The puzzle of declining benthic invertebrate communities – could high organic matter deposition have a role?
Presentation Abstract
Decades of monitoring by the Dept. of Ecology has documented declines in Puget Sound benthic communities; however, the deterioration of benthic communities does not correspond well with changes in individual chemical contaminants measured or laboratory tests for sediment toxicity. The spatial distribution of benthic communities is partly defined by the physical and oceanographic habitat, including delivery of nutrient-rich particles to the sediment. New measurements of total organic carbon, total nitrogen, and particle size indicate that organic matter accumulates preferentially in terminal inlets. Carbon and nitrogen content increases with the fraction of fine sediments (silt plus clay), which also tends to be high in low-energy environments such as terminal inlets. Total carbon and nitrogen in surface sediments are strongly positively correlated, indicating that sediment nitrogen is primarily organic in origin and that the carbon and nitrogen supplies are controlled by similar processes. In an effort to understand the declines in benthic communities, this presentation will explore the spatial concordance between locations with high levels of organic matter in sediments and adversely affected benthic communities.
Session Title
Session 1.1B: The Environmental Toxicology and Chemistry of the Salish Sea Ecosystem
Conference Track
Contaminants, Plastics, Microplastics, Toxicology & Stormwater
Conference Name
Salish Sea Ecosystem Conference (2020 : Online)
Document Type
Event
SSEC Identifier
2020_abstractID_4419
Start Date
21-4-2020 10:30 AM
End Date
21-4-2020 12:00 PM
Genre/Form
conference proceedings; presentations (communicative events)
Subjects – Topical (LCSH)
Benthic animals--Ecology--Salish Sea (B.C. and Wash.); Invertebrate populations--Salish Sea (B.C. and Wash.); Invertebrate communities--Salish Sea (B.C. and Wash.); Organic water pollutants--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
The puzzle of declining benthic invertebrate communities – could high organic matter deposition have a role?
Decades of monitoring by the Dept. of Ecology has documented declines in Puget Sound benthic communities; however, the deterioration of benthic communities does not correspond well with changes in individual chemical contaminants measured or laboratory tests for sediment toxicity. The spatial distribution of benthic communities is partly defined by the physical and oceanographic habitat, including delivery of nutrient-rich particles to the sediment. New measurements of total organic carbon, total nitrogen, and particle size indicate that organic matter accumulates preferentially in terminal inlets. Carbon and nitrogen content increases with the fraction of fine sediments (silt plus clay), which also tends to be high in low-energy environments such as terminal inlets. Total carbon and nitrogen in surface sediments are strongly positively correlated, indicating that sediment nitrogen is primarily organic in origin and that the carbon and nitrogen supplies are controlled by similar processes. In an effort to understand the declines in benthic communities, this presentation will explore the spatial concordance between locations with high levels of organic matter in sediments and adversely affected benthic communities.
