Bibliography - M. K. Reuer
- Reuer, M. K., B. Barnett, Michael Bender, P. G. Falkowski, and M. B. Hendricks, 2007: New estimates of Southern Ocean biological production rates from O2/Ar ratios and the triple isotope composition of O2. Deep Sea Research I, 54(6), doi:10.1016/j.dsr.2007.02.007
[ Abstract ]We report O2/Ar ratios (a constraint on net community production) and the triple isotopic composition of dissolved O2
(a constraint on gross primary production) in samples collected from the surface mixed layer on 23 Southern Ocean
transits. Samples were collected at 1–2° meridional resolution during the austral summer. Methodological limitations
notwithstanding, the results constrain the net/gross production ratio, net O2 production, and gross O2 production at
unprecedented resolution throughout the Southern Ocean mixed layer. Gross O2 production rates inferred from the
oxygen triple isotopes are greater than production rates calculated from a model based on remotely sensed chlorophyll.
This result agrees with previous 18O and 14C incubations along 170°W. O2/Ar ratios exceeding saturation are consistently
observed within the Subantarctic and Polar Frontal Zones south of New Zealand and Australia, showing that a net
autotrophic community predominates during austral summer. Lower O2/Ar values are observed within the Drake Passage
and Antarctic Zone, suggesting unresolved influences of low net community production, net heterotrophy, and upwelling
of O2-undersaturated waters. In autotrophic waters of the austral summer mixed layer, ratios of net community
production/gross O2 production scatter about 0.13, corresponding to f ratios of ˜0.25. Net community/gross O2
production ratios show no meridional gradient across the Antarctic Circumpolar Current, suggesting that an
approximately constant fraction of gross primary productivity is regenerated or exported. Our calculated net O2
production rates are in satisfactory agreement with comparable published estimates. Net and gross O2 production rates are
highest in the Subantarctic and decline to the south, paralleling the well-known trend of chlorophyll a concentrations. In
an analysis of variance of net O2 production and gross O2 production with other environmental variables, the strongest
correlations are between net O2 production and sea surface temperature (SST) (direct correlation), climatological [NO3]
(inverse correlation), and estimates of primary productivity derived from a remote sensing (direct correlation). These
trends are as expected if aerosol iron input is the most important influence on production. They are unexpected if
upwelling-derived SiO2 and iron are the leading influence or if lower SSTs promote greater export in this region.
- Kaiser, J., M. K. Reuer, B. Barnett, and Michael Bender, 2005: Marine productivity estimates from continuous oxygen/argon ratio measurements by membrane inlet mass spectrometry. Geophysical Research Letters, 32(L19605), doi:10.1029/2005GL023459
[ Abstract ]Dissolved oxygen/argon (O2/Ar) ratios in the oceanic mixed layer are indicative of
net community production (NCP) because O2 and Ar share similar physical solubility
properties, but only O2 is biologically produced and consumed. We describe a membrane
inlet mass spectrometer (MIMS) that allows continuous high-precision shipboard analysis
of O2/Ar ratios and eventually other gases, calibrated with discrete samples analyzed in
the laboratory. We also present O2/Ar data from the eastern equatorial Pacific. Shortterm
reproducibilities of 0.05% were achieved. Meridional gradients and small-scale
phenomena were clearly resolved. O2/Ar undersaturations around the equator reflect the
interaction of biological and physical forcings. Mixed-layer NCP estimated from wind
speed-gas exchange parameterizations was near zero north of 2.75°N, and about 12 mmol
m-2 d-1 south of 6.75°S. Ar supersaturations, calculated from MIMS O2/Ar measurements
and accompanying O2 concentration measurements, ranged from -0.8 to +3.0%.
Direct link to page: http://cmi.princeton.edu/bibliography/results.php?author=3884
