Elliott Bay Research Articles

Temporal Variability of Microparticles Under the Seattle Aquarium, Washington State: Documenting the Global Covid-19 Pandemic.

Anthropogenic debris including microparticles (<5 mm) are ubiquitous in marine environments. The Salish Sea experiences seasonal fluctuations in precipitation, river discharge, sewage overflow events, and tourism—all variables previously thought to have an impact on microparticle transport and concentrations. Our goals are two‐fold: 1) describe long‐term microparticle contamination data including concentration, type, and size; and 2) determine if seasonal microparticle concentrations are dependent on environmental or tourism variables in Elliott Bay, Salish Sea. We sampled 100 L of seawater at a depth of approximately 9 m at the Seattle Aquarium, Seattle, Washington State, United States, approximately every two weeks from 2019 through 2020 and used an oil extraction protocol to separate microparticles. We found that microparticle concentrations ranged from 0 to 0.64 particles L−1 and fibers were the most common type observed. Microparticle concentrations exhibited a breakpoint on 10 April 2020, where estimated slope and associated microparticle concentration significantly declined. Further, when considering both environmental as well as tourism variables, temporal microparticle concentration was best described by a mixed‐effects model, with tourism as the fixed effect and the person counting microparticles as the random effect. Although monitoring efforts presented set out to identify effects of seasonality and interannual differences in microparticle concentrations, it instead captured an effect of decreased tourism due to the global Covid‐19 pandemic. Long‐term monitoring is critical to establish temporal microparticle concentrations and to help researchers understand if there are certain events, both seasonal and sporadic (e.g., rain events, tourism, or global pandemics), when the marine environment is more at risk from anthropogenic pollution. Environ Toxicol Chem 2022;41:917–930. © 2021 Seattle Aquarium. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Seawall as salmon habitat: Eco-engineering improves the distribution and foraging of juvenile Pacific salmon

Urban nearshore ecosystems are built environments that differ structurally and functionally from the natural ecosystems they replace. Eco-engineering offers the ability to enhance these ecosystems by reducing the impacts of shoreline modification. Recent studies have linked shoreline armoring and pier shade—common features of modified shorelines—to lower foraging rates, altered distribution patterns, and increased predation risk for juvenile salmon. The 2017 replacement of the Elliott Bay seawall in Seattle, WA, USA incorporated novel eco-engineering design elements, including glass light penetrating surfaces (LPS) in overwater structures, an elevated seafloor, and textured substrates in the seawall face to enhance nearshore habitat for juvenile Pacific salmon (Oncorhynchus spp.) migrating from natal streams to the ocean. To examine the effectiveness of seawall eco-engineering, we used snorkel surveys to assess changes in juvenile salmon spatial distribution and foraging patterns during peak outmigration (March–August), and measured ambient light penetration before and after seawall replacement. Overall, we found that juvenile salmon were distributed more evenly across a spatial mosaic of habitats following eco-engineering. LPS enhanced ambient light penetration in nearshore under-pier habitats, and juvenile salmon use of these habitats increased concurrently. Salmon densities under piers tended to be greatest at low tides, indicating that light availability may mediate selective habitat use. Feeding rates at sites immediately adjacent to the seawall increased both between and under piers following habitat enhancement. Our findings suggest that the elevated light levels facilitated by LPS, in concert with physical enhancements that provided more complex shallow water habitat, temper the negative effects of pier shade and shoreline armoring on juvenile salmon.

Ground Improvement Design and Construction for Seattle's Elliott Bay Seawall Replacement and Retrofit

The Elliott Bay Seawall in Seattle, Washington, was constructed in the early 1900s over soft/loose non-engineered and liquefaction susceptible fill, estuary, and beach deposits. The fill includes wood from historic waterfront sawmills and debris from the 1889 Great Seattle Fire. After the 2001 Nisqually earthquake, an evaluation of the seawall condition and seismic vulnerability determined that it had undergone significant deterioration and was susceptible to collapse for a 100-year earthquake. This evaluation led to design and replacement/retrofit of 1,130 meters (3,700 feet) of seawall. The new seawall includes an improved soil mass constructed of a cellular arrangement of jet-grout columns that supports a seawall superstructure and provides all seismic lateral restraint. The improved soil mass seismic performance criteria are based on allowable seawall displacement for three earthquake ground motion levels. Final improved soil mass design utilized non-linear dynamic soil-structure interaction analyses. To meet performance criteria, improved soil mass widths range between 7.9 and 18.3 meters (26 and 60 feet), ground improvement area replacement ranges between 50 and 64 percent, and jet-grout soil-cement unconfined compressive strength ranges between 0.86 and 2.76 MPa (125 and 400 psi), depending on the soil type. Improved soil mass construction issues included equipment selection, limited space, spoils handling, wood debris, and obstructions (e.g., buried utilities, piles, and temporary shoring). Lessons learned included: (1) jet grouting was the best construction method given the utilities and thousands of piles beneath the site, (2) early obstructions identification and contingency plans are critical to maintain production, and (3) an understanding of space requirements for all construction activities is required for safe and productive working conditions.

