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  • 1
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    Is there a decline in marine phytoplankton? (2011)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2011-04-15
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McQuatters-Gollop, Abigail -- Reid, Philip C -- Edwards, Martin -- Burkill, Peter H -- Castellani, Claudia -- Batten, Sonia -- Gieskes, Winfried -- Beare, Doug -- Bidigare, Robert R -- Head, Erica -- Johnson, Rod -- Kahru, Mati -- Koslow, J Anthony -- Pena, Angelica -- England -- Nature. 2011 Apr 14;472(7342):E6-7; discussion E8-9. doi: 10.1038/nature09950.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK. abiqua@sahfos.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21490625" target="_blank"〉PubMed〈/a〉
    Keywords: Aquatic Organisms/growth & development/*isolation & purification/metabolism ; Atlantic Ocean ; Bias (Epidemiology) ; Biomass ; Chlorophyll/analysis ; Data Collection/methods ; *Ecosystem ; Fisheries ; Phytoplankton/growth & development/*isolation & purification/metabolism ; Reproducibility of Results ; Seawater/chemistry/microbiology ; Time Factors
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of enclosure in large plastic bags on diurnal change in oxygen concentration in tropical ocean water (1982)
    Springer
    Marine biology 70 (1982), S. 99-104 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From November 1980 to February 1981 the concentration of oxygen dissolved in the surface mixed layer of the oligotrophic Caribbean Sea off Curaçao was quite constant (420.77±1.98 μg at l-1). However, immediately following enclosure in 4500-1 plastic bags reaching to a depth of 5 m the oxygen concentration began to decrease, down to values below saturation (405 μg at l-1) within 48 h. Autotrophic and heterotrophic nanoplankton cell numbers and algal pigments in bags remained constant or increased slightly during the first 24 h of enclosure. The rate of decrease in oxygen concentration in bags was significantly higher during daylight hours than in the night, which suggests that photo-oxidative processes were involved in the additional daytime loss of oxygen. The dramatic “enclosure effect” on the oxygen content of the water in the bags can be taken as evidence of the dependence of the oxygen concentration near the tropical ocean's surface on supply from below: in water freely circulating in the euphotic zone deviations from the mean oxygen concentration during a diurnal cycle were 0.47% at most, differential losses near the surface being counteracted through vertical exchange; while in water separated from the rest of the mixed layer in the plastic bags losses due to respiration of the enclosed plankton community plus an even greater loss, assigned to non-biological, photosensitized oxidation processes, were up to 10 μg at O2 l-1 in 24 h. Although photo-oxidation is confined to the very surface the oxygen flux involved may be important enough to necessitate consideration of a photochemically induced loss factor in oxygen budget calculations, e.g. when primary production is to be estimated from diurnal oxygen curves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397300
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  • 3
    Electronic Resource
    Electronic Resource
    Dominance of Cryptophyceae during the phytoplankton spring bloom in the central North Sea detected by HPLC analysis of pigments (1983)
    Springer
    Marine biology 75 (1983), S. 179-185 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microscopic observations of Lugol-preserved samples collected near a subsurface drogue during the spring bloom of 1981 in the central North Sea suggested that the phytoplankton crop consisted mainly of diatoms. However, the relative abundance of alloxanthin among the carotenoids measured by reversed-phase, high-performance liquid chromatography indicated that in most samples Cryptophyceae were at least as abundant. On the basis of a multiple regression analysis of pigment concentrations to obtain pigment ratios, the contribution of Cryptophycean chlorophyll to total chlorophyll was calculated. The Cryptophyceae:diatom ratio appeared to be variable during the period of observations, ranging between 0 at the beginning to 1.0 ten days later. It is recommended that the classical method of counting phytoplankton for crop estimates be supplemented by chemotaxonomical studies with modern quantitative chromatographic methods such as HPLC for the measurement of algal pigments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406000
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  • 4
    Electronic Resource
    Electronic Resource
    Floristic and physiological differences between the shallow and the deep nanophytoplankton community in the euphotic zone of the open tropical Atlantic revealed by HPLC analysis of pigments (1986)
    Springer
