Determination of Ellenberg’s indicator values along an elevational gradient in Central Black Sea Region of Turkey

The Central Black Sea Region has an unique vegetation because different vegetation types occurred. In the present study plant communities (from Mediterranean-type to temperate forests) in the Central Black Sea Region along an elevational gradient was evaluated on Ellenberg’s Indicator Values (EIVs). EIVs were calculated for nutrient availability, pH and temperature variables (nutrient availability (N), pH (R) and temperature (T)) with the help of weighted averages. Additionally, the vegetation of the study area was classified by using two way indicator species analyses (TWINSPAN) method and the interactions among plant species and EIVs were also studied by the help of Canonical Correspondence Analysis (CCA). We found some differences between our data and the previous data which were obtained from similar vegetation types with respect to EIV’s for nutrient availability, pH and temperature. Pteridium aquilinum, Fragaria vesca and Euphorbia amygdaloides var. amygdaloides may be used as an indicator of nutrient availability. There were significant differences among species regarding EIVs for temperature because the study area includes temperate and Mediterranean-type communities

Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota

The Asymmetric Effect of Dietary Knowledge on Nutrient Intake In China: Implications for Dietary Education Programs

This paper demonstrates that dietary knowledge can influence nutrient intake differently depending on whether expected food availability is increasing or decreasing. Using data from China, we find that overall dietary knowledge has larger and more statistically significant effects on total calorie intake and the intake of three macro nutrients (carbohydrate, fat, and protein) when expected food availability increases than when it decreases. Without distinguishing the direction of changes in expected food availability, most of the corresponding effects become smaller and statistically insignificant. Thus, the effect of dietary knowledge on nutrient intake might have been underestimated in previous studies. We discuss the implications of these findings for the design and implementation of dietary education programs.Dietary Knowledge, Nutrition, Food, China, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

2004 Great Bay Organic Nitrogen (PON & DON) and Light Extinction (PAR) Monitoring Program

Nitrogen is most often considered to be the limiting nutrient for plant growth in marine waters. As a result, knowledge of nitrogen loading and ambient water-column concentrations are considered to be critical to understanding the response of aquatic ecosystems to nutrient over-enrichment—a process known as eutrophication when it results in the excess production of organic matter. Plant production in many estuarine systems may also be limited by light availability as a result of high levels of turbidity in the water resulting from sediments, dissolved organic matter, and phytoplankton in the water column. Light limitation resulting from human-induced increases in turbidity is known to be particularly deliterious to seagrass production/distribution in some ecosystems and also play an important role in determining how phytoplankton respond to nutrient enrichment. EPA is developing water qulaity criteria for estuaries that require knowledge of both total nitrogen and light availability (measured as photsynthetically active radiation, PAR). Through the National Estuarine Research Reserve (NERR) System-Wide Monitoring Program (SWMP), inorganic nutrient concentrations, chlorophyll-a concetration, and a number of hydrographic and water quality parameters are sampled on a monthly basis at 7 sites in the Great Bay system. In addition, these same parameters, as well as bacteria concentrations, are measured at a number of sites in Great Bay and Hampton Harbor through the National Coastal Assessment (NCA) funded through the EPA. This project takes advantage of these existing monitoring activities to collect and analyze for particulate organic nitrogen (PON), dissolved organic nitrogen (DON) and photosynthetically active radiation (PAR) at a up to 10 existing sample sites in the New Hampshire seacoast region. When combined with existing dissolved inorganic nitrogen measurements, PON and DON allow the entire Total Nitrogen (TN) pool to be quantified. PAR measurements provide, for the first time, an estimate of the light availability in the system

Leaf Optical Responses to Light and Soil Nutrient Availability in Temperature Deciduous Trees

