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McKnight, Diane M.; Harnish, R.A.; Wershaw, Robert L.; Schiff, Sherry L.

doi:10.1023/a:1005783812730

Cited by 170 publications

(12 citation statements)

References 21 publications

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“…Leachate optical characteristics (dissolved absorption coefficients and spectral slopes) were comparable to the DOM in other nearby lakes and bog water (K. Rose unpubl. ) and published values (McKnight et al 1997), indicating that the leachate could serve as a reasonable proxy of natural allochthonous DOM. After 48 h, needles were removed and the resulting solution was 0.2 mm sterile filtered.…”

Section: Methodsmentioning

confidence: 67%

Response of phytoplankton in an alpine lake to inputs of dissolved organic matter through nutrient enrichment and trophic forcing

Kissman

Williamson

Rose

et al. 2013

Limnology & Oceanography

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Inputs of terrestrially derived dissolved organic matter (DOM) are increasing in alpine lakes due to multiple drivers such as climate change, tree line advancement, and insect epidemics. A 21 d microcosm experiment investigated three potential mechanisms by which increased inputs of terrestrial DOM subsidies might affect phytoplankton density, growth, and species assemblage: (1) directly, by providing nutrients enhancing growth of select phytoplankton species (nutrient stimulation hypothesis); (2) indirectly, through trophic forcing of zooplankton uniformly increasing the total biomass of all zooplankton that selectively graze on phytoplankton (trophic intensity hypothesis); and (3) indirectly, through trophic forcing of zooplankton by favoring zooplankton species that selectively graze on phytoplankton (trophic shift hypothesis). We manipulated DOM (terrestrial DOM additions vs. unmanipulated control), zooplankton (presence vs. absence), and incubation depth (epilimnion vs. hypolimnion) in a full 3 3 3 factorial design. Phytoplankton density and growth increased substantially and species assemblage shifted to near dominance by Asterionella formosa in the presence of DOM. Zooplankton biomass and growth increased with the addition of DOM, yet the species assemblage remained stable across treatments, and contributed to selective grazing effects on phytoplankton. Our data support the nutrient stimulation and trophic intensity hypotheses. While DOM effects have been classically attributed to stimulation by addition of fixed carbon, our experiments indicate that nutrient stimulation is also important. Additionally, the indirect DOM effect of trophic forcing can occur in the absence of selective effects of DOM on zooplankton.

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Section: Methodsmentioning

confidence: 67%

Response of phytoplankton in an alpine lake to inputs of dissolved organic matter through nutrient enrichment and trophic forcing

Kissman

Williamson

Rose

et al. 2013

Limnology & Oceanography

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“…Therefore, the stronger relationship between BP and a 320 than BP versus DOC and a similar relationship between BP versus TP suggest that bacterial activity, extremely constrained by P availability, could generate CDOM. [25] A low input of allochthonous DOM from catchments appears to be a shared feature of transparent alpine lakes at the global scale [Baron et al, 1991;McKnight et al, 1997;Sommaruga et al, 1999;Laurion et al, 2000;Kamenik et al, 2001;Reche et al, 2001;Sommaruga and Augustin, 2006]. However, the current study highlights important differences between the Sierra Nevada and other alpine systems across Europe, primarily that Sierra Nevada lakes have more and greater ranges of DOC and CDOM than their counterparts in the Pyrenees and Alps [Laurion et al, 2000].…”