Decrease in Sightings of Sixgill Sharks, Hexanchus griseus, in Elliott Bay, Seattle, WA, United States, a Comparison Between 2003–2005 and 2008–2015

The Bluntnose Sixgill Shark, Hexanchus griseus, is a large predatory shark, has a worldwide distribution and is listed as near-threatened by the International Union of Conservation of Nature (IUCN). The Seattle Aquarium collected observations of free-swimming Sixgill Sharks in Elliott Bay, Washington, under the aquarium’s pier in 20 m of water from 2003 to 2005 and again from 2008 to 2015 using the same methodology. Compared to total Sixgill sightings between 2003-2005 (273) fewer total Sixgills were sighted at the aquarium’s research station between 2008-2015 (33). The reason for the observed decline in sightings in unknown but based on data from other studies on Sixgills in Puget Sound during the same timeperiod the authors hypothesize the decrease may be due to natural variability of juvenile Sixgill recruitment to Elliott Bay.

Blue Seattle: Immanent ethics and contemporary urbanisation

This paper asserts that critical investigations into the urbanisation process should consider the actually existing ethics of the process itself, without defaulting to transcendent normative principles. Grounded in an ontology of immanence, as presented in Deleuze and Guattari's (9) political philosophy, I argue that attention must be paid to the production and transformation of normativity. Using the redevelopment of the South Lake Union (SLU) neighbourhood of Seattle – (in)famously home to Amazon, but largely envisioned and developed by Paul Allen's investment and philanthropic organisation, Vulcan – as an analytical starting point, this paper sketches out a profile of the “blue” dimension of the genesis of Seattle's environmental ethic, from early efforts to reshape the region's hydrology and address water pollution in Lake Washington, through efforts by governmental bodies and Vulcan to protect water quality and salmon habitat, and on to a large‐scale infrastructure project – the Elliott Bay Seawall replacement – that includes features to enhance biodiversity and ecological functioning in the nearshore environment. In tracking these movements, I identify the emergence of an explicitly post‐anthropocentric ethic from what initially appears as an aesthetic concern, while also highlighting the ongoing complexification of an earlier engineering ethic that dates back to the earliest attempts by settlers to manage the natural environment.

Safer in Seattle

Constructed in the early 1900s, the Elliott Bay Seawall, in Seattle, protects the city’s downtown waterfront from the erosive forces of Puget Sound and Elliott Bay. Because of its deteriorating condition and seismic vulnerability, it was replaced with a new seawall, one that makes extensive use of modular precast concrete components that sped construction, enhanced durability, reduced project costs, and minimized impacts to adjacent properties.

Good News and Bad News in Two Highly Industrialized Puget Sound, Washington (u.s.a.) Embayments

AbstractIn this study, an offshoot of studies undertaken by the Washington State Department of Ecology (WDOE), the density and diversity of foraminiferal assemblages in Commencement and Elliott bays, two heavily industrialized embayments in Puget Sound, Washington (U.S.A) were compared and correlated with concentrations of metal pollutants and total polycyclic aromatic hydrocarbons (PAH). Samples used in this study were collected by the WDOE between 1998 and 2014, allowing comparison over a temporal range encompassing the beginnings of environmental remediation in both bays. The composition of the foraminiferal assemblages is typical of polluted estuaries globally, with the major taxa being Elphidiella hannai, Cribroelphidium excavatum, Bucella frigida and Eggerella advena. Foraminiferal density and diversity showed negative correlations with pollutants, however, these correlations were significant for only a few pollutants, and trends could not be attributed to any single one. Both embayments showed increasing diversity over time, and both had high proportions of calcareous tests that displayed signs of dissolution, indicating corrosive conditions in the water. In Elliott Bay the percentage of partially dissolved tests increased over time, suggesting remediation efforts have not been successful in all areas.

