Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Sediment resuspension: Impacts and extent of human disturbances
Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. (Marine ecotoxicology)
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Resuspension of sediment by anthropogenic disturbances is a concern due to the impacts it has on organisms and ecosystems. Bottom trawling is one major cause of sediment resuspension. A field study showed that a small trawl created a sediment plume 120 - 150 m wide and 15-18 m high (Paper 1). The sediment in the same study was highly contaminated. Blue mussels exposed to the sediment plume showed an increased uptake of contaminants and after 1 month reached levels toxic for human health (Paper 1). In the Baltic Proper, bottom trawling is the main cause of sediment suspension in waters >73 m, where resuspension by wind induced waves is minimal. Compared with dredging, bottom trawling annually resuspends 23-88 times more sediment in this area (Paper 4).

Bottom trawling is expanding to deeper waters where sediment resuspension is expected to have larger impacts on organisms compared with shallow water. Deep water sponges create important habitats that are attractive fishing grounds. A laboratory experiment (Paper 3) showed that deep water sponges had a rapid respiratory response to short exposure of elevated turbidity.

Boat activities in harbours are another major cause of sediment and contaminant remobilisation to the water column. A laboratory experiment showed that suspension of sediment with high TBT concentrations induced higher mortality in blue mussels, Mytilus edulis, and faster growth inhibition of the alga Ceramium tenuicorne than unsuspended sediment (Paper 2).

This thesis clearly shows that resuspension due to human activities, in particular bottom trawling, is widespread and can have impacts on a range of organisms. However, there are large differences in management of these activities as they are covered by different legislative frameworks. When managing dredging, it is the most cited concern, whereas it is not considered in the management of bottom trawling.

Place, publisher, year, edition, pages
Stockholm: Department of Ecology, Environment and Plant Sciences, Stockholm University , 2014. , 42 p.
National Category
Ecology
Research subject
Marine Ecotoxicology
Identifiers
URN: urn:nbn:se:su:diva-98640ISBN: 978-91-7447-842-6 (print)OAI: oai:DiVA.org:su-98640DiVA: diva2:687062
Public defence
2014-02-14, föreläsningssalen, Institutionen för ekologi, miljö och botanik, Lilla Frescativägen 5, Stockholm, 14:00 (English)
Opponent
Supervisors
Projects
Baltic Ecosystem Adaptive Management (BEAM)
Funder
Formas, 2006-1018
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 4: Manuscript.

Available from: 2014-01-23 Created: 2014-01-08 Last updated: 2014-01-24Bibliographically approved
List of papers
1. Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord
Open this publication in new window or tab >>Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord
Show others...
2012 (English)In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 170, 232-241 p.Article in journal (Refereed) Published
Abstract [en]

Sediments are sinks for contaminants in the world's oceans. At the same time, commercial bottom trawling is estimated to affect around 15 million km(2) of the world's seafloor every year. However, few studies have investigated whether this disturbance remobilises sediment-associated contaminants and, if so, whether these are bioavailable to aquatic organisms. This field study in a trawled contaminated Norwegian fjord showed that a single 1.8 km long trawl pass created a 3-5 million m(3) sediment plume containing around 9 t contaminated sediment; ie. 200 g dw m(-2) trawled, equivalent to c. 10% of the annual gross sedimentation rate. Substantial amounts of PCDD/Fs and non-ortho PCBs were released from the sediments, likely causing a semi-permanent contaminated sediment suspension in the bottom waters. PCDD/Fs from the sediments were also taken up by mussels which, during one month, accumulated them to levels above the EU maximum advised concentration for human consumption.

Keyword
Sediment resuspension, Bottom trawling, Contaminant, Bioavailability, Blue mussel, SPMD
National Category
Environmental Sciences
Identifiers
urn:nbn:se:su:diva-82144 (URN)10.1016/j.envpol.2012.06.019 (DOI)000308450100029 ()
Note

AuthorCount:8;

Available from: 2012-11-09 Created: 2012-11-08 Last updated: 2017-12-07Bibliographically approved
2. Suspension of TBT-contaminated sediment causes physiologicalstress in macroalgae and blue mussels
Open this publication in new window or tab >>Suspension of TBT-contaminated sediment causes physiologicalstress in macroalgae and blue mussels
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Tributyltin is a toxic compound that has been used in antifouling paint for boats andships. Due to the immediate toxic effects at very low concentrations it was banned in many countries in 1986. Due to its slow degradation it is expected to be stored in the sediment for many decades. This experiment simulated a small boat harbour with frequent resuspension events of TBT-contaminated sediment to measure the impacts onthe release, bioavailability and effects of tributyltin. Physiological stress responses were measured in two coastal species, the blue mussel, Mytilus edulis, and the red algaCeramium tenuicorne. Response variables measured were respiration, ammonia excretion, clearance rate and survival rate (for mussels) and growth inhibition (for thealga). Resuspension released both dissolved and particle-bound TBT to the surrounding water and made it bioavailable for both organisms. There was a clear toxic effect of the highest concentrations and it was evident that both mussels and algae showed a fasterand more negative response when the sediment was suspended. Repeated or continuous exposure to suspended TBT-contaminated sediment can exert a risk to the organisms living in environments such as harbours.

