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Soil nutrients are a major limiting factor for plant biomass, yet paradoxically, some of the most productive ecosystems thrive in nutrient‐poor soils. Here, we conducted a global field survey in 421 sites across all major biomes to investigate the environmental factors controlling the ratio between plant biovolume (a proxy for aboveground plant biomass) and topsoil macronutrient content (N, P, Ca, K, Mg and S) worldwide. We found that temperature and precipitation were the most important factors associated with this ratio. Warm and wet regions exhibited higher plant biovolume to soil nutrient content ratios than cold high‐latitude regions. We also identified an intriguing trade‐off: a negative correlation between soil microbial biomass and the plant‐nutrient ratio, suggesting that higher microbial biomass might be associated with lower plant biomass relative to soil nutrient content. These findings are instrumental for a better understanding of terrestrial carbon storage and anticipating ecosystem services under climate change.

Forests in central Europe were affected by heavy bark beetle outbreak during the years 2014–2022. Decline of Norway spruce brought other species of forest trees, including the fir, to the fore. The nutritional level of silver fir is one of the studied topics. Needles in 14 Norway spruce (NS) – silver fir (SF) mixed forest stands from 4 regions in the Czech Republic have been sampled to survey their nutrition level. Nutrition of NS is often near or below the deficiency limit, while nutrition of SF was assessed as sufficient or good. Differences between both regions and tree species were found. SF drew more nutrients from the soil profile than NS on the same forest site. Differences between NS and SF in nutrient concentrations in needles were significant for N, Ca, Mg, Zn and S and non-significant for P and K.

Quantitative nutrient management has advantages, such as saving resources and improving nutrient utilization, compared with the conventional electrical conductivity management method. The growth and nutrient utilization of vegetables are affected by the integrated environmental conditions such as nutrient supply and light spectrum. This study investigated the effects of applied nutrient quantity (ANQ) (0.5, 1, 2, and 4 times (T) the absorption quantity of nutrients determined in the preliminary experiment, indicated by 0.5T, 1T, 2T, and 4T, respectively) in nutrient solution and red:blue ratio (R:B = 3:7, 7:3, and 9:1, indicated by RB3:7, RB7:3, and RB9:1, respectively) on the growth and nutrient utilization of basil plants in a plant factory with artificial lighting. Results demonstrated that the nutrient use efficiency (NUE) and the nutrient absorption efficiency (NAE) were significantly increased by the ANQ of 0.5T compared with the treatments of 1T, 2T, and 4T, irrespective of R:B ratios. Furthermore, under the ANQ of 0.5T, RB7:3 significantly increased the yield and the absorption of N and K of the basil plant compared with other R:B ratios. Therefore, the ANQ of 0.5T combined with RB7:3 was considered the optimal combination to improve the yield, NUE, and NAE of basil plants in the present study.

Dreissenids have greatly altered ecosystem function within the Great Lakes, but their effects on offshore surface sediments and infaunal communities are not well understood. This study explores the correlation among quagga mussel biomass, density of offshore benthos, and nutrients in surface sediments to understand the potential dreissenid facilitation of interactions between benthos and nutrient dynamics in lakes Michigan, Huron, and Ontario. The strongest relationships seen in this study were the positive associations between oligochaete density and quagga mussel biomass in all lakes. Weaker relationships were noted between quagga mussel biomass and surface sediment organic carbon, total phosphorus, and total nitrogen. In areas with higher mussel biomass, there were lower concentrations of organic carbon and total phosphorus in sediments, even though mussels are thought to increase the delivery of organic material into the benthos. Surface sediment total nitrogen concentrations were lower in high mussel biomass areas in Lake Ontario but not in lakes Michigan and Huron. These results support recent findings that non-native mussels can greatly alter nutrient cycles, as well as demonstrate the need for improved understanding of the effects mussel beds have on the surrounding benthic communities, and the cascading effects these changes may have for nutrient and carbon cycles.

Forested watersheds supply over two thirds of the world’s drinking water. The last decade has seen an increase in the frequency and intensity of wildfires that is threatening these source watersheds, and necessitating more expensive water treatment to address degrading water quality. Given increasing wildfire frequency in a changing climate, it is important to understand the magnitude of water quality impacts following fire. Here, we conducted a meta-analysis to explore post-fire changes in the concentrations of nitrogen (N) and phosphorus (P) species, dissolved organic carbon, and total suspended sediments in 121 sites around the world. Changes were documented over each study’s respective duration, which for 90% of sites was five years or fewer. We find concurrent increases in C, N and P species, highlighting a tight coupling between biogeochemical cycles in post-fire landscapes. We find that fire alters N and P speciation, with median increases of 40%–60% in the proportion of soluble inorganic N and P relative to total N and P. We also found that fire decreases C:N and C:P ratios, with median decreases ranging from 60% to 70%. Finally we observe a ‘hockey stick’-like response in changes to the concentration distribution, where increases in the highest concentration ranges are much greater than increases at lower concentrations. Our study documents strong heterogeneity in responses of water quality to wildfire that have been unreported so far in the literature.