Leaf optical parameters influence light availability at the cellular, leaf, and canopy scale of integration. While recent studies have focused on leaf optical responses to acute plant stress, the effects of changes in plant resources on leaf optics remain poorly characterized. We examined leaf optical and anatomical responses of five temperate deciduous tree species to moderate changes in nutrient and light availability. Spectral reflectance in the visible waveband generally increased at high light, but decreased with increased nutrient availability. Patterns of both spectral reflectance and absorptance were primarily determined by chlorophyll concentration although carotenoid concentration was also influential. While most anatomical features did not explain residual variation in reflectance, cuticle thickness was significantly related to reflectance at complementary angles compared to the angle of incidence. Absorptance did not change with light environment; however, absorption efficiency per unit biomass increased by approximately 40% under low light, due to reduced leaf mass per area. We conclude that changes in resource availability differentially influence leaf optical properties and that such changes are driven primarily by changes in pigment concentrations. The magnitude of leaf optical responses to moderate changes in resource availability was comparable to those of acute stress responses and varied among species

The significance of atmospheric nutrient inputs and canopy interception of precipitation during ecosystem development in piñon-juniper woodlands of the southwestern USA

In arid ecosystems, widely spaced vegetation and prolonged dry periods may enhance canopy capture of nutrients from dry deposition. Additionally, differences in precipitation type, plant canopy architecture, and soil nutrient limitation could affect canopy exchange of atmospherically derived nutrients. We collected bulk precipitation and throughfall underneath piñon pine (. Pinus edulis) and one-seed juniper (. Juniperus monosperma) along a substrate age gradient to determine if canopy interception or throughfall chemistry differed among tree species, season, or substrate age. The Substrate Age Gradient of Arizona consists of four sites with substrate ages ranging from 1ky to 3000ky-old, which exhibit classic variations in soil nitrogen (N) and phosphorus (P) availability with substrate age. Greater nutrient inputs below canopies than in intercanopy areas suggest throughfall contributes to the "islands of fertility" effect. Canopy interception of precipitation did not differ between tree species, but was greater in the summer/fall than winter/spring. We found that net canopy retention of atmospherically derived N was generally greater when N availability in the soil was low, but retention also occurred when N availability was relatively high. Taken together, our results were inconclusive in determining whether the degree of soil nutrient limitation alters canopy exchange of plant growth-limiting nutrients. © 2013 Elsevier Ltd

2006 Great Bay Organic Nitrogen (PON & DON) and Light Extinction (PAR) Monitoring Program

Nitrogen is most often considered to be the limiting nutrient for plant growth in marine waters. As a result, knowledge of nitrogen loading and ambient water-column concentrations are considered to be critical to understanding the response of aquatic ecosystems to nutrient over-enrichment—a process known as eutrophication when it results in the excess production of organic matter. Plant production in many estuarine systems may also be limited by light availability as a result of high levels of turbidity in the water resulting from sediments, dissolved organic matter, and phytoplankton in the water column. Light limitation resulting from human-induced increases in turbidity is known to be particularly deliterious to seagrass production/distribution in some ecosystems and also play an important role in determining how phytoplankton respond to nutrient enrichment. EPA is developing water qulaity criteria for estuaries that require knowledge of both total nitrogen and light availability (measured as photsynthetically active radiation, PAR). Through the National Estuarine Research Reserve (NERR) System-Wide Monitoring Program (SWMP), inorganic nutrient concentrations, chlorophyll-a concetration, and a number of hydrographic and water quality parameters are sampled on a monthly basis at 7 sites in the Great Bay system. This project takes advantage of these existing monitoring activities to collect and analyze for particulate organic nitrogen (PON), dissolved organic nitrogen (DON) and photosynthetically active radiation (PAR) at existing sample sites in the New Hampshire seacoast region. When combined with existing dissolved inorganic nitrogen measurements, PON and DON allow the entire Total Nitrogen (TN) pool to be quantified. PAR measurements provide an estimate of the light availability in the system

Decomposition of coarse woody debris in a long-term litter manipulation experiment: A focus on nutrient availability

