Absorption properties of high-latitude Norwegian coastal water: The impact of CDOM and particulate matter

Nima, Ciren; Frette, Øyvind; Hamre, Børge; Erga, Svein Rune; Chen, Yi‐Chun; Zhao, Lu; Sørensen, Kai; Norli, Marit; Stamnes, Knut; Stamnes, Jakob J.

doi:10.1016/j.ecss.2016.05.012

Cited by 26 publications

(31 citation statements)

References 33 publications

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“…Values of a NAP (443) in this study were an order of magnitude higher than those presented by Gonçalves‐Araujo et al () in all biogeochemical provinces except in the Laptev Sea shelf, which was close to the a NAP (443) annual mean observed west of Spitsbergen in 2014. a NAP (443) was low in 2015 (0.009 ± 0.005 m −1 , n = 113), about 4 times lower than in 2014 (0.036 ± 0.018 m −1 , n = 104). The a NAP (443) variability range reported here was close to one found in European coastal waters and were higher than in Norwegian coastal waters and oligotrophic waters in the Atlantic Ocean (Babin et al, ; Nima et al, ). The a NAP (443)/ a tot‐w (443) ratio is 3–4 times greater than reported by Matsuoka et al () in the Western Arctic and by Matsuoka et al () in Arctic Ocean water synthesis and 5–6 times larger compared to values reported by Kowalczuk et al () in Nansen Basin and by Gonçalves‐Araujo et al () in Central Arctic Ocean and 2 times larger than measured in sea ice melt water by Bélanger et al ().…”

Section: Discussionsupporting

confidence: 80%

Bio‐optical Properties of Surface Waters in the Atlantic Water Inflow Region off Spitsbergen (Arctic Ocean)

et al. 2019

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Bio‐optical properties of surface waters were characterized off western and northern Spitsbergen in the summers of 2013, 2014, and 2015. We observed statistically significant year‐to‐year differences in spatial distribution of spectral absorption (a(λ)) and beam attenuation (c(λ)). Highest a(λ) and c(λ) were located in the frontal zone between water masses and co‐varied strongly with chlorophyll a fluorescence. Phytoplankton pigments dominated the absorption budget at 443 nm (50%). The contribution of chromophoric dissolved organic matter to total nonwater absorption was highest at 412 nm (42%), and detrital absorption contributed most at 550 nm (37%). Almost all inherent optical properties, except chromophoric dissolved organic matter, were highly correlated with the chlorophyll a concentration (Chla, R2 > 0.81). Relationships between Chla and the particulate and phytoplankton pigments absorption coefficients at 443 and 676 nm were characterized by significant determination coefficients (R2 > 0.73). The phytoplankton pigments line height absorption aLH(676) was found to be the most reliable optical proxy for determination of Chla, compared to total nonwater absorption, apg(676), and stimulated in situ chlorophyll a fluorescence intensity, IChla. In the presence of sea ice melt the water column was stratified and the vertical distribution of inherent optical properties was characterized by a surface minimum followed by a distinct subsurface maximum, aligned with a subsurface chlorophyll a maximum. We surmise that prevailing regional wind patterns affect sea ice and surface drift in central Fram Strait, and thus the location of sea ice meltwater, which affects the vertical stratification and occurrence of subsurface chlorophyll a maximum.

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Section: Discussionsupporting

confidence: 80%

Bio‐optical Properties of Surface Waters in the Atlantic Water Inflow Region off Spitsbergen (Arctic Ocean)

et al. 2019

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“…In contrast, values of absorption coefficients were 2 times higher in Norwegian coastal waters, which are influenced by the Lofoten Gyre, and presumably by terrestrial runoff as reported by Nima et al (2016).…”

Section: Variability In and Spectral Properties Of Cdom In The Nordicmentioning

confidence: 53%

“…Observations reported by Kowalczuk et al (2017) were conducted earlier in the season and samples were collected below sea ice; thus CDOM was less exposed to solar radiation and was potentially less affected by photobleaching. The highest S 300−600 values were found during AREX2014 (20.71 ± 5.26 µm −1 ), when over 79 % of samples were classified as AW, which could be associated with photomineralization of DOM in aging seawater (Obernosterer and Benner, 2004).…”

Section: Variability In and Spectral Properties Of Cdom In The Nordicmentioning

confidence: 95%

Characteristics of chromophoric and fluorescent dissolved organic matter in the Nordic Seas

