Bedford Institute of Oceanography
Dartmouth, Canada

The Bedford Institute of Oceanography is a major Government of Canada ocean research facility located in Dartmouth, Nova Scotia. BIO is the largest ocean research station in Canada. Established in 1962 as Canada's first, and currently largest, federal centre for oceanographic research, BIO derives its name from the Bedford Basin, an inland bay comprising the northern part of Halifax Harbour, upon which it is located.Spread out over 40 acres of a former Royal Canadian Navy property near Shannon Park in Dartmouth, BIO consists of a series of interconnected buildings housing research labs and offices, as well as docks for Canadian Coast Guard and RCN research vessels.As the federal government seeks to concentrate its operations in the Halifax Regional Municipality, BIO is being considered for additional office buildings to house other non-oceanographic and non-research organizations and their employees. As such, new buildings have been built for the Canadian Coast Guard as well as Environment Canada in recent years. Wikipedia.

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News Article | May 27, 2017

Canadian researchers have discovered a new species of meat-eating sponge in the North Atlantic Ocean. Don’t worry, though, it doesn’t eat human meat — it feeds on zooplankton, tiny animals that drift in sea water. (With those fish bone-looking spikes, though, it sure looks like a creature from hell.) The carnivorous sponge, named Cladorhiza kenchingtonae after Canadian research scientist Ellen Kenchington, is about 6.5 feet long. Its surface is covered in “microscopic hook-like glass spicules” that give the sea creature “a Velcro like surface,” according to a press release by Fisheries and Oceans Canada. Though the discovery was announced this week, the sponge was actually found in 2010 by Kenchington and other researchers at the Bedford Institute of Oceanography, during a research trip on the Canadian Coast Guard Ship Hudson. The researchers weren’t actively looking for new species, but when the Remotely Operated Vehicle spotted the sponge, the scientists on board the Hudson realized they’d never seen it before and collected a sample. The sponge has been studied since then and will be described in a study coming out this summer. Our oceans are populated by thousands of sponge species. Usually, these sea creatures just passively filter sea water for nutrients. But some species like to feed on meat. In 2014, scientists discovered four species of killer sponges off the coast of California, nearby undersea volcanoes and deep-sea vents. These carnivorous sponges use hooks to trap tiny crustaceans. The new species was found at a depth of 1.8 miles underneath the sea surface, which means you’ll never stumble upon it during a swim. Thank god.

In nearshore ecosystems, habitats with emergent structure are often assumed to have higher ecosystem functioning than habitats lacking structure. However, such habitat-specific differences may depend on the surrounding environment. In this study, I examine the robustness of habitat-specific differences in ecosystem functioning for seagrass (Zostera marina) and adjacent bare soft sediments across varying environmental conditions on the Atlantic Coast of Nova Scotia, Canada, using secondary production as a metric. I also examine relationships of community secondary production and faunal structure with measured environmental variables (water depth, temperature, exposure, sediment, and plant properties). Benthic secondary production (invertebrates ≥500 μm) was higher in seagrass compared to bare sediments only at exposed sites with sandy sediments low in organic content, deep and cool water, and high belowground plant biomass. A regression relating community secondary production to the environmental variables explained 56% of the variance, while a constrained ordination explained 16% of the community structure. Important environmental determinants of community production were shoot density, temperature, depth, exposure, sediment organic content, and belowground plant biomass. Community structure was influenced by these variables plus sediment sand content and canopy height. This study shows that habitat-specific differences in secondary production may not be consistent across varying environmental conditions. Furthermore, seagrass beds are not always associated with higher ecosystem functioning than adjacent bare sediment. Both the surrounding environmental conditions and the presence of habitat structure should be considered for optimal management of nearshore ecosystems. © 2017 Her Majesty the Queen in right of Canada as represented by Fisheries and Oceans Canada

Kieke D.,University of Bremen | Yashayaev I.,Bedford Institute of Oceanography
Progress in Oceanography | Year: 2015

