Biodiversity, ecosystem engineering, and trophic ecology of whale-bone and wood-fall habitats in the deep NE Pacific: A controlled experimental approach

Simple item page
dc.contributor.advisor Smith, Craig R.
dc.contributor.author Young, Emily Louise
dc.contributor.department Oceanography
dc.date.accessioned 2023-07-11T00:20:27Z
dc.date.available 2023-07-11T00:20:27Z
dc.date.issued 2023
dc.description.degree Ph.D.
dc.identifier.uri https://hdl.handle.net/10125/105101
dc.subject Biological oceanography
dc.subject biodiversity
dc.subject deep sea
dc.subject ecology
dc.subject organic falls
dc.subject whale bone
dc.subject wood
dc.title Biodiversity, ecosystem engineering, and trophic ecology of whale-bone and wood-fall habitats in the deep NE Pacific: A controlled experimental approach
dc.type Thesis
dcterms.abstract Organic-fall habitat islands are established when large organic-rich parcels, such as whale bones or wood, sink to the generally food-poor deep-sea floor. Organic-fall communities may pass through a succession of ecological stages, modulated by key ecosystem engineers that influence the availability of habitat and food resources in these ecosystems. Because biodiversity and ecosystem functions at organic falls are likely to vary with substrate type, size, and deployment times, comparisons between ocean regions and depths are problematic. In this study, a replicated experimental approach has been used to control the effects of substrate type, size, and deployment times. Three major aspects of organic-fall ecology were explored: patterns and drivers of biodiversity, the importance of a wood-boring ecosystem engineer to ecosystem structure and function, and variations in trophic structure between whale-bone and wood-fall assemblages. Four benthic landers containing replicate whale-bone, wood, and inorganic control substrates were concurrently deployed for 15 months on the Washington-Oregon margin; two each at depths of ~1600 and ~2800 m, separated by distances of > 200 km. Whale-bone, wood, and inorganic substrates supported assemblages with different community structures, even within landers. Community composition was significantly different between depths and between landers within a depth, indicating variability on bathymetric and regional scales. Wood blocks at ~1600 m were heavily degraded by wood-boring xylophagaid bivalves, which consumed up to ~90% of wood-block mass. Xylophagaid boring and defecation increased habitat availability and complexity as well as the range of nutritional niches; this led to a high abundance of macrofauna inhabiting the borings inside the wood. Xylophagaid colonization was absent to mild in deeper wood blocks at sites further offshore, which we hypothesize results partly from lower propagule supply at increased distances from terrestrial forests. Bulk stable isotope analyses revealed that co-located whale-bone and wood assemblages had different trophic structures. Whale-bone and wood were dominant basal food sources; however, the relative importance of background particulate organic matter (POM) to faunal diets varied among taxa, functional groups, and between whale-bone and wood substrates, with background POM less important on wood. We hypothesize that labile particulate organic material in xylophagaid feces provides an especially important food resource at wood falls. This dissertation provides deeper insight into drivers of variability and quantifies some important aspects of organic-fall ecology.
dcterms.language en
dcterms.publisher University of Hawai'i at Manoa
dcterms.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.type Text
local.identifier.alturi http://dissertations.umi.com/hawii:11652
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Young_hawii_0085A_11652.pdf
Size:
4.37 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Ph.D. - Oceanography