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Several coastal embayments of eastern Georgian Bay show signs of water-quality impairment thought to be caused by human activities. Here, we evaluate the ability of the Lakeshore Capacity Model (LCM), developed for Precambrian Shield lakes, to assess the impact of cottage development on the trophic status of ten Georgian Bay embayments. The LCM could only be applied to eight embayments due to the large size and complexity of two watersheds and produced unacceptably high estimates of mean seasonal total phosphorus concentrations ([TP]; i.e., exceeded 20% of measured values for five of eight embayments); accuracy of [TP] estimates could not be improved by accounting for internal phosphorus loading. We developed an additional model, the Anthro-Geomorphic Model (AGM), which uses building density and basin morphometry as variables. Estimates of [TP] for the AGM were within 20% of measured values for all sites. Compared with other aquatic systems, coastal embayments of Georgian Bay have significantly higher chlorophyll a concentrations per unit [TP]; we suggest that the TP-chlorophyll relationship presented in this study be used to estimate productivity in these systems. Plusieurs echancrures de la partie est de la baie Georgienne presentent des indices de degradation de la qualite de l'eau qui serait causee par l'activite humaine. Nous examinons la capacite du modele devaluation de la capacite d'amenagement des rives (<>, LCM), mis au point pour les lacs du bouclier precambrien, d'evaluer l'impact de l'amenagement de chalets sur l'etat trophique de dix echancrures de la baie Georgienne. Le LCM n'a pu etre applique qu'a huit echancrures en raison de la grande taille et de la complexite de deux bassins versants, et il a produit des estimations trop elevees, voire inacceptables des concentrations saisonnieres moyennes de phosphore total ([PT]) (de 20% superieures aux valeurs mesurees pour cinq echancrures sur huit), l'integration de la charge interne de phosphore ne permettant pas d'accroitre l'exactitude de ces estimations. Nous avons developpe un autre modele, le modele <> (MAG), qui utilise la densite d'immeubles et la morphometrie du bassin comme variables. Les estimations du [PT] par le MAG ne different pas de plus de 20% des valeurs mesurees pour tous les sites. Comparativement a d'autres systemes aquatiques, les echancrures des cotes de la baie Georgienne presentent des concentrations de chlorophylle a par unite de [PT] significativement plus elevees. Nous proposons que la relation entre le PT et la chlorophylle presentee dans l'etude soit utilisee pour estimer la productivite dans ces systemes. [Traduit par la Redaction], Introduction Georgian Bay, the eastern arm of Lake Huron, is the largest bay in the Laurentian Great Lakes, with a maximum depth of 171 m (McCarthy and McAndrews 2012) and [...]

ABSTRACT. In this study, we support previous work showing that a normalized difference index (NDI) using two spectral bands of transmitted irradiance (478 and 490 nm) can be used as [...]

This paper examines the use of simulated and measured canopy reflectance for chlorophyll estimation over crop canopies. Field spectral measurements were collected over corn and wheat canopies in different intensive field campaigns organized during the growing seasons of 2004 and 2005. They were used to test and evaluate several combined indices for chlorophyll determination using hyperspectral imagery (Compact Airborne Spectrographic Imager). Several index combinations were investigated using both PROSPECT-SAILH canopy simulated spectra and field-measured reflectances. The relationships between leaf chlorophyll content and combined optical indices have shown similar trends for both PROSPECT-SAILH simulated data and ground-measured data sets, which indicates that both spectral measurements and radiative transfer models hold comparable potential for the quantitative retrieval of crop foliar pigments. The data set used has shown that crop type had a clear influence on the establishment of predictive equations as well as on their validation. In addition to generating different predictive equations, corn and wheat data yielded contrasting agreement between estimated and measured chlorophyll contents even for the same predictive algorithm. Among the set of indices tested in this paper, index combinations like Modified Chlorophyll Absorption Ratio Index/ Optimized Soil-Adjusted Vegetation Index (OSAVI), Triangular Chlorophyll Index/OSAVI, Moderate Resolution Imaging Spectrometer Terrestrial Chlorophyll Index/Improved Soil-Adjusted Vegetation Index (MSAVI), and Red-Edge Model/MSAVI seem to be relatively consistent and more stable as estimators of crop chlorophyll content. Index Terms--Chlorophyll content, chlorophyll estimation, combined indices, crop-type effect, hyperspectral, leaf area index (LAI), precision agriculture.

