scholarly journals Physiological Changes and Elemental Ratio of Scrippsiella trochoidea and Heterosigma akashiwo in Different Growth Phase

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 132
Author(s):  
Xiaofang Liu ◽  
Yang Liu ◽  
Md Abu Noman ◽  
Satheeswaran Thangaraj ◽  
Jun Sun
Keyword(s):  
Organic Nitrogen ◽  
Growth Period ◽  
Heterosigma Akashiwo ◽  
Physiological Changes ◽  
Scrippsiella Trochoidea ◽  
Average Cell ◽  
Physiological Models ◽  
Elemental Ratios ◽  
Chl A ◽  
Elemental Ratio

The elemental ratios in phytoplankton are important for predicting biogeochemical cycles in the ocean. However, understanding how these elements vary among different phytoplankton taxa with physiological changes remains limited. In this paper, we determine the combined physiological–elemental ratio changes of two phytoplankton species, Scrippsiella trochoidea (Dinophyceae) and Heterosigma akashiwo (Raphidophyceae). Our results show that the cell growth period of S. trochoidea (26 days) was significantly shorter than that of H. akashiwo (32 days), with an average cell abundance of 1.21 × 104 cells·mL−1 in S. trochoidea and 1.53 × 105 cells·mL−1 in H. akashiwo. The average biovolume of S. trochoidea (9.71 × 103 μm3) was higher than that of H. akashiwo (0.64 × 103 μm3). The physiological states of the microalgae were assessed based on elemental ratios. The average ratios of particulate organic nitrogen (PON) to chlorophyll-a (Chl-a) and particulate organic carbon (POC) to Chl-a in S. trochoidea (57.32 and 168.16) were higher than those of H. akashiwo (9.46 and 68.86); however, the ratio of POC/PON of the two microalgae was nearly equal (6.33 and 6.17), indicating that POC/Chl-a may be lower when the cell is actively growing. The physiological variation, based on the POC/Chl-a ratio, in different phytoplankton taxa can be used to develop physiological models for phytoplankton, with implications for the marine biogeochemical cycle.

scholarly journals Behavioral and Physiological Changes during Benthic-Pelagic Transition in the Harmful Alga, Heterosigma akashiwo: Potential for Rapid Bloom Formation

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e76663 ◽  
Author(s):  
Elizabeth D. Tobin ◽  
Daniel Grünbaum ◽  
Johnathan Patterson ◽  
Rose Ann Cattolico
Keyword(s):  
Heterosigma Akashiwo ◽  
Physiological Changes ◽  
Harmful Alga ◽  
Bloom Formation

scholarly journals Exploring the controls on element ratios in middle Eocene samples of the benthic foraminifera <i>Oridorsalis umbonatus</i>

2012 ◽  
Vol 8 (6) ◽  
pp. 1957-1971 ◽  
Author(s):  
C. F. Dawber ◽  
A. K. Tripati
Keyword(s):  
Benthic Foraminifera ◽  
Bottom Water ◽  
Middle Eocene ◽  
Environmental Parameters ◽  
Intermediate Water ◽  
Saturation State ◽  
Bottom Water Temperature ◽  
Elemental Ratios ◽  
Elemental Ratio ◽  
Element Ratios

Abstract. Culturing studies and empirically based core top calibrations have been used to infer that elemental ratios in benthic foraminifera can be used as proxies to reconstruct past variations in bottom water temperature and saturation state (Δ [CO32−]). However the mechanisms linking elemental ratios to these parameters are poorly constrained. Here, we explore the environmental parameters influencing the incorporation of B, Li, Sr and Mg in Oridorsalis umbonatus in early Cenozoic sediments from Ocean Drilling Program Site 1209. We investigate the influence of middle Eocene variations in intermediate water Δ [CO32−] using relationships developed from core top samples. The fidelity of bottom water Δ[CO32−] reconstructions based on single element ratios is assessed by comparing the X/Ca-based reconstructions to each other and to carbon cycle proxy records (benthic foraminifera δ13C, organic carbon content, foraminifera dissolution indices), and a seawater δ18O reconstruction for Site 1209. Discrepancies in the reconstructed Δ[CO32−] values based on these different metal ratios suggest that there are still gaps in our understanding of the parameters influencing X/Ca and demonstrate that caution is required when interpreting palaeo-reconstructions that are derived from a single elemental ratio. The downcore record of O. umbonatus Mg/Ca does not exhibit any similarities with the Li/Ca, B/Ca and Sr/Ca records, suggesting that the environmental parameters influencing Mg/Ca may be different for this species, consistent with temperature as the strongest control on this elemental ratio. This hypothesis is supported by the coefficients of multiple linear regression models on published Mg/Ca data. An incomplete understanding of the controls on elemental incorporation into benthic foraminifera hinders our ability to confidently quantify changes in saturation state using single X/Ca reconstructions over a range of timescales.