Labrador Sea Water (LSW), the lightest contribution to North Atlantic Deep Water (NADW) and one of the most prominent water masses of the subpolar North Atlantic, has seen remarkable changes over the past century. LSW originates in the Labrador Sea, where it is formed through wintertime ocean convection of varying intensity, depth and spatial extent. Formation of LSW, followed by its respective injection into the mid-depth circulation system, is mandatory for ventilating and renewing water layers of the interior ocean. Indispensably important for unraveling the history of variability in formation and properties of LSW as well as for mapping its large-scale spreading and export are sustained physical and chemical observations from the deep ocean. These observations started at the beginning of the 20th century from occasional mostly national surveys and today constitute large-scale multi-national collaborative efforts including a vast arsenal of sophisticated instrumentation. In a historical context, we revisit major milestones over the past 100. years which have established and are constantly adding to shaping today's knowledge on LSW, and present first details on the latest vintage of LSW generated during the strong winter of 2013/2014. Respective Argo data reveal mixed-layer depths greater than 1700. m marking formation of a new cold and fresh anomaly that has spread since then over the subpolar North Atlantic. We further summarize the on-going observational efforts in the subpolar North Atlantic and present a compilation of hydrographic standard lines that serve to provide top-to-bottom information on NADW components. © 2014 Elsevier Ltd.

Talling P.J.,UK National Oceanography Center | Paull C.K.,Monterey Bay Aquarium Research Institute | Piper D.J.W.,Bedford Institute of Oceanography
Earth-Science Reviews | Year: 2013

Subaqueous sediment density flows are one of the volumetrically most important processes for moving sediment across our planet, and form the largest sediment accumulations on Earth (submarine fans). They are also arguably the most sparely monitored major sediment transport processes on our planet. Significant advances have been made in documenting their timing and triggers, especially within submarine canyons and delta-fronts, and freshwater lakes and reservoirs, but the sediment concentration of flows that run out beyond the continental slope has never been measured directly. This limited amount of monitoring data contrasts sharply with other major types of sediment flow, such as river systems, and ensure that understanding submarine sediment density flows remains a major challenge for Earth science. The available monitoring data define a series of flow types whose character and deposits differ significantly. Large (>100km3) failures on the continental slope can generate fast-moving (up to 19m/s) flows that reach the deep ocean, and deposit thick layers of sand across submarine fans. Even small volume (0.008km3) canyon head failures can sometimes generate channelised flows that travel at >5m/s for several hundred kilometres. A single event off SE Taiwan shows that river floods can generate powerful flows that reach the deep ocean, in this case triggered by failure of recently deposited sediment in the canyon head. Direct monitoring evidence of powerful oceanic flows produced by plunging hyperpycnal flood water is lacking, although this process has produced shorter and weaker oceanic flows. Numerous flows can occur each year on river-fed delta fronts, where they can generate up-slope migrating crescentic bedforms. These flows tend to occur during the flood season, but are not necessarily associated with individual flood discharge peaks, suggesting that they are often triggered by delta-front slope failures. Powerful flows occur several times each year in canyons fed by sand from the shelf, associated with strong wave action. These flows can also generate up-slope migrating crescentic bedforms that most likely originate due to retrogressive breaching associated with a dense near-bed layer of sediment. Expanded dilute flows that are supercritical and fully turbulent are also triggered by wave action in canyons. Sediment density flows in lakes and reservoirs generated by plunging river flood water have been monitored in much greater detail. They are typically very dilute (<0.01vol.% sediment) and travel at <50cm/s, and are prone to generating interflows within the density stratified freshwater. A key objective for future work is to develop measurement techniques for seeing through overlying dilute clouds of sediment, to determine whether dense near-bed layers are present. There is also a need to combine monitoring of flows with detailed analyses of flow deposits, in order to understand how flows are recorded in the rock record. Finally, a source-to-sink approach is needed because the character of submarine flows can change significantly along their flow path. © 2013 Elsevier B.V.