The extent and type of vegetation within watersheds are critical factors influencing stream water chemistry, specifically nitrogen and phosphorus concentrations. As stream productivity can be limited by nutrient supply, nutrient subsidies from red alder, a nitrogen fixing species prevalent in the Pacific Northwest of North America and other temperate climates, may influence the degree of nutrient limitation in streams. Our study was designed to determine the extent that algae are nutrient limited in three red alder and three coniferous forested second and third-order streams on the Olympic Peninsula, Washington, U.S.A. Nutrient diffusing substrates were used in each stream to test whether nitrogen and phosphorus additions at three concentrations (0.05 M, 0.1 M and 0.5 M) increased chlorophyll a concentrations compared to non-nutrient infused substrates. With the addition of nitrogen or phosphorus, three of six streams (two conifer and one alder stream) had significantly higher chlorophyll a concentrations relative to controls. Within each stream, we saw no difference in chlorophyll a concentrations between nutrient type (nitrogen or phosphorus) or concentration (0.05 M, 0.10 M or 0.50 M). Treatments increased chlorophyll a concentrations in alder streams to twice that of conifer streams. We speculate that other factors, such as algae community composition, contributed to differing algae production in alder and conifer streams in response to nutrient supplements.

Determining mechanisms associated with heat tolerance and identifying screening methods are vital for improvement of heat tolerance in plants. The objectives of this study were to investigate the relationship between the heat stability of thylakoids and loss of chlorophyll in winter wheat (Triticum aestivum L.) under heat stress, and to examine whether chlorophyll loss can be used as an indicator of heat tolerance in wheat. We assessed heat tolerance and measured chlorophyll content in 12 cultivars of winter wheat at flowering stage during exposure to 16-d-long heat stress. Heat tolerance was assessed using fluorescence to determine the heat stability of thylakoids, and chlorophyll content was measured with a chlorophyll meter. Experiments were conducted under controlled conditions. Heat stress caused damage to thylakoids in all cultivars as indicated by the increase in the ratio of constant fluorescence (O) and the peak of variable fluorescence (P). Heat stress also caused a decline in chlorophyll content in most cultivars. A strong negative correlation between heat-induced increases in O/P and chlorophyll content was seen. The results suggest that heat-induced damage to thylakoids and chlorophyll loss are closely associated in winter wheat. Measurements of chlorophyll content with a chlorophyll meter could be useful for high throughput screening for heat tolerance in wheat.

A methodology is presented for retrieving phytoplankton chlorophyll-a concentration from space. The data to be inverted, namely, vectors of top-of-atmosphere reflectance in the solar spectrum, are treated as explanatory variables conditioned by angular geometry. This approach leads to a continuum of inverse problems, i.e., a collection of similar inverse problems continuously indexed by the angular variables. The resolution of the continuum of inverse problems is studied from the least-squares viewpoint and yields a solution expressed as a function field over the set of permitted values for the angular variables, i.e., a map defined on that set and valued in a subspace of a function space. The function fields of interest, for reasons of approximation theory, are those valued in nested sequences of subspaces, such as ridge function approximation spaces, the union of which is dense. Ridge function fields constructed on synthetic yet realistic data for case I waters handle well situations of both weakly and strongly absorbing aerosols, and they are robust to noise, showing improvement in accuracy compared with classic inversion techniques. The methodology is applied to actual imagery from the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS); noise in the data are taken into account. The chlorophyll-a concentration obtained with the function field methodology differs from that obtained by use of the standard SeaWiFS algorithm by 15.7% on average. The results empirically validate the underlying hypothesis that the inversion is solved in a least-squares sense. They also show that large levels of noise can be managed if the noise distribution is known or estimated. OCIS codes: 280.0280, 010.0010.