Habitat restoration incentives for major infrastructure projects

ABSTRACTIncentives for early consideration of habitat restoration measures for major infrastructure projects include public support, streamlined regulatory review, cost savings, and opportunities for innovation. Three case study projects in Washington State are used to demonstrate the benefits of these incentives: the Seattle Department of Transportation Elliott Bay Seawall Project in Seattle; the Washington State Department of Transportation State Route 520 Bridge Replacement and High-occupancy Vehicle Program between Seattle and Bellevue; and the Washington State Department of Ecology/U.S. Bureau of Reclamation Yakima River Basin Integrated Water Resource Management Plan in the Yakima River Basin. In all case studies, project proponents considered habitat restoration early in the design phase, and in some cases, incorporated habitat restoration into the design of the project, allowing them to develop innovative design approaches and partnerships to accommodate multiple stakeholder interests and provide ...

Feeding Behavior of Subadult Sixgill Sharks (Hexanchus griseus) at a Bait Station

This is the first in-situ study of feeding behaviors exhibited by bluntnose sixgill sharks. Bait was placed beneath the Seattle Aquarium pier situated on the waterfront in Elliott Bay, Puget Sound, Washington at 20m of water depth. Cameras and lights were placed around the bait box to record sixgill shark presence and behavior while feeding. Analysis of feeding behavior revealed that sixgills utilize a bite comparable to many other elasmobranchs and aquatic vertebrates, have the ability to protrude their upper jaw, change their feeding behavior based on the situation, and employ sawing and lateral tearing during manipulation. The versatility of their feeding mechanism and the ability of sixgills to change their capture and food manipulation behaviors may have contributed to the species’ worldwide distribution and evolutionary success.

Environmental Reviews and Case Studies: An Interdisciplinary Approach to Environmental Planning and Permitting: City of Seattle Elliott Bay Seawall Project Case Study

Creating and implementing effective tools for navigating the regulatory process is becoming increasingly important to the success of simple to complex projects, particularly those in urban settings. To guide a project through the planning and permitting processes, a skilled and coordinated team equipped with a practical and easily implementable toolkit is required. Tools must be integrated into the design development phase of a project and throughout the permitting phase to adequately meet complex regulatory requirements and begin the project's construction in a timely and cost-effective manner. This article discusses the importance of defining a project, effective project communication, developing an Environmental Approvals Approach (EAA), and proper project scheduling to improve the environmental planning and permitting processes. The City of Seattle's Elliott Bay Seawall Project is presented as a case study of these qualities.

Effects of shoreline engineering on shallow subtidal fish and crab communities in an urban estuary: A comparison of armored shorelines and nourished beaches

Shoreline armoring is common worldwide, yet its ecological effects have only recently been investigated. In this study, we surveyed shallow subtidal fish and crab communities at three sites with shorelines modified by seawall and riprap armoring and at three beaches with no armoring, all along the urbanized Elliott Bay shoreline of Seattle, WA (USA). Similar to many urban areas there is little natural shoreline remaining in Elliott Bay and beach sites were nourished with sediment that was similar to the historical structure of ambient nearshore habitats. We visually surveyed fish and crabs along scuba dive transects at these sites for eighteen months to quantify the composition of their communities and the association of fish and crabs with substrate types. The community composition and substrate type associations were similar among seawall sites and distinct from those at nourished beaches. Some species were predominantly associated with one substrate type (e.g., sand, riprap) and their densities at each site corresponded to the availability of this substrate type. Our results suggest that hard structures in engineered subtidal habitats may benefit some species that select for these introduced structures despite these structures not occurring historically. It is also clear that the creation of nourished beaches within armored shorelines can maintain different fish and crab communities than those associated with armoring, even in highly urbanized systems. Our study contributes to a growing literature that suggests that shoreline armoring and other types of habitat modifications affect the ecology of nearshore waters and the composition of nearshore communities.

