A rosette system for the collection of trace metal clean seawater

Hunter, Craig N.; Gordon, R. Michael; Fitzwater, Steve E.; Coale, Kenneth H.

doi:10.4319/lo.1996.41.6.1367

Cited by 32 publications

(15 citation statements)

References 11 publications

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“…Water samples were collected using a trace metal clean rosette (Hunter et al 1996). Stations were denoted as being inside the patch (IN stations) or outside the patch (OUT stations) using SF 6 concentration as a proxy for iron concentration.…”

Section: Methodsmentioning

confidence: 99%

“…Southern Ocean iron enrichment experiments are often viewed as analogues of conditions during glacial times when dust-borne Fe inputs to the area were much larger (Coale et al 1996(Coale et al , 2004Boyd et al 2000;Hutchins et al 2001;Smetacek 2001). To interpret our results in the context of such long time scales, the zonal circulation patterns that link the nutrient dynamics of the Antarctic and Subantarctic must be considered.…”

mentioning

confidence: 99%

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Control of silica production by iron and silicic acid during the Southern Ocean Iron Experiment (SOFeX)

Brzezinski

Jones

Demarest

2005

Limnology & Oceanography

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We examined the role of Si limitation in mediating the response of siliceous biomass and silica production to mesoscale Fe fertilization in the high-silicic acid high-nitrate waters of the Antarctic and in the low-silicic acid high-nitrate waters of the Subantarctic during austral summer. Iron fertilization stimulated biogenic silica production and silicic acid depletion in both regions. Si limitation significantly curtailed the response of silica production to Fe in the Subantarctic, but not in the Antarctic. Additions of silicic acid to Fe-enriched waters of the Subantarctic more than doubled specific silica production rates beyond the increase caused by Fe alone. This result, combined with the presence of Si limitation both inside and outside of the fertilized patch in the Subantarctic, indicates that silica production in the Subantarctic is regulated by both Fe and Si during austral summer. Fe increased the ability of Subantarctic diatom assemblages to take up low concentrations of Si over an order of magnitude by increasing maximum uptake rates and lowering half-saturation constants for silicic acid uptake. Our observations indicate that the dramatic gradient in Si availability across the Antarctic Circumpolar Current exerts a strong control on the contribution of diatoms to new production following Fe enrichment in the Southern Ocean during austral summer. With sufficient Fe to allow nitrate depletion, the abundant silicic acid in the Antarctic would allow diatoms to dominate nitrate use; however, low silicic acid concentrations in the Subantarctic would restrict the fraction of available nitrate that would be consumed by diatoms to ca. 5%.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Control of silica production by iron and silicic acid during the Southern Ocean Iron Experiment (SOFeX)

Brzezinski

Jones

Demarest

2005

Limnology & Oceanography

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“…Both ships sampled using traditional CTD-Rosette systems as well as trace metalclean rosettes (Hunter et al, 1997). Given the hypothesized importance of trace metals in waters of the Southern Ocean (e.g., Martin et al, 1990;de Baar et al, 1995), it was essential to the project that all samples in which biological rates were determined be sampled without contamination.…”

Section: Study Areamentioning

confidence: 99%

The US Southern Ocean Joint Global Ocean Flux Study: an introduction to AESOPS

Smith

Anderson

Moore

et al. 2000

Deep Sea Research Part II: Topical Studies in Oceanography

120

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The United States Southern Ocean Joint Global Ocean Flux Study (JGOFS), also known as AESOPS (Antarctic Environment and Southern Ocean Process Study), focused on two distinct regions. The "rst was the Ross-Sea continental shelf, where a series of six cruises collected a variety of data from October 1996 through February 1998. The second area was the southwest Paci"c sector of the Southern Ocean, spanning the Antarctic Circumpolar Current (ACC) at &1703W. Data were collected within this region during "ve cruises from September 1996 through March 1998, as well as during selected transits between New Zealand and the Ross Sea. The "rst results of these cruses are described in this issue. The Ross-Sea investigation extensively sampled the area along 76330 S to elucidate the temporal patterns and processes that contribute to making this one of the Antarctic's most productive seas. Hydrographic distributions con"rm that strati"cation is initiated early in October within the polynya, generating an environment that is favorable for phytoplankton growth. Signi"cant spatial variations in mixed-layer depths, the timing of the onset of strati"cation, and the strength of the strati"cation existed throughout the growing season. Nutrient concentrations re#ected phytoplankton uptake, and reached their seasonal minimal in early February. Chlorophyll concentrations were maximal in early January, whereas productivity was maximal in late November, which re#ects the temporal uncoupling between growth and biomass accumulation in the region. Independent estimates of biogenic export suggest that majority of the #ux occurred in late summer and was strongly uncoupled from phytoplankton growth. The ACC region exhibited seasonal changes that in some cases were greater than those observed in the Ross Sea.0967-0645/00/$ -see front matter 2000 Published by Elsevier Science Ltd. PII: S 0 9 6 7 -0 6 4 5 ( 0 0 ) 0 0 0 5 9 -X Sea ice covered much of the region south of the Polar Front in winter, and retreated rapidly in late spring and early summer. Mixed layers throughout the region shoaled in summer due to surface heating, while the addition of freshwater from melting sea ice enhanced strati"cation in the Seasonal Ice Zone, creating conditions favorable for phytoplankton growth. For example, silicic acid concentrations decreased from initial values as high as 65 to less than 2 M within approximately 100 km (from 65.7 to 64.83S). Fluorescence values, however, showed less than a two-fold variation over the same distance. The vertical #ux of carbon in the Polar Front area is substantial, and marked variations in the composition of exported material exited over the region. The results provide a means whereby the controls of phytoplankton growth and organic matter #ux and remineralization can be analyzed in great detail. Additional results of the AESOPS project are discussed.

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“…In the Arabian Sea Expedition, a Moss Landing Marine Laboratories trace-metal clean (TMC) rosette with General Oceanics Go-Flo2+ sample bottles and a Kevlar cable (Sanderson et al, 1995;Hunter et al, 1996) was used for water collection on all six process cruises with the exception of the second half of the July/August mid-SW Monsoon cruise (TN049). Due to the loss of the TMC rosette midway through the TN049 cruise, an epoxy-coated rosette was used for the remainder of the cruise; a replacement TMC rosette was obtained for the remaining cruises.…”

Section: Primary Productivitymentioning

confidence: 99%