Nutrient Enrichment and Saline Conditions Decreases Growth and Photosynthesis of the Mangrove Heritiera littoralis Dryand

Inundation associated with flooding and sea level rise is predicted to have major impacts on survival, growth and productivity of mangroves. A manipulative mesocosm experiment was conducted to assess whether nutrient enrichment enhances growth and photosynthesis of waterlogged and salinity stressed seedlings of the mangrove Heritiera littoralis Dryand. Seedlings were fertilized with a three-component granular farm NPK (Nitrogen-Phosphorous-Potassium, 20:20:20) at varied loads under waterlogging with four levels of salinity. Growth was assessed through biomass accumulation, and photosynthesis through photosynthetic quantum yield and leaf Chl content. When seedlings were exposed to both nutrient enrichment and increased salinity, a significant shift of biomass to roots was observed. Seedlings had low value of Chl a/b ratio and photosynthetic distraction resulting in mortality was high in the highest salinity and nutrient levels. These results are useful in explaining failure of regeneration in natural stands of riverine and freshwater bound mangroves following unprecedented flooding events that accrue land based nutrient loads into estuaries and deltas.

NEECF: a project of nutrient enrichment experiments in China’s forests

Anthropogenic nitrogen(N)emissions to atmosphere have increased dramatically in China since 1980s,and this increase has aroused great concerns on its ecological impacts on terrestrial ecosystems.Previous studies have showed that terrestrial ecosystems in China are acting as a large carbon(C)sink,but its potential in the future remains largely uncertain.So far little work on the impacts of the N deposition on C sequestration in China’s terrestrial ecosystems has been assessed at a national scale.Aiming to assess and predict how ecological processes especially the C cycling respond to the increasing N deposition in China’s forests,recently researchers from Peking University and their partners have established a manipulation experimental network on the ecological effects of the N deposition:Nutrient Enrichment Experiments in China’s Forests Project(NEECF).The NEECF comprises 10 experiments at 7 sites located from north to south China,covering major zonal forest vegetation in eastern China from boreal forest in Greater Khingan Mountains to tropical forests in Hainan Island.This paper introduces the framework of the NEECF project and its potential policy implications.

Increased community compositional dissimilarity alleviates species loss following nutrient enrichment at large spatial scales

Aims Anthropogenic activities have drastically increased nutrient availabil-ity,resulting in declines in species richness in many plant communi-ties.However,most previous studies have explored only species-loss patterns and mechanisms over small sampling areas,so their results might overestimate species loss at larger spatial scales.The aim of this research was to explore species diversity change patterns and species-loss rates at multiple scales in alpine meadow communities following nutrient enrichment.Specifically,we asked two closely related ques-tions:(i)do changes in species diversity and species-loss patterns differ among spatial scales?and(ii)how does community compositional dissimilarity and species turnover change among spatial scale?Methods This study was implemented in an alpine meadow community,which is regarded as one of the most sensitive and vulnerable ter-restrial ecosystems to anthropogenic nutrient enrichment.We conducted a fertilization experiment that involved the addition of nitrogen(N),phosphorus(P)and a mixture of both to a series of quadrats ranging from 1 to 16 m2 over 5 years to study the variations in the patterns of species diversity in response to nutrient additions at different spatial scales.Important Findings Our results showed that the changes in species diversity and species loss were dependent on the type of fertilization and the spatial scale.After N and NP fertilization,species diversity significantly decreased at the small scale but not at the large scale,and the rate of species loss decreased as the spatial scale increased.In contrast,the differences between the P addition and control communities were negligible at both the small and large spatial scales.N fertilization caused species to be lost from the small sampling scale,but because different species were lost from dif-ferent samples,there was an increase in compositional dissimilarity at larger spatial scales,which reduced the total number of species lost when measured at larger scales.These findings highlight spatial scale in evalu-ating the biodiversity loss after fertilization and suggest that the compo-sitional dissimilarity might play an important role in mediating species loss after fertilization.Our study significantly improved our understanding of changes in species diversity and species loss at different spatial scales under nutrient-enrichment scenarios.

