Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues

Abstract

Abstract.Mosses contribute an average of 20% of upland boreal forest net primary productivity and are frequently observed to degrade slowly compared to vascular plants. If this is caused primarily by the chemically complexity of their tissues, moss decomposition could exhibit high temperature sensitivity (measured as Q10) due to high activation energy, which would imply soil organic carbon (SOC) stocks derived from moss remains are especially vulnerable to decomposition with warming. Alternatively, the physical structure of the moss cell wall biochemical matrix could 20 inhibit decomposition, resulting in low decay rates and low temperature sensitivity. We tested these hypotheses by incubating mosses collected from two boreal forests in Newfoundland, Canada, for 959 days at 5 and 18°C, while monitoring changes in the moss tissue composition using total hydrolysable amino acid (THAA) analysis and 13 C NMR spectroscopy. Less than 40% of C was respired in all incubations, revealing a large pool of apparently recalcitrant C. The decay rate of the labile fraction increased in the warmer treatment, but the total amount of C loss 25 increased only slightly, resulting in low Q10 values (1.23-1.33) compared to L horizon soils collected from the same forests. NMR spectra were dominated by O-alkyl C throughout the experiment, indicating the persistence of potentially labile C. Accumulation of hydroxyproline (derived primarily from plant cell wall proteins) and aromatic C indicates selective preservation of biochemicals associated with the moss cell wall. This was supported by scanning electron microscope (SEM) images of the moss tissues, which revealed few changes in the physical structure of the 30 cell wall after incubation. This suggests the moss cell wall matrix protected labile C from microbial decomposition, accounting for the low temperature sensitivity of moss decomposition despite low decay rates. Climate drivers of moss biomass and productivity, therefore, represent a potentially important regulator of boreal forest SOC responses to climate change that needs to be assessed to improve our understanding of carbon-climate feedbacks.

Ecological stoichiometric characteristics of soil-moss C, N, and P in restoration stages of karst rocky desertification

“…Notably, this study showed that the average SOC and soil TN contents of mosses in the shrub habitat were 133.35 g/kg and 9.99 g/kg, respectively; these values were significantly higher than the SOC and soil TN in the vegetated areas of the Maolan karst forest (54.72 g/kg and 4.67 g/kg) [ 33 ] and karst rocky desertification-affected secondary forests (80.40 g/kg and 2.80 g/kg) [ 32 ]. Mosses have a slower decomposition rate than vascular plants, resulting in high organic matter content in moss substrates [ 34 ]. Moreover, mosses can form symbiotic relationships with blue algae [ 35 ].…”

Substrate quality of drained organic soils—Implications for carbon dioxide fluxes

“…The occurrence of sphagnan, which is a polysaccharide, could have contributed to higher shares of O‐alkyl, di‐O‐alkyl, hemicellulose and cellulose in the bog subsoils than in the fen subsoils. Furthermore, high shares of O‐alkyl are common in mosses (Maksimova et al., 2013; Philben et al., 2018), which are the dominant peat‐forming plants in bogs.…”

Magnetically Functionalized Moss Biomass as Biosorbent for Efficient Co2+ Ions and Thioflavin T Removal

“…In addition, four adsorption–desorption cycles practically did not affect the magnetic separation of biosorbent ( Figure 11 ), confirming the very good stability of microwave synthesized nanoparticles and microparticles of iron oxides impregnated on the biomass surface also in an acidic environment (0.1 M HCl and 0.1 M CH 3 COOH), which is in agreement with the study of Wang et al [ 43 ]. Moreover, as was pointed out by Philben et al [ 44 ], the physical and chemical structure of moss cell walls cause their high persistence in the environment, and this could also contribute to their notable biocomposite stability.…”