    Marine biology 91 (1986), S. 567-576 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Suspended matter sampled in 1982 in the North Equatorial Current, in the open Atlantic to the west of West Africa, was analyzed by high performance liquid chromatography. The pigment fingerprint of samples taken in the surface mixed layer was dominated by zeaxanthin and chlorophyll a, in agreement with observed dominance of coccoid cyanobacteria. Near the bottom of the euphotic zone the fingerprint was more complicated, with a sharp transition at the depth of the deep chlorophyll maximum layer to dominance of chlorophyll b, 19′-hexanoyloxyfucoxanthin and an unknown fucoxanthin derivative in the lower part of this layer; this fingerprint suggests dominance of eukaryotes (green algae, Prymnesiophyceae and Chrysophyceae) at depth. Up to 90% of the chl a was contained in particles smaller than 8 μm, and in the surface mixed layer even more than 50% in particles smaller than 1 μm. The high concentration of zeaxanthin relative to chl a near the surface suggests adaptation of the cyanobacteria to exposure to high irradiance. Evidence of this adaptation was the very high specific phytoplankton growth rate between sunrise and sunset (μ=0.16 h-1), measured by recording 14C incorporation into organic carbon and into chl a carbon after isolation of the latter by HPLC. The high concentration of chl b relative to chl a at depth was possibly caused by shade-adapted green algae containing more chl b than chl a. The specific growth rate of the deep “shade” community was low (μ〈0.04 h-1), yet net primary production, calculated on the basis of chl a increase during incubation, was greatest at depth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392609
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of phytoplankton pigments by HPLC before, during and after mass occurrence of the microflagellate Corymbellus aureus during the spring bloom in the open northern North Sea in 1983 (1986)
    Springer
    Marine biology 92 (1986), S. 45-52 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Daily observations in April and May 1983 near a subsurface drifter launched in the Fladen Grounds area of the North Sea revealed that a large crop of the microflagellate Corymbellus aureus Green, producing up to 3 g C m-2 d-1, succeeded the diatoms dominating during the earlier phase of the spring bloom. The concentration of fucoxanthin was highest during the first half of May, while pigment fingerprints of high-performance liquid chromatograms of suspended matter sampled during the second half of May were dominated by 19′-hexanoyloxyfucoxanthin, the main carotenoid of C. aureus (0.8x10-9 mg cell-1). This colonial Prymnesiophycean was described for the first time less than 10 years ago and has nerver been reported to be present in the North Sea. After 16 May the C. aureus population rapidly lost its growth potential, but the peak of the bloom in terms of cell number was found several days later (up to 9x106 cells per dm3 on 19 May). The population then started to decline; senescence was associated with decreasing pigment contents of cells. The low growth rate of copepods registered during the second half of May was probably related to the poor quality of C. aureus as copepod food: the concentration of a phaeophorbide a typically found in copepod fecal pellets was highest during the diatom phase of the spring bloom preceding the C. aureus bloom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392744
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of physical and biological processes on the concentration of O2 and CO2 in the ice-covered Weddell Sea in the Spring of 1988 (1992)
    Springer
    Polar biology 12 (1992), S. 163-170 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In October and November 1988, measurements of oxygen and total dissolved inorganic carbon (TCO2) concentrations were made in the northwestern Weddell Sea to the south and north of the marginal ice edge, in order to estimate the relative importance, regarding their variations, of both biological (photosynthesis and respiration) and physical (transport of O2 and CO2 by turbulent movements and by intrusion from the atmosphere) processes. In the ice-covered region, both respiration and upwelling determined the O2 and TCO2 variations, whilst in the open water just north of the marginal ice edge, photosynthetic activity was the most important factor controlling O2 and TCO2 levels. These findings underline the importance of the activity of the pelagic ecosystem in determining the concentration of O2 and CO2 not only in the ice-free but also in the ice-covered Antarctic Ocean.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238256
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  • 7
    Electronic Resource
    Electronic Resource
    Abundance of cryptophyceae and chlorophyll b-containing organisms in the Weddell-Scotia Confluence area in the spring of 1988 (1992)
    Springer
    Polar biology 12 (1992), S. 43-52 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary During a cruise in the Weddell-Scotia Confluence area (EPOS Leg 2: November–January 1988/1989) nanophytoplankton composition was determined by employing taxon-specific pigment measurements with HPLC. The biomass of the most important components was estimated by using specific pigment ratios measured in cultures of two cryptomonads and a prasinophyte. Highest cryptophyte biomass was found along the retreating ice-edge; the contribution of cryptophytes to total phytoplankton crop increased with time, reaching monospecific bloom conditions at the end of the cruise. Chlorophyll b-containing organisms and Prymnesiophyceae were present everywhere and dominated in the ice-covered part of the survey area. Cryptophyte-specific pigment measurements were in reasonable agreement with cryptophyte cell numbers. Prasinophyte cell counts, however, did not match with measured chlorophyll b concentrations. The quantitative importance of the nanophytoplankton groups reported here underlines the diversity of the plankton in the Southern Ocean's marginal ice zone system which may have implications for food chain dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239964
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  • 8
    Electronic Resource
    Electronic Resource