Frank K.T.,Bedford Institute of Oceanography | Petrie B.,Bedford Institute of Oceanography | Fisher J.A.D.,Queen's University | Leggett W.C.,Queen's University
Nature | Year: 2011

Overfishing of large-bodied benthic fishes and their subsequent population collapses on the Scotian Shelf of Canada's east coast and elsewhere resulted in restructuring of entire food webs now dominated by planktivorous, forage fish species and macroinvertebrates. Despite the imposition of strict management measures in force since the early 1990s, the Scotian Shelf ecosystem has not reverted back to its former structure. Here we provide evidence of the transient nature of this ecosystem and its current return path towards benthic fish species domination. The prolonged duration of the altered food web, and its current recovery, was and is being governed by the oscillatory, runaway consumption dynamics of the forage fish complex. These erupting forage species, which reached biomass levels 900% greater than those prevalent during the pre-collapse years of large benthic predators, are now in decline, having outstripped their zooplankton food supply. This dampening, and the associated reduction in the intensity of predation, was accompanied by lagged increases in species abundances at both lower and higher trophic levels, first witnessed in zooplankton and then in large-bodied predators, all consistent with a return towards the earlier ecosystem structure. We conclude that the reversibility of perturbed ecosystems can occur and that this bodes well for other collapsed fisheries. © 2011 Macmillan Publishers Limited. All rights reserved.

Although many studies have examined foraging success across seagrass complexity, few have identified underlying behavioural mechanisms or examined effects of belowground complexity. Here, I used a new habitat complexity index ( IBG), behavioural data, and laboratory manipulations of artificial above- and belowground structures and predator sizes to understand foraging of invasive green crabs ( Carcinus maenas) on soft-shell clams ( Mya arenaria) in seagrass ( Zostera marina) beds. IBG was calculated as interstitial area between rhizomes (i.e., belowground complexity) divided by claw area; belowground complexity was varied while claw area was held constant. This meant that as IBG increased, belowground complexity itself decreased. Belowground complexity strongly affected crab foraging, and a sigmoid function described predation rate across increasing IBG. This relationship was not evident when aboveground complexity was high (i.e., interstitial area between shoots was small), and no patterns in predation across a gradient of aboveground complexity were observed. Important behavioural mechanisms included encounter rate with prey and the probability of capture upon encounter, both of which increased hyperbolically as IBG increased, and handling time per prey, which decreased exponentially as IBG increased. Most handling time was spent excavating prey from the sediments. Predator size did not change these relationships, although larger crabs had more difficulty capturing prey at low IBG than smaller crabs. Clearly, success of crabs feeding on infauna in seagrass beds is limited most by claw size relative to opening size from which prey are extracted. IBG incorporates this limitation, and can be used to predict effects of habitat complexity on foraging success of epibenthic predators in various habitat types. © 2013.

Kenchington T.J.,Bedford Institute of Oceanography
Fish and Fisheries | Year: 2014

The 29 estimators of natural mortality (M) that have been proposed for 'information-limited' fisheries are reviewed, together with a new alternative presented here. Each is applied to 13 example populations for which well-founded estimates are available of both M and the estimators' parameters. None of the 30 can provide accurate estimates for every species, and none appears sufficiently precise for use in analytical stock assessments, while several perform so poorly as to have no practical utility. If the growth coefficient K has been reliably estimated, either M = 1.5 K or Pauly's long-established estimator can provide useful estimates of M, but they fail with species that have long adult lives after swift juvenile growth, with those that never reach their asymptotic lengths and with species that otherwise deviate from archetypal teleost life histories. If a pre-exploitation maximum observed age (Tmax) can be established, M can be estimated for both teleosts and sharks using M = 4.3/Tmax but that seriously underestimates when the effective sample size (ne) is large and overestimates with species showing pronounced senescence. The new estimator presented here addresses ne but is upset by even mild senescence. Some estimators of M-at-size, particularly ones recently advanced by Gislason et al. and Charnov et al., also show promise but require further examination. It is recommended that fisheries scientists measure M by more advanced methods whenever possible. If 'information-limited' estimators must be used, their uncertainties should be acknowledged and their errors propagated into management advice. © Her Majesty the Queen in Right of Canada 2013.

