A new fiber‐optic oxygen microsensor (microoptrode) based on dynamic fluorescence quenching has been developed to measure gradients in marine sediments and microbial mats. The microoptrodes are fabricated by immobilizing an oxygen‐quenchable fluorophore at the tapered tip of optical fiber. special optoelectronic system designed with these microoptrodes. It is small cheap components can easily be miniaturized for field applications. In contrast microelectrodes, easy make, do not consume...

Summary Iron (Fe 0 ) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, particular sulfate‐reducing bacteria (SRB). The characterized formation of black crusts and metal pitting. mechanism usually explained the corrosiveness formed H 2 S, scavenge ‘cathodic’ from chemical reaction Fe with O. Here we studied peculiar marine SRB that grew lithotrophically metallic iron as only electron donor. They...

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 261:75-83 (2003) - doi:10.3354/meps261075 Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique Peter Berg1,*, Hans Røy2, Felix Janssen2, Volker Meyer2, Bo Barker Jørgensen2, Markus Huettel2,3, Dirk de Beer2 1Department of Environmental Sciences, University Virginia,...

We present and compare small sediment‐water fluxes of O 2 determined with the eddy correlation technique, in situ chambers, from vertical sediment microprofiles at a 1450 m deep‐ocean site Sagami Bay, Japan. The average uptake for three approaches, respectively, was 1.62 ± 0.23 (SE, n = 7), 1.65 0.33 ( 2), 1.43 0.15 25) mmol −2 d −1 . very good agreement between flux chamber serves as new, important validation technique. It demonstrates that instrumentation available today is precise can...

To evaluate their abilities to remove colour from textile-plant effluents, tests were run using several low cost natural adsorbent materials including vermiculite, sawdust, barbecue charcoal, maize stalks, sand, rice husks and peatmoss. With the exception of more than 50% was removed wastewater, with charcoal showing best adsorptive qualities (67% 65% respectively). Under simulated industrial conditions on a laboratory scale fixed-bed reactor used investigate adsorption capacity respect...

Microsensors are powerful tools for microenvironment studies, however their use has often been restricted to laboratory applications due the lack of adequate equipment in situ deployments. Here we report on new features, construction details, and examples an improved diver-operated motorized microsensor profiler underwater field operation a water depth 25 m. The final precision 5 μm, can accommodate amperometric Clark-type microsensors oxygen hydrogen sulfide, potentiometric micro- sensors...

The aquatic eddy‐correlation technique can be used to noninvasively determine the oxygen exchange across sediment‐water interface by analyzing covariance of vertical flow velocity and concentration in a small measuring volume above sea bed. method requires fast sensors that follow rapid changes transported this calculate momentary advective flux driven turbulent motions. In article, we demonstrate optical sensors, known as optodes, represent good alternative traditional Clark‐type...

Sandy coastal sediments are global hotspots for microbial mineralization of organic matter and denitrification. These characterized by advective porewater flow, tidal cycling an active complex community. Metagenomic sequencing communities sampled from such showed that potential sulfur oxidizing Gammaproteobacteria members the enigmatic BD1-5/SN-2 candidate phylum were abundant in situ (>10% ~2% respectively). By mimicking dynamic oxic/anoxic environmental conditions sediment a laboratory...

Abstract Novel high‐pressure biotechnical systems that were developed and applied for the study of anaerobic oxidation methane (AOM) are described. The systems, referred to as continuous incubation system (HP‐CI system) manifold‐incubation (HP‐MI system), allow batch, fed‐batch, gas‐phase free at high concentrations dissolved designed meet specific demands studying environmental regulation kinetics well enriching microbial biomass in long‐term incubation. Anoxic medium is saturated with...

This contribution introduces the benthic chamber system Sandy that was developed for studying in situ solute fluxes permeable sandy sediments where advective pore‐water transport can dominate exchange across sediment‐water interface. The be deployed at seafloor, it autonomously performs measurements of fluxes. innovative features include an insertion mechanism permits gentle and deep penetration into hard consolidated sands with minimum disturbance, adjustable stirrer generates a...

