Showing papers by "Michael N. Gooseff published in 2019"
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University of California, Davis1, Pennsylvania State University2, Aarhus University3, University of Oxford4, University of Lapland5, Institute of Arctic and Alpine Research6, Dartmouth College7, Johns Hopkins University Applied Physics Laboratory8, Umeå University9, University College London10, Harvard University11, Joint Institute for the Study of the Atmosphere and Ocean12, National Oceanic and Atmospheric Administration13
TL;DR: Expected consequences of increased Arctic warming include ongoing loss of land and sea ice, threats to wildlife and traditional human livelihoods, increased methane emissions, and extreme weather at lower latitudes.
Abstract: Over the past decade, the Arctic has warmed by 0.75°C, far outpacing the global average, while Antarctic temperatures have remained comparatively stable. As Earth approaches 2°C warming, the Arctic and Antarctic may reach 4°C and 2°C mean annual warming, and 7°C and 3°C winter warming, respectively. Expected consequences of increased Arctic warming include ongoing loss of land and sea ice, threats to wildlife and traditional human livelihoods, increased methane emissions, and extreme weather at lower latitudes. With low biodiversity, Antarctic ecosystems may be vulnerable to state shifts and species invasions. Land ice loss in both regions will contribute substantially to global sea level rise, with up to 3 m rise possible if certain thresholds are crossed. Mitigation efforts can slow or reduce warming, but without them northern high latitude warming may accelerate in the next two to four decades. International cooperation will be crucial to foreseeing and adapting to expected changes.
285 citations
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TL;DR: In this paper, the authors applied nutrient spiraling theory to simultaneously measure reaction and transport of ammonium (NH4+) and phosphate (PO43−), nutrients limiting primary productivity in Arctic ecosystems.
Abstract: Hydrologic flowpaths might propagate biogeochemical signals among connected ecosystems or alter and dampen signals because of reactions or retention occurring during transport. In the Arctic, experimentally warmed terrestrial tundra releases inorganic nitrogen (N), but the fate of this newly released N remains unclear. Nitrogen could be passively transported downslope in flowing water, or retained when flowpaths intercept N-limited ecosystems. We applied nutrient spiraling theory to simultaneously measure reaction and transport of ammonium (NH4+) and phosphate (PO43−), nutrients limiting primary productivity in Arctic ecosystems. Pulse fertilization experiments were focused on flowpaths known as water tracks that hydrologically connect soils to receiving streams and lakes in upland tundra of Alaska. Water tracks typically retained PO43−, but passively transported NH4+, thus potentially propagating NH4+ produced by warming tundra soils to downstream ecosystems. Nutrient uptake was uncorrelated with the relative proportion of downslope transport in transient storage zones, but greater NH4+ uptake occurred as advective hydrologic flux increased relative to dispersion. Phosphate uptake declined as thaw depth increased over the summer season likely because of declining capacity for biotic uptake or sorption in deeper soils. Phosphorus limitation in fluvial ecosystems of the Arctic might result in efficient transport of inorganic N to N-limited lentic and coastal ecosystems, where increasing subsidies furnished by N loss from warming terrestrial tundra could support enhanced primary production.
22 citations
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19 citations
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6 citations