In the upper layer of the global ocean, 2082 in situ chlorophyll biomass values are retrieved by concurrent satellite-derived inherent optical properties (IOP). It is found that (1) the phytoplankton absorption coefficient IOP alone does not provide satisfactory retrieval; (2) the chromophoric dissolved organic matter (CDOM) absorption coefficient IOP must also be used to obtain satisfactory retrieval through [varies] [a.sub.ph] + [pa.sub.CDOM] where p is a constant and [a.sub.ph] and [a.sub.CDOM] are, respectively, the phytoplankton and CDOM absorption coefficients; (3) the IOP-based retrieval performance is comparable to standard satellite reflectance ratio retrievals (that have CDOM absorption intrinsically embedded within them); (4) inclusion of the total backscattering coefficient IOP does not contribute significantly to retrieval; and (5) the new IOP-based algorithm may provide the possibility for future research to establish the actual role of extracellular CDOM from all sources in the intracellular production of chlorophyll biomass. OCIS codes: 010.4450, 280.0280, 300.6550.

Byline: Dong-Hoon Han (1), Tohru Ikeya (1), Masayuki Mac Takahashi (1) Keywords: Netplankton; chlorophyll a; Pacific Ocean; euphotic zone; subsurface chlorophyll maximum; equatorial upwelling; El Nino Abstract: An analysis is presented of data on chlorophyll a concentrations of the total and the netplankton (&gt 10 um), determined either in April to June or in August to September from 48degN to 15degS along 175degE in the Pacific Ocean during 6 years by the NOPACCS (Northwest Pacific Carbon Cycle Study). Particular attention was given to the variability of absolute concentrations of the netplankton chlorophyll a and their percentage shares of the total chlorophyll a concentration. Below 0.2 ug l.sup.-1 of surface total chlorophyll a, the netplankton chlorophyll a showed low percentage shares (such as 12.7% on average) with a large variation, but above 0.2 ug l.sup.-1 it was 35.9% on average with less variation, showing an accelerated increase at high total chlorophyll a concentrations. High netplankton chlorophyll a concentrations in surface waters were observed at high latitudes, in waters having high chlorophyll a concentrations at sub-surface depth, and in equatorial upwelling. The percentage shares of netplankton in the total chlorophyll a in the euphotic zone were 8.5% and 25.9% above and below 0.2 ug l.sup.-1, respectively, although the data points scattered over a wide range (from 7.2% to 53.8%) depending on differences in water masses, depths and seasons. High chlorophyll a concentrations and high percentage shares of netplankton corresponded to high ambient nitrate plus nitrite concentrations. Integrated netplankton chlorophyll a concentrations in the euphotic zone varied from 0.7 to 19.5 mg m.sup.-2 in waters below 0.2 ug l.sup.-1 of surface total chlorophyll a, and from 2.0 to 29.5 mg m.sup.-2 above 0.2 ug l.sup.-1, and the percentage shares of netplankton for the former were 7.4% on average and 23.7% for the latter. Author Affiliation: (1) Department of Systems Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan Article History: Registration Date: 17/09/2004

The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft contains spectral bands that allow retrieval of solar-induced phytoplankton chlorophyll fluorescence emission radiance. Concurrent airborne laser-induced (and water-Raman normalized) phytoplankton chlorophyll fluorescence data is used to successfully validate the MODIS chlorophyll fluorescence line height (FLH) retrievals within Gulf Stream, continental slope, shelf, and coastal waters of the Middle Atlantic Bight portion of the western North Atlantic Ocean for 11 March 2002. Over the entire ~480-km flight line a correlation coefficient of [r.sup.2] = 0.85 results from regression of the airborne laser data against the MODIS FLH. It is also shown that the MODIS FLH product is not influenced by blue-absorbing chromophoric dissolved organic matter absorption. These regional results strongly suggest that the FLH methodology is equally valid within similar oceanic provinces of the global oceans. OCIS codes: 010.4450, 120.0280, 280.3640, 280.3420, 300.2530, 300.6360.

