scholarly journals Enhanced microbial nitrogen transformations in association with macrobiota from the rocky intertidal

2019 ◽  
Vol 16 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Catherine A. Pfister ◽  
Mark A. Altabet
Keyword(s):  
Microbial Activity ◽  
Inorganic Nitrogen ◽  
Phosphorus Uptake ◽  
Red Alga ◽  
Time Of Day ◽  
Ammonium Oxidation ◽  
Nitrogen Transformations ◽  
Marine Animals ◽  
Microbial Nitrogen ◽  
Direct Association

Abstract. Microbial nitrogen processing in direct association with marine animals and seaweeds is poorly understood. Microbes can both attach to the surfaces of macrobiota and make use of their excreted nitrogen and dissolved organic carbon (DOC). We tested the role of an intertidal mussel (Mytilus californianus) and red alga (Prionitis sternbergii), as well as inert substrates for microbial activity using enclosed chambers with seawater labeled with 15N-enriched ammonium and nitrate. Chambers with only seawater from the same environment served as a control. We found that 3.21 nmol of ammonium per gram of dry mass of mussel, on average, was oxidized per hour, while 1.60 nmol of nitrate was reduced per hour. Prionitis was associated with the oxidation of 1.50 nmol of ammonium per gram of wet mass per hour, while 1.56 nmol of nitrate was reduced per hour. Inert substrates produced relatively little change compared to seawater alone. Extrapolating to a square meter of shoreline, microbial activity associated with mussels could oxidize 2.5 mmol of ammonium and reduce per 1.2 mmol of nitrate per day. A square meter of seaweed could oxidize 0.13 mmol ammonium per day and reduce the same amount of nitrate. Seawater collected proximal to the shore versus 2–5 km offshore showed no difference in ammonium oxidation or nitrate reduction. Microbial nitrogen metabolism associated with mussels was not influenced by the time of day. When we experimentally added DOC (glucose) as a carbon source to chambers with the red alga and inert substrates, no change in nitrification rates was observed. Added DOC did increase dissolved inorganic nitrogen (DIN) and phosphorus uptake, indicating that DOC addition stimulated heterotrophic microbial activity, and suggests potential competition for DIN between heterotrophic and chemolithotrophic microbes and their seaweed hosts. Our results demonstrate that microbes in direct association with coastal animals and seaweeds greatly enhance nitrogen processing and likely provide a template for a diversity of ecological interactions.

scholarly journals Enhanced microbial nitrogen transformations in association with intertidal macrobiota

2018 ◽  
Author(s):  
Catherine A. Pfister ◽  
Mark A. Altabet
Keyword(s):  
Microbial Activity ◽  
Nitrate Reduction ◽  
Phosphorus Uptake ◽  
Ammonium Oxidation ◽  
Nitrogen Transformations ◽  
Marine Animals ◽  
Microbial Nitrogen ◽  
Direct Association ◽  
Inert Substrate

Abstract. Microbial nitrogen processing in direct association with marine animals and seaweeds is poorly understood. Macrobiota supply a substrate for microbes to reside, and a source of excreted nitrogen and dissolved organic carbon (DOC). We tested the role of a mussel (Mytilus californianus), a red alga (Prionitis sternbergii) and an inert substrate for microbial activity using enclosed chambers and enriched ammonium and nitrate. Chambers with seawater from the same environment served as a control. We found that mussels and Prionitis elevated ammonium oxidation and nitrate reduction two orders of magnitude over that of seawater, while the effect of simply an inert substrate had relatively little effect. Extrapolating to a square meter of shoreline, microbial activity associated with mussels could oxidize 2.5 mmol of ammonium and reduce per 1.2 mmol of nitrate per day. A square meter of seaweed could produce even higher rates, at 135.2 and 320.5 mmol per day for nitrification and nitrate reduction, respectively. Seawater collected from the shore versus 2–5 km offshore showed no difference in ammonium oxidation or nitrate reduction. Microbial nitrogen metabolism associated with mussels did not change whether we measured it at night or during the day. When we experimentally added DOC (glucose) as a carbon source, there was no change to nitrification rates. Added DOC did increase DIN and phosphorus uptake, indicating that elevating the concentration of DOC stimulated heterotrophic microbial activity, and suggests potential competition for DIN between heterotrophic and chemolithotrophic microbes and their seaweed hosts. Our results indicate that microbes in direct association with coastal animals and seaweeds greatly enhance nitrogen processing, and likely provide a template for a diversity of ecological interactions.

