Fraser River Water Research Articles

Assessment of circulation and inter-basin transport in the Salish Sea including Johnstone Strait and Discovery Islands pathways

The Salish Sea consisting of Puget Sound and Georgia Basin in U.S and Canadian waters has been the subject of several independent data collection and modeling studies. However, these interconnected basins and their hydrodynamic interactions have not received attention as a contiguous unit. The Strait of Juan de Fuca is the primary pathway through which Pacific Ocean water enters the Salish Sea but the role played by Johnstone Strait and the complex channels northeast of Vancouver Island, connecting the Salish Sea and the Pacific Ocean, on overall Salish Sea circulation has not been characterized. In this paper we present a modeling-based assessment of the two-layer circulation and transport through the multiple interconnected sub-basins within the Salish Sea including the effect of exchange via Johnstone Strait and Discovery Islands. The Salish Sea Model previously developed using the finite volume community ocean model (FVCOM) was expanded over the continental shelf for this assessment encircling Vancouver Island, including Discovery Islands, Johnstone Strait, Broughton Archipelago and the associated waterways. A computational technique was developed to allow summation of volume fluxes across arbitrary transects through unstructured finite volume cells. Tidally averaged volume fluxes were computed at multiple transects. The results were used to validate the classic model of Circulation in Embracing Sills for Puget Sound and to provide quantitative estimates of the lateral distribution of tidally averaged transport through the system. Sensitivity tests with and without exchanges through Johnstone Strait demonstrate that it is a pathway for Georgia Basin runoff and Fraser River water to exit the Salish Sea and for Pacific Ocean inflow. However the relative impact of this exchange on circulation and flushing in Puget Sound Basin is small.

Environmental conditions and physiological state influence estuarine movements of homing sockeye salmon

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.

Sources of ground water salinity on islands using 18O, 2H, and 34S.

Stable isotopes of 18O and 2H in water, and 34S and 18O in dissolved SO4, are used to verify the interpretation of the chemical evolution and proposed sources of salinity for two islands that have undergone postglacial rebound. Results for delta18O and delta34S in dissolved SO4 on the Gulf Islands, southwest British Columbia, Canada, suggest a three-component mixing between (1) atmospheric SO4 derived largely from recharge of meteoric origin, (2) modern marine SO4 associated with either modern-day salt water intrusion or Pleistocene age sea water, and (3) terrestrial SO4. The age of the marine SO4 is uncertain based on the geochemistry and SO4 isotopes alone. Two options for mixing of saline ground waters are proposed--either between current-day marine SO4 and atmospheric SO4, or between older (Pleistocene age) marine SO4 and atmospheric SO4, delta18O and delta2H compositions are relatively consistent between both islands, with a few samples showing evidence of mixing with water that is a hybrid mixture of Fraser River water and ocean water. The isotopic composition of this hybrid water is approximately delta18O = 10 per thousand. delta18O and delta2H values for many saline ground waters plot close to the global meteoric water line, which is distinctly different from the local meteoric water line. This suggests a meteoric origin for ground waters that is different from the current isotopic composition of meteoric waters. It is proposed these waters may be late Pleistocene in age and were recharged when the island was submerged below sea level and prior to rebound at the end of the last glaciation.

Phosphorus Limitation of Heterotrophic Biofilms from the Fraser River, British Columbia, and the Effect of Pulp Mill Effluent

Experiments were conducted to determine the limiting nutrient and the effect of pulp mill effluent (PME) on heterotrophic biofilms in the Fraser River, a northern, temperate river in British Columbia, Canada. Biofilms were cultured by irrigating flow cells with Fraser River water alone (control), or river water amended with glucose; ammonium; phosphate; glucose, ammonium, and phosphate combined; or 3% PME. Phosphorus increased bacterial growth in the biofilm, which was rapidly transferred to protists, and reduced the amount of extracellular polymeric substances accumulated by biofilm bacteria. This work demonstrates phosphorus limitation of biofilm bacteria in a major river system and emphasizes the importance of nutrients in industrial discharges.

