Potential terrestrial influence on transparent exopolymer particle concentrations in boreal freshwaters

Attermeyer, Katrin; Andersson, Sara; Catalán, Núria; Einarsdóttir, Karólína; Groeneveld, Marloes; Székely, Anna J.; Tranvik, Lars J.

doi:10.1002/lno.11197

Cited by 11 publications

(8 citation statements)

References 57 publications

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“…Total phosphorus (TP), total nitrogen (TN) and total carbon (TOC) were measured spectrophotometrically (Perkin Elmer, Lambda 40, UV/VIS Spectrometer) using the molybdenum‐blue method (Menzel, 1965) and by catalytic thermal decomposition method (Shimadzu TNM‐L), respectively according to standard procedures. Further, ion chromatography was used to measure the concentrations of NH 4 + , NO 3 − , PO 4 3− as described previously (Attermeyer et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

Warming mediates the resistance of aquatic bacteria to invasion during community coalescence

et al. 2021

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The immigration history of communities can profoundly affect community composition. For instance, early‐arriving species can have a lasting effect on community structure by reducing the invasion success of late‐arriving ones through priority effects. This can be particularly important when early‐arriving communities coalesce with another community during dispersal (mixing) events. However, the outcome of such community coalescence is unknown as we lack knowledge on how different factors influence the persistence of early‐arriving communities and the invasion success of late‐arriving taxa. Therefore, we implemented a full‐factorial experiment with aquatic bacteria where temperature and dispersal rate of a better adapted community were manipulated to test their joint effects on the resistance of early‐arriving communities to invasion, both at community and population level. Our 16S rRNA gene sequencing‐based results showed that invasion success of better adapted late‐arriving bacteria equaled or even exceeded what we expected based on the dispersal ratios of the recipient and invading communities suggesting limited priority effects on the community level. Patterns detected at the population level, however, showed that resistance of aquatic bacteria to invasion might be strengthened by warming as higher temperatures (a) increased the sum of relative abundances of persistent bacteria in the recipient communities, and (b) restricted the total relative abundance of successfully established late‐arriving bacteria. Warming‐enhanced resistance, however, was not always found and its strengths differed between recipient communities and dispersal rates. Nevertheless, our findings highlight the potential role of warming in mitigating the effects of invasion at the population level.

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Section: Methodsmentioning

confidence: 99%

Warming mediates the resistance of aquatic bacteria to invasion during community coalescence

et al. 2021

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“…This estimated contribution is similar to the proportion of particle associated DOM removal reported here. In light of our observations, and given that EPSs are ubiquitous in peat and inland waters with strong terrestrial connection (Attermeyer et al, 2019;Chateauvert et al, 2012), we hypothesize that EPSs play an essential role in DOM processing in headwaters and warrant further attention. Importantly, most incubation studies of DOM reactivity are performed using filtered water (e.g., Koehler et al, 2012;Vähätalo et al, 2010), and thus do not address the effect of particles.…”

Section: Peat-particles Important Stimulators Of Dom Processingmentioning

confidence: 70%

“…Although we did not measure the concentration of EPS specifically, we suspect that EPS likely played an important role for both particle adsorption and microbial activity in the water with peat‐particles upon aeration. EPS are ubiquitous features in soil (Tisdall, 1994) and high concentrations of EPS have been reported for peatlands (Attermeyer et al, 2019). These substances are hydrophobic and can be very adhesive, resulting in potent adsorbents for DOM, inorganic materials, and microbes (Passow, 2002; Tisdall, 1994; Xu et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, in boreal freshwaters, enhanced microbial OM degradation on particles suggests that such biofilms are very biogeochemically active (Attermeyer et al, 2018). Peat‐particles partly consist of extracellular polymeric substances (EPSs) (Attermeyer et al, 2019; Tisdall, 1994) that are adhesive and promote DOM adsorption, and biofilm development (Passow, 2002; Tisdall, 1994; Xu et al, 2011), and thus can enhance microbial processing of OM, especially under oxic conditions (Starkey & Karr, 1984). EPSs can adsorb to clay minerals, including metal oxides (e.g., iron oxides) that are also important sorbents for DOM (Al‐Sid‐Cheikh et al, 2015; Mikutta et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

