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Complementary ship and satellite (Nimbus-7 - CZCS) bio-optical data from the Southern California Bight are being used to make a quantitative assessment of the chlorophyll concentration in these waters and its spatial and temporal variability.

Fluorometric determination of the chlorophyll content in natural lake populations can be determined by a new fluorometer. Its construction fulfills the requirements of limnological field experiments for high sensitivity, easy portability and ability to measure various photosynthetic parameters. Measurements are performed with the help of a special excitation mode and photosynthetic blocking with CMU. The measurements indicate the primary production of natural algal populations.

Our ability to study spatial structure in phytoplankton populations by the methods of spectral analysis depends on the development of a method for continuous measurement of chlorophyll concentration from a moving ship (Lorezen, 1966). Chlorophyll is used as the relative index of phytoplankton abundance, and it can be assayed continuously by Lorenzen’s in vivo fluorescence technique (see Platt and Denman, in press). Adaptation of this methodology to the particular requirement of phytoplankton patchiness research is discussed in Platt (1972) and in Herman and Denman (1977).

The loads and outflow of phosphorus and nitrogen in 1976 and 1977 are reported. Four expressions from the literature are used to estimate expected retention coefficients for phosphorus, and are compared with measured values, the ranges being 0.50-0.66 for the literature-based estimates and 0.47-0.68 for the measurements, the values for the latter being dependent on how much of the particulate nutrient load is included. Much of the nitrogen load appears to be lost to the atmosphere. Estimates are made of the effect that changes in sewage load will have on the annual mean phosphorus and chlorophyll concentration in the lake.

Ocean color study in Arabian sea is conducted with the obejective to establish primarily algorithm through which chlorophyll can be quantitatively determined. A method for atmospheric radiance calculation for evaluation of ocean chlorophyll concentration is developed. An algorithm relating reflectance to insitu chlorophyll pigment concentration is presented. A few chlorophyll pigment extraction models of other investigators are presented. Most of the models work well for those specific waters used to develop the algorithm.

When studying the links between the optical properties of a water body and its phytoplankton content, it is convenient to use and necessary to study the “chlorophyll-specific” absorption and scattering coefficients for algae, respectively, a ∗ and b ∗ is beginning to be well documented, little information is available on b ∗ and its possible variations from one species to another. This paper deals with the chlorophyll-specific scattering coefficient, and presents a simple theoretical treatment developed with a view to explaining the possible changes of b ∗ with the size of the algae cells and theor intracellular chlorophyll concentration. In spite of its simplified character, this approach accounts for the unexpectedly large variations in b ∗ , as observed for algae grown in culture. These predictions and results are compared to the b ∗ values derived for natural assemblages of phytoplankton in the marine environment.

A simple model of leaf optical properties spectra is derived from experimental measurements of leaf characteristics. It allows to simulate reflectance and transmittance spectra of the leaf depending on it’s chlorophyll concentration and leaf mesophyll structure.

Elevated metal concentrations in recent sediments indicate strongly that, during recent decades, heavy metal pollution of aquatic systems has increased practically all over the world. In spite of this, only a few cases of obviously adverse perturbations of aquatic populations have been reported. Nevertheless, it would be incorrect to conclude from this that widespread heavy metal pollution will be without effect on aquatic organisms. It must rather be assumed that changes in these ecosystems have evaded detection because of a lack of comparable unpolluted control systems or because such changes could not be related to increased heavy metal loadings for the reason that contamination with other substances changed simultaneously.

In the commercial development of herbicides during the past 25 years, a relatively few number of classes of chemical compounds have been introduced. Among these are derivatives of halogenated benzoic-, phenoxyalkyl acids, thiocarbamates, aminotriazole, and a series of photosynthesis inhibitors.

Chloroplasts isolated from Populus deltoides leaves were used to study age-dependent changes in the rate of cyclic photophosphorylation. Single leaves were used to measure CO(2) fixation by leaf discs, chlorophyll concentration, and ATP synthesis. The ability of chloroplasts to synthesize ATP diminished steadily from the time of full leaf expansion, regardless whether the results are expressed on a leaf area or chlorophyll basis. This decline in the rates of ATP synthesis was paralleled by the decline in the rate of CO(2) fixation. The results suggest that the efficiency of the membrane-bound ATP synthesizing system declines with age.

Treatment of Datura tatula with Amo-1618 increased the fresh and dry weights of the first-year plants, but decreased the alkaloid content. Maleic hydrazide (MH) treatment induced an increase in plant weight and total alkaloid content but a decrease in plant height. Second generation studies indicated a reduction of the fresh and dry weights of the Amo-1618 group, a considerable decrease in the alkaloid concentration of the MH group, and a decrease in the total alkaloid content of both groups. The chlorophyll concentration was not affected. A selective solvent extraction was performed on the leaf-tops. Gibberellin treatment of seeds obtained from plants previously treated with the chemicals generally reversed any inhibitory effect demonstrated by the chemicals on growth, alkaloid concentration and content, and the concentration of various selective-solvent fractions. Gibberellin seed treatment of the controls caused decreases in fresh weight, total alkaloid content, and the alcohol-soluble fractions of the plant.

