Increasing heatwave frequency in streams and rivers of the United States

Limnology and Oceanography Letters, Journal Year: 2022, Volume and Issue: 8(2), P. 295 - 304

Published: Oct. 3, 2022

Abstract Heatwaves are increasing in frequency, duration, and intensity ocean, coastal, lake ecosystems. While positive water temperature trends have been documented many rivers, heatwaves not analyzed. This study examined rivers throughout the United States between 1996 2021. Riverine increased frequency over period, with most robust increases occurring summer fall, mid‐ to high‐order streams, at free‐flowing sites above a reservoir. The increase heatwave was accompanied by an moderate strength as well doubling of annual mean total number days site. were often associated normal or below‐normal discharge conditions ≤ 250 m 3 s −1 . These results provide first assessment for large geographic area States.

Language: Английский

---

Marine heatwaves and decreased light availability interact to erode the ecophysiological performance of habitat‐forming kelp species

Journal of Phycology, Journal Year: 2023, Volume and Issue: 59(3), P. 481 - 495

Published: March 25, 2023

Coastal marine ecosystems are threatened by a range of anthropogenic stressors, operating at global, local, and temporal scales. We investigated the impact heatwaves (MHWs) combined with decreased light availability over two seasons on ecophysiological responses three kelp species (Laminaria digitata, L. hyperborea, ochroleuca). These function as important habitat-forming foundation organisms in northeast Atlantic have distinct but overlapping latitudinal distributions thermal niches. Under low-light conditions, summertime MHWs induced significant declines biomass, blade surface area, Fv/Fm values (a measure photosynthetic efficiency) cool-water kelps digitata albeit to varying degrees. high-light all were largely resistant simulated MHW activity. In springtime, had minimal impacts some cases promoted performance, while reduced resulted lower growth rates. While negatively affected summer under conditions (particularly digitata), they generally resilient conditions. As such, maintaining good environmental quality water clarity may increase resilience populations MHWs. Our study informs predictions how will be interacting, concurrent typical compound events that intensifying climate change.

Language: Английский

---

Impacts of droughts and heatwaves on river water quality worldwide

Journal of Hydrology, Journal Year: 2023, Volume and Issue: 629, P. 130590 - 130590

Published: Dec. 6, 2023

Droughts and heatwaves have a major impact on river water quality worldwide. However, previous studies of under these climate extremes are limited to small number basins regions, mainly located in North America, Europe or Australia. In this study, we estimate the large-scale effects droughts, compound drought-heatwave events for total 314,046 monitoring stations worldwide over period 1980-2021. We focus 16 constituents grouped into physical (e.g., temperature, salinity), chemical pharmaceuticals, pesticides) biological biochemical oxygen demand, faecal coliform). Further, analyse response each constituent droughts relation type, land use level wastewater treatment. find general deterioration globally most rivers considered. For example, there is average 27% increase 17% decrease dissolved 24% salinity heatwaves. addition, that treatment significant effect magnitude during extreme events. The median temperature drought-heatwaves strongly driven by zone with higher warming rates at polar (+4.5°C) compared tropical (+2.1°C). Increases two times larger irrigated regions non-irrigated regions. concentrations nutrients (P N) can either depending nutrient form (dissolved vs. particulate) (urban rural). Higher levels contributed greater pathogenic (as indicated Pharmaceuticals show mixed responses persistence surface waters, instance declines diclofenac due increased decay temperatures. results study provide broader understanding how affect local regional-scale analyses. could basis modelling

Language: Английский

---

Impacts of Marine Heatwaves on Subsurface Temperatures and Dissolved Oxygen in the Chesapeake Bay

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(3)