The majority of above-ground carbon in tropical forests is stored in wood, which is returned to the atmosphere during decomposition of coarse woody debris. However, the factors controlling wood decomposition have not been experimentally manipulated over time scales comparable to the length of this process.We hypothesized that wood decomposition is limited by nutrient availability and tested this hypothesis in a long-term litter addition and removal experiment in a lowland tropical forest in Panama. Specifically, we quantified decomposition using a 15-year chronosequence of decaying boles, and measured respiration rates and nutrient limitation of wood decomposer communities.The long-term probability that a dead tree completely decomposed was decreased in plots where litter was removed, but did not differ between litter addition and control treatments. Similarly, respiration rates of wood decomposer communities were greater in control treatments relative to litter removal plots; litter addition treatments did not differ from either of the other treatments. Respiration rates increased in response to nutrient addition (nitrogen, phosphorus, and potassium) in the litter removal and addition treatments, but not in the controls.Established decreases in concentrations of soil nutrients in litter removal plots and increased respiration rates in response to nutrient addition suggest that reduced rates of wood decomposition after litter removal were caused by decreased nutrient availability. The effects of litter manipulations differed directionally from a previous short-term decomposition study in the same plots, and reduced rates of bole decomposition in litter removal plots did not emerge until after more than 6 years of decomposition. These differences suggest that litter-mediated effects on nutrient dynamics have complex interactions with decomposition over time

Responses of ectomycorrhizal fungi to changes in carbon and nutrient availability

Ectomycorrhizal (ECM) fungi may receive 20% of the total C fixed by their host plants and are essential components of host nutrient acquisition. As a consequence of the vast physiological diversity that exists among ECM fungi, changes in community structure may potentially alter C and nutrient allocation and turnover within forest ecosystems. Effects of atmospheric CO2 enrichment and balanced nutrient addition on the community structure of ECM fungi were investigated. Significant effects of elevated CO2 , as well as elevated nutrient levels were found. Daily nutrient additions for 10 years did not cause reductions in the density of ECM roots or the degree of root colonisation, in contrast to other studies. Some species became more common due to nutrient additions; Cenococcum geophilum, Amphinema byssoides, Tylospora fibrillosa, tomentelloid species, and others, Piloderma byssinum and P. croceum, became less common. High variability among samples made individual species responses difficult to distinguish. Data suggest that the same species may respond similarly to both elevated CO2 and nutrient additions. In laboratory experiments, CO2 enrichment increased the production of extraradical mycelium by Hebeloma crustuliniforme, increasing mycelial spread and root colonisation. Under field conditions such a response could enable species to increase in abundance. The natural abundance of the stable isotope 13 C in fruitbodies can be used as a tool to distinguish between the two functional groups ECM and saprotrophic fungi. However, some caution is neccesary in the interpretation since values overlap between the two functional groups. The 13 C values can also be used to reveal the host-origin of carbon in mycorrhizal fungi in mixed forests. Generalist fungi, which can be associated with several different tree species, were found to receive most of their C from overstorey trees, as indicated by their high d 13 C values. This implies that large trees which are able to fix more C potentially subsidise smaller trees via a common ECM mycelial netwo

Roots and Compost, - organic crop production under reduced nutrient availability

With plans to phase out manure import from conventional farms, it will become increasingly difficult to secure plant nutrients for organic crops. In the RoCo project we will address this problem through three approaches: 1) study variation in root growth and root hair formation among cultivars of wheat, onion and lettuce, to identify superior cultivars and critical root traits which can be used as breeding objectives for new cultivars for organic farming, 2) study recirculation of urban nutrient sources through composting, to make them good fertilizers and study what make them acceptable for consumers and organic farmers, and 3) with wheat baking quality as example, study whether we can solve some of the quality problems caused by nutrient limitation by the way we use the product rather than by increasing nutrient supply in the field. We will do research within all three main themes and interactions between them, i.e. whether genotypes with superior root traits are better at using nutrients from the composts, and whether some wheat genotypes vary in their ability to utilize compost to achieve god baking quality. We will develop and test improved compost products, and develop bread baking including the use of natural additives to enhance backing quality. Demonstration activities will be related to all parts of the project. Composts will be tested for different wheat types at organic farms and differences in root traits or baking quality will be demonstrated at open field days