ANALYSIS OF PYRETHROIDS IN SEDIMENT PORE WATER BY SOLID-PHASE MICROEXTRACTION

2007 ◽  
Vol 26 (12) ◽  
pp. 2587 ◽  
Author(s):  
Svetlana Bondarenko ◽  
Frank Spurlock ◽  
Jianying Gan
Keyword(s):  
Pore Water ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Sediment Pore Water

MEASURING PYRETHROIDS IN SEDIMENT PORE WATER USING MATRIX-SOLID PHASE MICROEXTRACTION

2009 ◽  
Vol 28 (1) ◽  
pp. 36 ◽  
Author(s):  
Wesley Hunter ◽  
Yu Yang ◽  
Fredrik Reichenberg ◽  
Philipp Mayer ◽  
Jianying Gan
Keyword(s):  
Pore Water ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Sediment Pore Water

scholarly journals Stable Silicon Isotopes Uncover a Mineralogical Control on the Benthic Silicon Cycle in the Arctic Barents Sea

2021 ◽  
Author(s):  
James Ward ◽  
Katharine Hendry ◽  
Sandra Arndt ◽  
Johan Faust ◽  
Felipe Freitas ◽  
...  
Keyword(s):  
Pore Water ◽  
Phytoplankton Community ◽  
Barents Sea ◽  
Solid Phase ◽  
The Arctic ◽  
Lower Latitude ◽  
Sediment Pore Water ◽  
Mass Balance Calculation ◽  
Silicon Isotopes ◽  
Phytoplankton Communities

Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Moreover, further expansion of the Atlantic realm (termed `Atlantification') is expected to shift phytoplankton community compositions away from diatom-dominated spring bloomsin favour of Atlantic flagellate species (coccolithophore-dominated). The changes in pelagic primary production will alter the composition of the material comprising the depositional flux, which will subsequently in influence the recycling processes at and within the seafloor. In this study we assess the predominant controls on the early diagenetic cycling of Si, a key nutrient in marine ecosystems, by combining stable isotopic analysis of pore water DSi and of operationally defined reactive pools of the solid phase. We show that low biogenic silica (BSi) contents (0.39-0.52 wt% or 92-185 μmol g dry wt-1) drive correspondingly low asymptotic concentrations of pore water DSi (~100 μM). However, while these surface sediments appear almost devoid of BSi, we present evidence for the rapid recycling of bloom derived BSi that generates striking transient peaks in sediment pore water [DSi], which is a feature that is subject to future shifts in phytoplankton community compositions. Using a simple mass balance calculation we show that the pore water DSi pool is supplemented by a lithogenic Si source (LSi), while our sediment pore water Si isotopic profiles also uncover a coupling of the iron (Fe) and Si cycles. This has previously been observed in lower latitude marine sediment systems and thus provides further support for a redox influence on oceanic pore water DSi. We suggest that a high LSi:BSi ratio and apparent Fe (oxyhydr)oxide influence could lead to a degree of stability in the annual background benthic flux of DSi despite the pressures on pelagic phytoplankton communities. Coupled with supporting isotopic evidence for the precipitation of authigenic clays in Barents Sea sediment cores, our observations have implications for the sink vs recycling terms in the regional Si budget.

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