Effects of suspended sediments on the sponge holobiont with implications for dredging management

Mari Carmen Pineda*, Brian Strehlow, Miriam Sternel, Alan Duckworth, Ross Jones, Nicole S. Webster

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

34 Downloads (Pure)

Abstract

Dredging can cause high suspended sediment concentrations (SSC) in the water column, posing a hazard to filter feeding organisms like sponges as sediment may clog their aquiferous systems and reduce feeding. In order to provide pressure-response values for sponges to SSC and tease apart the cause:effect pathways of dredging pressures, five heterotrophic and phototrophic species were experimentally exposed to a range of dredging-relevant SSC of up to 100 mg L-1, with light compensation across treatments to ensure that SSC was the primary physical parameter. This study shows that some sponge species exposed to high SSC (≥23 mg L-1) for extended periods (28 d) have lower survival, increased necrosis and depletion of energy reserves. In contrast, SSC of ≤10 mg L-1 caused few, if any, negative effects and is thus suggested as a prudent sub-lethal threshold for sponges. Microbial communities did not change significantly among SSC treatments, although a nutritional shift from mixotrophy towards increased phototrophy was detected for some sponge species exposed to high SSC. Importantly however, it is expected that the combined effect of SSC with low light availability and sediment smothering as occurs during dredging operations will increase the negative effects on sponges.

Original languageEnglish
Article number4925
JournalScientific Reports
Volume7
Number of pages15
ISSN2045-2322
DOIs
Publication statusPublished - 2017
Externally publishedYes

Fingerprint

Dive into the research topics of 'Effects of suspended sediments on the sponge holobiont with implications for dredging management'. Together they form a unique fingerprint.

Cite this