Explore the vast range of titles available.

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

We document changes in the number of sightings and timing of humpback ( Megaptera novaeangliae ), blue ( Balaenoptera musculus ), and gray ( Eschrichtius robustus ) whale migratory phases in the vicinity of the Farallon Islands, California. We hypothesized that changes in the timing of migration off central California were driven by local oceanography, regional upwelling, and basin-scale climate conditions. Using 24 years of daily whale counts collected from Southeast Farallon Island, we developed negative binomial regression models to evaluate trends in local whale sightings over time. We then used linear models to assess trends in the timing of migration, and to identify potential environmental drivers. These drivers included local, regional and basin-scale patterns; the latter included the El Niño Southern Oscillation, the Pacific Decadal Oscillation, and the North Pacific Gyre Oscillation, which influence, wind-driven upwelling, and overall productivity in the California Current System. We then created a forecast model to predict the timing of migration. Humpback whale sightings significantly increased over the study period, but blue and gray whale counts did not, though there was variability across the time series. Date of breeding migration (departure) for all species showed little to no change, whereas date of migration towards feeding areas (arrival) occurred earlier for humpback and blue whales. Timing was significantly influenced by a mix of local oceanography, regional, and basin-scale climate variables. Earlier arrival time without concomitant earlier departure time results in longer periods when blue and humpback whales are at risk of entanglement in the Gulf of the Farallones. We maintain that these changes have increased whale exposure to pot and trap fishery gear off the central California coast during the spring, elevating the risk of entanglements. Humpback entanglement rates were significantly associated with increased counts and early arrival in central California. Actions to decrease the temporal overlap between whales and pot/trap fishing gear, particularly when whales arrive earlier in warm water years, would likely decrease the risk of entanglements.

From 11 April to 11 June 2018 a new type of ocean observing platform, the Saildrone surface vehicle, collected data on a round-trip, 60-day cruise from San Francisco Bay, down the U.S. and Mexican coast to Guadalupe Island. The cruise track was selected to optimize the science team’s validation and science objectives. The validation objectives include establishing the accuracy of these new measurements. The scientific objectives include validation of satellite-derived fluxes, sea surface temperatures, and wind vectors and studies of upwelling dynamics, river plumes, air–sea interactions including frontal regions, and diurnal warming regions. On this deployment, the Saildrone carried 16 atmospheric and oceanographic sensors. Future planned cruises (with open data policies) are focused on improving our understanding of air–sea fluxes in the Arctic Ocean and around North Brazil Current rings.

Marine heatwaves (MHWs) are among the greatest threats to marine ecosystems, and while substantial advances have been made in oceanic MHWs, little is known about estuarine MHWs. Utilizing a temperature dataset spanning over two decades and 54 stations distributed across 20 estuaries in the United States National Estuarine Research Reserve System, we present a comprehensive analysis of estuarine MHW characteristics and trends. Long-term climate-change-driven warming is driving more frequent MHWs along the East Coast, and if trends continue, this region will be in a MHW state for ~ 1/3 of the year by the end of the century. In contrast, the vast majority of the West Coast showed no trends, highlighting the potential for future thermal refugia. The West Coast was more strongly influenced by climate variability through the enhancement/suppression of MHWs during different phases of climate modes, suggesting long-term predictability potential. These results can provide guidance for management actions and planning in these critical environments.

Marine heatwaves (MHWs) are increasing in frequency and intensity globally and are among the greatest threats to marine ecosystems. However, limited studies have characterized subsurface MHWs, particularly in shallow waters. We utilized nearly two decades of full water-column (~ 10 m) observations from a unique automated profiler in central California to characterize, for the first time, the vertical structure of MHWs in a shallow nearshore upwelling system. We found MHWs have similar average durations and intensities across all depths, but there were ~ 17% more bottom MHW days than surface MHW days. Nearly one third of bottom MHWs occurred independently of surface MHWs, indicating that satellites miss a significant fraction of events. MHWs showed distinct seasonality with more frequent and intense events during the fall/winter when weak stratification allowed for MHWs to occupy a larger portion of the water column and persist longer. During summer, strong stratification limited the vertical extent of MHWs, leading to surface- and bottom-trapped events with shorter durations and intensities. Additionally, MHW initiation and termination across depths was consistently linked to anomalously low and high coastal upwelling, respectively. This study highlights the need for expansion of subsurface monitoring of MHWs globally amid a warming planet.

