Carbon to chlorophyll-a ratio in modeling long-term eutrophication phenomena

1998 ◽  
Vol 38 (11) ◽  
pp. 227-235 ◽  
Author(s):  
Haisheng Jin ◽  
Shinji Egashira ◽  
K. W. Chau
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Present Method ◽  
Bottom Water ◽  
Specific Growth ◽  
Weighted Average ◽  
Anoxic Condition ◽  
Ambient Conditions

Carbon to chlorophyll-a ratio (CCHL) is formulated based on the assumption that adaptive changes in carbon to chlorophyll occur so as to maximize the specific growth rate for ambient conditions, including solar radiation and water temperature. With the dynamic CCHL, an unsteady two-layered, two-dimensional eutrophication numerical model for density stratified coastal waters has been developed. Saturated light intensity (IS) is determined as weighted average of the light intensity for previous three days to incorporate light acclimation by phytoplankton. The bottom water anoxic condition during summer in Tolo Harbour, Hong Kong is successfully reproduced by the present method. Otherwise, the simulation with a constant CCHL gave a wrong result.

Diel Periodicity of Chlorophyll a Concentration in Oregon Coastal Waters

1972 ◽  
Vol 29 (9) ◽  
pp. 1253-1259 ◽  
Author(s):  
Walter A. Glooschenko ◽  
Herbert Curl Jr. ◽  
Lawrence F. Small
Keyword(s):  
Light Intensity ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Dark Period ◽  
Skeletonema Costatum ◽  
Time Of Day ◽  
Light Period ◽  
Diel Periodicity ◽  
Low Light ◽  
Chlorophyll Precursor

Concentrations of chlorophyll a in phytoplankton exhibited a diel periodicity in Oregon coastal waters. Maximum surface concentrations often occurred around midnight and highest 25-m concentrations early in the evening (or even in late afternoon). Concentrations at intermediate depths fell in between and in a predictable progression with depth and time of day. Minimum chlorophyll a values occurred in the afternoon. No definite periodicity was established at 50 m.Laboratory studies with Skeletonema costatum demonstrated that the diel cycle of chlorophyll a per cell was related to the light intensity and duration to which cells were exposed. Highest concentrations of this pigment occurred early in the dark period and lowest concentrations in the light period when cells were grown under photoperiods of 9, 12, and 15 hr at a light intensity of approximately 1200 ft-c. Pigment bleaching probably was responsible for the low concentrations during the light period. The decline of chlorophyll a from the maximum early in the dark period began after the cells possibly became deficient in some chlorophyll precursor or energy-yielding substrate. Addition of an external carbon source during the dark period prolonged the high chlorophyll a concentrations in the dark before the decline began. Under low light (400 ft-c) chlorophyll a synthesis occurred only in the light. This phenomenon was most likely due to an insufficient amount of energy-yielding substrate or precursor synthesized during the low-light period, and the lack of bleaching in the light period at this lower intensity. The laboratory results were consistent with interpretations of the field data. A correction for diel pigment periodicity is recommended for models estimating photosynthesis from chlorophyll and light data and for oceanographic surveys during which sampling of chlorophyll a is carried out throughout the 24-hr day.

Long-term chlorophyll-a dynamics in tropical coastal waters of the western Bay of Bengal

2019 ◽  
Vol 27 (6) ◽  
pp. 6411-6419 ◽  
Author(s):  
Aneesh Anandrao Lotliker ◽  
Sanjiba Kumar Baliarsingh ◽  
Kali Charan Sahu ◽  
Tummala Srinivasa Kumar
Keyword(s):  
Chlorophyll A ◽  
Bay Of Bengal ◽  
Coastal Waters ◽  
Western Bay Of Bengal

scholarly journals Growth, biomass, and chlorophyll-a and carotenoid content of Nannochloropsis sp. strain BJ17 under different light intensities

2017 ◽  
Vol 16 (1) ◽  
pp. 15
Author(s):  
Muhammad Fakhri ◽  
Nasrullah Bai Arifin ◽  
Anik Martina Hariati ◽  
Ating Yuniarti
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Chlorophyll A ◽  
Specific Growth ◽  
Cell Concentration ◽  
Carotenoid Content ◽  
Biomass Growth ◽  
Live Feed ◽  
Light Intensities ◽  
Effect Of Light

