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Map of the British Columbia continental shelf showing bathymetric contours, place names, and average positions of major offshore currents. The solid red line denotes the outer boundary of the regional shelf model; the solid green line shows the thalweg used in Fig. 4, and the solid dark blue lines denote the transects used in Figs 11 and 15.
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An ocean circulation model for the British Columbia continental shelf is run with future initial conditions and forcing fields downscaled from the North American Regional Climate Change Assessment Program archive. Average seasonal sea surface temperatures over the period of 2065-2078 are projected to increase by between 0.5 and 2.0°C with respect t...
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... 1995-2008 hindcast of water properties and flow fields along the BC continental shelf was recently carried out by Masson and Fine (2012). Their model is an application of the Regional Ocean Modeling System (ROMS; Haidvogel et al., 2008) with 3 km horizontal resolution, 30 sigma layers in the vertical, and the spatial coverage shown in Fig. 1. It employed Earth Topography 2-arc-min (ETOPO2) bathymetry with smoothing (maximum depth-gradient-to-depth ratio of 0.25) to reduce pressure gradient errors and was forced with tides, 3-hourly winds from the North American Regional Reanalysis (NARR; Mesinger et al., 2006), heat fluxes computed with standard bulk formulae and NARR ...
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... flow fields are described in Section 4, and Section 5 gives a short summary and outlines future work. Figure 2 shows seasonally averaged SST anomalies for the future period 2065 to 2078 with respect to their Masson and Fine (2012) counterparts. Though the model initial conditions were computed by adding latitude-dependent temperature anomalies ( Fig. 13 of Morrison et al., 2013) that ranged from about 1.5°C in the south to 1.8°C in the north to the Masson and Fine (2012) values in January 1995, the resultant 14-year average SST anomalies have a more complicated structure that reflects changes in the model forcing and circulation pat- terns (e.g., eddies). All seasonal SST anomalies ...
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... anomalies are generally the smallest. Even though the June-August river discharge temperatures have increased by a maximum of 2.5°C from those in Masson and Fine (2012), there are relatively small SST increases (approximately 0.3°C) around the mouths of the Fraser and Columbia rivers (not shown) because of decreases in the summer discharge ( Fig. 11 of Morrison et al., 2013). Note that the result for the Columbia River is somewhat artificial because much of its watershed is dammed and the actual river discharges at the mouth will be largely determined by the future release schedule of Bonne- ville Power, who operate the dam furthest downstream. Figure 3 shows seasonally averaged ...
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... averaged sea surface salinity (SSS) anomalies with respect to the Masson and Fine (2012) hindcast. Though here also, the model SSS initial condition anomalies were only latitude dependent, ranging from −0.25 in the south to −0.6 in the north, changes in the winds and cir- culation patterns arising from different monthly river dis- charges ( Fig. 11 of Morrison et al., 2013) have resulted in different seasonal SSS patterns. Though the generally smaller discharges from mid-June to mid-August resulted in higher near-shore salinities at a few locations and seasons, SSS values are generally lower over most of the model domain, consistent with an overall increase in precipitation. Some ...
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... anomaly emanating northwestward from Barkley Sound along the west coast of Vancouver Island and the positive winter anomaly in the Salish Sea, arise from changes in the spatial distribution of freshwater plumes under changing forcing. Figure 4 shows June contemporary salinities and future sal- inity anomalies along the Salish Sea thalweg (see Fig. 1 for location) during the annual peak Fraser River discharge. Con- sistent with the predicted increase in spring discharge (Fig. 11 of Morrison et al., 2013), the surface salinity along the transect decreases by about 0.75 and by up to 2.0 near the mouth of the Fraser River. Below the surface, the salinity in the Salish Sea is uniformly ...
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... the Salish Sea, arise from changes in the spatial distribution of freshwater plumes under changing forcing. Figure 4 shows June contemporary salinities and future sal- inity anomalies along the Salish Sea thalweg (see Fig. 1 for location) during the annual peak Fraser River discharge. Con- sistent with the predicted increase in spring discharge (Fig. 11 of Morrison et al., 2013), the surface salinity along the transect decreases by about 0.75 and by up to 2.0 near the mouth of the Fraser River. Below the surface, the salinity in the Salish Sea is uniformly reduced by about 0.5, with the general salinity signature of the estuarine circulation projected to remain almost unchanged. ...
