scholarly journals Assessing Fluorescent Organic Matter in Natural Waters: Towards In Situ Excitation–Emission Matrix Spectroscopy

2018 ◽  
Vol 8 (12) ◽  
pp. 2685 ◽  
Author(s):  
Oliver Zielinski ◽  
Nick Rüssmeier ◽  
Oliver Ferdinand ◽  
Mario Miranda ◽  
Jochen Wollschläger
Keyword(s):  
Organic Matter ◽  
Natural Waters ◽  
Field Application ◽  
Sensor System ◽  
Biogeochemical Processes ◽  
Good Correspondence ◽  
Excitation Emission Matrix ◽  
Fluorescent Dissolved Organic Matter ◽  
Rapid Changes

Natural organic matter (NOM) is a key parameter in aquatic biogeochemical processes. Part of the NOM pool exhibits optical properties, namely absorption and fluorescence. The latter is frequently utilized in laboratory measurements of its dissolved fraction (fluorescent dissolved organic matter, FDOM) through excitation–emission matrix spectroscopy (EEMS). We present the design and field application of a novel EEMS sensor system applicable in situ, the ‘Kallemeter’. Observations are based on a field campaign, starting in Norwegian coastal waters entering the Trondheimsfjord. Comparison against the bulk fluorescence of two commercial FDOM sensors exhibited a good correspondence of the different methods and the ability to resolve gradients and dynamics along the transect. Complementary laboratory EEM spectra measurements of surface water samples and their subsequent PARAFAC analysis revealed three dominant components while the ‘Kallemeter’ EEMS sensor system was able to produce reasonable EEM spectra in high DOM concentrated water bodies, yet high noise levels must be addressed in order to provide comparable PARAFAC components. Achievements and limitations of this proof-of-concept are discussed providing guidance towards full in situ EEMS measurements to resolve rapid changes and processes in natural waters based on the assessment of spectral properties. Their combination with multiwavelength FDOM sensors onboard autonomous platforms will enhance our capacities in observing biogeochemical processes in the marine environment in spatiotemporal and spectral dimensions.

Fluorescent Dissolved Organic Matter in Natural Waters

2012 ◽  
pp. 429-559 ◽  
Author(s):  
Khan M. G. Mostofa ◽  
Cong-qiang Liu ◽  
Takahito Yoshioka ◽  
Davide Vione ◽  
Yunlin Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Natural Waters ◽  
Fluorescent Dissolved Organic Matter

scholarly journals Sedimentary supply of humic-like fluorescent dissolved organic matter and its implication for chemoautotrophic microbial activity in the Izu-Ogasawara Trench

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Shigemitsu ◽  
T. Yokokawa ◽  
H. Uchida ◽  
S. Kawagucci ◽  
A. Murata
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Dissolved Organic Matter ◽  
Oxygen Utilization ◽  
Fluorescent Dissolved Organic Matter ◽  
Vertical Distributions ◽  
The Difference ◽  
The Relationship ◽  
Apparent Oxygen Utilization

AbstractMicrobial community structure in the hadal water is reported to be different from that in the upper abyssal water. However, the mechanism governing the difference has not been fully understood. In this study, we investigate the vertical distributions of humic-like fluorescent dissolved organic matter (FDOMH), chemoautotrophic production, apparent oxygen utilization (AOU), and N* in the Izu-Ogasawara Trench. In the upper abyssal waters (< 6000 m), FDOMH has a significantly positive correlation with AOU; FDOMH deviates from the relationship and increases with depth without involving the increment of AOU in the hadal waters. This suggests that FDOMH is transferred from the sediments to the hadal waters through pore water, while the FDOMH is produced in situ in the upper abyssal waters. Chemoautotrophic production and N* increases and decreases with depth in the hadal waters, respectively. This corroborates the effluxes of dissolved substances, including dissolved organic matter and electron donors from sediments, which fuels the heterotrophic/chemoautotrophic microbial communities in the hadal waters. A simple box model analysis reveals that the funnel-like trench topography facilitates the increase in dissolved substances with depth in the hadal waters, which might contribute to the unique microbiological community structure in these waters.

