Rapid Consumption of Dihydrogen Injected into a Shallow Aquifer by Ecophysiologically Different Microbes

The envisaged future dihydrogen (H2) economy requires a H2 gas grid as well as large deep underground stores. However, the consequences of an unintended spread of H2 through leaky pipes, wells, or subterranean gas migrations on groundwater resources and their ecosystems are poorly understood. Therefore, we emulated a short-term leakage incident by injecting gaseous H2 into a shallow aquifer at the TestUM test site and monitored the subsequent biogeochemical processes in the groundwater system. At elevated H2 concentrations, an increase in acetate concentrations and a decrease in microbial α-diversity with a concomitant change in microbial β-diversity were observed. Additionally, microbial H2 oxidation was indicated by temporally higher abundances of taxa known for aerobic or anaerobic H2 oxidation. After H2 concentrations diminished below the detection limit, α- and β-diversity approached baseline values. In summary, the emulated H2 leakage resulted in a temporally limited change of the groundwater microbiome and associated geochemical conditions due to the intermediate growth of H2 consumers. The results confirm the general assumption that H2, being an excellent energy and electron source for many microorganisms, is quickly microbiologically consumed in the environment after a leakage.

Predictability of initial hydrogeochemical effects induced by short-term infiltration of ∼75 °C hot water into a shallow glaciogenic aquifer

Despite their potential in heating supply systems, thus far high-temperature aquifer thermal energy storages (HT-ATES) currently lack widespread application. Reducing the potential risks by improving the predictability of hydrogeochemical processes accelerated or initiated at elevated temperatures might promote the development of this technology. Therefore, we report the results of a short-term hot water infiltration field test with subsurface temperatures above 70 °C, along with associated laboratory batch tests at 10, 40 and 70 °C for 28 sediment samples to determine their usability for geochemical prediction. Most groundwater components had lower maximal concentrations and smaller concentration ranges in field samples compared to the batch tests. This indicates that the strongest geochemical effects observed in laboratory tests with sufficient site-specific sediment samples will likely be attenuated at the field scale. A comparison of field measurements with predicted concentration ranges, based on temperature induced relative concentration changes from the batch tests, revealed that the predictive power was greatest, where the hot infiltrated water had cooled least and the strongest geochemical effects occurred. The batch test-based predictions showed the best accordance with field data for components, with significant temperature-induced concentration changes related to ion exchange and (de)sorption processes. However, accurate prediction of concentration changes based on other processes, e.g. mineral dissolution, and downstream reversals in concentrations, requires further investigation. The here presented procedure enables the prediction of maximal expectable temperature-dependant concentration changes for most environmentally relevant ancillary groundwater components, e.g. As, with limited effort.

Monitoring of the effects of a temporally limited heat stress on microbial communities in a shallow aquifer

Aquifer thermal energy storage (ATES) is a key concept for the use of renewable energy resources. Interest in ATES performed at high temperature (HT-ATES; > 60 °C) is increasing due to higher energetic efficiencies. HT-ATES induces temperature fluctuations that exceed the natural variability in shallow aquifers, which could lead to adverse effects in subsurface ecosystems by altering the groundwater chemistry, biodiversity, and microbial metabolic activity, resulting in changes of the groundwater quality, biogeochemical processes, and ecosystem functions. The aim of this study was to emulate the initial operating phase of a HT-ATES system with a short-term infiltration of warm water into Pleistocene sandur sediment and, consequently, to monitor the thermal effects on the groundwater microbiome inhabiting an imitated affected space of an HT-ATES system. Therefore, local groundwater was withdrawn, heated up to 75 °C, and re-infiltrated into a shallow aquifer located near Wittstock/Dosse (Brandenburg, Germany) for around five days. Groundwater samples taken regularly before and after the infiltration were analyzed by 16S rRNA gene amplicon sequencing for microbial diversity analyses as well as total cell counting. During the infiltration, a thermal plume with groundwater temperatures increasing from 9 ± 2 to up to ~65 °C was recorded. The highest temperature at which groundwater samples were taken was 34.9 °C, a temperature typically arising in the affected space of an HT-ATES system. The microbial communities in the groundwater were mainly composed of Gammaproteobacteria, Alphaproteobacteria, Bacteroidia, and Actinobacteria, and the total cell numbers ranged from 3.2 * 10⁴ to 3.1 * 10⁶ cells ml^-1. Neither the compositions of the microbial communities nor the total number of cells in groundwater were significantly changed upon moderate temperature increase, indicating that the diverse groundwater microbiome was resilient to the temporally limited heat stress.

