Letter: Trophic interactions regulate peatland carbon cycling

Wyatt, Kevin H.; McCann, Kevin S.; Rober, Allison R.; Turetsky, M. R.

doi:10.1111/ele.13697

Cited by 14 publications

(21 citation statements)

References 58 publications

(143 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While variable hydroperiods have been linked to accelerated carbon dioxide (CO 2 ) efflux from other temporary aquatic ecosystems via enhanced microbial decomposition (i.e., brown energy pathways; DelVecchia et al 2019), research from our study sites has shown that elevated algal production (green energy pathway) can offset increases in CO 2 efflux during periods of inundation (Kane et al 2021). Further, we have recently demonstrated that predatory macroinvertebrates can substantially reduce CO 2 emissions by limiting herbivore access to algal biomass, resulting in greater primary productivity and CO 2 uptake in peatlands (Wyatt et al 2021). Collectively, these findings suggest that the presence or absence of an algal-based food web has consequences for carbon cycling in temporary aquatic ecosystems.…”

Section: Discussionsupporting

confidence: 49%

Greening of the boreal peatland food web: Periphyton supports secondary production in northern peatlands

Ferguson

Slagle

McCann

et al. 2021

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

Characterizing spatial and temporal variability of food web dynamics is necessary to predict how wetter and more nutrient-rich conditions expected with climate change will influence the fate of organic matter within northern peatlands. The goals of this study were to (1) document spatial and temporal variability in the contribution of periphyton to peatland food webs using isotope analysis ( 13 C and 15 N), and (2) quantify the influence of increased nutrient availability on primary and secondary production across a gradient of rich, moderate, and poor fen peatlands common to the northern boreal biome. We established replicate m 2 plots within each fen located in interior Alaska to quantify periphyton (algae and bacteria) and macroinvertebrate biomass with and without nutrient addition throughout a growing season (May-August). Stable isotope analysis showed that periphyton contributedx = 65% of organic matter to the food web over time and across fens compared to x = 7% from plants or detritus. The transfer of basal resources was reflected in an increase in herbivore biomass as algal biomass increased over time in all fens, followed by an increase in predatory macroinvertebrates during the latter part of the growing season. Furthermore, all measures of periphyton and macroinvertebrate biomass were enhanced by nutrient addition. These data provide insight into patterns of natural variation within the aquatic food web of boreal peatlands and show that basal resources within this ecosystem, which are generally considered to be "detritus-based," are actually driven by periphyton with minimal input from plant detrital pathways.

show abstract

Section: Discussionsupporting

confidence: 49%

Greening of the boreal peatland food web: Periphyton supports secondary production in northern peatlands

Ferguson

Slagle

McCann

et al. 2021

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

show abstract

“…Water-column concentrations of nitrate (NO 3 À ) and phosphate (PO 4 À ) are typically <23 and 5 µg Á L À1 , respectively, and pH ranges from 5.5 to 6.9 during the summer growing season (Rober et al 2014). A detailed description of the site's physical and chemical characteristics has been provided in Wyatt et al (2021). This fen has a top-down food web with three trophic levels (Ferguson et al 2021); algal biofilm, herbivores, and predatory macroinvertebrates (most of which are insect larvae).…”

Section: Methodsmentioning

confidence: 99%

“…In turn, predators of algal herbivores may cause cascading trophic effects on algal assemblage structure if they control the density or foraging activities of herbivores ( Alvarez andPeckarsky 2014, Gravem andMorgan 2019). By shaping the composition of this basal resource, animals have the potential to regulate aspects of ecosystem metabolism during periods of surface-water inundation in northern peatlands (e.g., Wyatt et al 2021).…”

