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The eruption of the Tonga–Hunga underwater volcano in the Central Pacific on 15 January 2022 generated pronounced atmospheric pressure waves that circumvented the globe several times during the next five days. Propagating with a sound speed of ~10 spherical degrees/hour, the pressure waves forced substantial tsunami waves in the Atlantic Ocean that impacted the East Coast of the United States. Almost simultaneously, on 16-17 January 2022, a deep midlatitude cyclone crossed the East Coast. The cyclone, which formed over the northern part of the Gulf of Mexico, began to rapidly intensify as it moved northward. When it reached 40° N, the system produced a pressure change of 36 hPa/24 hours, classifying the cyclone as a “bomb cyclone”. Strong high-frequency (period

Two prominent near-field tsunamis impacted the nearby coasts of Mexico. The first tsunami was generated by a major (Mw 8.2) intraplate normal-fault earthquake on 8 September 2017 in the Gulf of Tehuantepec (Chiapas, Mexico). Tsunami waves from this event were measured by a large number of high-resolution coastal tide gauges located along the coasts of California, Mexico and Central America, by three open-ocean DART stations anchored offshore from the affected region and by several distant DARTs. The second tsunami was produced by a thrust fault Mw 7.6 earthquake on 19 September 2022 within the coastal zone of Michoacán, Mexico. The 2022 tsunami was recorded by six coastal tide gauges and a single offshore DART station. All seven instruments were located within 250 km of the source. No tsunami was detected at larger distances along the coasts of North and Central America, but the tsunami signal was detected at the Hawaii and Samoa islands. All available coastal and open-ocean data were used for comprehensive analyses of these two events. Maximum trough-to-crest wave heights for the 2017 tsunami were recorded at Puerto Chiapas (351 cm), Salina Cruz (209 cm), Acapulco (160 cm) and Huatulco (137 cm), while for the 2022 tsunami they were observed at Manzanillo (172 cm) and Zihuatanejo (102 cm). For both events, the “strengths” of the recorded tsunami waves were mostly determined by distance from the source rather than by the specific resonant characteristics of individual sites. Estimates of the frequency content (“colour”) of the two tsunami events revealed that the 2017 tsunami was mostly long-period (“reddish”), with 87% of the total tsunami energy at periods >35 min, while the 2022 tsunami was short-period (“bluish”) with 91% of energy at periods

The major (Mw 8.2) intraplate normal-fault earthquake of 8 September 2017 in the Gulf of Tehuantepec (Chiapas, Mexico) generated a strong tsunami that severely impacted the nearby coasts of Mexico and Central America. Tsunami waves in the near-field area were measured by seventeen high-resolution coastal tide gauges and by three open-ocean DART stations anchored offshore from the affected region. Data from these sites, together with those from four distant DARTs, were used for comprehensive analyses of the 2017 event. De-tided sea level time series were examined to determine the statistical and spectral characteristics of the 2017 tsunami waves along the Mexican and Central American coastline. The characteristics of the recorded waves from this near-field event were compared with those from two great far-field events: the 2010 Chile and the 2011 Tohoku tsunamis. Maximum trough-to-crest wave heights for the 2017 tsunami were recorded at Puerto Chiapas (351 cm), Salina Cruz (209 cm), Acapulco (160 cm), Huatulco (137 cm) and Acajutla, El Salvador (118 cm). While maximum 2010 and 2011 tsunami waves were observed at specific “hot spots” (sites with a high Q-factor and pronounced resonant properties, such as Manzanillo and Acapulco), the “strengths” of the recorded 2017 tsunami waves were mostly determined by distance from the source. Contrary to the maximum wave heights, the general spectral properties of the tsunami signals for all three events were highly similar at a given coastal site and mainly resemble the spectral structure of background oscillations at the same site. This similarity indicates that the frequency properties of the tsunami waveforms for a steady-state tsunami signal are mainly determined by local topographic features rather than by the source parameters. Estimates of the “colour” of an event (i.e., the open-ocean tsunami frequency content) show that the 2017 Chiapas tsunami was mostly “reddish” (long-period), with 68% (DART 43413) to 87% (DART 43412) of the total tsunami energy related to waves with periods > 35 min. In contrast, the 2010 and 2011 tsunamis were “reddish-blue”, with 48–57% associated with long-period waves (> 35 min) and 52–43% with short-period waves (2–35 min). The dominant periods of the tsunami waves were mostly linked to the shape, length, and width of the source region: the larger the source and the shallower its depth, the longer the periods of the generated tsunami waves. The complicated structure of the source explains the saturated and wide frequency-band character of the tsunami spectra. Our analysis also reveals an anisotropic nature to the 2017 tsunami waves; waves that propagated northeastward along the mainland coast of North America and southeastward along the Central American coast were significantly different from those that propagated southwestward, normal to the source orientation. This aspect of the wave field appears to be related to two distinct types of waves; “trapped (edge) waves” retained on the shelf (which plays the role of a “wave guide”), and “leaky waves” that radiate into the open ocean.

Six-year records of ocean bottom water temperatures at two locations in an isolated, sedimented deep-water (∼4500 m) basin on the western flank of the mid-Atlantic Ridge reveal long periods (months to >1 year) of slow temperature rises punctuated by more rapid (∼1 month) cooling events. The temperature rises are consistent with a combination of gradual heating by the geothermal flux through the basin and by diapycnal mixing, while the sharper cooling events indicate displacement of heated bottom waters by incursions of cold, dense bottom water over the deepest part of the sill bounding the basin. Profiles of bottom water temperature, salinity, and oxygen content collected just before and after a cooling event show a distinct change in the water mass suggestive of an incursion of diluted Antarctic Bottom Water from the west. Our results reveal details of a mechanism for the transfer of geothermal heat and bottom water renewal that may be common on mid-ocean ridge flanks. Bottom water renewal on the western flank of the mid-Atlantic Ridge is driven by rapid intrusion of cold, dense water enabled by gradual warming due to geothermal heat flux and diapycnal mixing, as revealed by six-year observational records.

