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Climate change is altering global ocean phenology, the timing of annually occurring biological events. We examined the changing phenology of the phytoplankton accumulation season west of the Antarctic Peninsula to show that blooms are shifting later in the season over time in ice-associated waters. The timing of the start date and peak date of the phytoplankton accumulation season occurred later over time from 1997 to 2022 in the marginal ice zone and over the continental shelf. A divergence was seen between offshore waters and ice-associated waters, with offshore bloom timing becoming earlier, yet marginal ice zone and continental shelf bloom timing shifting later. Higher chlorophylla(chla) concentration in the fall season was seen in recent years, especially over the northern continental shelf. Minimal long-term trends in annual chlaoccurred, likely due to the combination of later start dates in spring and higher chlain fall. Increasing spring wind speed is the most likely mechanism for later spring start dates, leading to deeper wind mixing in a region experiencing sea ice loss. Later phytoplankton bloom timing over the marginal ice zone and continental shelf will have consequences for surface ocean carbon uptake, food web dynamics, and trophic cascades.
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Peak Runoff Timing Is Linked to Global Warming Trajectories
Abstract The earth's hydroclimate is continuing to change, and the corresponding impacts on water resource space‐time distribution need to be understood to mitigate their socioeconomic consequences. A variety of ecosystem services, transport processes, and human activities are synced with thetimingof peak annual runoff. To understand the influence of changing hydroclimate on peak runoff dates across the continental United States, we downscaled outputs of 10 Global Circulation Models for different future scenarios. Our results quantify robust spatial patterns of both negative (up to 3–5 weeks) and positive (up to 2–4 weeks) shifts in the dates of peak annual runoff occurrence by the end of this century. In snowmelt‐dominated areas, annual maxima are projected to shift to earlier dates due to the corresponding changes in snow accumulation timing. For regions in which the occurrence of springtime extreme soil wetness shifts to later time, we find that peak annual runoff is also projected to be delayed. These patterns of runoff timing change tend to be more pronounced for projections of higher greenhouse concentration in the future.
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- PAR ID:
- 10449435
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Earth's Future
- Volume:
- 9
- Issue:
- 8
- ISSN:
- 2328-4277
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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