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... understand this better, Fig. 5b shows future and contem- porary, summer and winter, σ t profiles at two sites lying along the transect off Vancouver Island shown in Fig. 1. Note that whereas the off-shelf site has profiles with relatively well- defined mixed-layer depths of approximately 45 m in winter and 30 m in summer, only the future winter profile at the shelf site has a hint of an inflection point (at about 35 m) that typically designates the bottom of the mixed layer. The other three profiles are ...
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... larger set-up from the stronger winter northwestward winds. The summer positive anomaly east of Cape St. James indicates a stronger clockwise circulation around Middle Bank which will be discussed later. Figure 7 shows contemporary and future bimonthly average SSHs at the ROMS grid cells nearest Vancouver, Victoria, Tofino, and Prince Rupert (Fig. 1). Figure 3 8 / M.G.G. Table 1. All ranges are seen to increase, with the largest increase being 7.3 cm at Prince Rupert; all the standard deviations are also seen to increase, suggesting larger interannual variability. Figure 7 and Table 1 also show mean sea levels (MSLs), and it is inter- esting to note that though there are no ...
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... is, therefore, important to place the SSH results for both the Masson and Fine (2012) and the future study periods in the context of these interdecadal variabilities. The average monthly value of the PDO over the 1995-2008 period of the Masson and Fine (2012) hindcast (see Mantua (2013) for a Figure 10 shows contemporary (from Fig. 4 of Masson & Fine, 2012) and future EKE along the BC continental shelf. ...
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... higher values off the west coast of Haida Gwaii ( Fig. 1) and northwest Vancouver Island are predominantly winter features that arise from stronger northwestward winds. Haida Eddies are generated when counter-clockwise flows around Hecate Strait exit past Cape St. James (Crawford, Cherniawsky, Foreman, & Gower, 2002;Di Lorenzo, Foreman, & Crawford, 2005); similar flow separation arises when ...
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... crossing a transect in southern Hecate Strait (see Fig. 1 for transect location) further illustrate the Haida Eddy generation mechanism and how it is projected to change in the future (Fig. 11). The average winter counter-clockwise cir- culation pattern is evident in the contemporary December- February panel with northwestward flows on the eastern side of the transect and southeastward flows ...
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... crossing a transect in southern Hecate Strait (see Fig. 1 for transect location) further illustrate the Haida Eddy generation mechanism and how it is projected to change in the future (Fig. 11). The average winter counter-clockwise cir- culation pattern is evident in the contemporary December- February panel with northwestward flows on the eastern side of the transect and southeastward flows on the western side. The future and anomaly panels for this same time period indi- cate an increase in both the northwestward and ...
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... therefore, reflect very local small-scale dynamics. Figure 11 shows similar but smaller flow anomalies in the September-November and March-May periods, suggesting that the eddy generation time period may be a little longer in the future. However, the March-May and June-August contemporary and future panels show that more complicated flow patterns arise when the winter winds weaken and reverse. ...
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... St. James, northwestward flows become restricted to the western side of the deep channel in the middle of the strait while a southeastward flow hugs the eastern side. The summer southeastward flows are seen to become slightly stron- ger in the future while the northwestward flows remain virtually unchanged. As seen in Fig. 1 and the depth profiles in Fig. 11, this transect misses the northern flank of Middle Bank and thus cannot provide any information on changes to the circulation around that bank. However, a similar transect (not shown) just to the south shows stronger northwestward flows down to 200 m depth on the western side of the bank in all seasons ...
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... James, northwestward flows become restricted to the western side of the deep channel in the middle of the strait while a southeastward flow hugs the eastern side. The summer southeastward flows are seen to become slightly stron- ger in the future while the northwestward flows remain virtually unchanged. As seen in Fig. 1 and the depth profiles in Fig. 11, this transect misses the northern flank of Middle Bank and thus cannot provide any information on changes to the circulation around that bank. However, a similar transect (not shown) just to the south shows stronger northwestward flows down to 200 m depth on the western side of the bank in all seasons and generally stronger ...
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... panel. Con- temporary and future salinity contours are generally flat and increase with depth over the western and central portions of the transect. These contours bend downward on the eastern side of the transect, largely as a result of freshwater discharges entering along the coast and northward flows coming from Queen Charlotte Sound (see Fig. 12). Though increases in these discharges result in consistently lower future salinities, wind direction seems to dictate the location of the largest anomalies. For example, the largest September-November salinity anomalies occur along the eastern shoreline, reflecting both an increase in freshwater discharge and northwestward winds. ...
