Seasonality, phytoplankton succession and the biogeochemical impacts of an autumn storm in the northeast Atlantic Ocean

NASA Astrophysics Data System (ADS)

Painter, Stuart C.; Finlay, Madelaine; Hemsley, Victoria S.; Martin, Adrian P.

2016-03-01

Phytoplankton chemotaxonomic distributions are examined in conjunction with taxon specific particulate biomass concentrations and phytoplankton abundances to investigate the biogeochemical consequences of the passage of an autumn storm in the northeast Atlantic Ocean. Chemotaxonomy indicated that the phytoplankton community was dominated by nanoplankton (2-20 μm), which on average represented 75 ± 8% of the community. Microplankton (20-200 μm) and picoplankton (<2 μm) represented 21 ± 7% and 4 ± 3% respectively with the microplankton group composed of almost equal proportions of diatoms (53 ± 17%) and dinoflagellates (47 ± 17%). Total chlorophyll-a (TCHLa = CHLa + Divinyl CHLa) concentrations ranged from 22 to 677 ng L-1, with DvCHLa making minor contributions of between <1% and 13% to TCHLa. Higher DvCHLa contributions were seen during the storm, which deepened the surface mixed layer, increased mixed layer nutrient concentrations and vertically mixed the phytoplankton community leading to a post-storm increase in surface chlorophyll concentrations. Picoplankton were rapid initial respondents to the changing conditions with pigment markers showing an abrupt 4-fold increase in proportion but this increase was not sustained post-storm. 19‧-HEX, a chemotaxonomic marker for prymnesiophytes, was the dominant accessory pigment pre- and post-storm with concentrations of 48-435 ng L-1, and represented 44% of total carotenoid concentrations. Accompanying scanning electron microscopy results support the pigment-based analysis but also provide detailed insight into the nano- and microplankton communities, which proved to be highly variable between pre-storm and post-storm sampling periods. Nanoplankton remained the dominant size class pre- and post-storm but the microplankton proportion peaked during the period of maximum nutrient and chlorophyll concentrations. Classic descriptions of autumn blooms resulting from storm driven eutrophication events promoting phytoplankton growth in surface waters should be tempered with greater understanding of the role of storm driven vertical reorganization of the water column and of resident phytoplankton communities. Crucially, in this case we observed no change in integrated chlorophyll, particulate organic carbon or biogenic silica concentrations despite also observing a ∼50% increase in surface chlorophyll concentrations which indicated that the surface enhancement in chlorophyll concentrations was most likely fed from below rather than resulting from in situ growth. Though not measured directly there was no evidence of enhanced export fluxes associated with this storm. These observations have implications for the growing practice of using chlorophyll fluorescence from remote platforms to determine ocean productivity late in the annual productivity period and in response to storm mixing.

Environmental studies of the Arabian Sea using remote sensing and GIS

NASA Astrophysics Data System (ADS)

Saxena, Ashlesha; Menezes, Andrew

2006-12-01

The Arabian Sea, situated in the western part of the northern Indian Ocean is a tropical basin. It is bounded on the east by the Indian peninsula, on the north by Baluchistan and Sindh provinces of Pakistan and on the west by the landmass of Arabia and Africa. The environmental factors that influence this tropical basin are the seasonally changing winds from the northeast during winter (November-February) and southwest during summer (June to September). Accordingly, the waters of the basin will experience seasonal variations. The study aims at understanding the seasonal and inter-annual variation of the Arabian Sea using satellite-derived data. The spatial domain selected for the present study is 40 degrees E and 78 degrees E longitude and equator to 30 degrees N. The remote sensing data with respect to sea surface temperature (SST), sea surface wind, sea surface height (SSH), and chlorophyll pigment concentration during January 2002 to December 2005 were used to understand the spatio-temporal variability of the Arabian Sea. The monthly mean SST data was obtained from Modis aqua, winds from Quikscat and chlorophyll pigment concentration from SeaWiFS. The SSH anomaly data was obtained from the merged product - Topex/Poseidon ERS 1/2 satellite which is 7-day snapshot. The spatial resolution of these data is 0.3 degrees latitude x 0.3 degrees longitude. Geographical information system (GIS) was used for processing and analysing the above parameters to determine the variability and detection of oceanic processes that are responsible for such variability.The study showed a very strong inverse correlation between SST and chlorophyll concentrations. Arabian Sea undergoes cooling during summer due to upwelling and advection, and in winter due to surface cooling under reduced solar heating. Upwelling along the coasts of Somalia, Arabia, and the west coast of India brings cold and nutrient rich sub-surface waters to the surface, which supports the observed high chlorophyll concentrations. During winter the convective mixing in the northern Arabian Sea supports high chlorophyll pigment concentrations. Due to strong solar heating, SST was warmest in spring (April), which supported least chlorophyll concentration.llite

Detecting chlorophyll, Secchi disk depth and surface temperature in a sub-alpine lake using Landsat imagery.

PubMed

Giardino, C; Pepe, M; Brivio, P A; Ghezzi, P; Zilioli, E

2001-03-14

Some bio-physical parameters, such as chlorophyll a concentration, Secchi disk depth and water surface temperature were mapped in the sub-alpine Lake Iseo (Italy) using Landsat Thematic Mapper (TM) data acquired on the 7 March 1997. In order to adequately investigate the water-leaving radiance, TM data were atmospherically corrected using a partially image-based method, and the atmospheric transmittance was measured in synchrony with the satellite passage. An empirical approach of relating atmospherically corrected TM spectral reflectance values to in situ measurements, collected during the satellite data acquisition, was used. The models developed were used to map the chlorophyll concentration and Secchi disk depth throughout the lake. Both models gave high determination coefficients (R2 = 0.99 for chlorophyll and R2 = 0.85 for the Secchi disk) and the spatial distribution of chlorophyll concentration and Secchi disk depth was mapped with contour intervals of 1 mg/m3 and 1 m, respectively. A scene-independent procedure was used to derive the surface temperature of the lake from the TM data with a root mean square error of 0.3 degrees C.

Chlorophyll-a concentration estimation with three bio-optical algorithms: correction for the low concentration range for the Yiam Reservoir, Korea

USDA-ARS?s Scientific Manuscript database

Bio-optical algorithms have been applied to monitor water quality in surface water systems. Empirical algorithms, such as Ritchie (2008), Gons (2008), and Gilerson (2010), have been applied to estimate the chlorophyll-a (chl-a) concentrations. However, the performance of each algorithm severely degr...

Optimalisation of remote sensing algorithm in mapping of chlorophyl-a concentration at Pasuruan coastal based on surface reflectance images of Aqua Modis

NASA Astrophysics Data System (ADS)

Wibisana, H.; Zainab, S.; Dara K., A.

2018-01-01

Chlorophyll-a is one of the parameters used to detect the presence of fish populations, as well as one of the parameters to state the quality of a water. Research on chlorophyll concentrations has been extensively investigated as well as with chlorophyll-a mapping using remote sensing satellites. Mapping of chlorophyll concentration is used to obtain an optimal picture of the condition of waters that is often used as a fishing area by the fishermen. The role of remote sensing is a technological breakthrough in broadly monitoring the condition of waters. And in the process to get a complete picture of the aquatic conditions it would be used an algorithm that can provide an image of the concentration of chlorophyll at certain points scattered in the research area of capture fisheries. Remote sensing algorithms have been widely used by researchers to detect the presence of chlorophyll content, where the channels corresponding to the mapping of chlorophyll -concentrations from Landsat 8 images are canals 4, 3 and 2. With multiple channels from Landsat-8 satellite imagery used for chlorophyll detection, optimum algorithmic search can be formulated to obtain maximum results of chlorophyll-a concentration in the research area. From the calculation of remote sensing algorithm hence can be known the suitable algorithm for condition at coast of Pasuruan, where green channel give good enough correlation equal to R2 = 0,853 with algorithm for Chlorophyll-a (mg / m3) = 0,093 (R (-0) Red - 3,7049, from this result it can be concluded that there is a good correlation of the green channel that can illustrate the concentration of chlorophyll scattered along the coast of Pasuruan

THE SPATIAL DISTRIBUTION OF PHYTOPLANKTON CHLOROPHYLL CONCENTRATIONS IN NARRAGANSETT BAY USING AIRCRAFT REMOTE SENSING

EPA Science Inventory

During the summer of 2002, phytoplankton chlorophyll concentrations were determined in Narragansett Bay, Rhode Island using a light aircraft equipped with the MicroSAS remote sensing system. From an altitude of 300 m, the three sensor system measured sea surface radiance (Lt), sk...

Multispectral In-situ Measurements of Organic Matter and Chlorophyll Fluorescence in Seawater: Documenting the Intrusion of the Mississippi River Plume in the West Florida Shelf

NASA Technical Reports Server (NTRS)

DelCastillo, Carlos E.; Coble, Paula G.; Conmy, Robyn N.; Mueller-Karger, Frank E.; Vanderbloomen, Lisa; Vargo, Gabriel A.

2000-01-01

We performed multispectral in-situ fluorescence measurement of colored dissolved organic matter and chlorophyll in surface water of the West Florida Shelf using West Labs Spectral absorption and Fluorescence Instrument (SAFIre). Continuous measurements underway allowed us to simultaneously map the dispersion of riverine organic material and chlorophyll on the shelf. By using two fluorescence emission ratios we were able to differentiate between riverine and marine CDOM. Our data also showed unusually high concentrations of CDOM offshore. These were attributed to an intrusion of the Mississippi River Plume. We performed limited comparisons between in-situ chlorophyll concentrations measured with SAFIre and chlorophyll values obtained from SeaWiFS satellite data using OC4 and MODIS algorithm. Our results show that, although both algorithms overestimated chlorophyll, MODIS performed better than OC4, particularly in areas with high CDOM concentrations. Analysis of the relationship between chlorophyll and CDOM concentrations within the study area showed regional variability causes by differences in river source.

Remote sensing of chlorophyll and temperature in marine and fresh waters.

NASA Technical Reports Server (NTRS)

Arvesen, J. C.; Millard, J. P.; Weaver, E. C.

1973-01-01

An airborne differential radiometer was demonstrated to be a sensitive, real-time detector of surface chlorophyll content in water bodies. The instrument continuously measures the difference in radiance between two wavelength bands, one centered near the maximum of the blue chlorophyll a absorption region and the other at a reference wavelength outside this region. Flights were made over fresh water lakes, marine waters, and an estuary, and the results were compared with 'ground truth' measurements of chlorophyll concentration. A correlation between output signal of the differential radiometer and the chlorophyll concentration was obtained. Examples of flight data are illustrated. Simultaneous airborne measurements of chlorophyll content and water temperature revealed that variations in chlorophyll are often associated with changes in temperature. Thus, simultaneous sensing of chlorophyll and temperature provides useful information for studies of marine food production, water pollution, and physical processes such as upwelling.

Sensitivity of airborne fluorosensor measurements to linear vertical gradients in chlorophyll concentration

NASA Technical Reports Server (NTRS)

Venable, D. D.; Punjabi, A. R.; Poole, L. R.

1984-01-01

A semianalytic Monte Carlo radiative transfer simulation model for airborne laser fluorosensors has been extended to investigate the effects of inhomogeneities in the vertical distribution of phytoplankton concentrations in clear seawater. Simulation results for linearly varying step concentrations of chlorophyll are presented. The results indicate that statistically significant differences can be seen under certain conditions in the water Raman-normalized fluorescence signals between nonhomogeneous and homogeneous cases. A statistical test has been used to establish ranges of surface concentrations and/or verticl gradients in which calibration by surface samples would by inappropriate, and the results are discussed.

Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide

PubMed Central

Wernand, Marcel R.; van der Woerd, Hendrik J.; Gieskes, Winfried W. C.

2013-01-01

Marine primary productivity is an important agent in the global cycling of carbon dioxide, a major ‘greenhouse gas’, and variations in the concentration of the ocean's phytoplankton biomass can therefore explain trends in the global carbon budget. Since the launch of satellite-mounted sensors globe-wide monitoring of chlorophyll, a phytoplankton biomass proxy, became feasible. Just as satellites, the Forel-Ule (FU) scale record (a hardly explored database of ocean colour) has covered all seas and oceans – but already since 1889. We provide evidence that changes of ocean surface chlorophyll can be reconstructed with confidence from this record. The EcoLight radiative transfer numerical model indicates that the FU index is closely related to chlorophyll concentrations in open ocean regions. The most complete FU record is that of the North Atlantic in terms of coverage over space and in time; this dataset has been used to test the validity of colour changes that can be translated to chlorophyll. The FU and FU-derived chlorophyll data were analysed for monotonously increasing or decreasing trends with the non-parametric Mann-Kendall test, a method to establish the presence of a consistent trend. Our analysis has not revealed a globe-wide trend of increase or decrease in chlorophyll concentration during the past century; ocean regions have apparently responded differentially to changes in meteorological, hydrological and biological conditions at the surface, including potential long-term trends related to global warming. Since 1889, chlorophyll concentrations have decreased in the Indian Ocean and in the Pacific; increased in the Atlantic Ocean, the Mediterranean, the Chinese Sea, and in the seas west and north-west of Japan. This suggests that explanations of chlorophyll changes over long periods should focus on hydrographical and biological characteristics typical of single ocean regions, not on those of ‘the’ ocean. PMID:23776435

Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

DTIC Science & Technology

2015-09-30

SST), sea surface height anomaly (SSH), chlorophyll a concentration (Chla), and primary productivity (PP). These data are available on similar...between the high and low area, and in areas with low abundance, chlorophyll a concentration was also a significant explanatory variable. For fin

Marine mammal distribution in the open ocean: a comparison of ocean color data products and levant time scales

NASA Astrophysics Data System (ADS)

Ohern, J.

2016-02-01

Marine mammals are generally located in areas of enhanced surface primary productivity, though they may forage much deeper within the water column and higher on the food chain. Numerous studies over the past several decades have utilized ocean color data from remote sensing instruments (CZCS, MODIS, and others) to asses both the quantity and time scales over which surface primary productivity relates to marine mammal distribution. In areas of sustained upwelling, primary productivity may essentially grow in the secondary levels of productivity (the zooplankton and nektonic species on which marine mammals forage). However, in many open ocean habitats a simple trophic cascade does not explain relatively short time lags between enhanced surface productivity and marine mammal presence. Other dynamic features that entrain prey or attract marine mammals may be responsible for the correlations between marine mammals and ocean color. In order to investigate these features, two MODIS (moderate imaging spectroradiometer) data products, the concentration as well as the standard deviation of surface chlorophyll were used in conjunction with marine mammal sightings collected within Ecuadorian waters. Time lags between enhanced surface chlorophyll and marine mammal presence were on the order of 2-4 weeks, however correlations were much stronger when the standard deviation of spatially binned images was used, rather than the chlorophyll concentrations. Time lags also varied between Balaenopterid and Odontocete cetaceans. Overall, the standard deviation of surface chlorophyll proved a useful tool for assessing potential relationships between marine mammal sightings and surface chlorophyll.

Ocean Chlorophyll as a Precursor of ENSO: An Earth System Modeling Study

NASA Astrophysics Data System (ADS)

Park, Jong-Yeon; Dunne, John P.; Stock, Charles A.

2018-02-01

Ocean chlorophyll concentration, a proxy for phytoplankton, is strongly influenced by internal ocean dynamics such as those associated with El Niño-Southern Oscillation (ENSO). Observations show that ocean chlorophyll responses to ENSO generally lead sea surface temperature (SST) responses in the equatorial Pacific. A long-term global Earth system model simulation incorporating marine biogeochemical processes also exhibits a preceding chlorophyll response. In contrast to simulated SST anomalies, which significantly lag the wind-driven subsurface heat response to ENSO, chlorophyll anomalies respond rapidly. Iron was found to be the key factor connecting the simulated surface chlorophyll anomalies to the subsurface ocean response. Westerly wind bursts decrease central Pacific chlorophyll by reducing iron supply through wind-driven thermocline deepening but increase western Pacific chlorophyll by enhancing the influx of coastal iron from the maritime continent. Our results mechanistically support the potential for chlorophyll-based indices to inform seasonal ENSO forecasts beyond previously identified SST-based indices.

Information content of in situ and remotely sensed chlorophyll-a: Learning from size-structured phytoplankton model

NASA Astrophysics Data System (ADS)

Laiolo, Leonardo; Matear, Richard; Baird, Mark E.; Soja-Woźniak, Monika; Doblin, Martina A.

2018-07-01

Chlorophyll-a measurements in the form of in situ observations and satellite ocean colour products are commonly used in data assimilation to calibrate marine biogeochemical models. Here, a two size-class phytoplankton biogeochemical model, with a 0D configuration, was used to simulate the surface chlorophyll-a dynamics (simulated surface Chl-a) for cyclonic and anticyclonic eddies off East Australia. An optical model was then used to calculate the inherent optical properties from the simulation and convert them into remote-sensing reflectance (Rrs). Subsequently, Rrs was used to produce a satellite-like estimate of the simulated surface Chl-a concentrations through the MODIS OC3M algorithm (simulated OC3M Chl-a). Identical parameter optimisation experiments were performed through the assimilation of the two separate datasets (simulated surface Chl-a and simulated OC3M Chl-a), with the purpose of investigating the contrasting information content of simulated surface Chl-a and remotely-sensed data sources. The results we present are based on the analysis of the distribution of a cost function, varying four parameters of the biogeochemical model. In our idealized experiments the simulated OC3M Chl-a product is a poor proxy for the total simulated surface Chl-a concentration. Furthermore, our result show the OC3M algorithm can underestimate the simulated chlorophyll-a concentration in offshore eddies off East Australia (Case I waters), because of the weak relationship between large-sized phytoplankton and remote-sensing reflectance. Although Case I waters are usually characteristic of oligotrophic environments, with a photosynthetic community typically represented by relatively small-sized phytoplankton, mesoscale features such as eddies can generate seasonally favourable conditions for a photosynthetic community with a greater proportion of large phytoplankton cells. Furthermore, our results show that in mesoscale features such as eddies, in situ chlorophyll-a observations and the ocean colour products can carry different information related to phytoplankton sizes. Assimilating both remote-sensing reflectance and measurements of in situ chlorophyll-a concentration reduces the uncertainty of the parameter values more than either data set alone, thus reducing the spread of acceptable solutions, giving an improved simulation of the natural environment.

Complex formation between chlorophyll a and cytochrome c: surface properties at the air-water interface. Absorbance, fluorescence and fluorescence-lifetime in Langmuir-Blodgett films.

PubMed

Lamarche, F; Picard, G; Téchy, F; Aghion, J; Leblanc, R M

1991-04-23

The binding of cytochrome c to an insoluble monolayer of chlorophyll a was studied. Surface pressure (II), surface potential (delta V) and [14C]cytochrome c surface-concentration (gamma) isotherms were measured versus molecular area (sigma) in mixed films. Compared to the successive-addition method, this procedure allows the formation of homogeneous mixed films. The cytochrome c is incorporated into a chlorophyll a monolayer, compressed at a surface pressure of 20 mN.m-1. On expansion, the quantity of protein incorporated into the monolayer gradually increases. Subsequent compression-expansion cycles result in similar isotherms, distinct from that measured during the first expansion. All surface properties measured, but more specifically the surface radioactivity of [14C]cytochrome c, indicate the irreversibility of protein incorporation into the chlorophyll a monolayer. In fact, surface properties of the binary film are completely different from the properties of either of the pure components. As a result, calculated values of surface potentials for mixed films using the additivity law deviate from experimentally measured potentials. The absorption and fluorescence spectra of mixed films transferred onto a solid substrate by the Langmuir-Blodgett technique, indicate a dilution effect of chlorophyll a by cytochrome c. However, the dilution effect cannot be detected by the fluorescence lifetimes of pure chlorophyll a and mixed chlorophyll a-cytochrome c films, both shorter than 0.2 ns. This provides support for the existence of an energy-transfer mechanism between chlorophyll a monomer and chlorophyll a aggregates which could serve as an energy trap. The role of the protein could be related to that of the matrix.

[Temporal and Spatial Characteristics of Lake Taihu Surface Albedo and Its Impact Factors].

PubMed

Cao, Chang; Li, Xu-hui; Zhang, Mi; Liu, Shou-dong; Xiao, Wei; Xiao, Qi-tao; Xu, Jia-ping

2015-10-01

Lake surface albedo determines energy balance of water-atmospheric interface and water physical environment. Solar elevation angle, cloudiness, wind speed, water quality and other factors can affect lake surface albedo. Using solar radiation, wind speed, and water quality data (turbidity and chlorophyll-a concentration) which were observed in four eddy covariance sites (Meiliangwan, Dapukou, Bifenggang and Xiaoleishan i. e. MLW, DPK, BFG and XLS) in Lake Taihu and clearness index (k(t)), the influence of these factors on Lake Taihu surface albedo and the reasons that led to its spatial difference were investigated. The results showed that solar elevation angle played a leading role in the diurnal and seasonal change of lake surface albedo; lake surface albedo reached two peaks in 0 < k(t) < 0.1 and 0.4 < k(t) < 0.6 respectively, when solar elevation angle was below 35 degrees. The surface albedo increased with the increasing wind speed, turbidity and chlorophyll-a concentration. However, wind could indirectly affect surface albedo through leading to the changes in sediment resuspension and chlorophyll-a distribution. The sequence of albedo in the four sites was XLS > BFG > DPK > MLW. XLS and BFG belonged to the higher albedo group, while DPK and MLW belonged to the lower albedo group. The different biological environments caused by aquatic macrophytes and algae resulting in the spatial variation of Lake Taihu surface albedo. The relationship between albedo and chlorophyll-a concentration was not a very sensitive factor for indicating the outbreak of algae. This study can provide theoretical reference for lake albedo parameterization.

An Optical Index of Phytoplankton Photoacclimation and Its Relation to Light-Saturated Photosynthesis in the Sea

NASA Technical Reports Server (NTRS)

Behrenfeld, Michael J.; Boss, Emmanuel; Lyon, Paul E.; Fennel, Katja; Hoge, Frank E.; Koblinsky, Chester J. (Technical Monitor)

2002-01-01

In relation to understanding ocean biology at the global scale, one of NASA's primary foci has been measurements of near-surface concentrations of phytoplankton chlorophyll. Chlorophyll is an important light-absorbing pigment in phytoplankton. The absorbed light energy is used to fix carbon in the process of photosynthesis. Photosynthesis, in turn, is critical to the growth of phytoplankton and the function of entire marine ecosystems. Thus, the use of satellite surface chlorophyll data to estimate primary production in the ocean has been a key focus of much biological oceanography research. One of the major challenges in this research is to develop relationships that allow a given chlorophyll concentration (a standing stock) to be interpreted in terms of carbon fixation (a rate). This problem centers on the description of the light-saturated photosynthetic rate, Pbmax. In this paper, we describe how optical measurements of light attenuation provide information on particulate organic carbon (POC) concentrations. We then show how the ratio of POC to chlorophyll (Theta) provides critical information on variability in Pbmax. We then test this relationship between Theta and Pbmax using field data from a variety of open ocean ecosystems.

Water color component analysis in saltwater intrusion reach: a case study in Shawan-Humen Watercourse, Pearl River Estuary

NASA Astrophysics Data System (ADS)

Fang, Li-gang; Chen, Shui-Sen; Li, Dan; Zhang, Lixin; Li, Dong

2008-11-01

The saline water color component characteristic (chlorophyll-a and chromophoric dissolved organic matter (CDOM)) and their spatial change tendency in the Pearl River Estuary from the In-situ data in December of 2006 was studied. Based on the experimental results, the mixing behavior of CDOM in the Shawan-Humen Watercourse was analyzed. The mixing behavior was controlled by topography, hydrological and biological factors, and the relationships among absorption characteristics of CDOM (at 400 nm, ag400). Contained is a discussion of chlorophyll-a concentration and salinity. The chlorophyll-a concentration decreases with increasing CDOM absorption under a salinity of 10, while the chlorophyll-a concentration decreases with increasing salinity. The salinity becomes less aggressive towards the Lingding Bay in the saltwater intrusion reach of Shawan-Humen, and a low chlorophyll-a concentration area occurs in the Shiziyang riverway where the salinity is greater than 20. The highest chlorophyll-a concentration of surface water was observed in the Dadaoshawei site of the Shawan tributary reach- where the saltwater and freshwater interface. The slope distribution of the CDOM spectral absorption curve in the Shawan-Humen watercourse was increased towards the Lingding Bay direction. The spectral slope S value of CDOM varied from 0.0107 to 0.0121 nm-1 with an average value of 0.0116 nm-1. This was an indication that the terrestrial river input was the main resource of CDOM in the Shawan-Humen watercourse. The high correlation (R2=0.9458)of surface water and bottom water (-7.5m ) salinity showed that salinity can be monitored by remote sensing. The ag400 in the saltwater intrusion reach showed conservative behavior, indicating strong characteristics of the CDOM it reflected. There was a correlative relationship between ag400, chlorophyll-a concentration and the salinity, showing that a water color analysis technique can be used to study the distribution and behavior of salinity, as well as saltwater intrusion to a certain extent.

An evaluation of the latitudinal gradient of chlorophyll in the California Current

NASA Astrophysics Data System (ADS)

Dietrich, W.; Broughton, J.; Kudela, R. M.

2013-12-01

Tracking of spatial and temporal trends in phytoplankton abundance and distribution is an important step toward understanding large-scale macroecological processes in the ocean. Measurements of ocean radiance from satellite-borne sensors, such as SeaWiFS and MODIS, can be used to estimate surface chlorophyll concentration, which is a good indicator of phytoplankton biomass. The primary goal of this study was to evaluate the latitudinal gradient in chlorophyll concentration within the California Current first reported by Ware and Thomson (2005). They found that average chlorophyll concentration tended to increase steadily from 32-48°N latitude. This concentration gradient was reevaluated using a longer dataset and an algorithm refined for the region. Radiance data from the MODIS-Aqua instrument were obtained for every year from 2002 through 2013. Data included annual averages of remote sensing radiance as well as monthly averages for February, April, and August. These months were chosen to represent each of the three oceanographic seasons present in the California Current. Estimates of chlorophyll concentration were derived from these data using the CALFIT algorithm developed by Kahru et al. (2012). The resulting maps of chlorophyll concentration were processed in MATLAB and linear regressions were performed using SYSTAT 13 software. A statistically significant (p < 0.05) latitudinal trend in chlorophyll was observed in the annual averaged data as well as in the averaged seasonal data from February and August. No significant trend was observed in the averaged April data. Chlorophyll concentration was positively correlated with latitude in every instance, except in April 2003 and April 2005, where a negative correlation was observed. The positive latitudinal trend was strongest during August and weakest during April. Strong peaks in chlorophyll were observed near San Francisco Bay and the mouth of the Columbia River, suggesting that river-borne nutrient input may be the dominant factor responsible for the existence of this chlorophyll gradient.

Quantifying the biological impact of surface ocean light attenuation by colored detrital matter in an ESM using a new optical parameterization

NASA Astrophysics Data System (ADS)

Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

2015-08-01

Light attenuation by colored detrital material (CDM) was included in a fully coupled Earth system model (ESM). This study presents a modified parameterization for shortwave attenuation, which is an empirical relationship between 244 concurrent measurements of the diffuse attenuation coefficient for downwelling irradiance, chlorophyll concentration and light absorption by CDM. Two ESM model runs using this parameterization were conducted, with and without light absorption by CDM. The light absorption coefficient for CDM was prescribed as the average of annual composite MODIS Aqua satellite data from 2002 to 2013. Comparing results from the two model runs shows that changes in light limitation associated with the inclusion of CDM decoupled trends between surface biomass and nutrients. Increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients. Instead, surface chlorophyll, biomass and nutrients increased together. These changes can be attributed to the different impact of light limitation on surface productivity versus total productivity. Chlorophyll and biomass increased near the surface but decreased at greater depths when CDM was included. The net effect over the euphotic zone was less total biomass leading to higher nutrient concentrations. Similar results were found in a regional analysis of the oceans by biome, investigating the spatial variability of response to changes in light limitation using a single parameterization for the surface ocean. In coastal regions, surface chlorophyll increased by 35 % while total integrated phytoplankton biomass diminished by 18 %. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while the largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by comparing the competing factors of diminished light availability and increased nutrient availability on phytoplankton growth in the upper 200 m. Understanding changes in biological productivity requires both surface and depth-resolved information. Surface trends may be minimal or of the opposite sign than depth-integrated amounts, depending on the vertical structure of phytoplankton abundance.

Ocean Processes Revealing by Seasonal Dynamics of Surface Chlorophyll Concentration (by Satellite Data)

NASA Astrophysics Data System (ADS)

Shevyrnogov, Anatoly; Vysotskaya, Galina

Continuous monitoring of phytopigment concentrations in the ocean by space-borne methods makes possible to estimate ecological condition of biocenoses in critical areas. Unlike land vege-tation, hydrological processes largely determine phytoplankton dynamics, which may be either recurrent or random. The types of chlorophyll concentration dynamics can manifest as zones quasistationary by seasonal chlorophyll dynamics, perennial variations of phytopigment con-centrations, anomalous variations, etc., that makes possible revealing of hydrological structure of the ocean. While large-scale and frequently occurring phenomena have been much studied, the seldom-occurring changes of small size may be of interest for analysis of long-term processes and rare natural variations. Along with this, the ability to reflect consequences of anthropoge-nous impact or natural ecological disasters on the ocean biota makes the anomalous variations ecologically essential. Civilization aspiring for steady development and preservation of the bio-sphere, must have the knowledge of spatial distribution, seasonal dynamics and anomalies of the primary production process on the planet. In the papers of the authors (Shevyrnogov A.P., Vysotskaya G.S., Gitelzon J.I. Quasistationary areas of chlorophyll concentration in the world ocean as observed satellite data. Adv. Space Res. Vol. 18, No. 7, pp. 129-132, 1996) existence of zones, which are quasi-stationary with similar seasonal dynamics of chlorophyll concentration at surface layer of ocean, was shown. Results were obtained on the base of pro-cessing of time series of satellite images SeaWiFS. It was shown that fronts and frontal zones coincide with dividing lines between quasi-stationary areas, especially in areas of large oceanic streams. Biota of surface oceanic layer is more stable in comparison with quickly changing sur-face temperature. It gives a possibility to circumvent influence of high-frequency component (for example, a diurnal cycle) in investigation of dynamics of spatial distribution of surface streams. In addition, an analyses of nonstable ocean productivity phenomena, stood out time series of satellite images, showed existence of areas with different types of instability in the all Global ocean. They are observed as adjacent nonstationary zones of different size, which are associated by different ways with known oceanic phenomena. It is evident that dynamics of a spatial distribution of biological productivity can give an additional knowledge of complicated picture of surface oceanic layer hydrology.

The impact of ENSO on regional chlorophyll-a anomaly in the Arafura Sea

NASA Astrophysics Data System (ADS)

Dewi, D. M. P. R.; Fatmasari, D.; Kurniawan, A.; Munandar, M. A.

2018-03-01

The El Niño-Southern Oscillation (ENSO) is a naturally occurring phenomenon that involves fluctuating ocean temperature in the equatorial Pacific. ENSO influences ocean climate variability in Indonesia including the Arafura Sea. The relationship between oceanic chlorophyll-a and ENSO has been the focus of study over the past decade. Here we examine the impact of ENSO on regional chlorophyll-a anomaly in the Papua waters using 14 years of chlorophyll-a and sea surface temperature (SST) data from AQUA MODIS and sea level anomaly data from AVISO. It is found that when El Niño events occur the negative SST anomaly in the Papua waters as well as the enhanced upwelling cause the increase of chlorophyll-a concentration. The highest chlorophyll-a concentration (> 1 mg–cm-3) occured during El Niño and observed around the Aru archipelago. In contrast during La Niña event, the positive SST anomaly in Papua waters and the suppressed upwelling cause the decrease of chlorophyll-a concentration. Our results suggest that during El Niño (La Niña), the enhanced (suppressed) upwelling related to the significant decreasing (increasing) of sea level anomaly.

Estimation of chlorophyll-a concentration on an inland lake by using satellite data.

NASA Astrophysics Data System (ADS)

Iwata, T.

2017-12-01

Chlorophyll concentration is common as an index of water quality and phytoplankton activity in coastal areas and lake water. In this research, we propose a method to estimate chlorophyll-a distribution of lake surface by using satellite data. The satellite data used is the sea surface reflectance of 3 channels of band-9, -10, and -12 by MODIS/Aqua MYDOCGA data provided by NASA/EOSDIS, and its data resolution is spatially 1 km and temporally 1 day. As index for estimating chlorophyll-a from reflection intensity, four indices of two types are proposed and comparatively analyzed. One of the two types is the ratio of the reflectance of the visible green light band (Gr) to the one of the visible blue light band (Bl), and the other index is obtained by normalizing difference of the reflectance between two bands. The two types of indices are expressed as follows. * Band ratio (BR) = Gr / Bl * Normalized difference (ND) = (Gr-Bl) / (Gr+Bl) As the visible blue light band, band-9 (438-448 nm) and band-10 (483-493 nm) were used. The four indices are represented as BR9, BR10, ND9, and ND10. The Lake Biwa in Japan is selected as the test area to be analyzed. At the Lake, temperature and the chlorophyll-a concentration around the lake center are periodically measured every month, and data is published. From April 2011 to December 2015, correlation analysis was done using 29 data on which the water measurement date and the valid satellite data acquisition date coincided ( Fig.1 and 2 ). Based on the analysis, the following two formulas were shown as models that can successfully express surface chlorophyll-a concentration. * Chl-a [μg/L] = 6.11×BR10 - 2.61 * Chl-a [μg/L] = 32.6×ND102 + 10.2×ND10 + 3.24

Ocean Chlorophyll Studies from a U-2 Aircraft Platform

NASA Technical Reports Server (NTRS)

Kim, H. H.; Mcclain, C. R.; Blaine, L. R.; Hart, W. D.; Atkinson, L. P.; Yoder, J. A.

1979-01-01

Chlorophyll gradient maps of large ocean areas were generated from U-2 ocean color scanner data obtained over test sites in the Pacific and Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and ocean surface can be properly modeled using a measurement made at 778 nm. An estimation of the chlorophyll concentration was performed by properly ratioing radiances measured at 472 nm and 548 nm after removing the atmospheric effects. The correlation between the remotely sensed data and in-situ surface chlorophyll measurements was validated in two sets of data. The results show that the correlation between the in-situ measured chlorophyll and the derived quantity is a negative exponential function and the correlation coefficient was calculated to be -0.965.

Effects of oceanographic factors on spatial distribution of Whale Shark in Cendrawasih Bay National Park, West Papua

NASA Astrophysics Data System (ADS)

Ranintyari, Maulida; Sunarto; Syamsuddin, Mega L.; Astuty, Sri

2018-05-01

Whale sharks are a leading species in Cendrawasih Bay due to its benign nature and its regular appearance. Recently, whale sharks are vulnerable to scarcity and even extinction. One of the efforts to maintain the existence of the whale shark population is by knowing its spatial distribution. This study aims to analyze how the oceanographic factors affect the spatial distribution of whale sharks in Cendrawasih Bay National Park. The method used in this research is descriptive with the quantitative approach using the Generalized Additive Model (GAM) analysis. The data consisted of the whale shark monitoring data in TNTC taken by WWF-Indonesia, and image data of sea surface temperature (SST) and chlorophyll-a concentration of Aqua-MODIS, and also sea surface current from Aviso. Analyses were conducted for the period of January 2012 until March 2015. The GAM result indicated that sea surface current was better than the other environment (SST and chlorophyll-a concentration) as an oceanographic predictor of whale shark appearance. High probabilities of the whale shark’s to appear on the surface were observed in sea surface current velocities between 0.30-0.60 m/s, for SST ranged from 30.50-31.80 °C, and for chlorophyll-a concentration ranged from 0.20-0.40 mg/m3.

Biological response to coastal upwelling and dust deposition in the area off Northwest Africa

NASA Astrophysics Data System (ADS)

Ohde, T.; Siegel, H.

2010-05-01

Nutrient supply in the area off Northwest Africa is mainly regulated by two processes, coastal upwelling and deposition of Saharan dust. In the present study, both processes were analyzed and evaluated by different methods, including cross-correlation, multiple correlation, and event statistics, using remotely sensed proxies of the period from 2000 to 2008 to investigate their influence on the marine environment. The remotely sensed chlorophyll- a concentration was used as a proxy for the phytoplankton biomass stimulated by nutrient supply into the euphotic zone from deeper water layers and from the atmosphere. Satellite-derived alongshore wind stress and sea-surface temperature were applied as proxies for the strength and reflection of coastal upwelling processes. The westward wind and the dust component of the aerosol optical depth describe the transport direction of atmospheric dust and the atmospheric dust column load. Alongshore wind stress and induced upwelling processes were most significantly responsible for the surface chlorophyll- a variability, accounting for about 24% of the total variance, mainly in the winter and spring due to the strong north-easterly trade winds. The remotely sensed proxies allowed determination of time lags between biological response and its forcing processes. A delay of up to 16 days in the surface chlorophyll- a concentration due to the alongshore wind stress was determined in the northern winter and spring. Although input of atmospheric iron by dust storms can stimulate new phytoplankton production in the study area, only 5% of the surface chlorophyll- a variability could be ascribed to the dust component in the aerosol optical depth. All strong desert storms were identified by an event statistics in the time period from 2000 to 2008. The 57 strong storms were studied in relation to their biological response. Six events were clearly detected in which an increase of chlorophyll- a was caused by Saharan dust input and not by coastal upwelling processes. Time lags of <8 days, 8 days, and 16 days were determined. An increase in surface chlorophyll- a concentration of up to 2.4 mg m -3 after dust storms in which the dust component of the aerosol optical depth was up to 0.9 was observed.

Remote sensing of ocean currents using ERTS imagery

NASA Technical Reports Server (NTRS)

Maul, G. A.

1973-01-01

Major ocean currents such as the Loop Current in the eastern Gulf of Mexico have surface manifestations which can be exploited for remote sensing. Surface chlorophyll-a concentrations, which contribute to the shift in color from blue to green in the open sea, were found to have high spatial variability; significantly lower concentrations were observed in the current. The cyclonic edge of the current is an accumulation zone which causes a peak in chlorophyll concentration. The dynamics also cause surface concentrations of algae, which have a high reflectance in the near infrared. Combining these observations gives rise to an edge effect which can show up as a bright lineation on multispectral imagery delimiting the current's boundary under certain environmental conditions. When high seas introduce bubbles, white caps, and foam, the reflectance is dominated by scattering rather than absorption. This has been detected in ERTS imagery and used for current location.

Enhancement of Chlorophyll Concentration and Growing Harmful Algal Bloom Along the California Coast

NASA Astrophysics Data System (ADS)

Aceves, Joselyn; Singh, Ramesh

2016-07-01

We have carried out detailed analysis of satellite and ground data at different locations, Cal Poly, Goleta, Newport, Santa Monica, and Scripps piers and Monterey, Stearns and Santa Cruz wharfs along the California coast for the period 2008-2015. The sea surface temperature and chlorophyll concentrations derived from satellite data are analyzed together with ground observations of nitrogen, phosphorus, domoic acids and harmful algal blooms. The frequency of harmful algal blooms are found to increase in recent years depending upon the enhancement of chlorophyll concentrations and the discharges along the coast and dynamics of the sea surface temperature. The frequency of harmful algal blooms is higher in the northern California compared to southern California. The anthropogenic activities along the coast have increased which are associated with the forest fires and long range transport of dusts from Asia. The aerosol optical depth derived from satellite data during summer months seems to play an important role in the frequency of harmful algal blooms.

Mining a sea of data: deducing the environmental controls of ocean chlorophyll.

PubMed

Irwin, Andrew J; Finkel, Zoe V

2008-01-01

Chlorophyll biomass in the surface ocean is regulated by a complex interaction of physiological, oceanographic, and ecological factors and in turn regulates the rates of primary production and export of organic carbon to the deep ocean. Mechanistic models of phytoplankton responses to climate change require the parameterization of many processes of which we have limited knowledge. We develop a statistical approach to estimate the response of remote-sensed ocean chlorophyll to a variety of physical and chemical variables. Irradiance over the mixed layer depth, surface nitrate, sea-surface temperature, and latitude and longitude together can predict 83% of the variation in log chlorophyll in the North Atlantic. Light and nitrate regulate biomass through an empirically determined minimum function explaining nearly 50% of the variation in log chlorophyll by themselves and confirming that either light or macronutrients are often limiting and that much of the variation in chlorophyll concentration is determined by bottom-up mechanisms. Assuming the dynamics of the future ocean are governed by the same processes at work today, we should be able to apply these response functions to future climate change scenarios, with changes in temperature, nutrient distributions, irradiance, and ocean physics.