Prolonged events of anomalously warm sea water temperature, or marine heatwaves (MHWs), have major detrimental effects to marine ecosystems and the world's economy. While frequency, duration and intensity of MHWs have been observed to increase in the global oceans, little is known about their potential occurrence and variability in estuarine systems due to limited data in these environments. In the present study we analyzed a novel data set with over three decades of continuous in situ temperature records to investigate MHWs in the largest and most productive estuary in the US: the Chesapeake Bay. MHWs occurred on average twice per year and lasted 11 days, resulting in 22 MHW days per year in the bay. Average intensities of MHWs were 3°C, with maximum peaks varying between 6 and 8°C, and yearly cumulative intensities of 72°C × days on average. Large co-occurrence of MHW events was observed between different regions of the bay (50–65%), and also between Chesapeake Bay and the Mid-Atlantic Bight (40–50%). These large co-occurrences, with relatively short lags (2–5 days), suggest that coherent large-scale air-sea heat flux is the dominant driver of MHWs in this region. MHWs were also linked to large-scale climate modes of variability: enhancement of MHW days in the Upper Bay were associated with the positive phase of Niño 1+2, while enhancement and suppression of MHW days in both the Mid and Lower Bay were associated with positive and negative phases of North Atlantic Oscillation, respectively. Finally, as a result of long-term warming of the Chesapeake Bay, significant trends were detected for MHW frequency, MHW days and yearly cumulative intensity. If these trends persist, by the end of the century the Chesapeake Bay will reach a semi-permanent MHW state, when extreme temperatures will be present over half of the year, and thus could have devastating impacts to the bay ecosystem, exacerbating eutrophication, increasing the severity of hypoxic events, killing benthic communities, causing shifts in species composition and decline in important commercial fishery species. Improving our basic understanding of MHWs in estuarine regions is necessary for their future predictability and to guide management decisions in these valuable environments.

During fall/winter off the Oregon coast, oceanographic surveys are relatively scarce because of rough weather conditions. This challenge has been overcome by the use of autonomous underwater gliders deployed along the Newport hydrographic line (NH-Line) nearly continuously since 2006. The discharge from the coastal rivers between northern California and the NH-Line reach several thousands of cubic meters per second, and the peaks are comparable to the discharge from the Columbia River. This freshwater input creates cross-shelf density gradients that together with the wind forcing and the large-scale Davidson Current results in strong northward velocities over the shelf. A persistent coastal current during fall/winter, which the authors call the Oregon Coastal Current (OCC), has been revealed by the glider dataset. Based on a two-layer model, the dominant forcing mechanism of the OCC is buoyancy, followed by the Davidson Current and then the wind stress, accounting for 61% (±22.6%), 26% (±18.6%), and 13% (±11.7%) of the alongshore transports, respectively. The OCC average velocities vary from 0.1 to over 0.5 m s−1, and transports are on average 0.08 (±0.07) Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1), with the maximum observed value of 0.49 Sv, comparable to the summertime upwelling jet off the Oregon coast. The OCC is a surface-trapped coastal current, and its geometry is highly affected by the wind stress, consistent with Ekman dynamics. The wind stress has an overall small direct contribution to the alongshore transport; however, it plays a primary role in modifying the OCC structure. The OCC is a persistent, key component of the fall/winter shelf dynamics and influences the ocean biogeochemistry off the Oregon coast.

We evaluated the clinical characteristics and outcome of tracheostomy in amyotrophic lateral sclerosis (ALS) using data from the Piemonte and Valle d'Aosta Register for ALS, a prospective epidemiological register collecting all ALS incident cases in two Italian regions. Among the 1260 patients incident in the period 1995–2004, 134 (10.6%) underwent tracheostomy. Young male patients were more likely to be tracheostomised. Site of onset (bulbar vs spinal) and period of diagnosis (1995–1999 vs 2000–2004) did not influence the likelihood of being tracheostomised. The mean duration of hospital stay was 52.0 days (SD 60.5). Overall, 27 patients died while still in hospital (20.1%). Sixty-five patients (48.5%) were discharged to home, whereas 42 (31.3%) were admitted to long-term care facilities. The median survival time after tracheostomy was 253 days. In the Cox multivariable model, the factors independently related to a longer survival were enteral nutrition, age, marital status and ALS centre follow-up. In conclusion, in an epidemiological setting, ALS survival after tracheostomy was <1 year. Sociocultural factors influence the probability of choice to be tracheostomised, even in a highly socialised health system as Italian one.

Background Given that the pathogenetic process of ALS begins many years prior to its clinical onset, examining patients’ residential histories may offer insights on the disease risk factors. Here, we analyzed the spatial distribution of a large ALS cohort in the 50 years preceding the disease onset. Methods Data from the PARALS register were used. A spatial cluster analysis was performed at the time of disease onset and at 1-year intervals up to 50 years prior to that. Results A total of 1124 patients were included. The analysis revealed a higher-incidence cluster in a large area (435,000 inhabitants) west of Turin. From 9 to 2 years before their onset, 105 cases were expected and 150 were observed, resulting in a relative risk of 1.49 ( P  = 0.04). We also found a surprising high number of patients pairs (51) and trios (3) who lived in the same dwelling while not being related. Noticeably, these occurrences were not observed in large dwellings as we would have expected. The probability of this occurring in smaller buildings only by chance was very low ( P  = 0.01 and P  = 0.04 for pairs and trios, respectively). Conclusions We identified a higher-incidence ALS cluster in the years preceding the disease onset. The cluster area being densely populated, many exposures could have contributed to the high incidence ALS cluster, while we could not find a shared exposure among the dwellings where multiple patients had lived. However, these findings support that exogenous factors are likely involved in the ALS pathogenesis.