Studies on Phytoplankton and Particulate Organic Carbon in the Southern Ocean

2011 ◽  
Vol 137 ◽  
pp. 344-352
Author(s):  
Gen Hai Zhu ◽  
Yan Lan Liu ◽  
Li Hong Chen ◽  
Pei Song Yu ◽  
Mao Jin ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Southern Ocean ◽  
Particulate Organic Carbon ◽  
Euphotic Zone ◽  
Study Data ◽  
Phytoplankton Abundance ◽  
Average Cell ◽  
Chl A ◽  
Cell Abundance ◽  
Phytoplankton Cell

Using China Southern Ocean’s study data collected from 1989 to 2009 year, this paper analyzed the related characteristics between phytoplankton abundance, Ch1 a concentrations and particulate organic carbon. The average cell abundance of Southern Ocean phytoplankton was 7.38×104 cells/dm3. The dominant species of Southern Ocean phytoplankton were Fragilariopsis kerguelensis, Fragilariopsis curta, Pseudo-nitzschia lineola, Eucampia antarctica, Thalassiosira antarctica and Corethron criophilum and son on. In Prydz Bay of the Southern Ocean, the contribution of phytoplankton cell abundance and phytoplankton carbon toward particulate organic carbon were higher than that in the Northern Gulf Ocean Area. In the upper layer of euphotic zone, the contribution of phytoplankton abundance and phytoplankton carbon toward particulate organic carbon were higher than that in the deep water district. Through analysis of regressive statistics, phytoplankton cell abundance (y) and particulate organic carbon (POC) and chlorophyll a (Chl a) were a remarkable positive correlation.

Influence of dinoflagellate diurnal vertical migrations on dimethylsulfoniopropionate and dimethylsulfide distribution and dynamics (St. Lawrence Estuary, Canada)

2004 ◽  
Vol 61 (5) ◽  
pp. 712-720 ◽  
Author(s):  
Anissa Merzouk ◽  
Maurice Levasseur ◽  
Michael Scarratt ◽  
Sonia Michaud ◽  
Michel Gosselin
Keyword(s):  
Vertical Migration ◽  
De Novo ◽  
Physiological Responses ◽  
Alexandrium Tamarense ◽  
Scrippsiella Trochoidea ◽  
Lawrence Estuary ◽  
Chl A ◽  
Diel Variations ◽  
St Lawrence Estuary ◽  
Diurnal Vertical Migrations

The influence of the diurnal vertical migration of the dinoflagellates Alexandrium tamarense and Scrippsiella trochoidea on dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics was studied during a 34-h Lagrangian experiment in the St. Lawrence Estuary in July 2000. Particulate DMSP (DMSPp), dissolved DMSP (DMSPd), and DMS exhibited diel patterns with minimum concentrations during the night and maximum concentrations around noon. DMSPp concentrations were correlated with the abundance of the two vertically migrating DMSP-rich dinoflagellates. The DMSPp:Chl a ratio exhibited similar diel variations, suggesting a light-induced de novo DMSP synthesis during the day. Diel variations of the DMS:Chl a ratio suggest that the accumulation of DMS around noon resulted from physiological responses of the algae and (or) bacteria to light. Biological gross DMS production and bacterial DMS consumption were decoupled, leading to rapid fluctuations in DMS. These results show that in systems dominated by DMSP-rich dinoflagellates containing DMSP lyases, DMS concentrations may vary by as much as a factor of 10 over a 24-h period. Such diel variations must be considered when estimating the contribution of such systems to the DMS sea to air flux.

scholarly journals Generalized Stoichiometry and Biogeochemistry for Astrobiological Applications