Seasonal dynamics of surface chlorophyll concentration and sea surface temperature, as indicator of hydrological structure of the ocean (by satellite data)

NASA Astrophysics Data System (ADS)

Shevyrnogov, Anatoly; Vysotskaya, Galina

Continuous monitoring of phytopigment concentrations and sea surface temperature in the ocean by space-borne methods makes possible to estimate ecological condition of biocenoses in critical areas. Unlike land vegetation, hydrological processes largely determine phytoplank-ton dynamics, which may be either recurrent or random. The types of chlorophyll concentration dynamics and sea surface temperature can manifest as zones quasistationary by seasonal dynamics, quasistationary areas (QSA). In the papers of the authors (A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov, A study of the stationary and the anomalous in the ocean surface chlorophyll distribution by satellite data. International Journal of Remote Sensing, Vol. 25, No.7-8, pp. 1383-1387, April 2004 & A. P. Shevyrnogov, G. S. Vysotskaya, J. I. Gitelson, Quasistationary areas of chlorophyll concentra-tion in the world ocean as observed satellite data Advances in Space Research, Volume 18, Issue 7, Pages 129-132, 1996) existence of zones, which are quasi-stationary with similar seasonal dynamics of chlorophyll concentration at surface layer of ocean, was shown. Results were obtained on the base of processing of time series of satellite images SeaWiFS. It was shown that fronts and frontal zones coincide with dividing lines between quasi-stationary are-as, especially in areas of large oceanic streams. To study the dynamics of the ocean for the period from 1985 through 2012 we used data on the temperature of the surface layer of the ocean and chlorophyll concentration (AVHRR, SeaWiFS and MODIS). Biota of surface oceanic layer is more stable in comparison with quickly changing surface tem-perature. It gives a possibility to circumvent influence of high-frequency component (for exam-ple, a diurnal cycle) in investigation of dynamics of spatial distribution of surface streams. In addition, an analyses of nonstable ocean productivity phenomena, stood out time series of satellite images, showed existence of areas with different types of instability in the all Global ocean. They are observed as adjacent nonstationary zones of different size, which are associ-ated by different ways with known oceanic phenomena. It is evident that dynamics of a spatial distribution of biological productivity can give an additional knowledge of complicated picture of surface oceanic layer hydrology. In this study we demonstrate different origin of appearance of quasistationary zones in the ocean. We can see that the border between quasi¬stationary zones is an indicator of the front between the Labrador Current and Gulfstream, other example of revealed pheno¬menon is a qua-sistationary area around of the British Isles that correlates with the relief of the oceanic bottom. Considering that the QSA maps are calculated almost for all surface of the Global ocean, not all QSA can be explained especially of small size. Although some small QSA are interesting. Also local QSA near estuaries of large rivers and large industrial centers, that can be result of a human impact. In sum satellite data is a powerful instrument for investigation of dynamic oceanic processes, their stability and unstability. The result of such study can be used for monitoring of long-term changes and their correlation of with climate dynamics.

Annual phytoplankton blooming using satellite-derived chlorophyll-a data around the Vitória-Trindade Chain, Southeastern Brazil

NASA Astrophysics Data System (ADS)

Lemos, A. T.; Ghisolfi, R. D. R.; Mazzini, P. L. F.

2018-06-01

The present study aimed to investigate the influence that four seamounts of the Vitória-Trindade Chain (VTC): the Vitória (VB), Jaseur (JB), Davis (DB) and Dogaressa (DoB) Banks, located on the western South Atlantic Ocean, potentially exert on the annual variability of the chlorophyll-a concentration [Chla] over their summits and surrounding regions. Nine years (January 2003 to December 2011) of monthly and weekly (8-days composite) satellite derived chlorophyll-a concentration, with 4 km spatial resolution were obtained for the study area using the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Aqua satellite. For comparison purposes, different time-series were analyzed for both the region over the seamounts and the surrounding waters. A Gaussian model was adjusted to each of the time series of monthly mean chlorophyll-a concentration, and the curve parameters were used in order to objectively characterize the blooms. The results showed that the entire study area (both above and beyond the seamounts) underwent seasonal blooms, with peak of chlorophyll-a occurring around the austral winter (June, July and August), when due to surface cooling the deepening of the surface mixed layer is observed, enriching the photic zone with nutrients. Nevertheless, the peak chlorophyll-a concentration over the shallow seamounts was twice higher than that over deep seamounts or in the adjacent deep ocean. Our results suggest that the presence of these seamounts and their morphological characteristics can significantly impact the primary productivity observed in this region. Thus, the VTC can be divided into areas of diffuse [Chla] (VB and JB), with lower zonal scattering and higher phytoplankton concentrations (DB), and areas distant from the continental shelf and the mesoscale processes that develop there, hence with lower [Chla] (DoB). The profound impact that these seamounts have on the oceanic ecosystem may turn them into becoming true oasis in the oligotrophic deep ocean, supporting higher trophic levels, as well as important fisheries in this region.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foltz, Gregory R.; Balaguru, Karthik; Leung, Lai-Yung R.

The impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998–2011. Previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone-induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of cyclone-induced changes in mixed layer depth, here it is shown that accumulated cyclone energy explains 22% of the interannual variability in seasonally-averaged (June–November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explainedmore » by tropical cyclones is thus about 70% of that explained by the NAO, which has well-known impacts in this region. It is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.« less

Global Marine Productivity and Living-Phytoplankton Carbon Biomass Estimated from a Physiological Growth Model

NASA Astrophysics Data System (ADS)

Arteaga, L.; Pahlow, M.; Oschlies, A.

2016-02-01

Primay production by marine phytoplankton essentially drives the oceanic biological carbon pump. Global productivity estimates are commonly founded on chlorophyll-based primary production models. However, a major drawback of most of these models is that variations in chlorophyll concentration do not necessarily account for changes in phytoplankton biomass resulting from the physiological regulation of the chlorophyll-to-carbon ratio (Chl:C). Here we present phytoplankton production rates and surface phytoplankton C concentrations for the global ocean for 2005-2010, obtained by combining satellite Chl observations with a mechanistic model for the acclimation of phytoplankton stoichiometry to variations in nutrients, light and temperature. We compare our inferred phytoplankton C concentrations with an independent estimate of surface particulate organic carbon (POC) to identify for the first time the global contribution of living phytoplankton to total POC in the surface ocean. Our annual primary production (46 Pg C yr-1) is in good agreement with other C-based model estimates obtained from satellite observations. We find that most of the oligotrophic surface ocean is dominated by living phytoplankton biomass (between 30-70% of total particulate carbon). Lower contributions are found in the tropical Pacific (10-30% phytoplankton) and the Southern Ocean (≈ 10%). Our method provides a novel analytical tool for identifying changes in marine plankton communities and carbon cycling.

Vertical Distributions of Coccolithophores, PIC, POC, Biogenic Silica, and Chlorophyll a Throughout the Global Ocean.

PubMed

Balch, William M; Bowler, Bruce C; Drapeau, David T; Lubelczyk, Laura C; Lyczkowski, Emily

2018-01-01

Coccolithophores are a critical component of global biogeochemistry, export fluxes, and seawater optical properties. We derive globally significant relationships to estimate integrated coccolithophore and coccolith concentrations as well as integrated concentrations of particulate inorganic carbon (PIC) from their respective surface concentration. We also examine surface versus integral relationships for other biogeochemical variables contributed by all phytoplankton (e.g., chlorophyll a and particulate organic carbon) or diatoms (biogenic silica). Integrals are calculated using both 100 m integrals and euphotic zone integrals (depth of 1% surface photosynthetically available radiation). Surface concentrations are parameterized in either volumetric units (e.g., m -3 ) or values integrated over the top optical depth. Various relationships between surface concentrations and integrated values demonstrate that when surface concentrations are above a specific threshold, the vertical distribution of the property is biased to the surface layer, and when surface concentrations are below a specific threshold, the vertical distributions of the properties are biased to subsurface maxima. Results also show a highly predictable decrease in explained-variance as vertical distributions become more vertically heterogeneous. These relationships have fundamental utility for extrapolating surface ocean color remote sensing measurements to 100 m depth or to the base of the euphotic zone, well beyond the depths of detection for passive ocean color remote sensors. Greatest integrated concentrations of PIC, coccoliths, and coccolithophores are found when there is moderate stratification at the base of the euphotic zone.

Vertical Distributions of Coccolithophores, PIC, POC, Biogenic Silica, and Chlorophyll a Throughout the Global Ocean

PubMed Central

Bowler, Bruce C.; Drapeau, David T.; Lubelczyk, Laura C.; Lyczkowski, Emily

2018-01-01

Abstract Coccolithophores are a critical component of global biogeochemistry, export fluxes, and seawater optical properties. We derive globally significant relationships to estimate integrated coccolithophore and coccolith concentrations as well as integrated concentrations of particulate inorganic carbon (PIC) from their respective surface concentration. We also examine surface versus integral relationships for other biogeochemical variables contributed by all phytoplankton (e.g., chlorophyll a and particulate organic carbon) or diatoms (biogenic silica). Integrals are calculated using both 100 m integrals and euphotic zone integrals (depth of 1% surface photosynthetically available radiation). Surface concentrations are parameterized in either volumetric units (e.g., m−3) or values integrated over the top optical depth. Various relationships between surface concentrations and integrated values demonstrate that when surface concentrations are above a specific threshold, the vertical distribution of the property is biased to the surface layer, and when surface concentrations are below a specific threshold, the vertical distributions of the properties are biased to subsurface maxima. Results also show a highly predictable decrease in explained‐variance as vertical distributions become more vertically heterogeneous. These relationships have fundamental utility for extrapolating surface ocean color remote sensing measurements to 100 m depth or to the base of the euphotic zone, well beyond the depths of detection for passive ocean color remote sensors. Greatest integrated concentrations of PIC, coccoliths, and coccolithophores are found when there is moderate stratification at the base of the euphotic zone. PMID:29576683

Cyanobacterial bloom in the world largest freshwater lake Baikal

NASA Astrophysics Data System (ADS)

Namsaraev, Zorigto; Melnikova, Anna; Ivanov, Vasiliy; Komova, Anastasia; Teslyuk, Anton

2018-02-01

Lake Baikal is a UNESCO World Heritage Site and holds 20% of the world’s freshwater reserves. On July 26, 2016, a cyanobacterial bloom of a green colour a few kilometers in size with a bad odor was discovered by local people in the Barguzinsky Bay on the eastern shore of Lake Baikal. Our study showed very high concentration of chlorophyll a (41.7 g/m3) in the sample of bloom. We found that the bloom was dominated by a nitrogen-fixing heterocystous cyanobacteria of the genus Dolichospermum. The mass accumulation of cyanobacteria in the lake water with an extremely high chlorophyll a concentration can be explained by a combination of several factors: the discharge of biologicaly-available nutrients, including phosphorus, into the water of Lake Baikal; low wind speed and weak water mixing; buoyant cyanobacterial cells on the lake surface, which drifted towards the eastern coast, where the maximum concentration of chlorophyll a was recorded. In the center of the Barguzinsky Bay and in the open part of Lake Baikal, according to satellite data, the chlorophyll a concentration is several orders of magnitude lower than at the shoreline.

Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

NASA Astrophysics Data System (ADS)

Sauzède, R.; Lavigne, H.; Claustre, H.; Uitz, J.; Schmechtig, C.; D'Ortenzio, F.; Guinet, C.; Pesant, S.

2015-04-01

In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted in phytoplankton biomass (i.e. chlorophyll a concentration) and size-based community composition (i.e. microphytoplankton, nanophytoplankton and picophytoplankton), using a~method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over five decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available in open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition: http://doi.pangaea.de/10.1594/PANGAEA.844485.

Linking phytoplankton nitrogen uptake, macronutrients and chlorophyll- a in SW Atlantic waters: The case of the Gulf of San Jorge, Argentina

NASA Astrophysics Data System (ADS)

Paparazzo, Flavio E.; Williams, Gabriela N.; Pisoni, Juan P.; Solís, Miriam; Esteves, José L.; Varela, Diana E.

2017-08-01

We compared biological and chemical parameters in surface waters of the Gulf of San Jorge to better understand carbon export and the factors that control phytoplankton production in an area of the Argentinian Continental Shelf, a vastly under sampled region of the SW Atlantic Ocean. In April of 2012, we estimated new and regenerated primary production in the Gulf by measuring nitrate and ammonium uptake, respectively. We also measured macronutrient, and in situ chlorophyll-a concentrations, which were compared to chlorophyll-a estimates from remote sensing. Although the Gulf of San Jorge presents high levels of chlorophyll-a and primary production, the relationship between these parameters is not straightforward. Previous studies showed that surface chlorophyll-a explains only part of the variance in euphotic-zone integrated primary production, and that satellite-derived chlorophyll-a underestimates in situ primary production. Our results showed large spatial variability in the Gulf, with transitional physico-chemical conditions, such as fronts, that could favor an increase in biological production. In situ chlorophyll-a concentrations were highest at the mid-shelf station (6.0 mg m- 3) and lowest at the northernmost location by an order of magnitude. Remote sensing measurements of chlorophyll-a underestimated our in situ chlorophyll-a concentrations. Total nitrogen (nitrate + ammonium) uptake showed relatively similar rates throughout the study area (≈ 130 nM-N d- 1), except in the northernmost station where it was much lower (53 nM-N d- 1). This north region had a distinct water mass and maximal levels of macronutrients (nitrate ≈ 6 μM, ammonium ≈ 1.2 μM, phosphate ≈ 1.2 μM and silicic acid ≈ 4 μM). For the entire sampling region, chlorophyll-a concentrations strongly correlated with total nitrogen uptake (r = 0.76, n = 8, p < 0.05) and new primary production (r = 0.78, n = 8, p < 0.05). Values of the f-ratio were 0.9 in mid-shelf, and ranged between 0.35 and 0.45 in inner and coastal stations. Our results indicate that highest carbon export may occur in the outer part of the Gulf, closer to the mid-shelf region. Further studies will be necessary to better understand the functioning of this ecosystem, including the impact of fisheries and horizontal transport by currents in the overall CO2 balance.

Estimating chlorophyll content and bathymetry of Lake Tahoe using AVIRIS data

NASA Technical Reports Server (NTRS)

Hamilton, Michael K.; Davis, Curtiss O.; Rhea, W. J.; Pilorz, Stuart H.; Carder, Kendall L.

1993-01-01

Data on chlorophyll content and bathymetry of Lake Tahoe obtained on August 9, 1990 by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) are compared to concurrent in situ surface and in-water measurements. Measured parameters included profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, spectral upwelling and downwelling irradiance, and upwelling radiance. Several analyses were performed illustrating the utility of the AVIRIS over a dark water scene. Image-derived chlorophyll concentration compared extremely well with that measured with bottle samples. A bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings.

Remote sensing of chlorophyll concentration: State-of-the-art, 1975

NASA Technical Reports Server (NTRS)

Atwell, B. H.

1976-01-01

Remote measurement of chlorophyll concentration of the world's oceans from satellite observations could potentially be extremely useful for assessments of productivity in large areas for which measurements by other means would be impractical. The basis of these measurements rests with the physics of the interaction of light with material dissolved and suspended in the water. It is theoretically possible to predict the nature of light upwelled from the ocean surface from a solution to the radiative transfer equation. Practically, however, this is difficult. Monte-Carlo methods presently are thought to be the most viable method to treat the general theoretical problem. With restrictive assumptions of the nature of scattering, it is possible to construct simpler models. Algorithms developed to relate chlorophyll concentration (or some other parameter, i.e., seechi depth) to the upwelled light spectrum are discussed.

The optical and physiological properties of phytoplankton - base of model for estimation of primary production in the sea from satellite data.

NASA Astrophysics Data System (ADS)

Finenko, Z. Z.; Churilova, T. Ya.

An assessment of the spatial and temporal variation in the photo physiological parameters and chlorophyll-specific absorption coefficients of marine phytoplankton is essential for estimate of global primary production by satellite data. Relationships of photosynthesis rate on light intensity have been used for estimation of two photosynthetic parameters of phytoplankton in the Black Sea: light saturated photosynthesis intensity (Pb/max, mgC mg Chl-1 h-1) and photosynthesis efficiency (alpha/b mgC mg Chl -1 h-1/ W m-2). The results have shown that variability of photosynthetic parameters of surface phytoplankton during the year varied by one order of values: Pb/max - from 1 to 11 mg C mg Chl-1 h-1 and (alpha/b - from 0.04 to 0.35 mg C mg Chl-1 h-1/Wm-2. Temporal dynamics was characterised by increasing of the values from winter to summer and decreasing to the end of the year. The vertical profiles of Pb/max and alpha/b had opposite character of change: values of Pb/max decreased with depth, alpha/b - increased. Photosynthetic parameters changed with depth more significantly at time of stratification, than - without stratification. The influence of temperature, nitrate concentration and light intensity on Pb/max rather evidence, but temperature and optical depth effect on Pb/max more significantly. Depth-dependent variability of photosynthesis efficiency is generally effected of nutrient concentration. Vertical uniformity of maximum quantum yield of photosynthesis (Fm) and spectral mean absorption coefficient of phytoplankton (aph) in euphotic zone were obtained for cold period of year. In summer - Fm increased from surface to bottom of euphotic zone, aph - decrease. Fm and aph values of surface phytoplankton depended on chlorophyll concentration but their changes had opposite direction: Fm - increased and aph - decreased when chlorophyll concentration grew. As a result Pb/max = Z Fm aph Ik T and alpha/b = Z Fm aph T (where Z - a dimensional constant equal to the atomic mass of carbon, Ik - the photon flux density at which photosynthesis rate becomes light saturated, (mol photons m-2 s-1; T - a constant value for transition from seconds by one hour) change in 2-3 times for the range of chlorophyll concentration (0.05-10.0 mg m-3 ). Pb/max and alpha/b have been approximated by one-peaked curve with maximum at 3 mg m -3 Chl a concentration. These relationships could be used for modeling of Pb/max and alpha/b based on surface chlorophyll concentrations from satellite colour images.

Pigment biomarkers and particulate carbon in the upper water column compared to the ocean interior of the northeast Atlantic

NASA Astrophysics Data System (ADS)

Llewellyn, C. A.; Mantoura, R. F. C.

1996-08-01

In situ pumps (SAPs) were used to collect particulates from the upper and interior of the ocean at 47, 56 and 60°N along the 20°W meridian in the northeast Atlantic during 1989. The particulates were analysed for carbon, chlorophylls, chlorophyll degradation products and carotenoids covering a four order of magnitude change in concentration. There was a logarithmic decline in pigment and carbon concentrations from the surface to 1000 m, below which concentrations remained constant. The gradient of the decline for chlorophyll a (chl a) appeared to be directly related to the flux of organic matter from the upper ocean. 19'-Hexanoyloxyfucoxanthin (prymnesiophtyes) and fucoxanthin (diatoms) persisted throughout the water column revealing the importance of prymnesiophytes as well as diatoms in the transfer of biogenic material into the ocean interior. At 60°N there was a two order of magnitude decrease in chl a concentrations in the ocean interior compared to the surface (1 μg chl a l -1). At 47°N, surface chl a concentrations were similar to those 60°N, but in the ocean interior there was a three order of magnitude decrease. Chlorophyll a concentrations throughout the water column and differences in the type of assessory pigment present at the four latitudes were consistent with the timing of the spring bloom at each latitude. At 60°N, we sampled at the end of the spring bloom, and fucoxanthin dominated. At 47°N, the spring bloom was over, and 19'-hexanoyloxyfucoxanthin dominated. Pheophorbide a and pyropheophorbide a were the dominant chlorophyll degradation products, with highest concentrations in the north. Pyropheophorbide a became increasingly important with depth and towards the south. At least 50% of the organic carbon in the upper ocean could not be accounted for in terms of phytoplankton, zooplankton or bacteria, and we speculate that some of the unidentified carbon is related to microzooplankton faecal material. Carbon vertical profiles did not show the large latitudinal variation of the pigments, resulting in carbon/chl a ratios in the ocean interior at 47°N (1855) being 6-fold greater than those at 60°N. The ratios reflected the more highly degraded nature of the biogenic material in the ocean interior at 47°N compared to 60°N.

Evaluation of Bio-optical Algorithms for Chlorophyll Mapping in the Southwestern Atlantic

NASA Astrophysics Data System (ADS)

Garcia, V. M.; Garcia, C. A.; Signorini, S.; McClain, C. R.

2005-05-01

Efforts have been made over the past decade to study bio-optical properties of seawater in the Southwestern Atlantic for mapping chlorophyll concentration from space. Coastal regions deserve a greater attention due to the optical complexity from continental influence. Here we present an attempt to derive reliable bio-optical chlorophyll algorithms in the shelf region 25-40o S and 60-45o W. This area is subject to large optical interference by continental runoffs from La Plata River and Patos Lagoon. Spectral upwelling radiance and surface chlorophyll concentration data have been collected in the past years and have been used to generate a regional version of the NASA's OC2v4 model. The regional 2-band algorithm (termed OC2-LP), reduces chlorophyll positive bias to 11% as compared to the global SeaWiFS OC4v4 algorithm (bias = 27%). However, OC2-LP remains with an overall inaccuracy of over 40% in chlorophyll concentration, as calculated by the absolute percentage difference between in-situ and model-derived values. In-situ chlorophyll data from two cruises to the study region (La Plata I - winter of 2003 and La Plata II - summer of 2004) have been used to test the accuracy of the derived algorithm as well as the global version. A marked seasonal difference was found, where both OC4v4 and OC2-LP overestimate chlorophyll in summer at a higher magnitude than in the winter. These results indicate the need for other approaches rather than use of empirical band-ratio models in coastal waters of this region.

Remote sensing tools to study ocean biogeochemistry: state of the art

NASA Technical Reports Server (NTRS)

Carr, M. E.

2001-01-01

Remote sensing of the world ocean presently provides measurements of sea-surface temperature, sea surface height, wind speed and direction, and ocean color, from which chlorophyll concentration and aerosol optical thickness are obtained.

Evaluating the relationship between leaf chlorophyll concentration and SPAD-502 chlorophyll meter readings.

PubMed

Uddling, J; Gelang-Alfredsson, J; Piikki, K; Pleijel, H

2007-01-01

Relationships between chlorophyll concentration ([chl]) and SPAD values were determined for birch, wheat, and potato. For all three species, the relationships were non-linear with an increasing slope with increasing SPAD. The relationships for birch and wheat were strong (r (2) approximately 0.9), while the potato relationship was comparatively weak (r (2) approximately 0.5). Birch and wheat had very similar relationships when the chlorophyll concentration was expressed per unit leaf area, but diverged when it was expressed per unit fresh weight. Furthermore, wheat showed similar SPAD-[chl] relationships for two different cultivars and during two different growing seasons. The curvilinear shape of the SPAD-[chl] relationships agreed well with the simulated effects of non-uniform chlorophyll distribution across the leaf surface and multiple scattering, causing deviations from linearity in the high and low SPAD range, respectively. The effect of non-uniformly distributed chlorophyll is likely to be more important in explaining the non-linearity in the empirical relationships, since the effect of scattering was predicted to be comparatively weak. The simulations were based on the algorithm for the calculation of SPAD-502 output values. We suggest that SPAD calibration curves should generally be parameterised as non-linear equations, and we hope that the relationships between [chl] and SPAD and the simulations of the present study can facilitate the interpretation of chlorophyll meter calibrations in relation to optical properties of leaves in future studies.

The Northeast Monsoon's Impact on Mixing, Phytoplankton Biomass and Nutrient Cycling in the Arabian Sea

NASA Technical Reports Server (NTRS)

Wiggert, J. D.; Jones, B. H.; Dickey, T. D.; Brink, K. H.; Weller, R. A.; Marra, J.; Codispoti, L. A.

2000-01-01

In the northern Arabian Sea, atmospheric conditions during the Northeast (winter) Monsoon lead to deep convective mixing. Due to the proximity of the permanent pyncnocline to the sea surface, this mixing does not penetrate below 125 m. However, a strong nitracline is also present and the deep convection results in significant nitrate flux into the surface waters. This leads to nitrate concentrations over the upper 100 m that exceed 4 micrometers toward the end of the Monsoon. During the 1994/1995 US JGOFS/Arabian Sea expedition, the mean areal gross primary production over two successive Northeast Monsoons was determined to be 1.35gC/sq m/d. Thus, despite the deep penetrative convection, high rates of primary productivity were maintained. An interdisciplinary model was developed to elucidate the biogeochemical processes involved in supporting the elevated productivity. This model consists of a 1-D mixed-layer model coupled to a set of equations that tracked phytoplankton growth and the concentration of the two major nutrients (nitrate and ammonium). Zooplankton grazing was parameterized by rate constant determined by shipboard experiments. Model boundary conditions consist of meteorological time-series measured from the surface buoy that was part of the ONR Arabian Sea Experiment's central mooring. Our numerical experiments show that elevated surface evaporation, and the associated salinization of the mixed layer, strongly contributes to the frequency and penetration depth of the observed convective mixing. Cooler surface temperatures, increased nitrate entrainment, reduced water column stratification, and lower near-surface chlorophyll a concentrations all result from this enhanced mixing. The model also captured a dependence on regenerated nitrogen observed in nutrient uptake experiments performed during the Northeast Monsoon. Our numerical experiments also indicate that variability in mean pycnocline depth causes up to a 25% reduction in areal chlorophyll a concentration. We hypothesize that such shifts in pycnocline depth may contribute to the interannual variations in primary production and surface chlorophyll a concentration that have been previously observed in this region.

The relationship between phytoplankton concentration and light attenuation in ocean waters

NASA Technical Reports Server (NTRS)

Phinney, David A.; Yentsch, Charles S.

1986-01-01

The accuracy of chlorophyll estimates by ocean color algorithms is affected by the variability of particulate attenuation; the presence of dissolved organic matter; and the nonlinear inverse relationship between the attenuation coefficient, K, and chlorophyll. Data collected during the Warm Core Rings Program were used to model the downwelling light field and determine the impact of these errors. A possible mechanism for the nonlinearity of K and chlorophyll is suggested; namely, that changing substrate from nitrate-nitrogen to ammonium causes enhanced blue absorption by photosynthetic phytoplankton in oligotrophic surface waters.

Water residence time affecting phytoplankton blooms: study case in Ibitinga Reservoir (São Paulo, Brazil) using Landsat/TM images.

PubMed

Londe, L R; Novo, E M L M; Barbosa, C; Araujo, C A S

2016-05-03

Satellite images are an effective tool for the detection of phytoplankton blooms, since they cause striking changes in water color. Bloom intensity can be expressed in terms of chlorophyll-a concentration. Previous studies suggest the use of Landsat TM4/TM3 reflectance ratio to retrieve surface chlorophyll-a concentration from aquatic systems. In this study we assumed that a remote sensing trophic state index can be applied to investigate how changes in HRT along the hydrologic year affect the spatial distribution of the phytoplankton blooms at Ibitinga's reservoir surface. For that, we formulated two objectives: (1) apply a semi-empirical model which uses this reflectance ratio to map chlorophyll-a concentration at Ibitinga reservoir along the 2005 hydrologic year and (2) assess how changes in hydraulic residence time (HRT) affect the spatial distribution of phytoplankton blooms at Ibitinga Reservoir. The study site was chosen because previous studies reported seasonal changes in the reservoir limnology which might be related to the reservoir seasonality and hydrodynamics. Six Landsat/TM images were acquired over Ibitinga reservoir during 2005 and water flow measurements provided by the Brazilian Electric System National Operator - ONS were used to compute the reservoir´s residence time, which varied from 5.37 to 52.39 days during 2005. The HRT in the date of image acquisition was then compared to the distribution of chlorophyll-a in the reservoir. The results showed that the HRT increasing implies the increasing of the reservoir surface occupied by phytoplankton blooms.

Dynamics of the transition zone in coastal zone color scanner-sensed ocean color in the North Pacific during oceanographic spring

NASA Technical Reports Server (NTRS)

Glover, David M.; Wroblewski, J. S.; Mcclain, Charles R.

1994-01-01

A transition zone in phytoplankton concentration running across the North Pacific basin at 30 deg to 40 deg north latitude corresponds to a basin-wide front in surface chlorophyll observed in a composite of coastal zone color scanner (CZCS) images for May, June, and July 1979-1986. This transition zone with low chlorophyll to the south and higher chlorophyll to the north can be simulated by a simple model of the concentration of phytoplankton, zooplankton, and dissolved nutrient (nitrate) in the surface mixed layer of the ocean applied to the North Pacific basin for the climatological conditions during oceanographic springtime (May, June, and July). The model is initialized with a 1 deg x 1 deg gridded estimate of wintertime (February, March, and April) mixed layer nitrate concentrations calculated from an extensive nutrient database and a similarly gridded mixed layer depth data set. Comparison of model predictions with CZCS data provides a means of evaluating the dynamics of the transition zone. We conclude that in the North Pacific, away from major boundary currents and coastal upwelling zones, wintertime vertical mixing determines the total nutrient available to the plankton ecosystem in the spring. The transition zone seen in basin-scale CZCS images is a reflection of the geographic variation in the wintertime mixed layer depth and the nitracline, leading to a latitudinal gradient in phytoplankton chlorophyll.

Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts

USGS Publications Warehouse

Belnap, J.; Phillips, S.L.; Witwicki, D.L.; Miller, M.E.

2008-01-01

Biological soil crusts (BSCs) are an integral part of dryland ecosystems and often included in long-term ecological monitoring programs. Estimating moss and lichen cover is fairly easy and non-destructive, but documenting cyanobacterial level of development (LOD) is more difficult. It requires sample collection for laboratory analysis, which causes soil surface disturbance. Assessing soil surface stability also requires surface disturbance. Here we present a visual technique to assess cyanobacterial LOD and soil surface stability. We define six development levels of cyanobacterially dominated soils based on soil surface darkness. We sampled chlorophyll a concentrations (the most common way of assessing cyanobacterial biomass), exopolysaccharide concentrations, and soil surface aggregate stability from representative areas of each LOD class. We found that, in the laboratory and field, LOD classes were effective at predicting chlorophyll a soil concentrations (R2=68-81%), exopolysaccharide concentrations (R2=71%), and soil aggregate stability (R2=77%). We took representative photos of these classes to construct a field guide. We then tested the ability of field crews to distinguish these classes and found this technique was highly repeatable among observers. We also discuss how to adjust this index for the different types of BSCs found in various dryland regions.

Seasonal dynamics in colored dissolved organic matter in the Mediterranean Sea: Patterns and drivers

NASA Astrophysics Data System (ADS)

Xing, Xiaogang; Claustre, Hervé; Wang, Haili; Poteau, Antoine; D`Ortenzio, Fabrizio

2014-01-01

Two autonomous profiling “Bio-Argo” floats were deployed in the northwestern and eastern sub-basins of the Mediterranean Sea in 2008. They recorded at high vertical (1 m) and temporal (5 day) resolution, the vertical distribution and seasonal variation of colored dissolved organic matter (CDOM), as well as of chlorophyll-a concentration and hydrological variables. The CDOM standing stock presented a clear seasonal dynamics with the progressive summer formation and winter destruction of subsurface CDOM maxima (YSM, for Yellow Substance Maximum). It was argued that subsurface CDOM is a by-product of phytoplankton, based on two main characteristics, (1) the YSM was located at the same depth than the deep chlorophyll maximum (DCM) and (2) the CDOM increased in summer parallels the decline in chlorophyll-a. These observations suggested an indirect but tight coupling between subsurface CDOM and phytoplankton via microbial activity or planktonic foodweb interactions. Moreover, the surface CDOM variations observed both by floats and MODIS displayed different seasonal dynamics from what recorded at subsurface one. This implies that CDOM standing stock can be hardly detected by satellite. It is worthnoting that surface CDOM was found to be more related to the sea surface temperature (SST) than chlorophyll-a concentration, suggesting its physical origin, in contrast to the biological origin of YSM and subsurface standing stocks.

Chlorophyll extraction from suji leaf (Pleomele angustifolia Roxb.) with ZnCl2 stabilizer.

PubMed

Rahayuningsih, Edia; Pamungkas, Mukmin Sapto; Olvianas, Muhammad; Putera, Andreas Diga Pratama

2018-03-01

Suji ( Pleomele angustifolia Roxb .) leaves are a prominent source of chlorophyll and well-known for their ability to produce green color for food ingredients. However, chlorophyll is suspectible to color degradation at high temperature. Color degradation occurred because porphyrin loses magnesium in its ring and it can be avoided by adding zinc. The aim of this work was to investigate the combined effect of independent variables on chlorophyll extraction process using ZnCl 2 as a stabilizer. Suji leaves were blanched with boiling water for 2 min, Zn-chlorophyll synthesis was done by varying concentration of ZnCl 2 , Zn-chlorophyll extraction with ethanol, and UV-Vis spectrophotometry analysis of the final extracted solutions. A full three-level factorial design under response surface methodology was used to obtain the optimum condition of extraction process. The experimental data were analyzed by analysis of variance and fitted with second order polynomial equation. The coefficient of determination (R 2 ) was found to be 81.99%. The optimum operating conditions were obtained at pH 7, ZnCl 2 concentration of 700 ppm and temperature of 85 °C with desirability value of 1.0000. At the optimum conditions, the total chlorophyll content (TCC) was found to be 47.2975 mg/100 g fresh weight.

Subtropical Gyre Variability Observed by Ocean Color Satellites

NASA Technical Reports Server (NTRS)

McClain, Charles R.; Signorini, Sergio R.; Christian, James R.

2002-01-01

The subtropical gyres of the world are extensive, coherent regions that occupy about 40% of the surface of the earth. Once thought to be homogeneous and static habitats, there is increasing evidence that mid-latitude gyres exhibit substantial physical and biological variability on a variety of time scales. While biological productivity within these oligotrophic regions may be relatively small, their immense size makes their total contribution significant. Global distributions of dynamic height derived from satellite altimeter data, and chlorophyll concentration derived from satellite ocean color data, show that the dynamic center of the gyres, the region of maximum dynamic height where the thermocline is deepest, does not coincide with the region of minimum chlorophyll concentration. The physical and biological processes by which this distribution of ocean properties is maintained, and the spatial and temporal scales of variability associated with these processes, are analyzed using global surface chlorophyll-a concentrations, sea surface height, sea surface temperature and surface winds from operational satellite and meteorological sources, and hydrographic data from climatologies and individual surveys. Seasonal and interannual variability in the areal extent of the subtropical gyres are examined using 8 months (November 1996 - June 1997) of OCTS and nearly 5 years (September 1997 - June 02) of SeaWiFS ocean color data and are interpreted in the context of climate variability and measured changes in other ocean properties (i.e., wind forcing, surface currents, Ekman pumping, and vertical mixing). The North Pacific and North Atlantic gyres are observed to be shrinking over this period, while the South Pacific, South Atlantic, and South Indian Ocean gyres appear to be expanding.

Relation between Oceanographic parameters and Optical properties in 5 coastal areas of Southern Italy

NASA Astrophysics Data System (ADS)

Campanelli, Alessandra; Braga, Federica; Betti, Mattia; Cavalli, Rosa Maria; Grilli, Federica; Pascucci, Simone; Marini, Mauro

2014-05-01

In the framework of the CLAM-PHYM (Coasts-and-Lake-Assessment-and-Monitoring-by-Prisma-Hyperspectral-Mission) project it was carried out an oceanographic cruise (27/08-13/09/2010) along the coasts of southern Italy in order to analyze the physical, biochemical and optical properties of some coastal areas. The sampling areas are: the Gulf of Taranto, the Policoro area, the Cetraro Bay, the Gulf of Augusta and the Gulf of Gela. CTD profiles and reflectance measurements of the sea surface and along the water column with portable field spectroradiometers were collected. Water samples were also collected for the analysis of nutrients, chlorophyll-a and CDOM. These optically active substances interact with solar radiation along the water column through absorption and scattering phenomena. The collected data were analyzed to identify the relationship between the bio-optical concentrations of optically-active-substances and the surface reflectance spectra measured in situ; this relation, if reversed, can be used to map the concentrations of optically-active-substances from hyperspectral-satellite-data. Results stress high biological activity in the Gulf of Taranto and in the Gulf of Gela showing the highest values of chlorophyll-a and aCDOM440. These areas are characterized by the presence of important industrial and port sites. The Gela's gulf, where we found the highest concentrations of chlorophyll a and CDOM, is also characterized by the runoff of the Salso river increasing the biological activity. The correlations found in the Gulf of Taranto between Kd, chlorophyll a and aCDOM440 indicate that the high concentrations of CDOM are primarily due to phytoplankton rather than from terrestrial source. The Gulf of Taranto shows the best site among those investigated where to identify bio-optical relationships between the concentrations of optically active substances and the surface reflectance spectra measured in situ. The preliminary results encourage the combined use of physical, biochemical and optical properties to retrieve water quality parameters in order to improve the coastal areas monitoring.

Enzyme-assisted extraction of stabilized chlorophyll from spinach.

PubMed

Özkan, Gülay; Ersus Bilek, Seda

2015-06-01

Zinc complex formation with chlorophyll derivatives in spinach pulp was studied by adding 300ppm Zn(2+) for production of stable food colorant, followed by the heating at 110°C for 15min. Zinc complex formation increased at pH values of 7.0 or greater. Pectinex Ultra SP-L was selected for enzyme-assisted release of zinc-chlorophyll derivatives from spinach pulp. Effect of enzyme concentration (1-9%), treatment temperature (30-60°C), and time (30-210min) on total chlorophyll content (TCC) were optimized using response surface methodology. A quadratic regression model (R(2)=0.9486) was obtained from the experimental design. Optimum treatment conditions were 8% enzyme concentration, 45°C, and 30min, which yielded a 50.747mgTCC/100g spinach pulp. Enzymatic treatment was followed by solvent extraction with ethanol at a solvent-to-sample ratio of 2.5:1 at 60°C for 45min for the highest TCC recovery. Pretreatment with enzyme and extraction in ethanol resulted in 39% increase in Zn-chlorophyll derivative yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apparent Optical Properties in Waters Influenced by the Mississippi River

NASA Technical Reports Server (NTRS)

D'Sa, E.; Miller, R. L.; McKee, B. A.; Trzaska, R.

2002-01-01

In-water downwelling irradiance (E(sub d)) and upwelling radiance (L(sub u)) were measured in coastal waters influenced by the Mississippi River at wavelengths corresponding to SeaWiFS spectral bands in April of 2000. Results of derived apparent optical properties (AOP's) such as spectral diffise attenuation coefficient for downwelling irradiance (K(sub d)) suggest that they are mainly influenced by phytoplankton chlorophyll. Large variations in chlorophyll concentrations (0.2 to greater than 10 mg per cubic meters) correspond to variations in K(sub d) at 443 nm ranging from about 0.1 to greater than 1.5 per meter. Attenuation values at 443 nm generally peaked (or were minimal at 555 nm) at depths where chlorophyll concentrations were high. Above water remote sensing reflectance R(sub rs) (443) derived from E(sub d) and L(sub u) shows good agreement to surface chlorophyll. Ratios of remote sensing reflectance, R(sub rs)(443/R(sub rs)(555)versus chlorophyll suggests a potential for obtaining a suitable bio-optical algorithm for the region influenced by the Mississippi River.

Tracking upwind areas associated with enhanced chlorophyll-a concentrations to examine the impact of atmospheric deposition on phytoplankton production in the Sargasso and Mediterranean Seas

NASA Astrophysics Data System (ADS)

Kim, T. W.

2016-12-01

Transports of terrestrial materials through the atmosphere and their depositions influence ocean biogeochemistry. In particular, growth of phytoplankton in oligotrophic oceans may be stimulated by the atmospheric deposition of nutrients (e.g. reactive nitrogen species and iron). The Sargasso and Mediterranean Seas are two oligotrophic oceans that may show the enhancements in phytoplankton production by the atmospheric deposition, because their upwind areas include African deserts and urban areas of the United States and the Europe. To test this hypothesis, time series of chlorophyll-a concentration (from the Moderate Resolution Imaging Spectroradiometer) were combined with air mass back trajectory (from Hybrid Single Particle Lagrangian Integrated Trajectory Model) to perform the Concentration-Weighted Trajectory (CWT) receptor model. In this model, all individual endpoints of a single air mass back trajectory are associated with a chlorophyll-a concentration measured at the starting time of air mass back trajectory. The upwind areas showing relatively high CWT values represent they are mostly associated with enhanced chlorophyll-a concentration and contribute to phytoplankton production. We carried out the CWT in 65 and 188 stations for the Mediterranean and Saragossa Seas, respectively. The results showed relatively high CWT values in the North American and northern African continents. However, wind usually flows from these continents to ocean during cold months when chlorophyll-a concentrations are generally high. Thus the results appeared to largely originate from seasonal cycle of ocean mixed layer depth. To minimize the effect of seasonal variations, we divided chlorophyll-a concentrations by monthly climatology, which resulted in much reduced contrast in the CWT values between land and ocean areas. However, some upwind areas including the northern African desert regions still showed relatively high CWT values, maybe implying deposition-induced stimulation of phytoplankton production. We also performed CWT receptor model using sea surface temperature instead of chlorophyll-a concentration to see the effect of ocean mixed layer depth. These results will be included in the presentation.

Temporal variation in community composition, pigmentation, and Fv/Fm of desert cyanobacterial soil crusts

USGS Publications Warehouse

Bowker, M.A.; Reed, S.C.; Belnap, J.; Phillips, S.L.

2002-01-01

Summers on the Colorado Plateau (USA) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high UV and visible radiation. We investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. Representative surface cores were sampled at the ENE, WSW, and top microaspects of 20 individual soil crust pedicels at a single site in Canyonlands National Park, Utah, in spring and fall of 1999. Frequency of cyanobacterial taxa, pigment concentrations, and dark adapted quantum yield (Fv/Fm) were measured for each core. The frequency of major cyanobacterial taxa was lower in the fall compared to spring. The less-pigmented cyanobacterium Microcoleus vaginatus showed significant mortality when not in the presence of Nostoc spp. and Scytonema myochrous (Dillw.) Agardh. (both synthesizers of UV radiation-linked pigments) but had little or no mortality when these species were abundant. We hypothesize that the sunscreen pigments produced by Nostoc and Scytonema in the surface of crusts protect other, less-pigmented taxa. When fall and spring samples were compared, overall cyanobacterial frequency was lower in fall, while sunscreen pigment concentrations, chlorophyll a concentration, and Fv/Fm were higher in fall. The ratio of cyanobacterial frequency/chlorophyll a concentrations was 2-3 times lower in fall than spring. Because chlorophyll a is commonly used as a surrogate measure of soil cyanobacterial biomass, these results indicate that seasonality needs to be taken into consideration. In the fall sample, most pigments associated with UV radiation protection or repair were at their highest concentrations on pedicel tops and WSW microaspects, and at their lowest concentrations on ENE microaspects. We suggest that differential pigment concentrations between microaspects are induced by varying UV radiation dosage at the soil surface on these different microaspects.