<p class="Pa3"><strong>ABSTRACT </strong></p><p> </p><p class="Pa5"><em>Nannochloropsis </em>sp. has been identified as sources of live feed and pigment in aquaculture. To increase the production, the optimal environmental conditions for microalgae are required. Light intensity is one of the important factors that significantly affects the biomass and pigment of microalgae. The study aimed to determine the effect of light intensity (1,500; 3,000; and 4,500 lux) on growth, biomass production, chlorophyll-a, and carotenoid content of <em>Nannochloropsis </em>sp. strain BJ17. The results showed that different light intensities significantly affected the growth, biomass, chlorophyll-a and carotenoid contents of <em>Nannochloropsis </em>sp. strain BJ17. Increasing light intensity resulted in the increase of the growth rate, biomass, chlorophyll-a, and carotenoid contents of <em>Nannochloropsis </em>sp. strain BJ17. The cell achieved the highest specific growth rate of 1.729 %/day and the cell concentration of 43.333×106 cell/mL at a light intensity of 4,500 lux. The highest chlorophyll-a and carotenoid concentrations of algae were obtained at 4,500 lux (8.304 μg/mL and 3.892 μg/mL, respectively). This study suggested that increasing light intensity led to the increase in the growth, biomass, chlorophyll-a, and carotenoid content of <em>Nannochloropsis </em>sp. strain BJ17.</p><p> </p><p class="Pa5">Keywords: carotenoid, chlorophyll, biomass, growth rate, light intensity</p><p> </p><p> </p><p class="Pa3"><strong>ABSTRAK </strong></p><p> </p><p class="Pa5"><em>Nannochloropsis </em>sp. diketahui sebagai sumber pakan alami dan pigmen pada budidaya perikanan. Budidaya pada kondisi lingkungan yang optimal diperlukan untuk meningkatkan produksi mikroalga. Intensitas cahaya merupakan salah satu faktor esensial yang secara signifikan mempengaruhi biomassa dan pigmen mikroalga. Tujuan penelitian ini adalah untuk menentukan pengaruh intensitas cahaya yang berbeda (1.500, 3.000, and 4.500 lux) terhadap pertumbuhan, produksi biomassa, klorofil-a, dan karotenoid <em>Nannochloropsis </em>sp. strain BJ17. Hasil menunjukkan bahwa intensitas cahaya yang berbeda berpengaruh secara signifikan terhadap pertumbuhan, biomassa dan klorofil-a dan karotenoid <em>Nannochloropsis </em>sp. strain BJ17. Semakin tinggi intensitas cahaya maka laju pertumbuhan, biomassa, kandungan klorofil-a dan total karotenoid <em>Nannochloropsis </em>sp. strain BJ17 semakin tinggi. Laju pertumbuhan spesifik tertinggi 1,729%/hari dan konsentrasi sel maksimum tertinggi 43,333×106 sel/mL dihasilkan pada intensitas cahaya 4.500 lux. Konsentrasi klorofil-a (8,304 μg/mL) dan karotenoid (3,892 μg/mL) tertinggi juga diperoleh pada intensitas cahaya 4.500 lux. Studi ini menunjukkan bahwa peningkatan intensitas cahaya berperan dalam meningkatkan pertumbuhan, produksi biomassa, klorofil-a, dan karotenoid <em>Nannochloropsis </em>sp. strain BJ17.</p><p> </p><p>Kata kunci: karotenoid, klorofil, biomassa, pertumbuhan, intensitas cahaya</p>

scholarly journals Development of phytoplankton in the winter-spring period in the coastal waters of Crimea

2021 ◽  
Vol 6 (1) ◽  
pp. 102-114
Author(s):  
Z. Z. Finenko ◽  
I. M. Mansurova ◽  
I. V. Kovalyova ◽  
E. Yu. Georgieva
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Chlorophyll A ◽  
Black Sea ◽  
Coastal Waters ◽  
Specific Growth ◽  
Shelf Zone ◽  
The Black Sea ◽  
Chlorophyll A Concentration ◽  
Spring Period

The analysis of phytoplankton in the winter-spring period is important for investigating peculiarities of its annual dynamics and the Black Sea ecosystem overall functioning. Phytoplankton state in the winter-spring period in the Black Sea shelf zone is less studied than that of the summer-autumn season; conducting such a research is especially important for solving several problems, related to the productivity of the last links of the food chain, the formation of water hydrochemical regime, and the carbon cycle in the sea. The aim of the work is to assess the effect of seasonal conditions on the development of phytoplankton and its production estimates in the winter-spring period in the coastal waters of Crimea. The article presents the results of studies of hydrophysical (water temperature, density, and relative transparency) and biological indicators (chlorophyll a concentration, its fluorescence, taxonomic composition, and phytoplankton production estimates) in the Black Sea shelf zone in January – April 2016–2019. The studies were carried out at 50 stations, located in the coastal waters of Crimea from the Karkinitsky Bay to the Kerch Strait. Chlorophyll a concentration was measured by the standard fluorometric method, species composition was determined by microscopy, and phytoplankton specific growth rate was calculated according to the previously developed model. In winter (January – February), the values of chlorophyll a content and upper mixed layer depth were the highest (0.42–0.52 mg·m−3 and 44–58 m, respectively); in spring (March – April) they were 2–3 times lower. In January – February, the coccolithophore species Emiliania huxleyi (Lohmann) W. W. Hay & H. P. Mohler, 1967 predominated; in March – April, in different years, either dinoflagellates and diatoms or coccolithophores, dinoflagellates, and diatoms prevailed. In winter, chlorophyll a vertical distribution at most stations was uniform; in spring, unimodal profiles with a depth maximum prevailed, the location of which was not related to temperature and density gradients. Relative changes in chlorophyll a concentration and fluorescence with depth were usually the same. Phytoplankton production and daily production/biomass ratio (P/B) increased from winter to spring. There was no correlation between the values of integral production, biomass, and maximum specific growth rate of algae. Maximum specific growth rate was the least variable indicator. During the winter-spring period, algae in the photosynthetic zone divided on average once every 2–5 days.

