Effects of polyethylene-type microplastics on the growth and primary production of the freshwater phytoplankton species Scenedesmus armatus and Microcystis aeruginosa

2021 ◽  
pp. 104510
Author(s):  
A. Sánchez-Fortún ◽  
C. Fajardo ◽  
C. Martín ◽  
A. D’ors ◽  
M. Nande ◽  
...  
Keyword(s):  
Primary Production ◽  
Microcystis Aeruginosa ◽  
Phytoplankton Species ◽  
Freshwater Phytoplankton

Extracellular phosphatase activity of freshwater phytoplankton exposed to different in situ phosphorus concentrations

2005 ◽  
Vol 56 (4) ◽  
pp. 417 ◽  
Author(s):  
A. Ŝtrojsová ◽  
J. Vrba ◽  
J. Nedoma ◽  
K. Ŝimek
Keyword(s):  
Enzyme Activity ◽  
Phosphatase Activity ◽  
Microcystis Aeruginosa ◽  
Image Cytometry ◽  
Phosphorus Concentration ◽  
Phytoplankton Species ◽  
Freshwater Phytoplankton ◽  
Fragilaria Crotonensis ◽  
Species Specific

Extracellular phosphatase production and biomass change were investigated in phytoplankton species transplanted from the phosphorus-limited dam area of a eutrophic reservoir and exposed to the phosphorus-sufficient inflow part and vice versa. Extracellular phosphatase activity was studied using the enzyme-labelled fluorescence (ELF) technique, allowing for direct microscopic detection of enzyme activity and, moreover, its quantification using image cytometry. Several phytoplankton species (e.g. Anabaena planctonica, Microcystis aeruginosa, Fragilaria crotonensis, Ankyra ancora and Planktosphaeria gelatinosa) regulated phosphatase activity according to external phosphorus concentration. On the contrary, picocyanobacteria and several green algae (Coelastrum microporum, Crucigeniella sp., Pediastrum tetras, and Staurastrum planctonicum) did not produce extracellular phosphatases at all. The species-specific extracellular phosphatase activity of F. crotonensis, A. ancora, and P. gelatinosa ranged between 0.02 and 3.5 fmol μm−2 h−1.

Primary Production and Phytoplankton in the Experimental Lakes Area, Northwestern Ontario, and other Low-Carbonate Waters, and a Liquid Scintillation Method for Determining 14C Activity in Photosynthesis

1971 ◽  
Vol 28 (2) ◽  
pp. 189-201 ◽  
Author(s):  
D. W. Schindler ◽  
S. K. Holmgren
Keyword(s):  
Primary Production ◽  
Liquid Scintillation ◽  
Species Abundance ◽  
Euphotic Zone ◽  
Phytoplankton Production ◽  
Phytoplankton Species ◽  
Experimental Lakes Area ◽  
Phytoplankton Species Composition ◽  
Northwestern Ontario ◽  
Filtration Error

A modified 14C method is described for measuring phytoplankton production in low-carbonate waters. The procedure includes the use of the Arthur and Rigler (Limnol. Oceanogr. 12: 121–124, 1967) technique for determining filtration error, liquid scintillation counting for determining the radioactivity of membrane filters and stock 14C solutions, and gas chromatography for measuring total CO2.Primary production, chlorophyll a, and total CO2 were measured for two dates in midsummer from each of several lakes in the Experimental Lakes Area (ELA), ranging from 1 to 1000 ha in area and from 2 to 117 m in maximum depth. Phytoplankton species abundance and biomass were determined for the same dates. Production ranged from 0.02 to 2.12 gC/m3∙day and from 0.179 to 1.103 g C/m2∙day. Chlorophyll ranged from 0.4 to 44 mg/m3 and from 5 to 98 mg/m2 in the euphotic zone. The corresponding ranges for live phytoplankton biomass were 120–5400 mg/m3 and 2100–13,400 mg/m2. Chrysophyceae dominated the phytoplankton of most of the lakes.A system for classifying the lakes in terms of phytoplankton species composition and production–depth curves is developed.

Demographic responses of selected rotifers (Rotifera) and cladocerans (Cladocera) fed toxic Microcystis aeruginosa (Cyanobacteria)

2020 ◽  
Vol 193 (3) ◽  
pp. 261-274
Author(s):  
Alfredo Pérez-Morales ◽  
S.S.S. Sarma ◽  
S. Nandini ◽  
Cristian Alberto Espinosa-Rodríguez ◽  
Ligia Rivera-De la Parra
Keyword(s):  
Population Growth ◽  
Life Table ◽  
Microcystis Aeruginosa ◽  
Green Algae ◽  
Somatic Growth ◽  
Phytoplankton Species ◽  
Scenedesmus Acutus ◽  
Cladoceran Species ◽  
Toxic Cyanobacteria ◽  
Demographic Responses