National Category
Ecology
Research subject
Marine Ecotoxicology
Identifiers
urn:nbn:se:su:diva-98407 (URN)
Projects
Baltic Ecosystem Adaptive Management, BEAM
Funder
Formas, 2006-1018
Available from: 2014-01-08 Created: 2014-01-06 Last updated: 2014-01-14Bibliographically approved
3. Rapid respiratory responses of the deep-water sponge Geodia barretti exposed to suspended sediments
Open this publication in new window or tab >>Rapid respiratory responses of the deep-water sponge Geodia barretti exposed to suspended sediments
2013 (English)In: Aquatic Biology, ISSN 1864-7782, E-ISSN 1864-7790, Vol. 19, no 1, 65-73 p.Article in journal (Refereed) Published
Abstract [en]

Sponges often dominate deep-water benthic faunal communities and can comprise up to 90% of the benthic biomass. Due to the large amount of water that they filter daily, sponges are an important link between benthic and pelagic ecosystems. Across the Tromso-flaket, Barents Sea, Norway, there are high biomasses of deep-water sponges. This area is also an important fishing ground, with fishing activity in some areas >27000 trawl hours yr(-1). Bottom trawling suspends large quantities of sediment into the water column, with measured concentrations up to 500 mg l(-1). This is the first study on the effects of suspended sediment exposure on deep-water sponges. In a laboratory experiment, Geodia barretti (Bowerbank 1858) (Class: Demospongiae) was exposed to 5 different sediment concentrations (0, 10, 50, 100 and 500 mg l(-1)). Respiration rates were measured before, during and after the exposure period. The results demonstrate that G. barretti physiologically shuts down when exposed to concentrations of 100 mg l(-1) (86% reduction in respiration), with thresholds of responses occurring between 10 to 50 mg l(-1). However, rapid recovery to initial respiration levels directly after the exposure indicates that G. barretti can cope with a single short exposure to elevated sediment concentrations. Given the high bottom-trawling frequency in Tromso-flaket, sponges may be frequently exposed to suspended sediments. Therefore, it is important that further investigations on the effects of suspended sediments on filter feeding organisms focus on the effects of repeated and long-term suspended sediment exposures to evaluate the overall ecological impacts.

Keyword
Continental shelf, Porifera, Turbidity, Bottom trawling, Fisheries
National Category
Biological Sciences
Identifiers
urn:nbn:se:su:diva-94871 (URN)10.3354/ab00522 (DOI)000324199700007 ()
Note

AuthorCount:4;

Available from: 2013-10-16 Created: 2013-10-16 Last updated: 2017-12-06Bibliographically approved
4. The extent of sediment resuspension caused by bottom trawling, storms, and dredging in the Baltic Proper
Open this publication in new window or tab >>The extent of sediment resuspension caused by bottom trawling, storms, and dredging in the Baltic Proper
(English)Manuscript (preprint) (Other (popular science, discussion, etc.))
Abstract [en]

This study compares the extent and frequency of seafloor disturbances due to anthropogenic processes (bottom trawling and dredging) with those due to wind-driven waves in the Baltic Proper. There is little overlap between areas affected by bottom trawlers and naturally from waves, and bottom trawling is the main cause of sediment resuspension at greater (>73m) depths. Swedish bottom trawlers annually suspend between 3.8 and 13.6 M tonnes in this area, while from the reported dredging projects (reported between 2007 and 2009) the estimated maximum annual spillage was 0.14 M tonnes. The dominance of bottom trawling as a factor suspending sediment is clear, but management approaches for bottom trawling and dredging are different, despite similar expected effects on organisms and the environment. 

Keyword
Baltic Sea, sediment resuspension, natural disturbance, anthropogenic disturbance, fisheries management, seafloor integrity
National Category
Ecology
Research subject
Marine Ecology
Identifiers
urn:nbn:se:su:diva-98408 (URN)
Projects
Baltic Ecosystem Adaptive Management, BEAM
Funder
Formas, 2006-1018
Available from: 2014-01-08 Created: 2014-01-06 Last updated: 2014-01-14Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Tjensvoll, Ingrid
By organisation
Department of Ecology, Environment and Plant Sciences
Ecology

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 935 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf