Adding Texture and Relief to Seattle’s New Seawall, an Application of Ecological Engineering

The aftermath of the 2001 Nisqually earthquake revealed that Seattle’s seawall was decaying and in need of replacement. The resulting seawall replacement project presented an opportunity to replace vertical featureless walls with more complex and productive habitat. Several years before the new seawall was designed, the City of Seattle invited University of Washington biologists to participate in developing concepts for improved seawall habitat. This resulted in collaborations with several City of Seattle departments, during which we designed, deployed, and evaluated large habitat panels that tested several types of slopes and textures. Four years of monitoring algae, sessile invertebrates, and epibenthic organisms demonstrated that important biological “ecosystem engineers” benefited from adding texture and relief to seawalls. For example, compared to simple flat treatments and the existing seawall, recruitment of mussels was increased on panels with cobble texture, and rockweed was more abundant on high relief “finned” and “stepped” panels. Species richness of biota was also higher on surfaces with higher habitat complexity. This project represents a successful test of ecological engineering concepts, and the findings are being incorporated into the seawall that is currently being built. The City’s 10-year monitoring and adaptive management plan will allow for continued evaluation of these types of habitat enhancements on a larger scale. Invited comment: Mark Mazzola, Environmental Manager for the Seattle Department of Transportatio

Shoreline armoring disrupts marine-terrestrial connectivity in the Salish Sea, with consequences for invertebrates, fish, and birds

Within the marine-terrestrial ecotone, upper intertidal “wrack zones” accumulate organic debris from algae, seagrass, and terrestrial plant sources and provide food and shelter for many organisms. We conducted detailed surveys of wrack and log accumulations and supralittoral invertebrates in spring and fall over 3 years at 29 armored-unarmored beach pairs in Puget Sound, WA, USA. Additionally, behavioral observations of juvenile salmon (Oncorhynchus spp.) and birds were conducted at 6 pairs. Armored beaches had substantially less wrack overall, a lower proportion of terrestrial plant material in the wrack, and far fewer logs. Armored beaches had significantly fewer invertebrates and differed from unarmored beaches in their taxonomic composition. Unarmored invertebrate assemblages were dominated by talitrid amphipods and insects, and were correlated with the amount of beach wrack and logs, the proportion of terrestrial material in wrack, and the maximum elevation of the beach. Shoreline armoring influenced juvenile salmon distribution, with fewer overall observations and fish in deeper water at armored beaches, but their feeding rates were relatively high at all sites. Terrestrial birds were commonly observed foraging among beach wrack and logs at unarmored beaches, but were largely absent from armored beaches. This study demonstrates that shoreline armoring disrupts marine-terrestrial connectivity, affecting the amount and type of organic material delivered to the nearshore ecotone in the form of wrack and logs, the abundance and taxonomic composition of supralittoral invertebrates, and the distribution and behavior of secondary consumers (juvenile salmon and birds)

Shoreline armoring removal: assessment of restoration effectiveness in the Salish Sea

Shoreline armoring removal is becoming a common restoration technique in the nearshore of the Salish Sea, yet we lack a comprehensive understanding of the ecological benefits obtained, and how such an understanding could be used to inform management recommendations and educate diverse audiences. To address this knowledge gap, we studied effects of shoreline armor removal at 10 sites, expanding the spatial framework of what was previously known by collaborating across academic (University of Washington), agency (Washington Department of Fish and Wildlife), and citizen science groups. Each site had three beach types of: (1) restored beaches with armoring removed 1-11 years ago, with a mean of four years, (2) armored beaches altered by bulkheads or riprap, and (3) un-armored reference beaches with more natural conditions. We sampled eight metrics of physical and biological conditions, focusing on supratidal and upper intertidal elevations most affected by armoring and targeted by restoration actions: beach wrack, wrack invertebrates, sediments, terrestrial insects, riparian vegetation and logs, beach profiles, forage fish habitat, and stable isotopes of beach-hopper amphipods to reveal ratios of marine and terrestrial food sources. These metrics spanned the functions of beach stability, ecological diversity, and food web support for juvenile salmon and birds. Results indicated that some beach metrics restore quickly, such as wrack accumulation, while others take longer, such as log accumulation. Sediment sizes at restored beaches approximated those of reference beaches, and were appropriate for forage fish spawning. In general, terrestrial-associated metrics were greater at reference beaches, although there was evidence that insect diversity and logs with plant growth increased when beaches were restored greater than four years. This implies that restored beach functions increase through time, providing improved support for forage fish, salmon, and birds