Published: Feb. 26, 2024

Abstract Subsurface impacts associated with Marine Heatwaves (MHWs) in estuaries are not well understood, largely due to data scarcity. Using over three decades (1986–2021) of observations from several monitoring programs, this study investigates subsurface temperature and dissolved oxygen (DO) anomalies surface MHWs the Chesapeake Bay (CB). Seasonal variability followed a simple 1‐D response heating downward heat transport diffusion controlled by seasonally variable stratification mixing. Two distinct regimes were found: thermally stratified spring‐summer regime, when positive confined mixed layer (SML); homogeneous fall‐winter regime. Additionally, (subsurface) temperatures elevated for months (days weeks) before after MHWs, indicating individual events shorter than timescales temperatures. A SML budget identified air‐estuary flux changes as leading driver MHW onsets declines, latent being dominant term. DO anomaly patterns more complex, considerable along‐channel gradients. Notable decreases (1–4 mg L −1 ) primarily occurred winter/spring below SML, hypoxic zone expanded spring through fall. Only small fraction these could be attributed temperature‐induced solubility changes, demonstrating that other physical and/or biogeochemical processes dominate during events. In CB, concurrent low persistent high compound on valuable ecosystem, event likely exacerbated climate change.

Language: Английский

---

Marine heatwaves in shallow coastal ecosystems are coupled with the atmosphere: Insights from half a century of daily in situ temperature records

Frontiers in Climate, Journal Year: 2022, Volume and Issue: 4

Published: Nov. 3, 2022

Marine heatwaves (MHWs) are extreme ocean temperature events that can have wide-ranging and pervasive effects on marine species ecosystems. However, studies of MHW characteristics drivers primarily focus open-ocean environments, rather than the nearshore coastal (<10 km from coast, <50 m depth). This is despite waters sustaining significant commercial, recreational, customary fisheries aquaculture activities highly susceptible to impacts MHWs. The two longest (>50 year) daily in situ records Southern Hemisphere used investigate variability, drivers, trends MHWs shallow water ecosystems (SWMEs). Located at northern southern limits New Zealand, both locations experience an average three annually, with exposed coastline site generally being longer duration but less intense those observed within semi-enclosed harbor site. Observed timescales similar synoptic weather systems (9–13 days) most during Austral summer little seasonality frequency or duration. An investigation co-occurring offshore suggests (e.g., harbors, estuaries) more closely coupled local atmospheric conditions likely a occurring coastlines. Composite analysis using reanalysis product elucidates specific pressure systems, wind speed latent heat fluxes important contributing factors generation decline SWMEs. Investigation long-term properties revealed increase annual days decrease maximum intensity consistent broad-scale warming previously documented these stations, differences related changes large-scale circulation patterns around Zealand. Our results highlight importance data for ocean, role forcing modulating occurrence SWMEs, which cause decoupling dynamics surrounding shelf sea.

Language: Английский

---

Warming and hypoxia threaten a valuable scallop fishery: A warning for commercial bivalve ventures in climate change hotspots

Global Change Biology, Journal Year: 2023, Volume and Issue: 29(8), P. 2043 - 2045

Published: Jan. 19, 2023

Marine molluscs constitute the second largest marine fishery and are often caught in coastal estuarine habitats. Temperature is increasing these habitats at a rate greater than predicted, especially warming "hotspots". This accompanied by hypoxia duo of stressors that threatens mollusc fisheries aquaculture. Collapses northern bay scallop (Argopecten irradians irradians) on Atlantic coast USA likely to be driven rapid rates may provide an ominous glimpse into prospects other climate hotspots.

Language: Английский

---

Compound marine cold spells and hypoxic events in a nearshore upwelling system

Estuarine Coastal and Shelf Science, Journal Year: 2024, Volume and Issue: 300, P. 108706 - 108706