Observations on Abundance of Bluntnose Sixgill Sharks, Hexanchus griseus, in an Urban Waterway in Puget Sound, 2003-2005

The bluntnose sixgill shark, Hexanchus griseus, is a widely distributed but poorly understood large, apex predator. Anecdotal reports of diver-shark encounters in the late 1990’s and early 2000’s in the Pacific Northwest stimulated interest in the normally deep-dwelling shark and its presence in the shallow waters of Puget Sound. Analysis of underwater video documenting sharks at the Seattle Aquarium’s sixgill research site in Elliott Bay and mark-resight techniques were used to answer research questions about abundance and seasonality. Seasonal changes in relative abundance in Puget Sound from 2003–2005 are reported here. At the Seattle Aquarium study site, 45 sixgills were tagged with modified Floy visual marker tags, along with an estimated 197 observations of untagged sharks plus 31 returning tagged sharks, for a total of 273 sixgill observations recorded. A mark-resight statistical model based on analysis of underwater video estimated a range of abundance from a high of 98 sharks seen in July of 2004 to a low of 32 sharks seen in March of 2004. Both analyses found sixgills significantly more abundant in the summer months at the Seattle Aquarium’s research station.

Elliott Bay Overlook

Elliott Bay Overlook

Catch Rates and Biological Characteristics of Bluntnose Sixgill Sharks in Puget Sound

AbstractThe bluntnose sixgill shark Hexanchus griseus is a wide‐ranging marine predator and the largest predatory shark in Puget Sound. Biological characteristics of the Puget Sound bluntnose sixgill shark population remain largely undocumented, despite a recent escalation in recreational angling for the species. Standardized longline sampling, supplemented with other opportunistic collections, was used to collect size, sex ratio, and relative catch rate data at three locations during 2006–2008. Fishing trials were also used to examine the effect of soak time, fishing depth, and time of day on catch rates. Captured bluntnose sixgill sharks were exclusively subadults (175–315 cm total length) found in approximately equal sex ratios in all seasons. Catch rates were highest in Elliott Bay, the urbanized port of Seattle, Washington, and were not affected by sampling season. Catch information derived from hook timers implies that the sharks locate and encounter baited hooks relatively rapidly (&lt;2 h); diel fishing trials suggest some trend toward lower catch rates at shallower sites during the day. Data collected in this study provide some basic context for informing management decisions associated with a large marine predator in the Puget Sound–Georgia Basin ecosystem and improve our basic understanding of bluntnose sixgill shark biology in the region.

Diel activity patterns of sixgill sharks, Hexanchus griseus: the ups and downs of an apex predator

The activity patterns for most animals are determined through a trade-off among competing processes, such as foraging behaviour, predator or competitor avoidance, and maintaining bioenergetic efficiency. We used active and passive acoustic telemetry to examine what processes may contribute to diel and seasonal patterns of vertical movement in 27 sixgill sharks in Puget Sound, WA, U.S.A., from December 2005 to December 2007. We found clear and consistent patterns of diel activity; sixgill sharks were typically shallower and more active at night than during the day. In Elliott Bay, WA, sixgill sharks made direct vertical movements at sunrise and sunset, while vertical movements were more variable in deeper, main channel waters. The greatest rates of ascent and descent in sixgill sharks occurred most often during night-time ebb tides. Seasonally, sixgill sharks occupied deeper habitats during the autumn and winter than during spring and were most active in the autumn. We also found synchronous vertical movements in three of four shark pairs tracked simultaneously, evidence that these sharks were responding to similar stimuli. Clear and consistent patterns of diel activity throughout the year across size and sex of sharks and across multiple spatial scales is most consistent with the hypothesis that foraging behaviour is responsible for the patterns of diel vertical movement of sixgill sharks in Puget Sound.

Xenoestrogen exposure and effects in English sole ( Parophrys vetulus) from Puget Sound, WA

Vitellogenin, a yolk protein produced in the liver of oviparous animals in response to estrogens, normally occurs only in sexually mature females with developing eggs. However, males can synthesize vitellogenin when exposed to environmental estrogens, making the abnormal production of vitellogenin in male animals a useful biomarker for xenoestrogen exposure. In 1997–2001, as part of the Washington State's Puget Sound Assessment and Monitoring Program, we surveyed English sole from a number of sites for evidence of xenoestrogen exposure, using vitellogenin production in males as an indicator. Significant levels of vitellogenin were found in male fish from several urban sites, with especially high numbers of fish affected in Elliott Bay, along the Seattle Waterfront. Intersex fish were rare, comprising only two fish out of more than 2900 examined. Other ovarian and testicular lesions, including oocyte atresia, were also observed, but their prevalence did not appear to be related to xenoestrogen exposure. However, at the Elliott Bay sites where abnormal vitellogenin production was observed in male sole, the timing of spawning in both male and female English sole appeared altered. Sources of xenoestrogens and types of xenoestrogens present in Elliott Bay are poorly documented, but the compounds are likely associated with industrial discharges, surface runoff, and combined sewer outfalls.

