792 research outputs found
Marine Heat Waves
Marine heatwave data sets are calculated by NOAA’s National Centers for Environmental Information using Optimum Interpolation Sea Surface Temperature (OISST) data. The NOAA 1/4° OISST is a long-term Climate Data Record that incorporates observations from different platforms (satellites, ships, buoys and Argo floats) into a regular global grid. The in situ component of this input is critical
Emerging risks from marine heat waves
Recent marine heat waves have caused devastating impacts on marine ecosystems. Substantial progress in understanding past and future changes in marine heat waves and their risks for marine ecosystems is needed to predict how marine systems, and the goods and services they provide, will evolve in the future
Marine Heat Waves Hazard 3D Maps and the Risk for Low Motility Organisms in a Warming Mediterranean Sea
Frequency and severity of heat waves is expected to increase as a consequence of climate change with important impacts on human and ecosystems health. However, while many studies explored the projected occurrence of hot extremes on terrestrial systems, few studies dealt with marine systems, so that both the expected change in marine heat waves occurrence and the effects on marine organisms and ecosystems remain less understood and surprisingly poorly quantified. Here we: (i) assess how much more frequent, severe, and depth-penetrating marine heat waves will be in the Mediterranean area in the next decades by post-processing the output of an ocean general circulation model; and (ii) show that heat waves increase will impact on many species that live in shallow waters and have reduced motility, and related economic activities. This information is made available also as a dataset of temperature threshold exceedance indexes that can be used in combination with biological information to produce risk assessment maps for target species or biomes across the whole Mediterranean Sea. As case studies we compared projected heat waves occurrence with thermotolerance thresholds of low motility organisms. Results suggest a deepening of the survival horizon for red coral (Corallium rubrum, a commercially exploited benthic species already subjected to heat-related mass mortality events) and coralligenous reefs as well as a reduction of suitable farming sites for the mussel Mythilus galloprovincialis. In recent years Mediterranean circalittoral ecosystems (coralligenous) have been severely and repeatedly impacted by marine heat waves. Our results support that equally deleterious events are expected in the near future also for other ecologically important habitats (e.g., seagrass meadows) and aquaculture activities (bivalvae), and point at the need for mitigation strategies
Assessing marine heat waves in the Mediterranean Sea: a comparison of fixed and moving baseline methods
The study of marine heat waves as extreme temperature events has a wide range of applications, from a gauge for ecological and socioeconomic impact to a climate change indicator. Various definitions of marine heat waves as extreme sea temperature events exist to account for its broad applicability, with statistical definitions based on percentile based thresholds being widespread in its use. Using satellite and model data of the Mediterranean Sea, we analyze the statistical implications of choosing baseline climatological periods for threshold delineation, which are either fixed in the past or shifted in time. We show that in the context of a warming Mediterranean Sea, using a fixed baseline leads to a saturation of marine heat wave days that compromises the significance of this marine indicator, with 90% of climate models analyzed predicting an average above 189 marine heat wave days per year by 2050 even for the lowest emission scenario. We argue that only with a moving baseline, can we reach a definition for marine heat waves which yield consistently rare extreme events
Simulated Marine Heat Wave Alters Abundance and Structure of Vibrio Populations Associated with the Pacific Oyster Resulting in a Mass Mortality Event
© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Marine heat waves are predicted to become more frequent and intense due to anthropogenically induced climate change, which will impact global production of seafood. Links between rising seawater temperature and disease have been documented for many aquaculture species, including the Pacific oyster Crassostrea gigas. The oyster harbours a diverse microbial community that may act as a source of opportunistic pathogens during temperature stress. We rapidly raised the seawater temperature from 20 °C to 25 °C resulting in an oyster mortality rate of 77.4%. Under the same temperature conditions and with the addition of antibiotics, the mortality rate was only 4.3%, strongly indicating a role for bacteria in temperature-induced mortality. 16S rRNA amplicon sequencing revealed a change in the oyster microbiome when the temperature was increased to 25 °C, with a notable increase in the proportion of Vibrio sequences. This pattern was confirmed by qPCR, which revealed heat stress increased the abundance of Vibrio harveyi and Vibrio fortis by 324-fold and 10-fold, respectively. Our findings indicate that heat stress-induced mortality of C. gigas coincides with an increase in the abundance of putative bacterial pathogens in the oyster microbiome and highlights the negative consequences of marine heat waves on food production from aquaculture
Climate-driven regime shift of a temperate marine ecosystem.
