Biosensor for laboratory and lander‐based analysis of benthic nitrate plus nitrite distribution in marine environments

Revsbech, Niels Peter; Glud, Ronnie N.

doi:10.4319/lom.2009.7.761

Cited by 18 publications

(15 citation statements)

References 28 publications

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“…However, given the high density of infauna at the present study site, the microsensors were frequently damaged during the initial measurements, and we only obtained a total of 50 intact microprofiles during the 7 deployments. The O 2 sensors had a tip diameter of 1-5 lm, 90 % response time \0.5 s and stirring sensitivity \0.5 % (Revsbech 1989;Gundersen et al 1998), while typical NO 3 -sensors had an outer diameter of *150 lm, a 90 % response time of 1-2 min and were insensitive to stirring (Revsbech and Glud 2009). The sensors responded linearly towards solute concentrations, and the signals were calibrated against known concentrations in the bottom water and low readings in deep sediment layers that were presumed to be free of O 2 and NO 3 -.…”

Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

“…The sensors responded linearly towards solute concentrations, and the signals were calibrated against known concentrations in the bottom water and low readings in deep sediment layers that were presumed to be free of O 2 and NO 3 -. The NO 3 -microsensor is cross-sensitive to NO 2 -and N 2 O, but as the concentration of these solutes generally is well below 1 lmol L -1 in marine sediments, such potential interference was ignored (Revsbech and Glud 2009). Microprofiles were measured at a vertical resolution of 0.2 mm, and sensors were kept at each measuring depth for 2 min to ensure that the NO 3 -sensors had responded fully before recording the data.…”

Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

“…In situ microprofiles of O 2 and NO 3 -were obtained by a previously presented transecting microprofiling instrument (Glud et al 2009a) that for the respective deployments was equipped with 2-4 Clark-type O 2 microelectrodes (Revsbech 1989) and 2 NO 3 -microelectrodes (Revsbech and Glud 2009). During one deployment the instrument was also equipped with two H 2 S microsensors , but no free H 2 S could be detected in the upper 5 cm of the sediment.…”

Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

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Benthic Carbon Mineralization and Nutrient Turnover in a Scottish Sea Loch: An Integrative In Situ Study

et al. 2016

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Based on in situ microprofiles, chamber incubations and eddy covariance measurements, we investigated the benthic carbon mineralization and nutrient regeneration in a *65-m-deep sedimentation basin of Loch Etive, UK. The sediment hosted a considerable amount of infauna that was dominated by the brittle star A. filiformis. The numerous burrows were intensively irrigated enhancing the benthic in situ O 2 uptake by *50 %, and inducing highly variable redox conditions and O 2 distribution in the surface sediment as also documented by complementary laboratory-based planar optode measurements. The average benthic O 2 exchange as derived by chamber incubations and the eddy covariance approach were similar (14.9 ± 2.5 and 13.1 ± 9.0 mmol m -2 day -1 ) providing confidence in the two measuring approaches. Moreover, the non-invasive eddy approach revealed a flow-dependent benthic O 2 flux that was partly ascribed to enhanced ventilation of infauna burrows during periods of elevated flow rates. The ratio in exchange rates of RCO 2 and O 2 was close to unity, confirming that the O 2 uptake was a good proxy for the benthic carbon mineralization in this setting. The infauna activity resulted in highly dynamic redox conditions that presumably facilitated an efficient degradation of both terrestrial and marine-derived organic material. The complex O 2 dynamics of the burrow environment also concurrently stimulated nitrification and coupled denitrification rates making the sediment an efficient sink for bioavailable nitrogen. Furthermore, bioturbation mediated a high efflux of dissolved phosphorus and silicate. The study documents a high spatial and temporal variation in benthic solute exchange with important implications for benthic turnover of organic carbon and nutrients. However, more long-term in situ investigations with like approaches are required to fully understand how environmental events and spatio-temporal variations interrelate to the overall biogeochemical functioning of coastal sediments.

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Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

Section: In Situ Microprofiling Instrumentmentioning

confidence: 99%

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Benthic Carbon Mineralization and Nutrient Turnover in a Scottish Sea Loch: An Integrative In Situ Study

et al. 2016

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“…A significant positive correlation has been found earlier between OPC biovolumes and measured displacement volumes of preserved zooplankton samples, although OPC estimates tend to underestimate measured biomasses (Beaulieu et al 1999). LOPC estimates, on the other hand, seem to be only weakly correlated with the displacement volumes of entire size classes of particles (Schultes and Lopes 2009). The displacement volume method, which gives robust biomass estimates, has been described in detail by Schultes and Lopes (2009).…”

Section: Comparison Of Seston Dry Mass With Opc and Lopcderived Biomamentioning

confidence: 52%

Intercalibration of an acoustic technique, two optical ones, and a simple seston dry mass method for freshwater zooplankton sampling