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... of the largest anomalies. For example, the largest September-November salinity anomalies occur along the eastern shoreline, reflecting both an increase in freshwater discharge and northwestward winds. However, the largest anomalies in the June-August period occur in the central and western parts of the strait as dis- charges from the Skeena (Fig. 1) and other northern water- sheds are blown southward by stronger summer ...
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... future, and differences in the seasonally averaged, southern Hecate Strait flow fields at 20 m depth (Fig. 12) illustrate some of the patterns in Fig. 11 from a different perspective (20 m was chosen rather than the surface to reduce the effects of the wind). Stronger currents are seen along the western flank of Middle Bank in all seasons, and in the summer and fall they are accompanied by stronger flows on the eastern side, thereby ...
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... future, and differences in the seasonally averaged, southern Hecate Strait flow fields at 20 m depth (Fig. 12) illustrate some of the patterns in Fig. 11 from a different perspective (20 m was chosen rather than the surface to reduce the effects of the wind). Stronger currents are seen along the western flank of Middle Bank in all seasons, and in the summer and fall they are accompanied by stronger flows on the eastern side, thereby strengthening the clockwise eddy and producing the SSH ...
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... major summer current fea- tures seen in both Figs 11 and 12 have been observed and were described in Crawford, Woodward, Foreman, and Thomson (1995). Figure 13 shows analogous seasonally averaged 20 m flows in northern Hecate Strait and Dixon Entrance. Here the predo- minant patterns are the counter-clockwise Rose Spit Eddy (Crean, 1967) in Dixon Entrance and the northward flows along the eastern side of Hecate Strait. ...
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... northern edge of the eddy is seen to be an extension of the northward Hecate flows, which in turn largely arise from river discharges and the wind. Figure 14 shows analogous seasonally averaged 20 m flows in the Salish Sea and off the southwest Vancouver Fig. 11 Along-shelf currents crossing, and temperature (blue) and salinity (red) contours along, a transect off Cape St. James (Fig. 1). Redder (positive) shaded areas indicate greater flow to the northwest and the darker blue regions indicate greater flow to the southeast. ...
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... inten- sify in all seasons except summer, with the eddy position also varying seasonally. The northern edge of the eddy is seen to be an extension of the northward Hecate flows, which in turn largely arise from river discharges and the wind. Figure 14 shows analogous seasonally averaged 20 m flows in the Salish Sea and off the southwest Vancouver Fig. 11 Along-shelf currents crossing, and temperature (blue) and salinity (red) contours along, a transect off Cape St. James (Fig. 1). Redder (positive) shaded areas indicate greater flow to the northwest and the darker blue regions indicate greater flow to the ...
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... to be an extension of the northward Hecate flows, which in turn largely arise from river discharges and the wind. Figure 14 shows analogous seasonally averaged 20 m flows in the Salish Sea and off the southwest Vancouver Fig. 11 Along-shelf currents crossing, and temperature (blue) and salinity (red) contours along, a transect off Cape St. James (Fig. 1). Redder (positive) shaded areas indicate greater flow to the northwest and the darker blue regions indicate greater flow to the ...
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... & Hickey, 2010) and have important ecosystem impacts. However, unlike the more northerly Haida Eddies which move offshore after their generation, the Juan de Fuca Eddies are similar to the Middle and Goose Island Bank eddies and remain largely locked in place by underlying bathymetric features. Though the June-August anomaly panel in Fig. 14 does suggest a small increase in the current magnitudes around the periphery of the eddy, Fig. 10 (and magnifications that are not shown) suggests there is very little difference in the future EKE in this region. Fig. 12 Contemporary (1995-2008, future ...
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... Haida Eddies which move offshore after their generation, the Juan de Fuca Eddies are similar to the Middle and Goose Island Bank eddies and remain largely locked in place by underlying bathymetric features. Though the June-August anomaly panel in Fig. 14 does suggest a small increase in the current magnitudes around the periphery of the eddy, Fig. 10 (and magnifications that are not shown) suggests there is very little difference in the future EKE in this region. Fig. 12 Contemporary (1995-2008, future (2065)(2066)(2067)(2068)(2069)(2070)(2071)(2072)(2073)(2074)(2075)(2076)(2077)(2078), and differences in seasonally averaged currents at 20 m depth in Queen Charlotte Sound. Note the ...
