Back to Search
Start Over
Use of axial tomography to follow temporal changes of benthic communities in an unstable sedimentary environment (Baie des Ha! Ha!, Saguenay Fjord)
- Source :
- Journal of Experimental Marine Biology and Ecology, Journal of Experimental Marine Biology and Ecology, 2003, vol. 285-286, pp. 265-282. ⟨10.1016/S0022-0981(02)00532-4⟩, ResearcherID, Journal of Experimental Marine Biology and Ecology, Elsevier, 2003, vol. 285-286, pp. 265-282. ⟨10.1016/S0022-0981(02)00532-4⟩
- Publication Year :
- 2003
- Publisher :
- HAL CCSD, 2003.
-
Abstract
- International audience; In the upper layer of the sediment column, organic matter recycling is greatly influenced by bioturbation. However, there are many physical changes in the nature of the sediment that may disturb benthic communities and create a biogeochemical imbalance. Following a very heavy rainfall between 26 and 29 July 1996, an intense flash flood in the Saguenay Fjord caused discharges of 6 million cubic metres of sediments into Baie des Ha! Ha!. Unstable sediment deposits located at the top of the delta of the Rivie're des Ha! Ha! were sporadically exported to the deep basin. After this physical disturbance, meiobenthic and macrobenthic organisms progressively re-colonised the sediment column. To determine the impacts of such sedimentary depositions on benthic fauna, two stations, one at the head and one at the mouth of the Baie des Ha! Ha!, have been monitored since 1996. During this survey, we developed a new method for the quantification of biogenic structures using computer axial tomography (CAT-Scan). Benthic fauna analysis showed that the two stations were characterised by different temporal changes in the benthic dynamics according to their geographic location. Using CAT-Scan analysis of sediment cores, we were able to characterise the stability of the sediment column for the two stations in 1999 and 2000. Scan results suggest that colonisation processes were closely linked with the stability of the sediment column. Erosion and redeposition of surficial sediments caused a succession in the formation of biogenic structures. These variations were characterised for the first time using CAT-Scan, which is a nondestructive, rapid, and precise method. Tomographic analysis showed the importance of the production and destruction rates of biogenic structures and the sedimentation rate for the preservation of burrows and potentially reactive components. This study finally demonstrated that each erosional event could be followed by a rapid formation of biogenic structures, allowing the re-oxidation of old deposits.
- Subjects :
- 0106 biological sciences
Biogeochemical cycle
010504 meteorology & atmospheric sciences
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Fjord
Aquatic Science
Biology
01 natural sciences
Sciences de la Terre
Sedimentary depositional environment
Benthic communities
Sediment–water interface
Computer axial tomography
Large-scale disturbance
14. Life underwater
Ecology, Evolution, Behavior and Systematics
0105 earth and related environmental sciences
geography
geography.geographical_feature_category
Ecology
010604 marine biology & hydrobiology
Sediment
Oceanography
Biogenic structures
13. Climate action
Benthic zone
Sedimentary rock
Bioturbation
Subjects
Details
- Language :
- English
- ISSN :
- 00220981
- Database :
- OpenAIRE
- Journal :
- Journal of Experimental Marine Biology and Ecology, Journal of Experimental Marine Biology and Ecology, 2003, vol. 285-286, pp. 265-282. ⟨10.1016/S0022-0981(02)00532-4⟩, ResearcherID, Journal of Experimental Marine Biology and Ecology, Elsevier, 2003, vol. 285-286, pp. 265-282. ⟨10.1016/S0022-0981(02)00532-4⟩
- Accession number :
- edsair.doi.dedup.....8982afed5bfa645c49d4b72c1fc41b87
- Full Text :
- https://doi.org/10.1016/S0022-0981(02)00532-4⟩