2021 ◽  
Vol 83 (7) ◽  
Author(s):  
Christopher P. Kempes ◽  
Michael J. Follows ◽  
Hillary Smith ◽  
Heather Graham ◽  
Christopher H. House ◽  
...  
Keyword(s):  
The Body ◽  
Cell Physiology ◽  
Theoretical Treatment ◽  
Physiological Models ◽  
Elemental Ratios ◽  
Chemical Systems ◽  
Classic Work ◽  
Planetary Missions ◽  
Key Questions

AbstractA central need in the field of astrobiology is generalized perspectives on life that make it possible to differentiate abiotic and biotic chemical systems McKay (2008). A key component of many past and future astrobiological measurements is the elemental ratio of various samples. Classic work on Earth’s oceans has shown that life displays a striking regularity in the ratio of elements as originally characterized by Redfield (Redfield 1958; Geider and La Roche 2002; Eighty years of Redfield 2014). The body of work since the original observations has connected this ratio with basic ecological dynamics and cell physiology, while also documenting the range of elemental ratios found in a variety of environments. Several key questions remain in considering how to best apply this knowledge to astrobiological contexts: How can the observed variation of the elemental ratios be more formally systematized using basic biological physiology and ecological or environmental dynamics? How can these elemental ratios be generalized beyond the life that we have observed on our own planet? Here, we expand recently developed generalized physiological models (Kempes et al. 2012, 2016, 2017, 2019) to create a simple framework for predicting the variation of elemental ratios found in various environments. We then discuss further generalizing the physiology for astrobiological applications. Much of our theoretical treatment is designed for in situ measurements applicable to future planetary missions. We imagine scenarios where three measurements can be made—particle/cell sizes, particle/cell stoichiometry, and fluid or environmental stoichiometry—and develop our theory in connection with these often deployed measurements.

Effect of Initial Phosphorus Concentration on Chlorophyll a Contents and Extracellular Polysaccharides Contents of Scenedesmus quaclricauda in TGR

2014 ◽  
Vol 971-973 ◽  
pp. 53-58
Author(s):  
Qiang An ◽  
Sha Wang ◽  
Ce Wang ◽  
Niu Qiu Huang ◽  
Byebirooha Justus
Keyword(s):  
Chlorophyll A ◽  
Growth Period ◽  
Inhibitory Effect ◽  
Extracellular Polysaccharides ◽  
Phosphorus Concentration ◽  
Lag Phase ◽  
Chl A ◽  
The Three Gorges ◽  
Significant Difference ◽  
In The Beginning

An experiment was carried out to evaluate the effects of initial phosphorus concentration (0, 0.54, 2.7, 5.4, 10.8and 16.2mg/L) on chlorophyll a (chl-a) contents and extracellular polysaccharides (EPS) contents of Scenedesmus quaclricauda, which was separated and purified from the Three Gorges reservoir (TGR). The different conditions of initial phosphorus concentration have different volumetric meanings. 0mg/L, 0.54mg/L and 2.7mg/L are P-limited, 5.4mg/L is P-standard, 10.8mg/L as well as 16.2mg/L, is P-rich. Results showed that the growth period of Scenedesmus quaclricauda was shortened, and the stationary phase happened earlier than usual in the condition of P-limited. However, the growth period of Scenedesmus quaclricauda got a proceeding extension in the condition of P-rich. The condition of P-rich had an inhibitory effect on the growth of Scenedesmus quaclricauda during lag phase and exponential phase. It seemed that there was an inhibition threshold of initial phosphorus concentration, which was between 5.4mg/L and 10.8mg/L. And the inhibitory effect decreased with the initial increasing phosphorus concentrations from 10.8mg/L to 16.2mg/L. One-way analysis of variance (ANOVA) was used to compare the effects of both P-limited and P-rich and their impact on sEPS contents and bEPS contents of Scenedesmus quaclricauda in the cultured time segments. The results showed that there was no significant difference at sEPS contents or bEPS contents either in P-limited or P-rich. In the whole culture period, the sEPS contents of Scenedesmus quaclricauda had small fluctuations but kept nearly unchanged. Whereas, the bEPS contents increased in the beginning 8 days, and then dropped to the level, which is slightly higher than the initial contents, and keep fluctuating steadily. The EPS contents were just floating up and down at the initial value and had not shown a trend of rising or falling precisely. Our results suggest that phosphorus concentration could change chl-a contents but have no significant effect on EPS contents.

scholarly journals Facile synthesis of Cu/Ni alloy nanospheres with tunable size and elemental ratio

RSC Advances ◽  
2017 ◽  
Vol 7 (60) ◽  
pp. 37823-37829 ◽  
Author(s):  
Jinglei Liu ◽  
Yiqun Zheng ◽  
Shifeng Hou
Keyword(s):  
High Purity ◽  
Facile Synthesis ◽  
Elemental Ratios ◽  
Elemental Ratio ◽  
Copper Nickel ◽  
Ni Alloy

We report a facile synthesis of copper/nickel (Cu/Ni) alloy nanospheres in high purity and with tunable, well-controlled sizes and elemental ratios.

