Dynamics Of Chlorophyll Research Articles

Nutrient, chlorophyll and caloric dynamics of Phyllostachys pubescens leaves in Yongchun County, Fujian, China

Nutrient, chlorophyll and caloric dynamics of the mature and senescent leaves of Phyllostachys pubescens were studied in Yongchun County, Fujian, China, from April 2002 to March 2003. There were notable seasonal variations in nutrient concentrations in the mature and senescent leaves. Mature leaves had significantly higher N, P and K concentrations than senescent leaves, while senescent leaves had higher Ca concentration and Mg concentration changed little during senescence. Resorption efficiencies on leaf area basis of N, P and K were positive, and those of Ca and Mg were negative, suggesting that with leaf senescence, N, P and K were translocated out of senescing leaves to other parts of plant, while Ca and Mg accumulated in senescing leaves. Seasonal changes in Chl a, Chl b and total chlorophyll were curvilinear in style, with Chl a making up the major portion of total chlorophyll. Chl a increased substantially in winter in mature leaves only, reflecting that the photosynthetic apparatus of mature leaves adapted to changes in the environment (i.e., temperature), whilst senescent leaves were less sensitive to environmental changes. Chlorophyll content decreased but the Chl a/Chl b ratio increased during leaf senescence. Ph. pubescens leaves had relatively high ash contents, with 10.29 ± 2.59% for mature leaves and 10.82 ± 2.63% for senescent leaves respectively. There was an increasing trend (P = 0.0199) in the ash content during leaf senescence, showing that Ph. pubescens leaves possibly possessed the mechanism to maintain the nutrition balance. Gross caloric value and ash free caloric value remained almost constant during leaf senescence (P > 0.05), demonstrating that energy was not lost with leaf senescence.

Effects of Short-term Red Radiation and Choline Compounds on Cytokinin Content, Chlorophyll Accumulation and Photomorphogenesis in Wheat Seedlings

Effects of choline compounds (2-chloroethyltrimethylammonium chloride and 2-ethyltrimethylammonium chloride) as well as red radiation (R) pulse on the dynamics of cytokinin changes, growth and chlorophyll (a + b) accumulation were studied during the growth and greening of etiolated wheat seedlings (Triticum aestivum L., var. Mironovskaya-808). The seedlings were grown for 120 h in the dark and then exposed for 72 h to white light. Pre-treatment of caryopses with cholines and pre-irradiation of etiolated seedlings with R inhibited elongation of both coleoptile and first leaf; but the same factors accelerated these growth responses when seedlings were exposed to white light. Chlorophyll (Chl) accumulation and the first leaf appearance from coleoptile were accelerated by the pre-treatments as well. Far-red radiation (FR) reversed all effects of R but choline pre-treatment eliminated partly R/FR photoreversibility. Two compounds with high cytokinin activity (tested on a fresh weight basis by the bioassay with Amaranthus caudatus L.) were found in shoots and first leaves. One of them had Rf, UV absorbance spectrum and the biological activity similar to N6-(Δ2-isopentenyl)adenosine. Another cytokinin-like substance was not identified with the used standards. Stimulation of greening by R pulse and cholines was accompanied with accelerated accumulation of both cytokinin-like substances. We conclude that the influence of R and cholines on the concentration of substances with cytokinin activities detected in the leaves might be involved in the stimulation of Chl accumulation.

Dynamic chloroplast pigments concentration in leaves of soybean ( Glycine max [L.] Merr.) under reduced tillage

The objectives of this experiment were to determine the chloroplast pigments dynamics of soybean leaves during the growth stages under different tillage systems, which can be a major factor limiting yield of soybean. The greatest differences between the photosynthetic productivity parameters of the investigated soybean were determined from reproductive stages (R2 and R3 – 4). The chlorophyll a, chlorophyll a/b and carotenoids content under CT, DH and NT were greater in the reproductive stages (R2 and R3 – 4) than in the early stages (V3 – 4 and R1). The concentration dynamics of chlorophyll b and chlorophyll a/b was very similar in all growth stages and under all tillage systems in the 2-yr average. The increased drought stress in 2003 was likely critical in the observed lower seed yields in 2003. The yield of soybean was significantly lower under NT than CT and DH treatments in both years. The relationship between the soybean yield and chloroplast pigments concentration is strongly influenced by external factors. In the 2-yr average the soybean yield was considerably affected by the years and tillage systems. Statistical analysis showed a very significant relationship between chlorophyll pigments content, but photosynthetic parameters investigated did not correlate with soybean yield.

