Tracing Carbon and Nitrogen Microbial Assimilation in Suspended Particles in Freshwaters

Mena-Rivera, Leonardo; Lloyd, Charlotte; Reay, Michaela; Goodall, Tim; Read, Dan; Johnes, Penny J; Evershed, Richard P.

doi:10.21203/rs.3.rs-995821/v1

Cited by 1 publication

(1 citation statement)

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“…There are examples of compounds identified in this paper, for example the faecal biomarker compounds in the non-polar fraction that mostly likely exist not truly dissolved in the water but exist either as free-floating organics or associated with colloidal particles in the sub-0.45 µm fraction. With this in mind, along with the fact that the particulates are known to play an important role in nutrient cycling and ecosystem function (see for example Mena-Rivera et al (2022) for a detailed discussion) perhaps it is most appropriate to move away from the concept of operationally defined DOM and consider all the organic matter within a particular sample window. The methodologies presented in this paper can be applied directly, or with small modifications, to particulate samples or to unfiltered river water samples containing particles along with dissolved components to extend further the analytical window.…”

Section: Implications and Future Directionsmentioning

confidence: 99%

Characterisation of riverine dissolved organic matter using a complementary suite of chromatographic and mass spectrometric methods

et al. 2022

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Dissolved organic matter (DOM) plays a fundamental role in nutrient cycling dynamics in riverine systems. Recent research has confirmed that the concentration of riverine DOM is not the only factor regulating its functional significance; the need to define the chemical composition of DOM is a priority. Past studies of riverine DOM rested on bulk quantification, however technological advancements have meant there has been a shift towards analytical methods which allow the characterisation of DOM either at compound class or more recently molecular level. However, it is important to consider that all analytical methods only consider a defined analytical window. Thus, herein, we explore the use of a hierarchy of methods which can be used in combination for the investigation of a wide range of DOM chemistries. By using these methods to investigate the DOM composition of a range of streams draining catchments of contrasting environmental character, a wide range of compounds were identified across a range of polarities and molecular weight, thereby extending the analytical window. Through the elucidation of the DOM character in stream samples, information can be collected about likely the sources of DOM. The identification of individual key compounds within the DOM pool is a key step in the design of robust and informative bioassay experiments, used to understand in-stream ecosystem responses. This is critical if we are to assess the role of DOM as a bioavailable nutrient resource and/or ecotoxicological factor in freshwater.

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Section: Implications and Future Directionsmentioning

confidence: 99%