scholarly journals Diversity-decomposition relationships in forests worldwide

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Liang Kou ◽  
Lei Jiang ◽  
Stephan Hättenschwiler ◽  
Miaomiao Zhang ◽  
Shuli Niu ◽  
...  
Keyword(s):  
Nutrient Dynamics ◽  
Meta Analysis ◽  
Field Studies ◽  
Phosphorus Release ◽  
Nitrogen And Phosphorus ◽  
Litter Traits ◽  
Litter Mixture ◽  
Litter Diversity ◽  
Diversity Effects ◽  
Biodiversity Effects

Plant species diversity affects carbon and nutrient cycling during litter decomposition, yet the generality of the direction of this effect and its magnitude remains uncertain. With a meta-analysis including 65 field studies across the Earth’s major forest ecosystems, we show here that decomposition was faster when litter was composed of more than one species. These positive biodiversity effects were mostly driven by temperate forests but were more variable in other forests. Litter mixture effects emerged most strongly in early decomposition stages and were related to divergence in litter quality. Litter diversity also accelerated nitrogen, but not phosphorus release, potentially indicating a decoupling of nitrogen and phosphorus cycling and perhaps a shift in ecosystem nutrient limitation with changing biodiversity. Our findings demonstrate the importance of litter diversity effects for carbon and nutrient dynamics during decomposition, and show how these effects vary with litter traits, decomposer complexity and forest characteristics.

Divergent scaling of fine-root nitrogen and phosphorus in different root diameters, orders and functional categories: A meta-analysis

2021 ◽  
Vol 495 ◽  
pp. 119384
Author(s):  
Zhiqiang Wang ◽  
Heng Huang ◽  
Buqing Yao ◽  
Jianming Deng ◽  
Zeqing Ma ◽  
...  
Keyword(s):  
Fine Root ◽  
Meta Analysis ◽  
Functional Categories ◽  
Nitrogen And Phosphorus ◽  
Root Nitrogen

Simultaneous Removal of Nitrogen and Phosphorus in Intermittently Aerated 2-Tank Activated Sludge Process Using DO and ORP-Bending-Point Control

1993 ◽  
Vol 28 (11-12) ◽  
pp. 513-521 ◽  
Author(s):  
Kousei Sasaki ◽  
Yasuji Yamamoto ◽  
Kazushi Tsumura ◽  
Shigeru Hatsumata ◽  
Masahiro Tatewaki
Keyword(s):  
Control System ◽  
Activated Sludge ◽  
Phosphorus Uptake ◽  
Material Balance ◽  
Phosphorus Release ◽  
Test Plant ◽  
Activated Sludge Process ◽  
Time Sharing ◽  
Nitrogen And Phosphorus ◽  
Time Control

The 2-tank intermittent aeration method is an anaerobic-aerobic activated sludge process of time-sharing type in which 2 complete mixing reaction tanks are connected in series, and aeration and agitation are periodically repeated in each tank. We have developed a new control system for the process which can secure anaerobic, anoxic and aerobic conditions through a combination of DO and ORP-Bending-point (corresponding to termination of denitrification) emergence time control. In the 1st tank, nitrification and phosphorus uptake occur in the aeration period, followed by denitrification and phosphorus release in the agitation. The 2nd tank performs nitrification and phosphorus uptake in the aeration and denitrification in the agitation. One cycle of aeration and agitation is approximately 2 hours. This control system was applied to the test plant (influent flow rate: 225 I/day) for two months under the conditions of HRT 16 hours and temperature 20 ±2 °C. We achieved stable and high removal ratios: TOC 94.9 %, T-N 89.4 %, and T-P 95.5 %. We also investigated the mechanisms of nitrogen and phosphorus removal and their material balance.

scholarly journals Element budgets in an Arctic mesocosm CO<sub>2</sub> perturbation study