Oithona davisae: naturalization in the Black sea, inter-annual and seasonal dynamics, effect on the structure of the planktonic copepod community

2019 ◽  
Vol 59 (6) ◽  
pp. 1008-1015
Author(s):  
A. D. Gubanova ◽  
O. A. Garbazey ◽  
D. A. Altukhov ◽  
V. S. Mukhanov ◽  
E. V. Popova
Keyword(s):  
Black Sea ◽  
Coastal Waters ◽  
Native Species ◽  
Significant Decline ◽  
Acartia Tonsa ◽  
The Black Sea ◽  
Copepod Community ◽  
Oithona Davisae ◽  
Sevastopol Bay

Long-term (20032014) routine observations of zooplankton in Sevastopol Bay (the Black Sea) have allowed the naturalization of the invasive copepod Oithona davisae to be studied in the Black Sea coastal waters. Inter-annual and seasonal variability of the species and their impact on the native copepod community have been analyzed. The invasion of O. davisae and their undoubted dominance in terms of abundance were shown to alter the community structure but, at the same time, the abundances of the native species did not decrease, excepting the Black Sea earlier invader Acartia tonsa. A significant decline in A. tonsa numbers over the stages of O. davisae establishment and naturalization provided evidence of competition between the species. O. davisae have been demonstrated to gain competitive advantage over A. tonsa, that ensured their fast dispersal in the Black Sea, acclimatization in the new habitat and the successful competition over native species.

scholarly journals Quality-control tests for OC4, OC5 and NIR-red satellite chlorophyll-a algorithms applied to coastal waters

2021 ◽  
Vol 255 ◽  
pp. 112237
Author(s):  
H. Lavigne ◽  
D. Van der Zande ◽  
K. Ruddick ◽  
J.F. Cardoso Dos Santos ◽  
F. Gohin ◽  
...  
Keyword(s):  
Quality Control ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Satellite Chlorophyll

scholarly journals Remote sensing of sun-induced chlorophyll-a fluorescence in inland and coastal waters: Current state and future prospects

2021 ◽  
Vol 262 ◽  
pp. 112482
Author(s):  
Remika S. Gupana ◽  
Daniel Odermatt ◽  
Ilaria Cesana ◽  
Claudia Giardino ◽  
Ladislav Nedbal ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Chlorophyll A Fluorescence ◽  
Future Prospects ◽  
Current State

scholarly journals Long-term stability in γ-CsPbI3 perovskite via an ultraviolet-curable polymer network

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Nam-Kwang Cho ◽  
Hyun-Jae Na ◽  
Jeeyoung Yoo ◽  
Youn Sang Kim
Keyword(s):  
Polymer Network ◽  
Lone Pair ◽  
Ambient Conditions ◽  
Absorption Properties ◽  
Term Stability ◽  
Long Term Stability ◽  
Ultraviolet Curable ◽  
Oxygen Lone Pair ◽  
Lone Pair Electrons

AbstractBlack-colored (α, γ-phase) CsPbI3 perovskites have a small bandgap and excellent absorption properties in the visible light regime, making them attractive for solar cells. However, their long-term stability in ambient conditions is limited. Here, we demonstrate a strategy to improve structural and electrical long-term stability in γ-CsPbI3 by the use of an ultraviolet-curable polyethylene glycol dimethacrylate (PEGDMA) polymer network. Oxygen lone pair electrons from the PEGDMA are found to capture Cs+ and Pb2+ cations, improving crystal growth of γ-CsPbI3 around PEGDMA. In addition, the PEGDMA polymer network strongly contributes to maintaining the black phase of γ-CsPbI3 for more than 35 days in air, and an optimized perovskite film retained ~90% of its initial electrical properties under red, green, and blue light irradiation.

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