Light Utilization Efficiency in Natural Phytoplankton Communities

Dubinsky, Zvy

doi:10.1007/978-1-4684-3890-1_5

Cited by 60 publications

(38 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, photosynthetically available light transmission conditions were determined down to the chemocline in steps of 0.1 m using two LI-193SA spherical quantum sensors and a LI-COR 1000 data logger (LI-COR Ltd., Lincoln, NE). These measurements were used to calculate vertical attenuation coefficients (Kd) of photosynthetically available radiation (8) for the mixolimnion and the bacterial layer. The YSI 6000 profiler and LI-COR sensors were fixed at the lowest part of a thin-layer pneumatic multisyringe sampler (3,4,31,32), which was used to take 20 simultaneous samples of 100 ml over a total depth of 2 m.…”

Section: Methodsmentioning

confidence: 99%

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland

Tonolla

Peduzzi

Hahn

2005

Appl Environ Microbiol

View full text Add to dashboard Cite

Population analyses in water samples obtained from the chemocline of crenogenic, meromictic Lake Cadagno, Switzerland, in October for the years 1994 to 2003 were studied using in situ hybridization with specific probes. During this 10-year period, large shifts in abundance between purple and green sulfur bacteria and among different populations were obtained. Purple sulfur bacteria were the numerically most prominent phototrophic sulfur bacteria in samples obtained from 1994 to 2001, when they represented between 70 and 95% of the phototrophic sulfur bacteria. All populations of purple sulfur bacteria showed large fluctuations in time with populations belonging to the genus Lamprocystis being numerically much more important than those of the genera Chromatium and Thiocystis. Green sulfur bacteria were initially represented by Chlorobium phaeobacteroides but were replaced by Chlorobium clathratiforme by the end of the study. C. clathratiforme was the only green sulfur bacterium detected during the last 2 years of the analysis, when a shift in dominance from purple sulfur bacteria to green sulfur bacteria was observed in the chemocline. At this time, numbers of purple sulfur bacteria had decreased and those of green sulfur bacteria increased by about 1 order of magnitude and C. clathratiforme represented about 95% of the phototrophic sulfur bacteria. This major change in community structure in the chemocline was accompanied by changes in profiles of turbidity and photosynthetically available radiation, as well as for sulfide concentrations and light intensity. Overall, these findings suggest that a disruption of the chemocline in 2000 may have altered environmental niches and populations in subsequent years.Lake Cadagno is a crenogenic meromictic lake located in the catchment area of a dolomite vein rich in gypsum in the Piora valley in the southern Alps of Switzerland (46°33ЈN, 8°43ЈE). This lake is characterized by a compact chemocline with high concentrations of sulfate; steep gradients of oxygen, sulfide, and light; and a turbidity maximum that correlates to large numbers of bacteria (up to 10 7 cells ml Ϫ1 ) (5, 21, 31). Molecular methods such as 16S rRNA gene clone library analysis and subsequent in situ hybridization with specific fluorescent probes identified the most abundant bacteria in the chemocline as large-and small-celled purple sulfur bacteria. These accounted for up to 35% of all bacteria (34) and consisted of Chromatium okenii as the only representative of the largecelled purple sulfur bacteria and of four populations related to the genus Lamprocystis that represented the small-celled purple sulfur bacteria (31). Small-celled purple sulfur bacteria were most abundant with two populations accounting for 40 to 80% of the purple sulfur bacteria depending on the season (31). These populations, designated D and F, were not represented by a cultured relative, whereas the remaining populations were identified as Lamprocystis purpurea and Lamprocystis roseopersicina. L. purpurea and L. roseopersicina wer...

show abstract

Section: Methodsmentioning

confidence: 99%

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland

Tonolla

Peduzzi

Hahn

2005

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Hence it is expected that photoadaptation is an important feature of phytoplankton physiology. Photosynthetic quantum yields of phytoplankton in natural waters have frequently been determined to indicate cellular responses to ambient light conditions (see [5] for a discussion). It is important in such studies to know the absorption and photosynthesis action spectra of the algal populations to understand how efficiently they are able to use the total ambient light.…”

Section: Abstracirmentioning

confidence: 99%

Photoadaptation in Marine Phytoplankton

Neori¹,

Holm‐Hansen²,

Mitchell³

et al. 1984

Plant Physiol.