Data of a high temperature heat injection test

This document compiles the data related to a high temperature heat injection test, which was carried out at an injection temperature of 74 °C in a shallow aquifer and is presented by Heldt et al. [1]. The data set contains transient measurements of temperatures at 18 wells in 10 depths and measurements of the experimental boundary conditions (injection temperature and flow rate) at a temporal resolution of up to 1 min. The spatial configuration and the technical details about where and how the data have been measured are provided. In addition, data of a multilevel multi well pumping test are shown. The presented data is useful to gain insights into the thermohydraulic processes induced by a high temperature heat injection test and can furthermore be used for the development and verification of numerical models of the presented experiment and similar applications like high temperature aquifer thermal energy storage.

Temperature influence on mobilisation and (re)fixation of trace elements and heavy metals in column tests with aquifer sediments from 10 to 70 °C

The operation of seasonal underground thermal energy storages (UTES) as part of renewed heat supply systems can cause amplified temperature variations in the urban subsurface. Therefore, long-term environmental consequences for water extractions by trace elements and heavy metals (TEHMs) are a key point of concern regarding temperature effects on aquifer hydrogeochemistry. To address this issue, we report the results of flow-through and circular-flow column tests conducted with 4 anoxic northern German aquifer sediments, tempered to 10, 25, 40 and 70 °C and analysed for 20 TEHMs. Increased temperatures in column tests caused increasing Li, As, Mo, Sb and Ba concentrations and decreasing Ni concentrations in all of the sediments with a sediment-specific extent, whereas effects on V, Mn, Co, Tl and U concentrations varied sediment-specifically. Apart from Ba, all these components were released as a pulse in the initial heating phase, indicating a temperature dependent, finite, elutable pool. Re-cooling of the previously heated circular-flow column tests to 10 °C caused reversals of concentration changes by 30-95%. This indicates a return to initial hydrochemical conditions after termination of heat storage operation and downstream from heat storages during the operations. The latter was approximated for As with a simplified analytical 1-dimensional approach, presuming transferability from a laboratory to a field scale. This reversal in concentration changes enables active cooling as a countermeasure in cases of unexpected, adverse TEHM progression. From the perspective of our findings, TEHM concentration changes appear to be temporally and spatially limited.

[Changes in the amount of myosin and the rate of myosin biosynthesis in vascular cells in culture]

The relative myosin content of aortic cells of newborn rats was estimated cytophotometrically in the course of cultivation using indirect immunofluorescence staining. It should be shown that the average myosin content of the cell population and the number of cells with high myosin content is greatly enhanced when confluency of the cells is reached and proliferation stops. Following the amount of 14C-labelled leucine incorporated in immunoprecipitated myosin during the same period we found that increasing myosin content of the cells results from an enhanced rate of myosin biosynthesis.

[Surgical treatment of anastomosis ulcers. 1. Short-term results]

Records of 151 patients from the years 1964--1979 with anastomotic ulcers including relapses of ulcers after vagotomy reveal a total lethality of 3.3 per cent after reoperation. Re-gastrectomy with or without additional vagotomy shows a lethality of 5.7 per cent. If vagotomy alone is carried out there were no lethality and nearly no serious complications. Gastrectomy because of recurrent peptic ulcer after primary vagotomy has also no lethality. With regard to less serious postoperative complications including lethality after vagotomy instead of re-gastrectomy we should favour vagotomy for re-operation. Our further examinations will show whether this attitude is justified by long-term results after re-operation of the stomach in consequence of recurrent pepti ulcer.

[Outpatient breast surgery]

Indication, standard operative procedure and technique of ambulant diagnostic mammary surgery is shown in detail from 15 years of experience. In respect of reducing costs intraoperative quick-frozen sections and in case of malignancy radical mastectomy immediately after biopsy during continuous general anesthesia is important. By retrospective analysis we could prove that operative results in treatment of benign breast tumors by out-patient surgery or otherwise for in-patients do not differ. According to an inquiry patients preferred by 60% out-patient procedure.

[Surgical treatment of ulcer]

The standard of today in surgical treatment of the duodenal and gastric ulcer in Germany is shown. Positive and negative aspects of the different methods are discussed. Special technics are recommended for the different types of gastroduodenal ulcera.

[Surgical treatment of gastric stump carcinoma. Causes of the poorer results compared with primary gastric carcinoma (author's transl)]

In 3183 gastric operations during the past 13 1/4 years, 40 gastric stump carcinomas were observed after B II resection for benign ulcer. Eight of these underwent radical subtotal resection; 14 had total gastrectomy. Early and late follow-up prognosis of total gastrectomy for gastric stump carcinoma is significantly (p less than 0,05) worse than that for total gastrectomy for primary carcinoma of the stomach (n = 112). To improve the prognosis of gastric stump carcinoma, periodic follow-up of all patients with resected stomach to confirm an early diagnosis is necessary. Radical subtotal resection must be given priority because of its significantly lower lethality compared with a total gastrectomy.