scholarly journals Nitrification–denitrification in waste stabilisation ponds: a mechanism for permanent nitrogen removal in maturation ponds

2010 ◽  
Vol 61 (5) ◽  
pp. 1137-1146 ◽  
Author(s):  
M. A. Camargo Valero ◽  
L. F. Read ◽  
D. D. Mara ◽  
R. J. Newton ◽  
T. P. Curtis ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Inorganic Nitrogen ◽  
Isotope Analysis ◽  
Pilot Scale ◽  
Intermediate Step ◽  
Nitrogen Transformations ◽  
Waste Stabilisation Ponds ◽  
Molecular Microbiology ◽  
Denitrification Process ◽  
Ammonia Oxidising Bacteria

A pilot-scale primary maturation pond was spiked with 15N-labelled ammonia (15NH4Cl) and 15N-labelled nitrite (Na15NO2), in order to improve current understanding of the dynamics of inorganic nitrogen transformations and removal in WSP systems. Stable isotope analysis of δ15N showed that nitrification could be considered as an intermediate step in WSP, which is masked by simultaneous denitrification, under conditions of low algal activity. Molecular microbiology analysis showed that denitrification can be considered a feasible mechanism for permanent nitrogen removal in WSP, which may be supported either by ammonia-oxidising bacteria (AOB) or by methanotrophs, in addition to nitrite-oxidising bacteria (NOB). However, the relative supremacy of the denitrification process over other nitrogen removal mechanisms (e.g., biological uptake) depends upon phytoplanktonic activity.

scholarly journals Biogeochemical Regimes in Shallow Aquifers Reflect the Metabolic Coupling of the Elements Nitrogen, Sulfur, and Carbon

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Carl-Eric Wegner ◽  
Michael Gaspar ◽  
Patricia Geesink ◽  
Martina Herrmann ◽  
Manja Marz ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Groundwater Flow ◽  
Inorganic Nitrogen ◽  
Sulfur Metabolism ◽  
Ammonium Oxidation ◽  
Metabolic Potential ◽  
Differentiation Potential ◽  
Near Surface ◽  
Monitoring Wells

ABSTRACTNear-surface groundwaters are prone to receive (in)organic matter input from their recharge areas and are known to harbor autotrophic microbial communities linked to nitrogen and sulfur metabolism. Here, we use multi-omic profiling to gain holistic insights into the turnover of inorganic nitrogen compounds, carbon fixation processes, and organic matter processing in groundwater. We sampled microbial biomass from two superimposed aquifers via monitoring wells that follow groundwater flow from its recharge area through differences in hydrogeochemical settings and land use. Functional profiling revealed that groundwater microbiomes are mainly driven by nitrogen (nitrification, denitrification, and ammonium oxidation [anammox]) and to a lesser extent sulfur cycling (sulfur oxidation and sulfate reduction), depending on local hydrochemical differences. Surprisingly, the differentiation potential of the groundwater microbiome surpasses that of hydrochemistry for individual monitoring wells. Being dominated by a few phyla (Bacteroidetes,Proteobacteria,Planctomycetes, andThaumarchaeota), the taxonomic profiling of groundwater metagenomes and metatranscriptomes revealed pronounced differences between merely present microbiome members and those actively participating in community gene expression and biogeochemical cycling. Unexpectedly, we observed a constitutive expression of carbohydrate-active enzymes encoded by different microbiome members, along with the groundwater flow path. The turnover of organic carbon apparently complements for lithoautotrophic carbon assimilation pathways mainly used by the groundwater microbiome depending on the availability of oxygen and inorganic electron donors, like ammonium.IMPORTANCEGroundwater is a key resource for drinking water production and irrigation. The interplay between geological setting, hydrochemistry, carbon storage, and groundwater microbiome ecosystem functioning is crucial for our understanding of these important ecosystem services. We targeted the encoded and expressed metabolic potential of groundwater microbiomes along an aquifer transect that diversifies in terms of hydrochemistry and land use. Our results showed that the groundwater microbiome has a higher spatial differentiation potential than does hydrochemistry.