Tropical waterbodies contain several species of toxic cyanobacteria including Microcystis, which adversely affect the somatic growth, survival and fecundity of zooplankton. Scenedesmus, one of the most common green algae, is even found in Microcystis -dominated waterbodies. It is, therefore possible that in natural ponds, rotifers and cladocerans feed on mixed phytoplankton species containing algae and cyanobacteria. In this work, we quantified demographic responses of three rotifer species (Brachionus calyciflorus, B. rubens, and Plationus patulus), and three cladoceran species (Simocephalus mixtus, Daphnia cf. mendotae and Moina macrocopa) fed toxic Microcystis aeruginosa only or mixed with Scenedesmus acutus. The highest population growth for both rotifer and cladoceran species was observed when Scenedesmus was offered alone or at 75 % of the diet. Daphnia cf. mendotae and B. rubens were less affected by Microcystis while M. macrocopa and B. calyciflorus were more adversely influenced, which was also corroborated by life table demography. In competition bioassays, D. cf. mendotae was more efficient, alone or in competition, when fed with 50 or 25 % of Microcystis. This work explains the dynamics of the zooplanktonic community against gradual changes in phytoplankton due to the presence of cyanobacteria.

scholarly journals Automatic Detection of Freshwater Phytoplankton Specimens in Conventional Microscopy Images

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6704
Author(s):  
David Rivas-Villar ◽  
José Rouco ◽  
Manuel G. Penedo ◽  
Rafael Carballeira ◽  
Jorge Novo
Keyword(s):  
Continuous Monitoring ◽  
Phytoplankton Species ◽  
Water Safety ◽  
Fusion Algorithm ◽  
Freshwater Phytoplankton ◽  
Image Objects ◽  
Fully Automatic ◽  
Conventional Microscopy ◽  
Classical Computer ◽  
Microscopy Images

Water safety and quality can be compromised by the proliferation of toxin-producing phytoplankton species, requiring continuous monitoring of water sources. This analysis involves the identification and counting of these species which requires broad experience and knowledge. The automatization of these tasks is highly desirable as it would release the experts from tedious work, eliminate subjective factors, and improve repeatability. Thus, in this preliminary work, we propose to advance towards an automatic methodology for phytoplankton analysis in digital images of water samples acquired using regular microscopes. In particular, we propose a novel and fully automatic method to detect and segment the existent phytoplankton specimens in these images using classical computer vision algorithms. The proposed method is able to correctly detect sparse colonies as single phytoplankton candidates, thanks to a novel fusion algorithm, and is able to differentiate phytoplankton specimens from other image objects in the microscope samples (like minerals, bubbles or detritus) using a machine learning based approach that exploits texture and colour features. Our preliminary experiments demonstrate that the proposed method provides satisfactory and accurate results.

scholarly journals Primary production during nutrient-induced blooms at elevated CO<sub>2</sub> concentrations

2007 ◽  
Vol 4 (6) ◽  
pp. 4385-4410 ◽  
Author(s):  
J. K. Egge ◽  
T. F. Thingstad ◽  
A. Engel ◽  
R. G. J. Bellerby ◽  
U. Riebesell
Keyword(s):  
Species Composition ◽  
Primary Production ◽  
Experimental Period ◽  
Mineral Nutrient ◽  
Substantial Part ◽  
Phytoplankton Species ◽  
Net Community Production ◽  
Phytoplankton Species Composition ◽  
Alternative Hypotheses

Abstract. Mesocosms experiments (PeECE II and PeECE III) were carried out in 9 transparent mesocosms. Prior to the experimental period, the seawater carbonate system was manipulated to achieve three different levels of CO2. At the onset of the experimental period, nutrients were added to all mesocosms in order to initiate phytoplankton blooms. Rates of primary production were measured by in-situ incubations using 14C-incorporation and oxygen production/consumption. Particulate primary production by 14C was also size fractionated and compared with phytoplankton species composition. Nutrient supply increased the primary production rates, and a net autotrophic phase with 14C-fixation rates up to 4 times higher than initial was observed midway through the 24 days experiment before net community production returned to near-zero and 14C-fixation rates relaxed back to lower than initial. We found a trend in the 14C-based measurements towards higher cumulative primary production at higher pCO2, consistent with recently published results for DIC removal (Riebesell et al., 2007). There where found differences to the size fractionated primary production response to CO2 treatments. The plankton composition changes throughout the bloom, however, resulted in no significant response until the final phase of the experiment where phytoplankton growth became nutrient limited, and phytoplankton community changed from diatom to flagellate dominance. This opens for the two alternative hypotheses that such an effect is associated with mineral nutrient limited growth, and/or with phytoplankton species composition. The lack of a clear net heterotrophic phase in the last part of the experiment supports the idea that a substantial part of production in the upper layer was not degraded locally, but either accumulated there or was exported vertically.

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