Biotechnological potential of agro-industrial wastes for protein enrichment by solid-state fermentation using Aspergillus niger

This study is to assess the biotechnological potential of agro-industrial wastes of pineapple(Ananas comosus),sweet potato(Ipomoea batatas)and watermelon(Citrullus lanatus)for protein enrichment by solid-state fermentation using Aspergillus niger.Spore suspensions of A.niger were prepared with potato dextrose broth that had been supplemented with sodium chloride,ammonium nitrate and thiamine,and adjusted to pH of 5.Initial protein contents of sterile and non-sterile wastes of the pineapple,sweet potato,and watermelon were determined by the Kjeldahl method.The remaining sterile and non-sterile wastes was inoculated with spore suspensions of A.niger and incubated at temperature of 24℃ under conditions of solid-state fermentation for 14 days.Protein contents of the inoculated sterile and non-sterile wastes were determined after 7 and 14 days.The sterile wastes of pineapple,sweet potato and watermelon recorded initial percentage protein contents of 4.37,4.39,and 10.89,respectively,whereas their corresponding non-sterile wastes recorded initial percentage protein contents of 3.76,4.00,and 10.16,respectively.The results further show that percentage increase in protein content of sterile wastes after 14 days of fermentation were pineapple,35.01%;sweet potato,27.60%;and watermelon,64.40%.Percentage increase in protein content of non-sterile wastes after 14 days of fermentation were pineapple,72.34%;sweet potato,85.25%;and watermelon,80.51%.These findings affirm the biotechnological potential of pineapple,sweet potato and watermelon wastes and the importance of fungi as agents for protein enrichment of agro-industrial wastes.

Mechanisms and assessment of water eutrophication

Water eutrophication has become a worldwide environmental problem in recent years,and understanding the mechanisms of water eutrophication will help for prevention and remediation of water eutrophication.In this paper,recent advances in current status and major mechanisms of water eutrophication,assessment and evaluation criteria,and the influencing factors were reviewed.Water eutrophication in lakes,reservoirs,estuaries and rivers is widespread all over the world and the severity is increasing,especially in the developing countries like China.The assessment of water eutrophication has been advanced from simple individual parameters like total phosphorus,total nitrogen,etc.,to comprehensive indexes like total nutrient status index.The major influencing factors on water eutrophication include nutrient enrichment,hydrodynamics,environmental factors such as temperature,salinity,carbon dioxide,element balance,etc.,and microbial and biodiversity.The occurrence of water eutrophication is actually a complex function of all the possible influencing factors.The mechanisms of algal blooming are not fully understood and need to be further investigated.

Effects of Continuous Cropping of Panax notoginseng on the Properties of Rhizosphere Soil

[Objective] This experiment aimed to investigate the effects of continuous cropping of Panax notoginseng on the properties of rhizosphere soil. [Method] A total of 12 rhizospheres oil samples were collected in the fields continuously cropped with P. notoginseng for different years and the soil properties including pH value, contents of available N, available K, available P,total N, total K, total P and organic matter were determined. [Result] With the increase in the number of years of continuous cropping, seven soli indices: soil pH value, organic matter content, total N, total P, total K, available P and available K gradually increased, while available N showed a gradual downward trend. The contents of organic matter content, total N, total P, total K,available P, available K and available N after three years of continuous cropping were increased by 74.93%, 65.85%, 123.82%,18.78%, 341.67%, 120.16% and-32.16%, respectively, indicating that continuous cropping of P. notoginseng resulted in nutrient enrichment in rhizosphere soils. The pH value and available N in IBC(soil inside the border check) and UBC(soil under the border check) were higher than that in BBC(soil beside the border check), suggesting that the soil was gradually alkalized due to the continuous cropping of P. notoginseng. [Conclusion] These results suggest that pH change and nutrient imbalance may be the obstacles to the continuous cropping of P. notoginseng.

