Abstract Title

Session S-01G: New Strategies for Shorelines

Proposed Abstract Title

Subtidal riprap in Puget Sound: Its ecological structure and function, and its impact on adjacent soft sediment environments

Presenter/Author Information

Eliza HeeryFollow

Keywords

Shorelines

Location

Room 6C

Start Date

1-5-2014 5:00 PM

End Date

1-5-2014 6:30 PM

Description

In the past decade, several studies have examined the effects of coastal defense structures, such as riprap, in the intertidal zone in Puget Sound. However, these structures commonly extend well below the intertidal. In subtidal environments, very little is known about the ecological structure, function, and processes on riprap. We conducted photo surveys in the Seattle area to characterize the community composition on subtidal riprap installations. Subtidal riprap was dominated by a wide variety of red algae species and sessile invertebrate fauna. The community on subtidal riprap was not typical of that that observed on natural rocky substrates in the region. We also conducted sediment surveys, which revealed that biogenic materials from subtidal riprap installations were readily incorporated into sediments immediately adjacent to riprap. Two types of biogenic material were particularly common: (1) shell hash from Balanus sp., Pododesmus machrochisma, and other rocky sessile invertebrates, and (2) small pieces of red algae. The density of these materials decreased significantly with increasing distance from subtidal riprap, and may influence the community composition of infauna in surrounding sediments. While previous studies in the intertidal have emphasized the importance of intertidal riprap in altering erosive forces in surrounding habitats, subtidal riprap may serve as growing medium for biogenic materials and resources that subsidize adjacent soft sediment communities.

This document is currently not available here.

Share

COinS
 
May 1st, 5:00 PM May 1st, 6:30 PM

Subtidal riprap in Puget Sound: Its ecological structure and function, and its impact on adjacent soft sediment environments

Room 6C

In the past decade, several studies have examined the effects of coastal defense structures, such as riprap, in the intertidal zone in Puget Sound. However, these structures commonly extend well below the intertidal. In subtidal environments, very little is known about the ecological structure, function, and processes on riprap. We conducted photo surveys in the Seattle area to characterize the community composition on subtidal riprap installations. Subtidal riprap was dominated by a wide variety of red algae species and sessile invertebrate fauna. The community on subtidal riprap was not typical of that that observed on natural rocky substrates in the region. We also conducted sediment surveys, which revealed that biogenic materials from subtidal riprap installations were readily incorporated into sediments immediately adjacent to riprap. Two types of biogenic material were particularly common: (1) shell hash from Balanus sp., Pododesmus machrochisma, and other rocky sessile invertebrates, and (2) small pieces of red algae. The density of these materials decreased significantly with increasing distance from subtidal riprap, and may influence the community composition of infauna in surrounding sediments. While previous studies in the intertidal have emphasized the importance of intertidal riprap in altering erosive forces in surrounding habitats, subtidal riprap may serve as growing medium for biogenic materials and resources that subsidize adjacent soft sediment communities.