2012 ◽  
Vol 9 (8) ◽  
pp. 11885-11924 ◽  
Author(s):  
J. Czerny ◽  
K. G. Schulz ◽  
T. Boxhammer ◽  
R. G. J. Bellerby ◽  
J. Büdenbender ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Ocean Acidification ◽  
Nutrient Dynamics ◽  
Temporal Dynamics ◽  
Nitrogen And Phosphorus ◽  
Nutrient Pools ◽  
Dissolved Organics ◽  
Elemental Stoichiometry ◽  
Element Budgets ◽  
Wall Growth

Abstract. Recent studies on the impacts of ocean acidification on pelagic communities have identified changes in carbon to nutrient dynamics with related shifts in elemental stoichiometry. In principle, mesocosm experiments provide the opportunity of determining the temporal dynamics of all relevant carbon and nutrient pools and, thus, calculating elemental budgets. In practice, attempts to budget mesocosm enclosures are often hampered by uncertainties in some of the measured pools and fluxes, in particular due to uncertainties in constraining air/sea gas exchange, particle sinking, and wall growth. In an Arctic mesocosm study on ocean acidification using KOSMOS (Kiel Off-Shore Mesocosms for future Ocean Simulation) all relevant element pools and fluxes of carbon, nitrogen and phosphorus were measured, using an improved experimental design intended to narrow down some of the mentioned uncertainties. Water column concentrations of particulate and dissolved organic and inorganic constituents were determined daily. New approaches for quantitative estimates of material sinking to the bottom of the mesocosms and gas exchange in 48 h temporal resolution, as well as estimates of wall growth were developed to close the gaps in element budgets. Future elevated pCO2 was found to enhance net autotrophic community carbon uptake in 2 of the 3 experimental phases but did not significantly affect particle elemental composition. Enhanced carbon consumption appears to result in accumulation of dissolved organic compounds under nutrient recycling summer conditions. This carbon over-consumption effect becomes evident from budget calculations, but was too small to be resolved by direct measurements of dissolved organics. The out-competing of large diatoms by comparatively small algae in nutrient uptake caused reduced production rates under future ocean CO2 conditions in the end of the experiment. This CO2 induced shift away from diatoms towards smaller phytoplankton and enhanced cycling of dissolved organics was pushing the system towards a retention type food chain with overall negative effects on export potential.

scholarly journals Nutrient dynamics along the Moskva River under heavy pollution and limited self-purification capacity

2020 ◽  
Vol 163 ◽  
pp. 05014
Author(s):  
Maria Tereshina ◽  
Oxana Erina ◽  
Dmitriy Sokolov ◽  
Lyudmila Efimova ◽  
Nikolay Kasimov
Keyword(s):  
Nutrient Dynamics ◽  
Inorganic Nitrogen ◽  
Water Quality Management ◽  
Urban Pollution ◽  
Extensive Study ◽  
Low Flow ◽  
Urban Region ◽  
Anthropogenic Pressure ◽  
Nitrogen And Phosphorus ◽  
Moskva River

An extensive study conducted during the dry summer of 2019 provided a detailed picture of the nutrient content dynamics along the Moskva River. Water sampling at 38 locations on the main river and at 17 of its tributaries revealed a manifold increase in phosphorus and nitrogen concentrations as the river crosses the Moscow metropolitan area, which can be attributed to both direct discharge of poorly treated sewage and nonpoint urban pollution. Even at the Moskva River lower reaches, where the anthropogenic pressure on the river and its tributaries is less pronounced, the inorganic nitrogen and phosphorus content remains consistently high and exceeds the environmental guidelines by up to almost 10 times. This indicates increased vulnerability of the Moskva River ecosystem during periods of low flow, which can be a major factor of eutrophication in the entire Moskva-Oka-Volga system. Comparison of our data with some archive records shows no significant improve in the nutrient pollution of the river since the 1990s, which raises further concern about the effectiveness of water quality management in Moscow urban region.

A meta-analysis of carbon, nitrogen and phosphorus change in response to conversion of grassland to agricultural land

Geoderma ◽  
2020 ◽  
Vol 363 ◽  
pp. 114149 ◽  
Author(s):  
Shucheng Li ◽  
Junhu Xu ◽  
Shiming Tang ◽  
Qiuwen Zhan ◽  
Qinghai Gao ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Meta Analysis ◽  
Nitrogen And Phosphorus
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