scholarly journals Impacts of Hurricane Disturbance on Water Quality across the Aquatic Continuum of a Blackwater River to Estuary Complex

2020 ◽  
Vol 8 (6) ◽  
pp. 412
Author(s):  
Tracey Schafer ◽  
Nicholas Ward ◽  
Paul Julian ◽  
K. Ramesh Reddy ◽  
Todd Z. Osborne
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Saline Water ◽  
System Response ◽  
Blackwater River ◽  
Fluorescent Dissolved Organic Matter ◽  
Hurricane Disturbance ◽  
Wind Velocities

Hurricanes cause landscape-scale disturbances that affect biogeochemical cycling and water quality in coastal ecosystems. During Hurricane Irma’s passage through northern Florida, water movements driven by wind velocities up to 105 km h−1 caused a salinity peak in an estuary/blackwater river complex. Water quality was monitored across the 15 km site to detect the magnitude and duration of disturbance. Saline water intruded 15 km inland into a freshwater portion of the river that peaked at a salinity of 2 psu. Due to the volume of precipitation from the hurricane, significant runoff of freshwater and dissolved organic matter (DOM) caused a decrease in salinity, dissolved oxygen (DO), and Chlorophyll-a concentrations while increasing turbidity and fluorescent dissolved organic matter (fDOM). The disturbance caused rapid changes observed by in-situ water quality monitors over a 3-week period, but some effects persisted for longer periods as shown by 3-month weekly water sampling. This disturbance caused shifts in DOM loading, altered salinity dynamics, and reshaped landscapes due to wind and wave surge both in upland marsh and downstream estuary. Hurricane disturbance temporarily and abruptly alters the aquatic continuum, and observations of system response can help us understand the mechanisms associated with ecosystem resilience and recovery.

scholarly journals Physical and biogeochemical spatial scales of variability in the East Australian Current separation from shelf glider measurements

2016 ◽  
Vol 13 (6) ◽  
pp. 1967-1975 ◽  
Author(s):  
Amandine Schaeffer ◽  
Moninya Roughan ◽  
Emlyn M. Jones ◽  
Dana White
Keyword(s):  
Organic Matter ◽  
Spatial Scales ◽  
Sampling Strategy ◽  
Coastal Processes ◽  
East Australian Current ◽  
Biogeochemical Processes ◽  
Physical Processes ◽  
In Situ Observations ◽  
Sparse Measurements

Abstract. In contrast to physical processes, biogeochemical processes are inherently patchy in the ocean, which affects both the observational sampling strategy and the representativeness of sparse measurements in data assimilating models. In situ observations from multiple glider deployments are analysed to characterize spatial scales of variability in both physical and biogeochemical properties, using an empirical statistical model. We find that decorrelation ranges are strongly dependent on the balance between local dynamics and mesoscale forcing. The shortest horizontal (5–10 km) and vertical (45 m) decorrelation ranges are for chlorophyll a fluorescence, whereas those variables that are a function of regional ocean and atmosphere dynamics (temperature and dissolved oxygen) result in anisotropic patterns with longer ranges along (28–37 km) than across the shelf (8–19 km). Variables affected by coastal processes (salinity and coloured dissolved organic matter) have an isotropic range similar to the baroclinic Rossby radius (10–15 km).

Photosensitized degradation kinetics of trace halogenated contaminants in natural waters using membrane introduction mass spectrometry as an in situ reaction monitor

2015 ◽  
Vol 14 (11) ◽  
pp. 2108-2118 ◽  
Author(s):  
Dane R. Letourneau ◽  
Chris G. Gill ◽  
Erik T. Krogh
Keyword(s):  
Mass Spectrometry ◽  
Organic Matter ◽  
Natural Waters ◽  
Degradation Kinetics ◽  
Reductive Dehalogenation ◽  
Membrane Introduction Mass Spectrometry ◽  
Naturally Occurring ◽  
On Line ◽  
Kinetics Of

On-line membrane introduction mass spectrometry used to directly measure the photosensitized reductive dehalogenation kinetics of trace aqueous halocarbons in the presence of naturally occurring dissolved organic matter.

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