Variation in juvenile Chinook salmon diet composition and foraging success between two estuaries with contrasting land-use histories

The transition of juveniles from fresh water to estuarine and marine environments is a critical period in the life cycle of Pacific salmon, during which survival can be strongly size-selective. Because the amount and quality of food consumed are major determinants of juvenile salmon growth, successful acquisition of energy rich prey during estuarine residence is critical for survival. Humans have likely impacted the feeding relationships of juvenile salmon in estuaries by destroying estuarine wetlands and by altering the abundance of salmon in estuaries. While the estuarine foraging habits of juvenile salmon have been extensively examined, few studies have conducted quantitative comparisons between estuaries that have experienced different levels of human modification. However, comparisons between whole estuaries with different degrees of wetland loss and degradation may be a useful scale of analysis for the diet composition and consumption rates of mobile consumers such as juvenile salmon. To improve our understanding of the effects of wetland loss and conspecific density on juvenile Chinook salmon consumption rate and diet composition in estuaries, we assembled Chinook salmon density and diet data from two Salish Sea estuaries with dramatically different levels of wetland loss and modification. We compared juvenile Chinook salmon diet composition, diet energy density, and instantaneous ration (a proxy for consumption rate) between the two estuaries. We also evaluated the effect of conspecific density on instantaneous ration. We found significant differences in diet composition between juvenile Chinook salmon in the two estuaries, but little difference in instantaneous ration or diet energy density. However, in the highly modified estuary, conspecific density had a significant, negative effect on instantaneous ration, while in the more natural estuary there was little effect on instantaneous ration. These findings suggest that wetland loss may interact with salmon density to constrain the consumption rates of juvenile salmon in estuaries, with resulting consequences for growth and survival

Genetic Variation in VEGF Does Not Contribute Significantly to the Risk of Congenital Cardiovascular Malformation

Several previous studies have investigated the role of common promoter variants in the vascular endothelial growth factor (VEGF) gene in causing congenital cardiovascular malformation (CVM). However, results have been discrepant between studies and no study to date has comprehensively characterised variation throughout the gene. We genotyped 771 CVM cases, of whom 595 had the outflow tract malformation Tetralogy of Fallot (TOF), and carried out TDT and case-control analyses using haplotype-tagging SNPs in VEGF. We carried out a meta-analysis of previous case-control or family-based studies that had typed VEGF promoter SNPs, which included an additional 570 CVM cases. To identify rare variants potentially causative of CVM, we carried out mutation screening in all VEGF exons and splice sites in 93 TOF cases. There was no significant effect of any VEGF haplotype-tagging SNP on the risk of CVM in our analyses of 771 probands. When the results of this and all previous studies were combined, there was no significant effect of the VEGF promoter SNPs rs699947 (OR 1.05 [95% CI 0.95–1.17]); rs1570360 (OR 1.17 [95% CI 0.99–1.26]); and rs2010963 (OR 1.04 [95% CI 0.93–1.16]) on the risk of CVM in 1341 cases. Mutation screening of 93 TOF cases revealed no VEGF coding sequence variants and no changes at splice consensus sequences. Genetic variation in VEGF appears to play a small role, if any, in outflow tract CVM susceptibility

Genetic Analysis Workshop 15: gene expression analysis and approaches to detecting multiple functional loci

National Institutes of Health (AR44422, N01-AR-7-2232, 5R01-HL049609-14, IR01-AG021917-01A1); Genome Canada and Associations AFP; Polyarctique-Groupe Taitbout; Rhumatisme et Travail; Arthritis Research Campaign; Unversity of Minnesota; Minnesota Supercomputing Institute; National Institute of General Medical Sciences (R01 GM31575