Ecosystem reconfigurations arising from climate-driven changes in species distributions are expected to have profound ecological, social, and economic implications. Here we reveal a rapid climate-driven regime shift of Australian temperate reef communities, which lost their defining kelp forests and became dominated by persistent seaweed turfs. After decades of ocean warming, extreme marine heat waves forced a 100-kilometer range contraction of extensive kelp forests and saw temperate species replaced by seaweeds, invertebrates, corals, and fishes characteristic of subtropical and tropical waters. This community-wide tropicalization fundamentally altered key ecological processes, suppressing the recovery of kelp forests
Gymnodinium catenatum paralytic Shellfish toxin production and photobiological responses under marine heat waves
Marine heatwaves (MHWs) have doubled in frequency since the 1980s and are projected
to be exacerbated during this century. MHWs have been shown to trigger harmful algal blooms
(HABs), with severe consequences to marine life and human populations. Within this context, this
study aims to understand, for the first time, how MHWs impact key biological and toxicological
parameters of the paralytic shellfish toxin (PST) producer Gymnodinium catenatum, a dinoflagellate
inhabiting temperate and tropical coastal waters. Two MHW were simulated—category I (i.e., peak:
19.9 ◦C) and category IV (i.e., peak: 24.1 ◦C)—relative to the estimated baseline in the western
coast of Portugal (18.5 â—¦C). No significant changes in abundance, size, and photosynthetic efficiency
were observed among treatments. On the other hand, chain-formation was significantly reduced
under category IV MHW, as was PSP toxicity and production of some PST compounds. Overall, this
suggests that G. catenatum may have a high tolerance to MHWs. Nevertheless, some sublethal effects
may have occurred since chain-formation was affected, suggesting that these growth conditions may
be sub-optimal for this population. Our study suggests that the increase in frequency, intensity, and
duration of MHWs may lead to reduced severity of G. catenatum blooms.info:eu-repo/semantics/publishedVersio
Effects of Current and Future Summer Marine Heat Waves on Posidonia oceanica: Plant Origin Matters?
Marine heat waves (MHWs), prolonged discrete anomalously warm water events, have been increasing significantly in duration, intensity and frequency all over the world, and have been associated with a variety of impacts including alteration of ecosystem structure and function. This study assessed the effects of current and future MHWs on the Mediterranean seagrass Posidonia oceanica performance, also testing the importance of the thermal environment where the plant lives. The effects of current MHWs were studied through a mensurative experiment in a cold and in a warm site (West and North-West Sardinia, Italy, respectively). Future MHWs effects were tested through a manipulative experiment using P. oceanica shoots collected from the cold and warm sites and transplanted in a common garden in front of a power plant (North-West Sardinia): here plants were exposed to heat longer in duration and stronger in intensity than the natural MHWs of the last 20 years, resembling the future scenario. Morphological (total # of leaves, maximum leaf length, and percentage of total necrotic leaf length per shoot) and biochemical variables (leaf proteins, carbohydrates, and lipids) were considered. Plants had similar sublethal responses in both the experiments for most of the variables, revealing that current and future MHWs had similar effect types, but different in magnitude depending on the intensity of the waves: in general, the number of leaves, the maximum leaf length and lipid content decreased, while the leaf necrosis and carbohydrates increased. However, also the origin of the plants affected the results, corroborating the hypothesis that the thermal context the plants live affects their tolerance to the heat. Overall, this study provided evidence about the importance of biochemical variations, such as carbohydrate and lipid levels, as potentially good indicators of seagrass heat stress.En prens
Effects of Current and Future Summer Marine Heat Waves on Posidonia oceanica: Plant Origin Matters?