We use bottom pressure records from 59 sites of the global tsunami warning system to examine the nonisostatic response of the World Ocean to surface air pressure forcing within the 4–6-day band. It is within this narrow “5-day” band that sea level fluctuations strongly depart from the isostatic inverted barometer response. Numerical simulations of the observed bottom pressures were conducted using a two-dimensional Princeton Ocean Model forced at the upper boundary by two versions of the air pressure loading: (i) an analytical version having the form of the westward propagating, 5-day Rossby–Haurwitz air pressure mode; and (ii) an observational version based on a 16-yr record of global-scale atmospheric reanalysis data with a spatial resolution of 2.5°. Simulations from the two models—consisting of barotropic standing waves of millibar amplitudes and near uniform phases in the Pacific, Atlantic, and Indian Oceans—are in close agreement and closely reproduce the observed bottom pressures. The marked similarity of the outputs from the two models and the ability of both models to accurately reproduce the seafloor pressure records indicate a pronounced dynamic response of the World Ocean to nonstationary air pressure fields resembling the theoretical Rossby–Haurwitz air pressure mode.

The major (Mw 7.9) earthquake that struck the Gulf of Alaska near Kodiak Island on 23 January 2018 was a rare, mid-plate strike-slip event that triggered a minor trans-Pacific tsunami. An analysis of the simultaneous measurements of tsunami waveforms at 21 open-ocean sites (including three independent arrays of stations) and 27 coastal tide gauges in the Gulf of Alaska and along the coast of North America has enabled us to examine properties of the 2018 tsunami, its transformation over the continental slope and shelf, and its amplification as the waves approached the coast. Results show that the tsunami wave variance decreased monotonically along the west coast from northern British Columbia to southern Oregon. Based on the variance structure, the mean amplification factor for Tofino on the west coast of Vancouver Island (a “beacon” site with a long time series), was $$A_{RMS}^{Tof}$$ = 5.3, in good agreement with corresponding estimates for four major past events; 4.5 (2009 Samoa), 4.3 (2010 Chile), 6.3 (2011 Tohoku) and 5.2 (2012 Haida Gwaii). This variance-derived amplification for Tofino was greater than the amplification factor based on the amplitude ratio ($$A_{{}}^{Tof}$$ = 3.2). Spectral analysis of the records showed that the tsunami had a relatively large high-frequency content (i.e., was “blueish”), with nearly 90% of the total energy in the open ocean at frequencies > 1.7 cph (periods

The Mw 7.6 earthquake of 19 September 2022 within the coastal zone of Michoacán, Mexico, generated a major tsunami that was recorded by six coastal tide gauges and a single offshore DART station. All seven instruments were located within 250 km of the source. No tsunami was detected at larger distances. Maximum wave heights were observed at Manzanillo (172 cm) and Zihuatanejo (102 cm). Numerical modelling of the event closely reproduced the coastal and offshore tsunami records and shows that the tsunami energy radiated seaward from the source as a narrow “searchlight” beam directed normal to the source and mainland coast. Estimates of the frequency content (“colour”) of the 2022 tsunami event, and that generated in 2017 by the much stronger (Mw 8.2) Chiapas earthquake further up the coast, reveal a marked difference in the tsunamigenic response. Whereas the 2017 tsunami was mostly long-period (“reddish”), with 87% of the total tsunami energy at periods >35 min, the 2022 tsunami was short period (“bluish”) with 91% of energy at periods

An introduced population of European green crabs Carcinus maenas (Linneaus, 1758) was established in San Francisco Bay prior to 1991. Their subsequent northern range expansion is linked to larval transport in the Davidson Current to northern California (1993), southern Oregon (approximately 1996), the Oregon and Washington coastal estuaries and the west coast of Vancouver Island, British Columbia (1998). Range expansions through larval transport to the central British Columbia coast occurred before 2010, to Haida Gwaii in 2020, and into the inland Salish Sea in 2015 and 2016. Both the range expansions of C. maenas and local abundance are strongly linked to oceanic factors during their larval development. These include (1) strong northward flow of coastal waters during winter; (2) warm surface water temperatures (>10°C for larval development); and (3) coastal circulation patterns that keep larvae close to shore, where they can be carried by wind and tidal currents into estuaries and embayments to settle. The strongest year classes and largest range expansions occurred during the last two major El Nino events. The 1997 to 1998 El Nino resulted in the colonization of embayments in Oregon, coastal Washington, and on the west coast of Vancouver Island, while the El Nino of 2015 to 2016 and the Pacific Warm Blob are linked to the range expansion into the Salish Sea. More local range expansions along the west coast of Vancouver Island, to the central British Columbia Coast, to Haida Gwaii, and inside the Salish Sea occurred during non-El Nino years.

A storm surge hindcast for the west coast of Canada was generated for the period 1980–2016 using a 2D nonlinear barotropic Princeton Ocean Model forced by hourly Climate Forecast System Reanalysis wind and sea level pressure. Validation of the modeled storm surges using tide gauge records has indicated that there are extensive areas of the British Columbia coast where the model does not capture the processes that determine the sea level variability on intraseasonal and interannual time scales. Some of the discrepancies are linked to large-scale fluctuations, such as those arising from major El Niño and La Niña events. By applying an adjustment to the hindcast using an ocean reanalysis product that incorporates large-scale sea level variability and steric effects, the variance of the error of the adjusted surges is significantly reduced (by up to 50%) compared to that of surges from the barotropic model. The importance of baroclinic dynamics and steric effects to accurate storm surge forecasting in this coastal region is demonstrated, as is the need to incorporate decadal-scale, basin-specific oceanic variability into the estimation of extreme coastal sea levels. The results improve long-term extreme water level estimates and allowances for the west coast of Canada in the absence of long-term tide gauge records data.