Ecosystem indicators derived from satellite remotely sensed oceanographic data for the North Pacific

Abstract Satellite remotely sensed oceanographic data provide reliable global ocean coverage of sea surface temperature, sea surface height, surface winds, and ocean colour, with relatively high spatial and temporal resolution. We illustrate approaches to use these data to construct indicators that describe aspects of ecosystem dynamics in the North Pacific. Specifically, altimetry data are used to construct regional indicators of the ocean vertical structure, ocean colour data to describe the temporal chlorophyll dynamics of the coastal zone, ocean colour, sea surface temperature, and altimetry data to develop indices of biologically important ocean features, and finally altimetry data to drive a larval transport model and develop an index of larval retention. Recent changes in the North Pacific based on these indices are discussed.

On Seasonal Dynamics of the Biomass of Phytoplankton in the Volga Reservoirs

Results of the study suggest that the Ivankovo, Kuybyshev, and Saratov reservoirs of the Volga river cascade differing in their morphometric and hydrological characteristics were closely similar in seasonal dynamics of chlorophyll a content.

Relationship between Long-Term Dynamics of Chlorophyll a Content in Plankton of the Dnieper Reservoirs and the Total Solar Radiation and its Activity

Relationship between Long-Term Dynamics of Chlorophyll a Content in Plankton of the Dnieper Reservoirs and the Total Solar Radiation and its Activity

Selected Features of the Distribution of Chlorophyll along the Southern Shore of Lake Superior

Monitoring was conducted over the April to October interval of 1999 and 2000, seeking signals in the spatiotemporal structure of algal biomass (chlorophyll) in Lake Superior. Sampling was conducted along three nearshore-offshore transects in the vicinity of Michigan's Keweenaw Peninsula. Levels of algal biomass in Lake Superior are the lowest in the Great Lakes, with chlorophyll concentrations ranging from ∼0.25 to 2.5 mg·m −3 and averaging less than 1 mg·m −3 in the surface waters. Several spatial signals were observed, including inter-transect differences, nearshore-offshore gradients, and vertical structure. These signals are thought to be mediated by several factors, including runoff from a major tributary, light availability and mixing depth, inter-transect variations in bathymetry and temperature gradients, e.g., the thermal bar in spring and vertical stratification in summer. Seasonally, surface water chlorophyll dynamics were characterized by an increase from late-winter concentrations in late April and early May, a continued increase in the nearshore and a decrease/stabilization at offshore sites from late May through July, a summer minimum in late July and August and an increase in September and October with the approach to turnover. These signals are striking given the modest levels of chlorophyll present in the lake and considering prevailing conditions of light, temperature and phosphorus availability. The spatial and temporal structure evidenced here likely resonates through the system, impacting the distribution of organisms both higher and lower in the food web. These results will find application in this and other similar systems for consideration of the vernal thermal bar as a factor mediating primary production and cross-margin transport of materials of biogeochemical significance, in developing a greater appreciation of the role of the microbial loop in fostering secondary production, in defining the relative roles of allochthonous and autochthonous contributions to the carbon budget and in supporting remote sensing studies of large scale transport phenomena in the lake.

Spatial and temporal anomalies of sea surface temperature in global scale (by space-based data)