Mosher D.C.,Bedford Institute of Oceanography
Marine and Petroleum Geology | Year: 2011

It is the intent of this paper to explore a significant extent of an entire passive continental margin for hydrate occurrence to understand hydrate modes of occurrence, preferred geologic settings and estimate potential volumes of methane. The presence of gas hydrates offshore of eastern Canada has long been inferred from estimated stability zone calculations, but little physical evidence has been offered. An extensive set of 2-D and 3-D, single and multi-channel seismic reflection data comprising in excess of 140,000 line-km was analyzed. Bottom simulating reflections (BSR) were unequivocally identified at seven sites, ranging between 250 and 445 m below the seafloor and in water depths of 620-2850 m. The combined area of the BSRs is 9311 km2, which comprises a small proportion of the entire theoretical stability zone along the Canadian Atlantic margin (∼715,165 km2). The BSR within at least six of these sites lies in a sedimentary drift deposit or sediment wave field, indicating the likelihood of grain sorting and potential porosity and permeability (reservoir) development. Although there are a variety of conditions required to generate and recognize a BSR, one might assume that these sites offer the most potential for highest hydrate concentration and exploitation. Total hydrate in formation at the sites of recognized BSR's is estimated at 17 to 190 × 109 m3 or 0.28 to 3.12 × 1013 m3 of methane gas at STP. Although it has been shown that hydrate can exist without a BSR, the results from this regional study argue that conservative estimates of the global reserve of hydrate along continental margins are necessary. © 2011.

Jerosch K.,Bedford Institute of Oceanography
Journal of Marine Systems | Year: 2013

The paper describes an approach for a quality controlled mapping of grain sizes and sediment textures for the Beaufort Shelf in the Canadian Arctic. The approach is based on grain size data collected during the Nahidik Program (2005-2009) and earlier. A replenishment of grain size data since the 1980s, as well as the consideration of correlating parameters (bathymetry, slope and sediment input) to a cokriging algorithm, amends the former way of mapping the surficial sediments of the Beaufort Shelf. The cokriging analysis showed that the simulation of a sediment input by the Mackenzie River, modeled as a cost-distance function, was the key variable in reducing the errors of the output estimate. Furthermore, the approach compares the geostatistical interpolation methods of ordinary kriging and cokriging and recommends the use of a combination of both. The predicted mean standard errors showed that in this study cokriging was the superior interpolation method for clay, silt and sand while ordinary kriging was more suitable for gravel. A new sediment texture map, based on the grain size maps, is provided according to commonly used grain size and sediment type classification systems. © 2012 Elsevier B.V.

Jessop B.M.,Bedford Institute of Oceanography
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2010

Latitudinal variability in length and age at maturity and annual growth rate for the American eel (Anguilla rostrata) along the Atlantic coast of North America was examined with respect to life history strategies and theory. Maturing (silver phase) female lengths and ages increased with increasing latitude (and distance) from the Sargasso Sea spawning site, as did male ages but not lengths. Growth rates for females (and males) declined with increasing latitude south of 44 °N latitude, approximately the entrance to the Cabot Strait, but were constant or increased within the Gulf of St. Lawrence and St. Lawrence River, depending on the analysis method. The growing season and the number of degree-days ≥ 10 °C declined with increasing latitude. Female growth rates adjusted for the number of degree-days were approximately constant south of 44 °N but increased further north, suggesting countergradient variation in growth. The temperature-size rule (increase in body size at lower temperatures) evidently applies to American eel females, but not males. No current life history model provides a satisfactory explanatory mechanism for the temperature-size rule and for anguillid life history strategies. A genetic link is proposed between increasing age (length) at elver and silver eel stages with increasing distance from the spawning area.

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