Growth rates and elemental composition of Alexandrium monilatum, a red-tide dinoflagellate

Harmful Algae ◽  
2005 ◽  
Vol 4 (2) ◽  
pp. 287-295 ◽  
Author(s):  
Andrew R. Juhl
Keyword(s):  
Elemental Composition ◽  
Growth Rates ◽  
Red Tide ◽  
Alexandrium Monilatum

scholarly journals Ontogenetic changes in the elemental composition and stoichiometry of marine copepods with different life history strategies

2020 ◽  
Vol 42 (3) ◽  
pp. 320-333 ◽  
Author(s):  
Enric Saiz ◽  
Kaiene Griffell ◽  
Albert Calbet
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Elemental Composition ◽  
Growth Rates ◽  
Stoichiometric Composition ◽  
Maximum Growth ◽  
Life History Strategies ◽  
Ontogenetic Variation ◽  
Ontogenetic Changes ◽  
P Content

Abstract We describe the ontogenetic variation in elemental and stoichiometric composition of two copepod species with very contrasted life history patterns, the calanoid Paracartia grani and the cyclopoid Oithona davisae. The first species is a broadcasting, highly productive copepod, whereas the latter is an egg-carrying copepod, much less productive. We reared cultures of both species under conditions of excess food and analyzed their C, N and P composition, and their molar ratios, along development. Both species differed on their specific P content, whereas the specific C and N content were similar. As expected, the specific P content of P. grani was higher, resulting in lower C:P and N:P ratios. Furthermore, we compared our elemental composition data with previously reported stage-specific (nauplii and adult female) maximum growth rates of these two species. We found that for O. davisae, the ontogenetic variation in specific P content agreed with the reported differences in growth rate along development; however, in the case of P. grani, in which juvenile and adult maximum growth rates are similar, the variations in specific P content along development did not reflect the growth rate pattern.

scholarly journals Individual and interactive effects of warming and CO<sub>2</sub> on <i>Pseudo-nitzschia subcurvata</i> and <i>Phaeocystis antarctica</i>, two dominant phytoplankton from the Ross Sea, Antarctica

2017 ◽  
Vol 14 (23) ◽  
pp. 5281-5295 ◽  
Author(s):  
Zhi Zhu ◽  
Pingping Qu ◽  
Jasmine Gale ◽  
Feixue Fu ◽  
David A. Hutchins
Keyword(s):  
Elemental Composition ◽  
Functional Response ◽  
Growth Rates ◽  
Ross Sea ◽  
Interactive Effect ◽  
Interactive Effects ◽  
Response Curves ◽  
Half Saturation Constant ◽  
Phaeocystis Antarctica ◽  
Effects Of Temperature

Abstract. We investigated the effects of temperature and CO2 variation on the growth and elemental composition of cultures of the diatom Pseudo-nitzschia subcurvata and the prymnesiophyte Phaeocystis antarctica, two ecologically dominant phytoplankton species isolated from the Ross Sea, Antarctica. To obtain thermal functional response curves, cultures were grown across a range of temperatures from 0 to 14 °C. In addition, a co-culturing experiment examined the relative abundance of both species at 0 and 6 °C. CO2 functional response curves were conducted from 100 to 1730 ppm at 2 and 8 °C to test for interactive effects between the two variables. The growth of both phytoplankton was significantly affected by temperature increase, but with different trends. Growth rates of P. subcurvata increased with temperature from 0 °C to maximum levels at 8 °C, while the growth rates of P. antarctica only increased from 0 to 2 °C. The maximum thermal limits of P. subcurvata and P. antarctica where growth stopped completely were 14 and 10 °C, respectively. Although P. subcurvata outgrew P. antarctica at both temperatures in the co-incubation experiment, this happened much faster at 6 than at 0 °C. For P. subcurvata, there was a significant interactive effect in which the warmer temperature decreased the CO2 half-saturation constant for growth, but this was not the case for P. antarctica. The growth rates of both species increased with CO2 increases up to 425 ppm, and in contrast to significant effects of temperature, the effects of CO2 increase on their elemental composition were minimal. Our results suggest that future warming may be more favorable to the diatom than to the prymnesiophyte, while CO2 increases may not be a major factor in future competitive interactions between Pseudo-nitzschia subcurvata and Phaeocystis antarctica in the Ross Sea.

Prey preference, environmental tolerances and ichthyotoxicity by the red-tide dinoflagellate Noctiluca scintillans cultured from Tasmanian waters

2019 ◽  
Vol 41 (4) ◽  
pp. 407-418 ◽  
Author(s):  
Gustaaf M Hallegraeff ◽  
Maria E Albinsson ◽  
Jo Dowdney ◽  
Angela K Holmes ◽  
Maged P Mansour ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Growth Rates ◽  
Red Tide ◽  
Optimal Growth ◽  
Noctiluca Scintillans ◽  
Grazing Impacts ◽  
Beach Tourism ◽  
Key Factor ◽  
Unionized Ammonia ◽  
Culture Growth

Abstract The large phagotrophic dinoflagellate Noctiluca has become a prominent red tide organism in southeast Australian waters since the 2000s, raising concerns for beach tourism, grazing impacts as well as ichthyotoxicity for finfish aquaculture. Satisfactory culture growth rates (0.23–0.56 per day) were obtained by feeding with small Thalassiosira diatom and Tetraselmis flagellate diets, while optimal growth rates sustained for up to 8 months (0.69 per day) were achieved by feeding in a plankton wheel with the large chain-forming dinoflagellate Gymnodinium catenatum. Noctiluca was highly tolerant towards salinities from 20 to 35 and growth was stimulated by temperatures increasing from 10 to 23°C, which in combination with the key factor of prey abundance explains the incidence in southeast Australia of predominantly summer and spring but occasionally also winter blooms. Fatty acid biomarkers suggest that Tasmanian field populations indiscriminately feed on available diatom and dinoflagellate mixtures. Noctiluca exhibited very limited ichthyotoxicity, and only at the highest cell concentrations of 2 000 000/L (50% reduction in RTgill W1 cell viability). Only the densest red tide surface slicks contained acutely toxic levels of unionized ammonia of 242 to 510 μg/L while inshore slicks generated oxygen concentrations as low as 0–1.5 ppm. Lipid phycotoxins (eicosapentaenoic acid, docosahexaenoic acid) did not appear to contribute to Noctiluca ichthyotoxicity. The fatty acid 20:0 eicosanoic acid may serve as a potential Noctiluca biomarker in marine food webs and sediments.

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