Bioconcentration of Chlorophenols by Early Life Stages of Fraser River Pink and Chinook Salmon (Oncorhynchus gorbuscha, O. tshawytscha)

Abstract Chlorophenol content of emergent pink salmon fry from five natal spawning grounds and fingerling Chinook from the Fraser River was determined. Major Chlorophenols identified were pentachlorophenol, 2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol and 2,4-dichlorophenol. Sources of these compounds appear to be lumber mills using chlorophenol based fungicides and pulp and paper mill effluents. Chlorophenol content was greatest in pink salmon fry from the Thompson River (58.4 ng/g total Chlorophenols). Fingerling Chinook from the Fraser River contained 3 7.7 ng/g total Chlorophenols. The 96-hr LC50 of Woodbrite 24, a chlorophenol based fungicide to pink salmon during the egg-to-fry stage was determined to be in the 100 to 150 ug/L range. This range is about 100 times higher than average levels reported for Fraser River water.

Natural expansion and experimental manipulation of seagrass ( Zostera spp.) abundance and the response of infaunal invertebrates

A study of an expanding seagrass bed on the south-west coast of British Columbia, Canada involved documentation and explanation of the pattern of expansion of the vegetation as well as documentation and experimental investigation of the accompanying changes in the distribution of infaunal invertebrates. Expansion followed a major environmental change, improved water clarity initiated in 1969 when a causeway blocked access to the site for silty Fraser River water. The original eelgrass ( Zostera marina) bed expanded landward over 30 m year −1, probably causing more and more water to be retained in the bed at low tide and thus improving its own habitat. More rapid expansion occurred from 1979–1983 after Z.japonica colonized at the landward edge of the eelgrass bed and in a separate intertidal area. Expansion ceased around 1983 coincident with, but probably independent of, further construction. Burrowing shrimp ( Callianassa californiensis) decreased in abundance between 1977 and 1984 in areas where the two seagrasses colonized. Short-term experiment over one summer and fall showed that removal of all shoots allowed adult shrimp and tube worms to colonize the sediment while addition of shoots of Z. japonica by transplanting caused temporary decreases in shrimp abundance. After a few weeks an established shrimp population destroyed the transplants. Among reasonable alternate hypotheses for the decline in Callianassa, the effect of sediment texture can be eliminated, but either direct negative effects of seagrass, i.e. inhibition of the burrowing of adult shrimp or of settlement of juveniles, or indirect effects, i.e. the harboring of more predators of shrimp in seagrass beds, deserve further study.

Comparative resistance of Oregon (Big Creek) and British Columbia (Capilano) juvenile chinook salmon to the myxozoan pathogen, Ceratomyxa shasta, after laboratory exposure to Fraser River water

In a laboratory experiment conducted in the fall 1983, Oregon (Big Creek) and British Columbia (Capilano) hatchery Chinook salmon were exposed to Fraser River water containing the infectious stage of the myxozoan pathogen, Ceratomyxa shasta. The juvenile fish were exposed for 10 days in 370 L of water (74 L replaced every other day for 5 days). While only 1 of 21 Big Creek fish became infected, all 20 of the Capilano fish died of C. shasta within 40 days. The Big Creek fish demonstrated high resistance to the parasite while the Capilano fish had low resistance. These results were similar to those from field exposures in previous studies.