The five great trans-Pacific tsunamis of the 20th century that occurred in 1946, 1952, 1957, 1960 and 1964 were accurately recorded by analogue tide gauges on the coast of British Columbia. All available pen-and-paper records of these events were collected, digitised, de-tided and analysed. The 1946 Aleutian Islands event was recorded at two stations, Tofino and Victoria, where maximum trough-to-crest tsunami wave heights were 55 and 27 cm, respectively. These two gauged stations, as well as Prince Rupert, Alert Bay and Kitimat, also recorded the 1952 Kamchatka tsunami, which generated a maximum wave height of 77 cm at Tofino. The 1957 Andreanof Islands tsunami was recorded at six primary stations and the 1960 Chile tsunami by 17 primary and temporary tide gauges. For both of these events, the maximum tsunami wave heights also occurred at Tofino: 48 cm (1957) and 132 cm (1960). The 1964 Alaska tsunami remains the strongest tsunami yet instrumentally recorded on the coast of British Columbia. Our examination of 16 records from this event shows that maximum wave heights at eight stations were higher than 1 m, including Port Alberni (770 cm), Ocean Falls (376 cm), Tofino (237 cm) and Alert Bay (222 cm). We also find that the maximum wave at all stations for this event was among the first three waves. Subsequent wave heights rapidly attenuated following this group of waves. Frequency-time (f–t) analyses of the tsunami waveforms reveal that, for each station, the dominant frequencies of the waves and their evolution with time were very similar for different tsunamis, but differed considerably among sites for a particular tsunami, indicating the strong influence of local/regional topography on the incoming waves. From the latter point of view, the 1964 tsunami was exceptional. The epicentre of the 1964 Alaska earthquake was located much closer to the BC coast than for the other events and, therefore, the influence of the source was much stronger. The “ringing” of this tsunami was substantially shorter (

Tsunami-like sea level oscillations recently recorded by tide gauges located along the coasts of British Columbia (Canada) and Washington State (USA) have been identified as meteorological tsunamis. Globally, such events can create hazardous conditions in coastal areas, including the possible loss of life, and need to be taken into account in any assessment of risk to nearshore infrastructure. On 1 November 2010, a significant meteotsunami occurred in the southern Strait of Georgia, British Columbia. To examine this event, we have used all available sea level and air pressure data, including 1-min records from five Canadian Hydrographic Service and five USA National Oceanic and Atmospheric Administration tide gauges, as well as high-resolution time series from two Ocean Network Canada VENUS bottom pressure recorders and from 132 air pressure sensors within the Victoria School-Based Weather Station Network of southern British Columbia. The oceanic responses to four well-defined atmospheric disturbances (labelled D1–D4) were selected for analysis. Disturbance D3, which propagated toward ~ 100° True (eastward) at a speed of ~ 20 m/s, appears to have been responsible for generating the meteotsunami observed in the southern Strait of Georgia, while disturbance D4 that moved toward ~ 55° True at a speed of 24 m/s appears to have produced the meteotsunami observed in Juan de Fuca Strait that separates Vancouver Island from Washington State. We used the physical parameters derived for the four disturbances to force numerical simulations of the events and compared the results to observations from selected tide gauge sites. The numerical experiments revealed strongly individual sea level responses at each site to changing air pressure disturbance speed, direction and intensity, such that each location has its own set of “site-specific” air pressure characteristics that produce the strongest sea level response. Differences in the local topography and coastline geometry appear to be responsible for the different responses among sites.

Meteorological tsunamis are frequently destructive tsunami-like waves generated by small-scale atmospheric disturbances. Several devastating events occurred recently in various regions of the world oceans, including the Balearic Islands, Sicily, the Adriatic and Black seas, the Great Lakes, the west coast of South Korea, the Netherlands and the Persian Gulf. Although this phenomenon has been actively studied for more than 25 years, the exact mechanism (or mechanisms) responsible for producing these extreme events remains a puzzle. One of the major problems making it difficult to determine the physical process generating meteotsunamis is the absence of a network of simultaneously working precise tide gauges and microbarographs in the affected region. A unique set of high-resolution atmospheric data from the meteorological “school network” of 132 school stations became available for 2008-2019 for the area of southern Vancouver Island and nearby Gulf Islands located in the Strait of Georgia. These data, combined with 1-min sea level data from Canadian Hydrographic Service (CHS) and USA National Oceanic and Atmospheric Administration (NOAA) tide gauges, has enabled us to examine both the spatial and temporal features of mesoscale atmospheric disturbances and coincident properties of the associated sea level oscillations. The data analyses, supported by a series of numerical experiments, has made it possible to reconstruct observed events and to determine the specific atmospheric parameters producing the strongest sea level response in the southern part of the Strait of Georgia. These experiments have helped us to recognize the most effective (and hence, most hazardous) directions and speeds of propagating atmospheric disturbances and to identify “hot spots” along the coast that are under the highest risk of large meteotsunamis.

Ocean Networks Canada (ONC; http://www.oceannetworks.ca/) operates the multidisciplinary NEPTUNE and VENUS cabled ocean observatories off the west coast of Canada and an increasing number of miniat...

Sequences of correlated seafloor temperature, current velocity, and acoustic backscatter events recorded at Ocean Drilling Program (ODP) sites at 4300 m depth in the Middle America Trench have been inferred to result from tidally induced turbidity currents generated in the vicinity of the 3300 m deep sill at the southern end of the trench. New data from the borehole observatories extend the temperature records to 11 years (November 2002 to December 2013) and confirm the highly episodic nature of the events. We present satellite altimetry data and ocean circulation model results to show that event timing is correlated with intraseasonal Kelvin wave motions in the equatorial Pacific. The observed temperature events had a mean (±1 standard deviation) occurrence interval of 61 (±24) days, which spans the periods of the first two baroclinic modes. Lag times between peak bottom water temperatures at the ODP sites and the passage of eastward-propagating Kelvin wave crests at locations in the eastern equatorial Pacific are consistent with the time for mode-1 waves to propagate to the southern end of the trench at a mean phase speed of 2.0 m s−1. Findings indicate that Kelvin wave currents augment tidal motions in the vicinity of the sill, triggering turbidity currents that travel northwestward along the trench axis at mean speeds of ∼0.1 m s−1. We conclude that mode-1 (or, possibly, mixed mode-1 and mode-2) baroclinic Kelvin waves generated by large-scale atmospheric processes in the western tropical Pacific lead to heat and mass transport deep within Middle America Trench in the eastern tropical Pacific.

