Event Title

Differences in stressor intensity and plant condition in South Puget Sound bull kelp forests

Streaming Media

Presentation Abstract

The shorelines of British Columbia and Washington support more than 20 species of kelp, which create critical biogenic habitat. Within the majority of the Salish Sea, bull kelp (Nereocystis luetkeana) is the sole kelp species that forms a floating canopy. Its abundance in the Salish Sea appears to be declining, but little research exists on bull kelp within this inland sea where environmental conditions are distinct from the exposed coast. This presentation evaluates bull kelp and environmental conditions in South Puget Sound. We monitored bull kelp morphology, including blade length, blade number, bulb diameter, endo/epiphyte cover, physical damage, and plant density. We also assessed stressors known to impact bull kelp condition, including temperature, nitrate availability, light attenuation, suspended sediment concentration and densities of the native kelp crab Pugettia producta. Generally, stressor intensity increased along a geographic gradient into the interior of South Puget Sound and was inversely correlated with plant condition. High temperatures and crab densities were correlated with significant declines in blade length over the summer growing season. The bed exposed to the highest temperatures and crab densities was characterized by significantly lower densities of plants. In addition to this general pattern of increasing stressors and decreasing kelp condition, notable exceptions underscore the importance of other, unmeasured factors. Overall, these data sets provide preliminary glimpses into the relationship between kelp condition and stressors in an area of concern.

Session Title

Session 2.2A: Kelp: Stressors, Trends, and Value (Part II)

Conference Track

Kelp & Seagrass

Conference Name

Salish Sea Ecosystem Conference (2020 : Online)

Document Type

Event

SSEC Identifier

2020_abstractID_1269

Start Date

22-4-2020 12:30 PM

End Date

22-4-2020 2:00 PM

Genre/Form

conference proceedings; presentations (communicative events)

Subjects – Topical (LCSH)

Kelp bed ecology--Salish Sea (B.C. and Wash.); Kelps--Effect of stress on--Salish Sea (B.C. and Wash.); Environmental monitoring--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

Format

application/pdf

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Apr 22nd, 12:30 PM Apr 22nd, 2:00 PM

Differences in stressor intensity and plant condition in South Puget Sound bull kelp forests

The shorelines of British Columbia and Washington support more than 20 species of kelp, which create critical biogenic habitat. Within the majority of the Salish Sea, bull kelp (Nereocystis luetkeana) is the sole kelp species that forms a floating canopy. Its abundance in the Salish Sea appears to be declining, but little research exists on bull kelp within this inland sea where environmental conditions are distinct from the exposed coast. This presentation evaluates bull kelp and environmental conditions in South Puget Sound. We monitored bull kelp morphology, including blade length, blade number, bulb diameter, endo/epiphyte cover, physical damage, and plant density. We also assessed stressors known to impact bull kelp condition, including temperature, nitrate availability, light attenuation, suspended sediment concentration and densities of the native kelp crab Pugettia producta. Generally, stressor intensity increased along a geographic gradient into the interior of South Puget Sound and was inversely correlated with plant condition. High temperatures and crab densities were correlated with significant declines in blade length over the summer growing season. The bed exposed to the highest temperatures and crab densities was characterized by significantly lower densities of plants. In addition to this general pattern of increasing stressors and decreasing kelp condition, notable exceptions underscore the importance of other, unmeasured factors. Overall, these data sets provide preliminary glimpses into the relationship between kelp condition and stressors in an area of concern.