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Physical and Water Quality Data
Researchers from the Pacific Coastal Ecology Branch, Environmental Protection Agency in Newport presented results of multi-year cruises as will other time-series data
Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary
Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water
environments, and is often attributed to anthropogenic nutrient enrichment from
terrestrial-fluvial pathways. However, recent events in the U.S. Pacific
Northwest have highlighted that wind-forced upwelling can cause naturally
occurring low DO water to move onto the continental shelf, leading to
mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific
Northwest are strongly linked to ocean forcings, and here we report observations
on the spatial and temporal patterns of oxygen concentration in the Columbia
River estuary. Hydrographic measurements were made from transect (spatial
survey) or anchor station (temporal survey) deployments over a variety of wind
stresses and tidal states during the upwelling seasons of 2006 through 2008.
During this period, biologically stressful levels of dissolved oxygen were
observed to enter the Columbia River estuary from oceanic sources, with minimum
values close to the hypoxic threshold of 2.0 mg L−1. Riverine
water was consistently normoxic. Upwelling wind stress controlled the timing and
magnitude of low DO events, while tidal-modulated estuarine circulation patterns
influenced the spatial extent and duration of exposure to low DO water. Strong
upwelling during neap tides produced the largest impact on the estuary. The
observed oxygen concentrations likely had deleterious behavioral and
physiological consequences for migrating juvenile salmon and benthic crabs.
Based on a wind-forced supply mechanism, low DO events are probably common to
the Columbia River and other regional estuaries and if conditions on the shelf
deteriorate further, as observations and models predict, Pacific Northwest
estuarine habitats could experience a decrease in environmental quality
Residue profile of PCB, PCN and CBz in fish, algae, MOSS and sediment from the polluted river Krupa (Slovenia)
Seasonal discharge and chemical flux variations of rivers flowing into the Bayhead canal of Durban Harbour, South Africa
Holocene to Middle Last Glaciation vegetation history at Tullabardine Dam, western Tasmania
Isotopic shifts with size, culture habitat, and enrichment between the diet and tissues of the Japanese scallop Mizuhopecten yessoensis (Jay, 1857)
Use of stable isotope signatures to trace diet patterns in cultured marine bivalves, particularly when changing culture habitat, requires knowledge of the isotopic shift and enrichment between diet and consumer's tissues. The aim of this study was to determine the patterns of isotope change and the variability of enrichment values (Δδ13C and Δδ15N) in different tissues (muscle, gonad, digestive gland) of the Japanese scallop (Mizuhopecten yessoensis). It was hypothesized that the isotopic signatures of a consumer's tissues changed during settlement, and that the changes were related to variations in the isotopic signatures of food sources and gut contents. Particular attention was paid to the isotope enrichment between the diet and a consumer's tissues using isotope analysis of gut content. Muscle δ15N values decreased significantly 3-5 months post-settlement in a nearshore seabed, concomitant with the ingestion of lower δ15N food. For juvenile scallops, sinking particles (SP) were considered a more important dietary source than suspended particulate organic matter (SPOM), based on the correspondence between SP and gut contents δ13C. Enrichment values (Δδ13C and Δδ15N) varied with tissue and season. Δδ15N was 2.4‰ in muscle, 1.2‰ in gonad, and 0.7‰ in the digestive gland. Δδ13C was 3.2‰ in muscle, 2.3‰ in gonad, and -0.5‰ in the digestive gland. Δδ15N was the lowest in summer (0.3‰), and Δδ13C was the highest in autumn (2.8‰). Δδ15N values were significantly influenced by age, but not Δδ13C. Patterns of isotope ratios and enrichment values may be related to physiological attributes and differences in diet. This is the first study to demonstrate isotopic shift and enrichment encountered in different tissues of a cultured scallop when changing culture habitat
Changes In Spruce Composition Following Burial In Lake-sediments For 10,000 Yr
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62582/1/287534a0.pd