Heterotrophic Bacterial Biomasses, Activities, and Productivities Within The Fraser River Plume

Most of the microorganisms within the silt-laden Fraser River water are bacteria, the majority of which are attached to detritus and suspended silt. However, within surface water of the Strait of Georgia bacteria constitute only about 4% of the microbial biomass; most are free-living. Within the plume, which results when the freshwater of the Fraser River mixes with the seawater of the Strait of Georgia (salinity of about 27‰ and containing mainly phytoplankton) stimulations of bacterial glucose heterotrophic activity and productivity occur throughout the year. Bacterial production is a relatively greater proportion of the total microbial, i.e. both algal and bacterial production, in the winter than in the spring or fall. Preliminary evidence indicates that the stimulation of bacterial activity and productivity may be, at least partially, due to entrainment of nitrate and phosphate-rich deep water of the Strait of Georgia into the Fraser plume.Key words: Fraser plume, bacteria, production, heterotrophic activity, Strait of Georgia

The distribution of manganese in the strait of Georgia, British Columbia

Abstract The distribution of dissolved manganese in surface waters of the Strait of Georgia is determined by the dilution of Fraser River water. Bottom waters have enhanced dissolved manganese concentrations due to reductive remobilization of manganese from the sediments. Concentrations of dissolved manganese at mid‐depths are determined by seasonal variations in the stability of the water column. Depth profiles of suspended particulate manganese indicate increasing concentrations with depth. This may result from the oxidative precipitation of manganese and/or the resuspension of bottom sediments.

Survival and heterotrophic activities of Fraser River and Strait of Georgia bacterioplankton within the Fraser River plume

Although the majority of the autochthonous heterotrophic bacterioplankton of the lower Fraser River appear to be killed when placed in Strait of Georgia marine water, their marine counterparts within Strait of Georgia surface water remain viable when treated with Fraser River water. However, within the plume water which naturally results when the freshwater of the Fraser River mixes with marine water of the Strait of Georgia, a stimulation in glucose heterotrophic activities occurs within the salinity range of approximately 3–18‰S. These increased bacterioplankton activities may be a consequence of a better nutrient environment within plume waters as compared to either parent water.

Phytoplankton Ecology of the Strait of Georgia, British Columbia

Observations of phytoplankton production, abundance, and distribution were made at 16 stations in the Strait of Georgia from 1975 to 1977. The discharge of turbid Fraser River water exerts a strong influence on phytoplankton production and distribution in surface waters by rapid light attenuation and horizontal advection. At plume boundaries and back eddies where light conditions improve, very high production occurs (> 4–5 g C∙m−2∙d−1), because of rapidly replenished nutrients supplied by the Fraser River. Advection, turbulence, zooplankton grazing, and summer nitrate depletion collectively impart a heterogeneous distribution pattern to phytoplankton in the surface waters of the Strait of Georgia. Mean annual production varies from lows of 150 g C∙m−2 in Fraser River plume to highs of over 500 g C∙m−2 in sheltered boundary waters of inlets. Recent increases in ammonia and nitrate from land drainage and domestic sewage, mainly through the Fraser River, are related to increases in phytoplankton standing stocks in the Strait. Key words: phytoplankton, primary production, eutrophication, coastal marine, phytoplankton distribution and succession, chlorophyll a, pelagic

Offshore Characteristics in the Deep Waters of the Strait of Georgia as Indicated by Bathypelagic Fish

An attempt is made from oceanographical observations to explain the occurrence of certain bathypelagic species of fish which have been captured in the bottom waters of the southern Strait of Georgia. It is noted that there is a considerable seaward surface Sow of water from the Fraser River. The water from intermediate depths over the continental shelf forms the inflowing deep water of Juan de Fuca Strait mixing with the Fraser River water in the turbulent channels of the San Juan Archipelago. This mixture forms the deep inflowing water of southern Strait of Georgia and the outflowing surface water of the Juan de Fuca Strait as shown by salinity distribution and current measurements. The net inward movement of deep water is suggested as an agent of transport or a directive factor for the occurrence of these fish in this region. Physical and chemical conditions of the deep water in the Strait of Georgia are shown to be only slightly different from those found in the intermediate offshore water. It is probable that a combination of factors provides conditions suitable for survival of these species in the deep water of the southern Strait of Georgia.