Seasonal Periodicity of Diatoms, and Silicon Limitation in Offshore Lake Michigan, 1975

Parker, J. I.; Conway, H. L.; Yaguchi, E.M.

doi:10.1139/f77-087

Cited by 34 publications

(10 citation statements)

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“…Integral production estimates are from in situ and model experiments. euphstic zone assimilation numbers, calculated from integrated production and chlorophyll values, ranged from 6.9 to 14.0 rng E r n g Chl-'*dm' with a mean of 9.7 for the period MayAugust in 1975 (Parker et al 1977). We found similar euphotic zone assimilation numbers for the May-August period, ranging from 5.$ to 16.8 rng C* mg Chl-' ed-' with a mean of 10.0.…”

Section: Lake Michigan Primary Production: Past and Presentsupporting

confidence: 58%

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Dynamics of Lake Michigan Phytoplankton: Primary Production and Growth

Fahnenstiel¹,

Scavia²

1987

Can. J. Fish. Aquat. Sci.

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Primary production was measured with the 14C technique during May through July–August 1982–84. 14C experiments varied from short-term incubations (1–2 h) in a photosynthesis–irradiance (P–I) chamber to 24-h in situ incubations. The maximum assimilation number from six P–I experiments during thermal stratification averaged 2.1 mg C∙mg Chl−1∙h−1 which agreed well with estimates from the 1970s. Chlorophyll-corrected P–I curves were combined with incident irradiation, chlorophyll concentrations, and extinction coefficients to estimate daily production (model estimate). Summer average integral production estimates in 1983 and 1984 were 615–630 mg C∙m−2∙d−1. Approximately 50% of summer primary production occurred below the epilimnion. Daily model production estimates were higher than 24-h in situ estimates at light intensities above Ik, the light saturation parameter, and similar at intensities below Ik. Comparisons of production estimates converted to growth rates suggest that 24-h in situ estimates provide a measure close to net production whereas model estimates provide a measure greater than net production. Summer epilimnetic growth rate estimates were low (range 0.06–0.60∙d−1), reflecting the limited availability of phosphorus.

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Section: Lake Michigan Primary Production: Past and Presentsupporting

confidence: 58%

“…Most Lake Michigan primary production estimates have been based on short-term (2-6 h) "C experiments (see Tarapchak and Stoemer 1976;Parker et al 1977;Moll et al 1984). These estimates were determined from experiments that used a variety of experimental techniques and data reporting methods.…”

Section: Lake Michigan Primary Production: Past and Presentmentioning

confidence: 99%

Dynamics of Lake Michigan Phytoplankton: Primary Production and Growth

Fahnenstiel¹,

Scavia²

1987

Can. J. Fish. Aquat. Sci.

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“…These estimates are low for at least two reasons. High rates of production in the water column were likely missed because the period between February and June was not sampled and rates of production are high in spring (Parker et al 1977;G. L. Fahnenstiel pers.…”

Section: Resultsmentioning

confidence: 99%

Bacterioplankton in Lake Michigan: Dynamics, controls, and significance to carbon flux1

Scavia

Laird

1987

Limnology & Oceanography

178

119

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Lake Michigan bacterial production, based on [3H-methyl]thymidine (TdR) incorporation and empirically determined conversion factors (5-25 x lo9 cells nmol-I), decreased with distance from shore (-2 x over 30 km), was higher at night (1.4 x -2.2 x), and decreased with depth (w 10 x over 100 m). TdR-based growth rates were consistent with independent antibiotic-and dilution-based estimates. Population size varied little and appeared controlled by balanced growth (0.02-0.33 h-l) and grazing (0.039-o. 12 h-l). Growth correlated with temperature only below 10°C. Cell size ranged from 0.015 to 0.072 pm3. Carbon content averaged 0.154 + 0.047 pg C pm-3. Net annual carbon production was 142 g C m-2 yr-l. Summer averages were 28.9 (epilimnion), 10.4 (lo-35 m), 1.6 (hypolimnion) pg C liter' d-*, and 652 mg C m-2 d-' for the water column. Flux to microconsumers averaged 8.4 pg C liter-I d-r in the summer epilimnion.Annual areal bacterial carbon demand is met by autotrophic production only if little of the latter is lost by other means. This suggests that external loads are needed, our conversion factors are high, or autotrophic production is underestimated. Although only small adjustments of those factors will satisfy the annual balance, the summer imbalance is still too large. We suggest that temporal and spatial disequilibrium of labile organic carbon supply and bacterial use is responsible for the apparent discrepancy during summer.