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... were any changes in these timings and, perhaps not surprisingly, given the lack of change in the winds described in Morrison et al. (2013), none were found. So unlike the more northerly eddies described above, our future simulations do not suggest any significant changes to future Juan de Fuca Eddies. However the June-August anomaly panel in Fig. 14 does show a stronger Vancouver Island Coastal Current (VICC; Thomson, Hickey, & LeBlond, 1989) arising from the stron- ger surface estuarine flows in Juan de Fuca Strait. The Shelf Break Current (SBC; Freeland et al., 1984) arising from upwelling winds is also evident in the June-August and Sep- tember-November contemporary and future ...
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... Shelf Break Current (SBC; Freeland et al., 1984) arising from upwelling winds is also evident in the June-August and Sep- tember-November contemporary and future panels, and though the associated anomalies suggest magnitude increases, the patterns are not sufficiently distinct from those of the Juan de Fuca Eddy and an offshore eddy to permit definitive conclusions. Figure 15a shows contemporary and future seasonal along- shore currents, isotherms, and isohalines along a transect crossing the mid-Vancouver Island shelf. There are five main currents in this region, four of which are seen in the June-August contemporary and future panels. ...
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... The atmospheric pressure systems, the Aleutian Low and the North Pacific High, generate the northward Alaska Current and southward California Current. The locations of these pressure systems vary seasonally: in summer, the transition zone between these currents is further north and the California Current is positioned off the WCVI; in winter, the transition zone is further south (Foreman et al., 2014;Thomson, 1981). The direction of the geostrophic surface current along the shelf break also changes seasonally: in summer, northwesterly winds drive a shelf-break current to the southeast, generating upwelling conditions; in winter, southeasterly winds drive a shelf-break current, the Davidson Current, to the northwest generating downwelling conditions (Crawford & Thomson, 1991;Foreman et al., 2014;Thomson, 1981). ...
... The locations of these pressure systems vary seasonally: in summer, the transition zone between these currents is further north and the California Current is positioned off the WCVI; in winter, the transition zone is further south (Foreman et al., 2014;Thomson, 1981). The direction of the geostrophic surface current along the shelf break also changes seasonally: in summer, northwesterly winds drive a shelf-break current to the southeast, generating upwelling conditions; in winter, southeasterly winds drive a shelf-break current, the Davidson Current, to the northwest generating downwelling conditions (Crawford & Thomson, 1991;Foreman et al., 2014;Thomson, 1981). These geostrophic shelf-break currents can interact with canyon bathymetry generating canyon upwelling or downwelling. ...
... Of course, other mechanisms distinct from canyon downwelling and water mass composition may have played a role in influencing zooplankton distributions in this study. First, several mechanisms distinct from canyon processes can cause variability in the pycnocline depth and thus, given the documented correlation between pycnocline depth and zooplankton S v (Figure 5c, (Battisti & Hickey, 1984;Sobarzo et al., 2016), and storm-induced mixing (Crawford & Dewey, 1989;Foreman et al., 2014) all may generate changes in pycnocline depth and, consequently, influence zooplankton distributions. Although analysis of the Bakun upwelling index (Schwing et al., 1996) and sea level data (Caldwell et al., 2015) relevant to the study period and region did not suggest mechanisms to explain the observed low-frequency variability in pycnocline depth (not shown), we note that the observed pycnocline shoaling was coincident with a storm that occurred February 9-10 (Figures 2a and 2b). ...
Submarine canyons are considered biological hotspots due to enhanced mixing, upwelling, and other dynamic processes. There have been few observational surveys of canyon processes or zooplankton‐watermass relations during stormy downwelling seasons. In winter 2017, three autonomous underwater gliders provided highly‐resolved hydrographic and zooplankton backscatter observations in and around a canyon in the Northeast Pacific. While a glider's slow speed typically confounds spatial and temporal signals, the concurrent use of multiple gliders, sampling a canyon transect repeatedly, allowed us to explore the canyon system both spatially (i.e., canyon influence) and temporally (i.e., changing water type fractions). Canyon downwelling displaced the pycnocline by about 30 m depth over the scale of the canyon, which is ∼30% of the total pycnocline depth deviation observed over the course of the study. Diel vertically migrating (DVM) zooplankton generally stayed above the pycnocline and mean zooplankton volume scattering strength (Sv) in the upper water column (above the pycnocline) was higher when the pycnocline was deeper. At mid‐depths (150–200 m depth), zooplankton backscatter and DVM behavior were correlated with water type fractions, with higher Sv being associated with higher proportions of Pacific Equatorial Water and stronger DVM being associated with higher proportions of Pacific Subarctic Upper Water. Winter zooplankton distributions appear to be influenced by multiple, interacting drivers including canyon dynamics and water mass composition. In our study, the latter was found to have the stronger influence on zooplankton distribution.
