The Role of Seed Banks in the Vegetation Dynamics of Prairie Glacial Marshes

The presence of viable seed in 24 substrate samples from Eagle Lake, a marsh in north—central Iowa, was tested by placing subsamples of each sample under 2 environmental conditions. One set of subsamples was placed underwater (submersed treatment). Seeds of 20 species germinated and grew in this treatment. On the average, there were 8.3 species/sample. The 2nd set of subsamples was kept moist, simulating conditions on an exposed mud flat (drawdown treatment). In the drawdown treatment, on the average, seeds of 12.9 species germinated/sample. Altogether seeds of 40 species germinated in this treatment of which only 24% were also found in the submersed treatment. By combining the results from the 2 treatments, the seed banks in the 6 vegetation types studied were estimated to range from 21,445 to 42,615 seeds/m2 on the average in the upper 5 cm of soil. Field studies at Eagle Lake (1974) and Goose Lake (1976), when these marshes had no standing water, revealed that the most abundant species whose seeds germinated on exposed mud flats were the same as the most abundant species in the experimental drawdown samples from Eagle Lake. In 1975, when Eagle Lake had standing water again, the submersed and floating species that were found were the same as those found in the experimental submersed samples from Eagle Lake. The seed—bank results and vegetation sampling reveal that there are 3 types of species present in prairie marsh seed banks: emergent species (Typha, Scirpus, Sparganium, Sagittaria) germinate on exposed mud flats or in very shallow water; submersed and free—floating species (Lemna, Spirodela, Ceratophyllum, Naias, Potamogeton) whose dormant seeds or turions can survive on exposed mud flats for a year and which germinate when there is standing water; and mud—flat species (Bidens, Cyperus, Polygonum and Rumex) which are ephemerals whose seeds can only germinate on exposed mud flats during periods when no standing water exists in the marsh because of drought or water level manipulation. When the marsh refloods, these species are eliminated from the visible marsh flora. Primarily because of the fluctuating water levels and muskrat damage, prairie marshes have cyclical changes in their vegetation during which mud—flat, emergent, or submersed and free—floating species replace each other as the dominant type of species in a marsh

Treatment of waste from a confined hog feeding unit by using artificial marshes

A 1-year study has been completed to evaluate use nf artificial marshes as a teatment system for waste from confined hog feeding operatiuns, A 3 x 2 factor ial experimental design was employed to evaluate the performance of marshes planted with one of three emergent species (Sparganium eurycarpum Phragniites austi:alis, glauca)and receiving three different loadings of hog waste. Each treatment was replicated twice, For each marsh, a complete hydrological and nutrient (N, P) budget was deter­ mined. Data on COD and solids were also collected. The growth of the plants, particularly rates of vegetative reproduction, were also monitored regularly throughout the growing season to examine the effect of sludge accumulation on plant vigor. Because the odor associated with present animal waste handling systems has been a major problem, the most important feature of artificial marshes treating hog waste is that they seem not to have developed any odors during their first year of operation . Emergent plants have a system of inter­nal air spaces that allows oxygen from the leaves to diffuse into the rhizomes and roots, Enough oxygen seems to be diffusing out of the roots and into the accumulating sludge to prevent it from becoming completely anaerobic. During the summer of 1977, the marshes produced a superior effluent to that of an anaerobic lagoon. Up to 70% of the TVS and 50% nf the COD waa re­ moved by the marshes, largely through meuhanical filtration. Approximately 17% of the N and P was removed, mostly by uptake into the plants. Design criteria for these marshes and suggested modifications are pre­sented

An empirical investigation of interaction processes between buyers and sellers of business services

The authors use this case study to investigate four interaction processes between this customer and four suppliers covering three types of business services. One of these is a semi-manufactured service – a drilling service. Two of these concern instrumental services – one is an engineering/construction service and the other involves the management of a stock of piping materials. The final process relates to a consumption service in terms of waste management. The authors find that the interaction processes in these cases are different from each other in a systematic and predictable way. The authors’ conclusion is that the ongoing interaction is a vital part of the selling and buying of business services and that the process will be closely related to structural aspects such as key objectives, functional representatives and organizational capabilities

Prairie pothole marshes as traps for nitrogen and phosphorous in agricultural runoff

Water quality of drainage influents and the lone effluent at Eagle Lake marsh, Iowa, was studied for 4 years (1976-1979). Because of drought conditions, there was no effluent from the marsh in 1976, 1977, or 1978. In 1979, the marsh was effective at removing inorganic N, especially N03-N, from runoff water passing through. It had little impact on levels of inorganic-P, total-P, and Kjeldahl-N; it was a net exporter of soluble organic carbon

Neurotransmitter transporter/receptor co-expression shares organizational traits with brain structure and function