Saharan Dust Deposition May Affect Phytoplankton Growth in the Mediterranean Sea at Ecological Time Scales

PubMed Central

Gallisai, Rachele; Peters, Francesc; Volpe, Gianluca; Basart, Sara; Baldasano, José Maria

2014-01-01

The surface waters of the Mediterranean Sea are extremely poor in the nutrients necessary for plankton growth. At the same time, the Mediterranean Sea borders with the largest and most active desert areas in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. We describe statistical correlations between dust deposition over the Mediterranean Sea and surface chlorophyll concentrations at ecological time scales. Aerosol deposition of Saharan origin may explain 1 to 10% (average 5%) of seasonally detrended chlorophyll variability in the low nutrient-low chlorophyll Mediterranean. Most of the statistically significant correlations are positive with main effects in spring over the Eastern and Central Mediterranean, conforming to a view of dust events fueling needed nutrients to the planktonic community. Some areas show negative effects of dust deposition on chlorophyll, coinciding with regions under a large influence of aerosols from European origin. The influence of dust deposition on chlorophyll dynamics may become larger in future scenarios of increased aridity and shallowing of the mixed layer. PMID:25333783

A comparison of ship and Coastal Zone Color Scanner mapped distribution of phytoplankton in the southeastern Bering Sea

NASA Technical Reports Server (NTRS)

Mcclain, C. R.; Sambrotto, R. N.; Ray, G. C.; Muller-Karger, F. E.

1990-01-01

Twenty-one Coastal Zone Color Scanner (CZCS) images of the southeastern Bering Sea are examined in order to map the near-surface distribution of phytoplankton during 1979 and 1980. The information is compared with the mesoscale (100-1000 km) distribution of phytoplankton inferred from pooled ship sampling obtained during the Processes and Resources of the Bering Shelf (PROBES) intensive field study during the late 1970s and early 1980s. The imagery indicates that open-water phytoplankton blooms occur first in late April in coastal waters, peak in early May over the middle shelf, and decay rapidly afterwards, reaching concentration minima in June in both regions. These patterns show that the earlier ship observations are valid for most of the eastern Bering shelf. A very tight correlation is found between the PROBES surface chlorophyll a concentrations and mean mixed-layer chlorophyll concentrations. The significant discrepancies between CZCS and ship-based chlorophyll estimates may be due to aliasing in time by the CZCS. It is concluded that neither satellite nor ship alone can do an adequate job of characterizing the physics or biological dynamics of the ocean.

Detection of surface algal blooms using the newly developed algorithm surface algal bloom index (SABI)

NASA Astrophysics Data System (ADS)

Alawadi, Fahad

2010-10-01

Quantifying ocean colour properties has evolved over the past two decades from being able to merely detect their biological activity to the ability to estimate chlorophyll concentration using optical satellite sensors like MODIS and MERIS. The production of chlorophyll spatial distribution maps is a good indicator of plankton biomass (primary production) and is useful for the tracing of oceanographic currents, jets and blooms, including harmful algal blooms (HABs). Depending on the type of HABs involved and the environmental conditions, if their concentration rises above a critical threshold, it can impact the flora and fauna of the aquatic habitat through the introduction of the so called "red tide" phenomenon. The estimation of chlorophyll concentration is derived from quantifying the spectral relationship between the blue and the green bands reflected from the water column. This spectral relationship is employed in the standard ocean colour chlorophyll-a (Chlor-a) product, but is incapable of detecting certain macro-algal species that float near to or at the water surface in the form of dense filaments or mats. The ability to accurately identify algal formations that sometimes appear as oil spill look-alikes in satellite imagery, contributes towards the reduction of false-positive incidents arising from oil spill monitoring operations. Such algal formations that occur in relatively high concentrations may experience, as in land vegetation, what is known as the "red-edge" effect. This phenomena occurs at the highest reflectance slope between the maximum absorption in the red due to the surrounding ocean water and the maximum reflectance in the infra-red due to the photosynthetic pigments present in the surface algae. A new algorithm termed the surface algal bloom index (SABI), has been proposed to delineate the spatial distributions of floating micro-algal species like for example cyanobacteria or exposed inter-tidal vegetation like seagrass. This algorithm was specifically modelled to adapt to the marine habitat through its inclusion of ocean-colour sensitive bands in a four-band ratio-based relationship. The algorithm has demonstrated high stability against various environmental conditions like aerosol and sun glint.

Ship and satellite observations of chlorophyll stocks in interacting cyclone-anticyclone eddy pairs in the western Gulf of Mexico

NASA Technical Reports Server (NTRS)

Biggs, Douglas, C.; Mueller-Karger, Frank E.

1994-01-01

When anticyclonic eddies shed by the Loop Current of the Gulf of Mexico reach the western margin of the gulf, they influence the surface circulation over the continental slope and rise. Of particular interest is the generation of cyclone (cold-core)-anticyclone (warm-core) pairs when aging Loop Current eddies interact with the continental margin. In this paper we describe the physical and biological characteristics of these cyclone-anticyclone pairs. Our objective was to determine how eddy pairs affect the distribution of phytoplankton in the region and how satellite ocean color measurements are applicable to tracing of the eddies. We present shipboard data collected between 1980 and 1982 on the hydrography, chlorophyll stocks, and nutrient concentrations of eddy pairs in the western Gulf of Mexico and compare these data with coastal zone color scanner (CZCS) images collected during the time frame of the cruises. Surface pigment concentrations followed a seasonal cycle, with low concentrations (0.05-0.1 mg m(exp -3)) found within cyclones and anticyclones from April through early November and higher concentrations (greater than 0.1 mg(exp -3)) found in the winter. CZCS pigment concentrations were locally high in the flow confluence of cyclone-anticyclone pairs. The CZCS imagery shows that some cyclone-anticyclone geometries transport high-chlorophyll shelf water seaward at least 100-200 km off-shelf.

The impact of multi-decadal sub-surface circulation changes on sea surface chlorophyll patterns in the tropical Pacific

NASA Astrophysics Data System (ADS)

Schollaert Uz, S.; Busalacchi, A. J.; Smith, T. M.; Evans, M. N.; Brown, C.; Hackert, E. C.; Wang, X.

2016-12-01

The tropical Pacific is a region of strong forcing where physical oceanography primarily controls biological variability over the seasonal to interannual time scales observed since dedicated ocean color satellite remote sensing began in 1997. To quantify how multi-decadal, climate-scale changes impact marine biological dynamics, we used the correlation with sea-surface temperature and height to reconstruct a 50-year time series of surface chlorophyll concentrations. The reconstruction demonstrates greatest skill away from the coast and within 10o of the equator where chlorophyll variance is greatest and primarily associated with El Niño Southern Oscillation (ENSO) dynamics and secondarily associated with decadal variability. We observe significant basin-wide differences between east and central Pacific events when the El Niño events are strong: chlorophyll increases with La Niña and decreases with El Niño, with larger declines east of 180o for remotely-forced east Pacific events and west of 180o for locally-forced central Pacific events. Chlorophyll variations also reflect the physical dynamics of Pacific decadal variability with small but significant differences between cool and warm eras: consistent with advection variability west of 180o and likely driven by subsurface changes in the nutricline depth between 110-140oW. Comparisons with output from a fully-coupled biogeochemical model support the hypothesis that this anomalous region is controlled by lower frequency changes in subsurface circulation patterns that transport nutrients to the surface. Basin-wide chlorophyll distributions exhibiting spatial heterogeneity in response to multi-decadal climate forcing imply similar long-term changes in phytoplankton productivity, with implications for the marine food web and the ocean's role as a carbon sink.

Potential Improvements to Remote Primary Productivity Estimation in the Southern California Current System

NASA Astrophysics Data System (ADS)

Jacox, M.; Edwards, C. A.; Kahru, M.; Rudnick, D. L.; Kudela, R. M.

2012-12-01

A 26-year record of depth integrated primary productivity (PP) in the Southern California Current System (SCCS) is analyzed with the goal of improving satellite net primary productivity (PP) estimates. The ratio of integrated primary productivity to surface chlorophyll correlates strongly to surface chlorophyll concentration (chl0). However, chl0 does not correlate to chlorophyll-specific productivity, and appears to be a proxy for vertical phytoplankton distribution rather than phytoplankton physiology. Modest improvements in PP model performance are achieved by tuning existing algorithms for the SCCS, particularly by empirical parameterization of photosynthetic efficiency in the Vertically Generalized Production Model. Much larger improvements are enabled by improving accuracy of subsurface chlorophyll and light profiles. In a simple vertically resolved production model, substitution of in situ surface data for remote sensing estimates offers only marginal improvements in model r2 and total log10 root mean squared difference, while inclusion of in situ chlorophyll and light profiles improves these metrics significantly. Autonomous underwater gliders, capable of measuring subsurface fluorescence on long-term, long-range deployments, significantly improve PP model fidelity in the SCCS. We suggest their use (and that of other autonomous profilers such as Argo floats) in conjunction with satellites as a way forward for improved PP estimation in coastal upwelling systems.

Vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

NASA Astrophysics Data System (ADS)

Sauzède, R.; Lavigne, H.; Claustre, H.; Uitz, J.; Schmechtig, C.; D'Ortenzio, F.; Guinet, C.; Pesant, S.

2015-10-01

In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms has led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted into phytoplankton biomass (i.e., chlorophyll a concentration) and size-based community composition (i.e., microphytoplankton, nanophytoplankton and picophytoplankton), using a method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over 5 decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from the surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available on open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition: http://doi.pangaea.de/10.1594/PANGAEA.844485

Short-Term Variability on the Scotian Shelf

NASA Astrophysics Data System (ADS)

Greenan, B.; Petrie, B.; Harrison, G.; Oakey, N.; Strain, P.

2002-12-01

The traditional view of the production cycle on the continental shelf of Nova Scotia features a spring bloom followed by a period of low production and a less intense fall bloom. The annual cycle of primary productivity thus has a large, low frequency component. However, there is increasing evidence that the production cycle has significant variability on shorter time scales. Physical, chemical and biological variability on the Scotian Shelf is examined on a daily to weekly timescale. This is accomplished through the use of a newly developed mooring platform (SeaHorse) that uses surface wave energy to enable the instrument to climb down the mooring wire and then float upwards while sampling the water column. This provides bi-hourly profiles of temperature, salinity, pressure and chlorophyll at one location over month-long periods. Results from the three-week deployment in October 2000 indicate a subsurface chlorophyll maximum below the pycnocline during the first part of the time series. An event occurred in mid-October during which the temperature, salinity and density iso-surfaces rose approximately 25 m. During this event, a small bloom, with peak chlorophyll concentrations of about 2 mg m-3 and duration of several days, began as nutrients were brought into the upper part of the water column by upwelling-favorable winds. SeaWiFS ocean color satellite images were valuable in providing a spatial context for chlorophyll concentrations, however, the lack of temporal resolution due to poor quality images means that this data set provided limited information for short-term chlorophyll variability. Gradient Richardson Numbers were estimated for 2 m vertical bins using SeaHorse CTD data and nearby ADCP current measurements. A trend of decreasing Ri in the ocean mixed layer with increasing surface wind stress is suggested.

Spatial variability of concentrations of chlorophyll a, dissolved organic matter and suspended particles in the surface layer of the Kara Sea in September 2011 from lidar data

NASA Astrophysics Data System (ADS)

Pelevin, V. V.; Zavjalov, P. O.; Belyaev, N. A.; Konovalov, B. V.; Kravchishina, M. D.; Mosharov, S. A.

2017-01-01

The article presents results of underway remote laser sensing of the surface water layer in continuous automatic mode using the UFL-9 fluorescent lidar onboard the R/V Akademik Mstislav Keldysh during cruise 59 in the Kara Sea in 2011. The description of the lidar, the approach to interpreting seawater fluorescence data, and certain methodical aspects of instrument calibration and measurement are presented. Calibration of the lidar is based on laboratory analysis of water samples taken from the sea surface during the cruise. Spatial distribution of chlorophyll a, total organic carbon and suspended matter concentrations in the upper quasi-homogeneous layer are mapped and the characteristic scales of the variability are estimated. Some dependencies between the patchiness of the upper water layer and the atmospheric forcing and freshwater runoff are shown.

Investigation of different coastal processes in Indonesian waters using SeaWiFS data

NASA Astrophysics Data System (ADS)

Hendiarti, Nani; Siegel, Herbert; Ohde, Thomas

2004-01-01

SeaWiFS data were applied to investigate coastal processes in Indonesian waters around the most populated island of Java. Coastal processes due to wind forcing were studied the first time using SeaWiFS-derived chlorophyll and TSM concentrations in combination with AVHRR-derived SST in the period from September 1997 to December 2001. Upwelling events were studied along the southern coast of Java during the southeast monsoon (June to September). Satellite-derived chlorophyll concentrations higher than 0.8 mg/ m3 and sea-surface temperatures lower than 28°C are indications of upwelling. Upwelling events influence the distribution and growth of phytoplankton and provide by that good feeding condition for zooplankton, larvae, juvenile and adult of pelagic fish. Coastal discharge into the western Java Sea contains organic and inorganic materials originating from different sources. Diffuse impacts, particularly from fish farms and aquaculture, as well as coastal erosion influence large coastal areas during the rainy season (December to March), and to a lesser extent during the dry season. Strong Citarum river discharge was observed during the transition phase from the rainy to the dry season (March and April), when the maximum amount of transported material reaches the sea. The river plume is evident from chlorophyll concentrations higher than 2.5 mg/ m3, and suspended particulate matter concentrations of more than 8 mg/dm3. The Sunda Strait is seasonally influenced by water transport from the Java Sea and from the Indian Ocean. The satellite data show that water transport from the Java Sea occurs during the pre-dominantly easterly winds period (June to September). This is characterized by warm water (SST higher than 29.5°C) and chlorophyll concentrations higher than 0.5 mg/ m3. This water transport influences the fish abundance in the Sunda Strait. High fish catches coincide with the presence of Java Sea water, while the surface currents lead to the migration of pelagic fish. Conversely, during the dominant westerly winds period, oceanic waters from the Indian Ocean with low chlorophyll concentrations influence the Sunda Strait water.

Ocean Data Acquisition System

NASA Technical Reports Server (NTRS)

Johnson, B.; Cavanaugh, J.; Smith, J.; Esaias, W.

1988-01-01

The Ocean Data Acquisition System (ODAS) is a low cost instrument with potential commercial application. It is easily mounted on a small aircraft and flown over the coastal zone ocean to remotely measure sea surface temperature and three channels of ocean color information. From this data, chlorophyll levels can be derived for use by ocean scientists, fisheries, and environmental offices. Data can be transmitted to shipboard for real-time use with sea truth measurements, ocean productivity estimates and fishing fleet direction. The aircraft portion of the system has two primary instruments: an IR radiometer to measure sea surface temperature and a three channel visible spectro-radiometer for 460, 490, and 520 nm wavelength measurements from which chlorophyll concentration can be derived. The aircraft package contains a LORAN-C unit for aircraft location information, clock, on-board data processor and formatter, digital data storage, packet radio terminal controller, and radio transceiver for data transmission to a ship. The shipboard package contains a transceiver, packet terminal controller, data processing and storage capability, and printer. Both raw data and chlorophyll concentrations are available for real-time analysis.

Chlorophyll a Covalently Bonded to Organo-Modified Translucent Silica Xerogels: Optimizing Fluorescence and Maximum Loading.

PubMed

García-Sánchez, M A; Serratos, I N; Sosa, R; Tapia-Esquivel, T; González-García, F; Rojas-González, F; Tello-Solís, S R; Palacios-Enriquez, A Y; Esparza Schulz, J M; Arrieta, A

2016-07-22

Chlorophyll is a pyrrolic pigment with important optical properties, which is the reason it has been studied for many years. Recently, interest has been rising with respect to this molecule because of its outstanding physicochemical properties, particularly applicable to the design and development of luminescent materials, hybrid sensor systems, and photodynamic therapy devices for the treatment of cancer cells and bacteria. More recently, our research group has been finding evidence for the possibility of preserving these important properties of substrates containing chlorophyll covalently incorporated within solid pore matrices, such as SiO₂, TiO₂ or ZrO₂ synthesized through the sol-gel process. In this work, we study the optical properties of silica xerogels organo-modified on their surface with allyl and phenyl groups and containing different concentrations of chlorophyll bonded to the pore walls, in order to optimize the fluorescence that these macrocyclic species displays in solution. The intention of this investigation was to determine the maximum chlorophyll a concentration at which this molecule can be trapped inside the pores of a given xerogel and to ascertain if this pigment remains trapped as a monomer, a dimer, or aggregate. Allyl and phenyl groups were deposited on the surface of xerogels in view of their important effects on the stability of the molecule, as well as over the fluorescence emission of chlorophyll; however, these organic groups allow the trapping of either chlorophyll a monomers or dimers. The determination of the above parameters allows finding the most adequate systems for subsequent in vitro or in vivo studies. The characterization of the obtained xerogels was performed through spectroscopic absorption, emission and excitation spectra. These hybrid systems can be employed as mimics of natural systems; the entrapment of chlorophyll inside pore matrices indicates that it is possible to exploit some of the most physicochemical properties of trapped chlorophyll for diverse technological applications. The data herein collected suggest the possibility of applying the developed methodology to other active, captive molecules in order to synthesize new hybrid materials with optimized properties, suitable to be applied in diverse technological fields.

Competition for spectral irradiance between epilimnetic optically active dissolved and suspended matter and phytoplankton in the metalimnion. Consequences for limnology and chemistry.

PubMed

Bracchini, Luca; Dattilo, Arduino Massimo; Falcucci, Margherita; Hull, Vincent; Tognazzi, Antonio; Rossi, Claudio; Loiselle, Steven Arthur

2011-06-01

In deep lakes, water column stratification isolates the surface water from the deeper bottom layers, creating a three dimensional differentiation of the chemical, physical, biological and optical characteristics of the waters. Chromophoric dissolved organic matter (CDOM) and total suspended solids (TSS) play an important role in the attenuation of ultraviolet and photosynthetically active radiation. In the present analysis of spectral irradiance, we show that the wavelength composition of the metalimnetic visible irradiance was influenced by epilimnetic spatial distribution of CDOM. We found a low occurrence of blue-green photons in the metalimnion where epilimnetic concentrations of CDOM are high. In this field study, the spatial variation of the spectral irradiance in the metalimnion correlates with the observed metalimnetic concentrations of chlorophyll a as well as chlorophyll a : chlorophyll b/c ratios. Dissolved oxygen, pH, and nutrients trends suggest that chlorophyll a concentrations were representative of the phytoplankton biomass and primary production. Thus, metalimnetic changes of spectral irradiance may have a direct impact on primary production and an indirect effect on the spatial trends of pH, dissolved oxygen, and inorganic nutrients in the metalimnion.

Assimilation of seasonal chlorophyll and nutrient data into an adjoint three-dimensional ocean carbon cycle model: Sensitivity analysis and ecosystem parameter optimization

NASA Astrophysics Data System (ADS)

Tjiputra, Jerry F.; Polzin, Dierk; Winguth, Arne M. E.

2007-03-01

An adjoint method is applied to a three-dimensional global ocean biogeochemical cycle model to optimize the ecosystem parameters on the basis of SeaWiFS surface chlorophyll observation. We showed with identical twin experiments that the model simulated chlorophyll concentration is sensitive to perturbation of phytoplankton and zooplankton exudation, herbivore egestion as fecal pellets, zooplankton grazing, and the assimilation efficiency parameters. The assimilation of SeaWiFS chlorophyll data significantly improved the prediction of chlorophyll concentration, especially in the high-latitude regions. Experiments that considered regional variations of parameters yielded a high seasonal variance of ecosystem parameters in the high latitudes, but a low variance in the tropical regions. These experiments indicate that the adjoint model is, despite the many uncertainties, generally capable to optimize sensitive parameters and carbon fluxes in the euphotic zone. The best fit regional parameters predict a global net primary production of 36 Pg C yr-1, which lies within the range suggested by Antoine et al. (1996). Additional constraints of nutrient data from the World Ocean Atlas showed further reduction in the model-data misfit and that assimilation with extensive data sets is necessary.

Primary productivity and its variability in the equatorial South China Sea during the northeast monsoon

NASA Astrophysics Data System (ADS)

Ooi, S. H.; Samah, A. A.; Braesicke, P.

2013-08-01

Near coastal areas of the equatorial South China Sea (SCS) are one of the world's regions with highest primary productivity (phytoplankton growth). Concentrations of phytoplankton in the SCS depend significantly on atmospheric forcings and the oceanic state, in particular during the northeast (winter) monsoon season from November to March. Aided by new ocean-observing satellite data, we present a climatological overview of recent surface atmospheric and oceanic features in the equatorial SCS during the northeast monsoon to identify the dominant air-sea processes influencing and modulating the primary productivity of the region. Measured chlorophyll a concentrations are used as a proxy for phytoplankton amounts and the spatial and temporal variations are characterized according to meteorological conditions. Converging northeasterly surface winds support high chlorophyll a concentrations along East Malaysia's coastline in conjunction with a continual nutrient supply from the bottom of the continental shelf by vertical mixing. The mixing can be enhanced due to increased turbulence by wind-generated high waves when they approach shallow water from the deep basin during strong cold surges and monsoon disturbances. Intraseasonal variability during the winter monsoon is characterized by a coastal increase of chlorophyll a starting in November and peaking in January. A general decrease is observed in March. Interannual variability of chlorophyll a concentrations is influenced by ENSO (due to the known modulation of cold surge occurrences), with decreases during El Niño and increases during La Niña in early winter along the shore of East Malaysia. As an example, we discuss an enhanced phytoplankton growth event that occurred due to a typical cold surge-induced Borneo vortex event in January 2010.

Visible foliar injury caused by ozone alters the relationship between SPAD meter readings and chlorophyll concentrations in cutleaf coneflower.

PubMed

Neufeld, Howard S; Chappelka, Arthur H; Somers, Greg L; Burkey, Kent O; Davison, Alan W; Finkelstein, Peter L

2006-03-01

The ability of the SPAD-502 chlorophyll meter to quantify chlorophyll amounts in ozone-affected leaves of cutleaf coneflower (Rudbeckia laciniata var. digitata) was assessed in this study. When relatively uninjured leaves were measured (percent leaf area affected by stipple less than 6%), SPAD meter readings were linearly related to total chlorophyll with an adjusted R (2) of 0.84. However, when leaves with foliar injury (characterized as a purple to brownish stipple on the upper leaf surface affecting more than 6% of the leaf area) were added, likelihood ratio tests showed that it was no longer possible to use the same equation to obtain chlorophyll estimations for both classes of leaves. Either an equation with a common slope or a common intercept was necessary. We suspect several factors are involved in altering the calibration of the SPAD meter for measuring chlorophyll amounts in visibly ozone-injured leaves, with the most likely being changes in either light absorption or scattering resulting from tissue necrosis.

Leaf Surface Effects on Retrieving Chlorophyll Content from Hyperspectral Remote Sensing

NASA Astrophysics Data System (ADS)

Qiu, Feng; Chen, JingMing; Ju, Weimin; Wang, Jun; Zhang, Qian

2017-04-01

Light reflected directly from the leaf surface without entering the surface layer is not influenced by leaf internal biochemical content. Leaf surface reflectance varies from leaf to leaf due to differences in the surface roughness features and is relatively more important in strong absorption spectral regions. Therefore it introduces dispersion of data points in the relationship between biochemical concentration and reflectance (especially in the visible region). Separation of surface from total leaf reflection is important to improve the link between leaf pigments content and remote sensing data. This study aims to estimate leaf surface reflectance from hyperspectral remote sensing data and retrieve chlorophyll content by inverting a modified PROSPECT model. Considering leaf surface reflectance is almost the same in the visible and near infrared spectral regions, a surface layer with a reflectance independent of wavelength but varying from leaf to leaf was added to the PROSPECT model. The specific absorption coefficients of pigments were recalibrated. Then the modified model was inverted on independent datasets to check the performance of the model in predicting the chlorophyll content. Results show that differences in estimated surface layer reflectance of various species are noticeable. Surface reflectance of leaves with epicuticular waxes and trichomes is usually higher than other samples. Reconstruction of leaf reflectance and transmittance in the 400-1000 nm wavelength region using the modified PROSPECT model is excellent with low root mean square error (RMSE) and bias. Improvements for samples with high surface reflectance (e.g. maize) are significant, especially for high pigment leaves. Moreover, chlorophyll retrieved from inversion of the modified model is consequently improved (RMSE from 5.9-13.3 ug/cm2 with mean value 8.1 ug/cm2, while mean correlation coefficient is 0.90) compared to results of PROSPECT-5 (RMSE from 9.6-20.2 ug/cm2 with mean value 13.1 ug/cm2, while mean correlation coefficient is 0.81). Underestimation of high chlorophyll content, which is due to underestimation of reflectance in the visible region of PROSPECT, is partially corrected or alleviated. Improvements are particularly noticeable for leaves with high surface reflectance or high chlorophyll content, which both lead to large proportions of surface reflectance to the total leaf reflectance.

Event-scale relationships between surface velocity, temperature and chlorophyll in the coastal ocean, as seen by satellite

NASA Technical Reports Server (NTRS)

Strub, P. Ted

1991-01-01

The overall goal of this project was to increase our understanding of processes which determine the temporally varying distributions of surface chlorophyll pigment concentration and surface temperature in the California Current System (CCS) on the time-scale of 'events', i.e., several days to several weeks. We also proposed to investigate seasonal and regional differences in these events. Additionally, we proposed to evaluate methods of estimating surface velocities and horizontal transport of pigment and heat from sequences of AVHRR and CZCS images. The four specific objectives stated in the original proposal were to: (1) test surface current estimates made from sequences of both SST and color images using variations of the statistical method of Emery et al. (1986) and estimate the uncertainties in these satellite-derived surface currents; (2) characterize the spatial and temporal relationships of chlorophyll and temperature in rapidly evolving features for which adequate imagery exist and evaluate the contribution of these events to monthly and seasonal averages; (3) use the methods tested in (1) to determine the nature of the velocity fields in the CCS; and (4) compare the currents, temperature, and currents in different seasons and in different geographic regions.

Enhancement of phytoplankton chlorophyll by submesoscale frontal dynamics in the North Pacific Subtropical Gyre.

PubMed

Liu, Xiao; Levine, Naomi M

2016-02-28

Subtropical gyres contribute significantly to global ocean productivity. As the climate warms, the strength of these gyres as a biological carbon pump is predicted to diminish due to increased stratification and depleted surface nutrients. We present results suggesting that the impact of submesoscale physics on phytoplankton in the oligotrophic ocean is substantial and may either compensate or exacerbate future changes in carbon cycling. A new statistical tool was developed to quantify surface patchiness from sea surface temperatures. Chlorophyll concentrations in the North Pacific Subtropical Gyre were shown to be enhanced by submesoscale frontal dynamics with an average increase of 38% (maximum of 83%) during late winter. The magnitude of this enhancement is comparable to the observed decline in chlorophyll due to a warming of ~1.1°C. These results highlight the need for an improved understanding of fine-scale physical variability in order to predict the response of marine ecosystems to projected climate changes.

Enhancement of phytoplankton chlorophyll by submesoscale frontal dynamics in the North Pacific Subtropical Gyre

NASA Astrophysics Data System (ADS)

Liu, Xiao; Levine, Naomi M.

2016-02-01

Subtropical gyres contribute significantly to global ocean productivity. As the climate warms, the strength of these gyres as a biological carbon pump is predicted to diminish due to increased stratification and depleted surface nutrients. We present results suggesting that the impact of submesoscale physics on phytoplankton in the oligotrophic ocean is substantial and may either compensate or exacerbate future changes in carbon cycling. A new statistical tool was developed to quantify surface patchiness from sea surface temperatures. Chlorophyll concentrations in the North Pacific Subtropical Gyre were shown to be enhanced by submesoscale frontal dynamics with an average increase of 38% (maximum of 83%) during late winter. The magnitude of this enhancement is comparable to the observed decline in chlorophyll due to a warming of ~1.1°C. These results highlight the need for an improved understanding of fine-scale physical variability in order to predict the response of marine ecosystems to projected climate changes.

Ocean color, a three component system?

NASA Technical Reports Server (NTRS)

Yentsch, C. S.; Owen, W. P.

1972-01-01

This study measures the concentrations of phytoplankton chlorophyll and yellow substance in the coastal waters of the Gulf of Maine. Sea surface observations attempt to delineate the principal biochemical parameters responsible for sea surface color. It is shown that the reddish-brown water changed to a blue-green in the open gulf.

Spatial variation of biogenic sulfur in the south Yellow Sea and the East China Sea during summer and its contribution to atmospheric sulfate aerosol.

PubMed

Zhang, Sheng-Hui; Yang, Gui-Peng; Zhang, Hong-Hai; Yang, Jian

2014-08-01

Spatial distributions of biogenic sulfur compounds including dimethylsulfide (DMS), dissolved and particulate dimethylsulfoniopropionate (DMSPd and DMSPp) were investigated in the South Yellow Sea (SYS) and the East China Sea (ECS) in July 2011. The concentrations of DMS and DMSPp were significantly correlated with the levels of chlorophyll a in the surface water. Simultaneously, relatively high ratio values of DMSP/chlorophyll a and DMS/chlorophyll a occurred in the areas where the phytoplankton community was dominated by dinoflagellates. The DMSPp and chlorophyll a size-fractionation showed that larger nanoplankton (5-20 μm) was the most important producer of DMSPp in the study area. The vertical profiles of DMS and DMSP were characterized by a maximum at the upper layer and the bottom concentrations were also relatively higher compared with the overlying layer of the bottom. In addition, a positive linear correlation was observed between dissolved dimethylsulfoxide (DMSOd) and DMS concentrations in the surface waters. The sea-to-air fluxes of DMS in the study area were estimated to be from 0.03 to 102.35 μmol m(-2) d(-1) with a mean of 16.73 μmol m(-2) d(-1) and the contribution of biogenic non-sea-salt SO4(2-) (nss-SO4(2-)) to the measured total nss-SO4(2-) in the atmospheric aerosol over the study area varied from 1.42% to 30.98%, with an average of 8.2%. Copyright © 2014 Elsevier B.V. All rights reserved.

Detection of deep water formation from remote sensing chlorophyll in the NW Mediterranean Sea

NASA Astrophysics Data System (ADS)

Bernardello, Raffaele; Bahamon, Nixon; Ahumada, Miguel-Angel; Martin, Adrian; Henson, Stephanie

2015-04-01

The Northwestern Mediterranean Sea is one of the few regions in the world where Deep Water Formation (DWF) occurs. During wintertime cold and dry winds that typically occur in strong bursts lasting a few days, are able to erode the near-surface stability over this area, exposing the weakly stratified underwaters and initiate a phase of violent mixing and deep convection. DWF is not a steady-state process that recurs every year. Variations in wind stress and heat flux over the winter can induce a marked interannual variability: during some years the process is specially intense and completely absent during others. The extent of the area over which DWF occurs is also uncertain. The interannual variability of the DWF process is also associated to the variability in the seasonal phytoplankton dynamics over the area. The extent of the vertical mixing set the total amount of nutrients available for the phytoplankton during the following spring bloom. However, before the bloom, when deep convection is still active, surface chlorophyll (an index for phytoplankton biomass) is vertically diluted showing low surface concentration. The occurrence of these patches of anomalously low chlorophyll concentration can, in principle, be associated to the presence of active deep convection. In this study we investigate the possibility of exploiting such association in order to quantify the duration of deep convection and the extent of the area over which it occurs. These goals will be achieved through the analysis of remote sensing chlorophyll data and in-situ Argo-floats profiles.

Influence of solar radiation absorbed by phytoplankton on the thermal structure and circulation of the tropical Atlantic Ocean

NASA Astrophysics Data System (ADS)

Frouin, Robert; Ueyoshi, Kyozo; Kampel, Milton

2007-09-01

Numerical experiments conducted with an ocean general ocean circulation model reveal the potential influence of solar radiation absorbed by phytoplankton on the thermal structure and currents of the Tropical Atlantic Ocean. In the model, solar radiation penetration is parameterized explicitly as a function of chlorophyll-a concentration, the major variable affecting water turbidity in the open ocean. Two types of runs are performed, a clear water (control) run with a constant minimum chlorophyll-a concentration of 0.02 mgm -3, and a turbid water (chlorophyll) run with space- and time-varying chlorophyll-a concentration from satellite data. The difference between results from the two runs yields the biological effects. In the chlorophyll run, nutrients and biology production are implicitly taken into account, even though biogeochemical processes are not explicitly included, since phytoplankton distribution, prescribed from observations, is the result of those processes. Due to phytoplankton-radiation forcing, the surface temperature is higher by 1-2 K on average annually in the region of the North Equatorial current, the Northern part of the South Equatorial current, and the Caribbean system, and by 3-4 K in the region of the Guinea current. In this region, upwelling is reduced, and heat trapped in the surface layers by phytoplankton is not easily removed. The surface temperature is lower by 1 K in the Northern region of the Benguela current, due to increased upwelling. At depth, the equatorial Atlantic is generally cooler, as well as the eastern part of the tropical basin (excluding the region of the sub-tropical gyres). The North and South equatorial currents, as well as the Equatorial undercurrent, are enhanced by as much as 3-4 cms -1, and the circulation of the subtropical gyres is increased. Pole-ward heat transport is slightly reduced North of 35°N, suggesting that phytoplankton, by increasing the horizontal return flow in the subtropical region, may exert a cooling influence on higher latitude regions. The findings indicate that biology-induced buoyancy plays a significant role, in an indirect if not direct way, in the variability of the Tropical Atlantic Ocean, with consequences on atmospheric circulation and climate.

Surface-water-quality assessment of the Upper Illinois River basin in Illinois, Indiana, and Wisconsin; cross-sectional and depth variation of water-quality constituents and properties in the Upper Illinois River basin, 1987-88

USGS Publications Warehouse

Marron, Donna C.; Blanchard, Stephen F.

1995-01-01

Data on water velocity, temperature, specific con- ductance, pH, dissolved oxygen concentration, chlorophyll concentration, suspended sediment con- centration, fecal-coliform counts, and the percen- tage of suspended sediment finer than 62 micrometers ranged up to 21 percent; and cross-section coefficients of variation of the concentrations of suspended sediment, fecal coliform, and chlorophyll ranged from 7 to 115 percent. Midchannel measure- ments of temperature, specific conductance, and pH were within 5 percent of mean cross-sectional values of these properties at the eight sampling sites, most of which appear well mixed because of the effect of dams and reservoirs. Measurements of the concentration of dissolved oxygen at various cross- section locations and at variable sampling depths are required to obtain a representative value of this constituent at these sites. The large varia- bility of concentrations of chlorophyll and suspended sediment, and fecal-coliform counts at the eight sampling sites indicates that composite rather than midchannel or mean values of these constituents are likely to be most representative of the channel cross section.

Changes in growth, leaf anatomy and pigment concentrations in pea under modulated UV-B field treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Day, T.A.; Howells, B.W.; Ruhland, C.T.

1995-06-01

In growth-chamber and greenhouse studies, garden pea is typically quite sensitive to enhanced UV-B radiation (280-320 nm). We assessed whether growth of pea was reduced under more ecologically relevant UV-B enhancements by employing modulated field lampbanks simulating 0, 16 or 24% ozone depletion. We also examined if these UV-B treatments altered leaf anatomy and concentrations of chlorophyll and UV-B-absorbing compounds, and whether this was dependent on leaf age. We used Pisum sativum mutant Argenteum which has an easily detachable epidermis that allowed us to compare concentrations in epidermal and mesophyll tissues. There were no significant UV-B effects on whole-plant growth.more » Of the 15 leaf-level parameters we examined, UV-B had a strong effect on only two parameters: the ratio of UV-B-absorbing compounds to chlorophyll (which increased with UV-B dose), and stomatal density of the adaxial surface (which decreased with UV-B dose). Chlorophyll concentrations tended to decrease, while the proportion of UV-B-absorbing compounds in the adaxial epidermis tended to increase with UV-B dose (p = 0.11 for both). In contrast to UV-B effects, we found strong leaf-age effects on nearly all parameters except the ratio of UV-B-absorbing compounds to chlorophyll, which remained relatively constant with leaf age.« less

Use of thematic mapper imagery to assess water quality, trophic state, and macrophyte distributions in Massachusetts lakes

USGS Publications Warehouse

Waldron, Marcus C.; Steeves, Peter A.; Finn, John T.

2001-01-01

During the spring and summer of 1996, 1997, and 1998, measurements of phytoplankton- chlorophyll concentration, Secchi disk transparency, and color were made at 97 Massachusetts lakes within 24 hours of Landsat Thematic Mapper imaging of the lakes in an effort to assess water quality and trophic state. Spatial distributions of floating, emergent, and submerged macrophytes were mapped in 49 of the lakes at least once during the 3-year period. The maps were digitized and used to assign pixels in the thematic mapper images to one of four vegetation cover classes-open water, 1-50 percent floating-and-emergent-vegetation cover, 51-100 percent floating-and-emergent-vegetation cover, and submerged vegetation at any density. The field data were collected by teams of U.S. Geological Survey and Massachusetts Department of Environmental Management staff and by 76 volunteers. Side-by-side sampling by U.S. Geological Survey and volunteer field teams resulted in statistically similar chlorophyll determinations, Secchi disk readings, and temperature measurements, but concurrent color determinations were not similar, possibly due to contamination of sample bottles issued to the volunteers.Attempts to develop predictive relations between phytoplankton-chlorophyll concentration, Secchi disk transparency, lake color, dissolved organic carbon, and various combinations of thematic mapper bands 1, 2, 3, and 4 digital numbers were unsuccessful, primarily because of the extremely low concentrations of chlorophyll in the lakes studied, and also because of the highly variable dissolved organic carbon concentrations.Predictive relations were developed between Secchi disk transparency and phytoplankton-chlorophyll concentration, and between color and dissolved organic carbon concentration. Phytoplankton-chlorophyll concentration was inversely correlated with Secchi disk transparency during all three sampling periods. The relations were very similar in 1996 and 1997 and indicated that 62 to 67 percent of the variability in Secchi disk transparency could be explained by the chlorophyll concentration. Analysis of color and dissolved organic carbon concentrations in water samples collected by U.S. Geological Survey field teams in 1996-98 indicated that 91 percent of the variance in color in Massachusetts lakes can be explained by variations in dissolved organic carbon.Areas of open-water, submerged vegetation, and two surface-vegetation-cover classes predicted from Thematic Mapper images acquired in the summer of 1996 closely matched the areas observed in a set of field observations. However, the same analysis applied to a set of data acquired in the summer of 1997 resulted in somewhat less reliable predictions, and an attempt to predict 1996 vegetation-cover areas using the relations developed in the 1997 analysis was unsuccessful.

Study on changing rules of chlorophyll concentration of detached canola leaves

NASA Astrophysics Data System (ADS)

Huang, Min; Feng, Lei; He, Yong; Zhu, Zheyan

2006-09-01

Chlorophyll is important for crops. The chlorophyll concentration is commonly used as the principal symptom of senescence. The objective of this paper was to study the relationship between the chlorophyll concentration and the time after the leaves being separated from the canola to confirm the detached leaves' senescence rate. The chlorophyll meter (SPAD meter) has been used in chlorophyll concentration measurement of fruit trees, sugar maple leaves in forest, corn with varying color and so on. In the experiment, a Minolta SPAD-502 chlorophyll Meter was used for measuring the chlorophyll concentration after picking off the canola leaves for 0 hour, 5 hours, 15 hours, 25 hours and 40 hours, and 25 samples were measured. As a result, the leaf senescence rules were found by observing the changing curves of the leaves' SPAD values. The original detached canola leaves were divided into three kinds of samples, and a certain senescence rule was found for each kind of samples. The results could provide good methods support to delay leaf senescence.

Biooptical variability in the Greenland Sea observed with the Multispectral Airborne Radiometer System (MARS)

NASA Technical Reports Server (NTRS)

Mueller, James L.; Trees, Charles C.

1989-01-01

A site-specific ocean color remote sensing algorithm was developed and used to convert Multispectral Airborne Radiometer System (MARS) spectral radiance measurements to chlorophyll-a concentration profiles along aircraft tracklines in the Greenland Sea. The analysis is described and the results given in graphical or tabular form. Section 2 describes the salient characteristics and history of development of the MARS instrument. Section 3 describes the analyses of MARS flight segments over consolidated sea ice, resulting in a set of altitude dependent ratios used (over water) to estimate radiance reflected by the surface and atmosphere from total radiance measured. Section 4 presents optically weighted pigment concentrations calculated from profile data, and spectral reflectances measured in situ from the top meter of the water column; this data was analyzed to develop an algorithm relating chlorophyll-a concentrations to the ratio of radiance reflectances at 441 and 550 nm (with a selection of coefficients dependent upon whether significant gelvin presence is implied by a low ratio of reflectances at 410 and 550 nm). Section 5 describes the scaling adjustments which were derived to reconcile the MARS upwelled radiance ratios at 410:550 nm and 441:550 nm to in situ reflectance ratios measured simultaneously on the surface. Section 6 graphically presents the locations of MARS data tracklines and positions of the surface monitoring R/V. Section 7 presents stick-plots of MARS tracklines selected to illustrate two-dimensional spatial variability within the box covered by each day's flight. Section 8 presents curves of chlorophyll-a concentration profiles derived from MARS data along survey tracklines. Significant results are summarized in Section 1.