... Going forward, this will require development of downscaled forecasts of circulation dynamics across geographical regions (e.g. [80,81]), demanding collaborations between physical oceanographers and marine evolutionary ecologists. ...
As climate change threatens species' persistence, predicting the potential for species to adapt to rapidly changing environments is imperative for the development of effective conservation strategies. Eco-evolutionary individual-based models (IBMs) can be useful tools for achieving this objective. We performed a literature review to identify studies that apply these tools in marine systems. Our survey suggested that this is an emerging area of research fuelled in part by developments in modelling frameworks that allow simulation of increasingly complex ecological, genetic and demographic processes. The studies we identified illustrate the promise of this approach and advance our understanding of the capacity for adaptation to outpace climate change. These studies also identify limitations of current models and opportunities for further development. We discuss three main topics that emerged across studies: (i) effects of genetic architecture and non-genetic responses on adaptive potential; (ii) capacity for gene flow to facilitate rapid adaptation; and (iii) impacts of multiple stressors on persistence. Finally, we demonstrate the approach using simple simulations and provide a framework for users to explore eco-evolutionary IBMs as tools for understanding adaptation in changing seas.
... The challenge of designing connected MPA networks increases when the objective is to protect multiple species (Magris et al. 2016;D'Aloia et al. 2017) that have different habitat requirements and dispersal abilities since the appropriate sizing and spacing of MPAs will differ among species (Gerber et al. 2003). Additionally, connectivity may shift in the future as a result of changing oceanographic conditions due to climate change (IPPC 2014;Foreman et al. 2014) and shifting species traits 1 3 (O'Connor et al. 2007), thus the MPA network configuration that is optimal today may be suboptimal in the future (Levy and Ban 2013). ...
... We then use the spatial conservation prioritization software Marxan ) to predict which areas are most important to conserve in a connected MPA network. We also apply a climate-change forecast (Nakicenovic et al. 2000;Foreman et al. 2014) to predict how increasing ocean temperature and shifts in species dispersal will alter optimal MPA network configuration in the future. ...
Marine Protected Areas (MPAs) are areas of marine ecosystems that have some level of protection to support one or more conservation objectives. One characteristic of MPA networks is that MPAs are spatially configured such that they provide the greatest protection possible for multiple species. Yet, it can be difficult to determine optimal MPA network arrangement due to insufficient information on multi-species habitat use and their dispersal abilities as larvae and adults. Here, we propose a modelling approach that involves determining the optimal MPA network configuration for multiple species assemblages, located at different depths and having differing dispersal abilities. As a case study, we applied this methodology in Pacific Canada where we identified optimal MPA configurations to protect 40 species having different pelagic larval duration (proxy for dispersal) at 3 different depth class groupings (proxy for habitat use). Taken together, we found dispersal ability had a larger impact on optimal MPA network configuration for species spending a long time as larvae compared to species spending a short time as larvae. We identify which 10% of this area is most important to conserve to maintain connectivity for a multi-species MPA network and show that half of these sites remain important to conserve in the future as climate change alters connectivity patterns. This model for MPA network design is feasible with limited data which is beneficial for application to other regions and ecosystems.
... To forecast ocean currents over the 10-year period from 2068 to 2077, Morrison et al. (2014) computed initial and forcing conditions using Canadian global climate model 3 (CGCM3) with the Canadian regional climate model (CRCM). The expected changes derived from this model are an increase in sea surface temperature, increase in sea surface levels, and stronger currents due to fluvial outflows (Foreman et al. 2014). The changes in ocean circulation due to these changes represent our abiotic effect (Table 1). ...
