Evolution of marine heatwaves in warming seas: the Mediterranean Sea case study

Frontiers in Marine Science, Journal Year: 2023, Volume and Issue: 10

Published: June 30, 2023

Anomalous warming of the upper ocean is increasingly being observed in Mediterranean Sea. Extreme events, known as marine heatwaves (MHWs), can have a profound impact on ecosystems, and their correct detection characterization are crucial to define future scenarios. Here, we analyze MHWs over last 41 years (1982–2022) sea surface temperatures (SSTs). We show that intensification frequency, intensity, duration recent mainly due shift SST mean occurred two decades largely reduced when analyzing detrended data. Detrending thus allows use fixed climatology without overestimating MHW properties time distinguishes long-term (i.e., trend) from transient abrupt changes. Analogous results also found shorter temporal period, by 13 (2007–2020) situ data collected at different depths (5 40 m) Columbretes Islands. Additionally, analysis reveals atmospheric summer could affect layer 10 m depth. Lastly, catalogue major since 1982 presented. This evidences an exceptionally long-lasting intense MHW, starting May 2022 persisting, least, until end year, resulting event with highest cumulative intensity just after well-known 2003 event.

Language: Английский

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Marine heatwaves on the rise: One of the strongest ever observed mass mortality event in temperate gorgonians

Global Change Biology, Journal Year: 2023, Volume and Issue: 29(22), P. 6159 - 6162

Published: Sept. 8, 2023

Gorgonian population after the 2022 mass mortality event (MME) in Calanques National Park. The year was marked by a historic gorgonian MME. This study describes consequences for red (Paramuricea clavata) and coral (Corallium rubrum) populations Park (Marseille, France).

Language: Английский

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Machine learning methods to predict sea surface temperature and marine heatwave occurrence: a case study of the Mediterranean Sea

Ocean science, Journal Year: 2024, Volume and Issue: 20(2), P. 417 - 432

Published: March 22, 2024

Abstract. Marine heatwaves (MHWs) have significant social and ecological impacts, necessitating the prediction of these extreme events to prevent mitigate their negative consequences provide valuable information decision-makers about MHW-related risks. In this study, machine learning (ML) techniques are applied predict sea surface temperature (SST) time series marine in 16 regions Mediterranean Sea. ML algorithms, including random forest (RForest), long short-term memory (LSTM), convolutional neural network (CNN), used create competitive predictive tools for SST. The models designed forecast SST MHWs up 7 d ahead. For each region, we performed 15 different experiments techniques, progressively sliding training testing period window 4 years from 1981 2017. Alongside SST, other relevant atmospheric variables utilized as potential predictors MHWs. Datasets European Space Agency Climate Change Initiative (ESA CCI SST) v2.1 Centre Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis 2021 train test techniques. area, results show that all methods with minimum root mean square errors (RMSEs) 0.1 °C at a 1 lead maximum values 0.8 time. regions, both RForest LSTM consistently outperformed CNN model across times. has highest skill 11 Importantly, similar dynamical Copernicus Forecasting System (MedFS) MHW forecasts, especially early days. forecasting, compare favorably MedFS 3 14 while shows superior 5 9 out regions. All occurrence confidence level greater than 50 % region. Additionally, study highlights importance incoming solar radiation predictor variability along itself.

Language: Английский

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Record-breaking persistence of the 2022/23 marine heatwave in the Mediterranean Sea

Environmental Research Letters, Journal Year: 2023, Volume and Issue: 18(11), P. 114041 - 114041

Published: Oct. 12, 2023

Abstract Since May 2022, the Mediterranean Sea has been experiencing an exceptionally long marine heatwave event. Warm anomalies, mainly occurring in Western basin, have persisted until boreal spring 2023, making this event longest heat wave of last four decades. In work, 2022/2023 anomaly is characterized, using in-situ and satellite measurements, together with state art reanalysis products. The role atmospheric forcing also investigated; onset growth sea surface temperature anomalies found to be related prevalence anticyclonic conditions atmosphere, which caused severe droughts region over same period. Analysis observations from Lampedusa station ocean reanalyzes reveals that wind-driven vertical mixing led penetration warm below surface, where they for several months, particularly central part basin. evolution 2022/23 compared 2003 event, put recent context climate change.

Language: Английский

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The Heatwave of Summer 2022 in the North-Western Mediterranean Sea: Some Species Were Winners

Water, Journal Year: 2024, Volume and Issue: 16(2), P. 219 - 219

Published: Jan. 8, 2024

The warming trend of the Mediterranean Sea is a long-term process. It has resulted in northwards and westwards range expansion abundance increase thermophilic species, both native non-indigenous, shrinking cold-affinity species. Marine heatwaves (MHWs) are relatively short-term extreme episodes that responsible for spectacular mortality events some species have been extensively reported literature. In contrast, benefit from MHWs (the ‘winners’) much less studied. A record-breaking MHW occurred 2022 north-western Sea. We focus on three ‘winner’ green macroalgae Penicillus capitatus Microdictyon umbilicatum endemic seagrass Posidonia oceanica. capitatus, which mainly present area as an inconspicuous turf entangled filaments (espera stage), produced erect paintbrush-like stage where sexual reproduction takes place. umbilicatum, usually uncommon, bloomed to point clogging fishing nets. Finally, mass flowering P. oceanica late August–September, followed following year (April–May 2023) by extensive production dissemination fruits seeds. Both processes, one-off heatwaves, ‘losers’ ‘winners’, shape change structure functioning ecosystems.