The relationship between brain areas based on neurotransmitter receptor and transporter molecule expression patterns may provide a link between brain structure and its function. Here, we studied the organization of the receptome, a measure of regional neurotransmitter receptor/transporter molecule (NTRM) similarity, derived from in vivo PET imaging studies of 19 different receptors and transporters. Nonlinear dimensionality reduction revealed three main spatial gradients of receptor similarity in the cortex. The first gradient differentiated the somato-motor network from the remaining cortex. The second gradient spanned between temporo-occipital and frontal anchors, differentiating visual and limbic networks from attention and control networks, and the third receptome gradient was anchored between the occipital and temporal cortices. In subcortical structures, the receptome delineated a striato-thalamic axis, separating functional communities. Moreover, we observed similar organizational principles underlying receptome differentiation in cortex and subcortex, indicating a link between subcortical and cortical NTRM patterning. Overall, we found that the cortical receptome shared key organizational traits with brain structure and function. Node-level correspondence of receptor similarity to functional, microstructural, and diffusion MRI-based measures decreased along a primary-to-transmodal gradient. Compared to primary and paralimbic regions, we observed higher receptomic diversification in unimodal and heteromodal regions, possibly supporting functional flexibility. In sum, we show how receptor similarity may form an additional organizational layer of human brain architecture, bridging brain structure and function

Interdisciplinarity and transdisciplinarity in landscape studies - the Wageningen DELTA approach

Explanation of the Dutch approach of landscape research, planning and managemen

Heritability and cross-species comparisons of human cortical functional organization asymmetry

The human cerebral cortex is symmetrically organized along large-scale axes but also presents inter-hemispheric differences in structure and function. The quantified contralateral homologous difference, that is asymmetry, is a key feature of the human brain left-right axis supporting functional processes, such as language. Here, we assessed whether the asymmetry of cortical functional organization is heritable and phylogenetically conserved between humans and macaques. Our findings indicate asymmetric organization along an axis describing a functional trajectory from perceptual/action to abstract cognition. Whereas language network showed leftward asymmetric organization, frontoparietal network showed rightward asymmetric organization in humans. These asymmetries were heritable in humans and showed a similar spatial distribution with macaques, in the case of intra-hemispheric asymmetry of functional hierarchy. This suggests (phylo)genetic conservation. However, both language and frontoparietal networks showed a qualitatively larger asymmetry in humans relative to macaques. Overall, our findings suggest a genetic basis for asymmetry in intrinsic functional organization, linked to higher order cognitive functions uniquely developed in humans

Personality and local brain structure: Their shared genetic basis and reproducibility

Local cortical architecture is highly heritable and distinct genes are associated with specific cortical regions. Total surface area has been shown to be genetically correlated with complex cognitive capacities, suggesting cortical brain structure is a viable endophenotype linking genes to behavior. However, to what extend local brain structure has a genetic association with cognitive and emotional functioning is incompletely understood. Here, we study the genetic correlation between personality traits and local cortical structure in a large-scale twin sample (Human Connectome Project, n ​= ​1102, 22-37y) and we evaluated whether observed associations reflect generalizable relationships between personality and local brain structure two independent age-matched samples (Brain Genomics Superstructure Project: n ​= ​925, age ​= ​19-35y, enhanced Nathan Kline Institute dataset: n ​= ​209, age: 19-39y). We found a genetic overlap between personality traits and local cortical structure in 10 of 18 observed phenotypic associations in predominantly frontal cortices. However, we only observed evidence in favor of replication for the negative association between surface area in medial prefrontal cortex and Neuroticism in both replication samples. Quantitative functional decoding indicated this region is implicated in emotional and socio-cognitive functional processes. In sum, our observations suggest that associations between local brain structure and personality are, in part, under genetic control. However, associations are weak and only the relation between frontal surface area and Neuroticism was consistently observed across three independent samples of young adults

Current and future technical, economic and environmental feasibility of maize and wheat residues supply for biomass energy application:Illustrated for South Africa

AbstractThis study assessed the feasibility of mobilising maize and wheat residues for large-scale bioenergy applications in South Africa by establishing sustainable residue removal rates and cost of supply based on different production regions. A key objective was to refine the methodology for estimating crop residue harvesting for bioenergy use, while maintaining soil productivity and avoiding displacement of competing residue uses. At current conditions, the sustainable bioenergy potential from maize and wheat residues was estimated to be about 104 PJ. There is potential to increase the amount of crop residues to 238 PJ through measures such as no till cultivation and adopting improved cropping systems. These estimates were based on minimum residues requirements of 2 t ha−1 for soil erosion control and additional residue amounts to maintain 2% SOC level.At the farm gate, crop residues cost between 0.9 and 1.7 $GJ−1. About 96$ GJ−1. In the improved scenario, up to 85% of the biomass is below 1.3 $GJ−1. For biomass deliveries at the conversion plant, about 36$ GJ−1 while in the optimised scenario, about 87% is delivered below 5$ GJ−1. Co-firing residues with coal results in lower cost of electricity compared to other renewables and significant GHG (CO2 eq) emissions reduction (up to 0.72 tons MWh−1). Establishing sustainable crop residue supply systems in South Africa could start by utilising the existing agricultural infrastructure to secure supply and develop a functional market. It would then be necessary to incentivise improvements across the value chain