Climate change is having multiple impacts on marine species characterized by sedentary adult and pelagic larval phases, from increasing adult mortality to changes in larval duration and ocean currents. Recent studies have shown impacts of climate change on species persistence through direct effects on individual survival and development, but few have considered the indirect effects mediated by ocean currents and species traits such as pelagic larval duration. We used a density‐dependent and stochastic metapopulation model to predict how changes in adult mortality and dynamic connectivity can affect marine metapopulation stability. We analyzed our model with connectivity data simulated from a biophysical ocean model of the northeast Pacific coast forced under current (1998–2007) and future (2068–2077) climate scenarios in combination with scenarios of increasing adult mortality and decreasing larval duration. Our results predict that changes of ocean currents and larval duration mediated by climate change interact in complex and opposing directions to shape local mortality and metapopulation connectivity with synergistic effects on regional metapopulation stability: while species with short larval duration are most sensitive to temperature‐driven reduction in larval duration, the response of species with longer larval duration are mostly mediated by changes in both the mean and variance of larval connectivity driven by ocean currents. Our results emphasize the importance of considering the spatiotemporal structure of connectivity in order to predict how the multiple effects of climate change will impact marine populations.
... Rising temperature, acidification, and declining oxygen are three important stressors that affect marine biodiversity and ecosystem health both individually and synergistically (Gruber, 2011;Pörtner et al., 2014). Climate change may also result in changes to the upwelling-and downwelling-favorable winds that play a major role in the oceanography of the Canadian Pacific continental margin (Merryfield et al., 2009;Foreman et al., 2014). Episodes of extremely hypoxic or corrosive water have already led to extensive die offs of marine life in the region (Barton et al., 2015;Chan et al., 2019). ...
... We present here a high-resolution regional projection of future climate for the Canadian Pacific continental margin. The point of departure for this work is Foreman et al. (2014) which examined changes in the physical oceanography of the British Columbia (BC) Continental Shelf. Our model includes biogeochemistry, has a higher resolution and uses an approach to dynamically downscaling climate projections that reduces computational costs. ...
... River runoff was defined according to Morrison et al. (2012) and the concentrations of dissolved inorganic carbon and total alkalinity in river water were set to 10 −3 mol/L. Similar to Foreman et al. (2014), future initial conditions and OBC were constructed using the Pseudo-Global-Warming method (Hara et al., 2008;Morrison et al., 2012) by adding a monthly anomaly generated from CanESM2 (Arora et al., 2011) to the historical fields. CanESM2 has a 1 − 2 • horizontal resolution with 40 vertical levels and uses the Canadian Model of Ocean Carbon (CMOC) which is a precursor to CanOE with 6 passive tracers. ...
Model projections of ocean circulation and biogeochemistry are used to investigate large scale climate changes under moderate mitigation (RCP 4.5) and high emissions (RCP 8.5) scenarios along the continental shelf of the Canadian Pacific Coast. To reduce computational cost, an approach for dynamical downscaling of climate projections was developed that uses atmospheric climatologies with augmented winds to simulate historical (1986–2005) and future (2046–2065) periods separately. The two simulations differ in initial and lateral open boundary conditions. For each simulation, the daily climatology of surface winds in the driving model was augmented with high-frequency variability from an atmospheric reanalysis product. The “time-slice” approach was able to reproduce the observed climate state for the historical period. Sensitivity tests confirmed that the high frequency wind variability plays an essential role in freshwater distribution in this region. Projections suggest that sea surface temperature will increase by 1.8–2.4°C and surface salinity will decrease between −0.08 and −0.23 depending on whether a moderate or high emissions scenario is used. Stratification increases throughout the region and there is some evidence of nutrient limitation near the surface. Primary production and phytoplankton productivity (chlorophyll) also increase. Density surfaces are relocated deeper in the water column and this change is mainly driven by surface heating and freshening. Changes in saturation state are mainly due to anthropogenic CO2 with minor contributions from solubility, remineralization and advection. There is little difference between RCP 4.5 and RCP 8.5 with regard to projections of deoxygenation and acidification. The depths of the aragonite saturation state and the oxygen minimum zone are projected to become shallower by ≃ 100 and ≃ 75 m respectively. Extreme states of temperature, oxygen and acidification are projected to become more frequent and more extreme, with the frequency of occurrence of [O2]<60 mmolm-3 expected to approximately double under either scenario.
... To forecast ocean currents over the 10-year period from 2068 to 2077, Morrison et al. (2014) computed initial and forcing conditions using Canadian Global Climate Model 3 (CGCM3) with the Canadian Regional Climate Model (CRCM). The expected changes derived from this model are an increase in sea surface temperature, increase in sea surface levels, and stronger currents due to fluvial outflows (Foreman et al. 2014). The changes in ocean circulation due to these changes represent our abiotic effect ( Table 1). ...