Language: Английский

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When resilience is not enough: 2022 extreme marine heatwave threatens climatic refugia for a habitat‐forming Mediterranean octocoral

Journal of Animal Ecology, Journal Year: 2024, Volume and Issue: unknown

Published: June 12, 2024

Abstract Climate change is impacting ecosystems worldwide, and the Mediterranean Sea no exception. Extreme climatic events, such as marine heat waves (MHWs), are increasing in frequency, extent intensity during last decades, which has been associated with an increase mass mortality events for multiple species. Coralligenous assemblages, where octocoral Paramuricea clavata lives, strongly affected by MHWs. The Medes Islands Marine Reserve (NW Mediterranean) was considered a climate refugia P. , their populations were showing some resilience to these changing conditions. In this study, we assessed impacts of MHWs that occurred between 2016 2022 seven shallow from Protected Area. years rates increased significantly ones strong MHWs, being one higher mortalities. 2022, 50 MHW days, proportion total colonies almost 70%, injured surface 40%, reaching levels never attained our study site since monitoring started. We also found spatial variability monitored populations. Whereas few them showed low mortality, others lost around 75% biomass. significant documented here raise concerns about future across Mediterranean, suggesting species may not be maintained sustain face ongoing warming trends.

Language: Английский

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Exceptional thinning through the entire altitudinal range of Mont-Blanc glaciers during the 2021/22 mass balance year

Journal of Glaciology, Journal Year: 2023, Volume and Issue: unknown, P. 1 - 6

Published: Nov. 29, 2023

Abstract Widespread glacier losses have been observed in most glaciated regions on Earth during recent decades, with a typical pattern of strong thinning their lower reaches and limited elevation changes accumulation areas. Here, we use Pléiades satellite stereo-images the Mont-Blanc massif (Alps) to reveal that took place through entire range exceptional 2021/22 mass-balance year. Above 3000 m a.s.l. Argentière Mer de Glace, rates exceeded 3.5 −1 while almost no change occurred previous 9 years. Below a.s.l., these anomalous are essentially explained by surface mass balance. At higher altitudes, other processes such as firn densification may play role. Our analysis shows high altitude glaciers, mostly stable last 100 years, now responding impact climate change.

Language: Английский

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Unraveling the Impact of Marine Heatwaves on the Eukaryome of the Emblematic Mediterranean Red Coral Corallium rubrum

ISME Communications, Journal Year: 2025, Volume and Issue: 5(1)

Published: Jan. 1, 2025

Global warming is intensifying heatwaves worldwide, leading to more frequent and severe temperature extremes. This study investigates the impact of unprecedented 2022 Mediterranean on coral eukaryome, which has received little attention despite its known importance holobiont functioning. Fifty-six colonies iconic red Corallium rubrum from Sea were collected at different sites, depths, health states. The microeukaryotic communities analyzed using an 18S rRNA gene metabarcoding approach. Primers designed reduce amplification sequences while being universal for microeukaryotes. Our results showed that eukaryome was dominated by Dino-Group I, Licnophoridae, Labyrinthulomycetes in control sites not affected heat waves. In heat-affected colonies, composition changed, with relative abundances Ephelotidae, Exobasidiomycetes, Corallicolidae, Labyrinthulomycetes, and/or epibionts Phaeophyceae increasing depending intensity stress experienced colonies. It thus possible link colony changes eukaryome. Finally, we illustrated putative interactions (competition, predator-prey relationship, parasitism) occurring within C. could explain compositional observed under stress. findings improve our understanding ecological effects marine ecosystems.

Language: Английский

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Decadal changes in phytoplankton functional composition in the Eastern English Channel: possible upcoming major effects of climate change

Ocean science, Journal Year: 2025, Volume and Issue: 21(2), P. 679 - 700

Published: March 20, 2025

Abstract. Global change is known to exert a considerable impact on marine and coastal ecosystems, affecting various parameters such as sea surface temperature (SST), runoff, circulation patterns the availability of limiting nutrients (like nitrogen, phosphorus silicon), with each influencing phytoplankton communities differently. This study based weekly fortnightly in vivo fine-spatial-resolution (∼ 1 km) observations along an nearshore–offshore gradient French waters Eastern English Channel Strait Dover. The functional composition was addressed by automated “pulse-shape recording” flow cytometry, coupled analysis environmental variables over last decade (2012–2022). method allows for characterization almost entire size range (from 0.1 800 µm width) determination abundance groups optical single-cell signals (fluorescence scatter). We explored seasonal, spatial decadal dynamics environment strongly influenced tides currents. Over past 11 years, SST has shown increasing trend at all stations, nearshore warming faster than offshore (+1.05 °C vs. +0.93 °C). Changes nutrient concentrations have led imbalances ratios (N:P:Si) relative reference ratios. However, return balanced been observed since 2019. total also increased aforementioned decade, higher contribution small-sized cells (picoeukaryotes picocyanobacteria) decrease microphytoplankton, particularly near coast. Based abundance, winters 2013–2014 2019–2020 were identified shifting periods this time series. These changes community, favoring smallest groups, could lead reduction productivity which could, turn, affect trophic levels food web.

Language: Английский

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Collective Mapping of Urban Heat: A Participatory Citizen Science Methodology for Urban Green Strategic Planning for Climate Change Adaptation

Published: Jan. 1, 2025

Language: Английский

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