Relative importance of habitat filtering and limiting similarity on species assemblages of alpine and subalpine plant communities.

PubMed

Takahashi, Koichi; Tanaka, Saeka

2016-11-01

This study examined how habitat filtering and limiting similarity affect species assemblages of alpine and subalpine plant communities along a slope gradient on Mt. Norikura in central Japan. Plant traits (plant height, individual leaf area, specific leaf area (SLA), leaf linearity, leaf nitrogen and chlorophyll concentrations) and abiotic environmental factors (elevation, slope inclination, ground surface texture, soil water, soil pH, soil nutrient concentrations of NH 4 -N and NO 3 -N) were examined. The metrics of variance, range, kurtosis and the standard deviation of neighbor distance divided by the range of traits present (SDNDr) were calculated for each plant trait to measure trait distribution patterns. Limiting similarity was detected only for chlorophyll concentration. By contrast, habitat filtering was detected for individual leaf area, SLA, leaf linearity, chlorophyll concentration. Abiotic environmental factors were summarized by the principal component analysis (PCA). The first PCA axis positively correlated with elevation and soil pH, and negatively correlated with sand cover, soil water, NH 4 -N and NO 3 -N concentrations. High values of the first PCA axis represent the wind-exposed upper slope with lower soil moisture and nutrient availabilities. Plant traits changed along the first PCA axis. Leaf area, SLA and chlorophyll concentration decreased, and leaf linearity increased with the first PCA axis. This study showed that the species assemblage of alpine and subalpine plants was determined mainly by habitat filtering, indicating that abiotic environmental factors are more important for species assemblage than interspecific competition. Therefore, only species adapting to abiotic environments can distribute to these environments.

MJO (Madden-Julian Oscillation) Analysis of the Chlorophyll-a Distribution in Western Waters Bengkulu

NASA Astrophysics Data System (ADS)

Haryanto, Y. D.; Fitrianti, N.; Hartoko, A.; Anggoro, S.; Zainuri, M.

2017-02-01

The global phenomenon Madden-Julian Oscillation (MJO) is one of the dominant oscillation in the equatorial region of the Indian Ocean that oscillates between 30-60 days and experience the process of convection movement from west to east. MJO has a correlation of high intensity rainfall of the area in its path. During his journey eastward, the MJO is influenced by the position of the sun. When the sun in the equatorial MJO moves straight east. Meanwhile, when the position of the sun in the south of the equator, MJO shifted slightly to the south of the equator, known as the propagation of the south-east (south-eastern propagation). When the position of the sun is in the north of the equator, MJO shifted slightly to the north of the equator, known as the propagation of the north-east (north-east of propagation). Waters west of Bengkulu has a huge potential in the fisheries sector, which is situated overlooking the Indian Ocean. The phenomenon MJO influence on rainfall, sea surface temperature, and the concentration of chlorophyll-a. This study aims to look at the temporal distribution of sea surface temperature and chlorophyll-a and decide how MJO relationship with SST and precipitation conditions and increasing the amount of chlorophyll during the phase of the MJO in Bengkulu waters. The dataset used is data of chlorophyll-a which download in oceancolor.gfsc.nasa.gov , sea surface temperature data is used is a model of Kaplan Extended V2, RMM1 index data and RMM2 on www.bom.gov.au and rainfall data of Bengkulu region. The method used is descriptive statistical methods, Conditional Probability and logistics regression. From the above explanation can be said that there is a relationship between the incidence of MJO by the number of chlorophyll-a. Odds the addition of chlorophyll-a have a linear relationship with the duration of the incident MJO in Bengkulu, odds increase the amount of chlorophyll-a in Bengkulu region reaches a threshold value of 0.5, it means that the length occurrence MJO able to identify increasing the number of chlorophyll-a in Bengkulu.

Vertical distribution of phytoplankton communities in open ocean: An assessment based on surface chlorophyll

NASA Astrophysics Data System (ADS)

Uitz, Julia; Claustre, Hervé; Morel, André; Hooker, Stanford B.

2006-08-01

The present study examines the potential of using the near-surface chlorophyll a concentration ([Chla]surf), as it can be derived from ocean color observation, to infer the column-integrated phytoplankton biomass, its vertical distribution, and ultimately the community composition. Within this context, a large High-Performance Liquid Chromatography (HPLC) pigment database was analyzed. It includes 2419 vertical pigment profiles, sampled in case 1 waters with various trophic states (0.03-6 mg Chla m-3). The relationships between [Chla]surf and the chlorophyll a vertical distribution, as previously derived by Morel and Berthon (1989), are fully confirmed. This agreement makes it possible to go further and to examine if similar relationships between [Chla]surf and the phytoplankton assemblage composition along the vertical can be derived. Thanks to the detailed pigment composition, and use of specific pigment biomarkers, the contribution to the local chlorophyll a concentration of three phytoplankton groups can be assessed. With some cautions, these groups coincide with three size classes, i.e., microplankton, nanoplankton and picoplankton. Corroborating previous regional findings (e.g., large species dominate in eutrophic environments, whereas tiny phytoplankton prevail in oligotrophic zones), the present results lead to an empirical parameterization applicable to most oceanic waters. The predictive skill of this parameterization is satisfactorily tested on a separate data set. With such a tool, the vertical chlorophyll a profiles of each group can be inferred solely from the knowledge of [Chla]surf. By combining this tool with satellite ocean color data, it becomes possible to quantify on a global scale the phytoplankton biomass associated with each of the three algal assemblages.

Annual cycles of deep-ocean biogeochemical export fluxes in subtropical and subantarctic waters, southwest Pacific Ocean

NASA Astrophysics Data System (ADS)

Nodder, Scott D.; Chiswell, Stephen M.; Northcote, Lisa C.

2016-04-01

The annual cycles of particle fluxes derived from moored sediment trap data collected during 2000-2012 in subtropical (STW) and subantarctic waters (SAW) east of New Zealand are presented. These observations are the most comprehensive export flux time series from temperate Southern Hemisphere latitudes to date. With high levels of variability, fluxes in SAW were markedly lower than in STW, reflecting the picophytoplankton-dominated communities in the iron-limited, high nutrient-low chlorophyll SAW. Austral spring chlorophyll blooms in surface STW were near synchronous with elevated fluxes of bio-siliceous, carbonate, and organic carbon-rich materials to the deep ocean, probably facilitated by diatom and/or coccolithophorid sedimentation. Lithogenic fluxes were also high in STW, compared to SAW, reflecting proximity to the New Zealand landmass. In contrast, the highest biogenic fluxes in SAW occurred in spring when surface chlorophyll concentrations were low, while highest annual chlorophyll concentrations were in summer with no associated flux increase. We hypothesize that the high spring export in SAW results from subsurface chlorophyll accumulation that is not evident from remote-sensing satellites. This material was also rich in biogenic silica, perhaps related to the preferential export of diatoms and other silica-producing organisms, such as silicoflagellates and radiolarians. Organic carbon fluxes in STW are similar to that of other mesotrophic to oligotrophic waters (˜6-7 mg C m-2 d-1), whereas export from SAW is below the global average (˜3 mg C m-2 d-1). Regional differences in flux across the SW Pacific and Tasman region reflect variations in physical processes and ecosystem structure and function.

Annual Cycles of Deep-ocean, Biogeochemical Export Fluxes and Biological Pump Processes in Subtropical and Subantarctic Waters, Southwest Pacific Ocean

NASA Astrophysics Data System (ADS)

Nodder, S.; Chiswell, S.; Northcote, L.

2016-02-01

One of the key aspects of the global carbon cycle is the efficiency and spatio-temporal variability of the biological pump. In this paper, the annual cycles of particle fluxes, derived from moored sediment trap data collected from 2000-12 in subtropical (STW) and subantarctic waters (SAW), east of New Zealand, are presented. These observations are the most comprehensive export flux time-series from temperate Southern Hemisphere latitudes to date. With high levels of variability, fluxes in SAW were markedly lower than in STW, reflecting the picophytoplankton-dominated communities in the iron-limited, high nutrient-low chlorophyll SAW. Austral spring chlorophyll blooms in surface STW were near-synchronous with elevated fluxes of bio-siliceous, carbonate and organic carbon-rich materials to the deep ocean, probably facilitated by diatom sedimentation. Lithogenic fluxes were also high in STW, compared to SAW, reflecting proximity to the New Zealand landmass. In contrast, the highest biogenic fluxes in SAW occurred in spring when surface chlorophyll concentrations were low, while highest annual chlorophyll concentrations were in summer with no associated flux increase. We hypothesize that the high spring export in SAW occurs from subsurface chlorophyll accumulations that are not evident from remote-sensing satellites. This material was also rich in biogenic silica, perhaps related to the preferential export of diatoms and other silica-producing organisms, such as silicoflagellates and radiolarians. Particle fluxes in STW are similar to that of other mesotrophic to oligotrophic waters ( 6-7 mgC m-2 d-1), whereas export from SAW is below global averages ( 3 mgC m-2 d-1), and is characterized by carbonate-dominated and prominent bio-siliceous deposition.

From Surface Chlorophyll a to Phytoplankton Community Composition in Oceanic Waters

NASA Technical Reports Server (NTRS)

Uitz, Julia; Claustre, Herve; Morel, Andre; Hooker, Stanford B.

2004-01-01

The objective of the present study is to examine the potential of using the near-surface total chlorophyll a concentration (C(sub surf)), as it can be derived from ocean color observation, to infer the column-integrated and the vertical distribution of the phytoplanktonic biomass, both in a quantitative way and in a qualitative way (z.e., in terms of community structure). Within this context, a large HPLC (High Performance Liquid Chromatography) pigment database has been analyzed. It includes 2419 vertical pigment profiles, all sampled in Case-1 waters with various trophic states. The relationshps between C(sub surf) and the total chlorophyll alpha vertical distribution, as previously derived by Morel and Berthon, are fully confirmed, as the present results coincide with the previous ones. This agreement allows to go further, namely to examine the possibility of extracting relationships between C(sub surf) and the vertical composition of the algal assemblages. Thanks to the detailed pigment composition available from HPLC measurements, the contribution of three size classes (micro-, nano-, and pico-phytoplankton) to the local total chlorophyll a concentration can be assessed. Corroborating previous findings (e.g., large species dominate in eutrophc environments, whereas tiny phytoplankton prevail in oligotrophic zones), the results lead to a statistically based parameterization. The predictive skill of this parameterization is successfully tested on a separate data set. With such a tool, the vertical total chlorophyll a profiles associated with each size class can be inferred from the sole knowledge of C(sub surf). By combining this tool with satellite ocean color data, it becomes conceivable to quantify on a global scale the phytoplankton biomass associated with each of the three size classes.

Improved exploration of fishery resources through the integration of remotely sensed merged sea level anomaly, chlorophyll concentration, and sea surface temperature

NASA Astrophysics Data System (ADS)

Priya, R. Kanmani Shanmuga; Balaguru, B.; Ramakrishnan, S.

2013-10-01

The capabilities of evolving satellite remote sensing technology, combined with conventional data collection techniques, provide a powerful tool for efficient and cost effective management of living marine resources. Fishes are the valuable living marine resources producing food, profit and pleasure to the human community. Variations in oceanic condition play a role in natural fluctuations of fish stocks. The Satellite Altimeter derived Merged Sea Level Anomaly(MSLA) results in the better understanding of ocean variability and mesosclae oceanography and provides good possibility to reveal the zones of high dynamic activity. This study comprised the synergistic analysis of signatures of SEAWIFS derived chlorophyll concentration, National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer(NOAA-AVHRR) derived Sea Surface Temperature and the monthly Merged Sea Level Anomaly data derived from Topex/Poseidon, Jason-1 and ERS-1 Altimeters for the past 7 years during the period from 1998 to 2004. The overlapping Chlorophyll, SST and MSLA were suggested for delineating Potential Fishing Zones (PFZs). The Chlorophyll and SST data set were found to have influenced by short term persistence from days to week while MSLA signatures of respective features persisted for longer duration. Hence, the study used Altimeter derived MSLA as an index for long term variability detection of fish catches along with Chlorophyll and SST images and the maps showing PFZs of the study area were generated. The real time Fishing statistics of the same duration were procured from FSI Mumbai. The catch contours were generated with respect to peak spectra of chlorophyll variation and trough spectra of MSLA and SST variation. The vice- a- versa patterns were observed in the poor catch contours. The Catch Per Unit Effort (CPUE) for each fishing trail was calculated to normalize the fish catch. Based on the statistical analysis the actual CPUEs were classified at each probable MSLA depth zones and plotted on the same images.

Comparison of Methods to Determine Algal Concentrations in Freshwater Lakes

NASA Astrophysics Data System (ADS)

Georgian, S. E.; Halfman, J. D.

2008-12-01

Algal populations are extremely important to the ecological health of freshwater lake systems. As lakes become eutrophic (highly productive) through nutrient loading, sediment accumulation rates increase, bottom waters become anoxic in the mid-to late summer, the opacity of the water column decreases, and significantly decreases the lake's potential as a drinking water source and places respiratory stress on aquatic animals. One indicator of eutrophication is increasing algal concentrations over annual time frames. Algal concentrations can be measured by the concentration of chlorophyll a, or less directly by fluorescence, secchi disk depth, and turbidity by backscattering and total suspended solids. Here, we present a comparison of these methods using data collected on Honeoye, Canandaigua, Keuka, Seneca, Cayuga, Owasco, Skaneateles, and Otisco, the largest Finger Lakes of western and central New York State during the 2008 field season. A total of 124 samples were collected from at least two mid-lake, deep-water sites in each lake monthly through the 2008 field season (May-Oct); Seneca Lake was sampled weekly at four sites and Cayuga Lake every two weeks at six sites. Secchi depths, CTD profiles and surface water samples were collected at each site. Chlorophyll a was measured by spectrophotometer in the lab after filtration at 0.45 um and digestion of the residue in acetone. Water samples were also filtered through pre-weighed glass-fiber filters for total suspended solids concentrations. A SBE-25 SeaLogger CTD collected profiles of turbidity and fluorescence with WetLabs ECO FL-NTU. Surface CTD values were used in the comparison. The strongest linear correlations were detected between chlorophyll-a and fluorescence (r2 = 0.65), and total suspended solids and turbidity (r2 = 0.63). Weaker correlations were detected between secchi depths and chlorophyll-a (r2 = 0.42), and secchi depths and turbidity (r2 = 0.46). The weakest correlations were detected between secchi depths and fluorescence (r2 = 0.29), total suspended solids and fluorescence (r2 = 0.29), chlorophyll-a and turbidity (r2 = 0.34) and fluorescence and turbidity (r2 = 0.25). The results suggest that water clarity in these lakes was controlled by both inorganic and organic (algal) suspended matter, and each method typically focuses on either the organic or inorganic fractions of the total suspended sediment population. Interestingly, fluorescence profiles revealed algal peaks at depth in the epilimnion and occasionally in the upper hypolimnion of these lakes. The peak in fluorescence was shallower in algal-rich lakes. Thus, lake monitoring protocols and assessments should include all of these parameters to adequately quantify the type and concentration of suspended matter, and expand from surface samples to integrate the entire water column.

Biogeography of photosynthetic light-harvesting genes in marine phytoplankton.

PubMed

Bibby, Thomas S; Zhang, Yinan; Chen, Min

2009-01-01

Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound protein complexes or phycobilin-bound protein complexes, respectively. Here, we use the Global Ocean Sampling (GOS) Project as a unique and powerful tool to analyze the environmental diversity of photosynthetic light-harvesting genes in relation to available metadata including geographical location and physical and chemical environmental parameters. All light-harvesting gene fragments and their metadata were obtained from the GOS database, aligned using ClustalX and classified phylogenetically. Each sequence has a name indicative of its geographic location; subsequent biogeographical analysis was performed by correlating light-harvesting gene budgets for each GOS station with surface chlorophyll concentration. Using the GOS data, we have mapped the biogeography of light-harvesting genes in marine cyanobacteria on ocean-basin scales and show that an environmental gradient exists in which chlorophyll concentration is correlated to diversity of light-harvesting systems. Three functionally distinct types of light-harvesting genes are defined: (1) the phycobilisome (PBS) genes of Synechococcus; (2) the pcb genes of Prochlorococcus; and (3) the iron-stress-induced (isiA) genes present in some marine Synechococcus. At low chlorophyll concentrations, where nutrients are limited, the Pcb-type light-harvesting system shows greater genetic diversity; whereas at high chlorophyll concentrations, where nutrients are abundant, the PBS-type light-harvesting system shows higher genetic diversity. We interpret this as an environmental selection of specific photosynthetic strategy. Importantly, the unique light-harvesting system isiA is found in the iron-limited, high-nutrient low-chlorophyll region of the equatorial Pacific. This observation demonstrates the ecological importance of isiA genes in enabling marine Synechococcus to acclimate to iron limitation and suggests that the presence of this gene can be a natural biomarker for iron limitation in oceanic environments.

Quality of surface-water supplies in the Triangle area of North Carolina, water year 2008

USGS Publications Warehouse

Giorgino, M.J.; Rasmussen, R.B.; Pfeifle, C.A.

2012-01-01

•Five lakes had chlorophyll a concentrations in excess of 40 micrograms per liter at least once during 2008, including Little River Reservoir, Falls Lake, Lake Benson, University Lake, and Jordan Lake.

Simulating Carbon Flux Dynamics with the Product of PAR Absorbed by Chlorophyll (fAPARchl)

NASA Astrophysics Data System (ADS)

Yao, T.; Zhang, Q.

2016-12-01

A common way to estimate the gross primary production (GPP) is to use the fraction of photosynthetically radiation (PAR) absorbed by vegetation (FPAR). However, only the PAR absorbed by chlorophyll of the canopy, not the PAR absorbed by the foliage or by the entire canopy, is used for photosynthesis. MODIS fAPARchl product, which refers to the fraction of PAR absorbed by chlorophyll of the canopy, is derived from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance by using an advanced leaf-canopy-soil-water-snow coupled radiative transfer model PROSAIL4. PROSAIL4 can retrieve surface water cover fraction, snow cover fraction, and physiologically active canopy chemistry components (chlorophyll concentration and water content), fraction of photosynthetically active radiation (PAR) absorbed by a canopy (fAPARcanopy), fraction of PAR absorbed by photosynthetic vegetation (PV) component (mainly chlorophyll) throughout the canopy (fAPARPV, i.e., fAPARchl) and fraction of PAR absorbed by non-photosynthetic vegetation (NPV) component of the canopy (fAPARNPV). We have successfully retrieved these vegetation parameters for selected areas with PROSAIL4 and the MODIS images, or simulated spectrally MODIS-like images. In this study, the product of PAR absorbed by chlorophyll (fAPARchl) has been used to simulate carbon flux over different kinds of vegetation types. The results show that MODIS fAPARchl product has the ability to better characterize phenology than current phenology model in the Community Land Model and it also will likely be able to increase the accuracy of carbon fluxes simulations.

Evaluating the portability of satellite derived chlorophyll-a algorithms for temperate inland lakes using airborne hyperspectral imagery and dense surface observations.

PubMed

Johansen, Richard; Beck, Richard; Nowosad, Jakub; Nietch, Christopher; Xu, Min; Shu, Song; Yang, Bo; Liu, Hongxing; Emery, Erich; Reif, Molly; Harwood, Joseph; Young, Jade; Macke, Dana; Martin, Mark; Stillings, Garrett; Stumpf, Richard; Su, Haibin

2018-06-01

This study evaluated the performances of twenty-nine algorithms that use satellite-based spectral imager data to derive estimates of chlorophyll-a concentrations that, in turn, can be used as an indicator of the general status of algal cell densities and the potential for a harmful algal bloom (HAB). The performance assessment was based on making relative comparisons between two temperate inland lakes: Harsha Lake (7.99 km 2 ) in Southwest Ohio and Taylorsville Lake (11.88 km 2 ) in central Kentucky. Of interest was identifying algorithm-imager combinations that had high correlation with coincident chlorophyll-a surface observations for both lakes, as this suggests portability for regional HAB monitoring. The spectral data utilized to estimate surface water chlorophyll-a concentrations were derived from the airborne Compact Airborne Spectral Imager (CASI) 1500 hyperspectral imager, that was then used to derive synthetic versions of currently operational satellite-based imagers using spatial resampling and spectral binning. The synthetic data mimics the configurations of spectral imagers on current satellites in earth's orbit including, WorldView-2/3, Sentinel-2, Landsat-8, Moderate-resolution Imaging Spectroradiometer (MODIS), and Medium Resolution Imaging Spectrometer (MERIS). High correlations were found between the direct measurement and the imagery-estimated chlorophyll-a concentrations at both lakes. The results determined that eleven out of the twenty-nine algorithms were considered portable, with r 2 values greater than 0.5 for both lakes. Even though the two lakes are different in terms of background water quality, size and shape, with Taylorsville being generally less impaired, larger, but much narrower throughout, the results support the portability of utilizing a suite of certain algorithms across multiple sensors to detect potential algal blooms through the use of chlorophyll-a as a proxy. Furthermore, the strong performance of the Sentinel-2 algorithms is exceptionally promising, due to the recent launch of the second satellite in the constellation, which will provide higher temporal resolution for temperate inland water bodies. Additionally, scripts were written for the open-source statistical software R that automate much of the spectral data processing steps. This allows for the simultaneous consideration of numerous algorithms across multiple imagers over an expedited time frame for the near real-time monitoring required for detecting algal blooms and mitigating their adverse impacts. Copyright © 2018 Elsevier B.V. All rights reserved.

Ocean color modeling: Parameterization and interpretation

NASA Astrophysics Data System (ADS)

Feng, Hui

The ocean color as observed near the water surface is determined mainly by dissolved and particulate substances, known as "optically-active constituents," in the upper water column. The goal of ocean color modeling is to interpret an ocean color spectrum quantitatively to estimate the suite of optically-active constituents near the surface. In recent years, ocean color modeling efforts have been centering upon three major optically-active constituents: chlorophyll concentration, colored dissolved organic matter, and scattering particulates. Many challenges are still being faced in this arena. This thesis generally addresses and deals with some critical issues in ocean color modeling. In chapter one, an extensive literature survey on ocean color modeling is given. A general ocean color model is presented to identify critical candidate uncertainty sources in modeling the ocean color. The goal for this thesis study is then defined as well as some specific objectives. Finally, a general overview of the dissertation is portrayed, defining each of the follow-up chapters to target some relevant objectives. In chapter two, a general approach is presented to quantify constituent concentration retrieval errors induced by uncertainties in inherent optical property (IOP) submodels of a semi-analytical forward model. Chlorophyll concentrations are retrieved by inverting a forward model with nonlinear IOPs. The study demonstrates how uncertainties in individual IOP submodels influence the accuracy of the chlorophyll concentration retrieval at different chlorophyll concentration levels. The important finding for this study shows that precise knowledge of spectral shapes of IOP submodels is critical for accurate chlorophyll retrieval, suggesting an improvement in retrieval accuracy requires precise spectral IOP measurements. In chapter three, three distinct inversion techniques, namely, nonlinear optimization (NLO), principal component analysis (PCA) and artificial neural network (ANN) are compared to assess their inversion performances to retrieve optically-active constituents for a complex nonlinear bio-optical system simulated by a semi-analytical ocean color model. A well-designed simulation scheme was implemented to simulate waters of different bio-optical complexity, and then the three inversion methods were applied to these simulated datasets for performance evaluation. In chapter four, an approach is presented for optimally parameterizing an irradiance reflectance model on the basis of a bio-optical dataset made at 45 stations in the Tokyo Bay and nearby regions between 1982 and 1984. (Abstract shortened by UMI.)

Light Absorption in Arctic Sea Ice - Black Carbon vs Chlorophyll

NASA Astrophysics Data System (ADS)

Ogunro, O. O.; Wingenter, O. W.; Elliott, S.; Hunke, E. C.; Flanner, M.; Wang, H.; Dubey, M. K.; Jeffery, N.

2015-12-01

The fingerprint of climate change is more obvious in the Arctic than any other place on Earth. This is not only because the surface temperature there has increased at twice the rate of global mean temperature but also because Arctic sea ice extent has reached a record low of 49% reduction relative to the 1979-2000 climatology. Radiation absorption through black carbon (BC) deposited on Arctic snow and sea ice surface is one of the major hypothesized contributors to the decline. However, we note that chlorophyll-a absorption owing to increasing biology activity in this region could be a major competitor during boreal spring. Modeling of sea-ice physical and biological processes together with experiments and field observations promise rapid progress in the quality of Arctic ice predictions. Here we develop a dynamic ice system module to investigate discrete absorption of both BC and chlorophyll in the Arctic, using BC deposition fields from version 5 of Community Atmosphere Model (CAM5) and vertically distributed layers of chlorophyll concentrations from Sea Ice Model (CICE). To this point, our black carbon mixing ratios compare well with available in situ data. Both results are in the same order of magnitude. Estimates from our calculations show that sea ice and snow around the Canadian Arctic Archipelago and Baffin Bay has the least black carbon absorption while values at the ice-ocean perimeter in the region of the Barents Sea peak significantly. With regard to pigment concentrations, high amounts of chlorophyll are produced in Arctic sea ice by the bottom microbial community, and also within the columnar pack wherever substantial biological activity takes place in the presence of moderate light. We show that the percentage of photons absorbed by chlorophyll in the spring is comparable to the amount attributed to BC, especially in areas where the total deposition rates are decreasing with time on interannual timescale. We expect a continuous increase in chlorophyll absorption as the biological activity becomes stronger in thin ice toward the center of the Arctic basin. Alternatively, a shift in relative importance could occur as total BC mixing ratios are reduced because of environmental advocacy.

Revisiting chlorophyll extraction methods in biological soil crusts - methodology for determination of chlorophyll a and chlorophyll a + b as compared to previous methods

NASA Astrophysics Data System (ADS)

Caesar, Jennifer; Tamm, Alexandra; Ruckteschler, Nina; Lena Leifke, Anna; Weber, Bettina

2018-03-01

Chlorophyll concentrations of biological soil crust (biocrust) samples are commonly determined to quantify the relevance of photosynthetically active organisms within these surface soil communities. Whereas chlorophyll extraction methods for freshwater algae and leaf tissues of vascular plants are well established, there is still some uncertainty regarding the optimal extraction method for biocrusts, where organism composition is highly variable and samples comprise major amounts of soil. In this study we analyzed the efficiency of two different chlorophyll extraction solvents, the effect of grinding the soil samples prior to the extraction procedure, and the impact of shaking as an intermediate step during extraction. The analyses were conducted on four different types of biocrusts. Our results show that for all biocrust types chlorophyll contents obtained with ethanol were significantly lower than those obtained using dimethyl sulfoxide (DMSO) as a solvent. Grinding of biocrust samples prior to analysis caused a highly significant decrease in chlorophyll content for green algal lichen- and cyanolichen-dominated biocrusts, and a tendency towards lower values for moss- and algae-dominated biocrusts. Shaking of the samples after each extraction step had a significant positive effect on the chlorophyll content of green algal lichen- and cyanolichen-dominated biocrusts. Based on our results we confirm a DMSO-based chlorophyll extraction method without grinding pretreatment and suggest the addition of an intermediate shaking step for complete chlorophyll extraction (see Supplement S6 for detailed manual). Determination of a universal chlorophyll extraction method for biocrusts is essential for the inter-comparability of publications conducted across all continents.

OCTS And Seawifs Bio-Optical Algorithm and Product Vaildattion and Intercomparison in US Coastal Waters

NASA Technical Reports Server (NTRS)

Brow, Chirstopher; Subramaniam, Ajit; Culver, Mary; Brock, John C.

2000-01-01

Monitoring the health of U.S. coastal waters is an important goal of the National Oceanic and Atmospheric Administration (NOAA). Satellite sensors are capable of providing daily synoptic data of large expanses of the U.S. coast. Ocean color sensor, in particular, can be used to monitor the water quality of coastal waters on an operational basis. To appraise the validity of satellite-derived measurements, such as chlorophyll concentration, the bio-optical algorithms used to derive them must be evaluated in coastal environments. Towards this purpose, over 21 cruises in diverse U.S. coastal waters have been conducted. Of these 21 cruises, 12 have been performed in conjunction with and under the auspices of the NASA/SIMBIOS Project. The primary goal of these cruises has been to obtain in-situ measurements of downwelling irradiance, upwelling radiance, and chlorophyll concentrations in order to evaluate bio-optical algorithms that estimate chlorophyll concentration. In this Technical Memorandum, we evaluate the ability of five bio-optical algorithms, including the current SeaWiFS algorithm, to estimate chlorophyll concentration in surface waters of the South Atlantic Bight (SAB). The SAB consists of a variety of environments including coastal and continental shelf regimes, Gulf Stream waters, and the Sargasso Sea. The biological and optical characteristics of the region is complicated by temporal and spatial variability in phytoplankton composition, primary productivity, and the concentrations of colored dissolved organic matter (CDOM) and suspended sediment. As such, the SAB is an ideal location to test the robustness of algorithms for coastal use.

The effects of temporal variability of mixed layer depth on primary productivity around Bermuda

NASA Technical Reports Server (NTRS)

Bissett, W. Paul; Meyers, Mark B.; Walsh, John J.; Mueller-Karger, Frank E.

1994-01-01

Temporal variations in primary production and surface chlorophyll concentrations, as measured by ship and satellite around Bermuda, were simulated with a numerical model. In the upper 450 m of the water column, population dynamics of a size-fractionated phytoplankton community were forced by daily changes of wind, light, grazing stress, and nutrient availability. The temporal variations of production and chlorophyll were driven by changes in nutrient introduction to the euphotic zone due to both high- and low-frequency changes of the mixed layer depth within 32 deg-34 deg N, 62 deg-64 deg W between 1979 and 1984. Results from the model derived from high-frequency (case 1) changes in the mixed layer depth showed variations in primary production and peak chlorophyll concentrations when compared with results from the model derived from low-frequency (case 2) mixed layer depth changes. Incorporation of size-fractionated plankton state variables in the model led to greater seasonal resolution of measured primary production and vertical chlorophyll profiles. The findings of this study highlight the possible inadequacy of estimating primary production in the sea from data of low-frequency temporal resolution and oversimplified biological simulations.

Simultaneous Measurements of Chlorophyll Concentration by Lidar, Fluorometry, above-Water Radiometry, and Ocean Color MODIS Images in the Southwestern Atlantic.

PubMed

Kampel, Milton; Lorenzzetti, João A; Bentz, Cristina M; Nunes, Raul A; Paranhos, Rodolfo; Rudorff, Frederico M; Politano, Alexandre T

2009-01-01

Comparisons between in situ measurements of surface chlorophyll-a concentration (CHL) and ocean color remote sensing estimates were conducted during an oceanographic cruise on the Brazilian Southeastern continental shelf and slope, Southwestern South Atlantic. In situ values were based on fluorometry, above-water radiometry and lidar fluorosensor. Three empirical algorithms were used to estimate CHL from radiometric measurements: Ocean Chlorophyll 3 bands (OC3M(RAD)), Ocean Chlorophyll 4 bands (OC4v4(RAD)), and Ocean Chlorophyll 2 bands (OC2v4(RAD)). The satellite estimates of CHL were derived from data collected by the MODerate-resolution Imaging Spectroradiometer (MODIS) with a nominal 1.1 km resolution at nadir. Three algorithms were used to estimate chlorophyll concentrations from MODIS data: one empirical - OC3M(SAT), and two semi-analytical - Garver, Siegel, Maritorena version 01 (GSM01(SAT)), and Carder(SAT). In the present work, MODIS, lidar and in situ above-water radiometry and fluorometry are briefly described and the estimated values of chlorophyll retrieved by these techniques are compared. The chlorophyll concentration in the study area was in the range 0.01 to 0.2 mg/m(3). In general, the empirical algorithms applied to the in situ radiometric and satellite data showed a tendency to overestimate CHL with a mean difference between estimated and measured values of as much as 0.17 mg/m(3) (OC2v4(RAD)). The semi-analytical GSM01 algorithm applied to MODIS data performed better (rmse 0.28, rmse-L 0.08, mean diff. -0.01 mg/m(3)) than the Carder and the empirical OC3M algorithms (rmse 1.14 and 0.36, rmse-L 0.34 and 0.11, mean diff. 0.17 and 0.02 mg/m(3), respectively). We find that rmsd values between MODIS relative to the in situ radiometric measurements are < 26%, i.e., there is a trend towards overestimation of R(RS) by MODIS for the stations considered in this work. Other authors have already reported over and under estimation of MODIS remotely sensed reflectance due to several errors in the bio-optical algorithm performance, in the satellite sensor calibration, and in the atmospheric-correction algorithm.

Spatial and temporal variability of phytoplankton chlorophyll and carbon in the equatorial Pacific, 2005 to 2008: Observations from ships and satellites.

NASA Astrophysics Data System (ADS)

Craig, J. D.; Strutton, P. G.; Evans, W.

2008-12-01

A database of chlorophyll fluorescence, particulate backscatter and beam attenuation was constructed from 17 cruises spanning the equatorial Pacific between August 2005 and February 2008. These optical measurements serve at least two important purposes. First, they can be used to document changes in phytoplankton abundance and physiology in a globally significant ecosystem. Second, they represent an important validation database for satellite observations that form the core of emerging primary productivity models. The data consist of CTD profiles from the surface to 1000m at least every degree of latitude between 8N and 8S, from near the Galapagos to beyond the date line. The optical data were calibrated with in situ samples of chlorophyll and particulate organic carbon (POC) from 4 of the 17 cruises. Chlorophyll concentration was derived from a multiple linear regression of chlorophyll fluorescence, time of day and depth, to account for photoinhibition of the fluorescence signal near the surface during the day. POC was derived from both particulate backscatter and beam attenuation. The optical data were then used to produce maps and latitude-depth sections of chlorophyll and POC for cruises where no in situ samples exist. In the eastern and central equatorial Pacific, phytoplankton chlorophyll to carbon ratios decreased by 30 to 50 percent during the weak El Nino conditions of 2006-2007. This change was due mostly to a decrease in chlorophyll, while POC remained relatively constant. In the western Pacific, the decrease in chl:C was absent, but an increase occurred in early 2008 when the system recovered from El Nino. Changes in chl:C, mostly indicative of photoadaptation, were also observed with depth and latitude as upwelled waters from the equator move poleward. Satellite-based maps of chlorophyll, phytoplankton C and chl:C were also produced and compared with the in situ optical measurements, with mostly good agreement.

Oceanic turbidity and chlorophyll as inferred from ERTS-1 observations

NASA Technical Reports Server (NTRS)

Curran, R. J.

1973-01-01

Spectral signatures of phytoplankton and other obscuring effects are considered in order to determine how to best use satellite data. The results of this study were then used to analyze the spectral data obtained from the ERTS-1 multispectral scanner (MSS). The analyzed satellite data were finally compared with surface ship measurements of chlorophyll concentration. It was found that the effects of water turbidity on the multispectral imagery can be discriminated by rationing the two shortest wavelength channels so that the effect of phytoplankton is enhanced.

Influence of microorganism content in suspended particles on the particle-water partitioning of mercury in semi-enclosed coastal waters.

PubMed

Jang, Jiyi; Kim, Hyunji; Han, Seunghee

2014-02-01

It is known that particle scavenging of mercury (Hg) can be affected by the abundance of particulate organic matter in coastal waters. However, the role of living organic particles in Hg scavenging is not yet completely understood. In this study, we hypothesized that an abundance of living organic particles (i.e., phytoplankton and bacteria) would influence the particle-water partitioning of Hg in coastal waters. Surface seawater samples were collected from eight stations in Gwangyang Bay, Korea, in three seasons (November 2009, April 2010, and October 2010) for the determination of concentrations of suspended particulate matter (including chlorophyll-a and bacteria), and Hg in unfiltered and filtered waters. We found that more Hg partitioned toward particulate matter when phytoplankton biomass, indicated from the chlorophyll-a concentration in a particle, was higher. In the low algal season, when [chlorophyll-a]<0.6 μg L(-1), the bacterial number, instead of chlorophyll-a concentration in particle, showed a positive correlation with the particle-water partition coefficient of Hg. Overall, microbial abundance seems to play a critical role in particle scavenging of Hg in coastal water. Taking this result in light of Hg in pristine coastal zones, we predict that increases in algal biomass amplify the potential for algae to transfer Hg to marine food chains. © 2013.

Contribution of Co2+ in increasing chlorophyll a concentration of Nannochloropsis salina in controlled Conwy medium

NASA Astrophysics Data System (ADS)

Hala, Y.; Taba, P.; Suryati, E.; Kasih, P.; Firman, N. F.

2018-03-01

A research in determining the contribution of Co2+ on the increase of chlorophyll a concentration of Nannochloropsis salina has been caried out. The cultivation of N. salina was conducted in the Conwy medium with a salinity of 5%o and 25%o and various Co2+ concentration (2, 4, and 8 ppm). In this research, Co2+ was exposed early in the cultivation of N. salina. The growth of N. salina was observed daily by counting the number of populations using a haemocytometer while the chlorophyll a concentration was determined by a Uv-Vis spectrophotometer. The results showed that the growth of N. salina in the control was higher than that in the medium containing Co2+. The optimum growth time was achieved on 15th days (5%) and 8th days (25%). In the cultivation medium with a salinity of 5%, Co2+ with a concentration of 2 ppm increased the chlorophyll a level while Co2+ with concentrations of 4 and 8 ppm decreased it. In the medium of cultivation with a salinity of 25%, the increase in chlorophyll a level was observed at Co2+ concentrations of 2 and 4 ppm whereas the decrease in chlorophyl a level was given at a concentration of 8 ppm. It can be concluded that at low concentrations, Co2+ increased the concentration of chlorophyll a in N. salina.

LANDSAT menhaden and thread herring resources investigation. [Gulf of Mexico

NASA Technical Reports Server (NTRS)

Kemmerer, A. J. (Principal Investigator); Brucks, J. T.; Butler, J. A.; Faller, K. H.; Holley, H. J.; Leming, T. D.; Savastano, K. J.; Vanselous, T. M.

1977-01-01

The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques.

Influence of Typhoon Matsa on Phytoplankton Chlorophyll-a off East China

PubMed Central

Shao, Jinchao; Han, Guoqi; Yang, Dezhou

2015-01-01

Typhoons can cause strong disturbance, mixing, and upwelling in the upper layer of the oceans. Rich nutrients from the subsurface layer can be brought to the euphotic layer, which will induce the phytoplankton to breed and grow rapidly. In this paper, we investigate the impact of an intense and fast moving tropical storm, Typhoon Matsa, on phytoplankton chlorophyll-a (Chl-a) concentration off East China. By using satellite remote sensing data, we analyze the changes of Chl-a concentration, Sea Surface Temperature (SST) and wind speed in the pre- and post-typhoon periods. We also give a preliminary discussion on the different responses of the Chl-a concentration between nearshore and offshore waters. In nearshore/coastal regions where nutrients are generally rich, the Chl-a maximum occurs usually at the surface or at the layer close to the surface. And, in offshore tropical oligotrophic oceans, the subsurface maxima of Chl-a exist usually in the stratified water column. In an offshore area east of Taiwan, the Chl-a concentration rose gradually in about two weeks after the typhoon. However, in a coastal area north of Taiwan high Chl-a concentration decreased sharply before landfall, rebounded quickly to some degree after landfall, and restored gradually to the pre-typhoon level in about two weeks. The Chl-a concentration presented a negative correlation with the wind speed in the nearshore area during the typhoon, which is opposite to the response in the offshore waters. The phenomena may be attributable to onshore advection of low Chl-a water, coastal downwelling and intensified mixing, which together bring pre-typhoon surface Chl-a downward in the coastal area. In the offshore area, the typhoon may trigger increase of Chl-a concentration through uptake of nutrients by typhoon-induced upwelling and entrainment mixing. PMID:26407324

A review of ocean chlorophyll algorithms and primary production models

NASA Astrophysics Data System (ADS)

Li, Jingwen; Zhou, Song; Lv, Nan

2015-12-01

This paper mainly introduces the five ocean chlorophyll concentration inversion algorithm and 3 main models for computing ocean primary production based on ocean chlorophyll concentration. Through the comparison of five ocean chlorophyll inversion algorithm, sums up the advantages and disadvantages of these algorithm,and briefly analyzes the trend of ocean primary production model.

Impacts of mesoscale eddies on biogeochemical cycles in the South China Sea

NASA Astrophysics Data System (ADS)

Xiu, P.; Chai, F.; Guo, M.

2016-02-01

Biogeochemical cycles associated with mesoscale eddies in the South China Sea (SCS) are investigated by using satellite surface chlorophyll concentration, altimeter data, satellite sea surface temperature, and a coupled physical-biogeochemical Pacific Ocean model (ROMS-CoSiNE) simulation for the period from 1991 to 2007. Considering the annual mean, composite analysis reveals that cyclonic eddies are associated with higher concentrations of nutrients, phytoplankton and zooplankton while the anticyclonic eddies are with lower concentrations compared with surrounding waters, which is generally controlled by the eddy pumping mechanism. Dipole structures of vertical fluxes with net upward motion in cyclonic eddies and net downward motion in anticyclonic eddies are also revealed. During the lifetime of an eddy, the evolutions of physical, biological, and chemical structures are not linearly coupled at the eddy core where plankton grow and composition of the community depend not only on the physical and chemical processes but also on the adjustments by the predator-prey relationship. Considering the seasonal variability, we find eddy pumping mechanisms are generally dominant in winter and eddy advection effects are dominant in summer. Over the space, variability of chlorophyll to the west of Luzon Strait and off northwest of Luzon Island are mainly controlled by eddy pumping mechanism. In regions off the Vietnam coast, chlorophyll distributions are generally associated with horizontal eddy advection. This research highlights different mesoscale mechanisms affecting biological structures that can potentially disturb ocean biogeochemical cycling processes in the South China Sea.