Published: March 12, 2024

Prolonged periods of extreme warm and cold seawater temperature anomalies, known as marine heatwaves (MHWs) spells (MCSs), respectively, can have significant impacts on coastal ecosystems. Prior research has examined the co-occurrence multiple extremes [low dissolved oxygen (DO) and/or low pH] during MHWs, with impact these compound events potentially exceeding that a single stressor due to synergistic effects. However, we are not aware any studies MCSs, despite ecosystem implications. Along Eastern Boundary Current Upwelling Systems (EBUS), strong-wind driven upwelling led reduced warming trends persistence well an increased seasonal risk for hypoxia via cross-shelf advection cold, DO subthermocline waters. In this short communication, investigated first time MCS-hypoxic at nearshore site in central California using several decades water data, short-term data from Cooperative Oceanic Fisheries Investigations program. From 1988 2020, identified 55 MCS events, 50 (∼90.9%) initiated anomalously strong upwelling. Using long-term temperature-DO relationships, 20 (∼34.6%) potential average duration 11.7 days. These occurred almost exclusively major season (March June) when there is high propensity waters adjacent shelf into nearshore. This work provides investigation hypoxic system baseline assessing future changes changing climate, important implications health EBUS globally.

Language: Английский

---

Increasing duration of heatwaves poses a threat to oyster sustainability in the Gulf of Mexico

Ecological Indicators, Journal Year: 2024, Volume and Issue: 162, P. 112015 - 112015

Published: April 11, 2024

The future of the wild oyster fishery in northern Gulf Mexico is largely uncertain due to changing environmental conditions and declining abundance harvestable oysters. Specifically, rising temperatures can directly impact physiological thresholds eastern (Crassostrea virginica) at all life history stages alter narrow ecological niche this occupies. likely most pronounced during atmospheric heatwaves, defined as three or more days above 90th percentile daily maximum air temperatures, which have been shown be increasing frequency. Increasing exposure high temperature extremes may contribute exacerbate an already fishery. Critical health recruitment i.e., addition new biomass, a dynamic process strongly driven by temperature. Here, we examine relationship between heatwave characteristics prediction poor recruitment, measured post-larval oysters (e.g. spat) below site-specific median density observed historically productive fisheries over 46-years (1976 – 2020) Mobile Bay, Alabama 21-years (1993 2014) Apalachicola Florida. We acquired measurements 50 years (1970 weather monitoring stations adjacent bays identify site specific annual events (maximum yearly temperature, consecutive days, number heatwaves). Then, with extreme heatwaves that exceeded 75th for 50-year were compared non-extreme events. Years total correlated low density. Across both bay systems, if 11 then occurred 83 % time. Extreme duration indicator has potential powerful tool managers forecast inform sustainable harvest based on year-to-year variability long-term warming trends. Our findings illustrate how multiple stressors resulting loss keystone species healthy resilient coastal ecosystems.

Language: Английский

---

Effects of basin-scale climate modes and upwelling on nearshore marine heatwaves and cold spells in the California Current

Scientific Reports, Journal Year: 2023, Volume and Issue: 13(1)

Published: July 31, 2023

Marine heatwaves and cold spells (MHWs/MCSs) have been observed to be increasing globally in frequency intensity based on satellite remote sensing continue pose a major threat marine ecosystems worldwide. Despite this, there are limited in-situ observational studies the very shallow nearshore region, particularly Eastern Boundary Current Upwelling Systems (EBUS). We analyzed unique dataset collected waters along central California spanning more than four decades (1978-2020) assessed links with basin-scale climate modes [Pacific Decadal Oscillation (PDO) El Niño (MEI)] regional-scale wind-driven upwelling. found no significant increase/decrease MHW/MCS frequency, duration, or over last decades, but did observe considerable interannual variability linked modes. Additionally, was decrease both occurrence during upwelling season, initiation of individual MHWs/MCSs coincided anomalous Most notably, co-occurrence warm (cold) phases PDO MEI negative (positive) anomalies strongly enhanced relative positive (negative) temperature MHW (MCS) days. Collectively, forcing play key role predicting extreme events shaping resilience EBUS.

Language: Английский

---

Physical and Biogeochemical Conditions and Trends in Texas Estuaries

Estuaries of the world, Journal Year: 2025, Volume and Issue: unknown, P. 205 - 220

Published: Jan. 1, 2025

Language: Английский

---