We report extremely low-light-adapted anoxygenic photosynthesis in a thick microbial mat Magical Blue Hole, Abaco Island, The Bahamas. Sulfur cycling was reduced by iron oxides and organic carbon limitation. grows below the halocline/oxycline at 30 m depth on walls of flooded sinkhole. In situ irradiance surface sunny December day between 0.021 0.084 µmol photons m-2 s-1, UV light (97% sequence identity) clones affiliated with Prosthecochloris, genus within green sulfur bacteria (GSB), which...

The Dead Sea is a hypersaline lake where only few types of organisms can grow. Recently, abundant and diverse microbial life was discovered in biofilms covering rocks permeable sediments around underwater freshwater springs seeps. We used newly developed salinity mini-sensor (spatial resolution 300 μm) to investigate the environment these flume that simulates an spring. Compared with bulk water, at sediment surface decreased zero seeping velocities 7 cm s(-1). At similar flow velocities,...

We detected a controlled release of CO2 (g) with pH eddy covariance. quantified emission using measurements water velocity and in the plume aqueous generated by bubble streams, model predictions vertical dissolution its dispersion downstream. was injected 3 m below floor North Sea at rates 5.7–143 kg d − 1. Instruments were 2.6 from center streams. In absence CO2, covariance proton flux due to naturally-occurring benthic organic matter mineralization (equivalent dissolved inorganic carbon...

Seamounts, often rising hundreds of metres above surrounding seafloor, obstruct the flow deep-ocean water. While retention deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered large scale and slow rate interaction. To overcome these limitations we use growth planktonic bacteria to assess time water a seamount. The selected Tropic Seamount in North-Eastern Atlantic representative for majority isolated seamounts, which do not affect...

Abstract Response time is a central characteristic of sensors measuring solute concentrations. Knowing the response sensor under realistic conditions critically important when rapid changes, e.g., oxygen concentration fluctuations for aquatic eddy covariance flux calculations. times therefore should be determined that are similar to those exposed deployed actual measurements. This study introduces new method quantifying mini‐ or microsensors concentrations in liquids and gases. The based on...

Abstract Using microsensors O 2 concentrations were measured in photosynthetically active microbial mats of up to 3 mM, corresponding a partial pressure bar. This could damage by internal gas formation, and be inhibitory formation reactive oxygen species (ROS) reduced effectivity RuBisCo. The reliability the electrochemical was checked creating elevated water volume placed inside tank. A microsensor mounted with tip gassed bath showed response linearly proportional 5.5 mM 4 bar pure...

NOMAD is an autonomous benthic crawler carrying scientific instrumentation for scanning a continuous track of the seafloor and performing cyclic oxygen profiles in-situ measurements total exchange rates in depth up to 6000m. It expands line preceding crawlers by achieving highest payload weight ratio application function-integrating lightweight design that instantiated as low-density context underwater systems.

Calcifying organisms, including scleractinian corals and coralline algae, play a pivotal role in supporting benthic habitats their associated ecosystem functions. However, many of them are threatened by ocean warming acidification caused anthropogenic CO2 emissions. Our understanding capacity to adapt changes natural environment remains limited. To address this knowledge gap, we introduce non-invasive method quantify calcification from the simultaneous measurement H+ ion O2 fluxes utilizing...

A continuously fed, sequential anaerobic-aerobic-aerobic reactor system was used to treat wool scouring effluent. The chemical oxygen demand (COD) in the anaerobic reduced from 30500 mg/ℓ 3000-5000 mg/ℓ. In first aerobic this further 1200-1800 mg COD/l. final discharge second had a COD of 500-1000 at hydraulic retention time 2-3 d. Nitrification erratic but sufficient reduce ammonia-N levels 20 and less. Mixed liquor suspended solids volatile could be maintained sufficiently high completely...