mentioning

confidence: 99%

Cascading effects of predators on algal size structure

Rober

McCann

Turetsky

et al. 2022

Journal of Phycology

Self Cite

View full text Add to dashboard Cite

The presence of edible and inedible prey species in a food web can influence the strength that nutrients (bottom-up) or herbivores (top-down) have on primary production. In boreal peatlands, wetter more nutrient-rich conditions associated with ongoing climate change are expanding consumer access to aquatic habitat and promoting sources of primary production (i.e., algae) that are susceptible to trophic regulation. Here, we used an in situ mesocosm experiment to evaluate the consequences of enhanced nutrient availability and food-web manipulation (herbivore and predator exclusion) on algal assemblage structure in an Alaskan fen. Owing to the potential for herbivores to selectively consume edible algae (small cells) in favor of more resistant forms, we predicted that the proportion of less-edible algae (large cells) would determine the strength of top-down or bottom-up effects. Consistent with these expectations, we observed an increase in algal-cell size in the presence of herbivores (2-tiered food web) that was absent in the presence of a trophic cascade (3-tiered food web), suggesting that predators indirectly prevented morphological changes in the algal assemblage by limiting herbivory. Increases in algal-cell size with herbivory were driven by a greater proportion of filamentous green algae and nitrogen-fixing cyanobacteria, whose size and morphological characteristics mechanically minimize consumption. While consumer-driven shifts in algal assemblage structure were significant, they did not prevent topdown regulation of biofilm development by herbivores. Our findings show that increasing wet periods in northern peatlands will provide new avenues for trophic regulation of algal production, including directly through consumption and indirectly via a trophic cascade.

show abstract

“…It is increasingly evident that biofilms regulate carbon fluxes in ecosystems, such as boreal peatlands and streams (Battin et al., 2016; Wyatt et al., 2021). In these ecosystems, the phototrophic community of biofilms ensures primary production, and their heterotrophic community ensures the decomposition and cycling of carbon and other nutrients (Bartrons et al., 2012; Battin et al., 2003; Besemer, 2015; Wu, 2017a).…”

Section: Importance Of Biofilms Growing On Non‐biological Interfacesmentioning

confidence: 99%

“…Biofilms provide the living environment for many primary consumers and are grazed by both invertebrates and vertebrates such as tadpoles (Füreder et al., 2003; Hecky & Hesslein, 1995; Rott et al., 2006). The trophic ecology of biofilms and their consumers is of particular interest given their relevance in carbon cycling: the absence of top‐down controls by animals against biofilm herbivory was shown to increase carbon dioxide emissions in boreal peatlands, highlighting the cascading effects of the loss of biodiversity (Wyatt et al., 2021). Particularly, boreal ecosystems are expected to experience changes in resource availability through climate change, shifting biofilm communities towards heterotrophy under certain conditions (Myers et al., 2021).…”

Section: Importance Of Biofilms Growing On Non‐biological Interfacesmentioning

confidence: 99%

The significance of biofilms to human, animal, plant and ecosystem health

et al. 2021

View full text Add to dashboard Cite

Biofilms are matrix‐enclosed communities that represent the most dominant and active mode of microbial life on Earth. Because biofilms are inherently more productive than any equivalent planktonic community, they are of great relevance to all environments they inhabit. However, their existence and importance are still poorly known by the general public, conservation practitioners and environmental policymakers. Most micro‐organisms of multicellular organisms (including humans, animals and plants) occur in the form of true biofilms or biofilm‐like structures that play vital roles in their development, physiology and immunity. Conversely, some biofilms can have a negative effect on host health. Biofilms growing on non‐biological surfaces are essential components of many terrestrial and marine ecosystems: they form the basis of food webs and ensure nutrient cycling and bioremediation in natural systems. However, environmental biofilms can promote the persistence of human pathogens, produce harmful toxins, foul and corrode surfaces in natural and man‐made settings; all of which can have significant health and economic implications. There is a knowledge gap about the roles of biofilms in the epidemiology of wildlife emerging infectious diseases, yet these pose a major threat to public health, biodiversity and sustainability. The drivers of global environmental change all affect biofilm structure and functions. The consequences for host and ecosystem health are, however, poorly understood. While the concept of a healthy microbiome (as opposed to dysbiosis) is emerging in medicine and conservation biology, the concept of a healthy biofilm remains to be defined in environmental sciences. Here, we use an integrative approach to (a) review current knowledge on the roles of biofilms growing on biological and non‐biological interfaces for the health of multicellular organisms and ecosystems, and (b) provide future research directions to address identified knowledge gaps. Giving the biofilm life‐form its full importance will help understand the effects of global environmental change on these communities and, in turn, on human, animal, plant and ecosystem health.

show abstract

Letter: Trophic interactions regulate peatland carbon cycling

Cited by 14 publications

References 58 publications

Greening of the boreal peatland food web: Periphyton supports secondary production in northern peatlands

Greening of the boreal peatland food web: Periphyton supports secondary production in northern peatlands

Cascading effects of predators on algal size structure

The significance of biofilms to human, animal, plant and ecosystem health

Contact Info

Product

Resources

About