Particulate biogenic silica and carbon production rates and particulate matter distribution in the Indian sector of the Subantarctic Ocean

Leblanc, Karine; Quéguiner, Bernard; Fiala, Michel; Blain, Stéphane; Morvan, J.; Corvaisier, Rudolph

doi:10.1016/s0967-0645(02)00078-4

Cited by 34 publications

(19 citation statements)

References 33 publications

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“…14 and 15), LSi concentrations fell in the same range of values previously measured in the Southern Ocean, both in the PFZ (Quéguiner et al, 1997;Quéguiner, 2001;Leblanc et al, 2002) and the POOZ (Quéguiner et al, 1997;. TNS-1 and R2 stations showed low LSi concentrations typically observed for regions far from continental influence (< 0.04 µmol L −1 ; Leblanc et al, 2002).…”

Section: Lsi As Tracer Of Lithogenic Matter Transport?supporting

confidence: 70%

“…The phytoplankton community structure is known to directly impact the fate of carbon through sinking rates depending on various factors such as cell size, ballast minerals, transparent exopolymers (TEP), or (re)packaging in zooplankton fecal pellets (Margalef, 1965;Falkowski et al, 2003;Legendre and Le Fèvre, 1989;Armstrong et al, 2009). Artificial and natural iron-fertilization experiments evidenced the preferential development of large diatoms (> 20 µm) under iron-replete conditions (Hutchins and Bruland, 1998;Takeda, 1998;Hare et al, 2005;Armand et al, 2008;Timmermans et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

et al. 2014

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Abstract. The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October-November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m −2 for chlorophyll a 314 to 744 mmol m −2 for biogenic silica (BSi), 1106 to 2268 mmol m −2 for particulate organic carbon, 215 to 436 mmol m −2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m −2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the polar front zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size-fractionation and high performance liquid chromatography (HPLC) pigment signatures, whereas the ironlimited reference area was associated with a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from most previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9, respectively) in the iron-fertilized areas compared to the iron-limited reference station (0.13, 1.1, and 5.8, respectively). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From particulate organic carbon (POC), particulate organic nitrogen (PON), and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the phytoplankton community structure as well as major changes in the nutrient stocks progressively leading to silicic acid exhaustion at the end of the productive season.Our observations suggest that the specific response of phytoplankton communities under natural iron fertilization is much more diverse than what has been regularly observed in artificial iron fertilization experiments and that the elemental composition of the bulk particulate matter reflects phytoplankton taxonomic structure rather than being a direct consequence of iron availability.

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Section: Lsi As Tracer Of Lithogenic Matter Transport?supporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

et al. 2014

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“…This feature has also been recurrently observed in the Southern Ocean but with often much higher biogenic silica concentrations (Quéguiner, 2001;Leblanc et al, 2002;Quéguiner and Brzezinski, 2002;Beucher et al, 2004;Mosseri et al, 2008).…”

Section: Occurrence Of a Deep Silica Maximum (Dsm) In The Mediterranesupporting

confidence: 58%

Deep silicon maxima in the stratified oligotrophic Mediterranean Sea

et al. 2011

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Abstract. The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco), and total chlorophyll-a (TChl-a) were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM) encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM), fucoxanthin (DFM) and TChl-a (DCM) were evidenced during both seasons with maximal concentrations of 0.45 µmol L −1 for BSi, 0.26 µg L −1 for Fuco, and 1.70 µg L −1 for TChl-a, all measured during summer. Contrary to the DCM which was a persistent feature in the Mediterranean Sea, the DSM and DFMs were observed in discrete areas of the Alboran Sea, the Algero-Provencal basin, the Ionian sea and the Levantine basin, indicating that diatoms were able to grow at depth and dominate the DCM under specific conditions. Diatom assemblages were dominated by Chaetoceros spp., Leptocylindrus spp., Pseudonitzschia spp. and the association between large centric diatoms (Hemiaulus hauckii and Rhizosolenia styliformis) and the cyanobacterium Richelia intracellularis Correspondence to: Y. Crombet (yann.crombet@univmed.fr) was observed at nearly all sites. The diatom's ability to grow at depth is commonly observed in other oligotrophic regions and could play a major role in ecosystem productivity and carbon export to depth. Contrary to the common view that Si and siliceous phytoplankton are not major components of the Mediterranean biogeochemistry, we suggest here that diatoms, by persisting at depth during the stratified period, could contribute to a large part of the marine primary production as observed in other oligotrophic areas.

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“…Biological activity was very low at that time of the year, as evidenced by the stronger dependence of pCO 2 on hydrological structures. These results are also confirmed by the low primary production rates measured during the cruise (Leblanc et al 2002). The present study period (January-February) marked the end of a productive period in that area, phytoplankton production being hindered by a combination of limiting resources including iron and silicic acid .…”

Section: Discussionsupporting

confidence: 85%

“…Particulate biogenic silica concentration in the surface waters was low and never exceeded 0.2 µmol l -1 , reflecting a weak diatom contribution to phytoplankton biomass. Data collected during the same cruise (Leblanc et al 2002) suggested that the BSi accumulation could be the result of a bloom preceding the cruise period and/or an allochtonous input by lateral advection. Phytoplankton cell numbers were low and picoplankton was dominant, a general feature observed in different seasons in the Southern Ocean .…”

Section: Discussionmentioning

confidence: 99%

Mesoscale surface distribution of biogeochemical characteristics in the Crozet Basin frontal zones (South Indian Ocean)

Fiala¹,

Delille²,

Dubreuil³

et al. 2003

Mar. Ecol. Prog. Ser.

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Particulate biogenic silica and carbon production rates and particulate matter distribution in the Indian sector of the Subantarctic Ocean

Cited by 34 publications

References 33 publications

Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

Deep silicon maxima in the stratified oligotrophic Mediterranean Sea

Mesoscale surface distribution of biogeochemical characteristics in the Crozet Basin frontal zones (South Indian Ocean)

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