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

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