The Tohoku (East Japan) earthquake of 11 March 2011 (M w 9.0) generated a great trans-oceanic tsunami that spread throughout the Pacific Ocean, where it was measured by numerous coastal tide gauges and open-ocean DART (Deep-ocean Assessment and Reporting of Tsunamis) stations. Statistical and spectral analyses of the tsunami waves recorded along the Pacific coast of Mexico have enabled us to estimate the principal parameters of the waves along the coast and to compare statistical features of the tsunami with other tsunamis recorded on this coast. We identify coastal “hot spots”—Manzanillo, Zihuatanejo, Acapulco, and Ensenada—corresponding to sites having highest tsunami hazard potential, where wave heights during the 2011 event exceeded 1.5–2 m and tsunami-induced currents were strong enough to close port operations. Based on a joint spectral analysis of the tsunamis and background noise, we reconstructed the spectra of tsunami waves in the deep ocean and found that, with the exception of the high-frequency spectral band (>5 cph), the spectra are in close agreement with the “true” tsunami spectra determined from DART bottom pressure records. The departure of the high-frequency spectra in the coastal region from the deep-sea spectra is shown to be related to background infragravity waves generated in the coastal zone. The total energy and frequency content of the Tohoku tsunami is compared with the corresponding results for the 2010 Chilean tsunami. Our findings show that the integral open-ocean tsunami energy, I 0, was ~2.30 cm2, or approximately 1.7 times larger than for the 2010 event. Comparison of this parameter with the mean coastal tsunami variance (451 cm2) indicates that tsunami waves propagating onshore from the open ocean amplified by 14 times; the same was observed for the 2010 tsunami. The “tsunami colour” (frequency content) for the 2011 Tohoku tsunami was “red”, with about 65% of the total energy associated with low-frequency waves at frequencies 35 min). The “red colour” (i.e., the prevalence of low-frequency waves) in the 2011 Tohoku, as well as in the 2010 Chile tsunamis, is explained by the large extension of the source areas. In contrast, the 2014 and 2015 Chilean earthquakes had much smaller source areas and, consequently, induced “bluish” (high-frequency) tsunamis.

Although the European green crab Carcinus maenas has persisted in Oregon and Washington coastal estuaries, and thrived in the inlets of the west coast of British Columbia since 1998, populations of this species had not established themselves in the inner Salish Sea, between southern Vancouver Island, the mainland, and Puget Sound. It has been hypothesized that the Strait of Juan de Fuca acts as a semipermeable barrier preventing C. maenas larvae from entering this inland sea. Most years, the water is too cold ( 2.5°C above average) from the fall of 2013 to 2015 would have allowed larvae to survive alongshore transport off the coasts of Oregon, Washington, and southern British Columbia. Reversals of the estuarine current in the Strait of Juan de Fuca forced by strong southerly winds associated with major storms along the outer coast in late October 2014 and 2015 could have transported the warm ocean water and larvae inward through the strait and, with the aid of local winds and tidal currents, into the inner Salish Sea. Preferential inward transport would have been with the Olympic Peninsula Countercurrent that forms along the U.S. side of the channel.

The northwest (NW) Coast of Canada (British Columbia) stretches from Alaska to Vancouver Island with the continental shelf including the islands of Haida Gwaii, Queen Charlotte Sound, and Hecate Strait. It is mostly a rugged temperate-subarctic wilderness characterized by coastal mountain ranges, glacial fjords, and island archipelagos, with a rich First Nations cultural and marine harvesting history. Intense seasonal storms are a challenge for marine activities and biota, but marine birds, fish, and mammals are abundant. Deep sponge and coral complexes and ancient reefs have been minimally explored coastally and offshore, and numerous seamounts include one accessible by SCUBA. Economics of the sparse population are dominated by logging, diverse fin- and shell-fishing and ecotourism, which are susceptible to overexploitation, habitat destruction, and climate change. Urban contamination is low except for airborne persistent compounds from elsewhere and localized influence from a few pulp and paper mills and small sewage outfalls. Interest in oil and gas exploration has been intense historically, but moratoria on tanker traffic have suppressed development. Wind and wave energy are developing industries, but limited access remains a problem. Invasive species are still a minor issue, partly due to the lack of exotic aquaculture. Toxic algal blooms can intermittently affect shellfish harvesting. On-going efforts to protect old-growth forests and marine resources is this relatively pristine coast have resulted in extensive marine protected areas and parks, which in turn enhance ecotourism.

The three great earthquakes off the coast of Chile on 27 February 2010 (Maule, Mw 8.8), 1 April 2014 (Iquique, Mw 8.2) and 16 September 2015 (Illapel, Mw 8.3) generated major transoceanic tsunamis that spread throughout the Pacific Ocean and were measured by numerous coastal tide gauges and open-ocean DART stations. Statistical and spectral analyses of the tsunami waves from the events recorded on the Pacific coast of Mexico enabled us to estimate parameters of the waves along the coast and to compare statistical features of the events. We also identified three coastal “hot spots” (sites having maximum tsunami risk): Puerto Angel, Puerto Madero and Manzanillo. Based on the joint spectral analyses of the tsunamis and background noise, we have developed a method for using coastal observations to determine the underlying spectrum of tsunami waves in the deep ocean. The “reconstructed” open-ocean tsunami spectra are in close agreement with the actual tsunami spectra evaluated from direct analysis of the DART records offshore of Mexico. We have further used the spectral estimates to parameterize the energy of the three Chilean tsunamis based on the total open-ocean tsunami energy and frequency content of the individual events.

The California Undercurrent transports warm, salty, nutrient-rich, oxygen-depleted water along the continental slope from the equatorial Pacific to the Aleutian Islands. We use multiyear acoustic Doppler current profiler records collected simultaneously at two mooring sites off Vancouver Island to detail the regional structure of the undercurrent and to show that much of its variability is attributable to the passage of remotely forced, coastal-trapped waves. We also document two subsurface currents missed by earlier current measurements. The undercurrent becomes evident in spring, intensifies through summer and fall, and merges with the wind-driven poleward surface flow in winter. During intensification at the southern mooring site (A1), the undercurrent shoals from 250 ± 50 m in early summer to 150 ± 50 m depth in late fall. At the northern site (BP2), 225 km to the northwest of A1, the current is weaker and maintains a year-round depth of 150 ± 50 m. Temporal variability in the undercurrent velocity attains highest coherence with winds along the southern Oregon-northern California coast, with peak coherence occurring for “synoptic” (10–40 day period) alongshore winds off Cape Blanco in southern Oregon. The undercurrent lag of 3 ± 2 days relative to the Cape Blanco winds at synoptic periods is consistent with low mode, poleward propagating, coastally trapped waves. For periods >40 days, the wind-current coherence remains high for winds off the Oregon-California coast but lags are often negative, indicating possible forcing by alongshore baroclinic pressure gradients. At interannual time scales, the undercurrent variations have links to climate-scale processes in the equatorial Pacific.