The work presents the data on the spatial distribution of temperature anomalies in the Global Ocean, based on the long-term measurements with the AVHRR satellite equipment. It is noteworthy that such results can be only obtained by using long time series of satellite images. To obtain them by ship-borne methods is actually impossible. The proposed anomaly criterion is equal to a difference between minimum/maximum and average temperature, normed for the mean square deviation. The difference is calculated from the whole time series (with regard to a season). Based on this criterion, anomalies can be distinguished on the background of usual seasonal dynamics at various absolute values of deviations of the measured parameter. Besides, rare, single, fluctuations can be also revealed. Based on the proposed criterion, connected zones have been defined. These zones occur almost in every part of the Global Ocean. The data obtained have been analyzed in association with the CZCS (1978–1986) and SeaWiFS satellite images in order to compare them with the areas of anomalous dynamics of chlorophyll concentration and the regions quasistationary in the seasonal dynamics of chlorophyll. Anomalies in the temperature dynamics are of exceptional importance for the formation of climatic deviations; they affect the ocean–atmosphere interaction and reflect variations in the hydrological structure of the surface waters. The work presents a comparison with the dynamics of chlorophyll concentration distribution determined from the SeaWiFS data for the Atlantic Ocean.

Chlorophyll Dynamics in Rice (Oryza sativa) Before and After Flowering Based on SPAD (Chlorophyll) Meter Monitoring and its Relation with Grain Yield

The rice plant at any point in time is composed of leaves of physiologically different ages, so it follows that the leaves differ in their contributions to the growth of the whole plant and its grain yield. As the leaf chlorophyll content (Soil Plant Analytical Division value) is the best indicator of photosynthetic activity in rice, the chlorophyll content of rice before and after flowering was determined in a weed management field experiment on direct wet seeded rice. The results indicated that the leaf chlorophyll content at 79 days after sowing correlated well with the grain yield of rice. Multiple regression models also indicated the dependence of rice yield on leaf chlorophyll content before and after flowering.

Predicting eutrophication effects in the Burrinjuck Reservoir (Australia) by means of the deterministic model SALMO and the recurrent neural network model ANNA

Two modelling paradigms were applied to the prediction of phytoplankton abundance in the Burrinjuck Reservoir: the deductive model SALMO and the inductive model ANNA. While SALMO is driven by process-based differential equations, the model ANNA is designed as recurrent feedforward neural network trained by time series data. Predictions of chlorophyll- a for the years 1979–1982 by both models were validated by means of measured data. Results showed that SALMO is able to predict annual average trends not only of chlorophyll- a but other chemical and biological state variables as well. It supports decision making by evaluating alternative scenarios for strategic eutrophication control. The model ANNA achieved reasonable accuracy in predicting timing and magnitudes of algal biomass up to 7 days ahead. The recurrent feedforward architecture of ANNA proved to be most efficient in order to model and predict seasonal dynamics of chlorophyll- a and its forecasting results can be utilized for early warning and tactical control of algal blooms in freshwater lakes. A sensitivity analysis conducted by ANNA revealed that algal abundance in Burrinjuck Reservoir is not only driven by physical and chemical characteristics of the water body but to a large extend by hydrological characteristics such as water depth as well.

Dynamics of C2 toxin and chlorophyll- a formation in the dinoflagellate Alexandrium tamarense during large scale cultivation

The production of paralytic shellfish toxins (PSTs) by the dinoflagellate Alexandrium tamarense ATCI01, a toxigenic strain isolated from South China coastal waters, was studied in batch cultures in relatively large volumes (20 l). Under nutrient-replete conditions, this strain produced C2 toxin (C2T) as a predominant PST. In a 15-day production culture, phosphate was depleted by day 4, the stationary phase began at day 6, and the toxin productivity peaked at day 10, in which the cell content of C2T reached 76 fmol per cell. Much of the toxin was produced after the depletion of phosphate in the medium suggesting that C2T is a secondary metabolite. Aeration with small bubbles was useful in increasing cell mass and toxin yield. Chlorophyll- a (Chl- a) was formed in algal cells until the culture entered the stationary phase, after which Chl- a began to disappear rapidly from the culture while the C2T content continued to rise. These results suggest a metabolic relationship between Chl- a and C2T.