Seasonal Variability of Phytoplankton Community Structure in Relation to Different Nitrogen-Phosphorus Ratios in the Southern Coastal Waters of Zhejiang, China

With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64：1 （spring）, 32：1 （summer）, 16：1 （autumn） and 128：1,256：1 （winter） treatments, respectively. The values of Shannon-Wiener index （H） and Pielou evenness index （J） were lower in the 8：1 and 16：1 treatments in autumn test, while H value was higher in the 128：1 and 8：1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.

Water Quality Characterisation and Restoration Measures of University of Nottingham Malaysia Campus (UNMC) Lake

Nutrient enrichment has been identified as the major cause of University of Nottingham Malaysia Campus (UNMC) Lake’s water quality degradation. This study critically examines the nature, source and delivery of nutrients into the lake and observes that uncontrolled anthropogenic activities along the catchment area are the major sources. The chemical analyses of the water samples drawn from different sampling points were carried out in the laboratory and the total phosphorus readings were in the range of 20 to 55.7 μg/L with the inflow 1 recording the highest level. The chlorophyll a concentrations in the lake water were between 39 to 65 μg/L which exceeded Malaysian water quality standard. However, the silicate and nitrate levels were found to be in lower concentrations. Dissolved oxygen and pH readings obtained through in situ measurements in the lake water showed that there was oxygen depletion in the water during the night while it increased during the day, also the lake was acidic in the night and became alkaline in the day. All the findings were integrated to draw realistic restoration goals for the lake.

Recent Trends of Zostera marina (Eelgrass) in a Highly Eutrophic Coastal Lagoon in the Mid-Atlantic Region (USA)

Spatial and temporal characteristics of Zostera marina (eelgrass) in the Barnegat Bay-Little Egg Harbor Estuary are compared before (2004-2011) and after (2012-2013) major fertilizer legislation (Fertilizer Law A2290) was enacted in New Jersey (USA) to reduce nutrient inputs from fertilizers to water bodies in the state. A significant decrease of Z. marina biomass and areal cover occurred in this eutrophic estuary between 2004 and 2011 concomitantly with increasing nitrogen and phosphorus loading from the watershed. The rate of decline in aboveground and belowground biomass was significantly sharper during 2004-2006 than during 2008-2010. In 2010, Z. marina biomass dropped to a very low level (mean aboveground biomass = 7.7 g dry wt mDŽ;mean belowground biomass = 27.0 g dry wt mDŽ), persisting through the last sampling period (October-November) in 2013. Biomass and areal cover of Z. marina decreased even further after Fertilizer Law A2290 was enacted in January 2012, with the lowest values recorded from August to November each year. These low values are the result of ongoing eutrophication of the system. More seagrass monitoring and research are necessary in future years to determine if the fertilizer law will have a positive effect on Z. marina condition in the estuary over the long term.

Biomass allocation between leaf and stem regulates community-level plant nutrient resorption efficiency response to nitrogen and phosphorus additions in a temperate wetland of Northeast China

Aims Nutrient resorption is a crucial component of plant nutrient use strategy,yet the controls on the responses of community-level nutrient resorption to altered nutrient availability remain unclear.Here,we addressed two questions:(1)Did leaf and stem nutrient resorption respond consistently to increased nutrient availability?(2)Was community-level plant nutrient resorption response after nutrient enrichment driven by the intraspecific plasticity in plant nutrient resorption or by altered species composition?Methods We investigated the changes in aboveground biomass,and leaf and stem nutrient resorption of individual species after 3-year nitrogen(N)and phosphorus(P)additions,and assessed community-level nutrient resorption response to 3-year nutrient additions in a graminoid-dominated temperate wetland,Northeast China.Important Findings For both leaves and stems,N and P additions did not affect nutrient resorption efficiency,but they decreased respective nutrient resorption proficiency.Similarly,community-level N and P resorption proficiency declined with respective nutrient addition.Community-level N and P resorption efficiency was reduced by N addition primarily due to altered community composition and declined leaf:stem ratio.These results suggest that leaf and stem nutrient resorption processes exhibit consistent responses to increasing nutrient availability in the temperate wetland.These findings highlight the importance of altered species composition and biomass allocation between leaf and stem in driving community-level nutrient resorption response to nutrient enrichment.