Marine heat waves (MHWs), prolonged discrete anomalously warm water events, have
been increasing significantly in duration, intensity and frequency all over the world,
and have been associated with a variety of impacts including alteration of ecosystem
structure and function. This study assessed the effects of current and futureMHWs on the
Mediterranean seagrass Posidonia oceanica performance, also testing the importance
of the thermal environment where the plant lives. The effects of current MHWs were
studied through a mensurative experiment in a cold and in a warm site (West and
North-West Sardinia, Italy, respectively). Future MHWs effects were tested through a
manipulative experiment using P. oceanica shoots collected fromthe cold and warmsites
and transplanted in a common garden in front of a power plant (North-West Sardinia):
here plants were exposed to heat longer in duration and stronger in intensity than
the natural MHWs of the last 20 years, resembling the future scenario. Morphological
(total # of leaves, maximum leaf length, and percentage of total necrotic leaf length
per shoot) and biochemical variables (leaf proteins, carbohydrates, and lipids) were
considered. Plants had similar sublethal responses in both the experiments for most
of the variables, revealing that current and future MHWs had similar effect types, but
different in magnitude depending on the intensity of the waves: in general, the number
of leaves, the maximum leaf length and lipid content decreased, while the leaf necrosis
and carbohydrates increased. However, also the origin of the plants affected the results,
corroborating the hypothesis that the thermal context the plants live affects their tolerance
to the heat. Overall, this study provided evidence about the importance of biochemical
variations, such as carbohydrate and lipid levels, as potentially good indicators of
seagrass heat stress
Marine heat waves detection in climate warming seas: their evolution in the NW Mediterranean sea
Ponencia presentada en: XII Congreso de la Asociación Española de ClimatologÃa celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]El aumento extremo y prolongado de la temperatura del mar, una ola de calor marina
(MHW), se detecta por comparación con los valores históricos en cada localización y
época del año. AsÃ, el correcto establecimiento de los valores de referencia es una
tarea clave en la detección de MHW. Al comparar diferentes épocas es necesario
considerar dos contribuciones a la evolución de los episodios extremos: la tendencia
subyacente de la temperatura y los cambios súbitos de la misma. Siguiendo la
definición de Hobday (2016), comparamos las MHW detectadas en caso de corregir
o no la tendencia climatológica en la definición de los valores de referencia. Para ello
empleamos 38 años de temperatura superficial del mar Mediterráneo proporcionados
por el servicio Copernicus. El trabajo se centra alrededor de la reserva marina de las
islas Columbretes, donde existe una estación costera de medición de la temperatura
del mar integrada en la red T-MedNet. Esto permite vislumbrar el efecto a diferentes
profundidades aunque con series temporales más cortas. El resultado es que no
corregir la tendencia al definir la referencia subestima el número de eventos
detectados en los primeros años de la serie y los sobreestima en los últimos,
independientemente de la longitud de la serie. La influencia del cambio climático en
la alteración de los ecosistemas marinos debido a las MHW no parece deberse al
incremento en la frecuencia de las mismas, sino a que éstas tienen lugar en un mar
cada vez más caliente, actuando sobre sistema biológicos con mayor estrés térmico.[EN]Extreme and prolonged increases in the sea temperature, a marine heatwave (MHW),
are detected by comparison with historical values at each location and time of year.
Thus, the correct estimation of reference values is key in detecting marine heatwaves.
In temporally separated epochs comparison, it is necessary to consider two
contributions to the evolution of extreme events: the underlying trend in temperature and its sudden changes. Following the definition of Hobday (2016), we compare the
detected MHW in case of correcting or not the climatological trend in the definition
of the reference values. We use 38 years of the surface temperature of the
Mediterranean Sea provided by the Copernicus service. This work is centered around
the Columbretes Islands marine reserve, where there is a coastal sea temperature
measurement station integrated into the T-MedNet network. This allows us to have a
glimpse of the effect at different depths but with shorter time series. The results show
that if the long-term trend is not removed from the reference, then the number of
events is underestimated in the first years of the series and overestimated in the last
ones regardless of the length of the series. The influence of climate change on the
alteration of marine ecosystems caused by the MHWs does not seem to be caused by
the increased frequency of MHWs, but rather by the fact that the MHWs take place in
an increasingly hot sea, acting on biological systems having greater thermal stress.This is a contribution made with the support
of the MPA-Engage project (Grant:5216 | 5MED18_3.2_M23_007) and MINKE
project (Grant: 101008724). The authors would like to thank the institutional support
of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)
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