The Use of Pigment Signatures to Assess Phytoplankton Assemblage Structure in Estuarine Waters

The seasonal dynamics of chlorophyll a and the main accessory pigments accompanied by microscopic observations on live and fixed material were investigated in the Urdaibai estuary, Spain. Fucoxanthin was the dominant pigment during the peak in chlorophyll a, with which it was strongly correlated. Concentrations of fucoxanthin (81·30μgl−1) in the upper estuary were amongst the highest found in the literature, and were mainly associated with diatoms and symbiotic dinoflagellates. In the lower estuary, fucoxanthin showed values typical of coastal waters (<5μgl−1) and was mainly due to diatoms and prymnesiophytes. Chlorophyllb concentration was high along the estuary, followed the same seasonal pattern as chlorophyll a, and was associated with the presence of euglenophytes, chlorophytes and prasinophytes. High values of 19′-butanoyloxyfucoxanthin were often measured, but no organisms containing this pigment were observed in live or fixed samples. Alloxanthin and peridinin were found in low concentrations which was in agreement with cell counts of cryptophytes and peridinin-containing dinoflagellates. Two main patterns of phytoplankton assemblages were observed along the estuary. In the upper segments, during the chlorophylla maximum fucoxanthin containing algae masked the other algal groups, which were relatively more abundant during or after enhanced river flows. In the lower estuary, although dominated by fucoxanthin-containing algae, the other algal groups were important all year around. In this study, the use of diagnostic pigments has provided considerable insight into the temporal and spatial dynamics of phytoplankton assemblages by detecting phytoplankton taxa generally underestimated or overlooked by microscopy.

Triplet states in photosystem I complexes from Synechococcus elongatus

Using Laser-flash induced transient absorption spectroscopy the dynamics of chlorophyll a (Chl) and carotenoid triplet states have been investigated in PS I complexes from Synechococcus elongatus. In the antenna, Chl triplet states arise from the lowest excited singlet state by intersystem crossing. They are efficiently quenched by triplet energy transfer to the carotenoids (Car). The triplet-triplet energy transfer from Chl to Car occurs with half-lives of » 10 ns (» 60%) and » 85 ns (» 40%). The kinetics and the efficiency of the triplet transfer have been analysed as a function of temperature. The Car triplet state decays with half-lives of » 3 µs at room temperature and » 7 µs at 80 K. In addition, triplet-minus-singlet absorption difference spectra of the carotenoids have been measured at 295 K and 78 K. In photosystem I, the maximum triplet absorption for the s-carotenes is observed at 528 nm. The triplet state of the primary electron donor, P700, is formed by charge recombination of the radical pair P700+A0-, when the electron transfer to A1 is blocked. The decay kinetics and the yield of 3P700 have been studied as a function of temperature. The decay rate increases with increasing temperature indicating an activation energy of about 40 meV. The results will be discussed in terms of the recent 2.5 A X-ray structure of photosystem I

SYNCHRONOUS BEHAVIOR OF TEMPERATURE, CALCIUM, AND CHLOROPHYLL IN LAKES OF NORTHERN WISCONSIN

The degree to which a variable's dynamics are synchronized among a set of neighboring lakes indicates the relative influence of regional climate variability. Furthermore, by determining which lakes tend to be most synchronous in their response to climate we can deduce the primary ways that climate influences the dynamics of the variable in question. In this study, we look for evidence of synchrony in the temperature, calcium, and chlorophyll dynamics of seven neighboring northern Wisconsin lakes. Our goals were to assess the influence of climate on dynamics of these variables and the effect of lake basin properties on their response to climate signals. Synchrony was measured as the r2 value from a regression relating observations of a variable in one lake against simultaneous observations of the same variable in another. Temperature was the most synchronous variable, with all pairs displaying significant synchrony. Calcium was also highly synchronous, with 15 of the 21 lake pairs exhibiting significant synchrony. Chlorophyll was significantly synchronous for 11 of the 21 lake pairs, but only three pairs exhibited r2 > 0.50. Lakes that were most similar in water clarity and average epilimnetic depth were most synchronous in temperature. Calcium was most synchronous among lakes occupying similar positions in the groundwater flow system, as expected from the control of calcium by groundwater flow paths. Synchrony of chlorophyll was highest for lakes with similar degrees of thermal stratification, suggesting that internal supplies of nutrients are an important determinant of interannual variability. The importance of ground- or bogwater flow to interannual chlorophyll dynamics is also suggested by the systematic asynchrony of chlorophyll for the clear-water lake that receives the least groundwater discharge. Our results show that climate imposes a strong synchrony on the behavior of three very different properties of the study lakes. Furthermore, the lakes differed predictably in their response to the same regional climate trends. Surprisingly, the differences between average synchrony observed for the three variables we considered were largely due to the diversity of the study lakes, rather than the disproportionate sensitivity of chlorophyll to local stochastic effects.