Climate change is having multiple impacts on marine species characterized by sedentary adult and pelagic larval phases, from increasing adult mortality to changes in larval duration and ocean currents. Recent studies have shown impacts of climate change on species persistence through direct effects on individual survival and development, but few have considered the indirect effects mediated by ocean currents and species traits such as pelagic larval duration. We used a density-dependent and stochastic metapopulation model to predict how changes in adult mortality and dynamic connectivity can affect marine metapopulation stability. We analyzed our model with connectivity data simulated from a biophysical ocean model of the northeast Pacific coast forced under current (1998-2007) and future (2068-2077) climate scenarios in combination with scenarios of increasing adult mortality and decreasing larval duration. Our results predict that changes of ocean currents and larval duration mediated by climate change interact in complex and opposing directions to shape local mortality and metapopulation connectivity with synergistic effects on regional metapopulation stability: while species with short larval duration are most sensitive to temperature-driven reduction in larval duration, the response of species with longer larval duration are mostly mediated by changes in both the mean and variance of larval connectivity driven by ocean currents. Our results emphasize the importance of considering the spatiotemporal structure of connectivity in order to predict how the multiple effects of climate change will impact marine populations.
... We calculated heterozygosity and local F ST with the 51 candidate SNPs as metrics of adaptive genetic diversity and distinctness (H adapt and F STadapt , respectively) ( Table 1). We computed two additional metrics based on the assumption that alleles positively associated with bottom temperature are considered adaptive because ocean temperature in the region is predicted to increase (Foreman et al. 2014). The first is the population adaptive index (PAI), which reflects the uniqueness of adaptive genomic diversity in one site compared with all other sites (Bonin et al. 2009; Table 1). ...
The availability of genomic data for an increasing number of species makes it possible to incorporate evolutionary processes into conservation plans. Recent studies show how genetic data can inform spatial conservation prioritization (SCP), but they focus on metrics of diversity and distinctness derived primarily from neutral genetic data sets. Identifying adaptive genetic markers can provide important information regarding the capacity for populations to adapt to environmental change. Yet, the effect of including metrics based on adaptive genomic data into SCP in comparison to more widely used neutral genetic metrics has not been explored. We used existing genomic data on a commercially exploited species, the giant California sea cucumber (Parastichopus californicus), to perform SCP for the coastal region of British Columbia (BC), Canada. Using a RAD‐seq data set for 717 P. californicus individuals across 24 sampling locations, we identified putatively adaptive (i.e., candidate) single nucleotide polymorphisms (SNPs) based on genotype–environment associations with seafloor temperature. We calculated various metrics for both neutral and candidate SNPs and compared SCP outcomes with independent metrics and combinations of metrics. Priority areas varied depending on whether neutral or candidate SNPs were used and on the specific metric used. For example, targeting sites with a high frequency of warm‐temperature‐associated alleles to support persistence under future warming prioritized areas in the southern coastal region. In contrast, targeting sites with high expected heterozygosity at candidate loci to support persistence under future environmental uncertainty prioritized areas in the north. When combining metrics, all scenarios generated intermediate solutions, protecting sites that span latitudinal and thermal gradients. Our results demonstrate that distinguishing between neutral and adaptive markers can affect conservation solutions and emphasize the importance of defining objectives when choosing among various genomic metrics for SCP.
... We estimated thermal limits for the adult life stage of selected species using two methods: extracting data from a physiological limits database (Steiner et al. 2018) and outputs of a Bayesian hierarchical species distribution model (McMillan et al. in review). Average seasonal thermal change was determined from the difference between contemporary (Masson and Fine 2012) and projected (Foreman et al. 2014; A2 (no abatement), AR4; 2060-70s) regional ocean model systems models (ROMS). The difference in temperature between time periods and across fishing footprints relative to each species thermal threshold was translated into an exposure index that accounted for the change in: 1) extent (entire fishing footprint), 2) magnitude (proportion of footprint with threshold met or exceeded), 3) frequency of threshold being met or exceeded, and 4) degree of threshold exceedance relative to each species' threshold ( Figure 55-1). ...
Report is on page 194-198.
In Saanich Inlet, biologically-relevant hypoxia exposure could not be calculated for the first time since ONC-VENUS monitoring began because of a 4-month data gap in the ONC-VENUS array, but appears synoptically similar to 2018.