Inherent limitations of nondestructive chlorophyll meters: a comparison of two types of meters

NASA Technical Reports Server (NTRS)

Monje, O. A.; Bugbee, B.

1992-01-01

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-wavelengh, 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.

Instability of chlorophyll in yellow lupin seedlings grown in soil contaminated with ciprofloxacin and tetracycline.

PubMed

Rydzyński, Dariusz; Piotrowicz-Cieślak, Agnieszka I; Grajek, Hanna; Michalczyk, Dariusz J

2017-10-01

With increasing soil concentrations of ciprofloxacin and tetracycline a decrease of leaf chlorophyll content was observed. Tetracycline was more detrimental than ciprofloxacin. The chlorophyll content in plants growing for ten days on a tetracycline containing soil decreased by 68%. The decrease of chlorophyll concentration was even sharper in new leaves that formed after application of the antibiotic (up to 81% drop). The comparison of absorption spectra of commercial, reagent grade chlorophyll, alone and incubated with antibiotics, has shown that ciprofloxacin and tetracycline can react directly with chlorophyll and decrease its concentration by 47.7% and 48.5%, respectively. The changes in fluorescence spectra confirmed the formation of chlorophyll degradation product. The chlorophyll decay was a second order reaction and depended on antibiotic concentration and duration of exposure. Reaction rate constants differed with antibiotics and their soil concentrations. With increasing contents of antibiotics in soil the constant of chlorophyll degradation rate in lupin plants increased from k = 870 M -1 day -1 for 3 mg ciprofloxacin to k = 2490 M -1 day -1 for 90 mg ciprofloxacin, and in the case of tetracycline the reaction rate constant increased from k = 1330 M -1 day -1 to k = 2910 M -1 day -1 . The sensitivity of chlorophyll to ciprofloxacin and tetracycline was confirmed by determining EC and TU indices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Long-term Trend of Satellite-observed Chlorophyll-a Concentration Variations in the East/Japan Sea

NASA Astrophysics Data System (ADS)

Park, J. E.; PARK, K. A.

2016-02-01

Long-term time-series of satellite ocean color data enable us to analyze the effects of climate change on ocean ecosystem through chlorophyll-a concentration as a proxy for phytoplankton biomass. In this study, we constructed a 17 year-long time-series dataset (1998-2014) of chlorophyll-a concentration by combining SeaWiFS (Obrview-2, 1997-2010) and MODIS (Aqua, 2002-present) data in the East Sea (Japan Sea). Several types of errors such as anonymously high values (a speckle error), stripe-like patterns, discrepancy originating from time gap between the two satellites were eliminated to enhance the accuracy of chlorophyll-a concentration data. The composited chlorophyll-a concentration maps, passing through the post-processing of the speckle errors, were improved significantly, by 14% of abnormal variability in maximum. Using the database, we investigated spatial and temporal variability of chlorophyll-a concentration in the East Sea. Spatial distribution of long-term trend of chlorophyll-a concentration indicated obvious distinction between northern and southern regions of the subpolar front. It revealed predominant seasonal variabilities as well as long-term changes in the timings of spring bloom. This study addresses the important role of local climate change on fast changing ecosystem of the East Sea as one of miniature oceans.

Comparison of Euphausia superba, Euphausia crystallorophias, Pleuragramma antarcticum and Environmental Distributions in the Western Ross Sea

NASA Astrophysics Data System (ADS)

Davis, L.; Hofmann, E. E.; Klinck, J. M., II; Dinniman, M.; Pinones, M. A.

2016-02-01

Distributions of Antarctic krill (Euphausia superba), crystal krill (Euphausia crystallorophias), and Antarctic silverfish (Pleuragramma antarcticum) were constructed using observations collected in the western Ross Sea from 1988-2004. Distributions of mixed layer depth (MLD), water temperature below 200 m (an indicator for Circumpolar Deep Water, CDW), and surface speed were obtained from a Ross Sea circulation model; surface chlorophyll and percent sea ice coverage were obtained from satellite observations. The species and environmental distributions were analyzed to determine patterns and correlations. Statistical analyses of the distributions show that the three species are concentrated in specific regions and that their habitats have limited overlap. Antarctic krill are concentrated along the shelf break near Cape Adare and are associated with temperatures >0.5°C and -2°C to -0.75°C, 19-32% sea ice coverage, and high surface flow speeds. Crystal krill are concentrated in Terra Nova Bay in areas with depths of 400-600 m, temperatures < -1.3°, 50% or more sea ice coverage, shallow MLDs (2-36 m), moderate concentrations of chlorophyll (0.44 μg m-3) and low surface speeds (0.08 m s-1). Similarly, Antarctic silverfish are concentrated in Terra Nova Bay and are also found over the continental shelf in areas with depths of 500 m and temperatures of -2°C to -1°C. Additional statistical analyses provide insights into the relative contribution of the different environmental features to producing the distributions of the three species.

Tidal and seasonal variations in the quantity and composition of seston in a North American, mid-Atlantic saltmarsh

NASA Astrophysics Data System (ADS)

Huang, S.-C.; Kreeger, D. A.; Newell, R. I. E.

2003-03-01

We determined the concentration of seston, particulate organic matter, and biological components (chlorophyll a, bacteria, and heterotrophic nanoflagellates) for <25 μm size fraction seston over five seasons in Canary Creek saltmarsh, Delaware Bay, USA. This material is the potential food resource for suspension-feeding ribbed mussels, Geukensia demissa, that inhabit the marsh intertidal zone. For eight tidal cycles each season we collected water six times at hourly intervals from mid-flood tide to mid-ebb tide. Although the concentration of seston did not vary seasonally, there were significant seasonal variations (analysis of variance, P<0.05) in seston components, with chlorophyll a concentration being highest in May and bacteria and heterotrophic nanoflagellates most abundant in August. Seston composition also varied within each tidal cycle with a magnitude as great as the seasonal variation. We conclude that ribbed mussels are subject to an unpredictable food supply that varies in composition and concentration on the order of hours and days. In contrast to the pronounced temporal changes, seston characteristics did not differ significantly among sampling locations within the marsh, or between samples collected close to the sediment surface and from the upper water column. Resuspension of sediment particles caused by tidal flow was not evident in tidal creeks and there were no dominant patterns in total seston concentration corresponding to tidal stages (flood tide, high slack water, and ebb tide) over the five sampling months. The abundance of biological components in the seston, including chlorophyll a, bacteria, and heterotrophic nanoflagellates, were significantly greater during high flood tide and high slack water than during ebb tide. The decline of biological components, particularly chlorophyll a in the ebb tide, indicates that this temperate saltmarsh imported organic material produced in the Delaware estuary.

OCTS and SeaWiFS Bio-Optical Algorithm and Product Validation and Intercomparison in US Coastal Waters. Chapter 5

NASA Technical Reports Server (NTRS)

Brown, Christopher W.; Subramaniam, Ajit; Culver, Mary; Brock, John C.

2001-01-01

Monitoring the health of US coastal waters is an important goal of the National Oceanic and Atmospheric Administration (NOAA). Satellite sensors are capable of providing daily synoptic data of large expanses of the US coast. Ocean color sensors, in particular, can be used to monitor the water quality of coastal waters on an operational basis. To appraise the validity of satellite-derived measurements, such as chlorophyll concentration, the bio-optical algorithms used to derive them must be evaluated in coastal environments. Towards this purpose, over 21 cruises in diverse US coastal waters have been conducted. Of these 21 cruises, 12 have been performed in conjunction with and under the auspices of the NASA/Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project. The primary goal of these cruises has been to obtain in-situ measurements of downwelling irradiance, upwelling radiance, and chlorophyll concentrations in order to evaluate bio-optical algorithms that estimate chlorophyll concentration. In this Technical Memorandum, we evaluate the ability of five bio-optical algorithms, including the current Sea-Viewing Wide Field-of-view Sensor (SeaWiFS) algorithm, to estimate chlorophyll concentration in surface waters of the South Atlantic Bight (SAB). The SAB consists of a variety of environments including coastal and continental shelf regimes, Gulf Stream waters, and the Sargasso Sea. The biological and optical characteristics of the region is complicated by temporal and spatial variability in phytoplankton composition, primary productivity, and the concentrations of colored dissolved organic matter (CDOM) and suspended sediment. As such, the SAB is an ideal location to test the robustness of algorithms for coastal use.

Wind driven nutrient and subsurface chlorophyll-a enhancement in the Bay of La Paz, Gulf of California

NASA Astrophysics Data System (ADS)

Coria-Monter, Erik; Monreal-Gómez, María Adela; Salas de León, David Alberto; Durán-Campos, Elizabeth; Merino-Ibarra, Martín

2017-09-01

Nutrient and chlorophyll-a distributions in the Bay of La Paz, Gulf of California, Mexico were analyzed during the late spring of 2004 to assess their relations to hydrography and circulation patterns. The results show the presence of both Gulf of California Water and Subtropical Subsurface Water. Water circulation was dominated by wind stress driven cyclonic circulation along f / H contours (f is planetary vorticity and H is depth), and upwelling resulting from the divergence shows a vertical velocity of ∼0.4 m d-1. Nutrient concentrations were higher in the center of the cyclonic pattern, where a rise in the nutricline contributed nutrients to the euphotic layer as a result of Ekman pumping. The vertical section showed the presence of a chlorophyll-a maximum at the thermocline shoaling to a depth of only 12 m. Along the surface, two peaks of chlorophyll-a were observed, one at Boca Grande and another off San Juan de la Costa, associated with upwelling and mixing derived from current interactions with abrupt topographies. The chlorophyll-a maximum increased from 0.8 mg m-3 in the external part of the cyclonic pattern to 2.0 mg m-3 in its center. The vertically integrated chlorophyll-a concentrations followed a similar pattern, rising from 10 to 20 mg m-2 and reaching their highest values in the center of the cyclonic circulation pattern. A schematic model was developed to describe processes that occur in late spring: the wind stress driven cyclonic structure promotes upward nutrient flux, which in turn drives an enhancement of chlorophyll-a. Upwelling was found to be the main mechanism of fertilization responsible for the enhancement of productivity levels by means of nutrient transport into the euphotic zone during spring. Other chlorophyll enhancement areas point to the occurrence of additional fertilization processes that may derive from interactions between cyclonic circulation patterns and the topography off of San Juan de la Costa, where phosphate mining occurs.

Aerobic methane production in surface waters of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Finke, N.; Crespo-Medina, M.; Schweers, J.; Joye, S. B.

2011-12-01

Near surface water of the global oceans often show elevated methane concentrations compared to the water column below with concentrations in supersaturation in regard to the atmosphere (Lamontagne et al. 1973), resulting in a source of this potent greenhouse gas to the atmosphere. The mechanisms leading to methane supersaturation in surface waters remains unclear. Incubations with Trichodesmium-containing Pacific surface water suggested methylphosphonate as potential methane precursor under phosphate limiting conditions (Karl et al. 2008), whereas in phosphate rich Arctic surface waters, DMSP addition stimulated methane production (Damm et al. 2010). Surface waters of the Gulf of Mexico typically exhibit a methane maximum that is conincident with the deep chlorophyll maximum, below the depths where Trichodesmium is abundant. Addition of methylphosphonate, dimethylsulfoniopropionate (DMSP) or methane thiol (MeSH), the proposed methane precursor in DMSP conversion to methane, to oxic sea water did not affect methane production within the chlorophyll maximum at most stations, whereas methyl phosphonate addition stimulated methane production in the surface water and proposed deep Trichodesmium horizon. Pre-filtration of the water through a 10 μm sieve, which eliminated Trichodesmium, or through a 1.2 μm filter, which eliminated additional cyanobacteria such as Synechococcus, did not reduce methane production. Under dark oxic and dark anoxic conditions, however, methane production was reduced 5 and 7-20 fold, respectively, indicating that anerobic methane production in anoxic microniches is not responsible for the methane production. The reduction of methane production under dark conditions suggests that methane production is, in some yet unrecognized way, linked to phototrophic metabolism. Cyanobacteria are likely not responsible for the observed aerobic methane production in the surface waters of the Gulf of Mexico and while methylphosphonate is a potential precursor in the surface waters, the precursor and methanism of methane production within the coincident deep chlorophyll/methane maximum remains unknown. Lamontagne R, Swinnert J, Linnenbo V, Smith WD (1973) Methane concentrations in various marine environments. Journal of Geophysical Research 78, 5317-5324 Karl DM et al. (2008) Aerobic production of methane in the sea. Nature Geosciences 1, 473-478 Damm E et al. (2010) Methane production in aerobic oligotrophic surface water in the central Arctic Ocean. Biogeosciences 7, 1099-1108

Arctic Ocean CO2 uptake: an improved multiyear estimate of the air-sea CO2 flux incorporating chlorophyll a concentrations

NASA Astrophysics Data System (ADS)

Yasunaka, Sayaka; Siswanto, Eko; Olsen, Are; Hoppema, Mario; Watanabe, Eiji; Fransson, Agneta; Chierici, Melissa; Murata, Akihiko; Lauvset, Siv K.; Wanninkhof, Rik; Takahashi, Taro; Kosugi, Naohiro; Omar, Abdirahman M.; van Heuven, Steven; Mathis, Jeremy T.

2018-03-01

We estimated monthly air-sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C yr-1. Seasonal to interannual variation in the CO2 influx was also calculated.

Spatio-temporal patterns of Ulva prolifera blooms and the corresponding influence on chlorophyll-a concentration in the Southern Yellow Sea, China.

PubMed

Sun, Xiao; Wu, Mengquan; Xing, Qianguo; Song, Xiaodong; Zhao, Deheng; Han, Qianqian; Zhang, Guangzong

2018-06-04

The world's largest macroalgal blooms (MABs) caused by the Ulva prolifera outbreaks have occurred every summer since 2007 in the Southern Yellow Sea, China. Accumulating evidence showed that MABs may deteriorate the regional marine environment and influence the growth of some primary producers such as phytoplankton. In this study, we investigated the spatio-temporal patterns of U. prolifera green tides and chlorophyll-a concentration in the Southern Yellow Sea in 2015 using satellite images obtained from HJ-1 CCD, MODIS, and GOCI. The correlation between the distributions of U. prolifera abundance and chlorophyll-a concentration was analyzed quantitatively by setting up a series of 5 × 5 km experimental grids, and we also discussed the possible mechanisms about the influence of U. prolifera blooms on the other floating microalgae. The results showed that the development of U. prolifera blooms in the Southern Yellow Sea in 2015 could be featured as "appearance - development - outbreak - decline - disappearance", while the concentration of chlorophyll-a showed "increase - sharp decline - slow recovery - stabilization" from April to August. We also found that the concentration of chlorophyll-a had the following relationships with U. prolifera temporally: (1) the concentration of chlorophyll-a increased with the growth of U. prolifera from April to mid-May; (2) the chlorophyll-a concentration decreased sharply with the dramatically increased coverage of U. prolifera in June; and (3) the chlorophyll-a concentration slowly recovered and finally stabilized as U. prolifera decreased in July. Generally, there was a negative correlation between the occurrence of U. prolifera and chlorophyll-a concentration in the Southern Yellow Sea, China. Our results showed that the outbreak of U. prolifera does have a certain impact on the growth and reproduction of planktonic microalgae, and it suggests that U. prolifera blooms have potentially altered the ecological balance in the coastal waters of the Southern Yellow Sea. Copyright © 2018. Published by Elsevier B.V.

The Validity Chlorophyll-a Estimation by Sun Induced Fluorescence in Estuarine Waters: An Analysis of Long-term (2003-2011) Water Quality Data from Tampa Bay, Florida (USA)

NASA Technical Reports Server (NTRS)

Moreno-Madrinan, Max Jacobo; Fischer, Andrew

2012-01-01

Satellite observation of phytoplankton concentration or chlorophyll-a is an important characteristic, critically integral to monitoring coastal water quality. However, the optical properties of estuarine and coastal waters are highly variable and complex and pose a great challenge for accurate analysis. Constituents such as suspended solids and dissolved organic matter and the overlapping and uncorrelated absorptions in the blue region of the spectrum renders the blue-green ratio algorithms for estimating chlorophyll-a inaccurate. Measurement of sun-induced chlorophyll fluorescence, on the other hand, which utilizes the near infrared portion of the electromagnetic spectrum, may provide a better estimate of phytoplankton concentrations. While modelling and laboratory studies have illustrated both the utility and limitations of satellite baseline algorithms based on the sun induced chlorophyll fluorescence signal, few have examined the empirical validity of these algorithms using a comprehensive long term in situ data set. In an unprecedented analysis of a long term (2003-2011) in situ monitoring data from Tampa Bay, Florida (USA), we assess the validity of the FLH product from the Moderate Resolution Imaging Spectrometer (MODIS) against chlorophyll ]a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions within the estuary including water depth, distance from shore and structures and eight water quality parameters. From the 39 station for which data was derived, 22 stations showed significant correlations when the FLH product was matched with in situ chlorophyll-alpha data. The correlations (r2) for individual stations within Tampa Bay ranged between 0.67 (n=28, pless than 0.01) and-0.457 (n=12, p=.016), indicating that for some areas within the Bay, FLH can be a good predictor of chlorophyll-alpha concentration and hence a useful tool for the analysis of water quality. Overall, the results show a 106% increase in the validity of chlorophyll -a concentration estimates using FLH over the standard the blue-green OC3M algorithm. This analysis also illustrates that the correlations between FLH and in situ chlorophyll -a measurements increases with increasing water depth and distance of the monitoring sites from both the shore and structures. However, due to confounding factors related to the complexity of the estuarine system, a linear improvement in the FLH to chlorophyll ]a relationship was not clearly noted with increasing depth and distance from shore alone. Correlations of FLH with turbidity, nutrients (total nitrogen and total phosphorous) biological oxygen demand, salinity, sea surface temperature correlated positively with FLH concentrations, while dissolved oxygen and pH showed negative correlations. Principle component analyses are employed to further describe the relationships between the multivariate water quality parameters and the FLH product. The majority of sites with higher and very significant correlations (pless than 0.01) also showed high correlation values for nutrients, turbidity and biological oxygen demand. These sites were on average in greater than seven meters of water and over five kilometers from shore. A thorough understanding of the relationship between the MODIS FLH product and in situ water quality parameters will enhance our understanding of the accuracy MODIS fs global FLH algorithm and assist in optimizing its calibration for use in monitoring the quality of estuarine and coastal waters worldwide.

Optimal Reflectance, Transmittance, and Absorptance Wavebands and Band Ratios for the Estimation of Leaf Chlorophyll Concentration

NASA Technical Reports Server (NTRS)

Carter, Gregory A.; Spiering, Bruce A.

2000-01-01

The present study utilized regression analysis to identify: wavebands and band ratios within the 400-850 nm range that could be used to estimate total chlorophyll concentration with minimal error; and simple regression models that were most effective in estimating chlorophyll concentrations were measured for two broadleaved species, a broadleaved vine, a needle-leaved conifer, and a representative of the grass family.Overall, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentration at wavelengths near 700 nm, although regressions were strong as well in the 550-625 nm range.

Effect of crude oil contamination on the chlorophyll content and morpho-anatomy of Cyperus brevifolius (Rottb.) Hassk.

PubMed

Baruah, Plabita; Saikia, Rashmi Rekha; Baruah, Partha Pratim; Deka, Suresh

2014-11-01

Chlorophyll plays a pivotal role in the plant physiology and its productivity. Cultivation of plants in crude oil contaminated soil has a great impact on the synthesis of chlorophyll pigment. Morpho-anatomy of the experimental plant also shows structural deformation in higher concentrations. Keeping this in mind, a laboratory investigation has been carried out to study the effect of crude oil on chlorophyll content and morpho-anatomy of Cyperus brevifolius plant. Fifteen-day-old seedling of the plant was planted in different concentrations of the crude oil mixed soil (i.e., 10,000, 20,000, 30,000, 40,000, and 50,000 ppm). A control setup was also maintained without adding crude oil. Results were recorded after 6 months of plantation. Investigation revealed that there is a great impact of crude oil contamination on chlorophyll content of the leaves of the experimental plant. It also showed that chlorophyll a, chlorophyll b, and total chlorophyll content of leaves grown in different concentrations of crude oil were found to be lower than those of the control plant. Further, results also demonstrated that chlorophyll content was lowest in the treatment that received maximum dose of crude oil. It also showed that chlorophyll content was decreased with increased concentration of crude oil. Results also demonstrated that there was a reduction in plant shoot and root biomass with the increase of crude oil concentration. Results also revealed that the shoot biomass is higher than root biomass. Morphology and anatomy of the experimental plant also show structural deformation in higher concentrations. Accumulation of crude oil on the cuticle of the transverse section of the leaves and shoot forms a thick dark layer. Estimation of the level of pollution in an environment due to oil spill is possible by the in-depth study of the harmful effects of oil on the morphology and anatomy and chlorophyll content of the plants grown in that particular environment.

The potential for improving remote primary productivity estimates through subsurface chlorophyll and irradiance measurement

NASA Astrophysics Data System (ADS)

Jacox, Michael G.; Edwards, Christopher A.; Kahru, Mati; Rudnick, Daniel L.; Kudela, Raphael M.

2015-02-01

A 26-year record of depth integrated primary productivity (PP) in the Southern California Current System (SCCS) is analyzed with the goal of improving satellite net primary productivity (PP) estimates. Modest improvements in PP model performance are achieved by tuning existing algorithms for the SCCS, particularly by parameterizing carbon fixation rate in the vertically generalized production model as a function of surface chlorophyll concentration and distance from shore. Much larger improvements are enabled by improving the accuracy of subsurface chlorophyll and light profiles. In a simple vertically resolved production model for the SCCS (VRPM-SC), substitution of in situ surface data for remote sensing estimates offers only marginal improvements in model r2 (from 0.54 to 0.56) and total log10 root mean squared difference (from 0.22 to 0.21), while inclusion of in situ chlorophyll and light profiles improves these metrics to 0.77 and 0.15, respectively. Autonomous underwater gliders, capable of measuring subsurface properties on long-term, long-range deployments, significantly improve PP model fidelity in the SCCS. We suggest their use (and that of other autonomous profilers such as Argo floats) in conjunction with satellites as a way forward for large-scale improvements in PP estimation.

Analysis of Remote Sensing Data Reveals the Correlation of Anomalies between Aerosol Optical Depth and Chlorophyll-a Concentrations in the Red Sea Area

NASA Astrophysics Data System (ADS)

Coria, J.; Bonilla, J., III; Li, W.; El-Askary, H. M.; Qurban, M.; Garay, M. J.; Kalashnikova, O. V.

2017-12-01

The Red Sea has one of the highest salinities and one of the most diverse ecosystems in the world. We wanted to investigate how chlorophyll-a contributes to this diverse ecosystem. From 2002 to 2015, we observed an increase in aerosol optical depth (AOD) levels which we believed contributed to an increase in chlorophyll-a concentration levels. Focusing on the Red Sea we used the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Terra and Aqua platforms in order to acquire the data necessary for our research. After gathering the monthly data for the chlorophyll-a concentration and AOD for this period we normalized the data in order to find correlations between the two parameters. We found that there was a continuous increase in AOD from 2002 to 2015. Inversely we found that there was an overall decrease in chlorophyll-a concentration during this same time period. However, there was a correlation between AOD anomalies and chlorophyll-a anomalies that did not follow the decreasing trend of chlorophyll-a. These findings exemplified a two-month lag between the AOD anomalies and chlorophyll-a concentration anomalies. This shows that the increase in AOD has a significant impact on the chlorophyll-a conentration anomalies which in turn contributes to the overall greenness of the Red Sea. This is significant because there are many cities surrounding the Red Sea that depend on this diverse ecosystem as a stable food source.

The blue-to-green reflectance ratio and lake water quality

NASA Technical Reports Server (NTRS)

Piech, K. R.; Schott, J. R.; Stewart, K. M.

1978-01-01

Correlations between the relative values of the blue and green reflectances of a lake and water quality indices, such as depth of photic zone, Secchi disk transparency, attenuation coefficient, and chlorophyll concentration, have been observed during an intensive satellite, aircraft, and surface vessel study of Lake Ontario and Conesus Lake. Determinations of blue and green reflectances from Skylab S190A color imagery are in excellent agreement with values obtained from small-scale color imagery from aircraft. Further, the accuracy of the satellite data appears within that required for extrapolation to the water quality indices. The study has also determined that changes in chlorophyll, lignin, and humic acid concentration can be discriminated by the behavior of the blue-to-green reflectance ratio and the reflectances of the green and red bands.

Genetic variation and control of chloroplast pigment concentrations in Picea rubens, Picea mariana and their hybrids. I. Ambient and elevated [CO2] environments.

PubMed

Major, John E; Barsi, Debby C; Mosseler, Alex; Campbell, Moira

2007-03-01

Traits related to light-energy processing have significant ecological implications for plant fitness. We studied the effects of elevated atmospheric CO(2) concentration ([CO(2)]) on chloroplast pigment traits of a red spruce (RS) (Picea rubens Sarg.)-black spruce (BS) (P. mariana (Mill.) B.S.P.) genetic complex in two experiments: (1) a comparative species' provenance experiment from across the near-northern part of the RS range; and (2) an intra- and interspecific controlled-cross experiment. Results from the provenance experiment showed that total chlorophyll (a + b) concentration was, on average, 15% higher in ambient [CO(2)] than in elevated [CO(2)] (P < 0.001). In ambient [CO(2)], BS populations averaged 11% higher total chlorophyll and carotenoid concentrations than RS populations (P < 0.001). There were significant species, CO(2), and species x CO(2) interaction effects, with chlorophyll concentration decreasing about 7 and 26% for BS and RS, respectively, in response to elevated [CO(2)]. Results from the controlled-cross experiment showed that families with a hybrid index of 25 (25% RS) had the highest total chlorophyll concentrations, and families with hybrid indices of 75 and 100 had among the lowest amounts. Initial analysis of the controlled-cross experiment supported a more additive model of inheritance; however, parental analysis showed a significant and predominant male effect for chlorophyll concentration. In ambient and elevated [CO(2)] environments, crosses with BS males had 10.6 and 17.6% higher total chlorophyll concentrations than crosses with hybrid and RS males, respectively. Our results show that chlorophyll concentration is under strong genetic control, and that these traits are positively correlated with productivity within and across species. A significant positive correlation between chlorophyll concentration and the ratio of total plant N to root dry mass was also found (r = 0.872). The almost fourfold decrease in chlorophyll concentration in RS suggests that it would be at a competitive disadvantage compared with BS in a high [CO(2)] environment.

Variation of subsurface chlorophyll maximum layer from the vertical profiler and in-situ observation in the eastern coastal region of Korea (the East/Japan Sea)

NASA Astrophysics Data System (ADS)

Son, Y. T.; Chang, K. I.; Nam, S.; Kang, D. J.

2016-02-01

Coastal monitoring buoy (called it as ESROB) has been continually operated to monitor meteorological (wind, air temperature, air pressure, PAR) and oceanic properties (temperature, salinity, current, chlorophyll fluorescence, DO, turbidity) using equipment such as CTD, fluorometer and WQM (Water Quality Monitor) in the eastern coastal region of Korea (the East/Japan Sea) since April 2011. The ESROB produced temporal evolution of physical and biogeochemical parameters of the water column with high resolution of 10 min interval. In order to understand horizontal influence of physical and biogeochemical parameters on variation of subsurface chlorophyll maximum layer (SCM), interdisciplinary in-situ surveys with small R/V in the study area for about week were conducted in June/October 2014 and in May 2015. A wirewalker, a wave-driven vertically profiling platform (Rainville and Pinkel 2001), was also deployed at two points (about 30 m and 80 m water depth) along cross-shore direction with the ESROB for about one or two weeks with in-situ survey durations. The wirewalker was equipped with CTD, turbidity and chlorophyll a fluorometer profiler, which was completed approximately every 3 10 minute depending on sea surface state. The SCM was observed in almost every deployment nearest coast, except for June in 2014, with variation of semi- and diurnal time periods. Temporal evolution of the wirewalker showed that disappearance and reoccurrence of the SCM within the water column in October 2014, which was associated with vertical mixing induced by strong wind stress. Low salinity plume in the surface layer and shoaling of bottom cold water were concurrently observed after homogeneous water column, affecting another condition to the vertical distribution of chlorophyll a in this coastal region. Moreover in-situ observation with densely points and temporal interval for 1 day revealed that distribution with high concentration of chlorophyll a on isopycnal was association with the horizontal local circulation that has influence on stability (vertical stratification and shear) of the water column. Optical and biogeochemical parameter analyzed from the water samples, affecting on the variation of chlorophyll a concentration within the water column, will be also discussed in the presentation of Ocean Science Meeting.

Relations of biological indicators to nutrient data for lakes and streams in Pennsylvania and West Virginia, 1990-98

USGS Publications Warehouse

Brightbill, Robin A.; Koerkle, Edward H.

2003-01-01

The Clean Water Action Plan of 1998 provides a blueprint for federal agencies to work with states, tribes, and other stakeholders to protect and restore the Nation's water resources. The plan includes an initiative that addresses the nutrient-enrichment problem of lakes and streams across the United States. The U.S. Environmental Protection Agency (USEPA) is working to set nutrient criteria by nationwide nutrient ecoregions that are an aggregation of the Omernik level III ecoregions. Because low levels of nutrients are necessary for healthy streams and elevated concentrations can cause algal blooms that deplete available oxygen and kill off aquatic organisms, criteria levels are to be set, in part, using the relation between chlorophyll a and concentrations of total nitrogen and total phosphorus.Data from Pennsylvania and West Virginia, collected between 1990 and 1998, were analyzed for relations between chlorophyll a, nutrients, and other explanatory variables. Both phytoplankton and periphyton chlorophyll a concentrations from lakes and streams were analyzed separately within each of the USEPA nutrient ecoregions located within the boundaries of the two states. These four nutrient ecoregions are VII (Mostly Glaciated Dairy), VIII (Nutrient Poor, Largely Glaciated Upper Midwest and Northeast), IX (Southeastern Temperate Forested Plains and Hills), and XI (Central and Eastern Forested Uplands).Phytoplankton chlorophyll a concentrations in lakes were related to total nitrogen, total phosphorus, Secchi depth, concentration of dissolved oxygen, pH, water temperature, and specific conductivity. In nutrient ecoregion VII, nutrients were not significant predictors of chlorophyll a concentrations. Total nitrogen, Secchi depth, and pH were significantly related to phytoplankton chlorophyll a concentrations in nutrient ecoregion IX. Lake periphyton chlorophyll a concentrations from nutrient ecoregion XI were related to total phosphorus rather than total nitrogen, Secchi depth, and pH. In all cases, Secchi depth was inversely related to the chlorophyll a concentrations in a lake. Nutrient ecoregion VIII had too few samples for any type of analysis.Streams within the different nutrient ecoregions had many variables that were significantly related to periphyton chlorophyll a concentrations. These variables consisted of total nitrogen, total phosphorus, drainage area, percent forest cover, several macroinvertebrate indices, pH, basin slope, total residue, total suspended solids, and water temperature. Nutrients were not significantly related to periphyton chlorophyll a in streams within nutrient ecoregions VII or IX but were in nutrient ecoregion XI. Drainage area, percent forest cover, and several invertebrate indices were significant variables in nutrient ecoregion VII. Percent forest cover and several invertebrate indices had a negative relation with chlorophyll a concentrations in these streams. Percent forest cover and basin slope had a negative effect on periphyton in nutrient ecoregion IX streams. Light availability was more critical to periphyton growth in streams than nutrients.Ecoregion XI had enough samples to do seasonal analyses. Summer-season periphyton chlorophyll a concentrations in nutrient ecoregion XI streams were positively related to total phosphorus and drainage area but negatively related to percent forest cover. Summer-season phytoplankton in streams was related to different variables within the same nutrient ecoregion. Both total nitrogen and total phosphorus were positively related with chlorophyll a concentrations as well as basin slope, total residue, and total suspended solids but negatively related to pH. The winter stream phytoplankton chlorophyll a concentrations were related to water temperature only.

Nutrient and chlorophyll relations in selected streams of the New England Coastal Basins in Massachusetts and New Hampshire, June-September 2001

USGS Publications Warehouse

Riskin, Melissa L.; Deacon, J.R.; Liebman, M.L.; Robinson, K.W.

2003-01-01

The U.S. Environmental Protection Agency is developing guidance to assist states with defining nutrient criteria for rivers and streams and to better describe nutrient-algal relations. As part of this effort, 13 wadeable stream sites were selected, primarily in eastern Massachusetts, for a nutrient-assessment study during the summer of 2001. The sites represent a range of water-quality impairment conditions (reference, moderately impaired, impaired) based on state regulatory agency assessments and previously assessed nitrogen, phosphorus, and dissolved-oxygen data. In addition, a combination of open- and closed-canopy locations were sampled at six of the sites to investigate the effect of sunlight on algal growth. Samples for nutrients and for chlorophyll I from phytoplankton and periphyton were collected at all stream sites. Total nitrogen (dissolved nitrite + nitrate + total ammonia + organic nitrogen) and total phosphorus (phosphorus in an unfiltered water sample) concentrations were lowest at reference sites and highest at impaired sites. There were statistically significant differences (p < 0.05) among reference, moderately impaired, and impaired sites for total nitrogen and total phosphorus. Chlorophyll a concentrations from phytoplankton were not significantly different among site impairment designations. Concentrations of chlorophyll a from periphyton were highest at nutrient-impaired open-canopy sites. Chlorophyll a concentrations from periphyton samples were positively correlated with total nitrogen and total phosphorus at the open- and closed-canopy sites. Correlations were higher at open-canopy sites (p < 0.05, rho = 0.64 to 0.71) than at closed-canopy sites (p < 0.05, rho = 0.36 to 0.40). Statistically significant differences in the median concentrations of chlorophyll a from periphyton samples were observed between the open- and closed-canopy sites (p < 0.05). Total nitrogen and total phosphorus data from moderately impaired and impaired sites in this study exceeded the preliminary U.S. Environmental Protection Agency nutrient criteria values for the coastal region of New England. In an effort to establish more appropriate nutrient and chlorophyll criteria for streams in the New England coastal region, relations between total nitrogen and total phosphorus to periphyton chlorophyll a in wadeable streams from this study were quantified to present potential techniques for determining nutrient concentrations. Linear regression was used to estimate the total nitrogen and total phosphorus concentrations that corresponded to various chlorophyll a concentrations. On the basis of this relation, a median concentration for moderately enriched streams of 21 milligrams per square meter (mg/m2) of periphyton chlorophyll a from the literature corresponded to estimated concentrations of 1.3 milligrams per liter (mg/L) for total nitrogen and 0.12 mg/L for total phosphorus. The median concentration for periphyton chlorophyll a from the literature is similar to the 50th-percentile concentration of periphyton chlorophyll a (17 mg/m2) calculated with the data from open-canopy sites in this study. The 25th-percentile concentration for periphyton chlorophyll a of all open-canopy sites (5.2 mg/m2) and the 75th-percentile concentration for periphyton chlorophyll a of open-canopy reference sites (16 mg/m2) also were plotted to provide additional estimates and methods for developing total nitrogen and total phosphorus criteria. The 25th-percentile concentrations of total nitrogen and total phosphorus were calculated based on all sites in this study and were used as another potential criteria estimation. A concentration of 0.64 mg/L for total nitrogen and 0.030 mg/L for total phosphorus were calculated. As another possible method to develop threshold concentrations, the 10th-percentile concentrations of total nitrogen and total phosphorus were calculated based on all the impaired sites in this study. A concentration threshold of 0

Determination of phytoplankton abundances (Chlorophyll-a) in the optically complex inland water - The Baltic Sea.

PubMed

Zhang, Daoxi; Lavender, Samantha; Muller, Jan-Peter; Walton, David; Karlson, Bengt; Kronsell, Johan

2017-12-01

A novel approach, termed Summed Positive Peaks (SPP), is proposed for determining phytoplankton abundances (Chlorophyll-a or Chl-a) and surface phytoplankton bloom extent in the optically complex Baltic Sea. The SPP approach is established on the basis of a baseline subtraction method using Rayleigh corrected top-of-atmosphere data from the Medium Resolution Imaging Spectrometer (MERIS) measurements. It calculates the reflectance differences between phytoplankton related signals observed in the MERIS red and near infrared (NIR) bands, such as sun-induced chlorophyll fluorescence (SICF) and the backscattering at 709nm, and considers the summation of the positive line heights for estimating Chl-a concentrations. The SPP algorithm is calibrated against near coincident in situ data collected from three types of phytoplankton dominant waters encountered in the Baltic Sea during 2010 (N=379). The validation results show that the algorithm is capable of retrieving Chl-a concentrations ranging from 0.5 to 3mgm -3 , with an RMSE of 0.24mgm -3 (R 2 =0.69, N=264). Additionally, the comparison results with several Chl-a algorithms demonstrates the robustness of the SPP approach and its sensitivity to low to medium biomass waters. Based on the red and NIR reflectance features, a flagging method is also proposed to distinguish intensive surface phytoplankton blooms from the background water. Copyright © 2017 Elsevier B.V. All rights reserved.

Controlling effects of mesoscale eddies on thermohaline structure and in situ chlorophyll distribution in the western North Pacific

NASA Astrophysics Data System (ADS)

Gao, Wei; Wang, Zhenyan; Zhang, Kainan

2017-11-01

Based on the conductivity, temperature and depth (CTD) data collected at 93 hydrographic stations during a marine cruise and on contemporary satellite altimeter observations, a series of eddies have been observed passing over the stratified upper water of the Parece Vela Basin. The results from hydrographic measurements and in situ chlorophyll fluorescence measurements have revealed that these eddies exerted significant controlling effects on the thermohaline structure and chlorophyll distribution, especially on the prevalent subsurface chlorophyll maximum layer (SCML). Based on these observations and particulate beam attenuation coefficient (cp) data, the in situ phytoplankton bloom around the pycnocline can be largely attributable to the formation of a well-developed SCML in the studied system. The uplift of the cold subsurface water within the cyclone, shoaling the pycnocline to a shallower layer, resulted in a low-temperature anomaly and different salinity anomalies at different depths. This uplift in the cyclone further caused the SCML to appear at a shallower depth with a higher in situ chlorophyll concentration than that in the normal domain. Conversely, the sinking of the warm surface water to the subsurface layer within the anticyclone depressed the pycnocline to a deeper layer and generated a high-temperature anomaly and opposite salinity anomalies compared with the cyclone. The sinking of the pycnocline within the anticyclone considerably influenced the characteristics of the SCML, which had a deeper depth and a lower in situ chlorophyll concentration than that of the normal sea. This study contributes rare quasi-synchronous CTD observations capturing mesoscale eddies and provides valuable descriptions of the variations in the SCML under the influence of mesoscale eddies based on in situ optical measurements from the seldom-discussed western North Pacific.

Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

NASA Astrophysics Data System (ADS)

Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

2014-06-01

Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

Leaf reflectance-nitrogen-chlorophyll relations among three south Texas woody rangeland plant species

NASA Technical Reports Server (NTRS)

Gausman, H. W.; Everitt, J. H.; Escobar, D. E. (Principal Investigator)

1982-01-01

Annual variations in the nitrogen-chlorophyll leaf reflectance of hackberry, honey mesquite and live oak in south Texas, were compared. In spring, leaf reflectance at the 0.55 m wavelength and nitrogen (N) concentration was high but leaf chlorophyll (chl) concentrations were low. In summer, leaf reflectance and N-concentration were low but lead chl concentrations were high. Linear correlations for both spring and summer of leaf reflectance with N and chl concentration or deviations from linear regression were not statistically significant.

Nanocolloids in Natural Water: Isolation, Characterization, and Toxicity.

PubMed

Ouyang, Shaohu; Hu, Xiangang; Zhou, Qixing; Li, Xiaokang; Miao, Xinyu; Zhou, Ruiren

2018-04-17

Nanocolloids are widespread in natural water systems, but their characterization and ecological risks are largely unknown. Herein, tangential flow ultrafiltration (TFU) was used to separate and concentrate nanocolloids from surface waters. Unexpectedly, nanocolloids were present in high concentrations ranging from 3.7 to 7.2 mg/L in the surface waters of the Harihe River in Tianjin City, China. Most of the nanocolloids were 10-40 nm in size, contained various trace metals and polycyclic aromatic hydrocarbons, and exhibited fluorescence properties. Envelopment effects and aggregation of Chlorella vulgaris in the presence of nanocolloids were observed. Nanocolloids entered cells and nanocolloid-exposed cells exhibited stronger plasmolysis, chloroplast damage and more starch grains than the control cells. Moreover, nanocolloids inhibited the cell growth, promoted reactive oxygen species (ROS), reduce the chlorophyll a content and increased the cell permeability. The genotoxicity of nanocolloids was also observed. The metabolomics analysis revealed a significant ( p < 0.05) downregulation of amino acids and upregulation of fatty acids contributing to ROS increase, chlorophyll a decrease and plasmolysis. The present work reveals that nanocolloids, which are different from specific, engineered nanoparticles (e.g., Ag nanoparticles), are present at high concentrations, exhibit an obvious toxicity in environments, and deserve more attention in the future.