Rahkola-Sorsa

Voutilainen

Viljanen

2014

Limnology & Ocean Methods

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A thorough comparison is made of conventional and automated zooplankton sampling techniques. The findings offer tools for complementing netted and weighed zooplankton biomasses with estimates based on acoustic and optic techniques, and thereby fill a gap in our knowledge concerning the suitability of acoustic and optic techniques for freshwater zooplankton sampling. Plankton abundance in six large boreal lakes with varying characteristics was determined by four independent methods: one acoustic (Acoustic Doppler Current Profiler), two optic (laboratory versions of the Optic and Laser Optic Plankton Counter), and a simple seston dry mass (DM) method. The combined DM of Chaoborus and medium-sized zooplankton (300-500 μm) explained 63% of the original variability in the acoustic backscatter strength. The correspondence between the optical measurements and DM was especially good in the case of medium-sized zooplankton. Thus the LOPCderived biomass (ESD 351-500 μm) explained 90% of variation in the DM of zooplankton of size 300-500 μm. The medium-sized fraction consisted mainly of small Cyclopoida and copepodite stages of Eudiaptomus and Daphnia. Both optical devices, and particularly the LOPC, are reliable for analyzing preserved net samples of freshwater zooplankton, but in situ estimation of zooplankton abundances on the basis of ADCP results is not reliable without simultaneous net or optical sampling. Acoustic results can be calibrated by reference to DM or LOPC-derived biomass estimates. The combined use of acoustic and optical techniques clearly improves the spatio-temporal resolution of zooplankton measurements and can thus provide closer insights into ecosystem dynamics, including the forces which regulate plankton communities. *Corresponding author. E-mail: minna.rahkola@uef.fi AcknowledgmentsWe thank the skilful staff of the R/V Muikku for carrying out the sampling in the field, and all the ex-workers of the former Ecological Institute for their assistance in the laboratory. We are grateful to Greta Waissi-Leinonen, Irina Dushkina, and Matti Koistinen for running the OPC and LOPC routines and Kirsti Kyyrönen for drawing the map. We also thank professors (emeritus) Kalevi Salonen and Jouko Sarvala for their helpful comments and suggestions that improved the clarity of the manuscript. Malcolm Hicks kindly revised the English language of the manuscript.

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“…The recently improved biosensors for NO 2 − and NO X − (NO 2 − + NO 3 − ) (Revsbech & Glud 2009) and O 2 microsensors were used to measure the concentrations and spatial distributions of NO 2 − , NO X − and O 2 in Ulva-amended sediment microcosms and in unamended controls during a 1 mo incubation experiment. NO X − profiles were modelled to study the effects of Ulva detritus enrichment on the vertical distribution and magnitude of nitrification and anaerobic NO X − consumption.…”

Section: Introductionmentioning

confidence: 99%

Changes in N cycling induced by Ulva detritus enrichment of sediments

García‐Robledo¹,

Revsbech²,

Risgaard-Petersen³

et al. 2013

Aquat. Microb. Ecol.

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Macroalgal accumulation and decomposition in shallow water environments typically result in an increase in the organic matter content of the sediment, affecting both benthic metabolism and nutrient dynamics. The present study investigates how a pulse addition of Ulva detritus to estuarine sediment influences the micro-distribution of O 2 , NO 3 − and NO 2 − within the sediment, as well as the rates of oxygen consumption, nitrification and nitrate reduction. The micro-distributions of O 2 , NO 3 − and NO 2 − were monitored with microsensors in Ulva-amended sediment microcosms and in unamended controls during a 1 mo incubation experiment. Process rates were obtained from numerical modeling of the concentration profiles. Oxygen consumption and nitrate reduction were enhanced by a factor of 2 in Ulva-amended sediment compared to the control. This led to a significant reduction in the penetration depths of oxygen and nitrate. Nitrification increased significantly in response to enhanced NH 4 + supply from decomposition of the Ulva detritus. Aerobic ammonia oxidation exceeded rates of nitrite oxidation, leading to accumulation of NO 2 − in the oxic zone of the sediment. Nitrite and NO 3 − produced via nitrification diffused up to the sediment surface, inducing a net efflux to the water column, and downwards, supporting a high rate of denitrification coupled to nitrification. The present study shows that organic enrichment with Ulva detritus enhances sediment oxygen uptake, nitrification and denitrification, the net result being loss of nitrogen from the system. This might constitute a compensating or self-restoration mechanism counteracting an increase in N in intertidal sediment affected by eutrophication-induced macroalgal blooms.

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Biosensor for laboratory and lander‐based analysis of benthic nitrate plus nitrite distribution in marine environments

Cited by 18 publications

References 28 publications

Benthic Carbon Mineralization and Nutrient Turnover in a Scottish Sea Loch: An Integrative In Situ Study

Benthic Carbon Mineralization and Nutrient Turnover in a Scottish Sea Loch: An Integrative In Situ Study

Intercalibration of an acoustic technique, two optical ones, and a simple seston dry mass method for freshwater zooplankton sampling

Changes in N cycling induced by Ulva detritus enrichment of sediments

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