Microbial activity and phosphorus uptake on decomposing leaf detritus in a heterotrophic stream

1988 ◽  
Vol 23 (2) ◽  
pp. 1198-1208
Author(s):  
J. W. Elwood ◽  
P. J. Mulholland ◽  
J. D. Newbold
Keyword(s):  
Microbial Activity ◽  
Phosphorus Uptake

scholarly journals Changes in the nitrogen biogeochemical cycle in sediments of an urban river under different dissolved oxygen levels

2018 ◽  
Vol 19 (4) ◽  
pp. 1271-1278 ◽  
Author(s):  
Yaping Zhang ◽  
Xiaohong Ruan ◽  
Wenli Shi
Keyword(s):  
Dissolved Oxygen ◽  
Nitrogen Cycling ◽  
Quantitative Polymerase Chain Reaction ◽  
Nitrogen Transformation ◽  
Urban River ◽  
Ammonia Oxidizing Bacteria ◽  
Urban Rivers ◽  
Ammonium Oxidation ◽  
Microbial Nitrogen ◽  
Concentration Changes

Abstract Urban rivers are considered as a hot spot of microbial nitrogen cycling due to extensive N loading. However, microbial nitrogen transformation dynamics in urban rivers with different dissolved oxygen (DO) conditions are still unclear. This study investigated the effects of DO concentration changes (anaerobic to aerobic) in overlying water on nitrogen-cycling gene abundance in incubation conditions using sediment from a typical urban river in the Yangtze River Delta. Quantitative polymerase chain reaction (qPCR) results revealed that the abundances of the nitrification gene amoA, denitrification gene nirS/K, norB, nosZ, and anammox gene hzo increased by one to two orders of magnitude from anaerobic to aerobic conditions. Ammonia-oxidizing archaea (AOA) predominated the ammonium oxidation microbial populations, about tenfold more than the ammonia-oxidizing bacteria (AOB) populations. Significant correlations were found among the abundances of AOA-amoA, AOB-amoA, nirS, nirK, and hzo genes, implying a close coupling of aerobic ammonium oxidation (AAO), denitrification, and anammox processes at the molecular level. Moreover, the nitrogen transformation rates were calculated using a box model linking the measured dissolved inorganic nitrogen species. The contribution of anammox to N2 production was 85% under saturated treatment, and the AAO rate was significantly positive correlated to the anammox rate. Our results suggested that coupled AAO and anammox might be the dominant pathway for reactive nitrogen removal in urban rivers with elevated DO levels.

scholarly journals The summer soundscape of a shallow-water estuary used by beluga whales in the western Canadian Arctic

2020 ◽  
Vol 6 (4) ◽  
pp. 361-383 ◽  
Author(s):  
William D. Halliday ◽  
Kevin Scharffenberg ◽  
Dustin Whalen ◽  
Shannon A. MacPhee ◽  
Lisa L. Loseto ◽  
...  
Keyword(s):  
Marine Protected Area ◽  
River Estuary ◽  
Canadian Arctic ◽  
Time Of Day ◽  
The Arctic ◽  
Delphinapterus Leucas ◽  
Marine Animals ◽  
Frequency Bands ◽  
Beluga Whales ◽  
Important Habitat

The soundscape is an important habitat component for marine animals. In the Arctic, marine conditions are changing rapidly due to sea ice loss and increased anthropogenic activities such as shipping, which will influence the soundscape. Here, we assess the contributors to the summer soundscape in the shallow waters of the Mackenzie River estuary within the Tarium Niryutait Marine Protected Area in the western Canadian Arctic, a core summering habitat for beluga whales (Delphinapterus leucas Pallas, 1776). We collected passive acoustic data during the summer over four years, and assessed the influence of physical variables, beluga whale vocalizations, and boat noise on sound pressure levels in three frequency bands (low: 0.2–1 kHz; medium: 1–10 kHz; high: 10–48 kHz) to quantify the soundscape. Wind speed, wave height, beluga vocalizations, and boat noise were all large contributors to the soundscape in various frequency bands. The soundscape varied to a lesser degree between sites, time of day, and with tide height, but remained relatively constant between years. This study is the first detailed description of a shallow summer soundscape in the western Canadian Arctic, an important habitat for beluga whales, and can be used as a baseline to monitor future changes during this season.

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