et al. 2020

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Peatlands are dominant sources of dissolved organic matter (DOM) to boreal inland waters and play important roles in the aquatic carbon cycle. Yet before peat-derived DOM enters aquatic networks, it needs to pass through peat-stream interfaces that are often characterized by transitions from anoxic or hypoxic to oxic conditions. Aeration at these interfaces may trigger processes that impact the DOM pool, and its fate downstream. Here we experimentally assessed how the aeration of iron-and organic-rich mire-waters influences biodegradation, particle-formation, and modification of DOM. In addition, we investigated how suspended peat-derived particles from mires may influence these processes. We found that within 5 days of aeration, 20% of the DOM transformed into particulate organic matter (POM). This removal was likely due to combination of mechanisms including coprecipitation with oxidized iron, aggregation, and DOM-adsorption onto peat-derived particles. Peat-derived particles promoted microbial activity, but biodegradation was a minor loss mechanism of DOM removal. Interestingly, microbial respiration accounted for only half of the oxygen loss, suggesting substantial nonrespiratory oxygen consumption. The differences observed in DOM characteristics between anoxic and aerated treatments suggest that hydrophilic, aromatic DOM coprecipitated with iron oxides in aerated samples, and the corresponding C:N analysis of generated POM revealed that these organic species were nitrogen-poor. Meanwhile, POM formed via adsorption onto peat-derived particles generated from nonaromatic DOM and more nitrogen-rich species. Hence, selective removal of DOM, dissolved iron, and thus oxygen may be important and overlooked processes in mire-dominated headwater systems. Plain Language Summary Substantial amounts of dissolved organic matter are discharged from boreal peatlands into small streams and delivered to downstream rivers and lakes, impacting water quality, freshwater ecology, and the aquatic carbon cycle. About half of this dissolved organic matter is processed and removed during downstream transport, mainly via degradation and CO 2 emission, but also through particle formation and sedimentation. Less is known about the processing in upstream systems, where peat-water emerges into small streams. These peat-stream interfaces are characterized by rapid transitions from anoxic to oxic conditions. Since oxygen exposure may promote both microbial activity and chemical reactions, e.g., coprecipitation with iron, these interfaces might be critical locations for dissolved organic matter transformations. Here we experimentally study microbial and nonbiological processing of dissolved organic matter when anoxic mire-waters are aerated. We also assess how particles found in the peat-water may stimulate these processes. Our results suggest significant nonbiological particle formation and modification of the dissolved organic matter pool when anoxic waters from peatlands are first delivered to streams. In addition, we find that natural pa...

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“…DOM flocculation may be stimulated by sunlight (von Wachenfeldt et al 2008) but is also mediated by bacterial respiration (von Wachenfeldt et al 2009) and in both cases, colored DOM appears as the main precursor of the flocs. Another major contributor to floc formation is the presence of transparent exopolymer particles (Grossart et al 1998) which are usually related to phytoplankton (de Vicente et al 2010), but also highly correlated to aromatic and terrestrial DOM (Attermeyer et al 2019).…”

Section: The Dynamic Composition Of the Dom Pool Will Impact The Global C Cycle Of Inland Watermentioning

confidence: 99%

How humans alter dissolved organic matter composition in freshwater: relevance for the Earth’s biogeochemistry

et al. 2021

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Dissolved organic matter (DOM) is recognized for its importance in freshwater ecosystems, but historical reliance on DOM quantity rather than indicators of DOM composition has led to an incomplete understanding of DOM and an underestimation of its role and importance in biogeochemical processes. A single sample of DOM can be composed of tens of thousands of distinct molecules. Each of these unique DOM molecules has their own chemical properties and reactivity or role in the environment. Human activities can modify DOM composition and recent research has uncovered distinct DOM pools laced with human markers and footprints. Here we review how land use change, climate change, nutrient pollution, browning, wildfires, and dams can change DOM composition which in turn will affect internal processing of freshwater DOM. We then describe how human-modified DOM can affect biogeochemical processes. Drought, wildfires, cultivated land use, eutrophication, climate change driven permafrost thaw, and other human stressors can shift the composition of DOM in freshwater ecosystems increasing the relative contribution of microbial-like and aliphatic components. In contrast, increases in precipitation may shift DOM towards more relatively humic-rich, allochthonous forms of DOM. These shifts in DOM pools will likely have highly contrasting effects on carbon outgassing and burial, nutrient cycles, ecosystem metabolism, metal toxicity, and the treatments needed to produce clean drinking water. A deeper understanding of the links between the chemical properties of DOM and biogeochemical dynamics can help to address important future environmental issues, such as the transfer of organic contaminants through food webs, alterations to nitrogen cycling, impacts on drinking water quality, and biogeochemical effects of global climate change.

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Potential terrestrial influence on transparent exopolymer particle concentrations in boreal freshwaters

Cited by 11 publications

References 57 publications

Warming mediates the resistance of aquatic bacteria to invasion during community coalescence

Warming mediates the resistance of aquatic bacteria to invasion during community coalescence

Particles and Aeration at Mire‐Stream Interfaces Cause Selective Removal and Modification of Dissolved Organic Matter

How humans alter dissolved organic matter composition in freshwater: relevance for the Earth’s biogeochemistry

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