Relative efficiencies of different filters in retaining phytoplankton for pigment and productivity studies

Nayar, Sasi; Chou, L. M.

doi:10.1016/s0272-7714(03)00075-1

Cited by 55 publications

(39 citation statements)

References 26 publications

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“…In our view, these differences likely reflect filtering artifacts resulting from cell lysis, the incomplete retention of cells by GF/F filters, or both. Inefficient retention of cells or chlorophyll by GF/F filters (at times exceeding 50%) has been observed (Dickson and Wheeler 1993;Knefelkamp et al 2007;Nayar and Chou 2003;Stockner et al 1990;Taguchi and Laws 1988), although other studies report few, if any, problems (Chavez et al 1995). This discrepancy may be due to filter brand or differential treatment (e.g., precombustion temperature or duration) or filtration volume impacting the effective pore size.…”

Section: Discussionmentioning

confidence: 99%

The measurement of phytoplankton biomass using flow‐cytometric sorting and elemental analysis of carbon

Graff

Milligan

Behrenfeld

2012

Limnology & Ocean Methods

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Phytoplankton are one of a multitude of particle types in the marine environment that contribute to the particulate organic carbon pool. Current methods for estimating phytoplankton carbon (C phyto ) in the field rely on proxy measurements, such as chlorophyll or cell biovolume conversions. Other means of estimating C phyto include remote-sensing applications that convert optical properties, such as chlorophyll fluorescence or particulate backscattering, into biomass. These values, however, are not well constrained due to the variability of phytoplankton physiology (i.e., internal pigment concentrations) and the lack of field data for validating C phyto retrievals. Here we introduce a method that uses flow cytometry to isolate phytoplankton from the total particle field. Phytoplankton samples are then analyzed for total carbon content. Analyses of laboratory cultures of Synechococcus, Micromonas pusilla, and Thalassiosira pseudonana indicate that this method allows elemental analysis of phytoplankton cells in the absence of unwanted particles. Tests of field samples show that the structure of the natural community is retained in a sorted sample. The acquisition of C phyto data using this method will 1) benefit remote-sensing applications by allowing more thorough validation of phytoplankton carbon estimates from space, 2) improve our knowledge of phytoplankton stoichiometry, and 3) provide a better understanding of phytoplankton physiological responses to environmental forces.

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Section: Discussionmentioning

confidence: 99%

The measurement of phytoplankton biomass using flow‐cytometric sorting and elemental analysis of carbon

Graff

Milligan

Behrenfeld

2012

Limnology & Ocean Methods

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“…Subsequently melt-water salinity was measured (ice core salinity) and subsamples were filtered through previously combusted (400°C for 4 h) GF/F filters before freezing at −20°C. The effective pore size of GF/F filters decreases to 0.2 μm with the precombustion process reducing the particle cutoff size to 0.2 μm, thus making filters suitable for measurement of dissolved parameters (51,52).…”

Section: Methodsmentioning

confidence: 99%

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Underwood

Aslam

Michel

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions. S ea ice covers extensive regions of the Arctic and SouthernOceans, as well as some subpolar seas, and exhibits major annual, interannual, and long-term climate-related variability in age, thickness, and structure (1-3). Sea ice is not an inert physical barrier to air-ocean exchange (4), and both microbial activity and physico-chemical reactions within the ice contribute to regional-scale biogeochemical processes at the air-ocean surface interface (5).Sea ice provides a range of habitats for diverse biological assemblages that are characterized by high standing stocks of microalgae and bacteria (6). These microorganisms produce large quantities of dissolved organic carbon (DOC), often in the form of carbohydrate-rich extracellular polymeric substances (EPS) (7). Microbial EPS exist in a dynamic equilibrium from dissolved polysaccharides (dEPS <0.2 μm) to complex particulate EPS that can form gels on the millimeter to centimeter scale (8). Here we focus on the biologically relevant dissolved carbohydrates (dCHO) that constitute a substantial fraction of the DOC in sea ice (9-13) (Fig. 1). dCHO are concentrated from sea ice DOC by dialysis (>8 kDa), with subsequent treatment allowing the definition of four subcomponents of the total dCHO pool: (i) dissolved uronic acids (dUA), produced by ice diatoms and ice bacteria (14-16), that confer strong cross-linkages between polymer chains (8), forming low solubility EPS complexes w...

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“…For analysis of properties of DOM, a portion of sample water was filtered through pre-combusted (450 • C for 4 h) 0.7 µm GF/F (Whatman). The nominal pore size of GF/F filters decreases with the pre-combustion process reducing the particle cutoff size, thus making the selected filter more suitable for measurement of dissolved parameters (Nayar and Chou 2003;Hulatt and Thomas 2010). A subset of these GF/F filtered samples for colored dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM) were stored in acid-washed (10 % HCl) and pre-combusted glass vials at 4 • C until absorbance and fluorescence measurements were made within two weeks from sampling.…”

Section: Experimental Designmentioning

confidence: 99%

Bioavailability of riverine dissolved organic matter in three Baltic Sea estuaries and the effect of catchment land use

et al. 2013

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Abstract. The microbial degradation of dissolved organic carbon and nitrogen (DOC, DON) was studied in three Finnish boreal estuaries with contrasting land use patterns (Kiiminkijoki -natural forest and peatland; Kyrönjoki -agricultural; Karjaanjoki -mixed/urban). Bioassays of 12-18 d long durations were used in 3 seasons at in situ temperatures. Besides the bulk parameters, a suite of dissolved organic matter (DOM) quality parameters were also investigated, including colored DOM (CDOM), fluorescent DOM and the molecular weight of DOM. Bioavailable DOC and DON pools varied significantly between the estuaries, from 7.9 to 10.6 % and from 5.5 to 21.9 %, respectively. DOM originating from the catchment dominated by natural forests and peatlands (Kiiminkijoki) had the lowest DOC and DON degradation rates, as well as the lowest proportions of biodegradable DOC and DON. A greater proportion of agricultural land in the catchment increased the bioavailability of DON, but not the bioavailability of DOC (Kyrönjoki). Additionally, DOM quality varied significantly between the estuaries, and DOM originating from the agricultural Kyrönjoki catchment sustained higher DOC and DON degradation rates and higher bacterial growth efficiency (BGE) compared to those of the natural forest and peat dominated Kiiminkijoki catchment. The quality of DOM, indicated by differences in CDOM, fluorescent DOM and molecular weight, varied between estuaries with differing land use and was concluded to be major driver of BGE of these systems and thereafter to the microbial CO 2 fluxes from the estuaries. The differences in BGE resulted in a 5-fold difference in the calculated daily bacterial CO 2 emissions between the study's estuaries due to bacterial activity, ranging from 40 kg C d −1 in the Karjaanjoki estuary to 200 kg C d −1 in the Kyrönjoki estuary. Lower DOC : DON ratios, smaller molecular weight and higher CDOM absorption spectral slope values of DOM resulted in higher proportion of the initial DOC and DON being transferred to microbial growth and therefore to the pelagic food web. The pristine, peatland and forest-dominated Kiiminkijoki catchment had the lowest BGE, and therefore proportionally highest CO 2 fluxes.

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Relative efficiencies of different filters in retaining phytoplankton for pigment and productivity studies

Cited by 55 publications

References 26 publications

The measurement of phytoplankton biomass using flow‐cytometric sorting and elemental analysis of carbon

The measurement of phytoplankton biomass using flow‐cytometric sorting and elemental analysis of carbon

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

Bioavailability of riverine dissolved organic matter in three Baltic Sea estuaries and the effect of catchment land use

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