“…Among other organic C‐substrates, taurine stimulates growth in Nitrosocosmicus exaquare , thereby accelerating its ammonium‐oxidizing activity (Sauder et al 2017). Valdés et al (2018 b ) showed that ammonia oxidizing archaea are highly active in coastal waters off central Chile in winter in response to DON released by copepods, outcompeting ammonia‐oxidizing bacteria at ammonia concentrations close to the detection limit.…”

Section: Discussionmentioning

confidence: 99%

“…Hence, although crustacean zooplankton are synthesizing taurine, the elevated taurine and DFAA release rates during the fall–winter period might also be attributed to taurine‐ and DFAA‐enriched diet and/or harmful phytoplankton. Additionally, the quality, quantity, composition, and the size of the available diet can strongly influence the release rates of DOM compounds by copepods (Frangoulis et al 2004; Valdés et al 2017) and thus, the organic C, N, and S available to heterotrophic prokaryotes (Valdés et al 2018 a , b ). The diversity of copepod species was higher in the fall–winter period, especially of small‐sized species, than in the spring–summer period (Supporting Information Table S1).…”

Section: Discussionmentioning

confidence: 99%

Mesozooplankton taurine production and prokaryotic uptake in the northern Adriatic Sea

Corte

Amano

Paliaga

et al. 2020

Limnology & Oceanography

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Dissolved free taurine, an important osmolyte in phytoplankton and metazoans, has been shown to be a significant carbon and energy source for prokaryotes in the North Atlantic throughout the water column. However, the extent of the coupling between taurine production and consumption over a seasonal cycle has not been examined yet. We determined taurine production by abundant crustacean zooplankton and its role as a carbon and energy source for several prokaryotic taxa in the northern Adriatic Sea over a seasonal cycle. Taurine concentrations were generally in the low nanomolar range, reaching a maximum of 22 nmol L −1 in fall during a Pseudonitzschia bloom and coinciding with the highest zooplankton taurine release rates. Taurine accounted for up to 5% of the carbon, 11% of the nitrogen, and up to 71% of the sulfur requirements of heterotrophic prokaryotes. Members of the Roseobacter clade, Alteromonas, Thaumarchaeota, and Euryarchaeota exhibited higher cell-specific taurine assimilation rates than SAR11 cells. However, cell-specific taurine and leucine assimilation were highly variable in all taxa, suggesting species and/or ecotype specific utilization patterns of taurine and dissolved free amino acids. Copepods were able to cover the bulk taurine requirements of the prokaryotic communities in fall and winter and partly in the spring-summer period. Overall, our study emphasizes the significance of taurine as a carbon and energy source for the prokaryotic community in the northern Adriatic Sea and the importance of crustacean zooplankton as a significant source of taurine and other organic compounds for the heterotrophic prokaryotic community.

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“…The nitrogen regime is mainly affected by human activities, including domestic sources, agricultural sources, livestock farming, and aquaculture sources. Except for the terrestrial sources, there are autogenous nitrogen sources, such as ammonium excretion by phytoplankton and zooplankton, and urea excretion by fish, which might affect the algal growth and species composition by the microbial loop (Arzul et al, 2001; Coello‐Camba et al, 2017; Glibert et al, 2016; Valdes et al, 2018). Generally, diatoms prefer nitrate as a source of nitrogen, with higher affinity coefficients than ammonium and urea in the culture experiment ( p < 0.05), whereas dinoflagellates prefer ammonium or urea (Li et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Effect of Ambient Nitrogen on the Growth of Phytoplankton in the Bohai Sea: Kinetics and Parameters

et al. 2020

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Changes in nitrogen forms and levels affect biogeochemical processes, but little is known about the quantitative effect of ambient nitrogen on phytoplankton growth in biogeochemical kinetics. Based on a new experimental data analysis method, we investigated the phytoplankton growth and nitrogen uptake processes of typical phytoplankton subjected to different nitrogen forms in the Bohai Sea. We employed a nonlinear differential model to fit the kinetic processes of phytoplankton growth, death, and nutrient uptake considering multiple equations and parameters. The maximum nitrogen uptake rate (k up), half-saturation coefficient (k s), and maximum phytoplankton growth rate (k G) were obtained based on the multivariate nonlinear differential mothed. The k up and k s were related with k G for different ambient nitrogen forms (urea, ammonium, and nitrate) in the N sufficiency experiment group I (SGI) treatment, showing that phytoplankton grew faster in the presence of ammonium and nitrate than in the presence of urea, owing to quicker nitrogen uptake rate. The k up , k s , and k G in the N-Starvation experiment group II (SGII) treatment were lower than that in the SGI treatment, indicating higher nutrient affinity of phytoplankton at lower nitrogen concentrations. Hence, we can infer that eutrophic algae such as Nitzschia closterium may easily become the dominant species in the SGI treatment with abundant nitrogen supply and high k G , k up , and k s. In contrast, oligotrophic algae such as Leptocylindrus danicus and Asterionellopsis glacialis may easily become the dominant species in the SGI or SGII treatments with an insufficient supply of ambient nitrogen and low k G , k up , and k s. Plain Language Summary The ecosystem is vulnerable in coastal waters, suffering by human activities associated with anthropogenic nutrients, such as harmful algae bloom. The forms and levels of nutrients affect phytoplankton growth, while little is known about the biogeochemical kinetics. We investigated the phytoplankton growth and nitrogen uptake kinetics of typical phytoplankton subjected to different nitrogen forms (e.g., urea, ammonium, and nitrate) in the Bohai Sea. We proposed a multivariate nonlinear differential fitting method to analyze ecological experimental data, considering multiple kinetic equations and parameters of phytoplankton growth, death, and nutrient uptake. Based on the in situ batch culture experiment, the phytoplankton grew faster in ambient ammonium and nitrate than in ambient urea in the N sufficiency experiment group conditions, whereas, they grew and acquired nutrient significantly lower in the N starvation experiment group conditions. The phytoplankton domain community was different in different ambient nitrogen forms and levels, where eutrophic algae such as Nitzschia closterium might easily become the dominant species in the N sufficiency treatment with abundant nitrogen supply, whereas, oligotrophic algae such as Leptocylindrus danicus and Asterionellopsis glacialis might easily become the dominant spe...

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Nitrogen excretion by copepods and its effect on ammonia‐oxidizing communities from a coastal upwelling zone

Cited by 18 publications

References 86 publications

Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

Mesozooplankton taurine production and prokaryotic uptake in the northern Adriatic Sea

Effect of Ambient Nitrogen on the Growth of Phytoplankton in the Bohai Sea: Kinetics and Parameters

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