The development of a deep chlorophyll maximum (DCM) at a depth of 30-35 m was followed during a 15-d case study in July 1998 at the entrance to the Gulf of Finland. The study consisted of three 18-24-h periods of biological (chlorophyll a, phytoplankton, primary production), chemical (nitrate, phosphate) and physical (CTD, turbulence, vertical particle size distribution) measurements at an anchor station and six mesoscale towed CTD/ fluorometer mappings over the surrounding area. Exceptionally cold and windy weather led to a red tide of the dinoflagellate Heterocapsa triquetra instead of the cyanobacterial bloom that frequently occurs in late summer. Comparison of the estimated amount of nitrogen required for an H. triquetra bloom biomass with external loading affirmed that the bloom had been formed on the basis of the nitrate pool below the thermocline. The development of the bloom, therefore, led to the extremely deep nitracline. The DCM formed by H. triquetra developed at the top of the nitracline at an illumination of

A new algorithm has been developed for simultaneous retrieval of aerosol optical properties and chlorophyll concentrations in case I waters. This algorithm is based on an improved complete model for the inherent optical properties and accurate simulations of the radiative transfer process in the coupled atmosphere--ocean system. It has been tested against synthetic radiances generated for the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) channels and has been shown to be robust and accurate. A unique feature of this algorithm is that it uses the measured radiances in both near-IR and visible channels to find that combination of chlorophyll concentration and aerosol optical properties that minimizes the error across the spectrum. Thus the error in the retrieved quantities can be quantified. OCIS codes: 010.0010, 280.0280, 010.1110, 010.4450.

The performance of the OC2 Sea-viewing Wide Field-of-view Sensor (SeaWiFS) algorithm based on 490-and 555-nm water-leaving radiances at low chlorophyll contents is compared with those of semianalytical models and a Monte Carlo radiative transfer model. We introduce our model, which uses two particle phase functions and scattering coefficient parameterizations to achieve a backscattering ratio that varies with chlorophyll concentration. We discuss the various parameterizations and compare them with existent measurements. The SeaWiFS algorithm could be confirmed within an accuracy of 35% over a chlorophyll range from 0.1 to 1 mg [m.sup.-3], whereas for lower chlorophyll concentrations we found a significant overestimation of the OC2 algorithm. OCIS codes: 010.0010, 010.4450, 290.1350, 290.5850.

The estimation of chlorophyll concentration in the water by use of a field spectroradiometer above the water surface is necessary for the removal of the effect of specular reflection at the water surface. The amount of specular reflection from the water surface was assessed on the basis of the spectral signature data that was measured above and below the water surface. Furthermore, a method to remove the effect of specular reflection from spectral signature data that was measured above water surface was proposed. Finally, chlorophyll-a concentration was estimated accurately from the spectral signature measured by field spectroradiometer above water surface with the proposed surface reflection model. OCIS codes: 010.7340, 070.4790, 350.4600.

Satellite observations of global ocean chlorophyll span more than two decades. However, incompatibilities between processing algorithms prevent us from quantifying natural variability. We applied a comprehensive reanalysis to the Coastal Zone Color Scanner (CZCS) archive, called the National Oceanic i and Atmospheric Administration and National Aeronautics and Space Administration (NOAA-NASA) CZCS reanalysis (NCR) effort. NCR consisted of (1) algorithm improvement (AI), where CZCS processing algorithms were improved with modernized atmospheric correction and bio-optical algorithms and (2) blending where in situ data were incorporated into the CZCS AI to minimize residual errors. Global spatial and seasonal patterns of NCR chlorophyll indicated remarkable correspondence with modern sensors, suggesting compatibility. The NCR permits quantitative analyses of interannual and interdecadal trends in global ocean chlorophyll. OCIS codes: 010.4450, 010.1290, 280.0280.

A compact helicopter-based lidar system is developed and tested under laboratory and field conditions. It is shown that the lidar can measure concentrations of chlorophyll a and dissolved organic matter at the surface of water bodies, detect fluorescence spectra of ground vegetation at a distance of up to 530 m, and determine the vertical profile of light-scattering particle concentration in the upper ocean. The possibilities of the lidar system are demonstrated by detection of polluted areas at the ocean surface, by online monitoring of three-dimensional distribution of light-scattering layers, and by recognition of plant types and physiological states. OCIS codes: 010.0010, 010.3640, 010.7340.

