Hotbeds of Biogeochemical Diversity: Insights from Urban Long-Term Ecological Research Sites

Over the last two decades, long-term ecological research in the United States has expanded to urban sites. Cities, despite the dominance of built structures, utilize unexpected amounts of human-generated nutrients. Additionally, cities can both intensify and weaken local impacts of processes such as climate. Challenges remain at these sites, as property-scale biogeochemical forcings from individuals and institutions must be accounted for throughout this research. Meeting the challenge is crucial as prediction of biogeochemical processes is fundamental to the development of sustainable strategies for managing human inputs to cities and surrounding areas.

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December 2025 --The Variscan Orogeny in Europe – Understanding Supercontinent Formation

The Variscan orogen formed between 380 and 300 million years ago through several accretionary and collisional cycles, culminating with the construction of the Pangea supercontinent. This process occurred via sequential opening and closure of oceanic basins, synchronous detachment of Gondwana derived continental ribbons, and their outboard amalgamation onto the Laurussia margin. The Variscan orogen is rather unique compared with other orogenic belts on Earth: its overthickened and dominantly magmatic crust in the central belt, surprisingly minor mantle involvement in the magmatic and geodynamic processes, coherent and pulsed magmatism along the collision suture, and its complex accretionary history. Because its final product, Pangea, is the youngest and best-understood supercontinent on Earth, the Variscan orogeny offers clues for understanding the mechanisms of supercontinent formation.