Optimal Environmental Conditions and Anomalous Ecosystem Responses: Constraining Bottom-up Controls of Phytoplankton Biomass in the California Current System

PubMed Central

Jacox, Michael G.; Hazen, Elliott L.; Bograd, Steven J.

2016-01-01

In Eastern Boundary Current systems, wind-driven upwelling drives nutrient-rich water to the ocean surface, making these regions among the most productive on Earth. Regulation of productivity by changing wind and/or nutrient conditions can dramatically impact ecosystem functioning, though the mechanisms are not well understood beyond broad-scale relationships. Here, we explore bottom-up controls during the California Current System (CCS) upwelling season by quantifying the dependence of phytoplankton biomass (as indicated by satellite chlorophyll estimates) on two key environmental parameters: subsurface nitrate concentration and surface wind stress. In general, moderate winds and high nitrate concentrations yield maximal biomass near shore, while offshore biomass is positively correlated with subsurface nitrate concentration. However, due to nonlinear interactions between the influences of wind and nitrate, bottom-up control of phytoplankton cannot be described by either one alone, nor by a combined metric such as nitrate flux. We quantify optimal environmental conditions for phytoplankton, defined as the wind/nitrate space that maximizes chlorophyll concentration, and present a framework for evaluating ecosystem change relative to environmental drivers. The utility of this framework is demonstrated by (i) elucidating anomalous CCS responses in 1998–1999, 2002, and 2005, and (ii) providing a basis for assessing potential biological impacts of projected climate change. PMID:27278260

A 15-year global biogeochemical reanalysis with ocean colour data assimilation

NASA Astrophysics Data System (ADS)

Ford, David; Barciela, Rosa

2013-04-01

A continuous global time-series of remotely sensed ocean colour observations is available from 1997 to the present day. However coverage is incomplete, and limited to the sea surface. Models are therefore required to provide full spatial coverage, and to investigate the relationships between physical and biological variables and the carbon cycle. Data assimilation can then be used to constrain models to fit the observations, thereby combining the advantages of both sources of information. As part of the European Space Agency's Climate Change Initiative (ESA-CCI), we assimilate chlorophyll concentration derived from ocean colour observations into a coupled physical-biogeochemical model. The data assimilation scheme (Hemmings et al., 2008, J. Mar. Res.; Ford et al., 2012, Ocean Sci.) uses the information from the observations to update all biological and carbon cycle state variables within the model. Global daily reanalyses have been produced, with and without assimilation of merged ocean colour data provided by GlobColour, for the period September 1997 to August 2012. The assimilation has been shown to significantly improve the model's representation of chlorophyll concentration, at the surface and at depth. Furthermore, there is evidence of improvement to the representation of pCO2, nutrients and zooplankton concentration compared to in situ observations. We use the results to quantify recent seasonal and inter-annual variability in variables including chlorophyll concentration, air-sea CO2 flux and alkalinity. In particular, we explore the impact of physical drivers such as the El Niño Southern Oscillation (ENSO) on the model's representation of chlorophyll and the carbon cycle, and the pros and cons of the model reanalyses compared to observation-based climatologies. Furthermore, we perform a comparison between the GlobColour product and an initial version of a new merged product being developed as part of the ESA-CCI. Equivalent year-long hindcasts are performed with assimilation of each data set, and compared to a control run. Differences in the products are discussed, along with their impact on model accuracy compared to in situ observations, and the representation of the carbon cycle in each hindcast.

Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

NASA Technical Reports Server (NTRS)

Makinen, Carla; Moisan, Tiffany A. (Editor)

2012-01-01

As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

Seasonal and regional differentiation of bio-optical properties within the north polar Atlantic

NASA Astrophysics Data System (ADS)

Stramska, Malgorzata; Stramski, Dariusz; Kaczmarek, SłAwomir; Allison, David B.; Schwarz, Jill

2006-08-01

Using field data from the north polar Atlantic, we examined seasonal variability of the spectral absorption, a(λ), and backscattering, bb(λ), coefficients of surface waters in relation to phytoplankton pigments. For a given chlorophyll a concentration, the concentrations of accessory pigments were lower in spring than in summer. This effect contributed to lower chlorophyll-specific absorption of phytoplankton and total particulate matter in spring. The spring values of the green-to-blue band ratio of a(λ) were higher than the summer ratios. The blue-to-green ratios of bb(λ) were also higher in spring. The higher bb values and lower blue-to-green bb ratios in summer were likely associated with higher concentrations of detrital particles in summer compared to spring. Because the product of these band ratios of a and bb is a proxy for the blue-to-green ratio of remote-sensing reflectance, the performance of ocean color band-ratio algorithms for estimating pigments is significantly affected by seasonal shifts in the relationships between absorption, backscattering, and chlorophyll a. Our results suggest that the algorithm for the spring season would predict chlorophyll a that is higher by as much as a factor of 4-6 compared to that predicted from the summer algorithm. This indicates a need for a seasonal approach in the north polar Atlantic. However, we also found that a fairly good estimate of the particulate beam attenuation coefficient at 660 nm (a proxy for total particulate matter or particulate organic carbon concentration) can be obtained by applying a single blue-to-green band-ratio algorithm regardless of the season.

Coastal Atmosphere and Sea Time Series (CoASTS)

NASA Technical Reports Server (NTRS)

Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Berthon, Jean-Francoise; Zibordi, Giuseppe; Doyle, John P.; Grossi, Stefania; vanderLinde, Dirk; Targa, Cristina; McClain, Charles R. (Technical Monitor)

2002-01-01

In this document, the first three years of a time series of bio-optical marine and atmospheric measurements are presented and analyzed. These measurements were performed from an oceanographic tower in the northern Adriatic Sea within the framework of the Coastal Atmosphere and Sea Time Series (CoASTS) project, an ocean color calibration and validation activity. The data set collected includes spectral measurements of the in-water apparent (diffuse attenuation coefficient, reflectance, Q-factor, etc.) and inherent (absorption and scattering coefficients) optical properties, as well as the concentrations of the main optical components (pigment and suspended matter concentrations). Clear seasonal patterns are exhibited by the marine quantities on which an appreciable short-term variability (on the order of a half day to one day) is superimposed. This short-term variability is well correlated with the changes in salinity at the surface resulting from the southward transport of freshwater coming from the northern rivers. Concentrations of chlorophyll alpha and total suspended matter span more than two orders of magnitude. The bio-optical characteristics of the measurement site pertain to both Case-I (about 64%) and Case-II (about 36%) waters, based on a relationship between the beam attenuation coefficient at 660nm and the chlorophyll alpha concentration. Empirical algorithms relating in-water remote sensing reflectance ratios and optical components or properties of interest (chlorophyll alpha, total suspended matter, and the diffuse attenuation coefficient) are presented.

Wind effects on coastal zone color scanner chlorophyll patterns in the U.S. Mid-Atlantic Bight during spring 1979

NASA Technical Reports Server (NTRS)

Eslinger, David L.; Iverson, Richard L.

1986-01-01

Coastal zone color scanner (CZCS) chlorophyll concentration increases in the Mid-Atlantic Bight were associated with high wind speeds in continental shelf waters during March and May 1979. Maximum spring CZCS chlorophyll concentrations occurred during April when the water column was not thermally stratified and were spatially and temporally associated with reductions in wind speed both in onshelf and in offshelf regions. Increased chlorophyll concentrations in offshelf waters were associated with high wind speeds during May when a deep chlorophyll maximum was present. Chlorophyll patchiness was observed on length scales typical of those controlled by biological processes during the April low-wind period but not during March or May when wind speeds were greater. The spring CZCS chlorophyll maximum in the southern portion of the Mid-Atlantic Bight occurred in response to a reduction in mixed layer depth caused by decreased wind speeds and not by increased water column stratification.

Calibration of the Minolta SPAD-502 leaf chlorophyll meter.

PubMed

Markwell, J; Osterman, J C; Mitchell, J L

1995-01-01

Use of leaf meters to provide an instantaneous assessment of leaf chlorophyll has become common, but calibration of meter output into direct units of leaf chlorophyll concentration has been difficult and an understanding of the relationship between these two parameters has remained elusive. We examined the correlation of soybean (Glycine max) and maize (Zea mays L.) leaf chlorophyll concentration, as measured by organic extraction and spectrophotometric analysis, with output (M) of the Minolta SPAD-502 leaf chlorophyll meter. The relationship is non-linear and can be described by the equation chlorophyll (μmol m(-2))=10((M0.265)), r (2)=0.94. Use of such an exponential equation is theoretically justified and forces a more appropriate fit to a limited data set than polynomial equations. The exact relationship will vary from meter to meter, but will be similar and can be readily determined by empirical methods. The ability to rapidly determine leaf chlorophyll concentrations by use of the calibration method reported herein should be useful in studies on photosynthesis and crop physiology.

Preliminary study of internal wave effects to chlorophyll distribution in the Lombok Strait and adjacent areas

NASA Astrophysics Data System (ADS)

Arvelyna, Yessy; Oshima, Masaki

2005-01-01

This paper studies the effect of internal wave in the Lombok Strait to chlorophyll distribution in the surrounded areas using ERS SAR, ASTER, SeaWiFS and AVHRR-NOAA images data during 1996-2004 periods. The observation results shows that the internal waves were propagated to the south and the north of strait and mostly occurred during transitional season from dry to wet and wet season (rainy season) between September to December when the layers are strongly stratified. Wavelet transform of image using Meyer wavelet analysis is applied for internal wave detection in ERS SAR and ASTER images, for symmetric extension of data at the image boundaries, to prevent discontinuities by a periodic wrapping of data in fast algorithm and space-saving code. Internal wave created elongated pattern in detail and approximation of image from level 2 to 5 and retained value between 2-4.59 times compared to sea surface, provided accuracy in classification over than 80%. In segmentation process, the Canny edge detector is applied on the approximation image at level two to derive internal wave signature in image. The proposed method can extract the internal wave signature, maintain the continuity of crest line while reduce small strikes from noise. The segmentation result, i.e. the length between crest and trough, is used to compute the internal wave induced current using Korteweg-de Vries (KdV) equation. On ERS SAR data contains surface signature of internal wave (2001/8/20), we calculated that internal wave propagation speed was 1.2 m/s and internal wave induced current was 0.56 m/s, respectively. From the observation of ERS SAR and SeaWiFS images data, we found out that the distribution of maximum chlorophyll area at southern coastline off Bali Island when strong internal wave induced current occurred in south of the Lombok Strait was distributed further to westward, i.e. from 9.25°-10.25°LS, 115°-116.25°SE to 8.8°-10.7°LS, 114.5°-116°SE, and surface chlorophyll concentration near coastal area, i.e. area 8.8°-9.25° LS, 114.5°-115°SE, increased. The preliminary result of this study concludes that the internal waves presumably affect chlorophyll distribution to westward (from 9.25°-10.25°LS, 115°-116.25°SE to 8.8°-10.7°LS, 114.5°-116°SE) in the south coast off Bali Island and increase surface chlorophyll concentration near coastal area (8.8°-9.25° LS, 114.5°-115°SE).

Studies on kinetics of water quality factors to establish water transparency model in Neijiang River, China.

PubMed

Li, Ronghui; Pan, Wei; Guo, Jinchuan; Pang, Yong; Wu, Jianqiang; Li, Yiping; Pan, Baozhu; Ji, Yong; Ding, Ling

2014-05-01

The basis for submerged plant restoration in surface water is to research the complicated dynamic mechanism of water transparency. In this paper, through the impact factor analysis of water transparency, the suspended sediment, dissolved organic matter, algae were determined as three main impactfactors for water transparency of Neijiang River in Eastern China. And the multiple regression equation of water transparency and sediment concentration, permanganate index, chlorophyll-a concentration was developed. Considering the complicated transport and transformation of suspended sediment, dissolved organic matter and algae, numerical model of them were developed respectively for simulating the dynamic process. Water transparency numerical model was finally developed by coupling the sediment, water quality, and algae model. These results showed that suspended sediment was a key factor influencing water transparency of Neijiang River, the influence of water quality indicated by chemical oxygen demand and algal concentration indicated by chlorophyll a were indeterminate when their concentrations were lower, the influence was more obvious when high concentrations are available, such three factors showed direct influence on water transparency.

Remote sensing of oligotrophic waters: model divergence at low chlorophyll concentrations.

PubMed

Mehrtens, Hela; Martin, Thomas

2002-11-20

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(-3), whereas for lower chlorophyll concentrations we found a significant overestimation of the OC2 algorithm.

A study of the Alboran sea mesoscale system by means of empirical orthogonal function decomposition of satellite data

NASA Astrophysics Data System (ADS)

Baldacci, A.; Corsini, G.; Grasso, R.; Manzella, G.; Allen, J. T.; Cipollini, P.; Guymer, T. H.; Snaith, H. M.

2001-05-01

This paper presents the results of a combined empirical orthogonal function (EOF) analysis of Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) data and sea-viewing wide field-of-view sensor (SeaWiFS) chlorophyll concentration data over the Alboran Sea (Western Mediterranean), covering a period of 1 year (November 1997-October 1998). The aim of this study is to go beyond the limited temporal extent of available in situ measurements by inferring the temporal and spatial variability of the Alboran Gyre system from long temporal series of satellite observations, in order to gain insight on the interactions between the circulation and the biological activity in the system. In this context, EOF decomposition permits concise and synoptic representation of the effects of physical and biological phenomena traced by SST and chlorophyll concentration. Thus, it is possible to focus the analysis on the most significant phenomena and to understand better the complex interactions between physics and biology at the mesoscale. The results of the EOF analysis of AVHRR-SST and SeaWiFS-chlorophyll concentration data are presented and discussed in detail. These improve and complement the knowledge acquired during the in situ observational campaigns of the MAST-III Observations and Modelling of Eddy scale Geostrophic and Ageostrophic motion (OMEGA) Project.

Physical forcing of late summer chlorophyll a blooms in the oligotrophic eastern North Pacific

NASA Astrophysics Data System (ADS)

Toyoda, Takahiro; Okamoto, Suguru

2017-03-01

We investigated physical forcing of late summer chlorophyll a (chl a) blooms in the oligotrophic eastern North Pacific Ocean by using ocean reanalysis and satellite data. Relatively large chl a blooms as defined in this study occurred in August-October following sea surface temperature (SST) anomaly (SSTA) decreases, mixed layer deepening, and temperature and salinity increases at the bottom of the mixed layer. These physical conditions were apparently induced by the entrainment of subsurface water resulting from the destabilization of the surface layer caused by anomalous northward Ekman transport of subtropical waters of higher salinity. Salinity-normalized total alkalinity data provide supporting evidence for nutrient supply by the entrainment process. We next investigated the impact of including information about the entrainment on bloom identification. The results of analyses using reanalysis data and of those using only satellite data showed large SSTA decreases when the northward Ekman salinity transports were large, implying that the entrainment of subsurface water is well represented in both types of data. After surface-destabilizing conditions were established, relatively high surface chl a concentrations were observed. The use of SST information can further improve the detection of high chl a concentrations. Although the detection of high chl a concentrations would be enhanced by finer data resolution and the inclusion of biogeochemical parameters in the ocean reanalysis, our results obtained by using existing reanalysis data as well as recent satellite data are valuable for better understanding and prediction of lower trophic ecosystem variability.

Role of physical processes in chlorophyll distribution in the western tropical Indian Ocean

NASA Astrophysics Data System (ADS)

George, Jenson V.; Nuncio, M.; Chacko, Racheal; Anilkumar, N.; Noronha, Sharon B.; Patil, Shramik M.; Pavithran, Sini; Alappattu, Denny P.; Krishnan, K. P.; Achuthankutty, C. T.

2013-03-01

Physical control of the chlorophyll a (chl a) distribution in the western tropical Indian Ocean (WTIO, 8°N to 18°S along 65°E) was studied during the 2008 winter monsoon (WM) and the 2009 summer monsoon (SM). During both seasons, a prominent deep chlorophyll maximum (DCM, 0.3-0.5 mg m- 3) was observed at all stations between 8°N and 10°S in the depth range of 50-75 m, but south of 10°S, this phenomenon was observed as deeper (~ 120 m) and relatively weak (0.15-0.3 mg m- 3). During the SM, in addition to seasonal forcing, eddies and a freshened surface layer also played major roles in controlling the DCM and the surface chl a concentrations in the southern Arabian Sea and the equatorial Indian Ocean. During the WM, surface freshening controlled the chl a distribution in the Seychelles Chagos Thermocline Ridge (SCTR, 5°S-10°S) region by modulating the static stability and mixed layer depth. It appears that the surface freshening in this region is associated with the core of the South Equatorial Current. South of the SCTR, the chl a distribution was predominantly determined by the anti-cyclonic eddies in both seasons. The spatial patterns of the Sea Level Anomaly (SLA) followed most of the thermocline features observed during the study period.

Surface microlayer enrichment of polycyclic aromatic hydrocarbons in lower Chesapeake Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, K.; Dickhut, R.M.

1995-12-31

Surface microlayer samples were collected with a rotating cylinder sampler in the York River and Elizabeth River tributaries of lower Chesapeake Bay every other month from May 1994 to June, 1995. Spatial and temporal variabilities were also investigated over an annual cycle as well as shorter periods (i.e. days). All the samples were analyzed for 17 polycyclic aromatic hydrocarbons, total suspended particulate matter (TSP), particular organic carbon (POC), total nitrogen(TN) and dissolved organic carbon (DOC), and selected samples for chlorophyll. TSP in the surface microlayer was 10 to 100 times higher than that in the related bulk water. Particle associatedmore » PAH concentrations were 20--50 times those in bulk surface water, whereas PAH concentrations in freely dissolved phase of the surface microlayer were 5--60 times higher than dissolved concentrations in the bulk water. Particulate PAH concentrations increase with TSP in the surface microlayer and dissolved PAH concentrations increase with DOC. Overall, surface microlayer characteristics were found to be significantly affected by hydrological and meteorological parameters.« less

Determination of phytoplankton chlorophyll concentrations in the Chesapeake Bay with aircraft remote sensing

NASA Technical Reports Server (NTRS)

Harding, Lawrence W., Jr.; Itsweire, Eric C.; Esaias, Wayne E.

1992-01-01

Remote sensing measurements of the distribution of phytoplankton chlorophyll concentrations in Chesapeake Bay during 1989 are described. It is shown that remote sensing from light aircraft can complement and extend measurements made from traditional platforms and provide data of improved temporal and spatial resolution, leading to a better understanding of phytoplankton dynamics in the estuary. The developments of the winter-spring diatom bloom in the polyhaline to mesohaline regions of the estuary and of the late-spring and summer dinoflagellate blooms in oligohaline and mesohaline regions are traced. The study presents the local chlorophyll algorithm developed using the NASA Ocean Data Acquisition System data and in situ chlorophyll data, interpolated maps of chlorophyll concentration generated by applying the algorithm to aircraft radiance data, ancillary in situ data on nutrients, turbidity, streamflow, and light availability, and an interpretation of phytoplankton dynamics in terms of the chlorophyll distribution in Chesapeake Bay during 1989.

Temporal variability in phytoplankton pigments, picoplankton and coccolithophores along a transect through the North Atlantic and tropical southwestern Pacific

NASA Astrophysics Data System (ADS)

Dandonneau, Yves; Montel, Yves; Blanchot, Jean; Giraudeau, Jacques; Neveux, Jacques

2006-04-01

Biogeochemical processes in the sea are triggered in various ways by chlorophyll-containing phytoplankton groups. While the variability of chlorophyll concentration at sea has been observed from satellites for several years, these groups are known only from cruises which are limited in space and time. The Geochemistry, Phytoplankton and Color of the Ocean programme (GeP&CO) was set up to describe and understand the variability of phytoplankton composition on large spatial scales under a multi-year sampling strategy. It was based on sea-surface sampling along the route of the merchant ship Contship London which travelled four times a year from Le Havre (France) to Nouméa (New Caledonia) via New York, Panama and Auckland. Observations included the measurement of photosynthetic pigments, counts of picoplanktonic cells by flow cytometry (Prochlorococcus, Synechococcus, and picoeucaryotes) and counting and identification of coccolithophores. The results confirmed that tropical areas have low seasonal variability and are characterized by relatively high divinyl-chlorophyll a and zeaxanthin concentration and that the variability is strongest at high latitudes where the phytoplankton biomass and population structure are found to have large seasonal cycles. Thus, the spring bloom in the North Atlantic and an austral winter bloom north of New Zealand are marked by chlorophyll concentrations which are often higher than 0.5 μg l -1 and by high concentration of fucoxanthin (a pigment used as an indicator for diatoms), while summer populations are dominated by Prochlorococcus sp. and have low chlorophyll concentrations. Apart from this yearly bloom at temperate latitudes, fucoxanthin is scarce, except in the equatorial upwelling zone in the eastern Pacific Ocean, where it is found in moderate amounts. In this region, relatively high chlorophyll concentrations extend generally as far as 14°S and do not respond to the seasonal strengthening of the equatorial upwelling during the austral winter. Prochlorococcus, which is known to dominate in oligotrophic tropical seas and to disappear in cold conditions, in fact has its minimum during the spring bloom in the North Atlantic, rather than during the winter. Coccolithophores are ubiquitous, showing a succession of species in response to oceanic conditions and provinces. 19'Hexanoyloxyfucoxanthin, the pigment generally considered as an indicator of coccolithophores, is relatively abundant at all times and in all regions, but its abundance is generally not tightly correlated with that of coccolithophores. The regional differences revealed by these results are in overall agreement with Longhurst's division of the ocean into ecological provinces.

Response of Grape Leaf Spectra to Phylloxera Infestation

NASA Technical Reports Server (NTRS)

Johnson, Lee F.

1999-01-01

During the 1993 growing season, leaf reflectance and chlorophyll concentrations were monitored with respect to phylloxera (root-louse) infestation in a Napa Valley (California) vineyard. Study plots were established in areas of severely infested, mildly infested, and uninfested sections of the vineyard. A handheld chlorophyll meter, measuring leaf transmittance of near-infrared and red light, confirmed that reduced foliar chlorophyll concentrations were symptomatic of phylloxera stress in the sample vines. Bidirectional reflectance measurements of green and near-infrared light, taken on fresh leaves with a laboratory spectrophotometer, were related to chlorophyll concentration but did not allow discrimination of mildly infested from uninfested vines.

Observational insights into chlorophyll distributions of subtropical South Indian Ocean eddies

NASA Astrophysics Data System (ADS)

Dufois, François; Hardman-Mountford, Nick J.; Fernandes, Michelle; Wojtasiewicz, Bozena; Shenoy, Damodar; Slawinski, Dirk; Gauns, Mangesh; Greenwood, Jim; Toresen, Reidar

2017-04-01

The South Indian Ocean subtropical gyre has been described as a unique environment where anticyclonic ocean eddies highlight enhanced surface chlorophyll in winter. The processes responsible for this chlorophyll increase in anticyclones have remained elusive, primarily because previous studies investigating this unusual behavior were mostly based on satellite data, which only views the ocean surface. Here we present in situ data from an oceanographic voyage focusing on the mesoscale variability of biogeochemical variables across the subtropical gyre. During this voyage an autonomous biogeochemical profiling float transected an anticyclonic eddy, recording its physical and biological state over a period of 6 weeks. We show that several processes might be responsible for the eddy/chlorophyll relationship, including horizontal advection of productive waters and deeper convective mixing in anticyclonic eddies. While a deep chlorophyll maximum is present in the subtropical Indian Ocean outside anticyclonic eddies, mixing reaches deeper in anticyclonic eddy cores, resulting in increased surface chlorophyll due to the stirring of the deep chlorophyll maximum and possibly resulting in new production from nitrate injection below the deep chlorophyll maximum.

Summary of Surface-Water Quality Data from the Illinois River Basin in Northeast Oklahoma, 1970-2007

USGS Publications Warehouse

Andrews, William J.; Becker, Mark F.; Smith, S. Jerrod; Tortorelli, Robert L.

2009-01-01

The quality of streams in the Illinois River Basin of northeastern Oklahoma is potentially threatened by increased quantities of wastes discharged from increasing human populations, grazing of about 160,000 cattle, and confined animal feeding operations raising about 20 million chickens. Increasing numbers of humans and livestock in the basin contribute nutrients and bacteria to surface water and groundwater, causing greater than the typical concentrations of those constituents for this region. Consequences of increasing contributions of these substances can include increased algal growth (eutrophication) in streams and lakes; impairment of habitat for native aquatic animals, including desirable game fish species; impairment of drinking-water quality by sediments, turbidity, taste-and-odor causing chemicals, toxic algal compounds, and bacteria; and reduction in the aesthetic quality of the streams. The U.S. Geological Survey, in cooperation with the Oklahoma Scenic Rivers Commission, prepared this report to summarize the surface-water-quality data collected by the U.S. Geological Survey at five long-term surface-water-quality monitoring sites. The data summarized include major ions, nutrients, sediment, and fecal-indicator bacteria from the Illinois River Basin in Oklahoma for 1970 through 2007. General water chemistry, concentrations of nitrogen and phosphorus compounds, chlorophyll-a (an indicator of algal biomass), fecal-indicator bacteria counts, and sediment concentrations were similar among the five long-term monitoring sites in the Illinois River Basin in northeast Oklahoma. Most water samples were phosphorus-limited, meaning that they contained a smaller proportion of phosphorus, relative to nitrogen, than typically occurs in algal tissues. Greater degrees of nitrogen limitation occurred at three of the five sites which were sampled back to the 1970s, probably due to use of detergents containing greater concentrations of phosphorus than in subsequent periods. Concentrations of nitrogen, phosphorus, and sediment, and counts of bacteria generally increased with streamflow at the five sites, probably due to runoff from the land surface and re-suspension of streambed sediments. Phosphorus concentrations typically exceeded the Oklahoma standard of 0.037 milligrams per liter for Scenic Rivers. Concentrations of chlorophyll-a in phytoplankton in water samples collected at the five sites were not well correlated with streamflow, nor to concentrations of the nutrients nitrogen and phosphorus, probably because much of the algae growing in these streams are periphyton attached to streambed cobbles and other debris, rather than phytoplankton in the water column. Sediment concentrations correlated with phosphorus concentrations in water samples collected at the sites, probably due to sorption of phosphorus to soil particles and streambed sediments and runoff of soils and animal wastes at the land surface and resuspension of streambed sediments and phosphorus during wet, high-flow periods. Fecal coliform bacteria counts at the five sites sometimes exceeded the Oklahoma Primary Body Contact Standard of 400 colonies per 100 milliliters when streamflows were greater than 1000 cubic feet per second. Ultimately, Lake Tenkiller, an important ecological and economic resource for the region, receives the compounds that runoff the land surface or seep to local streams from groundwater in the basin. Because of eutrophication from increased nutrient loading, Lake Tenkiller is listed for impairment by diminished dissolved oxygen concentrations, phosphorus, and chlorophyll-a by the State of Oklahoma in evaluation of surface-water quality required by section 303d of the Clean Water Act. Stored phosphorus in soils and streambed and lakebed sediments may continue to provide phosphorus to local streams and lakes for decades to come. Steps are being made to reduce local sources of phosphorus, including upgrades in capacity and effective

Factors Influencing Nitrogen-Chorophyll Relationships for Ten Estuaries on the U.S. Atlantic and Gulf of Mexico Coasts (NEERS 08)

EPA Science Inventory

Regression relationships between summer concentrations of total (inorganic + organic) nitrogen and phytoplankton chlorophyll a in surface water have been developed for nine estuaries on the U.S. Atlantic coast and one adjacent to the Gulf of Mexico. Four of these systems are estu...

Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

NASA Technical Reports Server (NTRS)

Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

2004-01-01

We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

Ocean-color remote sensing of the Nile delta shelf and SE Levantine basin and possible linkage to some mesoscale circulation features and Nile river run-off

NASA Astrophysics Data System (ADS)

Moufaddal, Wahid; Lavender, Samantha

To date, and despite the passage of more than 30 years since the launch of the first satellite based ocean-color sensor, no systematic study of the variability of chlorophyll in the Egyptian Mediterranean coast off the Nile delta has been undertaken using this kind of data. Meantime, available in-situ measurements on chlorophyll and other nutrient parameters along this coast are indeed very modest and scarce. The lack of data has in turn created a large gap in our knowledge on the biogeochemical characteristics of the coastal water and impacts of the Aswan High Dam and other land-use changes on the marine ecosystems and nutrient budget in the Nile delta shelf and the SE Mediterranean. The present study aims to fill part of this gap through application of ocean-color remote sensing and satellite retrieval of phytoplankton chlorophyll. For this purpose a 10-year (1997-2006) monthly satellite dataset from ESA Globcolour project (an ESA Data User Element project: http://www.globcolour.info) was retrieved and subjected to time-series analysis. Results of this analysis revealed that the oceanic and coastal parts off the Nile delta coast and SE Mediterranean manifest from time to time some of the most interesting and dynamical marine features including meso-scale gyres, coastal filaments, localized algal blooms and higher concentration of phytoplankton chlorophyll. These features together with certain physical pro-cesses and surface run-off from Nile mouthes and other land-based sources were found to exert pronounced effects on the nutrient supply and quality of the coastal and oceanic surface waters in this region. Results reveled also that there has been a general upward trend in concentration of surface chlorophyll during the 10-year period from 1997 to 2006 with a coincident rise of the coastal fisheries implying that improvement of nutrient supply is most likely responsible for this rise. Results confirmed also shift of the Nile phytoplankton bloom in space and time after construc-tion of the Aswan High Dam and other subsequent anthropogenic activities Conclusions and results achieved by this study show the importance of ocean-color satellite data for monitoring of biogeochemical impacts of land-use changes on coastal ecosystems and the role which it can play in assessment of the marine productivity and state of the marine fisheries.

Multi-sensor satellite and in situ monitoring of phytoplankton development in a eutrophic-mesotrophic lake.

PubMed

Dörnhöfer, Katja; Klinger, Philip; Heege, Thomas; Oppelt, Natascha

2018-01-15

Phytoplankton indicated by its photosynthetic pigment chlorophyll-a is an important pointer on lake ecology and a regularly monitored parameter within the European Water Framework Directive. Along with eutrophication and global warming cyanobacteria gain increasing importance concerning human health aspects. Optical remote sensing may support both the monitoring of horizontal distribution of phytoplankton and cyanobacteria at the lake surface and the reduction of spatial uncertainties associated with limited water sample analyses. Temporal and spatial resolution of using only one satellite sensor, however, may constrain its information value. To discuss the advantages of a multi-sensor approach the sensor-independent, physically based model MIP (Modular Inversion and Processing System) was applied at Lake Kummerow, Germany, and lake surface chlorophyll-a was derived from 33 images of five different sensors (MODIS-Terra, MODIS-Aqua, Landsat 8, Landsat 7 and Sentinel-2A). Remotely sensed lake average chlorophyll-a concentration showed a reasonable development and varied between 2.3±0.4 and 35.8±2.0mg·m -3 from July to October 2015. Match-ups between in situ and satellite chlorophyll-a revealed varying performances of Landsat 8 (RMSE: 3.6 and 19.7mg·m -3 ), Landsat 7 (RMSE: 6.2mg·m -3 ), Sentinel-2A (RMSE: 5.1mg·m -3 ) and MODIS (RMSE: 12.8mg·m -3 ), whereas an in situ data uncertainty of 48% needs to be respected. The temporal development of an index on harmful algal blooms corresponded well with the cyanobacteria biomass development during summer months. Satellite chlorophyll-a maps allowed to follow spatial patterns of chlorophyll-a distribution during a phytoplankton bloom event. Wind conditions mainly explained spatial patterns. Integrating satellite chlorophyll-a into trophic state assessment resulted in different trophic classes. Our study endorsed a combined use of satellite and in situ chlorophyll-a data to alleviate weaknesses of both approaches and to better characterise and understand phytoplankton development in lakes. Copyright © 2017 Elsevier B.V. All rights reserved.

Inhibition of chlorophyll synthesis and carotenoid accumulation by manganese and cobalt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clairmont, K.B.; Davis, E.; Hagar, W.

1986-05-01

The authors have developed methods for the separation and identification of the major pigments of the photosynthetic apparatus in plants using reversed phase microbore high performance liquid chromatography. Using these methods they have monitored the concentrations of pigments in tissue cultured tobacco callus in the absence and presence of excess manganese and cobalt. Manganese and cobalt were reported to inhibit chlorophyll synthesis in blue green algae. They have found that excess manganese blocks chlorophyll synthesis in tobacco callus also. In the manganese inhibited callus there is an increase in the concentration of protoporphyrin IX- the last common precursor to bothmore » the chlorophyll and heme synthetic pathways. They have found that cobalt also blocks chlorophyll synthesis in tissue cultured tobacco callus, but at a much lower concentration. In addition to the inhibition of chlorophyll synthesis by excess manganese and cobalt, the accumulation of carotenoids is reduced by several orders of magnitude in this tissue. The absence of chlorophyll may prevent assembly of any components of the photosynthetic apparatus in these cells.« less

Spatial-temporal distribution of phytoplankton pigments in relation to nutrient status in Jiaozhou Bay, China

NASA Astrophysics Data System (ADS)

Yao, Peng; Yu, Zhigang; Deng, Chunmei; Liu, Shuxia; Zhen, Yu

2010-10-01

We conducted studies of phytoplankton and hydrological variables in a semi-enclosed bay in northern China to understand the spatial-temporal variability and relationship between these variables. Samples were collected during seven cruises in Jiaozhou Bay from November 2003 to October 2004, and were analyzed for temperature, nutrients and phytoplankton pigments. Pigments from eight possible phytoplankton classes (Diatoms, Dinoflagellates, Chlorophyceae, Prasinophyceae, Chrysophyceae, Haptophyceae, Cryptophyceae and Caynophyceae) were detected in surface water by high performance liquid chromatography (HPLC). Phytoplankton pigment and nutrient concentrations in Jiaozhou Bay were spatially and temporally variable, and most of them were highest in the northern and eastern parts of the sampling regions in spring (May) and summer (August), close to areas of shellfish culturing, river estuaries, dense population and high industrialization, reflecting human activities. Chlorophyll a was recorded in all samples, with an annual mean concentration of 1.892 μg L -1, and fucoxanthin was the most abundant accessory pigment, with a mean concentration of 0.791 μg L -1. The highest concentrations of chlorophyll a (15.299 μg L -1) and fucoxanthin (9.417 μg L -1) were observed in May 2004 at the station close to the Qingdao Xiaogang Ferry, indicating a spring bloom of Diatoms in this area. Although chlorophyll a and other biomarker pigments showed significant correlations, none of them showed strong correlations with temperature and nutrients, suggesting an apparent de-coupling between the pigments and these hydrological variables. The nutrient composition and phytoplankton community composition of Jiaozhou Bay have changed significantly in the past several decades, reflecting the increasing nutrient concentrations and decline of phytoplankton cell abundance. The unchanged total chlorophyll a levels indicated that smaller species have filled the niche vacated by the larger species in Jiaozhou Bay, as revealed by our biomarker pigment analysis.

Coastal Zone Color Scanner data of rich coastal waters

NASA Technical Reports Server (NTRS)

Wrigley, R. C.; Klooster, S. A.

1983-01-01

Comparisons of chlorophyll concentrations and diffuse attenuation coefficients measured from ships off the central California coast were made with satellite derived estimates of the same parameters using data from the Coastal Zone Color Scanner. Very high chlorophyll concentrations were encountered in Monterey Bay. Although lower chlorophyll values acquired off Pt. Sur agreed satisfactorily with the satellite data, the high chlorophyll values departed markedly from agreement. Two possible causes for the disagreement are suggested. Comparison of diffuse attenuation coefficients from the same data sets showed closer agreement.

Phytomonitoring of air pollution around a thermal power plant

NASA Astrophysics Data System (ADS)

Agrawal, M.; Agrawal, S. B.

This study was undertaken in order to assess the impact of air pollutants on vegetation around Obra thermal power plant (1550 M W capacity) in the Mirzapur district of Uttar Pradesh. For this purpose, Mangifera indica, Citrus medico and Bouganvillaea spectabilis plants, most common at all sites, were selected as test plants. Five study sites were selected northeast (prevailing wind) of the thermal power plant. A control site was also selected at a distance of 30 km north of Obra. Responses of plants to pollutants in terms of presence of foliar injury symptoms and changes in chlorophyll, ascorbic acid and S content were measured. These changes were correlated with ambient SO 2 and suspended particulate matter (SPM) concentrations and the amount of dust settled on leaf surfaces. The SO 2 and SPM concentrations were quite high in the immediate vicinity of the power plant. There also exists a direct relationship between the concentration of SPM in air and amount of dust deposited on leaf surfaces. Maximum dust deposition was observed on M. indica plants. The levels of foliar injury, chlorophyll and ascorbic acid were found to decrease and that of S increase in plants around the power plant in comparison to those growing at a control site. The magnitude of such changes was maximum in M. indica and minimum in C. medica. A species specific direct relationship between the increase in the amount of S and decrease in chlorophyll content was observed. The study suggests that differential sensitivity of plants to SO 2 may be used in evaluating the air pollution impact around emission sources and M. indica plants can be used as an indicator plant for quantifying biological changes.

Light attenuation and submersed macrophyte distribution in the tidal Potomac River and estuary

USGS Publications Warehouse

Carter, V.; Rybicki, N.B.

1990-01-01

Changing light availability may be responsible for the discontinuous distribution of submersed aquatic macrophytes in the freshwater tidal Potomac River. During the 1985-1986 growing seasons, light attenuation and chlorophyll a and suspended particulate material concentrations were measured in an unvegetated reach (B) and in two adjacent vegetated reaches (A and C). Light attenuation in reach B (the lower, fresh to oligohaline tidal river) was greater than that in reach A (the recently revegetated, upper, freshwater tidal river) in both years. Reach B light attenuation was greater than that in reach C (the vegetated, oligohaline to mesohaline transition zone of the Potomac Estuary) in 1985 and similar to that in reach C in 1986. In reach B, 5% of total below-surface light penetrated only an average of 1.3 m in 1985 and 1.0m in 1986, compared with 1.9 m and 1.4 m in reach A in 1985 and 1986, respectively. Water column chlorophyll a concentration controlled light availability in reaches A and B in 1985, whereas both chlorophyll a and suspended particulate material concentrations were highly correlated with attenuation in both reaches in 1986. Reach C light attenuation was correlated with suspended particulate material in 1986. The relationship between attenuation coefficient and Secchi depth was KPAR=1.38/Secchi depth. The spectral distribution of light at 1 m was shifted toward the red portion of the visible spectrum compared to surface light. Blue light was virtually absent at 1.0 m in reach B during July and August 1986. Tidal range is probably an important factor in determining light availability for submersed macrophyte propagule survival at the sediment-water interface in this shallow turbid system. ?? 1990 Estuarine Research Federation.

Development of a 3D coupled physical-biogeochemical model for the Marseille coastal area (NW Mediterranean Sea): what complexity is required in the coastal zone?

PubMed

Fraysse, Marion; Pinazo, Christel; Faure, Vincent Martin; Fuchs, Rosalie; Lazzari, Paolo; Raimbault, Patrick; Pairaud, Ivane

2013-01-01

Terrestrial inputs (natural and anthropogenic) from rivers, the atmosphere and physical processes strongly impact the functioning of coastal pelagic ecosystems. The objective of this study was to develop a tool for the examination of these impacts on the Marseille coastal area, which experiences inputs from the Rhone River and high rates of atmospheric deposition. Therefore, a new 3D coupled physical/biogeochemical model was developed. Two versions of the biogeochemical model were tested, one model considering only the carbon (C) and nitrogen (N) cycles and a second model that also considers the phosphorus (P) cycle. Realistic simulations were performed for a period of 5 years (2007-2011). The model accuracy assessment showed that both versions of the model were able of capturing the seasonal changes and spatial characteristics of the ecosystem. The model also reproduced upwelling events and the intrusion of Rhone River water into the Bay of Marseille well. Those processes appeared to greatly impact this coastal oligotrophic area because they induced strong increases in chlorophyll-a concentrations in the surface layer. The model with the C, N and P cycles better reproduced the chlorophyll-a concentrations at the surface than did the model without the P cycle, especially for the Rhone River water. Nevertheless, the chlorophyll-a concentrations at depth were better represented by the model without the P cycle. Therefore, the complexity of the biogeochemical model introduced errors into the model results, but it also improved model results during specific events. Finally, this study suggested that in coastal oligotrophic areas, improvements in the description and quantification of the hydrodynamics and the terrestrial inputs should be preferred over increasing the complexity of the biogeochemical model.

Development of a 3D Coupled Physical-Biogeochemical Model for the Marseille Coastal Area (NW Mediterranean Sea): What Complexity Is Required in the Coastal Zone?

