With different functional groups and hydrophobic/hydrophilic properties, natural organic matters (NOMs) displayed different combining capacities with metal ions. By using XAD-4 and DAX-8 resins, NOMs in natural lake were isolated into three fractions, i.e., HoB (hydrophobic base), HoA (hydrophobic acid) and HiM (hydrophilic matter). Afterwards, influences on Cu(II) adsorption onto titanate nanotubes (TNTs) were compared with varying NOMs and initial pH. As results, HoB can significantly control Cu(II) adsorption at pH 5, with the adsorption capacity increased 15% for 0.5 mg L−1 of HoB (ca. 120 mg g−1), which could be attributed to the formation of HoB-Cu complexation and electrostatic bridge effect of HoB with optimal concentration. Due to the easier ionization and complexation with Cu(II) at lower pH, HoA showed more obvious impaction on Cu(II) adsorption at pH 2. While HiM can influence Cu(II) adsorption at all pH ranges due to its hydrophilic groups and weak affinity to both TNTs and Cu(II). Furthermore, HoB dramatically changed the Langmuir model, with sharp increase of adsorption capacity as equilibrium Cu(II) increased, suggesting its significant involvement in Cu(II) adsorption. X-ray photoelectron spectroscopy (XPS) analysis revealed the absorbed Cu(II) existed in the form of TNTs‑OCu, TNTs‑COOCu and Cu(OH)2, proving Cu(II) adsorption mechanism including both direct adsorption by TNTs and bridging connection with NOMs. Moreover, the CO and OCO groups content ranked as HiM > HoB > HoA, while TNTs‑COOCu content ranked as HoA > HoB > HiM, suggesting HoB had the moderate connection with both TNTs and Cu(II), thus the impact on Cu(II) adsorption was remarkable.
Facing the potential conflict between economic and environmental challenges, it is essential to investigate the integrated GHG emissions and the emission relationships of all industries in a socio-economic system to support formulation of industrially related legislation. In this study, a disaggregated ecologically-extended input-output (DECEIO) model is developed to investigate integrated GHG emissions and the emission relationships of various industries. A special case study for the Province of Saskatchewan, Canada, is conducted to illustrate the potential benefits of its use in the formulation of industrially related legislation. A disaggregated analysis that contains three GHG types and four emission sources is conducted to gain more insight into the complicated interactions between different industries. It is found that all kinds of emission sources and GHG types should be considered to comprehensively identify the characteristics of emission flows in the socio-economic system. The competitive relationships reflect good interactions in the GHG emission flows and a mutualism relationship reveals effective pathways to mitigate carbon emissions in two sectors simultaneously. In the Province of Saskatchewan, the Agriculture and Forestry sector, Electric Power Generation, Transmission and Distribution sector, Construction sector and Household Consumption sector all rank at the top for GHG emissions and their relationships are mutualistic. Thus, it is vital to propose effective industrial legislation for these industries to realize GHG emission reduction targets.
Sustaining multiple ecosystem service benefits in transboundary river basins is a complex and challenging task in the developing world. This can be attributed to conflicting conservation and human development needs and exacerbated by climate change impacts, especially episodic drought and flooding events. We use a case study from Rwanda in the Kagera River Basin in Eastern Africa to contextualize and examine how land use cover change, water access, and agro-ecosystems are vulnerable to myriad human and natural drivers of change. An integrated framework is employed for a nested social-ecological assessment of ecosystem service benefits drawing upon landscape and vulnerability mapping, agro-commodity value chains, and institutional analyses. The conceptual framework and case study provide leverage points for vertical and horizontal linkages that include cross-sectoral partnerships, multi-level governing networks, integrated water resource management, and livelihood security. Moreover, synergy between development and conservation outcomes can be achieved through joint adaptation planning and stewardship initiatives at the local district level with full participation of resource users and community leaders. These lessons from Rwanda and the Kagera River Basin provide opportunities for mainstreaming adaptation and development planning and building resilience towards regional environmental change in Eastern Africa.
Intraguild predation (IGP), i.e. feeding interaction between two consumers that share the same resource species, is commonly observed in natural food webs. IGP expands vertical niche space and slows down energy flows from lower to higher trophic levels, which potentially affects the diversity and dynamics of food webs. Here, we use food web models to investigate the effects of IGP on species diversity and ecosystem functioning. We first simulate a five‐species food web module with different strengths of IGP at the herbivore and/or carnivore level. Results show that as the strength of IGP within a trophic level increases, the biomass of its resource level increases because of predation release; this increased biomass in turn alters the energy fluxes and biomass of other trophic levels. These results are then extended by subsequent simulations of more diverse food webs. As the strength of IGP increases, simulated food webs maintain (1) higher species diversity at different trophic levels, (2) higher total biomasses at different trophic levels, and (3) larger energy fluxes across trophic levels. Our results challenge the intuitive hypothesis that food web structure should maximize the efficiency of energy transfer across trophic levels; instead, they suggest that the assembly of food webs should be governed by a balance between efficiency (of energy transfer) and persistence (i.e. the maintenance of species and biomasses). Our simulations also show that the relationship between biodiversity and ecosystem functioning (e.g. total biomass or primary production) is much stronger in the presence of IGP, reconciling the contrast from recent studies based on food‐chain and food‐web models. Our findings shed new light on the functional role of IGP and contribute to resolving the debate on structure, diversity and functioning in complex food webs. This article is protected by copyright. All rights reserved.