The purpose of this study is to show that seafloor hydrothermal venting in the open northeast Pacific Ocean has a marked impact on secondary biomass and production within the overlying water column. Specifically, we use net tows and concurrently measured acoustic backscatter data collected over six summers to examine the effects of hydrothermal venting from the Endeavour Segment of Juan de Fuca Ridge on macro-zooplankton biomass and production throughout the entire 2000 m depth range. Previous research shows that ontogenetic diapausing migrators and their predators from the upper ocean aggregate above the neutrally buoyant plumes in summer and resume feeding on plume and bottom upwelled particles, resulting in increased zooplankton reproductive output to the upper ocean. Within the limitations of our sampling methodology, net tows reveal a statistically significant exponential decline in total water-column biomass with increasing lateral distance from the vent fields. The acoustic backscatter data show a similar decline, but only below 800 m depth. Near-surface biomass was highly variable throughout the region, but values near vents consistently ranged higher than summer values found elsewhere in the offshore northeast Pacific. Water-column biomass was similar in magnitude above and below 800 m depth throughout the region. Because epiplume biomass can be advected a considerable distance from vent fields, biomass enhancement of the water column from hydrothermal venting may extend considerable distances to the west and northwest of the vent sites, in the prevailing directions of the subsurface flow. Based on the extensive acoustic Doppler current profiler (ADCP) data collected, and the strong correlation between zooplankton production derived from net sample biomass and acoustic backscatter intensity, we estimate that daily macro-zooplankton production in the upper 400 m of the water column within 10 km of the vent fields averages approximately 16% of photosynthetic primary production (the “ Z ratio”), whereas the total water-column zooplankton production averages 26% of surface primary production. Local grazing-rate estimates, metabolic constraints and other open-ocean studies suggest that the Z ratio should be no higher than 5%, which it is at off-axis background sites in the study region. This finding indicates that nutrient sources other than upper-ocean primary production fuel both upper- and deep-ocean zooplankton biomass and growth near the Endeavour Ridge hydrothermal vents.

Trends in regional mean sea levels can be substantially different from the global mean trend. Here, we first use tide-gauge data and satellite altimetry measurements to examine trends in mean relative sea level (MRSL) for the coasts of Canada over approximately the past 50–100 years. We then combine model output and satellite observations to provide sea level projections for the twenty-first century. The MRSL trend based on historical tide-gauge data shows large regional variations, from 3 mm y−1 (higher than the global mean MRSL rise rate of 1.7 mm y−1 for 1900–2009) along the southeast Atlantic coast, close to or below the global mean along the Pacific and Arctic coasts, to –9 mm y−1 in Hudson Bay, as indicated by the vertical land motion. The combination of altimeter-measured sea level change with Global Positioning System (GPS) data approximately accounts for tide-gauge measurements at most stations for the 1993–2011 period. The projected MRSL change between 1980 and 1999 and between 2090 and ...

We examine the spatial and temporal variability of satellite-sensed sea surface chlorophyll off the west coast of North America from 1997 to 2010, with focus on coastal British Columbia. The variability in surface chlorophyll is complex. Whereas the spring bloom generates the highest phytoplankton concentration for coastal Alaska, the north and east coasts of Haida Gwaii, Queen Charlotte Sound, the Strait of Georgia, and coastal Oregon and California, it is the fall bloom that normally generates the highest concentration for the west coast of Vancouver Island, Juan de Fuca Strait, and the west coast of Washington. The highest satellite-sensed chlorophyll concentrations occur in the Strait of Georgia, where mean values are at least 2 times higher than elsewhere in the northeast Pacific. Moreover, the annual average surface chlorophyll concentration increased significantly in the Strait of Georgia during this period, with highest concentration observed during the near neutral ENSO conditions of the spring of 2007. The next highest concentrations occur off southwest Vancouver Island but have no statistically significant trend. The lowest average peak chlorophyll concentration is observed off Southern California. The timing of the highest chlorophyll concentration is latest off the coast of Washington and earliest off the coast of Southern California. Small increasing concentration trends are observed off the Washington and California coasts.

The reproductive migration of anadromous salmonids through estuarine waters is one of the most challenging stages of their life cycle, yet little is known about the environmental and physiological conditions that influence migratory behaviour. We captured, sampled tissues, tagged and released 365 sockeye salmon (Oncorhynchus nerka) homing through inner coastal waters towards the Fraser River, British Columbia, Canada. Biotelemetry was used to assess the behaviour of individual sockeye salmon approaching estuarine waters and at river entry, which were related to both fish physiological condition at release and to prevailing environmental conditions. Sockeye salmon tended to stay close to the shore, migrated during the day, and movements were related to tide. Sockeye salmon migration rate was linked to wind-induced currents, salinity and an individual's physiological state, but these factors were specific to location and stock. We propose that wind-induced currents exposed sockeye salmon entering the estuary to stronger olfactory cues associated with Fraser River water, which in turn resulted in faster migration rates presumably due to either an increased ability for olfactory navigation and/or advanced reproductive schedule through a neuroendocrine response to olfactory cues. However, once the migration had progressed further into more concentrated freshwater of the river plume, sockeye salmon presumably used wind-induced currents to aid in movements towards the river, which may be associated with energy conservation. Results from this study improve our biological understanding of the movements of Fraser River sockeye salmon and are also broadly relevant to other anadromous salmonids homing in marine environments.

