Environmental DNA, hydrochemistry and stable water isotopes as integrative tracers of urban ecohydrology

Urbanization and the persistent environmental changes present a major challenge for urban freshwaters and availability of water for humans and wildlife. In order to increase understanding of urban ecohydrology, we investigated the variability of planktonic bacteria and benthic diatoms - as two key biological indicators - coupled with insights from hydrochemistry and stable water isotopes across four urban streams characterized by different dominant water sources in Berlin, the German capital, over a period of one year (2021-2022). DNA metabarcoding results show that substantial spatio-temporal variability exists across urban streams in terms of microbial diversity and richness, with clear links to abiotic factors and nutrient concentrations. Bacterial communities showed clear distinction between effluent-impacted and non-effluent impacted streams as well as clear seasonal turnover. In-stream benthic diatom assemblages also showed robust seasonal variation as well as high species diversity. Our multiple-tracer approach is relevant for emerging questions regarding the increased use of treated effluent to supplement declining baseflows, the assessment of stream restoration projects and the impact of storm drainage and surface pollution on aquatic ecosystem health. eDNA analysis allows analysis of spatial and temporal patterns not feasibly studied with traditional analyses of macroinvertebrates. This can ultimately be leveraged for future water resource management and restoration planning and monitoring of urban freshwater systems across metropolitan areas.

Supraclavicular glomus tumor, 20 year history of undiagnosed shoulder pain: a case report

A long-standing case of severe dysesthesia due to a supraclavicular glomus tumor is presented. Chronic pain caused by a subcutaneous glomus (non-chemodectoma) tumor is rare and usually misdiagnosed. The supraclavicular location, presentation, and coincidence of trauma history are unique in this case. A 62-year-old male complained of 20 years of intractable right shoulder and supraclavicular region pain, which started 6 months after a fall. The pain was unrelieved by repeated and extensive physical therapy, chiropractic manipulation, local steroid injections, and two shoulder operations. The cause of the condition remained undiagnosed and obscure. Local surgical exploration revealed a subcutaneous grayish mass with pathologically proven glomus tumor. Immediate alleviation of the pain and tenderness followed complete resection of the mass. The patient remained free of pain at a 2-year follow-up. Subcutaneous glomus (non-chemodectoma) tumors can occur in unusual sites, and should be considered in chronic regional pain syndromes. Immediate cure is generally achieved by local resection. Pertinent literature is reviewed.