An individual-based analysis of the dynamics of two coexisting phytoplankton species in the mixed layer

In marine ecosystems ecological and environmental conditions continuously change, possibly supporting the wide range of phytoplankton species coexisting in aquatic environments. Phytoplankton communities are not homogeneously distributed in the water column due to the spatial and temporal variability of turbulent mixing and the concurrent biological response. In this paper an individual-based model (Lagrangian method) simulating the basic physiology of two coexisting phytoplankton species has been developed. The species, sharing the same availability of light and nutrient resource, are characterized by different photo-physiological parameters. The spatial and temporal evolution of turbulent mixing is simulated introducing vertical profiles of measured eddy diffusivity. Three case studies have been examined to analyze the role of environment–individual interactions in determining bloom conditions for both the selected species. The organisms experience recurrent fluctuations of light, temperature, and nutrient concentration gradients, due to the turbulent mixing in the water column, which have significant effects on the growth of the phytoplankton species. In all the numerical experiments, the temporal and spatial variability of different forcings do not support the prevalence of one species over the other over the time scale typical of a phytoplankton bloom.A well mixed water column favours the growth of both the populations while a variable mixing regime limits their growth reducing the photophysiological differences between the species.     

Einsatz der Hassediagrammtechnik zum Vergleich von Bergbaubetrieben unter dem Aspekt der Nachhaltigkeit

Ziel und Hintergrund

Der Vergleich von Bergwerken unter dem Gesichtspunkt einer nachhaltigen Entwicklung erfordert die Berücksichtigung einer Vielzahl von Kriterien die gleichermaßen ökonomische, ökologische und soziale Aspekte berücksichtigen. Bergwerksbetreiber stehen bei ihren strategischen und operativen Entscheidungen vor der Schwierigkeit diese Kriterien angemessen zu berücksichtigen. Durch den Einsatz, der HDT wird die Komplexität der Entscheidungssituation reduziert. Sie unterstützt die Aufbereitung der verfügbaren Informationen und erleichtert so die Entscheidungsfindung.

Methodik

Das Ziel einer nachhaltigen Entwicklung im Bergbau kann durch den Einsatz von Indikatoren konkretisiert werden. Im Rahmen dieser Arbeit erfolgt ein Vergleich ausgewählter Bergwerke durch die Definition geeigneter Indikatoren, ihre numerische Belegung und durch ihre Verwendung in der HDT. Dabei werden verschiedene methodische Aspekte wie die Klassifizierung von Daten, deren Aggregierung und Gewichtung sowie die Einbeziehung von Expertenwissen dargestellt.

Ergebnisse

Am Beispiel ausgewählter Bergwerke wird gezeigt, dass eine Sortierung der Bergwerke anhand ihrer charakteristischen und als wesentlich erachteten Eigenschaften möglich ist. Durch den Einsatz der Hassediagrammtechnik wird die Komplexität der Entscheidungssituation reduziert. Es wird aber auch deutlich, dass mit diesem Instrument kein Verfahren vorliegt, dessen Einsatz automatisch zu einer eindeutigen Rangfolge führt. Es bleibt notwendig, die Anwendung der Hassediagrammtechnik in einen umfassen deren Entscheidungs-und Zielfindungsprozess zu integrieren.

Diskussion

Die Sortierung erfolgt bewertend, d.h. sie nutzt aus, dass charakteristischen Eigenschaften von Bergwerken inhärent eine Orientierung nach ?gut’ und ?schlecht’, zugeordnet werden kann. Es wird aber auch deutlich, dass mit diesem Instrument kein Verfahren vorliegt, dessen Einsatz, automatisch zu einer eindeutigen Rangfolge führt.

Schlussfolgerungen

Es bleibt notwendig, die Anwendung der Hassediagrammtechnik in einen umfassenderen Entscheidungs- und Zielfindungsprozess zu integrieren. Vorschläge zu einer Erweiterung der Hassediagrammtechnik werden formuliert.

Empfehlungen und Perspektiven

Die Hassediagrammtechnik versteht sich als eine Bewertungsmethodik, die das in der Nachhaltigkeits-/Bewertungsdiskussion so gefürchtete Vergleichen von ?Äpfeln mit Birnen’ vermeidet. Als relativ neue Methode, die sich als Alternative zu etablierten Bewertungsverfahren sieht, lässt sich weiterer Forschungsbedan ableiten.     

Holy Cows: A Look at the Influence of Religious Beliefs on Dairy Animal Welfare on Kibbutzim in Israel

The influence of religious beliefs on people's attitudes andactions in the area of animal welfare was examined by interviewing dairyworkers on kibbutzim (communal agricultural settlements) in Israel.Workers on religiously observant kibbutzim were no more consistent intheir attitudes toward and treatment of dairy cows than workers onnon-observant and selectively observant kibbutzim.     

Water and sectoral policies in agriculture–forest frontiers: An expanded interdisciplinary research approach

Major land use changes such as deforestation and restoration influence water resources in agriculture–forest landscapes. Changes are observed in water flows, groundwater infiltration, water quality and rainfall. Interdisciplinary water–forest research has unravelled biophysical parts of the interplay that influences forest and water resources. In this Perspective paper, we propose an expanded interdisciplinary research approach to study water and policies in agriculture–forest frontiers. The approach differs in four important aspects from previous ones: (i) a conceptual ‘frontier’ understanding; an analytical focus on (ii) agriculture and (iii) policy–water linkages; (iv) empirical attention to northern and southern countries. The approach is put into practice with the “Pendulum” framework, with interventions and the agriculture–forest frontier oscillating over time between exploitation and restoration. Through the approach, a better understanding will be provided on the dynamic interplay of water and policies in oscillating agriculture–forest frontiers, with changing outcomes for people and environment.     