Aims The Patagonian lakes are characterized by their oligotrophy that is the cause of low species number in their zooplankton assemblage. The aim of the present study is to analyze the crustacean and rotifers species number pattern in Patagonian lakes among a latitudinal gradient (40-51 °S). Results The results revealed that there are direct significant correlations between total species with rotifer species, and chlorophyll concentration with crustacean species number, and an inverse association between latitude with total species. Conclusion The results of co-occurrence species null model revealed presence of regulator factors in one of three simulations, that would be due to the presence of many species repeated in studied sites. Similar patterns were observed in Argentinean Patagonian lakes.

Information on the vertical chlorophyll structure in the ocean is important for estimating integrated chlorophyll a and primary production from satellite. For this study, vertical chlorophyll profiles from the Benguela upwelling system and the Angola-Benguela front were collected in winter to identify characteristic profiles. A shifted Gaussian model was fitted to each profile to estimate four parameters that defined the shape of the curve: the background chlorophyll concentration (B 0), the height parameter of the peak (h), the width of the peak (σ) and the depth of the chlorophyll peak (zm ). A type of artificial neural network called a self-organizing map (SOM) was then used on these four parameters to identify characteristic profiles. The analysis identified a continuum of chlorophyll patterns, from those with large surface peaks (>10 mg m−3) to those with smaller near-surface peaks (

The high phytoplankton production (PP) of the northern Gulf of California (NGC) supports a rich biodiversity and fisheries with high yields. The NGC is the habitat of the vaquita (Phocoena sinus), the cetacean most at risk of extinction in the world. The objective of this study is to demonstrate that the NGC is a healthy system at the level of primary producers despite the lack of nutrient input from the Colorado River, and that the small size of the vaquita population is not attributable the collapse of its pelagic ecosystem. Information derived from satellite sensors (CZCS, SeaWiFS, and Aqua-MODIS) was used to explore the possibility of a negative tendency in phytoplankton biomass and PP in the NGC during the last ~35 years. Temporal and spatial variations in sea surface temperature (SSTsat), chlorophyll concentration (Chlsat), and PP were analyzed. Times series were generated for four coastal quadrants, two in the western part and two in the eastern part of the NGC. The NW quadrant covers the vaquita habitat, and it had higher Chlsat and PP values than the others. This may be due to advection of turbid Upper Gulf waters into the NW quadrant. Semiannual and interannual changes in Chlsat and PP occurred, but the seasonal signal was dominant in the whole region. SSTsat maxima occurred in August and September (30–31 oC) and minima in January and February (16–17 oC). Chlsat and PP maxima were recorded in March and April (2–3 mg m–3, 2–3 g C m–2 day–1, respectively) and minima in August and September (0.2–0.9 mg m–3, 0.5–1.1 g C m–2 day–1, respectively). These values indicate that the pelagic ecosystem of the NGC is very productive (mesotrophic in summer-autumn and eutrophic in winter-spring). La alta produccion fitoplanctonica (PF) del norte del golfo de California (NGC) sustenta una gran biodiversidad y pesquerias con capturas elevadas. El NGC es el habitat de la vaquita (Phocoena sinus), el cetaceo que se encuentra en mayor peligro de extincion en el mundo. El objetivo de este estudio es demostrar que el NGC es un sistema sano en el ambito de los productores primarios a pesar de la falta del aporte de nutrientes del rio Colorado, y que el tamano pequeno de la poblacion de la vaquita no se debe al colapso de su ecosistema pelagico. Se utilizo informacion satelital (CZCS, SeaWiFS y Aqua-MODIS) con el proposito de explorar la posibilidad de una tendencia negativa de la biomasa y produccion fitoplanctonicas en el NGC en los ultimos ~35 anos. Se analizo la variacion espaciotemporal de la temperatura superficial del mar (TSMsat), la concentracion de clorofila (Chlsat) y PF. Se generaron series de tiempo para cuatro cuadrantes, dos en la parte occidental y dos en la parte oriental del NGC. El cuadrante noroccidental abarca el habitat de la vaquita y presento valores de Chlsat y PF mas altos que el resto de los cuadrantes. Esto puede deberse a la adveccion de aguas turbias del Alto Golfo hacia el cuadrante noroccidental. Se observaron cambios semianuales e interanuales de Chlsat y PF, pero los estacionales fueron dominantes en las cuatro localidades. Los maximos de TSMsat se registraron en agosto y septiembre (30–31 oC) y los minimos en enero y febrero (16–17 oC). Los maximos de Chlsat y PF se registraron en marzo y abril (2–3 mg m–3, 2–3 g C m–2 dia–1, respectivamente) y los minimos en agosto y septiembre (0.2–0.9 mg m–3, 0.5–1.1 g C m–2 dia–1, respectivamente). Estos valores de Chlsat y PF indican que el NGC es muy productivo (mesotrofico en verano-otono y eutrofico en inviernoprimavera).