View full text Add to dashboard Cite

ABSTRACIrThe optical properties of marine phytoplankton were examined by measuring the absorption spectra and fluorescence excitation spectra of chlorophyll a for natural marine parties collected on glass fiber filters. Samples were collected at different depths from stations in temperate waters of the Southern California Bight and in polar waters of the Scotia and Ross Seas. At all stations, phytoplankton fluorescence excitation and absorption spectra changed systematically with depth and vertical stability of the water columns. In samples from deeper waters, both absorption and chlorophyll a fluorescence excitation spectra showed enhment in the blue-to-green portion of the spectrum (470-560 -m) Light is often a limiting factor for the growth of marine phytoplankton. Hence it is expected that photoadaptation is an important feature of phytoplankton physiology. Photosynthetic quantum yields of phytoplankton in natural waters have frequently been determined to indicate cellular responses to ambient light conditions (see [5] for a discussion). It is important in such studies to know the absorption and photosynthesis action spectra of the algal populations to understand how efficiently they are able to use the total ambient light. This is of particular concern at depths where light intensity limits phytoplankton growth.The light environment in the water to which the algae have to ' Supported in part by grants to D. A. K. from the National Environmental Satellite Service (04-7-158-44123) adapt is relatively simple: intensity decreases with depth and is associated with modifications to the light spectrum. The spectral distribution of irradiance shows a broad blue-green maximum below the surface. With increasing depth, the peak narrows and shifts slowly toward blue in clear ocean water (12). As the concentrations of phytoplankton pigments in the water increase, their high violet and blue absorption diminishes the light in that region ofthe spectrum and shifts the maximal irradiance toward the green region (1). This was a basic environmental justification for the Engelmann theory of complementary chromatic adaptation (4,15,24). Field studies have shown that phytoplankton at depth have decreased maximal rates of photosynthesis (25) and increased cellular concentrations of Chl a (2, 13). These two features yield dramatic decreases in assimilation number with depth (8,25). Recent studies of algal cultures indicate that adaptation to low light involves increases in the cellular concentration of PSI reaction centers (20,21) and PSII reaction centers (9), as well as the size of the photosynthetic unit (8, 20). Low light-adapted cells show an increased ratio of accessory pigments to Chl a as well as relative enhancement ofthe green and blue regions in the spectra of absorption, Chl a fluorescence excitation, and oxygen evolution (15,17,22,26).Studies of photoadaptation processes in natural aquatic environments have been limited mainly to measurements of the photosynthetic response of the phytoplankton to differing light ...

show abstract

“…) is the photosynthetic radiation usable by phytoplankton, and it was estimated according to Dubinsky (1980): (4) where a ph (z,λ) is the phytoplankton spectral absorption coefficient, and E(z,λ) is the spectral irradiance at each depth determined from combining underwater measurements taken with a Li-1800UW spectroradiometer and incident irradiance at the sea surface measured on deck at 1 min intervals with a LI-190SA sensor. A 24 h average EPUR(z) was considered to remove from PP estimates the short time variability caused by clouds.…”

Section: Methodsmentioning

confidence: 99%

Dissolved and suspended organic carbon in the Atlantic sector of the Southern Ocean. Stock dynamics in upper ocean waters

Doval¹,

Álvarez‐Salgado²,

Gasol³

et al. 2001

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Dissolved and suspended organic carbon (DOC and POC) distributions were studied in the undersampled Atlantic sector of the Southern Ocean during Cruise HE052 of the 'Bio Hespérides' in December 1998. The coastal waters of the ice edge, the Gerlache Strait, and the open-ocean waters of the Weddell Sea and the Drake Passage were sampled. The high correlation between chlorophyll a (chl a), DOC and POC suggest that a considerable fraction (estimated at 15 to 30%) of the organic matter available in the upper mixed layer of the different study regions is the product of synthesis and early degradation of planktonic primary production. Relatively low renewal times (≤ 2 wk) of this material, except in the Polar Front Zone (> 5 wk), were deduced from measured primary/bacterial production rates. Maximum contributions of this potentially bioreactive organic carbon pool (TOC B ) to the total organic carbon (TOC) were observed in the highly productive waters of the ice edge (24%) and Gerlache Strait (30%) regions, where high chl a levels and shallow upper mixed layers (due to marked salinity gradients) occurred. DOC represented 42 and 56% of TOC B , in these regions, respectively. In contrast, TOC B comprised ≤ 20% of TOC in the less productive open-ocean waters of the Weddell Sea and Drake Passage, where DOC made up ≥ 65% of TOC B . The Subantarctic Zone constituted an exception, with high chl a levels and a shallow upper mixed layer (due to marked temperature gradients): 29% of the organic carbon in the upper mixed layer was TOC B , 68% of which was in the dissolved fraction. Accumulation of DOC in the study regions points to a reduction in bacterial activity through mechanisms other than substrate limitation.

show abstract

Light Utilization Efficiency in Natural Phytoplankton Communities

Cited by 60 publications

References 46 publications

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland

Long-Term Population Dynamics of Phototrophic Sulfur Bacteria in the Chemocline of Lake Cadagno, Switzerland

Photoadaptation in Marine Phytoplankton

Dissolved and suspended organic carbon in the Atlantic sector of the Southern Ocean. Stock dynamics in upper ocean waters

Contact Info

Product

Resources

About