Effects of experimental season of prescribed fire and nutrient addition on structure and function of previously grazed grassland

Aims Understanding the drivers of grassland structure and function fol-lowing livestock removal will inform grassland restoration and management.Here,we investigated the effects of fire and nutri-ent addition on structure and function in a subtropical semi-native grassland recently released from grazing in south-central Florida.We examined responses of soil nutrients,plant tissue nutrients,bio-mass of live,standing dead and litter,and plant species composi-tion to experimental annual prescribed fire applied during different seasons(wet season vs.dry season),and nutrient additions(N,P and N+P)over 9 years.Methods Experimental plots were set up in a randomized block split-plot design,with season of prescribed fire as the main treatment and nutrient addition as the subplot treatment.Species cover data were collected annually from 2002 to 2011 and plant tissue and plant biomass data were collected in 2002-2006 and 2011.Soil nutrients were analyzed in 2004,2006 and 2011.Important Findings Soil total phosphorus(P)levels increased substantially with P addition but were not influenced by prescribed fire.Addition of P and N led to increased P and N concentrations in live plant tissues,but prescribed fire reduced N in live tissue.Levels of tissue N were higher in all plots at the beginning of the exper-iment,an effect that was likely due to grazing activity prior to removal of livestock.Plant tissue N steadily declined over time in all plots,with annually burned plots declining faster than unburned plots.Prescribed fire was an important driver of standing dead and litter biomass and was important for main-taining grass biomass and percent cover.Nutrient addition was also important:the addition of both N and P was associated with greater live biomass and woody forbs.Removal of grazing,lack of prescribed fire,and addition of N+P led to a reduction of grass biomass and a large increase in biomass of a woody forb.Annual prescribed fire promoted N loss from the system by reducing standing dead and litter,but maintained desirable biomass of grasses.

Selenium,fibre,and protein enrichment of rice product:extrusion variables and product properties

Objectives:Rice has been identified as a high glycemic index(GI)food associated with obesity and diabetes.Current study investigated the replacement of rice flour and its effect on product properties using extrusion technology.Materials and Methods:High selenium yam and konjac flours were used to increase fibre and selenium contents,whereas sorghum and soy protein were added to improve protein content as well as textural properties of product.The following variables were optimized:yam flour(20%to 60%),feed moisture content(25%to 35%),and extrusion temperature(100°C to 120°C)by evaluating the breaking strength,firmness,colour,bulk density,and water absorption index(WAI)of the extruded products.Results:Results show that the extrusion temperature has a significant relationship with the products’breaking strength,WAI,and bulk density,whereas the feed moisture content influenced the WAI,bulk density,and firmness(P<0.05).The inclusion of yam flour significantly increased the firmness and yellowness(b*value)of the products(P<0.05).Sensory profiling revealed that the enriched product has comparable textural properties(stickiness,firmness,and graininess)with the commercial rice.Comparing with commercial rice,the enriched product has significantly higher antioxidant activity(163.53 vs.10.33μmol Trolox/100 g,DPPH assay),protein(13.4%vs.9.4%),fibre(12%resistant starch,9%glucomannan),and a lower GI value(69.6 vs.95.4).The enriched product also contains 15.62μg/100 g selenium,providing additional health benefit as Se-enriched functional food.Conclusions:This work has demonstrated the suitability of applying extrusion to produce a healthier alternative rice product by nutrient enrichment via rice flour substitution.