A major (M w 7.7) earthquake occurred on October 28, 2012 along the Queen Charlotte Fault Zone off the west coast of Haida Gwaii (formerly the Queen Charlotte Islands). The earthquake was the second strongest instrumentally recorded earthquake in Canadian history and generated the largest local tsunami ever recorded on the coast of British Columbia. A field survey on the Pacific side of Haida Gwaii revealed maximum runup heights of up to 7.6 m at sites sheltered from storm waves and 13 m in a small inlet that is less sheltered from storms (Leonard and Bednarski 2014). The tsunami was recorded by tide gauges along the coast of British Columbia, by open-ocean bottom pressure sensors of the NEPTUNE facility at Ocean Networks Canada’s cabled observatory located seaward of southwestern Vancouver Island, and by several DART stations located in the northeast Pacific. The tsunami observations, in combination with rigorous numerical modeling, enabled us to determine the physical properties of this event and to correct the location of the tsunami source with respect to the initial geophysical estimates. The initial model results were used to specify sites of particular interest for post-tsunami field surveys on the coast of Moresby Island (Haida Gwaii), while field survey observations (Leonard and Bednarski 2014) were used, in turn, to verify the numerical simulations based on the corrected source region.

The biological productivity of coastal upwelling regions undergoes marked interannual variability as marine ecosystems respond to changes in the prevailing winds. Determination of the principal metrics that define the upwelling cycle—the spring transition, when ocean conditions switch from downwelling- to upwelling-favorable, and the Fall Transition, when conditions return to downwelling-favorable—is essential for understanding changes in coastal productivity. Here we demonstrate that upwelling in the northern California Current System may be delineated by changes in microseismic activity recorded at a broadband seismological station in southwestern British Columbia. Observed high correlation between microseismic intensity and offshore bottom pressure fluctuations at ~0.2 Hz confirms a direct link to regional wind-wave generation. Comparison of transition times derived from coincident 20 year records of microseismic intensity and alongshore wind stress for the British Columbia-Oregon coast suggests that seismically derived times may be more representative of coastal upwelling than times derived using traditional methods.

Temperature is recognized as a key factor influencing physiology, behaviour and survival of anadromous salmonids, yet little is known about their thermal experience, nor factors affecting it, during marine homeward migrations. In 2006 and 2010, approximately 1000 Fraser River sockeye salmon Oncorhynchus nerka were captured and tagged in coastal marine waters, ~215 km from the river mouth, during their spawning migration. Individual salmon were blood sampled, gastrically implanted with temperature loggers fixed to radio or acoustic tags, and released. We recovered 50 loggers from freshwater locales containing 14690 hourly temperature readings. Mixed-effects models were used to characterize marine thermal experience, and examine the association of thermal experience with initial physiological status as well as oceanographic and meteorological conditions. Sockeye salmon thermal experience was highly variable (8.4°C to 20.5°C), and we detected opposite diel patterns between study years that could be associated with moon phase, behavioural thermoregulation, olfactory/celestial navigation or predator avoidance. We were unable to find any relationships between thermal experience and environmental conditions or fish physiological state. Nonetheless, we found that the greatest variability in thermal experience was attributed to within-individual variation, suggesting that environmental and physiological variables need to be examined at different temporal and spatial scales, and/or additional environmental and physiological variables need to be assessed. Overall, the factors associated with the thermal experience of homing sockeye salmon in coastal marine environments are more complex than previously thought, and multiple year studies are needed before generalizing behavioural patterns observed from single year studies.

The California Undercurrent (CUC), a poleward-flowing feature over the continental slope, is a key transport pathway along the west coast of North America and an important component of regional upwelling dynamics. This study examines the poleward undercurrent and alongshore pressure gradients in the northern California Current System (CCS), where local wind stress forcing is relatively weak. The dynamics of the undercurrent are compared in the primitive equation Navy Coastal Ocean Model and a linear coastal trapped wave model. Both models are validated using hydrographic data and current-meter observations in the core of the undercurrent in the northern CCS. In the linear model, variability in the predominantly equatorward wind stress along the U.S. West Coast produces episodic reversals to poleward flow over the northern CCS slope during summer. However, reproducing the persistence of the undercurrent during late summer requires additional incoming energy from sea level variability applied south of the region of the strongest wind forcing. The relative importance of the barotropic and baroclinic components of the modeled alongshore pressure gradient changes with latitude. In contrast to the southern and central portions of the CCS, the baroclinic component of the alongshore pressure gradient provides the primary poleward force at CUC depths over the northern CCS slope. At time scales from weeks to months, the alongshore pressure gradient force is primarily balanced by the Coriolis force associated with onshore flow.

Pacific herring (Clupea pallasii) is an ecologically- and commercially-important species in the northeast Pacific Ocean. Detailed records of herring spawn off the coast of British Columbia (BC), Canada, collected annually since 1928, indicate that spawn distribution has gone through systematic changes over time. The cessation of spawning in some areas has led to concerns that commercial herring fisheries have resulted in serial depletion of local spawning. However, previous studies suggested that changes in spawn distribution may not necessarily be fisheries induced. Hitherto, there have been no satisfactory explanations for these changes. In this study, we developed boosted regression tree (BRT) models for four major spawning regions in BC (the Prince Rupert District, Haida Gwaii, the Central Coast, and the West Coast of Vancouver Island) to explore the nonlinear relationships between herring spawn abundance and environmental variables, including two indices of Pacific Ocean basin-scale variability (the PDO: Pacific Decadal Oscillation; and the NPGO: North Pacific Gyre Oscillation) and regional scale wind-stress off the BC coast. We find a “bowl-shaped” relationship between herring spawn abundance and two environmental variables (the PDO and NPGO) across all spawning regions and a “dome-shaped” relationship between spawn abundance and upwelling-favorable wind-stress, the latter indicating that there is an optimal range of wind stress values that favor herring spawn abundance. Results also suggest that, in Haida Gwaii, herring spawn abundance has been primarily governed by the NPGO and downwelling-favorable alongshore wind-stress; in contrast, the PDO and upwelling-favorable alongshore wind-stress are top contributors to spawn fluctuations in all other regions. These results help facilitate our understanding of how changes in physical environmental conditions affect herring spawn abundance as well as subsequent population dynamics.

[1] Tsunamis triggered by powerful earthquakes cause extensive damage and loss of life within many regions of the World Ocean. Although coastal inundation from major tsunamis is becoming increasingly well understood, we know little about the broader aspects of such events on distal marine systems. Here we use time series from moored oceanic sensors to show that the Tohoku tsunami generated by the magnitude 9.0 earthquake off eastern Japan in March 2011 caused days of surge-like currents and turbulent mixing in the inner basin of an anoxic Canadian fjord located over 7000 km from the seafloor rupture zone. Mixing, combined with the inflow of more oxygen-rich water from the adjoining outer basin, led to abrupt changes in the hydrodynamics, bottom sedimentation, and zooplankton behavior in the basin. These findings help define mechanisms by which major transoceanic tsunamis can significantly alter coastal marine environments located far from the source area.