The EU-water framework directive aims at nutrient reductions, since anthropogenically induced eutrophication is a major threat for coastal waters. However, phytoplankton biomass in southern Baltic Sea coastal water bodies (CWB) remains high and the underlying mechanisms are not well understood. Therefore, a CWB data set was analysed regarding changes in phytoplankton biomass and nutrient concentration of nitrogen (N) and phosphorus (P) from 2000 to 2014. It was expected to find imbalances between produced phytoplankton biomass and total nutrient concentrations. Inner CWB were cyanobacteria-dominated and showed up to five times higher chlorophyll a-concentrations compared to outer CWB with similar total phosphorus-concentrations. Phytoplankton tended to be P-limited during spring and N-limited during summer. Phytoplankton biomass and nutrient concentrations were even higher during very humid years, which indicated a close coupling of the CWB with their catchment areas. This study suggests that re-mesotrophication efforts need to consider the importance of changed phytoplankton composition and nutrient availabilities.

Here, we assess regional differences in decomposition rates of allochthonous plant detritus in the littoral zones of lake ecosystems. Specifically, we measured breakdown rates and elemental composition of aspen leaves (Populus tremuloides) over 60–70 days in 14 lakes from four lake regions located > 1000 km apart in Ontario, Canada. We found substantial differences in leaf breakdown among regions with much faster rates seen in more nutrient-rich and warmer lakes. While breakdown rates increased slightly with larger mesh size, which provided greater access by macroinvertebrates, these effects were negligible compared to those produced by regional differences in nutrients and temperature. We also found regional differences in detrital nutrient release, with variable N- or P-specific fluxes and their ratios, which indicates differential release of these nutrients back into the lake’s water column. Release ratios varied most in litterbags that showed the least mass loss, which indicates microbial uptake and release dynamics of N and P can uncouple under low nutrient conditions. Our results demonstrate that terrestrial leaf material and its associated nutrients may experience contrasting fates among lakes in the boreal landscapes with possible effects on lake nutrient cycles.

Despite management efforts, anthropogenic nutrient enrichments continue to enhance phytoplankton blooms worldwide. Release of nitrogen and phosphorus compounds not only provides surplus of nutrients but also disbalances their stoichiometry. Declines in the relative availability of dissolved silicon might induce limitation in diatoms, major primary producers with silicified shells. We studied experimentally how nutrient enrichment and resulting decline in dissolved silicon to nitrogen ratios (Si:N) affect the structure and functioning of natural plankton communities. Nitrate was added to create a range of Si:N ratios and phosphate was supplied in Redfield ratio to nitrogen. We also manipulated copepod abundance to understand the top-down effects on communities experiencing nutrient enrichment. Nitrogen and phosphorus additions resulted in a steep phytoplankton biomass increase, followed by a post-bloom decline. Phytoplankton bloom biomass was higher in high nitrogen treatments but during the post-bloom period this trend switched. Biomass was sustained longer in high Si:N treatments, indicating that silicon limitation terminates the bloom. Many diatom species did not benefit from nitrogen and phosphorus enrichment and diatom dominance ceased below Si:N of 0.4:1. Under high grazing pressure, silicate was taken up faster suggesting that silicification is important in diatom defense. Copepods shaped plankton communities via feeding on dinoflagellates, chlorophytes and the diatom Skeletonema costatum but there was no significant effect of nitrogen and phosphorus enrichment on copepod abundance. Our results, combined with previous studies, show that while nutrient concentrations define the total phytoplankton bloom biomass, resource ratios are important in sustaining biomass and determining community structure and composition.

Ecological stoichiometry can explain major trends in how interactions among species change across fertility gradients, but important questions remain. For example, stoichiometry predicts that fertilization should cause plants to reduce carbon allocation to arbuscular mycorrhizal fungi and, consequently, reduce fungal abundance, but responses in the field are highly variable. In a field experiment, we tested three hypotheses that could drive this variation: (1) fungi are nitrogen limited in very nitrogen-poor soils, so fertilization increases their abundance; (2) the N:P ratio of fertilization affects plant carbon allocation to fungi; (3) plant species differences affect fungal response. Our results support all three hypotheses: stoichiometry and species idiosyncrasies jointly determined fungal response to fertilization. We provide field evidence in support of the hypothesis that nitrogen can limit fungal abundance in temperate grasslands. We also show that fungal abundance in soil (hyphal length) differed beneath two dominant plant species: big bluestem ( Andropogon gerardii ) and smooth brome ( Bromus inermis ). These grass species also differed in the degree to which they reduced root colonization with fertilization, but these differences in allocation did not lead to differential responses to fertilization in terms of fungal abundance in the soil. This study shows that, while ecological stoichiometry is a useful framework for understanding the effects of eutrophication on this important and widespread species interaction, including these subtleties can increase the predictive power of the theory.

The nutrient ratio in wastewater discharge has a variety of ecological impacts on aquatic ecosystems. Plant species richness and identity (the presence of certain species in the community) affected the nitrogen (N), phosphorus (P), and potassium (K) removal efficiencies in constructed wetlands (CWs). However, the effects on the ratios of N/P/K are still unknown. This study conducted microcosms simulating floating CWs to explore the effects on these nutrient removal efficiencies and ratios. Results showed that (1) the presence of Canna indica decreased but the presence of Arundo donax increased effluent P and K concentrations, plant richness had no effect on effluent nutrients concentrations; (2) plant species richness only decreased the effluent P:K ratio but no effect on other effluent nutrient ratios; (3) the presence of C. indica increased but the presence of A. donax decreased effluent N:P and N:K ratios; (4) the presence of C. indica increased plant N, P, K pools through increasing plant biomass but the presence of A. donax decreased plant N, P, K pools through decreasing plant biomass. Overall, species identity surpassed species richness in affecting effluent nutrient concentrations and ratios. Assembling proper species composition could decrease effluent P and K concentrations and regulate effluent N/P/K ratios.