Assignment of the lowest Qy-state and spectral dynamics of the CP29 chlorophyll a/b antenna complex of green plants: a hole-burning study.

Low-temperature absorption, fluorescence and persistent non-photochemical hole-burned spectra are reported for the CP29 chlorophyll (Chl) a/b antenna complex of photosystem II of green plants. The absorption-origin band of the lowest Qy-state lies at 678.2 nm and carries a width of approximately 130 cm-1 that is dominated by inhomogeneous broadening at low temperatures. Its absorption intensity is equivalent to that of one of the six Chl a molecules of CP29. The absence of a significant satellite hole structure produced by hole burning, within the absorption band of the lowest state, indicates that the associated Chl a molecule is weakly coupled to the other Chl and, therefore, that the lowest-energy state is highly localized on a single Chl a molecule. The electron-phonon coupling of the 678.2 nm state is weak with a Huang-Rhys factor S of 0.5 and a peak phonon frequency (omega m) of approximately 20 cm-1. These values give a Stokes shift (2S omega m) in good agreement with the measured positions of the absorption band at 678.2 nm and a fluorescence-origin band at 679.1 nm. Zero-phonon holes associated with the lowest state have a width of approximately 0.05 cm-1 at 4.2 K, corresponding to a total effective dephasing time of approximately 400 ps. The temperature dependence of the zero-phonon holewidth indicates that this time constant is dominated at temperatures below 8 K by pure dephasing/spectral diffusion due to coupling of the optical transition to the glass-like two-level systems of the protein. Zero-phonon hole-widths obtained for the Chl b bands at 638.5 and 650.0 nm, at 4.2 K, lead to lower limits of 900 +/- 150 fs and 4.2 +/- 0.3 ps, respectively, for the Chl b-->Chl a energy-transfer times. Downward energy transfer from the Chl a state(s) at 665.0 nm occurs in 5.3 +/- 0.6 ps at 4.2 K.

Dynamics of ground and excited state chlorophylla molecules in pyridine solution probed by femtosecond transient absorption spectroscopy

Femtosecond pump–probe spectroscopy was used to investigate the ground and excited state dynamics of chlorophyll a (Chl a ) in pyridine following excitation by a 100 fs optical pulse. The transient absorption spectrum and kinetics reveal spectral evolution on two ultrafast time scales: ∼100 fs and ∼3 ps. We attribute these dynamics to ground-state transient hole-burning and solvation dynamics. Transient absorption anisotropy at early times (∼500 fs) was measured for Chl a in pyridine and shows a pronounced wavelength dependence, where anisotropy varies between 0 and 0.5. Strong contribution from excited state absorption is the origin of the variation.

Effective Shape and Dynamics of Chlorophyll a in a Nematic Liquid Crystal

The ordering matrix and the three rotational diffusion tensor components of chlorophyll a dissolved in the nematic liquid crystal ZLI-1167 have been determined at various temperatures employing a time-dependent fluorescence depolarization technique. The axis normal to the porphyrin ring is aligned on average perpendicular to the director and exhibits the slowest tumbling with respect to the director. The phytyl chain tends to be aligned with the director, and its overall spinning is the fastest.

Effects of grazer and substrate amendments on nutrient and plankton dynamics in estuarine enclosures