Significance of Devonian–Carboniferous igneous activity in Tasmania as derived from U–Pb SHRIMP dating of zircon

A series of new Sensitive High-Resolution Ion MicroProbe (SHRIMP) U – Pb ages is presented for Palaeozoic (mainly Devonian and Carboniferous) granites from Tasmania. In virtually all instances the new ages are significantly older than previously determined Rb – Sr and K – Ar ages, even though the level of emplacement had been thought to be too shallow to allow loss of radiogenic daughter products. In two extreme cases, granite bodies at South West Cape and Elliott Bay that had previously yielded Carboniferous Rb – Sr and Early Devonian K – Ar ages, respectively, are now both shown to be Late Cambrian. In northeast Tasmania, granitic activity in the Blue Tier Batholith lasted for about 22 million years, with I-type magmas being followed by S-types only toward the end of that time. The exclusively I-type granites of the Scottsdale Batholith formed about 10 million years after the initiation of igneous activity in the Blue Tier Batholith, and were emplaced over a comparatively short time interval (4 – 5 million years). The new data confirm a previously held view, based on Rb – Sr analysis, that the economically important Lottah Granite crystallised roughly 9 million years later than the nearby Poimena Granite and, therefore, could not have been derived by magmatic fractionation of the latter. A regional deformation equated with the Tabberabberan Orogeny has been dated at about 390 Ma in northeastern Tasmania, based on the presence or absence of a northwest-trending foliation in the different granite bodies. The oldest granites occur in the northeast of Tasmania, with an irregular progression of ages to the west coast. A trend of this type could have arisen in an arc-free or arc-related environment. If the latter applies, either flat subduction or processes associated with the amalgamation of eastern and western basement terranes might be the controlling mechanism. Eastern Tasmania experienced a trend from mafic I-type to progressively more felsic, largely S-type igneous activity, but the trend for western Tasmania is not as obvious. The trend for eastern Tasmania is an exception to the general rule for the Lachlan Orogen, possibly signifying that the mid-crust was relatively cool when the first I-type granites were generated. Crustal thickening during the Tabberabberan Orogeny may have been a prerequisite for the generation of later, more felsic, S- and I-types.

Assessment of seasonal variability of cytochemical responses to contaminant exposure in the blue mussel Mytilus edulis (complex).

A selected suite of cytochemical parameters in Mytilus edulis are altered in response to field and laboratory exposure to chemical contaminants. These biomarkers include lysosomal stability, nicotinamide adenine dinucleotide phosphate (NADPH)-ferrihemoprotein reductase activity, liposfuscin deposition, and accumulation of lysosomal and cytoplasmic unsaturated neutral lipid. Normal variations in physiological processes (influenced by exogenous seasonal changes in temperature, salinity, food availability, etc.) may alter the sensitivity of these biomarkers to contaminant exposure. To address this issue, M. edulis (complex) were sampled monthly from a reference nonurban site (Coupeville, Penn Cove) and a polluted urban site (Seacrest, Elliott Bay) in Puget Sound, WA, for a period of 15 months. Physiological measurements including total length, total weight, somatic and mantle weights (an indication of gonadal development and reproductive status), condition index, and the presence or absence of hemic neoplasia (HN, or leukemia) were recorded. Significant differences in lysosomal stability, lysosomal and cytoplasmic unsaturated neutral lipids, lipofuscin deposition, and NADPH-ferrihemoprotein reductase activity in cells of the digestive gland or digestive tubules were generally found in mussels taken throughout the year from Seacrest compared to mussels sampled from Coupeville, consistent with exposure to chemical contaminants. No seasonally influenced suppression of the entire suite of parameters as measures of contaminant exposure was evident. Therefore these biomarkers can be used to evaluate contaminant exposure in mussels throughout the entire year.

