Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada

被引:0
|
作者
Sharpe, Hannah [1 ]
Gosselin, Michel [2 ]
Lalande, Catherine [3 ]
Normandeau, Alexandre [4 ]
Montero-Serrano, Jean-Carlos [2 ]
Baccara, Khouloud [2 ]
Bourgault, Daniel [2 ]
Sherwood, Owen [5 ]
Limoges, Audrey [1 ]
机构
[1] Univ New Brunswick UNB, Dept Earth Sci, Fredericton, NB E3B 5A3, Canada
[2] Univ Quebec Rimouski UQAR, Inst Sci Mer Rimouski ISMER, Rimouski, PQ G5L 3A1, Canada
[3] Univ Laval, Amundsen Sci, Quebec City, PQ G1V 0A6, Canada
[4] Bedford Inst Oceanog, Geol Survey Canada Atlantic, Dartmouth, NS B2Y 4A2, Canada
[5] Dalhousie Univ, Dept Earth & Environm Sci, Halifax, NS B3H 4R2, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
PARTICULATE ORGANIC-MATTER; NITROGEN; NITRATE; CARBON; GULF; BIOGEOCHEMISTRY; PRESERVATION; ASSIMILATION; CHLOROPHYLL; VARIABILITY;
D O I
10.5194/bg-20-4981-2023
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Submarine canyons enhance shelf-slope sediment exchange and influence hydrodynamic processes, with consequences for biogeochemical cycles. This work documents variations in the vertical export of biogenic matter on the northern shore of the lower St. Lawrence Estuary (LSLE, Quebec, eastern Canada), which is characterized by the presence of an active submarine canyon system. A total of three moorings were deployed from November 2020 to September 2021. One nearshore mooring (PDMc) was deployed in the main axis of the Pointe-des-Monts (PDM) canyon system and was equipped with an acoustic Doppler current profiler (ADCP), and two moorings equipped with sediment traps were deployed in the distal PDM canyon system (PDM-154, PDM-224) and offshore Baie-Comeau (BC-133). The ADCP data revealed the occurrence of a minor sediment remobilization event (December 2020) and a small turbidity current (February 2021) in the canyon. Concurrent elevated fluxes of total particulate matter, particulate organic carbon, particulate nitrogen, and chloropigments showed that these events left a signature in sediment traps PDM-154 and PDM-224 located > 2.6 km further offshore by enhancing lateral dispersion of resuspended sediments. The composition of diatom and dinoflagellate assemblages was similar in the canyon system and offshore BC, but the diatom bloom occurred 2 weeks earlier (in mid-April) at the PDM site. A bloom of the potentially toxic diatom Pseudo-nitzschia seriata was also observed during the second half of September 2021 at the BC site. Annual diatom and dinoflagellate fluxes were almost 2 times lower at the PDM site than at the BC site, possibly due to differences in riverine input and the structure of the water column, as well as increased sediment input and resuspension at the PDM site, leading to limited light availability. This study notably helps identify the relationship between near-bed canyon processes and biogenic matter export in the water column, thereby directly influencing the ecosystem offshore PDM. The study period further covered an anomalously nearly ice-free winter, and thus, in the context of climate change, it provides valuable insight into future trends of biogenic matter export in the LSLE.
引用
收藏
页码:4981 / 5001
页数:21
相关论文
共 42 条
  • [1] Recent transfer of coastal sediments to the Laurentian Channel, Lower St. Lawrence Estuary (Eastern Canada), through submarine canyon and fan systems
    Hubert Gagné
    Patrick Lajeunesse
    Guillaume St-Onge
    Andrée Bolduc
    Geo-Marine Letters, 2009, 29 : 191 - 200
  • [2] Recent transfer of coastal sediments to the Laurentian Channel, Lower St. Lawrence Estuary (Eastern Canada), through submarine canyon and fan systems
    Gagne, Hubert
    Lajeunesse, Patrick
    St-Onge, Guillaume
    Bolduc, Andree
    GEO-MARINE LETTERS, 2009, 29 (03) : 191 - 200
  • [3] Submarine canyons and channels in the Lower St. Lawrence Estuary (Eastern Canada): Morphology, classification and recent sediment dynamics
    Normandeau, Alexandre
    Lajeunesse, Patrick
    St-Onge, Guillaume
    GEOMORPHOLOGY, 2015, 241 : 1 - 18
  • [4] Submarine mass movements in the Betsiamites area, Lower St. Lawrence Estuary, Quebec, Canada
    Cauchon-Voyer, Genevieve
    Locat, Jacques
    St-Onge, Guillaume
    SUBMARINE MASS MOVEMENTS AND THEIR CONSEQUENCES, 2007, 27 : 233 - +
  • [5] Characterization of suspended matter size and composition in the St. Lawrence Estuary (eastern Canada)
    Fabris, Anne-Sophie
    Larouche, Pierre
    Montero-Serrano, Jean-Carlos
    REGIONAL STUDIES IN MARINE SCIENCE, 2021, 45
  • [6] Morphodynamics in sediment-starved inner-shelf submarine canyons (Lower St. Lawrence Estuary, Eastern Canada)
    Normandeau, Alexandre
    Lajeunesse, Patrick
    St-Onge, Guillaume
    Bourgault, Daniel
    Drouin, Simon St-Onge
    Senneville, Simon
    Belanger, Simon
    MARINE GEOLOGY, 2014, 357 : 243 - 255
  • [7] Turbulent nitrate fluxes in the Lower St. Lawrence Estuary, Canada
    Cyr, Frederic
    Bourgault, Daniel
    Galbraith, Peter S.
    Gosselin, Michel
    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 2015, 120 (03) : 2308 - 2330
  • [8] Influence of lithostratigraphy on the retreat of an unconsolidated sedimentary coastal cliff (St. Lawrence estuary, eastern Canada)
    Joyal, Gabriel
    Lajeunesse, Patrick
    Morissette, Antoine
    Bernatchez, Pascal
    EARTH SURFACE PROCESSES AND LANDFORMS, 2016, 41 (08) : 1055 - 1072
  • [9] Absorption properties of phytoplankton in the Lower Estuary and Gulf of St. Lawrence (Canada)
    Roy, Suzanne
    Blouin, Frederick
    Jacques, Andre
    Therriault, Jean-Claude
    CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES, 2008, 65 (08) : 1721 - 1737
  • [10] The concept of an ecosystem approach applied to the Lower St. Lawrence estuary (Canada)
    Savenkoff, Claude
    Gagné, Jacques A.
    Gilbert, Michel
    Castonguay, Martin
    Chabot, Denis
    Chassé, Joël
    Comtois, Sophie
    Dutil, Jean-Denis
    Galbraith, Peter S.
    Gosselin, Jean-François
    Grégoire, François
    Larocque, Richard
    Larouche, Pierre
    Lavoie, Diane
    Lebeuf, Michel
    Lesage, Véronique
    Maps, Frédéric
    McQuinn, Ian H.
    Mosnier, Arnaud
    Nozères, Claude
    Ouellet, Patrick
    Plourde, Stéphane
    Sainte-Marie, Bernard
    Savard, Louise
    Scarratt, Michael
    Starr, Michel
    Environmental Reviews, 2017, 25 (01) : 26 - 96