    The impact of phytoplankton on spectral water transparency in the Southern Ocean: implications for primary productivity (1994)
    Springer
    Polar biology 14 (1994), S. 127-136 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spectral water transparency in the Northern Weddell Sea was studied during Austral spring. The depth of the 1-% surface irradiance level (“euphotic depth”) varied between 35 and 109 m and was strongly influenced by phytoplankton biomass. Secchi depths were non-linearly related to euphotic depth. In phytoplankton-poor water, the most penetrating spectral region was restricted to a relatively narrow waveband in the blue (∼488 nm), but the range was broader, between 488 and 525 nm when phytoplankton were abundant. Water transparency in the red spectral range was always low and only to a small extent affected by phytoplankton. Two independent procedures were used to quantify the impact of phytoplankton on spectral water transparency: (1) Regression analysis of spectral in situ vertical light attenuation coefficients in the sea, against coincident chlorophyll concentrations. This method gave chlorophyll-specific light attenuation coefficients; the y-intercept could be interpreted as a measure of light attenuation by pure water plus non-algal material. (2) Spectra of in vivo light absorption derived by spectroscopy, using phytoplankton enriched to varying degrees onto filters. Thus chlorophyll-specific absorption cross-sections were determined. Estimates obtained by both procedures were in close agreement. By integrating over the spectrum of underwater irradiance, in situ chlorophyll-specific absorption cross sections of phytoplankton suspensions, related to all photosynthetically active radiation, were calculated. Light absorption by phytoplankton for photosynthesis is accomplished mainly in the blue spectral range. Also dissolved and particulate organic matter contributed to the attenuation of blue light. Because in water poor in phytoplankton, underwater irradiance was progressively restricted to blue light, chlorophyll-specific absorption cross-sections of phytoplankton, averaged over the spectrum of photosynthetically active irradiance, increased with water depth. In water with elevated phytoplankton biomass, overall light attenuation was generally enhanced. However, because the spectral composition of underwater light changed relatively little with depth, except immediately below the water surface, light absorption cross-sections of phytoplankton changed little below 10 m depth. Vertical differences in the proportions of underwater light absorbed by the phytoplankton community here were mainly dependent on biomass variations. Because of the comparatively small attenuation of blue light by non-algal matter, the efficiency of light harvesting by phytoplankton at any given concentration of chlorophyll in Antractic waters is greater than in other marine regions. At the highest phytoplankton biomass observed by us, as much as 70% of underwater light was available for phytoplankton photosynthesis. When phytoplankton were scarce, 〈10% of underwater light was harvested by phytoplankton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234975
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  • 9
    Electronic Resource
    Electronic Resource
    Removal of “Podon” polyphemoides from the genus podon (1971)
    Springer
    Hydrobiologia 38 (1971), S. 61-66 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resumen Se argumenta que Podon polyphemoides no debe colocarse más en el genero Podon, ya que solamente tiene similitud con las otras especies de este género en la configuración del cuerpo, una caracteristica de menor importancia en la distinción del Orden Polyphemoidea. Se propone el nombre nuevo Pleopis polyphemoides.
    Notes: Summary It is argued that Podon polyphemoides does not belong in the genus Podon, since the only similarity with the other species in this genus is the body outline, a characteristic of minor importance in generic distinction in the Polyphemoidea. The new name Pleopis polyphemoides is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00036793
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  • 10
    Electronic Resource
    Electronic Resource
    Degradation of diatom chlorophyll to colourless, non-fluorescing compounds during copepoo grazing (1991)
    Springer
    Aquatic ecology 25 (1991), S. 65-72 
    Details
    ISSN: 1573-5125
    Keywords: copepod grazing ; chlorophyll degradation ; carotenoid enrichment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During grazing of the copepodTemora longicornis onThalassiosira eccentrica phaeophorbide-a and several phaeophytins-a appeared in the culture vessels. However, a variable portion of the diatom's chlorophyll-a was degraded to substances that could not be detected either spectrophotometrically or fluorometrically. Chlorophyll-c and fucoxanthin were also lost during diatom cell transit throughTemora's gut. The variability between experiments in the destruction of chl.a to colourless residues is ascribed to differences in coprophagy and in transit time through the copepod gut, processes related to filtering rate and the ambient food concentration. Because the pigment loss is variable, grazing pressure cannot be estimated by simply recording bulk phaeopigment concentrations. The net result of the appearance of a fucoxanthinol-like pigment while all other pigments disappeared is a gradual carotenoid enrichment of the samples during grazing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259591
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