A Comparison of Biomonitoring Methods for the Estimation of Atmospheric Pollutants in an Industrial Town in Austria

In the period between 1999 and 2000 epiphytic bryophytes were taken as bioindicators for air pollution by use of the IAP method (Index of Atmospheric Purity) and the VDI method within the Association of Engineers standards list (adapted from guideline 3799, 1995) in the heavy industrialized town of Linz, Austria. 52 study sites (265 trees) were analysed regarding species richness, coverage, and vitality. Q-values (sensitivity factors), calculated for each species showed significant differences for the various host tree species. The results gained by the IAP and the VDI methods were diverse, regarding the various sites where only 25% were classified identical. These differences can mainly be attributed to the differing host tree species and the size of the recording area on the various trees. Clusters of similar pollution levels were calculated and drawn as maps for both methods tested. Comparing the results of the IAP and the VDI methods with data derived from technical measurements (SO₂, NO, NO₂, and dust) a correlation between IAP-indices and SO₂ concentrations could be observed. No correlation was detected between the results derived from VDI recording and for NO, NO₂, and dust.     

Laboratory and field comparison of measurements obtained using the available diffusive samplers for ozone and nitrogen dioxide in ambient air

This study presents an evaluation of the extent of differences between measurements performed by O(3) and NO(2) diffusive samplers and by the reference methods for diffusive samplers commercially available. The tests were performed in an exposure chamber under extreme conditions of controlling factors and under field conditions. For NO(2), the results of the laboratory experiments showed that most of the diffusive samplers were affected by extreme exposure conditions. The agreement between the samplers and the reference method was better for the field tests than for the laboratory ones. The estimate of the uptake rate for the exposure conditions using a model equation improved the agreement between the diffusive samplers and the reference methods. The agreement between O(3) measured by the diffusive samplers and by the reference method was satisfactory for 1-week exposure. For 8-hour exposures, the diffusive samplers with high uptake rates quantified better the O(3) concentration than the samplers with low uptake rates. As for NO(2), the results of the O(3) field tests were in better agreement with the reference method than the ones of the laboratory tests. The field tests showed that the majority of diffusive samplers fulfils the 25% uncertainty requirement of the NO(2) European Directive and the 30% uncertainty requirement of the O(3) European Directive for 1-week exposure.     

Transcriptional profiles induced by the Aryl Hydrocarbon Receptor agonists 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,7,8-pentachlorodibenzofuran in primary rat hepatocytes

Toxicogenomics was used to examine mRNA expression profiles obtained from primary rat hepatocytes treated for 24 h with 0.01 or 1.0 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 0.02 or 2.0 nM 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF) and 0.1 or 10 nM 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF). The concentrations of 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF were chosen to be equivalent to 2,3,7,8-TCDD’s concentration based on the toxic equivalency factor/toxic equivalent (TEF/TEQ) method for estimating biological potency. 2,3,7,8-TCDD at 1.0 nM altered the expression of 533 genes; 2,3,4,7,8-PeCDF at 2.0 nM altered 182 genes, and 2,3,7,8-TCDF at 10 nM altered 154 genes. Of these, 57 genes were affected by all three congeners. Agglomerative hierarchical clustering revealed distinct congener-dependent gene subclusters. Principal components analyses of the microarray data revealed that these congeners cluster independently of one another. Data presented here demonstrate that equivalent TEQ concentrations of 2,3,7,8-TCDD, 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF, while altering the expression of a small battery of genes in common, also produce substantial congener specific alterations in gene expression.     

Orchard management under the effects of climate change: implications for apple,plum, and almond growing

Environmental Science and Pollution Research - The authors analyzed certain species and varieties of fruit tree in which applied crop technology is used and also undergoes the effects of climate...     

Medical radioisotopes in the environment – following the pathway from patient to river sediment

Motivated by the detection of ¹³¹I in river sediment in routine long-term surveillance samples, a systematic short-term study of the wastewater treatment chain was planned and conducted. Inflow, effluent and primary sludge were collected on a daily basis during two weeks at a regional wastewater treatment plant. Samples were investigated by gamma spectroscopy. Four medically used isotopes could be identified (¹³¹I and ^99mTc regularly, ¹⁵³Sm and ¹²³I sporadically). The concentration levels coincide well with literature data for ¹³¹I, and with our own long-term data for ¹³¹I and ^99mTc for the same plant. Cosmogenic ⁷Be activity in primary sludge correlated well with rainfall intensity. Surface sediment was sampled at low tide at both shores of the river, up- and downstream of the plant. ¹³¹I was identified in all samples, with a sharp maximum (about 100 Bq kg⁻¹ d.m.) at the discharge point of the plant and lower levels elsewhere, decreasing monotonically in downstream direction. ⁷Be and ¹³⁷Cs showed the same behaviour, but no peak at the discharge point. Predictions from simple equilibrium models for the transport and sedimentation of ¹³¹I show good agreement with the experimental data and suggest that the wastewater treatment plant is the main source for this isotope.