Section: Spatial Patterns Of Dom In Sierra Nevada Lakesmentioning

confidence: 75%

Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity

et al. 2008

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[1] The effects of many environmental stressors such as UV radiation are mediated by dissolved organic matter (DOM) properties. Therefore, determining the factors shaping spatial and temporal patterns is particularly essential in the most susceptible, low dissolved organic carbon (DOC) lakes. We analyzed spatiotemporal variations in dissolved organic carbon concentration and dissolved organic matter optical properties (absorption and fluorescence) in 11 transparent lakes located above tree line in the Sierra Nevada Mountains (Spain), and we assessed potential external (evaporation and atmospheric deposition) and internal (bacterial abundance, bacterial production, chlorophyll a, and catchment vegetation) drivers of DOM patterns. At spatial and temporal scales, bacteria were related to chromophoric DOM (CDOM). At the temporal scale, water soluble organic carbon (WSOC) in dust deposition and evaporation were found to have a significant influence on DOC and CDOM in two Sierra Nevada lakes studied during the ice-free periods of 2000-2002. DOC concentrations and absorption coefficients at 320 nm were strongly correlated over the spatial scale (n = 11, R 2 = 0.86; p < 0.01), but inconsistently correlated over time, indicating seasonal and interannual variability in external factors and a differential response of DOC concentration and CDOM to these factors. At the continental scale, higher mean DOC concentrations and more CDOM in lakes of the Sierra Nevada than in lakes of the Pyrenees and Alps may be due to a combination of more extreme evaporation, and greater atmospheric dust deposition.Citation: Mladenov, N., E. Pulido-Villena, R. Morales-Baquero, E. Ortega-Retuerta, R. Sommaruga, and I. , Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity, J. Geophys.

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“…The humic substances contribute significantly both to the CDOM pool in the water column as well as to surfactant concentrations, especially in coastal ocean, estuaries and semi-enclosed marine basins that are impacted by terrestrial runoff and marine traffic. Therefore optical methods could be used efficiently to determine of natural and anthropogenic organic surface active substances in the SML (Drozdowska et al Pereira et al, 2016;Frew et al,2004;Zhang et al, 2009;McKnight et al, 1997;Guéguen et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

et al. 2017

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Abstract. The fluorescence and absorption measurements of the samples collected from a surface microlayer (SML) and a subsurface layer (SS), at a depth of 1 m, were studied during three research cruises in the Baltic Sea along with hydrophysical studies and meteorological observations. Several absorption (E 2 : E 3 , S, S R ) and fluorescence (fluorescence intensities at Coble classified peaks: A, C, M, T the ratio (M + T ) / (A + C) , HIX (humification index)) indices of colored and fluorescent dissolved organic matter (CDOM and FDOM) helped to describe the changes in molecular size and weight as well as in composition of organic matter. The investigation allowed the assessment of a decrease in the contribution of two terrestrial components (A and C) with increasing salinity (∼ 1.64 and ∼ 1.89 % in the SML and ∼ 0.78 and ∼ 0.71 % in the SS, respectively) and an increase in components produced in situ (M and T ) with salinity (∼ 0.52 and ∼ 2.83 % in the SML and ∼ 0.98 and ∼ 1.87 % in the SS, respectively). Hence, a component T reveals the biggest relative changes along the transect from the Vistula River outlet to Gdansk Deep, in both the SML and SS, although an increase was higher in the SML than in the SS (∼ 18.5 and ∼ 12.3 %, respectively). The ratio E 2 : E 3 points to greater changes in the molecular weight of CDOM affected by a higher rate of photobleaching in the SML. The HIX index reflects a more advanced stage of humification and condensation processes in the SS. Finally, the results reveal a higher rate of degradation processes occurring in the SML than in the SS. Thus, the specific physical properties of surface active organic molecules (surfactants) may modify, in a specific way, the solar light spectrum entering the sea and a penetration depth of the solar radiation. Research on the influence of surfactants on the physical processes linked to the sea surface becomes an important task, especially in coastal waters and in the vicinity of the river mouths.

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Untitled

Cited by 170 publications

References 21 publications

Response of phytoplankton in an alpine lake to inputs of dissolved organic matter through nutrient enrichment and trophic forcing

Response of phytoplankton in an alpine lake to inputs of dissolved organic matter through nutrient enrichment and trophic forcing

Spatiotemporal drivers of dissolved organic matter in high alpine lakes: Role of Saharan dust inputs and bacterial activity

Study on organic matter fractions in the surface microlayer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

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