et al. 2018

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Abstract. Optical properties of chromophoric (CDOM) and fluorescent dissolved organic matter (FDOM) were characterized in the Nordic Seas including the West Spitsbergen Shelf during June-July 2013, 2014, and 2015. The CDOM absorption coefficient at 350 nm, a CDOM (350) showed significant interannual variation (T test, p < 0.00001). In 2013, the highest average a CDOM (350) values (a CDOM (350) = 0.30 ± 0.12 m −1 ) were observed due to the influence of cold and low-salinity water from the Sørkapp Current (SC) in the southern part of the West Spitsbergen Shelf. In 2014, a CDOM (350) values were significantly lower (T test, p < 0.00001) than in 2013 (average a CDOM (350) = 0.14 ± 0.06 m −1 ), which was associated with the dominance of warm and saline Atlantic Water (AW) in the region, while in 2015 intermediate CDOM absorption (average a CDOM (350) = 0.19 ± 0.05 m −1 ) was observed. In situ measurements of three FDOM components revealed that fluorescence intensity of protein-like FDOM dominated in the surface layer of the Nordic Seas. Concentrations of marine and terrestrial humic-like DOM were very low and distribution of those components was generally vertically homogenous in the upper ocean (0-100 m). Fluorescence of terrestrial and marine humic-like DOM decreased in surface waters (0-15 m) near the sea ice edge due to dilution of oceanic waters by sea ice meltwater. The vertical distribution of protein-like FDOM was characterized by a prominent subsurface maximum that matched the subsurface chlorophyll a maximum and was observed across the study area. The highest protein-like FDOM fluorescence was observed in the Norwegian Sea in the core of warm AW. There was a significant relationship between the proteinlike fluorescence and chlorophyll a fluorescence (R 2 = 0.65, p < 0.0001, n = 24 490), which suggests that phytoplankton was the primary source of protein-like DOM in the Nordic Seas and West Spitsbergen Shelf waters. Observed variability in selected spectral indices (spectral slope coefficient, S 300-600 , carbon-specific CDOM absorption coefficient at 254 and 350 nm, SUVA 254 , a * CDOM (350)) and the nonlinear relationship between CDOM absorption and the spectral slope coefficient also indicate a dominant marine (autochthonous) source of CDOM and FDOM in the study area. Further, our data suggest that a CDOM (350) cannot be used to predict dissolved organic carbon (DOC) concentrations in the study region; however the slope coefficient (S 300-600 ) shows some promise in being used.

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“…In general, the choice of a reference absorption wavelength is arbitrary, and several values of λ 0 can be found in the literature [34]. However, 440 nm is generally chosen to be a reference wavelength because it corresponds, approximately, to the peak absorption by phytoplankton and represents the CDOM concentration, since CDOM is often measured optically at that wavelength [29,34]. S g is the spectral slope coefficient obtained using a non-linear fit within a certain wavelength range, which means how rapidly the absorption decreases with increasing wavelength.…”

Section: Discussionmentioning

confidence: 99%

“…Absorbance spectra of CDOM were measured using a dual-beam Shimadzu spectrophotometer (UV-1800, Shimadzu, Japan) over the spectral range of 280 to 900 nm with an interval of 2 nm. Baseline data were obtained by filling Milli-Q water both in the sample and reference cells, and a baseline correction was applied by subtracting the offset from each sample spectrum [29].…”

Section: Measurement Of Light Absorption Of Seawatermentioning

confidence: 99%

Diurnal Variation of Light Absorption in the Yellow River Estuary

et al. 2018

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Considering the influence of river discharge and strong winds, the diurnal variability of ocean optical absorption properties in the Yellow River Estuary (YRE) is quantified, using in-situ measurements. The study finds that terrestrial sources due to the Yellow River discharge can cause high diurnal variation of water absorption because of the movement of river plume in the YRE, but such an influence diminishes far away from the Yellow River plume. The diurnal variability of water absorption, affected by strong winds, is found to be strengthened with a rapid increase of particles and colored dissolved organic matter (CDOM) arising from re-suspended sediment induced by wave forcing. The diurnal variability of particle absorption is controlled by non-algal particle absorption in the YRE, and the ratio of non-algal particle absorption (a NAP ) and total particle absorption for most wavelengths is more than 0.56. The diurnal variation of spectral slope of non-algal particle absorption (S NAP ) is found to vary within a narrow range, although large variability in the a NAP spectrum is observed. The CDOM is correlated negatively with salinity, and such negative correlation becomes weaker with the decreasing influence of riverine input. The spectral slope of CDOM absorption (S g ) may reflect the formation and constituents of CDOM with weak relationship to its concentration, and its relationship with the absorption of CDOM at 440 nm may be associated with the source of CDOM. The value of S g , which is affected by re-suspended bottom sediment, is much lower than that derived from CDOM affected by Yellow River runoff. Disregarding the absorption of pure water, the diurnal variability of total water absorption stems principally from changes in non-algal particle matter rather than CDOM and Chl-a. By the observations of hourly GOCI (Geostationary Ocean Color Imager) data, the major diurnal variations of remote sensing reflectance at 680 nm are observed in near-coastal waters and the estuary of the Yellow River, which are mainly influenced by the flow discharge of Yellow River and strong winds. Finally, the seasonal differences of diurnal variations of water absorption caused by strong winds and river discharge are determined.

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Absorption properties of high-latitude Norwegian coastal water: The impact of CDOM and particulate matter

Cited by 26 publications

References 33 publications

Bio‐optical Properties of Surface Waters in the Atlantic Water Inflow Region off Spitsbergen (Arctic Ocean)

Bio‐optical Properties of Surface Waters in the Atlantic Water Inflow Region off Spitsbergen (Arctic Ocean)

Characteristics of chromophoric and fluorescent dissolved organic matter in the Nordic Seas

Diurnal Variation of Light Absorption in the Yellow River Estuary

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