Flushing submarine canyons

被引:634
作者
Canals, Miquel [1 ]
Puig, Pere
de Madron, Xavier Durrieu
Heussner, Serge
Palanques, Albert
Fabres, Joan
机构
[1] Univ Barcelona, Dept Stratig Paleontol & Marine Geosci, CRG Marine Geosci, E-08028 Barcelona, Spain
[2] CSIC, Inst Marine Sci, E-08003 Barcelona, Spain
[3] Univ Perpignan, CEFREM, CNRS, UMR 5110, F-66860 Perpignan, France
关键词
D O I
10.1038/nature05271
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The continental slope is a steep, narrow fringe separating the coastal zone from the deep ocean. During low sea- level stands, slides and dense, sediment- laden flows erode the outer continental shelf and the continental slope, leading to the formation of submarine canyons that funnel large volumes of sediment and organic matter from shallow regions to the deep ocean (1). During high sea-level stands, such as at present, these canyons still experience occasional sediment gravity flows(2 - 5), which are usually thought to be triggered by sediment failure or river flooding. Here we present observations from a submarine canyon on the Gulf of Lions margin, in the northwest Mediterranean Sea, that demonstrate that these flows can also be triggered by dense shelf water cascading ( DSWC) - a type of current that is driven solely by seawater density contrast. Our results show that DSWC can transport large amounts of water and sediment, reshape submarine canyon floors and rapidly affect the deep- sea environment. This cascading is seasonal, resulting from the formation of dense water by cooling and/ or evaporation, and occurs on both high- and low- latitude continental margins(6 - 8). DSWC may therefore transport large amounts of sediment and organic matter to the deep ocean. Furthermore, changes in the frequency and intensity of DSWC driven by future climate change may have a significant impact on the supply of organic matter to deep- sea ecosystems and on the amount of carbon stored on continental margins and in ocean basins.
引用
收藏
页码:354 / 357
页数:4
相关论文
共 29 条
[1]   DOC dynamics in the northwestern Mediterranean Sea (DYFAMED site) [J].
Avril, B .
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, 2002, 49 (11) :2163-2182
[2]   Deep water in the western Mediterranean: peculiar 1999 and 2000 characteristics, shelf formation hypothesis, variability since 1970 and geochemical inferences [J].
Bethoux, JP ;
de Madron, XD ;
Nyffeler, F ;
Tailliez, D .
JOURNAL OF MARINE SYSTEMS, 2002, 33 :117-131
[3]   HTCO METHOD FOR DISSOLVED ORGANIC-CARBON ANALYSIS IN SEAWATER - INFLUENCE OF CATALYST ON BLANK ESTIMATION [J].
CAUWET, G .
MARINE CHEMISTRY, 1994, 47 (01) :55-64
[4]   Sediment gravity flow - the conceptual problems [J].
Dasgupta, P .
EARTH-SCIENCE REVIEWS, 2003, 62 (3-4) :265-281
[5]   Comments on "Cascades of dense water around the world ocean" [J].
de Madron, XD ;
Zervakis, V ;
Theocharis, A ;
Georgopoulos, D .
PROGRESS IN OCEANOGRAPHY, 2005, 64 (01) :83-90
[6]  
*EARTH RES INF SYS, 1996, GLOB 30 ARC SEC EL D
[7]  
FLOOD RD, 1983, GEOL SOC AM BULL, V94, P630, DOI 10.1130/0016-7606(1983)94<630:COSFAA>2.0.CO
[8]  
2
[9]   ABYSSAL BEDFORMS AS INDICATORS OF CHANGING BOTTOM CURRENT FLOW - EXAMPLES FROM THE US EAST-COAST CONTINENTAL RISE [J].
FLOOD, RD .
PALEOCEANOGRAPHY, 1994, 9 (06) :1049-1060
[10]   A model intercomparison of changes in the Atlantic thermohaline circulation in response to increasing atmospheric CO2 concentration -: art. no. L12703 [J].
Gregory, JM ;
Dixon, KW ;
Stouffer, RJ ;
Weaver, AJ ;
Driesschaert, E ;
Eby, M ;
Fichefet, T ;
Hasumi, H ;
Hu, A ;
Jungclaus, JH ;
Kamenkovich, IV ;
Levermann, A ;
Montoya, M ;
Murakami, S ;
Nawrath, S ;
Oka, A ;
Sokolov, AP ;
Thorpe, RB .
GEOPHYSICAL RESEARCH LETTERS, 2005, 32 (12) :1-5