A field validation of two sediment‐amphipod toxicity tests

AbstractA field validation study of two sediment‐amphipod toxicity tests was conducted using sediment samples collected subtidally in the vicinity of a polycyclic aromatic hydrocarbon (PAH)‐contaminated Superfund site in Elliott Bay (WA, USA). Sediment samples were collected at 30 stations with a 0.1 m2 grab from which subsamples were taken for sediment toxicity testing and geochemical and macrofaunal analyses. Standard 10‐d sediment‐amphipod toxicity tests were conducted with Rhepoxynius abronius and Leptocheirus plumulosus. Sediments were analyzed for 33 PAHs, pentachlorophenol, polychlorinated biphenyls, acid‐volatile sulfide, simultaneously extracted metals (Cd, Cu, Zn, Pb, Ni), total organic carbon, and grain size. Sediment temperature, oxygen‐reduction potential, water depth, and interstitial water salinity were also measured. Polycyclic aromatic hydrocarbons, quantified as total PAH toxic units (TUPAH), were confirmed to be an important common causal agent of the changes in the two toxicity test (% survival R. abronius, % survival L. plumulosus) and five macrofaunal community (number of species, S; numerical abundance, A; total biomass, B; Swartz's dominance index, SDI; Brillouin's index, H) endpoints. Two other macrofaunal community metrics (the complement of Simpson's index, 1 — SI, and McIntosh's index, MI) were less sensitive to TUPAH than the two toxicity test endpoints. The sensitivities of R. abronius and L. plumulosus to TUPAH were statistically indistinguishable. Field validations were conducted by testing the association between or among each toxicity test endpoint, each of seven macrofaunal community metrics (S, A, B, SDI, H, 1 — SI, MI), and TUPAH by (1) Spearman's coefficient of rank correlation, (2) Kendall's coefficient of concordance, (3) G tests of independence, and (4) regression analysis. Some field validations based on multivariable tests of association (e.g., points 2 and 3) among toxicity test, field, and stressor endpoints produced false positive results. Both toxicity test endpoints were validated as indicators of changes in S, A, SDI, and H by all the methods tested. The resolution power of the relationships between the laboratory toxicity test and macrofaunal field endpoints was low (⩽ three classes) but sufficient to discriminate ecologically important effects. We conclude that standard sediment‐amphipod toxicity tests are ecologically relevant and that, under the proper conditions, their results can be used for lab‐to‐field extrapolation.

A field validation of two sediment-amphipod toxicity tests.

A field validation study of two sediment-amphipod toxicity tests was conducted using sediment samples collected subtidally in the vicinity of a polycyclic aromatic hydrocarbon (PAH)-contaminated Superfund site in Elliott Bay (WA, USA). Sediment samples were collected at 30 stations with a 0.1 m2 grab from which subsamples were taken for sediment toxicity testing and geochemical and macrofaunal analyses. Standard 10-d sediment-amphipod toxicity tests were conducted with Rhepoxynius abronius and Leptocheiros plumulosus. Sediments were analyzed for 33 PAHs, pentachlorophenol, polychlorinated biphenyls, acid-volatile sulfide, simultaneously extracted metals (Cd, Cu, Zn, Pb, Ni), total organic carbon, and grain size. Sediment temperature, oxygen-reduction potential, water depth, and interstitial water salinity were also measured. Polycyclic aromatic hydrocarbons, quantified as total PAH toxic units (TU(PAH)), were confirmed to be an important common causal agent of the changes in the two toxicity test (% survival R. abronius, % survival L. plumulosus) and five macrofaunal community (number of species, S; numerical abundance, A: total biomass, B: Swartz's dominance index, SDI; Brillouin's index, H) endpoints. Two other macrofaunal community metrics (the complement of Simpson's index, 1 - SI, and McIntosh's index, MI) were less sensitive to TU(PAH) than the two toxicity test endpoints. The sensitivities of R. abronius and L. plumulosus to TU(PAH) were statistically indistinguishable. Field validations were conducted by testing the association between or among each toxicity test endpoint, each of seven macrofaunal community metrics (S, A, B, SDI, H, 1 - SI, MI), and TU(PAH) by (1) Spearman's coefficient of rank correlation, (2) Kendall's coefficient of concordance, (3) G tests of independence, and (4) regression analysis. Some field validations based on multivariable tests of association (e.g., points 2 and 3) among toxicity test, field, and stressor endpoints produced false positive results. Both toxicity test endpoints were validated as indicators of changes in S, A, SDI, and H by all the methods tested. The resolution power of the relationships between the laboratory toxicity test and macrofaunal field endpoints was low (< or = three classes) but sufficient to discriminate ecologically important effects. We conclude that standard sediment-amphipod toxicity tests are ecologically relevant and that, under the proper conditions, their results can be used for lab-to-field extrapolation.