PubMed Central

Fraysse, Marion; Pinazo, Christel; Faure, Vincent Martin; Fuchs, Rosalie; Lazzari, Paolo; Raimbault, Patrick; Pairaud, Ivane

2013-01-01

Terrestrial inputs (natural and anthropogenic) from rivers, the atmosphere and physical processes strongly impact the functioning of coastal pelagic ecosystems. The objective of this study was to develop a tool for the examination of these impacts on the Marseille coastal area, which experiences inputs from the Rhone River and high rates of atmospheric deposition. Therefore, a new 3D coupled physical/biogeochemical model was developed. Two versions of the biogeochemical model were tested, one model considering only the carbon (C) and nitrogen (N) cycles and a second model that also considers the phosphorus (P) cycle. Realistic simulations were performed for a period of 5 years (2007–2011). The model accuracy assessment showed that both versions of the model were able of capturing the seasonal changes and spatial characteristics of the ecosystem. The model also reproduced upwelling events and the intrusion of Rhone River water into the Bay of Marseille well. Those processes appeared to greatly impact this coastal oligotrophic area because they induced strong increases in chlorophyll-a concentrations in the surface layer. The model with the C, N and P cycles better reproduced the chlorophyll-a concentrations at the surface than did the model without the P cycle, especially for the Rhone River water. Nevertheless, the chlorophyll-a concentrations at depth were better represented by the model without the P cycle. Therefore, the complexity of the biogeochemical model introduced errors into the model results, but it also improved model results during specific events. Finally, this study suggested that in coastal oligotrophic areas, improvements in the description and quantification of the hydrodynamics and the terrestrial inputs should be preferred over increasing the complexity of the biogeochemical model. PMID:24324589

Predictability and environmental drivers of chlorophyll fluctuations vary across different time scales and regions of the North Sea

NASA Astrophysics Data System (ADS)

Blauw, Anouk N.; Benincà, Elisa; Laane, Remi W. P. M.; Greenwood, Naomi; Huisman, Jef

2018-02-01

Phytoplankton concentrations display strong temporal variability at different time scales. Recent advances in automated moorings enable detailed investigation of this variability. In this study, we analyzed phytoplankton fluctuations at four automated mooring stations in the North Sea, which measured phytoplankton abundance (chlorophyll) and several environmental variables at a temporal resolution of 12-30 min for two to nine years. The stations differed in tidal range, water depth and freshwater influence. This allowed comparison of the predictability and environmental drivers of phytoplankton variability across different time scales and geographical regions. We analyzed the time series using wavelet analysis, cross correlations and generalized additive models to quantify the response of chlorophyll fluorescence to various environmental variables (tidal and meteorological variables, salinity, suspended particulate matter, nitrate and sea surface temperature). Hour-to-hour and day-to-day fluctuations in chlorophyll fluorescence were substantial, and mainly driven by sinking and vertical mixing of phytoplankton cells, horizontal transport of different water masses, and non-photochemical quenching of the fluorescence signal. At the macro-tidal stations, these short-term phytoplankton fluctuations were strongly driven by the tides. Along the Dutch coast, variation in salinity associated with the freshwater influence of the river Rhine played an important role, while in the central North Sea variation in weather conditions was a major determinant of phytoplankton variability. At time scales of weeks to months, solar irradiance, nutrient conditions and thermal stratification were the dominant drivers of changes in chlorophyll concentrations. These results show that the dominant drivers of phytoplankton fluctuations differ across marine environments and time scales. Moreover, our findings show that phytoplankton variability on hourly to daily time scales should not be dismissed as environmental noise, but is related to vertical and horizontal particle transport driven by winds and tides. Quantification of these transport processes contributes to an improved predictability of marine phytoplankton concentrations.

Quantifying Foliar Pigment Concentrations of Temperate Forest Species Using Digital Photography and Hyperspectral Reflectance Indices

NASA Astrophysics Data System (ADS)

Gagnon, M. T.; Rock, B. N.; Jahnke, L. S.; Lee, T. D.

2008-12-01

Determination of leaf chlorophyll content is a common and important procedure for plant scientists. There are many multispectral techniques for non destructive in-vivo, estimation of chlorophyll in foliage. Although much has been done to explore the estimation of foliar pigments using remote sensing, very little work has been done exploring the potential that basic, affordable, digital cameras may have for such analysis. This study utilizes a combination of digital photography, hyperspectral laboratory remote sensing, and chlorophyll extractions to determine if digital photographs can be used to accurately predict foliar chlorophyll concentrations as well to compare this digital approach with several common spectral indices used for estimating foliar chlorophyll content. Foliar materials for this study come from three sources. A large collection of samples were collected (60) from 9 common temperate forest species in July and late September over a 1 kilometer area at the Bartlett Experimental Forest in northern New Hampshire. Secondly, 15 trees were selected in a forested setting near the University of New Hampshire for more intensive phenological analysis. These samples consist of 5 white pine (Pinus strobus), 5 black oak (Quercus velutina) and 5 sugar maple (Acer saccharum). Finally, dozens of samples of white pine utilized in Forest Watch, a successful K-12 science outreach which assesses the impact of tropospheric ozone on forest health in New England, were also analyzed for this study. For all samples in this study, chlorophyll extractions were conducted to determine chlorophyll a, chlorophyll b, and total chlorophyll concentrations. Laboratory spectral analysis was performed using a GER 2600 Spectroradiometer to determine hyperspectral estimates of chlorophyll content using a Red Edge Inflection Point (REIP) approach, as well as a Transformed Chlorophyll Absorption Reflectance Index/Optimized Soil Adjusted Vegetation Index (TCARI/OSAVI) approach. These measures of chlorophyll estimation were utilized to determine whether red, green and blue spectral data from digital images taken with a Kodak C713 model camera could be used to estimate foliar chlorophyll concentrations in forest foliage. Preliminary results of this study will be presented.

In situ phytoplankton absorption, fluorescence emission, and particulate backscattering spectra determined from reflectance

NASA Technical Reports Server (NTRS)

Roesler, Collin S.; Pery, Mary Jane

1995-01-01

An inverse model was developed to extract the absortion and scattering (elastic and inelastic) properties of oceanic constituents from surface spectral reflectance measurements. In particular, phytoplankton spectral absorption coefficients, solar-stimulated chlorophyll a fluorescence spectra, and particle backscattering spectra were modeled. The model was tested on 35 reflectance spectra obtained from irradiance measurements in optically diverse ocean waters (0.07 to 25.35 mg/cu m range in surface chlorophyll a concentrations). The universality of the model was demonstrated by the accurate estimation of the spectral phytoplankton absorption coefficents over a range of 3 orders of magnitude (rho = 0.94 at 500 nm). Under most oceanic conditions (chlorophyll a less than 3 mg/cu m) the percent difference between measured and modeled phytoplankton absorption coefficents was less than 35%. Spectral variations in measured phytoplankton absorption spectra were well predicted by the inverse model. Modeled volume fluorescence was weakly correlated with measured chl a; fluorescence quantum yield varied from 0.008 to 0.09 as a function of environment and incident irradiance. Modeled particle backscattering coefficients were linearly related to total particle cross section over a twentyfold range in backscattering coefficents (rho = 0.996, n = 12).

Retrieval of chlorophyll from remote-sensing reflectance in the china seas.

PubMed

He, M X; Liu, Z S; Du, K P; Li, L P; Chen, R; Carder, K L; Lee, Z P

2000-05-20

The East China Sea is a typical case 2 water environment, where concentrations of phytoplankton pigments, suspended matter, and chromophoric dissolved organic matter (CDOM) are all higher than those in the open oceans, because of the discharge from the Yangtze River and the Yellow River. By using a hyperspectral semianalytical model, we simulated a set of remote-sensing reflectance for a variety of chlorophyll, suspended matter, and CDOM concentrations. From this simulated data set, a new algorithm for the retrieval of chlorophyll concentration from remote-sensing reflectance is proposed. For this method, we took into account the 682-nm spectral channel in addition to the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) channels. When this algorithm was applied to a field data set, the chlorophyll concentrations retrieved through the new algorithm were consistent with field measurements to within a small error of 18%, in contrast with that of 147% between the SeaWiFS ocean chlorophyll 2 algorithm and the in situ observation.

Seasonal and nonseasonal variability of satellite-derived chlorophyll and colored dissolved organic matter concentration in the California Current

NASA Astrophysics Data System (ADS)

Kahru, Mati; Mitchell, B. Greg

2001-02-01

Time series of surface chlorophyll a concentration (Chl) and colored dissolved organic matter (CDOM) derived from the Ocean Color and Temperature Sensor and Sea-Viewing Wide Field-of-View Sensor were evaluated for the California Current area using regional algorithms. Satellite data composited for 8-day periods provide the ability to describe large-scale changes in surface parameters. These changes are difficult to detect based on in situ observations alone that suffer from undersampling the large temporal and spatial variability, especially in Chl. We detected no significant bias in satellite Chl estimates compared with ship-based measurements. The variability in CDOM concentration was significantly smaller than that in Chl, both spatially and temporally. While being subject to large interannual and short-term variations, offshore waters (100-1000 km from the shore) have an annual cycle of Chl and CDOM with a maximum in winter-spring (December-March) and a minimum in late summer. For inshore waters the maximum is more likely in spring (April-May). We detect significant increase in both Chl and CDOM off central and southern California during the La Niña year of 1999. The trend of increasing Chl and CDOM from October 1996 to June 2000 is statistically significant in many areas.

Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

DTIC Science & Technology

2014-09-30

be used for habitat modeling include sea surface temperature (SST), sea surface height (SSH), chlorophyll a concentration, and primary production...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Blue and Fin Whale Habitat Modeling from Long-Term Year...predictive, year-round habitat models of the presence of calling blue and fin whales in the Southern California Bight, to facilitate Navy’s operational

Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

DTIC Science & Technology

2013-09-30

remotely sensed data to be used for habitat modeling include sea surface temperature (SST), salinity, sea surface height, and chlorophyll a concentration...National Data Buoy Center for the parts of the SCB region with HARP deployments. Figure 1. Sixteen HARP deployment locations ( black squares...throughout the Southern California Bight between 2005 and 2012 from which data are processed for habitat modeling in this study. Light grey line

Trends in Sea Ice Cover, Sea Surface Temperature, and Chlorophyll Biomass Across a Marine Distributed Biological Observatory in the Pacific Arctic Region

NASA Astrophysics Data System (ADS)

Frey, K. E.; Grebmeier, J. M.; Cooper, L. W.; Wood, C.; Panday, P. K.

2011-12-01

The northern Bering and Chukchi Seas in the Pacific Arctic Region (PAR) are among the most productive marine ecosystems in the world and act as important carbon sinks, particularly during May and June when seasonal sea ice-associated phytoplankton blooms occur throughout the region. Recent dramatic shifts in seasonal sea ice cover across the PAR should have profound consequences for this seasonal phytoplankton production as well as the intimately linked higher trophic levels. In order to investigate ecosystem responses to these observed recent shifts in sea ice cover, the development of a prototype Distributed Biological Observatory (DBO) is now underway in the PAR. The DBO is being developed as an internationally-coordinated change detection array that allows for consistent sampling and monitoring at five spatially explicit biologically productive locations across a latitudinal gradient: (1) DBO-SLP (south of St. Lawrence Island (SLI)), (2) DBO-NBS (north of SLI), (3) DBO-SCS (southern Chukchi Sea), (4) DBO-CCS (central Chukchi Sea), and (5) DBO-BCA (Barrow Canyon Arc). Standardized measurements at many of the DBO sites were made by multiple research cruises during the 2010 and 2011 pilot years, and will be expanded with the development of the DBO in coming years. In order to provide longer-term context for the changes occurring across the PAR, we utilize multi-sensor satellite data to investigate recent trends in sea ice cover, chlorophyll biomass, and sea surface temperatures for each of the five DBO sites, as well as a sixth long-term observational site in the Bering Strait. Satellite observations show that over the past three decades, trends in sea ice cover in the PAR have been heterogeneous, with significant declines in the Chukchi Sea, slight declines in the Bering Strait region, but increases in the northern Bering Sea south of SLI. Declines in the persistence of seasonal sea ice cover in the Chukchi Sea and Bering Strait region are due to both earlier sea ice breakup and later sea ice formation. Sea surface temperatures have also shown warming, where sites show significant warming particularly during August, September, and October. Satellite-derived chlorophyll-a concentrations over the past decade have shown trends seemingly in direct response to changing sea ice conditions, with increasing trends in chlorophyll-a concentrations when sea ice declines (and vice versa). In some cases, however, satellite-derived chlorophyll-a concentrations do not show expected changes with sea ice variability, indicating that limitations on biological productivity in this region are complex and spatially heterogeneous. An understanding of these spatial and temporal complexities impacting biological productivity is needed for the accurate prediction of how overall ecosystems may be altered with further expected warming sea surface temperatures and declines in sea ice cover.

Notes on a Mesodinium rubrum red tide in San Francisco Bay (California, USA)

USGS Publications Warehouse

Cloern, James E.; Cole, Brian E.; Hager, Stephen W.

1994-01-01

Discrete red patches of water were observed in South San Francisco Bay (USA) on 30 April 1993, and examination of live samples showed that this red tide was caused by surface accumulations of the pigmented ciliate Mesodinium rubrum . Vertical profiles showed strong salinity and temperature stratification in the upper 5 m, peak chlorophyll fluorescence in the upper meter, and differences in the small-scale density structure and fluorescence distribution among red patches. Events preceding this Mesodinium red tide included: (i) heavy precipitation and run-off, allowing for strong salinity stratification; (ii) a spring diatom bloom where the chlorophyll a concentration reached 50 mg m −3 ; (ii) depletions of dissolved inorganic N and Si in the photic zone; and (iv) several days of rapid warming and stabilization of the upper surface layer. These conditions may be general prerequisites for M.rubrum blooms in temperate estuaries.

An overview of remote sensing of chlorophyll fluorescence

NASA Astrophysics Data System (ADS)

Xing, Xiao-Gang; Zhao, Dong-Zhi; Liu, Yu-Guang; Yang, Jian-Hong; Xiu, Peng; Wang, Lin

2007-03-01

Besides empirical algorithms with the blue-green ratio, the algorithms based on fluorescence are also important and valid methods for retrieving chlorophyll-a concentration in the ocean waters, especially for Case II waters and the sea with algal blooming. This study reviews the history of initial cognitions, investigations and detailed approaches towards chlorophyll fluorescence, and then introduces the biological mechanism of fluorescence remote sensing and main spectral characteristics such as the positive correlation between fluorescence and chlorophyll concentration, the red shift phenomena. Meanwhile, there exist many influence factors that increase complexity of fluorescence remote sensing, such as fluorescence quantum yield, physiological status of various algae, substances with related optical property in the ocean, atmospheric absorption etc. Based on these cognitions, scientists have found two ways to calculate the amount of fluorescence detected by ocean color sensors: fluorescence line height and reflectance ratio. These two ways are currently the foundation for retrieval of chlorophyl l - a concentration in the ocean. As the in-situ measurements and synchronous satellite data are continuously being accumulated, the fluorescence remote sensing of chlorophyll-a concentration in Case II waters should be recognized more thoroughly and new algorithms could be expected.

Microdroplet fusion mass spectrometry: accelerated kinetics of acid-induced chlorophyll demetallation

PubMed Central

Lee, Jae Kyoo; Nam, Hong Gil; Zare, Richard N.

2017-01-01

Kinetics of acid-induced chlorophyll demetallation was recorded in microdroplets by fusing a stream of microdroplets containing 40 μM chlorophyll a or b dissolved in methanol with a stream of aqueous microdroplets containing 35 mM hydrochloric acid (pH = 1·46). The kinetics of the demetallation of chlorophyll in the fused microdroplets (14 ± 6 μm diameter; 84 ± 18 m s−1 velocity) was recorded by controlling the traveling distance of the fused microdroplets between the fusion region and the inlet of a mass spectrometer. The rate of acid-induced chlorophyll demetallation was about 960 ± 120 times faster in the charged microdroplets compared with that reported in bulk solution. If no voltage was applied to the sprayed microdroplets, then the acceleration factor was about 580 ± 90, suggesting that the applied voltage is not a major factor determining the acceleration. Chlorophyll a was more rapidly demetallated than chlorophyll b by a factor of ~26 in bulk solution and ~5 in charged microdroplets. The demetallation kinetics was second order in the H+ concentration, but the acceleration factor of microdroplets compared with bulk solution appeared to be unchanged in going from pH = 1·3 to 7·0. The water:methanol ratio of the fused microdroplets was varied from 7:3 to 3:7 causing an increase in the reaction rate of chlorophyll a demetallation by 20%. This observation demonstrates that the solvent composition, which has different evaporation rates, does not significantly affect the acceleration. We believe that a major portion of the acceleration can be attributed to confinement effects involving surface reactions rather than either to evaporation of solvents or to the introduction of charges to the microdroplets. PMID:29233214

Microdroplet fusion mass spectrometry: accelerated kinetics of acid-induced chlorophyll demetallation.

PubMed

Lee, Jae Kyoo; Nam, Hong Gil; Zare, Richard N

2017-01-01

Kinetics of acid-induced chlorophyll demetallation was recorded in microdroplets by fusing a stream of microdroplets containing 40 µM chlorophyll a or b dissolved in methanol with a stream of aqueous microdroplets containing 35 mM hydrochloric acid (pH = 1·46). The kinetics of the demetallation of chlorophyll in the fused microdroplets (14 ± 6 µm diameter; 84 ± 18 m s-1 velocity) was recorded by controlling the traveling distance of the fused microdroplets between the fusion region and the inlet of a mass spectrometer. The rate of acid-induced chlorophyll demetallation was about 960 ± 120 times faster in the charged microdroplets compared with that reported in bulk solution. If no voltage was applied to the sprayed microdroplets, then the acceleration factor was about 580 ± 90, suggesting that the applied voltage is not a major factor determining the acceleration. Chlorophyll a was more rapidly demetallated than chlorophyll b by a factor of ~26 in bulk solution and ~5 in charged microdroplets. The demetallation kinetics was second order in the H+ concentration, but the acceleration factor of microdroplets compared with bulk solution appeared to be unchanged in going from pH = 1·3 to 7·0. The water:methanol ratio of the fused microdroplets was varied from 7:3 to 3:7 causing an increase in the reaction rate of chlorophyll a demetallation by 20%. This observation demonstrates that the solvent composition, which has different evaporation rates, does not significantly affect the acceleration. We believe that a major portion of the acceleration can be attributed to confinement effects involving surface reactions rather than either to evaporation of solvents or to the introduction of charges to the microdroplets.

Laser Remote Sensing of Pollution on Water Surfaces

NASA Technical Reports Server (NTRS)

Bunkin, A. F.; Surovegin, Aleksander L.

1992-01-01

One of the most important problems of modern environmental science is the detection and identification of various impurities in the ocean. Sources of impurities in sea water are diverse. The most common of them are accidental transport, agricultural, and oil industry spills. Once the ecological balance is disturbed, biological processes in sea water become affected, resulting in changes in chlorophyll concentrations, water turbidity, and temperature. During the last few years, we have created new types of lidars and arranged nearly ten aircraft and shipboard expeditions. Some aircraft expeditions dealt with terrestrial investigations. Others were devoted to oceanological research, the results of which are discussed here. Emphasis is on the detection of phytoplankton chlorophyll and hydrocarbon in sea water.

[Spectral absorption properties of the water constituents in the estuary of Zhujiang River].

PubMed

Wang, Shan-shan; Wang, Yong-bo; Fu, Qing-hua; Yin, Bin; Li, Yun-mei

2014-12-01

Spectral absorption properties of the water constituents is the main factor affecting the light field under the surface of the water and the spectrum above the surface of the water. Thus, the study is useful for understanding of the water spectral property and the remote reversing of water quality parameters. Absorption properties of total suspended particles, non-algal particles, phytoplankton and CDOM were analyzed using the 30 samples collected in July 2013 in the estuary of Zhujiang River. The results indicated that: (1) the non-algal particles absorption dominated the absorption of the total suspended particles; (2) the absorption coefficient of the non-algal particles, which mainly came from the terrigenous deposits, decreased exponentially from short to long wavelength. In addition, the average value and spatial variation of the slope S(d) were higher than those in inland case- II waters; (3) the absorption coefficient of phytoplankton in 440 nm showed a better polynomial relationship with chlorophyll a concentration, while the absorption coefficient of phytoplankton in 675 nm linearly related with the chlorophyll a concentration. Moreover, the influence of accessory pigments on phytoplankton absorption coefficient mainly existed in the range of short wavelength, and Chlorophyll a was the main influencing factor for phytoplankton absorption in long wavelength. The specific absorption coefficient of phytoplankton decreased the power exponentially with the increase of the chlorophyll a concentration; (4) CDOM mainly came from the terrigenous sources and its spectral curve had an absorption shoulder between 250-290 nm. Thus, a piecewise S(g) fitting function could effectively express CDOM absorption properties, i.e., M value and S(g) value in period A (240-260 nm) showed a strong positive correlation. The M value was low, and the humic acid had a high proportion in CDOM; (5) the non-algal particles absorption dominated the total absorption in the estuary of Zhujiang River, and the contribution of the phytoplankton absorption to the total absorption was far lower than that of the non-algal particles. While the contribution of the CDOM was the lowest. The contribution of the CDOM absorption to the total absorption was relatively larger when the content of humic acid was higher.

Assessment of remotely sensed chlorophyll-a concentration in Guanabara Bay, Brazil

NASA Astrophysics Data System (ADS)

Oliveira, Eduardo N.; Fernandes, Alexandre M.; Kampel, Milton; Cordeiro, Renato C.; Brandini, Nilva; Vinzon, Susana B.; Grassi, Renata M.; Pinto, Fernando N.; Fillipo, Alessandro M.; Paranhos, Rodolfo

2016-04-01

The Guanabara Bay (GB) is an estuarine system in the metropolitan region of Rio de Janeiro (Brazil), with a surface area of ˜346 km2 threatened by anthropogenic pressure. Remote sensing can provide frequent data for studies and monitoring of water quality parameters, such as chlorophyll-a concentration (Chl-a). Different combination of Medium Resolution Imaging Spectrometer (MERIS) remote sensing reflectance band ratios were used to estimate Chl-a. Standard algorithms such as Ocean Color 3-band, Ocean Color-4 band, fluorescence line height, and maximum chlorophyll index were also tested. The MERIS Chl-a estimates were statistically compared with a dataset of in situ Chl-a (2002 to 2012). Good correlations were obtained with the use of green, red, and near-infrared bands. The best performing algorithm was based on the red (665 nm) and green (560 nm) band ratio, named "RG3" algorithm (r2=0.71, chl-a=62,565*x1.6118). The RG3 was applied to a time series of MERIS images (2003- to 2012). The GB has a high temporal and spatial variability of Chl-a, with highest values found in the wet season (October to March) and in some of the most internal regions of the estuary. Lowest concentrations are found in the central circulation channel due to the flushing of ocean water masses promoted by pumping tide.

Simulated laser fluorosensor signals from subsurface chlorophyll distributions

NASA Technical Reports Server (NTRS)

Venable, D. D.; Khatun, S.; Punjabi, A.; Poole, L.

1986-01-01

A semianalytic Monte Carlo model has been used to simulate laser fluorosensor signals returned from subsurface distributions of chlorophyll. This study assumes the only constituent of the ocean medium is the common coastal zone dinoflagellate Prorocentrum minimum. The concentration is represented by Gaussian distributions in which the location of the distribution maximum and the standard deviation are variable. Most of the qualitative features observed in the fluorescence signal for total chlorophyll concentrations up to 1.0 microg/liter can be accounted for with a simple analytic solution assuming a rectangular chlorophyll distribution function.

Identifying Distribution of Chlorophyll-a Concentration Using Landsat 8 OLI on Marine Waters Area of Cirebon

NASA Astrophysics Data System (ADS)

Buditama, Gilang; Damayanti, Astrid; Giok Pin, Tjiong

2017-12-01

Phytoplankton is a microscopic plant that has a function to produces oxygen and organic substances. It also plays a role as a main producer in the food chain of a marine ecosystem. Chlorophyll-a is a colour pigment most common in phytoplankton species, so that the concentration level of chlorophyll-a can be used as an indicator of the abundance of phytoplankton cells, and as a reference for predicting organic potency in the aquatic area. This research discusses about the spatial and temporal distribution of chlorophyll-a and its correlation with salinity and total suspended solid (TSS), in the seawaters of Cirebon, West Java. The goal of this research is to be a source of information for fishermen, and other stakeholders whose related subjects in the field of marine and fisheries to predict fertile water regions and can also be used as an indicator in discovering potential areas to catch pelagic fish in Cirebon seawaters. Chlorophyll-a concentration, salinity, and TSS are identified using remote sensing data such as Landsat-8 OLI multi temporal images according to dry and wet month parameters in the 2014-2015. The results of the processed image are then validated between in-situ measurements in the field and remote sensing imagery at the same time. This research utilizes descriptive analysis, and statistics with spatial approach. The results of the research show that temporally, chlorophyll-a levels have a tendency to be higher in wet months compared to dry months, while chlorophyll-a is higher in areas near the coastline compared to open sea areas. The distribution of chlorophyll-a concentration is affected by salinity and TSS distribution, where salinity has the negative relationship and TSS has the positive relationship with chlorophyll-a distribution.

Quantification of Plant Chlorophyll Content Using Google Glass

PubMed Central

Cortazar, Bingen; Koydemir, Hatice Ceylan; Tseng, Derek; Feng, Steve; Ozcan, Aydogan

2015-01-01

Measuring plant chlorophyll concentration is a well-known and commonly used method in agriculture and environmental applications for monitoring plant health, which also correlates with many other plant parameters including, e.g., carotenoids, nitrogen, maximum green fluorescence, etc. Direct chlorophyll measurement using chemical extraction is destructive, complex and time-consuming, which has led to the development of mobile optical readers, providing non-destructive but at the same time relatively expensive tools for evaluation of plant chlorophyll levels. Here we demonstrate accurate measurement of chlorophyll concentration in plant leaves using Google Glass and a custom-developed software application together with a cost-effective leaf holder and multi-spectral illuminator device. Two images, taken using Google Glass, of a leaf placed in our portable illuminator device under red and white (i.e., broadband) light-emitting-diode (LED) illumination are uploaded to our servers for remote digital processing and chlorophyll quantification, with results returned to the user in less than 10 seconds. Intensity measurements extracted from the uploaded images are mapped against gold-standard colorimetric measurements made through a commercially available reader to generate calibration curves for plant leaf chlorophyll concentration. Using five plant species to calibrate our system, we demonstrate that our approach can accurately and rapidly estimate chlorophyll concentration of fifteen different plant species under both indoor and outdoor lighting conditions. This Google Glass based chlorophyll measurement platform can display the results in spatiotemporal and tabular forms and would be highly useful for monitoring of plant health in environmental and agriculture related applications, including e.g., urban plant monitoring, indirect measurements of the effects of climate change, and as an early indicator for water, soil, and air quality degradation. PMID:25669673

Quantification of plant chlorophyll content using Google Glass.

PubMed

Cortazar, Bingen; Koydemir, Hatice Ceylan; Tseng, Derek; Feng, Steve; Ozcan, Aydogan

2015-04-07

Measuring plant chlorophyll concentration is a well-known and commonly used method in agriculture and environmental applications for monitoring plant health, which also correlates with many other plant parameters including, e.g., carotenoids, nitrogen, maximum green fluorescence, etc. Direct chlorophyll measurement using chemical extraction is destructive, complex and time-consuming, which has led to the development of mobile optical readers, providing non-destructive but at the same time relatively expensive tools for evaluation of plant chlorophyll levels. Here we demonstrate accurate measurement of chlorophyll concentration in plant leaves using Google Glass and a custom-developed software application together with a cost-effective leaf holder and multi-spectral illuminator device. Two images, taken using Google Glass, of a leaf placed in our portable illuminator device under red and white (i.e., broadband) light-emitting-diode (LED) illumination are uploaded to our servers for remote digital processing and chlorophyll quantification, with results returned to the user in less than 10 seconds. Intensity measurements extracted from the uploaded images are mapped against gold-standard colorimetric measurements made through a commercially available reader to generate calibration curves for plant leaf chlorophyll concentration. Using five plant species to calibrate our system, we demonstrate that our approach can accurately and rapidly estimate chlorophyll concentration of fifteen different plant species under both indoor and outdoor lighting conditions. This Google Glass based chlorophyll measurement platform can display the results in spatiotemporal and tabular forms and would be highly useful for monitoring of plant health in environmental and agriculture related applications, including e.g., urban plant monitoring, indirect measurements of the effects of climate change, and as an early indicator for water, soil, and air quality degradation.

Measuring leaf chlorophyll concentration from its color: A way in monitoring environment change to plantations

NASA Astrophysics Data System (ADS)

Shibghatallah, Muhammad Abdul Hakim; Khotimah, Siti Nurul; Suhandono, Sony; Viridi, Sparisoma; Kesuma, Teja

2013-09-01

Leaf colors of a plant can be used to identify stress level due to its adaptation to environmental change. For most leaves green-related colors are sourced from chlorophyll a and b. Chlorophyll concentration is normally measured using a spectrophotometer in laboratory. In some remote observation places, it is impossible to collect the leaves, preserve them, and bring them to laboratory to measure their chlorophyll content. Based on this need, measurement of chlorophyll content is observed through its color. Using CIE chromaticity diagram leaf_color information in RGB is transformed into wavelength (in nm). Paddy seed with variety name IR-64 is used in observation during its vegetation stage t (age of 0-10 days). Light exposure time τ is chosen as environmental change, which normally should be about 12 hours/day, is varied (0-12 hours/day). Each day sample from different exposure time is taken, its color is recorded using HP Deskjet 1050 scanner with 1200 dpi, and its chlorophyll content is obtained from absorption spectrum measured using Campspec M501 Single Beam UV/Vis Spectrophotometer after it is rinsed in 85 % acetone solution and the information from the spectrum is calculated using Arnon method. It has been observed that average wavelength of leaf color λavg is decreased from 570.55 nm to 566.01 nm as is measured for t = 1 - 10 days with τ = 9 hours/day, but chlorophyll concentration C is increased from 0.015 g/l to 3.250 g/l and from 0.000 g/l to 0.774 g/l for chlorophyll a and b, respectively. Other value of τ gives similar results. Based on these results an empirical relation between concentration of chlorophyll a Cc-a and its wavelength λavg can be formulated.

Surface disturbance of cryptobiotic soil crusts: nitrogenase activity, chlorophyll content, and chlorophyll degradation

USGS Publications Warehouse

Belnap, Jayne; Harper, Kimball T.; Warren, Steven D.

1994-01-01

Cryptobiotic soil crusts are an important component of semiarid and arid ecosystems. An important role of these crusts is the contribution of fixed nitrogen to cold‐desert ecosystems. This study examines the residual effects of various intensities and combinations of different surface disturbances (raking, scalping, and tracked vehicles) on nitrogenase activity, chlorophyll content, and chlorophyll degradation in these soil crusts. Nine months after disturbance chlorophyll content of disturbed soils was not statistically different from undisturbed controls, except in the scalped treatments, indicating recovery of this characteristic is fairly quick unless surface material is removed. Differences in chlorophyll degradation among treatments were not statistically significant. However, nitrogenase activity in all treatments showed tremendous reductions, ranging from 77–97%, when compared to the control, indicating this characteristic is slow to recover. Consequently, assessment of crustal recovery from disturbance must include not only visual and biomass characteristics but other physiological measurements as well. Areas dominated by these crusts should be managed conservatively until the implications of crustal disturbance is better understood.

Evaluation of Organic Proxies for Quantifying Past Primary Productivity

NASA Astrophysics Data System (ADS)

Raja, M.; Rosell-Melé, A.; Galbraith, E.

2017-12-01

Ocean primary productivity is a key element of the marine carbon cycle. However, its quantitative reconstruction in the past relies on the use of biogeochemical models as the available proxy approaches are qualitative at best. Here, we present an approach that evaluates the use of phytoplanktonic biomarkers (i.e. chlorins and alkenones) as quantitative proxies to reconstruct past changes in marine productivity. We compare biomarkers contents in a global suite of core-top sediments to sea-surface chlorophyll-a abundance estimated by satellites over the last 20 years, and the results are compared to total organic carbon (TOC). We also assess satellite data and detect satellite limitations and biases due to the complexity of optical properties and the actual defined algorithms. Our findings show that sedimentary chlorins can be used to track total sea-surface chlorophyll-a abundance as an indicator for past primary productivity. However, degradation processes restrict the application of this proxy to concentrations below a threshold value (1µg/g). Below this threshold, chlorins are a useful tool to identify reducing conditions when used as part of a multiproxy approach to assess redox sedimentary conditions (e.g. using Re, U). This is based on the link between anoxic/disoxic conditions and the flux of organic matter from the sea-surface to the sediments. We also show that TOC is less accurate than chlorins for estimating sea-surface chlorophyll-a due to the contribution of terrigenous organic matter, and the different degradation pathways of all organic compounds that TOC includes. Alkenones concentration also relates to primary productivity, but they are constrained by different processes in different regions. In conclusion, as lons as specific constraints are taken into account, our study evaluates the use of chlorins and alkenones as quantitative proxies of past primary productivity, with more accuracy than by using TOC.

Planktic foraminiferal production stimulated by chlorophyll redistribution and entrainment of nutrients

NASA Astrophysics Data System (ADS)

Schiebel, Ralf; Waniek, Joanna; Bork, Matthias; Hemleben, Christoph

2001-03-01

During September and October 1996 planktic foraminifers and pteropods were sampled from the upper 2500 m of the water column in the BIOTRANS area (47°N, 20°W), eastern North Atlantic, as part of the JGOFS program. Hydrography, chlorophyll fluorescence, and nutrient content were recorded at high spatial and temporal resolution providing detailed information about the transition time between summer and fall. At the beginning of the cruise a shallow pycnocline was present and oligotrophic conditions prevailed. Over the course of the cruise, the mixed layer depth increased and surface water temperature decreased by 1.5°C. Both chlorophyll- a dispersed in the upper 50 m by vertical mixing and chlorophyll- a concentrations at the sea surface increased. The nitracline shoaled and nutrient enriched waters were entrained into the mixed layer. Planktic foraminifers and pteropods closely reflected the changes in the hydrography by increased growth rates and changes in species composition. Three main groups of planktic foraminiferal species were recognized: (1) a temperate and low-productivity group dominated by Neogloboquadrina incompta characterized the shallow mixed layer depths. (2) A temperate and high-productivity group dominated by Globigerina bulloides characterized the period with wind-induced dispersal of chlorophyll- a and entrainment of nutrient-enriched waters. (3) A warm water group containing Globigerinoides sacculifer, Orbulina universa, Globigerinoides ruber (white), and Globigerinella siphonifera was most common during the first days of sampling. Synchronous with the hydrographic change from summer to fall, planktic foraminiferal and pteropod growth was stimulated by redistribution of chlorophyll- a and entrainment of nutrient-enriched waters into the mixed layer. In addition, the seasonal change in the eastern North Atlantic resulted in a transition of the epipelagic faunal composition and an increased calcareous particle flux, which could be used to trace seasonality in fossil assemblages and allow for better paleoceanographic interpretation of the boreal Atlantic.

Seasonal Variation of Phytoplankton and Primary Production in the Thames River, Southeastern Connecticut

NASA Astrophysics Data System (ADS)

Wainright, S. C.

2016-02-01

A year-long study was performed to investigate seasonal changes in the phytoplankton biomass and primary production in the Thames River, a salt wedge estuary that empties into Long Island Sound in southeastern CT. Chlorophyll measurements were made on discrete filtered samples collected above and below the 1-3 m deep pycnocline at a 5-meter deep station. Surface chlorophyll concentrations, primarily from diatoms, averaged approx. 2 mg m-3, with maxima (up to 10 mg m-3) during summer months (Jun to Aug) and minima during October through March (as low as 0.3 mg m-3). The lower water layer had nearly the same annual average but a smaller range (0.7-3.3 mg m-3) and a winter/spring bloom (Jan-Apr) that was not seen in surface water. During most of the winter, chlorophyll concentrations were higher in the lower layer. Primary production, as measured by 13C uptake in bottle incubations, averaged 67 mgC m-3 h-1 in surface water [range 0.1 (Jan 2012) to 800 mgC m-3 h-1 (Aug 2011)], and 3 mgC m-3 h-1 [range 0.04 (Jan 2012) to 17 mgC m-3 h-1 (Aug 2011)] in the lower layer. On most occasions, deep water incubated near the surface had a higher primary production rate than surface water incubated at the surface; apparently the light-limited phytoplankton in the lower layer were released from light-limitation during these incubations. During the study period there were over a dozen heavy wind or heavy rain events, including Hurricane Irene in August and a freak Nor'easter snow storm in October 2011. Hurricane Irene was associated with a large decline in phytoplankton biomass and primary production. With significant storms as frequent as the rate of sampling, it is difficult to separate a "storm effect" from a background seasonal pattern. The study reveals that phytoplankton, especially those in the lower layer, are light-limited in the Thames River estuary, and that the effects of significant storm events are superimposed on significant seasonal variation.

Biomass assessment of microbial surface communities by means of hyperspectral remote sensing data.

PubMed

Rodríguez-Caballero, Emilio; Paul, Max; Tamm, Alexandra; Caesar, Jennifer; Büdel, Burkhard; Escribano, Paula; Hill, Joachim; Weber, Bettina

2017-05-15

Dryland vegetation developed morphological and physiological strategies to cope with drought. However, as aridity increases, vascular plant coverage gets sparse and microbially-dominated surface communities (MSC), comprising cyanobacteria, algae, lichens and bryophytes together with heterotropic bacteria, archaea and fungi, gain relevance. Nevertheless, the relevance of MSC net primary productivity has only rarely been considered in ecosystem scale studies, and detailed information on their contribution to the total photosynthetic biomass reservoir is largely missing. In this study, we mapped the spatial distribution of two different MSC (biological soil crusts and quartz fields hosting hypolithic crusts) at two different sites within the South African Succulent Karoo (Soebatsfontein and Knersvlakte). Then we characterized both types of MSC in terms of chlorophyll content, and combining these data with the biocrust and quartz field maps, we estimated total biomass values of MSCs and their spatial patterns within the two different ecosystems. Our results revealed that MSC are important vegetation components of the South African Karoo biome, revealing clear differences between the two sites. At Soebatsfontein, MSC occurred as biological soil crusts (biocrusts), which covered about one third of the landscape reaching an overall biomass value of ~480gha -1 of chlorophyll a+b at the landscape scale. In the Knersvlakte, which is characterized by harsher environmental conditions (i.e. higher solar radiation and potential evapotranspiration), MSC occurred as biocrusts, but also formed hypolithic crusts growing on the lower soil-immersed parts of translucent quartz pebbles. Whereas chlorophyll concentrations of biocrusts and hypolithic crusts where insignificantly lower in the Knersvlakte, the overall MSC biomass reservoir was by far larger with ~780gha -1 of chlorophyll a+b. Thus, the complementary microbially-dominated surface communities promoted biomass formation within the environmentally harsh Knersvlakte ecosystem. Copyright © 2017 Elsevier B.V. All rights reserved.

How important are coastal fronts to albacore tuna (Thunnus alalunga) habitat in the Northeast Pacific Ocean?

NASA Astrophysics Data System (ADS)

Nieto, Karen; Xu, Yi; Teo, Steven L. H.; McClatchie, Sam; Holmes, John

2017-01-01

We used satellite sea surface temperature (SST) data to characterize coastal fronts and then tested the effects of the fronts and other environmental variables on the distribution of the albacore tuna (Thunnus alalunga) catches in the coastal areas (from the coast to 200 nm offshore) of the Northeast Pacific Ocean. A boosted regression tree (BRT) model was used to explain the spatial and temporal patterns in albacore tuna catch per unit effort (CPUE) (1988-2011), using frontal features (distance to the front and temperature gradient), and other environmental variables like SST, surface chlorophyll concentration (chlorophyll), and geostrophic currents as explanatory variables. Based on over two decades of high-resolution data, the modeled results confirmed previous findings that albacore CPUE distribution is strongly influenced by SST and chlorophyll at fishing locations, and the distance of fronts from the coast (DFRONT-COAST), albeit with substantial seasonal and interannual variation. Albacore CPUEs were higher near warm, low chlorophyll oceanic waters, and near SST fronts. We performed sequential leave-one-year-out cross-validations for all years and found that the relationships in the BRT models were robust for the entire study period. Spatial distributions of model-predicted albacore CPUE were similar to observations, but the model was unable to predict very high CPUEs in some areas. These results help to explain previously observed variability in albacore CPUE and will likely help improve international fisheries management in the face of environmental changes.

Optical properties of intact leaves for estimating chlorophyll concentration

NASA Technical Reports Server (NTRS)

Carter, Gregory A.; Spiering, Bruce A.

2002-01-01

Changes in leaf chlorophyll content can serve as relative indicators of plant vigor and environmental quality. This study identified reflectance, transmittance, and absorptance wavebands and band ratios within the 400- to 850-nm range for intact leaves that could be used to estimate extracted leaf chlorophyll per unit leaf area (areal concentration) with minimal error. Leaf optical properties along with chlorophyll a, b, and a + b concentrations were measured for the planar-leaved sweetgum (Liquidambar styraciflua L.), red maple (Acer rubrum L.), wild grape (Vitis rotundifolia Michx.), and switchcane [Arundinaria gigantea (Walter) Muhl.], and for needles of longleaf pine (Pinus palustris Miller). Generally, reflectance, transmittance, and absorptance corresponded most precisely with chlorophyll concentrations at wavelengths near 700 nm, although regressions were also strong in the 550- to 625-nm range. A power function was superior to a simple linear function in yielding low standard deviations of the estimate (s). When data were combined among the planar-leaved species, s values were low at approximately 50 mumol/m2 out of a 940 mumol/m2 range in chlorophyll a + b at best-fit wavelengths of 707 to 709 nm. Minimal s values for chlorophyll a + b ranged from 32 to 62 mumol/m2 across species when band ratios having numerator wavelengths of 693 to 720 nm were used with the application of a power function. Optimal denominator wavelengths for the band ratios were 850 nm for reflectance and transmittance and 400 nm for absorptance. This information can be applied in designing field portable chlorophyll meters and in the landscape-scale remote sensing of plant responses to the environment.