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“…As the diatoms died and were removed from the water column or surface sediments, the silica was recycled, leading to few remains in the sediment. Extensive dissolution and silica recycling has been observed in more productive temperate systems (e.g., Parker et al 1977aParker et al , 1977bNriagu 1978;Conley et al 1988;Ryves et al 2013) and in Alaska (Cornwall and Banahan 1992). The increased terrestrial vegetation production, along with the continual presence of permafrost, may have reduced input of silica to the lake.…”

Section: Diatom-free Zones In Arctic Lake Sedimentsmentioning

confidence: 99%

Interactions between climate and landscape drive Holocene ecological change in a High Arctic lake on Somerset Island, Nunavut, Canada

2017

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This study presents a diatom-based analysis of the post-glacial Holocene environmental history at Lake RS29 on Somerset Island in the Canadian High Arctic. Earliest post-glacial diatom assemblages (10 200-10 000 cal yr BP) consisted mainly of small, benthic fragilarioid taxa. Poor diatom preservation in the early Holocene (~10 000-6200 cal yr BP) is associated with warm conditions, as determined by pollen data from the same core and other paleoclimate estimates from the region. Analysis of this and other sites from across the Canadian Arctic suggest that zones of poor diatom preservation or diatom absence in lake sediment records may be associated with warm conditions. After 6200 cal yr BP, acidophilic assemblages consisting of Aulacoseira spp. and a suite of periphytic taxa indicate acidification since the mid-Holocene. During this time period, cooling causing changes in lake ice phenology was likely a major driver of the reconstructed mid-Holocene pH decline. Watershed processes, including reduced fluxes of base cations as the rate of sediment accumulation slowed, may also be contributors to long-term shifts in lake water pH and associated changes in diatom assemblages. The uppermost sediments in the Lake RS29 record were characterized by abrupt declines in Aulacoseira alpigena and increases in benthic diatom taxa Cyclotella sensu lato, suggesting an increase in lake water pH and longer ice-free seasons.Key words: paleoclimate, Holocene, Canadian Arctic Archipelago, lake sediments, diatoms, paleolimnology, pollen, diatom dissolution.Résumé : Cette étude présente une analyse basée sur les diatomées afin d'examiner l'histoire environnementale de l'Holocène postglaciaire au lac RS29 sur l'île Somerset dans le Haut-Arctique canadien. Les tout premiers assemblages de diatomées postglaciaires (10 200 -10 000 ans BP) étaient constitués principalement de petits taxons benthiques fragilarioid. La pauvre conservation des diatomées au cours de l'Holocène précoce (~10 000-6 200 ans BP) est associée aux conditions chaudes, comme déterminées par les données de pollen provenant de la même carotte et d'autres évaluations paléoclimatiques de la région. L'analyse de ce site et d'autres sites à travers l'Arctique canadien suggère que les zones de pauvre conservation de diatomées ou d'absence de diatomées dans les données de sédiments lacustres enregistrées pourraient être associées aux conditions chaudes. Après 6 200 ans BP, les assemblages d'acidiphiles constitués d'Aulacoseira spp. et d'une gamme de taxons periphytiques indiquent l'acidification depuis l'Holocène moyen. Pendant cette période, le refroidissement causant des changements phénologiques de la glace lacustre était probablement un facteur du milieu important causant la baisse du pH reconstruit de l'Holocène moyen. Les processus des bassins hydrographiques, y compris les flux réduits de cations basiques alors que le taux d'accumulation de sédiments a ralenti, peuvent aussi être des facteurs

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Seasonal Periodicity of Diatoms, and Silicon Limitation in Offshore Lake Michigan, 1975

Cited by 34 publications

References 0 publications

Dynamics of Lake Michigan Phytoplankton: Primary Production and Growth

Dynamics of Lake Michigan Phytoplankton: Primary Production and Growth

Bacterioplankton in Lake Michigan: Dynamics, controls, and significance to carbon flux1

Interactions between climate and landscape drive Holocene ecological change in a High Arctic lake on Somerset Island, Nunavut, Canada

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