Actively induced fluorescence techniques were investigated for their potential to detect differences in plant condition due to levels of nitrogen fertilization rate in field grown corn (Zea mays L.). Eight levels of N fertilization were applied representing treatments from over fertilization to under fertilization. Laboratory leaf fluorescence measurements were compared to laser induced fluorescence (LIF) canopy level "footprint" measurements. Fluorescence emission data were collected in the 360-800 nm region of the spectrum. Where there were no significant differences in chlorophyll concentration or corn grain yields, T test of fluorescence maxima from these regions indicated that plant growth condition due optimum levels of N fertilization could be separated from less efficient levels. Similar trends were observed with the leaf level and canopy level measures. >

Probable fishing grounds (PFG) of anchovy (Engraulis ringens) for the industrial purse seiner fleets in northern Chile (18/spl deg/21'-24/spl deg/S) are determined by sea surface temperature (SST) and thermal gradients (TGR) information estimated with NOAA AVHRR data and validated with in situ data. Using a Geographical Information System (GIS), relations between the catch per unit effort (CPUE) and surface environmental variables (SST and TGR) under a space-temporal approach are analyzed, with data available for the 1987-97 period. With this information and using the Bayesian theory approach and the fuzzy logic, an expert system (PFG model) is developed generating PFG charts. Chlorophyll concentration information has been collected for 1999, estimated with SeaWIFS data, which has allowed the first relations to be established between this variable and the CPUE distribution, which will be integrated into the PFG model. The results of the model are validated with information compiled during 1999.

A monstrous red tide appeared on October 2008 and expanded to the west on November 2008 off the Iranian coasts in the Hormuz Strait (east of the Persian Gulf). MODIS satellite data, hydrographic and bio-optical field measurements were used to detect the red tide. MODIS fluorescence line height (FLH in w m−2 μm−1 sr−1) data showed the highest correlation with near-concurrent in situ chlorophyll concentration of 0.74 (100(FLH))1.23 (r = 0.9, n = 44). In contrast, the band-ratio Chlorophyll product of MODIS showed more inconsistency with in situ chlorophyll data due to the interference of other water constituents. High FLH value patches >0.18 were confirmed to be located at the medium to high (104–106 cells l−1) concentrations of Cochlodinium polykrikoides, and also showed a chlorophyll anomaly >1 mg m−3, which means the potential of red tide occurrences. The FLH imagery also showed that the bloom started in early September along Bandar-Abbas port, and developed and moved to the west along the coastal region...

Two types of nondestructive chlorophyll meters were compared with a standard, destructive chlorophyll measurement technique. The nondestructive chlorophyll meters were 1) a custom built, single-wavelength meter, and 2) the recently introduced, dual-wavelength, chlorophyll meter from Minolta (model SPAD-502). Data from both meters were closely correlated with destructive measurements of chlorophyll (r2 = 0.90 and 0.93; respectively) for leaves with chlorophyll concentrations ranging from 100 to 600 mg·m-2, but both meters consistently overestimated chlorophyll outside this range. Although the dual-wavelength meter was slightly more accurate than the single-wavelength meter (higher r2), the light-scattering properties of leaf cells and the nonhomogeneous distribution of chlorophyll in leaves appear to limit the ability of all meters to estimate in vivo chlorophyll concentration.

An evaluation of Landsat Thematic Mapper (TM) data for the routine monitoring of surface chlorophyll concentration (C) and Secchi disk depth (SOD, a measure of the water clarity) used Cockburn Sound as a study area. Multi-temporal empirical algorithms to predict these parameters have been developedfrom the atmospherically-corrected satellite-received radiance and field data collected at the time of the satellite overpass. Highly significant, predictive algorithms for the surface C (range: 0·2–2·7 μg 1−1) and SOD (range: 4–15m) were obtained using bands I and 3 of the Thematic mapper. It is shown that a high confidence may be placed on the predictions using these algorithms and therefore it offers a cost-effective tool for complementing regular monitoring programmes.

