Calibration of tracer concentration measurement and results

A reliable assessment of relevant substance flows is very important for environmental risk assessments and efficiency analysis of measures to reduce or avoid emissions of micropollutants like drugs to water systems. Accordingly, a detailed preparation of monitoring campaigns should include an accuracy check for the sampling configuration to prove the reliability of the monitoring results and the subsequent data processing. The accuracy of substance flow analyses is expected to be particularly weak for substances having high short-term variations of concentrations in sewage. This is especially the case linked to the observation of substance flows close to source in waste water systems. The verification of a monitoring configuration in a hospital sewer in Luxembourg is in the centre of interest of the case study presented here. A tracer test in the sewer system under observation is an essential element of the suggested accuracy check and provides valuable information for an uncertainty analysis. The results illustrate the importance of accuracy checks as an essential element of the preparation of monitoring campaigns. Moreover the study shows that continuous flow proportional sampling enables a representative observation of short-term peak loads of the iodinated x-ray contrast media iobitridol close to source.

Physical properties and AMS characteristics of ODP Site 185-1149 sediments

During Ocean Drilling Program Leg 185, we studied progressive changes of microfabrics of unconsolidated pelagic and hemipelagic sediments in Holes 1149A and 1149B in the northwest Pacific at 5818 m water depth. We paid particular attention to the early consolidation and diagenetic processes without tectonic deformation before the Pacific plate subduction at the Izu-Bonin Trench. Shape, size, and arrangement of pores were analyzed by scanning electron microscope (SEM) and were compared to anisotropy of magnetic susceptibility (AMS) data. The microfabric in Unit I is nondirectional fabric and is characterized by large peds of ~10-100 µm diameter, which are made up of clay platelets (mainly illite) and siliceous biogenic fragments. They are ovoid in shape and are mechanically packed by benthic animals. Porosity decreases from 0 to 60 meters below seafloor (mbsf) in Unit I (from 60% to 50%) in association with macropore size decreases. The microfabric of coarser grain particles other than clay in Unit II is characterized by horizontal preferred orientation because of depositional processes in Subunit IIA and burial compaction in Subunit IIB. On the other hand, small peds, which are probably made of fragments of fecal pellets and are composed of smectite and illite (3-30 µm diameter), are characterized by random orientation of clay platelets. The clay platelets in the small peds in Subunit IIA are in low-angle edge-to-face (EF) or face-to-face (FF) contact. These peds are electrostatically connected by long-chained clay platelets, which are interconnected by high-angle EF contact. Breaking of these long chains by overburden pressure diminishes the macropores, and the clay platelets in the peds become FF in contact, resulting in decreases in the volume of the micropores between clay platelets. Thus, porosity in Subunits IIA and IIB decreases remarkably downward. The AMS indicates random fabric and horizontal preferred orientation fabric in Units I and II, respectively. This result corresponds to that of SEM microfabric observations.In Subunit IIB, pressure solutions around radiolarian tests and clinoptilolite veins with normal displacement sense are seen distinctively below ~170 mbsf, probably in correspondence to the transition zone from opal-A to opal-CT.

Physiological responses and scope for growth upon medium-term exposure to the combined effects of ocean acidification and temperature in a subtidal scavenger Nassarius conoidalis

Physiological responses (ingestion rate, absorption rate and efficiency, respiration, rate, excretion rate) and scope for growth of a subtidal scavenging gastropod Nassarius conoidalis under the combined effects of ocean acidification (pCO2 levels: 380, 950, 1250 µatm) and temperature (15, 30 °C) were investigated for 31 days. There was a significant reduction in all the physiological rates and scope for growth following short-term exposure (1-3 days) to elevated pCO2 except absorption efficiency at 15 °C and 30 °C, and respiration rate and excretion rate at 15 °C. The percentage change in the physiological rates ranged from 0% to 90% at 15 °C and from 0% to 73% at 30 °C when pCO2 was increased from 380 µatm to 1250 µatm. The effect of pCO2 on the physiological rates was enhanced at high temperature for ingestion, absorption, respiration and excretion. When the exposure period was extended to 31 days, the effect of pCO2 was significant on the ingestion rate only. All the physiological rates remained unchanged when temperature increased from 24 °C to 30 °C but the rates at 15 °C were significantly lower, irrespective of the duration of exposure. Our data suggested that a medium-term exposure to ocean acidification has no effect on the energetics of N. conoidalis. Nevertheless, the situation may be complicated by a longer term of exposure and/or a reduction in salinity in a warming world.

Ensemble prediction distribution maps of macroalgae for current conditions and four climate change scenarios and high resultion bathymetry for Potter Cove, WAP, Antarctica

Species distribution models (SDM) predict species occurrence based on statistical relationships with environmental conditions. The R-package biomod2 which includes 10 different SDM techniques and 10 different evaluation methods was used in this study. Macroalgae are the main biomass producers in Potter Cove, King George Island (Isla 25 de Mayo), Antarctica, and they are sensitive to climate change factors such as suspended particulate matter (SPM). Macroalgae presence and absence data were used to test SDMs suitability and, simultaneously, to assess the environmental response of macroalgae as well as to model four scenarios of distribution shifts by varying SPM conditions due to climate change. According to the averaged evaluation scores of Relative Operating Characteristics (ROC) and True scale statistics (TSS) by models, those methods based on a multitude of decision trees such as Random Forest and Classification Tree Analysis, reached the highest predictive power followed by generalized boosted models (GBM) and maximum-entropy approaches (Maxent). The final ensemble model used 135 of 200 calculated models (TSS > 0.7) and identified hard substrate and SPM as the most influencing parameters followed by distance to glacier, total organic carbon (TOC), bathymetry and slope. The climate change scenarios show an invasive reaction of the macroalgae in case of less SPM and a retreat of the macroalgae in case of higher assumed SPM values.