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 12:251-261 (1997) - doi:10.3354/ame012251 Effects of grazer and substrate amendments on nutrient and plankton dynamics in estuarine enclosures Miller CA, Glibert PM, Berg GM, Mulholland MR We compared the effects of substrate C:N ratio and macrozooplankton activity on nutrient and chlorophyll dynamics by amending the substrate C:N ratios in carboys containing natural estuarine microplankton (<200 μm) with additions of glucose (High C:N), arginine (Low C:N), or nothing (Control). Adult copepods (Acartia tonsa, 10 ind. l-1) were added to 1 carboy of each substrate treatment. Water and copepods were collected from the Choptank River, a subestuary of the Chesapeake Bay (USA) in August 1993. Ambient concentrations of NH4+, NO3-, and o-PO43- (orthophosphate) and dissolved primary amines (DPA) were all <2.0 μg-at. l-1. Dissolved and particulate nutrients and pigments were monitored over a 2 d period. In all carboys, plankton shifted from being net consumers of nutrients during the first 17 to 23 h (Phase 1) to being net regenerators afterwards (Phase 2). Chlorophyll concentrations declined and phaeopigments increased throughout the experiment. Both substrates stimulated microbial activity, as indicated by decreased accumulation of o-PO43- during Phase 2, increased accumulation of particulate carbon (PC) and nitrogen (PN) and increased chlorophyll loss during nighttime in the High C:N and Low C:N carboys relative to the Control carboy. In addition, the low C:N substrate resulted in increased accumulations of NH4+, NO2- and NO3-; increased chlorophyll concentration; and a day/night pattern in chlorophyll concentration. Copepod additions resulted in greater PC, PN and chlorophyll losses and day/night patterns in chlorophyll concentration. The additions of copepods and substrates together resulted in several interactive effects, most notably, increased accumulations of NH4+, o-PO43-, and, in the High C:N treatment, NO2-+NO3 -, and greater chlorophyll, PC, and PN losses. Estimated rates of ingestion and excretion by the added copepods could not account for the observed changes in chlorophyll and nutrients, especially in the carboys with copepod and substrate additions, suggesting that the copepods increased nutrient regeneration and phytoplankton removal by microzooplankton. Microbial loop · Substrate C:N ratios · Nutrient regeneration · Acartia tonsa · Chlorophyll dynamics Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 12, No. 3. Publication date: May 29, 1997 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 1997 Inter-Research.

Wind field effect on hydrography and chlorophyll dynamics in the coastal pelagial of Admiralty Bay, King George Island, Antarctica

The vertical distribution of physicochemical parameters and Chl a at a fixed station in Admiralty Bay (King George Island, South Shetland Islands) was recorded over 73 days during the summer of 1988/89. Temporal variations in Chl a and nutrient stocks in the euphotic zone were associated with changes in the wind/hydrological regime. Northerly winds of late December and early January moved the surface layers towards the outerbay, during which time the chlorophyll stocks remained low in the euphotic zone. Turbulence induced by southerly winds in the second half of January resuspended sediments and benthic diatoms in the shallow (0–20 m) inner inlets of the bay, increasing turbidity and nutrient concentrations at the surface. During the first half of February wind relaxation caused the mass sedimentation of previously resuspended benthic diatoms increasing chlorophyll and phaeopigments in the subsurface layers in deeper sections of the bay. Although turbulence limits phytoplankton biomass accumulation in open waters of the Antarctic, it may have a positive effect (increasing chlorophyll biomass of benthic origin) in coastal pelagic environments during late summer.

REVIEW OF A SEVENTEEN‐YEAR CHLOROPHYLL RECORD AS IT PERTAINS TO THE TROPIIIC STATUS OF LAKE OKEECHOBEE, FLORIDA, USA1

ABSTRACT: A 17‐year record of chlorophyll a at eight limnetic sampling stations was used to evaluate putative changes in the trophic status of Lake Okeechobee, a shallow polymictic lake located in the subtropical environment of South Florida. Significant spatial differences were observed in the temporal patterns and variability of chlorophyll a concentrations. The highest chlorophyll a values were found in the northern and northwestern regions of the lake. The center of the lake, subject to high levels of non‐algal suspended solids, exhibited relatively low chlorophyll a values and coefficient of variation. The lowest chlorophyll a values were observed at the southernmost sampling station in the lake. This was also the station that showed a significant upward trend in annual mean chlorophyll a values over the 17‐year period of record. Examination of the relationship between chlorophyll a and three key environmental variables (i.e., total phosphorus concentration, phosphorus loading, and lake stage) revealed significant correlations at two out of the eight stations. The overall results of this study indicate that spatial and temporal disparities in the distribution and dynamics of chlorophyll a in Lake Okeechobee mandate more temporally and spatially intense approaches to the evaluation of trophic state than used in previous studies.