The effects of leaf segment, leaf position on the plant, leaf age and photosynthetic photon flux density (PPFD) at the leaf surface were examined on leaf gas exchange of cv. Williams banana. All measurements were made on irrigated plants at the end of the dry season (September to November) over three years in Kununurra, WA, (Lat 16×S) a hot, arid region of North Western Australia. Net photosynthesis (Pn) did not differ between the segments on the leaf except when they received different PPFD. Pn reached a maximum of 20 to 25 μmol CO2 m–2s–1,9 d after the leaf had unrolled, that is when another new leaf had emerged and the measured leaf was in the second leaf position. Leaf chlorophyll concentration stabilized 7 d after unrolling but then increased slowly with time. The reduced rates of leaf gas exchange of older leaves are most likely a result of shading by younger leaves. The highest measured PPFD of 1800 (junol quanta m–2s–1 did not saturate Pn. Indeed, in a series of experiments, Pn measured at 1500 μmol quanta m–2s–1, was only 13 to 40% of the calculated maximum Pn at saturated values of PPFD, assuming Pn responds to PPFD in a hyperbolic function. In this study although Pn was lower in older leaves, the calculated internal CO2 concentration did not increase even at high leaf temperatures and leaf-to-air vapour pressure differences. Therefore, the photochemistry of the chloroplasts did not constrain Pn. To compare gas exchange measurements among experimental treatments, care is required as leaf position and environmental effects can greatly influence results. Our data suggest that differences in Pn between treatments should take account of PPFD, especially in this environment where the maximum PPFD measured did not saturate Pn of individual leaves.

Space-time variations in chlorophyll a (Chl a) concentrations in the surface water of upwelling regions along the Polish coast of the Baltic Sea were analysed. Carried out between 1998 and 2002 in the warmer season (from April till October), the measurements were targeted mainly at the Hel upwelling. Satellite-derived sea surface temperature (AVHRR) and Chl a data (SeaWiFS) were used. Generally speaking, the Chl a concentration increased in the upwelling plume, except along the Hel Peninsula, where two scenarios took place: a reduction in Chl a concentration in spring and an increase in autumn.

A major limitation in the calorimetry of sfresh broccoli has been the curvature of the head. Total chlorophyll concentration and visual appearance have thus been the methods of choice for color measurement. Samples from six cultivars selected for obvious visual color differences were presented to an older (Gardner C-4) and a newer (Gardner XL-845) generation calorimeter using both whole head and shaved floret sample presentations. No significant differences were observed in the total chlorophyll concentrations of the cultivars, but distinction was made among the cultivars using the shaved floret presentation for the older model and the whole head presentation for the newer model. Newer generation calorimeters thus provide a rapid nondestructive means of assessing fresh broccoli color.

IT has been claimed that polyvinyl alcohol (PVA) enhances both the growth and chlorophyll concentration of certain green algae and pea plants1–3. This effect of PVA on green algae has recently been questioned by Zuri and Mayer4, who were unable to confirm the earlier work. It is therefore appropriate to report briefly on some hitherto unpublished work relating to the effect of PVA on pea plants, which was carried out in this Laboratory shortly after the paper by Rejniak et al.2 was published.

SUMMARY (1) Seasonal variation in the leaf area index in grassland at Berhampur, India, showed a minimum of 0 5 in March and a maximum of 5.0 in late September. For most species, the maximum occurred between July and November. (2) There were seasonal changes in chlorophyll concentration, with maximum per unit dry weight of plant of 3 5 mg g-' in late August and maximum per unit area of 1.2 g m-2 in late September. Newbould (1967) and Milner & Hughes (1968) recommended that the estimation of chlorophyll concentration and leaf area indices should be utilized in all International Biological Programme projects as quantitative measures of the photosynthetic system. Although stems, petioles, leaf-sheaths and a few other green organs of plants show some light interception, which may be very important at certain times of the year, leaves are the main organs for photosynthesis and community production. Watson (1947) formulated the concept of leaf-area index (LAI) which is the quotient of the total leaf area (one surface only) divided by the total ground area. The community chlorophyll concentration per unit area was cited by Odum (1971) as an example of 'community homeostasis'. Several ecological processes, particularly (primary) production, are influenced by the amount of leaf area and the chlorophyll concentration (Brougham 1960; Bray 1960; Black 1963; Bliss 1966, 1970; Ovington & Lawrence 1967; Knight 1973; Mall & Billore 1974; Misra & Mall 1975; Billore & Mall 1975; Redmann 1975). This paper describes an attempt to evaluate the magnitude of the seasonal changes in LAI and chlorophyll concentration in terms of both dry weight of plant material and of ground area in a grassland community.

The changes in total nitrogen and chlorophyll concentration in barley infected by brown rust (Puccinia hordei Otth) during the course of the disease were investigated. In all the experiments the material used was the first foliage leaf of the seedling. In infected plants the chlorophyll concentration in the infected leaves decreases considerably 20 days after inoculation. On the other hand, the total nitrogen concentration, after a series of fluctuations, maintained a value more than twice that in the healthy leaf at the end of the experiments. Possible mechanisms explaining these phenomena are discussed.