Sediment traps were deployed inside the anoxic inner basin of Effingham Inlet and at the oxygenated mouth of the inlet from May 1999 to September 2000 in a pilot study to determine the annual depositional cycle and impact of the 1999 La Nina event within a western Canadian inlet facing the open Pacific Ocean. Total mass flux, geochemical parameters (carbon, nitrogen, opal, major and minor element contents, and stable isotope ratios) and diatom assemblages were determined and compared with meteorological and oceanographic data. Deposition was seasonal, with coarser grained terrestrial components and benthic diatoms settling in the autumn and winter, coincident with the rainy season. Marine sedimentary components and abundant pelagic diatoms were coincident with coastal upwelling in the spring and summer. Despite the seasonal differences in deposition, the typical temperate-zone Thalassiosira – Skeletonema – Chaetoceros bloom succession was muted. A July 1999 total mass flux peak and an increase in biogenous components coincided with a rare bottom-water oxygen renewal event in the inlet. Likewise, there were cooler-than-average sea surface temperatures (SSTs) just outside the inlet, and unusually high abundances of a previously undescribed cool-water marine diatom ( Fragilariopsis pacifica sp. nov.) within the inlet. Each of these occurrences likely reflects a response to the strong La Nina that followed the year after the strongest-ever recorded El Nino event of 1997–1998. By the autumn of 1999, SSTs had returned to average, and F. pacifica had all but disappeared from the remaining trap record, indicating that oceanographic conditions had returned to normal. Oxygenation events were not witnessed in the inlet in the years before or after 1999, suggesting that a rare oceanographic and climatic event was captured by this sediment trap time series. The data from this record can therefore be used as a benchmark for identifying anomalous environmental conditions on this coast.

We collated 25–30 observations of family groups of Ancient Murrelets (Synthliboramphus antiquus) between 23 May and 25 July 1988–2011 from southwest Vancouver Island, British Columbia, to central Oregon, 450–970 km south of the nearest breeding colony on Haida Gwaii, British Columbia. We proposed 2 hypotheses in explanation of the presence of these groups this far south: (1) rapid long-distance movements by swimming, assisted by strong currents, from colonies on Haida Gwaii (“rapid transport” hypothesis); or (2) undetected local breeding by small numbers of pairs at nearby southern locations (“southern nesting” hypothesis). Far-south groups were generally consistent with relatively long, southern, offshore movements from rearing areas in northern Queen Charlotte Sound, initially with more rapid southward transport by relatively strong (approximately 0.25 m/s) shelf-break currents and strong westerly winds off Vancouver Island in early summer, followed by movement inshore, supporting the rapid transport hypothesis. Nesting was reported at Carroll Island, Washington, in 1924, but apparently by an isolated pair. No evidence of breeding was recorded during seabird colony surveys on the southwest coast of Vancouver Island in 1967–1998 or on the northwest coast of Washington in 1959–1986, although most surveys were conducted June-July, too late for optimal detection of Ancient Murrelets, and some islands on the Washington coast were incompletely examined. Support for the southern nesting hypothesis is lacking but appropriately timed surveys of islands off the northwest Olympic Peninsula are needed to document any limited nesting in this area.

We collated between 22 and 26 observations of family groups of Ancient Murrelets (Synthliboramphus antiquus) between 11 June and 31 July 1949–2009, off northern Vancouver Island, British Columbia, 110–350 km south of the nearest colony and up to 115 km offshore. These occurrences are consistent with a relatively short, southern, nearshore extension of normal clockwise movements of groups in regular at-sea rearing areas in southern Hecate Strait and northern Queen Charlotte Sound. Movements may be facilitated in some years by intensification of the relatively weak, residual currents (approximately 0.10 m/s) or by intensification of the moderately strong northwesterly winds in early summer. Two nests reported at Triangle Island off northern Vancouver Island in 1949 may have involved isolated pairs or a small remnant population, as breeding has not been reported since, or on surveys of colonies in June–July elsewhere on the northern coasts of Vancouver Island, from 1954 to 1988. These surveys, however, were too late for optimal detection of active nests of Ancient Murrelets, but no other signs of breeding were found. Surveys of potential habitat are required to confirm the lack of current breeding.

A coastwide bloom of the toxigenic diatom Pseudo‐nitzschia in spring 2015 resulted in the largest recorded outbreak of the neurotoxin, domoic acid, along the North American west coast. Elevated toxins were measured in numerous stranded marine mammals and resulted in geographically extensive and prolonged closures of razor clam, rock crab, and Dungeness crab fisheries. We demonstrate that this outbreak was initiated by anomalously warm ocean conditions. Pseudo‐nitzschia australis thrived north of its typical range in the warm, nutrient‐poor water that spanned the northeast Pacific in early 2015. The seasonal transition to upwelling provided the nutrients necessary for a large‐scale bloom; a series of spring storms delivered the bloom to the coast. Laboratory and field experiments confirming maximum growth rates with elevated temperatures and enhanced toxin production with nutrient enrichment, together with a retrospective analysis of toxic events, demonstrate the potential for similarly devastating ecological and economic disruptions in the future., Key Points The 2015 U.S. West Coast wide toxic Pseudo‐nitzschia australis bloom was facilitated by anomalous ocean conditionsThe seasonal transition to upwelling provided nutrients for the bloom, and spring storms delivered toxic cells to the nearshore environmentWest Coast toxic Pseudo‐nitzschia events are triggered by warm anomalies associated with El Niño and the Pacific Decadal Oscillation

