Source of organic detritus and bivalve biomass influences nitrogen cycling and extracellular enzyme activity in estuary sediments

Crawshaw, Josie; O’Meara, Teri; Savage, Candida; Thomson, Blair; Baltar, Federico; Thrush, Simon F.

doi:10.1007/s10533-019-00608-y

Cited by 16 publications

(6 citation statements)

References 96 publications

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“…Under these conditions, the C : N S threshold at which bacteria tend to immobilize N would be closer to 25 (Canfield et al 2005). This could explain why other studies did not find OM bulk C : N ratio a reliable metric to predict O 2 and N 2 exchange rates (Arnosti and Holmer 2003; Crawshaw et al 2019). Yet, we suggest that variation in C : N S ratio constitutes a plausible explanation for why organic N was largely more mobilized as DIN in the summer vs. spring treatments in our experiment.…”

Section: Discussionmentioning

confidence: 95%

“…Difficulties in addressing the role of OM quality as a rate‐controlling parameter also stem from the lack of standard characteristic(s) describing the nature of organic substrates (Arnosti and Holmer 2003; Aspetsberger et al 2007). Instead, a wide range of indicators have been associated to OM quality (e.g., bulk C : N : P stoichiometry, amino acid, fatty acid, or carbohydrate concentrations), with no consensus arising as to which one(s) could be most relevant for metabolic processes (Tuominen et al 1996; Arnosti and Holmer 2003; Crawshaw et al 2019). Yet, some lines of evidence suggest that the C : N ratio of organic substrates partly controls N regeneration from bacteria, and could thus have a direct influence on N cycling at the sediment–water interface (Goldman et al 1987; Tezuka 1990).…”

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confidence: 99%

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Influence of settling organic matter quantity and quality on benthic nitrogen cycling

Albert

Bonaglia

Stjärnkvist

et al. 2021

Limnology & Oceanography

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Coastal sediments are major contributors to global carbon (C) mineralization and nutrient cycling and are tightly linked to processes in the pelagic environment. In this study, we aimed to investigate the regulating potential of quantity and quality of planktonic organic matter (OM) deposition on benthic metabolism, with a particular focus on nitrogen (N) cycling processes. We simulated inputs of spring (C : N 10.9) and summer (C : N 5.6) plankton communities in high and low quantities to sediment cores, and followed oxygen consumption, nutrient fluxes as well as nitrate reduction rates, that is, denitrification and dissimilatory nitrate reduction to ammonium for 10 d. Our results demonstrate the primary importance of OM quality in determining the fate of organic N once it settles to the sediment surface. Settling of N-rich summer plankton material resulted in a $ twofold lower denitrification efficiency (40-56%) compared to N-poor spring plankton (88-115%). This indicates that N-rich plankton deposition favors recycling of inorganic nutrients to the water column over N-loss via denitrification. OM quantity was positively related to mineralization activity, but this neither directly affected N fluxes nor denitrification activity, highlighting the complex interplay between the OM quantity and quality in regulating N cycling. In light of these new findings, we support the use of simple qualitative indicators such as C : N ratio of OM to investigate how future changes in benthic-pelagic coupling might influence N budgets at the sediment-water interface.

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Section: Discussionmentioning

confidence: 95%

mentioning

confidence: 99%

Influence of settling organic matter quantity and quality on benthic nitrogen cycling

Albert

Bonaglia

Stjärnkvist

et al. 2021

Limnology & Oceanography

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“…To help evaluate soil N as well as C depolymerization, the activities of six additional hydrolytic enzymes were determined (Table 1). We interpreted protease and aminopeptidases as N-cycling enzymes since the proteinaceous substrates hydrolyzed by these enzymes are more N enriched relative to C compared with other substrates (e.g., chitin) (Berges & Mulholland, 2008;Chen et al, 2018;Crawshaw et al, 2019;Vranova et al, 2013), though soil enzymes that hydrolyze C-N bonds can be sensitive to microbial C demand (Mori, 2020: Norman et al, 2020. In 50-ml centrifuge tubes, 1 g of ovendried equivalent of soil, 4 ml of 18.2 MΩ cm −1 water and 1 ml of substrate solution at the appropriate concentration (Table 1) were added.…”

Section: Enzyme Assaysmentioning

confidence: 99%

Soil nitrogen cycling under contrasting management systems in Amazon Coffea canephora agroecosystems