Research indicates a strong annual periodicity for photosynthetic processes in the Atlantic Ocean near Bermuda. Chlorophyll, mixing depth and temperature demonstrated the highest correlations with potential forcing and photosynthetic performance.

Findings are presented on phytoplankton populations in the Pacific Ocean's Equatorial region. These include the consistency of chlorophyl ratios across algal class categories, with light-harvesting pigments increasing with depth and photoprotective pigments decreasing with depth.

Data taken during three consecutive summers indicate that the Atlantic Ocean possesses a comparatively consistent oceanographic structure. Findings include two regions of high phytoplankton production with an accompanying high chlorophyll count near Antarctica and Brazil, while the remaining zones demonstrate low chlorophyll counts.

Research indicates that the Bay of Bengal contains a two-gyre circulation system, one cyclonic and the other anticyclonic. The chlorophyll maximum was found to be almost twice as high in the cyclonic region than in the anticyclonic region, although its depth is larger in the anticyclonic region.

Byline: Thomas J. Mangos (1), R. G. Berger (2) Keywords: Spinach (Spinacia oleracea); Chlorophyll; Degradation; HPLC Abstract: An HPLC procedure is described which enables both identification and quantitation of chlorophyll a and chlorophyll b and their major degradation products which can occur during solvent extraction of chloropigments from green plant leaves or during storage and canning of green vegetables. The method has been applied to visualize enzymatic as well as chemical degradation of chloropigments from spinach. Complex mixtures of phytyl esters of chlorophyllides, pheophorbides, pyrochlorophyllides, and pyropheophorbides and their respective hydrolysis products were separated, identified and quantitated in the presence of carotenoids in a process lasting less than 40amin. Author Affiliation: (1) United States Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA, US (2) Institut fur Lebensmittelchemie, Universitat Hannover,Wunstorfer Strasse 14, D-30453 Hannover, Germany, DE Article note: Received: 2 August 1996

The physical and biological variables, and their distribution in the Gulf stream meander crest have similar patterns. Principal Component Analysis of density, zooplankton biomass, chlorophyll a and salinity are conducted in relation to the cross-sectional average of the variables. The eastern part of the crest and area north of the current axis have Slope Water like features. The region to the west of the crest has low levels of zooplankton biomass and chlorophyll. The distribution pattern of the variables is due to processes such as cross stream advection, and meander upwelling and downwelling.

The physical features of the North Atlantic subtropical region southeast of Azores determine the presence of high biomass in that region. This region consists of the subtropical front (STF) and Azores Current (AC), and the STF-AC region has high biomass concentration. The chlorophyll a distribution in the STF-AC region is two to three times more than that in the frontal boundary or what is predicted by basin-scale models. The occurrence of high chlorophyll a in this region is due to surface outcrop of the front and passive accumulation of phytoplanktons at the frontal boundary.

An underwater optical serial-sectioning technique is developed to measure in situ three-dimensional distributions of biological particles. The technique involves scanning of a thin plane of laser light through a range of distances parallel to the imaging plane of a digital CCD camera. Images of induced fluorescence in the sequentially illuminated planes are recorded. An inverse method is then used to reconstruct three-dimensional chlorophyll a distributions from the plane images. Computer simulations of the image formation and reconstruction process indicate that the underwater optical serial-sectioning technique is practical for in situ determination and analysis of chlorophyll a microstructures for concentrations as low as 0.1 mg of chlorophyll a per cubic meter in 1-m cubed water volumes.

Seasonal patterns in surface chlorophyll derived from Coastal Zone Color Scanner data for the North Atlantic Ocean from 1979 to 1983 were used to estimate new production. The technique was based on the assumption that when chlorophyll is increasing, there is excess nitrate available, and when chlorophyll declines during a bloom, nitrate depletion occurs. Estimates of the rate of the deepening of the nitracline combined with the timing of nitrogen availability and depletion as revealed by satellite-derived surface chlorophyll data could be a useful indictor of new production.