Changes in sea level may be attributed either to barotropic (involving the entire water column) or baroclinic processes (governed by stratification). It has been widely accepted that barotropic sea level changes in the tropics are insignificant at intraseasonal time scales (periods of 30-80 days). Based on bottom pressure records, we present evidence for significant basin-wide barotropic sea level variability in the tropical Indian Ocean during December-April with standard deviations amounting to ∼30-60% of the standard deviation in total intraseasonal sea level variability. The origin of this variability is linked to a small patch of wind over the Eastern Indian Ocean, associated with boreal winter Madden-Julian Oscillations (MJO). These large fluctuations are likely to play a prominent role in the intraseasonal sea level and mass budgets. Because of their much faster propagation than baroclinic processes, they allow the basin to adjust to climatic perturbations much more rapidly than was previously thought.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6425029 | PMC |
http://dx.doi.org/10.1038/s41467-019-09243-5 | DOI Listing |
Mar Pollut Bull
December 2024
Department of Biology and Wildlife, University of Alaska Fairbanks, 2090 Koyukuk Dr, Fairbanks, AK 99775, USA; Institute of Arctic Biology, University of Alaska Fairbanks, 2140 Koyukuk Dr, Fairbank, AK 99775, USA.
Several wildlife species exhibit marked spatial variation in toxicologically relevant tissue concentrations of mercury across the Aleutian Islands of Alaska, most notably the endangered Steller sea lion (Eumetopias jubatus). To unravel potential environmental and trophic pathways driving mercury variation in this species of concern, we investigated spatiotemporal and ecological patterns in total mercury concentrations and stable isotope ratios of carbon and nitrogen from muscle tissues of twelve mid-trophic level prey species of the region (n = 1461). Dividing samples into island groups explained biogeochemical variation better than larger spatial resolutions, with Amchitka Pass and Buldir Pass acting as strong geographic break points.
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December 2024
Department of Integrative Biology, Oregon State University, Corvallis, OR, 97331, USA.
The supply of nitrogen (N) and the efficiency with which it is used by phytoplankton serve as two fundamental controls on the productivity of many marine ecosystems. Shifts in nitrogen use efficiency (NUE) can decouple primary production from N-supply but how NUE varies across systems is poorly known. Through a global synthesis of how total N (TN) is apportioned among phytoplankton, particulate, dissolved inorganic, and dissolved organic pools, we demonstrate that NUE underlies broad variations in primary production.
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December 2024
Soil and Water Management & Crop Nutrition Laboratory, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna, Austria.
The Northern Antarctic Peninsula (NAP) and the West Antarctic Ice Sheet (WAIS) are likely to respond rapidly to climate changes by increasing the collapse of peripheral ice shelves and the number of days above 0 °C. These facts make this region a representative hotspot of the global sea level rise and the location of one of the global climate tipping points (thresholds in the Earth system whose changes may become irreversible, if exceeded). Understanding the climate evolution of the NAP, based on past evidences, may help infer its future scenario.
View Article and Find Full Text PDFNeotrop Entomol
December 2024
Escuela de Agronomía, Filial Oxapampa, Univ Nacional Daniel Alcides Carrión, Oxapampa, Pasco, Peru.
Fruit flies (Diptera: Tephritidae) are significant pests of fruit and vegetable crops worldwide. Despite their importance, some regions in South America remain under-researched regarding the fruit fly species that damage host plants and the parasitoids that provide their natural control. In this study, we investigated the interactions among host plants, fruit flies, and their larval parasitoids along two altitudinal gradients in Oxapampa, Pasco, a tropical Andean forest in Peru.
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December 2024
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, C1A 4P3, Canada.
Monitoring mortality is an essential strategy for fish health management. Commercial marine finfish sites in British Columbia, Canada, are required to report mortality events (MEs) to Fisheries and Oceans Canada (DFO), which makes these data publicly available. This study aimed to analyze the spatial and temporal patterns of ME composition and total MEs.
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