López

Navarrete

Rosado

et al. 2021

Soil Science Soc of Amer J

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Robusta coffee (Coffea canephora Pierre ex Froehner) is well suited to the humid tropical climate of the Amazon basin. It is often produced under contrasting conditions of low-input agroforestry systems and intensively managed monocultures that differ in N constraints on productivity. We evaluated indicators of soil N cycling and coffee plant N sufficiency using a full factorial of two input managements (organic vs. conventional) and the absence or presence of the interplanted leguminous tree (LT) Erythrina spp. in a replicated robusta coffee field trial in the Ecuadorian Amazon. Activities of soil protease, three aminopeptidases, N-acetyl-β-D-glucosaminidase, cellobiohydrolase, and β-glucosidase were evaluated in tandem with soil NH 4 -N and NO 3 -N, potentially mineralizable N (PMN), and permanganate oxidizable C (POXC), as well as coffee leaf N, leaf N/P ratio (N/P), and yield. The LT decreased soil enzyme activities, PMN, and extractable NH 4 -N, as well as leaf N and leaf N/P. Enzyme activities and NH 4 -N were greater under organic input, but conventional input resulted in greater PMN, leaf N, leaf N/P, and yield. Permanganate oxidizable C and NO 3 -N were similar across input and interplanting but were more variable in the presence of LT relative to its absence. Lower soil enzymatic activities, labile N pools, and leaf N in coffee systems with Erythrina spp. suggest that, although a common smallholder practice in this region, interplanting this leguminous perennial has marginal impacts on soil N cycling and may not necessarily improve N supply for robusta coffee. INTRODUCTIONCoffee is an important cash crop in many developing tropical countries as the economic basis of an estimated 20 mil-

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“…Organic matter quality and quantity affect bacterial abundance and enzyme activity with higher quality OM increasing EEA (Hoppe et al 2002). For example, EEA related to N acquisition decreased in the presence of mangrove detritus (Crawshaw et al 2019). Previous studies have also shown that enzyme activity rates are highest in surface or near-surface soils and decrease with depth (Minick et al 2022) likely due to the in ux of fresh OM that stimulates microbial activity in sediment surfaces (Naylor et al 2020).…”

Section: Introductionmentioning

confidence: 93%

Sediment texture influences extracellular enzyme activity and stoichiometry across vegetated and non-vegetated coastal ecosystems

Lundquist

Schwendenmann

2022

Preprint

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The conversion of organic matter by extracellular enzymes can reveal important insights into carbon processing and nutrient cycling. The activity and stoichiometry of hydrolytic extracellular enzymes were investigated to assess the effects of sediment texture on microbially-mediated decomposition in coastal ecosystems. Enzyme activity was quantified across transects from vegetated (mangrove) to non-vegetated (tidal flat) habitats in two New Zealand coastal ecosystems that vary in sediment texture (sandy: Hobson Bay, muddy: Snells Beach). The activity of five key hydrolyzing enzymes involved in organic matter processing and nutrient cycling were determined: 1) β-glucosidase (hydrolysis of cellulose to glucose); 2) β-N-acetylglucosaminidase (catalyzes the terminal reaction in chitin degradation); 3) alkaline phosphatase (releases soluble inorganic phosphate groups from organophosphates); 4) β-D-cellobiohydrolase (hydrolyzes cellulose to generate cellobiose); and 5) β-xylosidase (catalyzes hemicellulose degradation). All enzymes had higher activity at the muddy site but enzyme activities in these coastal habitats were generally lower than has been reported for terrestrial, freshwater, and other estuarine ecosystems. Extracellular enzyme activities (EEA) did not differ between habitats at the sandy site, whereas EEA was lower in the non-vegetated habitats for some enzymes at the muddy site. Enzyme stoichiometric ratios showed that most habitats at both muddy and sandy sites were predominately C and P limited. These results can be used to advance our understanding of the biogeochemical processes underpinning the response of coastal ecosystems to land-derived nutrient and sediment inputs.

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Source of organic detritus and bivalve biomass influences nitrogen cycling and extracellular enzyme activity in estuary sediments

Cited by 16 publications

References 96 publications

Influence of settling organic matter quantity and quality on benthic nitrogen cycling

Influence of settling organic matter quantity and quality on benthic nitrogen cycling

Soil nitrogen cycling under contrasting management systems in Amazon Coffea canephora agroecosystems

Sediment texture influences extracellular enzyme activity and stoichiometry across vegetated and non-vegetated coastal ecosystems

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