Density of commercial shrimp (e.g. Spot Prawn Pandalus platyceros) has recovered to the benchmark period.
Sustained, low-level populations of new species (Armina californica and Pentamera cf. pseudocalcigera) remain in the community.
Recruitment of Sea Whip (Halipteris willemoesi) is the first indication of their potential to recover after a severe hypoxia-induced population crash, although they are still <8% of the population that existed before the benchmark period (2006-2013).
Recovery rate of the cold-water corals is substantially slower than the recovery of the habitat oxygen regime and the mobile species assemblage which have mostly returned to levels comparable to the benchmark period (2006-2013).
... On the other side, the southern region shows an increase of up to 0.56°C per decade 1 (1973-2010), which is expected to rise by 3°C by the end of the 21st century [36]. In general, simulation of future oceanic conditions estimates that the average seasonal SSTs along the continental shelf of BC are predicted to increase between 0.5 and 2.0°C for the period 2065-2078 [37]. ...
Global warming is already affecting the oceans through changes in water temperature, acidification, oxygen content and sea level rise, amongst many others. These changes are having multiple effects on marine species worldwide, with subsequent impacts on marine fisheries, peoples' livelihoods and food security. This work presents a review of the recent literature on the current and projected impacts of climate change on Canada's Pacific marine ecosystem. We find that there is an increasing number of studies in British Columbia focusing on changes in ocean conditions and marine species responses under climate change, including an emerging literature on the socio-economic impacts of these changes considered to be a knowledge gap. According to the literature, it is well established that ocean temperatures are increasing over the long-term, especially, in southern areas of British Columbia. Warming trends are increasing in the spring and are strongest in summer. However, there are important uncertainties regarding other climate drivers, such as oxygen concentration and acidification, stemming mainly from the insufficiency of data. Pacific salmon, elasmobranchs, invertebrates and rockfishes are amongst the most vulnerable species groups to climate change in British Columbia. Also, shifts in stock distribution and fish abundance under climate change may have a significant impact on fish supply affecting the livelihoods and food security of some British Columbians. The magnitude of these impacts is likely to vary according to a latitudinal gradient, with southern coastal areas being more affected than northern and central areas; challenging multiple areas of governance, such as equity and fishing access amongst First Nations; and institutional arrangements for transboundary stocks between the U.S. and Canada.
... This can also have important implications for prioritizing sites for protection, where the level of adaptive genetic variation could be an indicator of the evolutionary resilience of populations (Bonin, Nicole, Pompanon, Miaud, & Taberlet, 2007;Sgrò, Lowe, & Hoffmann, 2011). In the coastal region of the northeastern Pacific, temperature and heat content are predicted to increase (Abraham et al., 2013;Foreman et al., 2014) and salinity is predicted to decrease Morrison et al., 2014) in the future. As such, the spatial patterns of genetic variability observed in this study can inform conservation planning decisions by identifying for protection populations containing higher levels of segregating polymorphisms associated with environmental conditions (e.g., temperature and salinity) that are prone to change in the future. ...
Understanding the spatial scale of local adaptation and the factors associated with adaptive diversity are important objectives for ecology and evolutionary biology, and have significant implications for effective conservation and management of wild populations and natural resources. In this study, we used an environmental association analysis (EAA) to identify important bioclimatic variables correlated with putatively adaptive genetic variation in a benthic marine invertebrate – the giant California sea cucumber (Parastichopus californicus) – spanning coastal British Columbia and southeastern Alaska. We used a redundancy analysis (RDA) with 3,699 SNPs obtained using RAD sequencing to detect candidate markers associated with 11 bioclimatic variables, including sea bottom and surface conditions, across two spatial scales (entire study area and within sub‐regions). At the broadest scale, RDA revealed 59 candidate SNPs, 86% of which were associated with mean bottom temperature. Similar patterns were identified when population structure was accounted for. Additive polygenic scores, which provide a measure of the cumulative signal across all candidate SNPs, were strongly correlated with mean bottom temperature, consistent with spatially varying selection across a thermal gradient. At a finer scale, 23 candidate SNPs were detected, primarily associated with surface salinity (26%) and bottom current velocity (17%). Our findings suggest that environmental variables may play a role as drivers of spatially varying selection for P. californicus. These results provide context for future studies to evaluate the genetic basis of local adaptation in P. californicus and help inform the relevant scales and environmental variables for in situ field studies of putative adaptive variation in marine invertebrates.
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