Photosynthetic Characteristics of Lotic Periphyton

1986 ◽  
Vol 43 (10) ◽  
pp. 1960-1969 ◽  
Author(s):  
Stephen Jasper ◽  
Max L. Bothwell
Keyword(s):  
Light Level ◽  
Early Spring ◽  
Initial Slope ◽  
Late Winter ◽  
Photosynthetic Parameters ◽  
Average Cell Size ◽  
Average Cell ◽  
Chl A ◽  
Limiting Nutrient ◽  
Light History

Periphyton communities, grown in continuous-flow troughs, were suspended in filtered river water and placed in a photosynthesis–light incubator similar to those used for phytoplankton. A three-parameter equation was fitted to the incubator data. Seasonally the initial slope, α, ranged from 12.1 to 53.6 μg C∙(mg Chl a)−1∙h−1∙(μEinst.∙m−2∙s−1)−1; the maximum photosynthetic rate, PBmax, varied from 1.16 to 5.49 mgC∙(mg Chl a)−1∙h−1; and the inhibition parameter, Ib, ranged from 1500 to 6900 μEinst.∙m−2∙s−1. These values are similar to those reported for other periphyton and phytoplankton. PBmax strongly correlated with light history, whereas inhibition was inversely related to water temperature, α did not correlate with either irradiance or temperature but with changes in average cell size. Seasonal variations in the light level optimal for photosynthesis, Im, suggested a period in late winter and early spring for potentially serious inhibition of photosynthesis. These Chl a normalized photosynthetic parameters were unaffected by changes in concentration of the growth-limiting nutrient, phosphorus.

scholarly journals Overexpression of OsSPL14 results in transcriptome and physiology changes in indica rice ‘MH86’

2020 ◽  
Vol 90 (2) ◽  
pp. 265-278 ◽  
Author(s):  
Ling Lian ◽  
Huibin Xu ◽  
Hui Zhang ◽  
Wei He ◽  
Qiuhua Cai ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Indica Rice ◽  
Critical Role ◽  
Lignin Biosynthesis ◽  
Growth Period ◽  
Carotenoid Biosynthesis ◽  
Transcriptional Level ◽  
Chl A ◽  
Rice Plants ◽  
Transgenic Lines

AbstractOryza sativa SPL14 (OsSPL14), identified as the IDEAL PLANT ARCHITECTURE1 or WEALTHY FARMER’S PANICLE gene, plays a critical role in regulating rice plant architecture. Here, OsSPL14-overexpression transgenic rice plants had shorter growth periods, short narrow flag leaves, and thick green leaves compared with wild type ‘MH86’ plants (WT). Additionally, transgenic lines had higher chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoid (Car x) contents at both seedling and mature stages. Expression of OsSPL14 increased at transcriptional level, and OsSPL14 protein level was substantially increased in transgenic lines relative to WT. A transcriptome analysis identified 473 up-regulated and 103 down-regulated genes in the transgenic plants. The expression of differentially expressed genes (DEGs) involved in carotenoid biosynthesis, abscisic acid (ABA) metabolism, and lignin biosynthesis increased significantly. Most of DEGs participated in “plant hormone signal transduction” and “starch and sucrose metabolism” were also up-regulated in the transgenic plants. In addition, there were higher ABA and gibberellin acid 3 (GA3) levels in OsSPL14-overexpression rice plants at seedling and tillering stages compared with WT. In contrast with that of WT, lignin and cellulose contents of culm increased distinctly. Also, silicon and potassium contents increased dramatically in transgenic lines. Meanwhile, the chalkiness ratios and chalkiness degrees decreased, and the gel consistency levels improved in transgenic lines. Thus, overexpression of OsSPL14 influenced growth period, leaf development, hormonal levels, culm composition, and grain quality characters of rice, which provides more insight into the function of OsSPL14.

Sign in / Sign up

Export Citation Format

Share Document