Southern Ocean primary productivity is principally controlled by adjustments in light and iron limitation, but the spatial and temporal determinants of iron availability, accessibility, and demand are poorly constrained, which hinders accurate long-term projections. We present a multidecadal record of phytoplankton photophysiology between 1996 and 2022 from historical in situ datasets collected by Biogeochemical Argo (BGC-Argo) floats and ship-based platforms. We find a significant multidecadal trend in irradiance-normalized nonphotochemical quenching due to increasing iron stress, with concomitant declines in regional net primary production. The observed trend of increasing iron stress results from changing Southern Ocean mixed-layer physics as well as complex biological and chemical feedback that is indicative of important ongoing changes to the Southern Ocean carbon cycle.
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http://dx.doi.org/10.1126/science.abl5237 | DOI Listing |
Conserv Biol
January 2025
Marine Mammal Research Program, Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, Hawai'i, USA.
Several legal acts mandate that management agencies regularly assess biological populations. For species with distinct markings, these assessments can be conducted noninvasively via capture-recapture and photographic identification (photo-ID), which involves processing considerable quantities of photographic data. To ease this burden, agencies increasingly rely on automated identification (ID) algorithms.
View Article and Find Full Text PDFSci Total Environ
January 2025
Aquatic Health Program, UC Davis, 1 Shields Ave, Davis, CA 95616, USA.
Health and nutrition of individuals are tied to reproductive success, which determines population viability. Environmental variability and anthropogenic effects can affect the health and nutrition of a species leading to reproductive repercussions which can hinder recovery of endangered populations. Indices of health and nutrition were examined for an imperiled species, delta smelt, Hypomesus transpacificus, in relation to their reproductive status to evaluate the effects of hydrologic conditions in the San Francisco Estuary and Sacramento-San Joaquin Delta.
View Article and Find Full Text PDFEcol Evol
January 2025
Minderoo Foundation Perth Western Australia Australia.
Coral reefs worldwide are threatened by increasing ocean temperatures because of the sensitivity of the coral-algal symbiosis to thermal stress. Reef-building corals form symbiotic relationships with dinoflagellates (family Symbiodiniaceae), including those species which acquire their initial symbiont complement predominately from their parents. Changes in the composition of symbiont communities, through the mechanisms of symbiont shuffling or switching, can modulate the host's thermal limits.
View Article and Find Full Text PDFMethodsX
June 2025
Department of Royal Rainmaking and Agricultural Aviation, Bangkok 10900, Thailand.
Rainfall prediction is a crucial aspect of climate science, particularly in monsoon-influenced regions where accurate forecasts are essential. This study evaluates rainfall prediction models in the Eastern Thailand by examining an optimal lag time associated with the Oceanic Niño Index (ONI). Five deep learning models-RNN with ReLU, LSTM, GRU (single-layer), LSTM+LSTM, and LSTM+GRU (multi-layer)-were compared using mean absolute error (MAE) and root mean square error (RMSE).
View Article and Find Full Text PDFSci Rep
January 2025
College of Ocean and Meteorology & South China Sea Institute of Marine Meteorology, Guangdong Ocean University, 524088, Zhanjiang, Guangdong, China.
Accurate classification of tropical cyclone (TC) tracks is essential for evaluating and mitigating the potential disaster risks associated with TCs. In this study, three commonly used methods (K-means, Fuzzy C-Means, and Self-Organizing Maps) are assessed for clustering historical TC tracks that originated in the South China Sea from 1949 to 2023. The results show that the K-means method performs the best, while the Fuzzy C-Means and Self-Organizing Maps methods are also viable alternatives.
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