The major (M w = 8.8) Chilean earthquake of 27 February 2010 generated a trans-oceanic tsunami that was observed throughout the Pacific Ocean. Waves associated with this event had features similar to those of the 1960 tsunami generated in the same region by the Great (M w = 9.5) 1960 Chilean Earthquake. Both tsunamis were clearly observed on the coast of British Columbia. The 1960 tsunami was measured by 17 analog pen-and-paper tide gauges, while the 2010 tsunami was measured by 11 modern digital coastal tide gauges, four NEPTUNE-Canada bottom pressure recorders located offshore from southern Vancouver Island, and two nearby open-ocean DART stations. The 2010 records were augmented by data from seven NOAA tide gauges on the coast of Washington State. This study examines the principal characteristics of the waves from the 2010 event (height, period, duration, and arrival and travel times) and compares these properties for the west coast of Canada with corresponding properties of the 1960 tsunami. Results show that the 2010 waves were approximately 3.5 times smaller than the 1960 waves and reached the British Columbia coast 1 h earlier. The maximum 2010 wave heights were observed at Port Alberni (98.4 cm) and Winter Harbour (68.3 cm); the observed periods ranged from 12 min at Port Hardy to 110–120 min at Prince Rupert and Port Alberni and 150 min at Bamfield. The open-ocean records had maximum wave heights of 6–11 cm and typical periods of 7 and 15 min. Coastal and open-ocean tsunami records revealed persistent oscillations that “rang” for 3–4 days. Tsunami energy occupied a broad band of periods from 3 to 300 min. Estimation of the inverse celerity vectors from cross-correlation analysis of the deep-sea tsunami records shows that the tsunami waves underwent refraction as they approached the coast of Vancouver Island with the direction of the incoming waves changing from an initial direction of 340° True to a direction of 15° True for the second train of waves that arrived 7 h later after possible reflection from the Marquesas and Hawaiian islands.

We present the first documented evidence of thermohaline staircases generated by double-diffusion in a coastal environment. Results are based on high (centimetre scale) resolution profiles of temperature, salinity and dissolved oxygen concentration collected on 20 July 2009 at seven stations along the axis of Belize Inlet on the mainland coast of British Columbia, Canada (Fig. 1). Except for stations nearest the narrow Pacific Ocean entrance to the inlet, the observed temperature and salinity gradients between 70 and 210 m depth were of the same sign, therefore conducive to double-diffusive phenomena. Thermohaline features were especially well developed near the head of the inlet. Salt-fingering staircases of approximately 10 m thickness were observed above the temperature and salinity minima at 150 m depth and diffusive-convection staircases of approximately 1 m thickness were observed below this depth. We speculate that conditions favourable to double diffusion were initiated by a mid-depth intrusion of...

Logistical challenges, time, and the cost of towed net surveys make it difficult to obtain estimates of secondary biomass and production in the open ocean outside the summer sampling season. Alternate approaches are sometimes needed. This study examines the relationship between biomass obtained from 197 mixed-species zooplankton net samples and proximate acoustic backscatter data collected over six summers, a depth range of 3,000 m, and a spatial scale of 200 km centered at a major hydrothermal region in the Northeast Pacific Ocean. Results show that the acoustic backscatter data from a single-frequency (150 kHz) acoustic Doppler current profiler mounted near the opening of the towed net system accounts for 84% of the variance in total net biomass, despite the remarkable mix of faunal types and depth range, and the broad spatial and temporal extent of the study. We discuss the potential reasons for the minor remaining variance in net biomass. The present findings demonstrate that profiling or moored acoustic backscatter instrumentation can provide a less-challenging methodology than net tows for obtaining bulk estimates of deep-sea zooplankton biomass in the open waters of the Northeast Pacific.

Record low returns of sockeye salmon Oncorhynchus nerka to the Fraser River in 2009 were followed by record high returns to the river in 2010, providing an unprecedented opportunity to examine links between oceanic factors and the survival of Pacific salmon stocks. The low returns in 2009 indicated poor early marine survival of juvenile sockeye salmon in 2007. The poor survival was likely due to low food levels arising from unfavorable wind and runoff conditions in the Strait of Georgia and the Queen Charlotte Sound–Hecate Strait region in the spring of 2007. Conversely, the high returns in 2010 were associated with a large smolt output from the Fraser River and good early marine survival in 2008. This enhanced survival was likely associated with adequate food levels arising from favorable oceanic conditions in the Strait of Georgia and the Queen Charlotte Sound–Hecate Strait region in the spring of 2008. We speculate that ocean factors during the subsequent marine years also affected brood year ...

The catastrophic Indian Ocean tsunami generated off the coast of Sumatra on 26 December 2004 was recorded by a large number of tide gauges throughout the World Ocean. This study uses gauge records from 173 sites to examine the characteristics and energy decay of the tsunami waves from this event in the Indian, Atlantic and Pacific oceans. Findings reveal that the decay (e-folding) time of the tsunami wave energy within a given oceanic basin is not uniform, as previously reported, but depends on the absorption characteristics of the shelf adjacent to the coastal observation site and the time for the waves to reach the site from the source region. In general, the decay times for island and open-ocean bottom stations are found to be shorter than for coastal mainland stations. Decay times for the 2004 Sumatra tsunami ranged from about 13 h for islands in the Indian Ocean to 40–45 h for mainland stations in the North Pacific.

There are few studies of the mechanistic links between physical environmental pro- cesses and biotic responses in marine ecosystems that have strong predictive power. At Triangle Island, the largest seabird colony along Canada's Pacific coast, annual breeding success of rhinoceros auklets Cerorhinca monocerata varies dramatically. Previous studies have correlated this variability with ocean temperature, but this relationship occasionally fails, suggesting that it is not causal. We used historical satellite data time series of sea surface temperature, chlorophyll, and winds to study the oceanography of this remote colony. We found that rhinoceros auklets bred more successfully when the spring transition in regional winds and the resulting spring phytoplankton bloom occurred early in April. These factors appear to control the annual recruitment of Pacific sandlance Ammodytes hexapterus, as measured by the percent by biomass of young-of-the-year sandlance in the nestling diet. These linkages imply bottom-up control in this system. Suggesting broader impli- cations of our work, we also found that marine survival of economically and culturally important sockeye salmon Oncorhynchus nerka from nearby Smith Inlet was strongly correlated with the fledg- ling mass of the rhinoceros auklets, sandlance in the chicks' diets, and regional chlorophyll in April. The timing of the spring wind transition and phytoplankton bloom appear to be important for other predators in this system. We think that these relationships with wind and chlorophyll derived from satellite data are potentially valuable explanatory tools that will be widely applicable to studies of early marine survival of many marine species.