Mapping of chlorophyll a distributions in coastal zones

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1978-01-01

It is pointed out that chlorophyll a is an important environmental parameter for monitoring water quality, nutrient loads, and pollution effects in coastal zones. High chlorophyll a concentrations occur in areas which have high nutrient inflows from sources such as sewage treatment plants and industrial wastes. Low chlorophyll a concentrations may be due to the addition of toxic substances from industrial wastes or other sources. Remote sensing provides an opportunity to assess distributions of water quality parameters, such as chlorophyll a. A description is presented of the chlorophyll a analysis and a quantitative mapping of the James River, Virginia. An approach considered by Johnson (1977) was used in the analysis. An application of the multiple regression analysis technique to a data set collected over the New York Bight, an environmentally different area of the coastal zone, is also discussed.

Bio-optical properties of Arctic drift ice and surface waters north of Svalbard from winter to spring

NASA Astrophysics Data System (ADS)

Kowalczuk, Piotr; Meler, Justyna; Kauko, Hanna M.; Pavlov, Alexey K.; Zabłocka, Monika; Peeken, Ilka; Dybwad, Christine; Castellani, Giulia; Granskog, Mats A.

2017-06-01

We have quantified absorption by CDOM, aCDOM(λ), particulate matter, ap(λ), algal pigments, aph(λ), and detrital material, aNAP(λ), coincident with chlorophyll a in sea ice and surface waters in winter and spring 2015 in the Arctic Ocean north of Svalbard. The aCDOM(λ) was low in contrast to other regions of the Arctic Ocean, while ap(λ) has the largest contribution to absorption variability in sea ice and surface waters. ap(443) was 1.4-2.8 times and 1.3-1.8 times higher than aCDOM(443) in surface water and sea ice, respectively. aph(λ) contributed 90% and 81% to ap(λ), in open leads and under-ice waters column, and much less (53%-74%) in sea ice, respectively. Both aCDOM(λ) and ap(λ) followed closely the vertical distribution of chlorophyll a in sea ice and the water column. We observed a tenfold increase of the chlorophyll a concentration and nearly twofold increase in absorption at 443 nm in sea ice from winter to spring. The aCDOM(λ) dominated the absorption budget in the UV both in sea ice and surface waters. In the visible range, absorption was dominated by aph(λ), which contributed more than 50% and aCDOM(λ), which contributed 43% to total absorption in water column. Detrital absorption contributed significantly (33%) only in surface ice layer. Algae dynamics explained more than 90% variability in ap(λ) and aph(λ) in water column, but less than 70% in the sea ice. This study presents detailed absorption budget that is relevant for modeling of radiative transfer and primary production.

Record of El Niño in planktonic foraminiferal assemblages from the Gulf of Tehuantepec, Mexico (Eastern Tropical Pacific)

NASA Astrophysics Data System (ADS)

Machain-Castillo, M. L.; Nava-Fernandez, X. A.; Thunell, R.; Tappa, E.

2013-05-01

The planktonic foraminiferal assemblages from two sediment traps deployed in the Gulf of Tehuantepec, Mexico (Eastern Tropical Pacific) during a five year period (2006 to 2010) were recorded. The species abundance data were subjected to a Q-mode factor analysis that depicts alternating associations of planktonic foraminifera, generally related to seasonally varying oceanographic conditions. During winter-spring season, the oceanography of the Gulf of Tehuantepec is driven by strong northern winds that cross the Isthmus of Tehuantepec and produce intense upwelling in the gulf. This upwelling of cold, nutrient-rich waters induces high biological productivity and the dominance of the planktonic foraminiferal species Globigerina bulloides. Summer-fall oceanographic conditions are dominated by the northward flow of the Costa Rica Coastal Current and a stratified water column. Chlorophyll-a concentrations are much lower than during the upwelling season and the Globorotalia menardii assemblage is characteristic. The above pattern was recorded for most of the study period, except during ENSO conditions in winter 2007 and summer-fall of 2009. From mid-January to early March 2007, the assemblage was dominated by G. menardii instead of the typical G. bulloides. This period had the highest sea surface temperatures and lowest surface chlorophyll-a values recorded for the entire five year study period. During the similar time period of ENSO 2010, the G. bulloides assemblage shows the highest scores in the factor analysis, although the G. menardii assemblage also has somewhat high scores. Temperature is slightly lower and chlorophyll-a values are slightly higher than during 2007, suggesting the conditions were not strong enough to induce a change in faunal dominance. During ENSO 2009 (July 8th to November 12th), the summer-fall dominant assemblage of Globorotalia menardii was replaced by the Globigerinoides ruber - Globigerinita glutinata assemblage, associated to the summer-fall highest average temperatures and lowest chlorophyll-a concentrations at the studied site.

Distribution of Bioactive Trace Metals (Fe, Co, Ni, Cu and Zn) in the semiarid Kuwait Bay, stressed by natural and anthropogenic processes

NASA Astrophysics Data System (ADS)

Al-Said, T. F.; Pokavanich, T.; Al-Hashem, A.; Kedila, R.

2016-02-01

Kuwait is in the northwestern part of the Arabian Gulf and receives flow from Shatt Al-Arab River as the main fresh water input to the Gulf. Kuwait's waters can be described as eutrophic, euphotic, and highly saline waters. The main objective of the study is to assess spatial and temporal distribution of Cu, Co, Zn, Fe and Ni, nutrients such as nitrate and phosphate, chlorophyll-a and physical variables along transects in Kuwait's Waters. No systematic research on bioactive metals has been studied in the region. Concentration of trace metal in the shallow Kuwait Bay was relatively high and decreased towards the southern water. This is attributed to higher sewage input, domestic and industrial effluents, dust storms and human activities. Cu, Ni, Fe, Zn and Co levels were measured using proven tested methodology i.e., Adsorptive Cathodic Stripping Voltammetry (Ad-CSV) and Flow Injection Analyzer (FIA). Surface seawater samples were collected from 26 stations using clean polyethylene sampling devices from four transects during two seasons in 2015. Average concentrations of Copper, Nickel, Cobalt, Zinc and chlorophyll-a corresponded to 14.99, 22.32, 0.74, 14.56 nM and 3.05µg/L during June 2015. These values indicated lower concentrations compared to previously published values from Kuwait's waters: Cu 48.52, Ni 26.12, Co 4.69, Zn 93.86 nM. Two transects conducted during summer 2015 showed positive relationship between metals (Cu, Co and Ni) and chlorophyll. Strong and apparent correlation was observed between cobalt and chlorophyll-a in Kuwait Bay indicating that these micronutrient are abundant and higher than phytoplankton essential requirements. Recent measured Fe concentration 7.95nM in Kuwait Bay was comparable to values found in similar coastal water. Latest results obtained during the transactional surveys and processes involved in Kuwait's waters will be shown and discussed during the presentation.

Assessing the link between chlorophyll concentration and absorption line height at 676 nm over a broad range of water types.

PubMed

Nardelli, Schuyler C; Twardowski, Michael S

2016-10-31

The relationship between absorption at 676 nm normalized to chlorophyll-a, i.e., specific absorption aph*(676), and various optical and environmental properties is examined in extensive data sets from Case I and Case II waters found globally to assess drivers of variability such as pigment packaging. A better understanding of this variability could lead to more accurate estimates of chlorophyll concentrations from in situ optical measurements that may be made autonomously. Values of aph*(676) ranged from 0.00006 to 0.0944 m²/mg Chl a across all sites studied, but converged on median and mean values (n = 563) of 0.0108 and 0.0139 m²/mg Chl a respectively, with no apparent relationship with various optical properties, latitude, coastal or open ocean environment, depth, temperature, salinity, photoadaptation, ecosystem health, or albedo. Relative consistency in aph* across such diverse water types and the full range in chlorophyll concentration suggests a single aph* may be used to estimate chlorophyll concentration from absorption measurements with better accuracy than currently thought.

Oceanic Lidar

NASA Technical Reports Server (NTRS)

Carder, K. L. (Editor)

1981-01-01

Instrument concepts which measure ocean temperature, chlorophyll, sediment and Gelbstoffe concentrations in three dimensions on a quantitative, quasi-synoptic basis were considered. Coastal zone color scanner chlorophyll imagery, laser stimulated Raman temperaure and fluorescence spectroscopy, existing airborne Lidar and laser fluorosensing instruments, and their accuracies in quantifying concentrations of chlorophyll, suspended sediments and Gelbstoffe are presented. Lidar applications to phytoplankton dynamics and photochemistry, Lidar radiative transfer and signal interpretation, and Lidar technology are discussed.

Effects of Sucrose and Kinetin on Growth and Chlorophyll Synthesis in Tobacco Tissue Cultures 1

PubMed Central

Kaul, K.; Sabharwal, P. S.

1971-01-01

Investigations were carried out on the effects of various combinations of sucrose and kinetin concentrations on growth and chlorophyll production in a green and a nongreen clone of pith callus of Nicotiana tabacum L. It was found that 2 milligrams per liter or higher amounts of kinetin induced greening in the nongreen tissue. The observations suggested that growth of the callus and synthesis of chlorophyll and soluble protein are controlled by relative concentrations of sucrose and kinetin in the medium. Kinetin was found to be inhibitory for chlorophyll synthesis in the green callus. PMID:16657686

Best of both worlds: simultaneous high-light and shade-tolerance adaptations within individual leaves of the living stone Lithops aucampiae.

PubMed

Field, Katie J; George, Rachel; Fearn, Brian; Quick, W Paul; Davey, Matthew P

2013-01-01

"Living stones" (Lithops spp.) display some of the most extreme morphological and physiological adaptations in the plant kingdom to tolerate the xeric environments in which they grow. The physiological mechanisms that optimise the photosynthetic processes of Lithops spp. while minimising transpirational water loss in both above- and below-ground tissues remain unclear. Our experiments have shown unique simultaneous high-light and shade-tolerant adaptations within individual leaves of Lithops aucampiae. Leaf windows on the upper surfaces of the plant allow sunlight to penetrate to photosynthetic tissues within while sunlight-blocking flavonoid accumulation limits incoming solar radiation and aids screening of harmful UV radiation. Increased concentration of chlorophyll a and greater chlorophyll a:b in above-ground regions of leaves enable maximum photosynthetic use of incoming light, while inverted conical epidermal cells, increased chlorophyll b, and reduced chlorophyll a:b ensure maximum absorption and use of low light levels within the below-ground region of the leaf. High NPQ capacity affords physiological flexibility under variable natural light conditions. Our findings demonstrate unprecedented physiological flexibility in a xerophyte and further our understanding of plant responses and adaptations to extreme environments.

Carbon: Chlorophyll Ratios and Net Primary Productivity of Subarctic Pacific Surface Waters Derived From Autonomous Shipboard Sensors

NASA Astrophysics Data System (ADS)

Burt, William J.; Westberry, Toby K.; Behrenfeld, Michael J.; Zeng, Chen; Izett, Robert W.; Tortell, Philippe D.

2018-02-01

We present optically derived estimates of phytoplankton carbon (Cphyto) and chlorophyll a concentration (Chl) across a wide range of productivity and hydrographic regimes in the Subarctic Pacific Ocean. Our high-frequency measurements capture changes in Cphyto and Chl across regional gradients in macronutrient and micronutrient limitations and submesoscale hydrographic frontal zones. Throughout the majority of our survey region, carbon to chlorophyll ratios (Cphyto:Chl) ranged between 50 and 100. Lower values (10-20) were constrained to the highly productive coastal upwelling system along Vancouver Island, whereas higher estimated values (>200) were found directly off the southern British Columbia continental shelf. Further offshore, Cphyto:Chl was less variable, ranging from 50 to 80 in high nutrient low Chl waters in June and from 80 to 120 in the Gulf of Alaska in July. Much of the variability in Cphyto:Chl throughout the study region could be explained by mixed-layer light levels (i.e., photoacclimation), with additional variability attributed to nutrient-controlled changes in phytoplankton growth rates in some regions. Elevated Cphyto:Chl ratios resulting from apparent nutrient stress were found in areas of low macronutrient concentrations. In contrast, iron-limited waters exhibited Cphyto:Chl ratios lower than predicted from the photoacclimation model. Applying the carbon-based production model, we derived Cphyto and Chl-based estimates of net primary productivity, which showed good coherence with independent 14C uptake measurements. Our results highlight the utility of ship-board optical data to examine phytoplankton physiological ecology and productivity in surface marine waters.

Vegetation chlorophyll estimates in the Amazon from multi-angle MODIS observations and canopy reflectance model

NASA Astrophysics Data System (ADS)

Hilker, Thomas; Galvão, Lênio Soares; Aragão, Luiz E. O. C.; de Moura, Yhasmin M.; do Amaral, Cibele H.; Lyapustin, Alexei I.; Wu, Jin; Albert, Loren P.; Ferreira, Marciel José; Anderson, Liana O.; dos Santos, Victor A. H. F.; Prohaska, Neill; Tribuzy, Edgard; Barbosa Ceron, João Vitor; Saleska, Scott R.; Wang, Yujie; de Carvalho Gonçalves, José Francisco; de Oliveira Junior, Raimundo Cosme; Cardoso Rodrigues, João Victor Figueiredo; Garcia, Maquelle Neves

2017-06-01

As a preparatory study for future hyperspectral missions that can measure canopy chemistry, we introduce a novel approach to investigate whether multi-angle Moderate Resolution Imaging Spectroradiometer (MODIS) data can be used to generate a preliminary database with long-term estimates of chlorophyll. MODIS monthly chlorophyll estimates between 2000 and 2015, derived from a fully coupled canopy reflectance model (ProSAIL), were inspected for consistency with eddy covariance fluxes, tower-based hyperspectral images and chlorophyll measurements. MODIS chlorophyll estimates from the inverse model showed strong seasonal variations across two flux-tower sites in central and eastern Amazon. Marked increases in chlorophyll concentrations were observed during the early dry season. Remotely sensed chlorophyll concentrations were correlated to field measurements (r2 = 0.73 and r2 = 0.98) but the data deviated from the 1:1 line with root mean square errors (RMSE) ranging from 0.355 μg cm-2 (Tapajós tower) to 0.470 μg cm-2 (Manaus tower). The chlorophyll estimates were consistent with flux tower measurements of photosynthetically active radiation (PAR) and net ecosystem productivity (NEP). We also applied ProSAIL to mono-angle hyperspectral observations from a camera installed on a tower to scale modeled chlorophyll pigments to MODIS observations (r2 = 0.73). Chlorophyll pigment concentrations (ChlA+B) were correlated to changes in the amount of young and mature leaf area per month (0.59 ≤ r2 ≤ 0.64). Increases in MODIS observed ChlA+B were preceded by increased PAR during the dry season (0.61 ≤ r2 ≤ 0.62) and followed by changes in net carbon uptake. We conclude that, at these two sites, changes in LAI, coupled with changes in leaf chlorophyll, are comparable with seasonality of plant productivity. Our results allowed the preliminary development of a 15-year time series of chlorophyll estimates over the Amazon to support canopy chemistry studies using future hyperspectral sensors.

Chemotaxonomic phytoplankton patterns on the eastern boundary of the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Barlow, R.; Gibberd, M.-J.; Lamont, T.; Aiken, J.; Holligan, P.

2016-05-01

Surface pigment data from a transect along the eastern boundary of the Atlantic Ocean was analysed using CHEMTAX to yield more detailed information on the composition of phytoplankton communities. Total chlorophyll a concentrations varied from 0.03 mg m-3 in a northern oligotrophic region to 30.3 mg m-3 in the Benguela ecosystem. Diatoms dominated the Benguela, while both diatoms and haptophytes were the major groups in the Canary ecosystem and the temperate NE Atlantic. Prochlorococcus was the most prominent group in the southern oligotrophic region (15.5°S-15°N) although haptophytes were also a significant component of the population. In contrast, haptophytes dominated the northern oligotrophic region (21°-40°N). Photo-pigment indices indicated that chlorophyll b was mainly associated with prasinophytes and chlorophyll c with diatoms. Elevated photosynthetic carotenoids were due to increased proportions of haptophytes, but also linked with diatoms and dinoflagellates. Photoprotective carotenoids were more prominently associated with Prochlorococcus and to a lesser extent to Synechococcus.

The use of ERTS-1 to more fully utilize and apply marine station data to the study and productivity along the eastern shelf waters of the United States

NASA Technical Reports Server (NTRS)

Marshall, H. G. (Principal Investigator); Bowker, D. E.; Witte, W. G.

1976-01-01

The author has identified the following significant results. Sea truth data were obtained during two ERTS overpasses in waters near the entrance of the Chesapeake Bay. Correlations were made between total phytoplankton and chlorophyll values in these waters to radiance detected by ERTS in an effort to map areas of similar productivity levels. Band 4 radiance had the highest correlation to all parameters with bands 5 and 6 showing decreasing correlations in each case. The radiance values were apparently influenced by one or more factors, most likely including the sediment content of the water. Data have shown that ERTS MSS is not suitable for monitoring chlorophyll in near-shore waters where sediment loads are high. It is suggested that in more seaward or pelagic locations, that ERTS MSS would be more efficient in monitoring surface chlorophyll values and establishing direct relationships to phytoplankton concentrations.

Virginia Water Resources: Utilizing NASA Earth Observations to Monitor the Extent of Harmful Algal Blooms in Virginia Rivers

NASA Astrophysics Data System (ADS)

Lubkin, S. H.; Morgan, C.

2015-12-01

Harmful algal bloom species have had an increasing ecological impact on the Chesapeake Bay Watershed where they disrupt water chemistry, kill fish and cause human illness. In Virginia, scientists from Virginia Institute of Marine Science and Old Dominion University monitor HABs and their effect on water quality; however, these groups lack a method to monitor HABs in real time. This limits the ability to document associated water quality conditions and predict future blooms. Band reflectance values from Landsat 8 Surface Reflectance data (USGS Earth Explorer) and MODIS Chlorophyll imagery (NOAA CoastWatch) were cross calibrated to create a regression model that calculated concentrations of chlorophyll. Calculations were verified with in situ measurements from the Virginia Estuarine and Coastal Observing System. Imagery produced with the Chlorophyll-A calculation model will allow VIMS and ODU scientists to assess the timing, magnitude, duration and frequency of HABs in Virginia's Chesapeake watershed and to predict the environmental and water quality conditions that favor bloom development.

Use of a SPAD-502 meter to measure leaf chlorophyll concentration in Arabidopsis thaliana.

PubMed

Ling, Qihua; Huang, Weihua; Jarvis, Paul

2011-02-01

The SPAD-502 meter is a hand-held device that is widely used for the rapid, accurate and non-destructive measurement of leaf chlorophyll concentrations. It has been employed extensively in both research and agricultural applications, with a range of different plant species. However, its utility has not been fully exploited in relation to the most intensively studied model organism for plant science research, Arabidopsis thaliana. Measurements with the SPAD-502 meter produce relative SPAD meter values that are proportional to the amount of chlorophyll present in the leaf. In order to convert these values into absolute units of chlorophyll concentration, calibration curves must be derived and utilized. Here, we present calibration equations for Arabidopsis that can be used to convert SPAD values into total chlorophyll per unit leaf area (nmol/cm(2); R(2) = 0.9960) or per unit fresh weight of leaf tissue (nmol/mg; R(2) = 0.9809). These relationships were derived using a series of Arabidopsis chloroplast biogenesis mutants that exhibit chlorophyll deficiencies of varying severity, and were verified by the subsequent analysis of senescent or light-stressed leaves. Our results revealed that the converted SPAD values differ from photometric measurements of solvent-extracted chlorophyll by just ~6% on average.

Physical associations to spring phytoplankton biomass interannual variability in the U.S. Northeast Continental Shelf

NASA Astrophysics Data System (ADS)

Saba, Vincent S.; Hyde, Kimberly J. W.; Rebuck, Nathan D.; Friedland, Kevin D.; Hare, Jonathan A.; Kahru, Mati; Fogarty, Michael J.

2015-02-01

The continental shelf of the Northeast United States and Nova Scotia is a productive marine ecosystem that supports a robust biomass of living marine resources. Understanding marine ecosystem sensitivity to changes in the physical environment can start with the first-order response of phytoplankton (i.e., chlorophyll a), the base of the marine food web. However, the primary physical associations to the interannual variability of chlorophyll a in these waters are unclear. Here we used ocean color satellite measurements and identified the local and remote physical associations to interannual variability of spring surface chlorophyll a from 1998 to 2013. The highest interannual variability of chlorophyll a occurred in March and April on the northern flank of Georges Bank, the western Gulf of Maine, and Nantucket Shoals. Complex interactions between winter wind speed over the Shelf, local winter water levels, and the relative proportions of Atlantic versus Labrador Sea source waters entering the Gulf of Maine from the previous summer/fall were associated with the variability of March/April chlorophyll a in Georges Bank and the Gulf of Maine. Sea surface temperature and sea surface salinity were not robust correlates to spring chlorophyll a. Surface nitrate in the winter was not a robust correlate to chlorophyll a or the physical variables in every case suggesting that nitrate limitation may not be the primary constraint on the interannual variability of the spring bloom throughout all regions. Generalized linear models suggest that we can resolve 88% of March chlorophyll a interannual variability in Georges Bank using lagged physical data.

The relationship between concentration of clorophyll-a with skipjack (Katsuwonus pelamis, Linnaeus 1758) production at West Sumatera waters, Indonesia

NASA Astrophysics Data System (ADS)

Usman; Ersti Yulika Sari, T.; Syaifuddin; Audina

2017-01-01

The regression and correlation technic was uses to evaluated the contribution of chlorophyll-a concentration on variation of longline skipjack tuna production. An analysis was performed by placing Chlorophyll-a as predictor and Skipjack (Katsuwonus pelamis, Linnaeus 1758) production as dependent variable, using Chlorophyll-a derived from NPP VIIRS, and CPUE derived from longline fisherman log books for the year of 2013. Chlorophyll-a distribution which derived from NPP VIIRS between 0.13-0.26 mg/m3 whereas maximum CPUE as much as 0,1875 kg/trip in April. The regression equation obtained was CPUE = -1.12 + 11.5 Chl-a. Correlation between chlorophyll-a and CPUE have moderate relationship (r=0.51). From regression equation for those variables showed that the variation of chlorophyll-a had affected about 26% on variation of CPUE, only.

A new method to generate a high-resolution global distribution map of lake chlorophyll

USGS Publications Warehouse

Sayers, Michael J; Grimm, Amanda G.; Shuchman, Robert A.; Deines, Andrew M.; Bunnell, David B.; Raymer, Zachary B; Rogers, Mark W.; Woelmer, Whitney; Bennion, David; Brooks, Colin N.; Whitley, Matthew A.; Warner, David M.; Mychek-Londer, Justin G.

2015-01-01

A new method was developed, evaluated, and applied to generate a global dataset of growing-season chlorophyll-a (chl) concentrations in 2011 for freshwater lakes. Chl observations from freshwater lakes are valuable for estimating lake productivity as well as assessing the role that these lakes play in carbon budgets. The standard 4 km NASA OceanColor L3 chlorophyll concentration products generated from MODIS and MERIS sensor data are not sufficiently representative of global chl values because these can only resolve larger lakes, which generally have lower chl concentrations than lakes of smaller surface area. Our new methodology utilizes the 300 m-resolution MERIS full-resolution full-swath (FRS) global dataset as input and does not rely on the land mask used to generate standard NASA products, which masks many lakes that are otherwise resolvable in MERIS imagery. The new method produced chl concentration values for 78,938 and 1,074 lakes in the northern and southern hemispheres, respectively. The mean chl for lakes visible in the MERIS composite was 19.2 ± 19.2, the median was 13.3, and the interquartile range was 3.90–28.6 mg m−3. The accuracy of the MERIS-derived values was assessed by comparison with temporally near-coincident and globally distributed in situmeasurements from the literature (n = 185, RMSE = 9.39, R2 = 0.72). This represents the first global-scale dataset of satellite-derived chl estimates for medium to large lakes.

Temporal Relationships Between African Dust and Chlorophyll-a in the Eastern Caribbean Basin

NASA Astrophysics Data System (ADS)

Gomez-Andujar, N. X.; Mayol-Bracero, O. L.; Torres-Delgado, E.

2017-12-01

Seasonal African Dust (AD) transports soluble iron to oligotrophic Caribbean waters, and when bioavailable, it could increase marine primary productivity (PP). Recently, the region has experienced the proliferation of unusually high quantities of Sargassum, an iron-absorbing macroalgae inhabiting the air-sea interface, which possess ecological and economic challenges and whose driving factors are still uncertain. AD events reach Puerto Rico (PR) mostly during boreal summer months. This is also the season when chlorophyll-α (CHL) concentrations are highest, when the algae starts to bloom, and when sediment plumes from the Orinoco River (ORP) also reach nutrient discharge maxima.This study seeks to better understand the temporal relationships between increases in chlorophyll-α and the presence of african dust events in the region. Aerosol data collected at the Cabezas de San Juan Atmospheric Observatory was used to identify AD events between January 2005 and December 2015. Light scattering coefficients were measured with an integrating Nephelometer, while light absorption coefficients were obtained from either the Particle Soot/Absorption Photometer (PSAP) or the Continuous Light Absorption Photometer (CLAP). Spectral properties suggesting AD events were cross-referenced with surface dust concentration image models and source-attributed air masses corresponding to dusty periods using Hybrid Single-Particle Lagrangian Integrated Trajectories (HYSPLIT). For all years with spectral data, modeled monthly wet dust deposition was correlated (r=0.64) with mean CHL concentrations from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). Daily dust mass column densities from NASA's MERRA-2 model were also correlated (r2= 0.53) to sea surface iron concentrations from NASA's Ocean Biogeochemical Model. We present the 2010 case study, which coincides with the start of the Sargassum bloom and shows CHL peaks occurring a month before ORPs but during the AD season, suggesting the AD role in enhancing PP. Other possible influencing climatic and oceanographic variables could be associated to these observations. Further efforts include spatially linking the Floating Algae Index in satellite imagery to AD concentrations, to better predict harmful algal blooms and inform management.

Environmental dynamics of red Noctiluca scintillans bloom in tropical coastal waters.

PubMed

Baliarsingh, S K; Lotliker, Aneesh A; Trainer, Vera L; Wells, Mark L; Parida, Chandanlal; Sahu, Biraja K; Srichandan, Suchismita; Sahoo, Subhashree; Sahu, K C; Kumar, T Sinivasa

2016-10-15

An intense bloom of red Noctiluca scintillans (NS) occurred off the Rushikulya estuarine region along the east coast of India, an important site for mass nesting events of the vulnerable Olive Ridley sea turtle. At its peak, densities of NS were 3.3×10(5) cells-l(-1), with low relative abundance of other phytoplankton. The peak bloom coincided with high abundance of gelatinous planktivores which may have facilitated bloom development by their grazing on other zooplankton, particularly copepods. Ammonium concentrations increased by approximately 4-fold in the later stages of bloom, coincident with stable NS abundance and chlorophyll concentrations in the nano- and microplankton. This increase likely was attributable to release of intracellular ammonium accumulated through NS grazing. Dissolved oxygen concentrations decreased in sub-surface waters to near hypoxia. Micro-phytoplankton increasingly dominated chlorophyll-a biomass as the bloom declined, with diminishing picoplankton abundance likely the result of high predation by the ciliate Mesodinium rubrum. Together, these data illustrate factors that can disrupt ecosystem balance in this critically important Indian coastal region. Copyright © 2016 Elsevier Ltd. All rights reserved.

Response of Two Plant Species to Two Ultraviolet-B Radiation Regimes

NASA Technical Reports Server (NTRS)

Levy, Daniel L.; Skiles, J. W.; Peterson, David (Technical Monitor)

1996-01-01

The depleted stratospheric ozone layer has been directly linked to increased levels of ultraviolet radiation at the earth's surface. It is important to understand what effect this will have on plants. We tested the hypothesis that in response to increased UV-B radiation (280-320 man), soybean (Glycine max Merrill) and alfalfa (Mercado Saliva L.) would produce higher concentrations of flavonoids than plants screened from UV-B. Soybean and alfalfa plants were grown successively in a growth chamber that provided UV-B radiation intensities 45% above summer field levels. A wooden frame was used to suspend mylar-D film over one group of plants and mono-acetate film over another group. Mylar is opaque in the 280-316 nm range, and acetate absorbs most radiation from 280-290 nm and then reduces intensities in the 290-320 nm range by roughly 15%. Leaf chlorophyll concentration was determined with a Minolta SPAD-502 chlorophyll meter; the BRAD meter was calibrated with N,N- extractions. Flavonoids were extracted with an acidified methanol/water solution. Soybean grown under the acetate treatment showed 26% smaller internodal lengths and higher concentrations of flavonoids compared to plants grown under mylar. Significant results for alfalfa included 22% greater leaf flavonoid concentration under acetate, 14% greater leaf chlorophyll concentration under mylar, and 32% greater above-ground biomass under mylar. We found that increased UV-B radiation leads to increased production of UV-B absorbing compounds (i.e. flavonoids) in soybean and alfalfa leaves. This suggests that a protective mechanism in these plants is triggered by UV-B. In response, flavonoids are produced that absorb UV-B, and consequently decrease potentially damaging effects to the plants. In addition, we hypothesize that this flavonoid protection mechanism saturates at certain UV-B intensities.

The Impact of Iron Limitation on Remote Sensing Reflectance in Phaeocystis antarctica

NASA Astrophysics Data System (ADS)

Tagliabue, A.; van Dijken, G. L.; Arrigo, K. R.

2006-12-01

The iron limited Southern Ocean is an important controller of the global carbon cycle and is predicted to be heavily impacted by future changes in climate. Such remote regions are heavily reliant on acquiring data from remotely sensed satellite observations of pigment concentrations, via algorithms that utilize bio-optical properties to estimate chlorophyll a concentrations. The haptophyte Phaeocystis antarctica is a key phytoplankton functional group across the Southern Ocean and dominates phytoplankton biomass in the highly productive southwestern Ross Sea. In this study, we examine absorption spectra obtained from laboratory cultures of P. antarctica grown under iron sufficient and deficient conditions. We then utilize a semi-analytical reflectance model, alongside data collected from the Ross Sea, to compare remote sensing reflectance (Rrs) derived from absorption spectra to chlorophyll a. We find that Rrs(490):Rrs(555) per unit chlorophyll a for iron sufficient P. antarctica is consistent with the existing Ross Sea algorithm. However, the increased chlorophyll specific absorption at 490 and 555 nm of iron deficient P. antarctica results in a reduction in Rrs(490):Rrs(555) per unit chlorophyll a. Therefore, remotely sensed chlorophyll a concentrations based on Rrs(490):Rrs(555) will be overestimated when waters dominated by P. antarctica experience iron stress. If remotely sensed chlorophyll a concentrations are erroneously high when P. antarctica is iron limited, then both the magnitude and duration of P. antarctica blooms might have been overestimated. We suggest that an in situ investigation of the P. antarctica Rrs to chlorophyll a relationship is necessary during the onset of iron limitation. The likely causes and broader implications of these conclusions will also be discussed.

Recent Trends in Global Ocean Chlorophyll

NASA Technical Reports Server (NTRS)

Gregg, Watson; Casey, Nancy

2004-01-01

Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 5% since 1998. The North Pacific ocean basin has increased nearly 19%. To understand the causes of these trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The mode1 utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. Ths enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll.

Assessing the Skill of Chlorophyll Forecasts: Latest Development and Challenges Ahead Using the Case of the Equatorial Pacific

NASA Technical Reports Server (NTRS)

Rousseaux, Cecile S.; Gregg, Watson W.

2018-01-01

Using a global ocean biogeochemical model combined with a forecast of physical oceanic and atmospheric variables from the NASA Global Modeling and Assimilation Office, we assess the skill of a chlorophyll concentrations forecast in the Equatorial Pacific for the period 2012-2015 with a focus on the forecast of the onset of the 2015 El Nino event. Using a series of retrospective 9-month hindcasts, we assess the uncertainties of the forecasted chlorophyll by comparing the monthly total chlorophyll concentration from the forecast with the corresponding monthly ocean chlorophyll data from the Suomi-National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP VIIRS) satellite. The forecast was able to reproduce the phasing of the variability in chlorophyll concentration in the Equatorial Pacific, including the beginning of the 2015-2016 El Nino. The anomaly correlation coefficient (ACC) was significant (p less than 0.05) for forecast at 1-month (R=0.33), 8-month (R=0.42) and 9-month (R=0.41) lead times. The root mean square error (RMSE) increased from 0.0399 microgram chl L(exp -1) for the 1-month lead forecast to a maximum of 0.0472 microgram chl L(exp -1) for the 9-month lead forecast indicating that the forecast of the amplitude of chlorophyll concentration variability was getting worse. Forecasts with a 3-month lead time were on average the closest to the S-NPP VIIRS data (23% or 0.033 microgram chl L(exp -1)) while the forecast with a 9-month lead time were the furthest (31% or 0.042 microgram chl L(exp -1)). These results indicate the potential for forecasting chlorophyll concentration in this region but also highlights various deficiencies and suggestions for improvements to the current biogeochemical forecasting system. This system provides an initial basis for future applications including the effects of El Nino events on fisheries and other ocean resources given improvements identified in the analysis of these results.

Forecasting Ocean Chlorophyll in the Equatorial Pacific.

PubMed

Rousseaux, Cecile S; Gregg, Watson W

2017-01-01

Using a global ocean biogeochemical model combined with a forecast of physical oceanic and atmospheric variables from the NASA Global Modeling and Assimilation Office, we assess the skill of a chlorophyll concentrations forecast in the Equatorial Pacific for the period 2012-2015 with a focus on the forecast of the onset of the 2015 El Niño event. Using a series of retrospective 9-month hindcasts, we assess the uncertainties of the forecasted chlorophyll by comparing the monthly total chlorophyll concentration from the forecast with the corresponding monthly ocean chlorophyll data from the Suomi-National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP VIIRS) satellite. The forecast was able to reproduce the phasing of the variability in chlorophyll concentration in the Equatorial Pacific, including the beginning of the 2015-2016 El Niño. The anomaly correlation coefficient (ACC) was significant ( p < 0.05) for forecast at 1-month ( R = 0.33), 8-month ( R = 0.42) and 9-month ( R = 0.41) lead times. The root mean square error (RMSE) increased from 0.0399 μg chl L -1 for the 1-month lead forecast to a maximum of 0.0472 μg chl L -1 for the 9-month lead forecast indicating that the forecast of the amplitude of chlorophyll concentration variability was getting worse. Forecasts with a 3-month lead time were on average the closest to the S-NPP VIIRS data (23% or 0.033 μg chl L -1 ) while the forecast with a 9-month lead time were the furthest (31% or 0.042 μg chl L -1 ). These results indicate the potential for forecasting chlorophyll concentration in this region but also highlights various deficiencies and suggestions for improvements to the current biogeochemical forecasting system. This system provides an initial basis for future applications including the effects of El Niño events on fisheries and other ocean resources given improvements identified in the analysis of these results.

Increased temperature and altered summer precipitation have differential effects on biological soil crusts in a dryland ecosystem

USGS Publications Warehouse

Johnson, Shannon L.; Kuske, Cheryl R.; Carney, Travis D.; Housman, David C.; Gallegos-Graves, La Verne; Belnap, Jayne

2012-01-01

Biological soil crusts (biocrusts) are common and ecologically important members of dryland ecosystems worldwide, where they stabilize soil surfaces and contribute newly fixed C and N to soils. To test the impacts of predicted climate change scenarios on biocrusts in a dryland ecosystem, the effects of a 2–3 °C increase in soil temperature and an increased frequency of smaller summer precipitation events were examined in a large, replicated field study conducted in the cold desert of the Colorado Plateau, USA. Surface soil biomass (DNA concentration), photosynthetically active cyanobacterial biomass (chlorophyll a concentration), cyanobacterial abundance (quantitative PCR assay), and bacterial community composition (16S rRNA gene sequencing) were monitored seasonally over 2 years. Soil microbial biomass and bacterial community composition were highly stratified between the 0–2 cm depth biocrusts and 5–10 cm depth soil beneath the biocrusts. The increase in temperature did not have a detectable effect on any of the measured parameters over 2 years. However, after the second summer of altered summer precipitation pattern, significant declines occurred in the surface soil biomass (avg. DNA concentration declined 38%), photosynthetic cyanobacterial biomass (avg. chlorophyll a concentration declined 78%), cyanobacterial abundance (avg. gene copies g−1 soil declined 95%), and proportion of Cyanobacteria in the biocrust bacterial community (avg. representation in sequence libraries declined 85%). Biocrusts are important contributors to soil stability, soil C and N stores, and plant performance, and the loss or reduction of biocrusts under an altered precipitation pattern associated with climate change could contribute significantly to lower soil fertility and increased erosion and dust production in dryland ecosystems at a regional scale.

Response of Two Legumes to Two Ultraviolet-B Radiation Regimes

NASA Technical Reports Server (NTRS)

Levy, Daniel L.; Skiles, J. W.

2000-01-01

Depletion of the stratospheric ozone layer has been directly linked to increased levels of UV radiation at the earth's surface. The purpose of this study was to evaluate the responses of soybean (Glycine max) and alfalfa (Medicago sativa) to increased UV-B radiation (280-320 nm). Soybean and alfalfa were grown successively in a growth chamber that provided UV-B intensities 45% above nominal summer field levels. Mylar-D (UVB opaque) and mono-acetate (UV-B transparent) films were used to establish the two UV-B treatments. Soybean grown under increased UV showed 21% smaller internodal lengths and higher concentrations of UV-B absorbing pigments (i.e. flavonoids) compared to plants grown under no UV. Significant results for alfalfa included 22% greater leaf flavonoid concentration under increased UV, 14% greater leaf chlorophyll concentration under no UV, and 32% greater above-ground biomass with no UV. These leguminous species possess mechanisms that protect against UV-B damage as indicated by increases in foliar concentrations of UV-B absorbing compounds. Alfalfa appears to be more sensitive to UV-B damage than soybean. Remote sensing of chlorophyll fluorescence may offer a means of monitoring UV-induced plant stress and damage.

Remote Sensing Reflectance and Inherent Optical Properties in the Mid-mesohaline Chesapeake Bay

NASA Technical Reports Server (NTRS)

Tzortziou, Maria; Subramaniam, Ajit; Herman, Jay R.; Gallegos, Charles L.; Neal, Patrick J.; Harding, Lawrence W., Jr.

2006-01-01

We used an extensive set of bio-optical data and radiative transfer (RT) model simulations of radiation fields to investigate relationships between inherent optical properties and remotely sensed quantities in the optically complex, mid-mesohaline Chesapeake Bay waters. Field observations showed that the chlorophyll algorithms used by the MODIS (MODerate resolution Imaging Spectroradiometer) ocean color sensor (i.e. Chlor_a, chlor_MODIS, chlor_a_3 products) do not perform accurately in these Case 2 waters. This is because, when applied to waters with high concentrations of chlorophyll, all MODIS algorithms are based on empirical relationships between chlorophyll concentration and blue-green wavelength remote sensing reflectance (Rrs) ratios that do not account for the typically strong blue-wavelength absorption by non-covarying, dissolved and non-algal particulate components. Stronger correlation was observed between chlorophyll concentration and Rrs ratios in the red (i.e. Rrs(677)/Rrs(554)) where dissolved and non-algal particulate absorption become exponentially smaller. Regionally-specific algorithms that are based on the phytoplankton optical properties in the red wavelength region provide a better basis for satellite monitoring of phytoplankton blooms in these Case 2 waters. Good optical closure was obtained between independently measured Rrs spectra and the optical properties of backscattering, b(sub b), and absorption, a, over the wide range of in-water conditions observed in the Chesapeake Bay. Observed variability in the quantity f/Q (proportionality factor in the relationship between Rrs and the water inherent optical properties ratio b(sub b)/(a+b(sub b)) was consistent with RT model calculations for the specific measurement geometry and water bio-optical characteristics. Data and model results showed that f/Q values in these Case 2 coastal waters are not considerably different from those estimated in previous studies for Case 1 waters. Variation in surface backscattering significantly affected Rrs magnitude across the visible spectrum and was most strongly correlated (R(sup 2)=0.88) with observed variability in Rrs at 670 nm. Surface values of particulate backscattering were strongly correlated with non-algal particulate absorption, a(sub nap), in the blue wavelengths (R(sup 2)=0.83). These results, along with the measured values of backscattering fraction magnitude and non-algal particulate absorption spectral slope, suggest that suspended non-algal particles with high inorganic content are the major water constituents regulating b(sub b) variability in the mid-mesohaline Chesapeake Bay. Remote retrieval of surface b(sub b) and (a(sub nap), from Rrs(670) can be used in regionally-specific satellite algorithms to separate contribution by non-algal particles and dissolved organic matter to total light absorption in the blue, and monitor non-algal suspended particle concentration and distribution in these Case 2 waters.

RELATIONSHIPS BETWEEN SUMMER CONCENTRATIONS OF TOTAL NITROGEN AND CHLOROPHYLL A IN TEN COASTAL SYSTEMS IN THE EASTERN UNITED STATES

EPA Science Inventory

We have examined relationships between summer (JuneAugust) average concentrations of total nitrogen (TN) and chlorophyll a (chl a) concentrations in the near-shore Mid-Atlantic Bight and nine bays and estuaries in the eastern United States: Boston Harbor/Massachusetts Bay, Long I...

Surface Characteristics of Green Island Wakes from Satellite Imagery

NASA Astrophysics Data System (ADS)

Cheng, Kai-Ho; Hsu, Po-Chun; Ho, Chung-Ru

2017-04-01

Characteristics of an island wake induced by the Kuroshio Current flows pass by Green Island, a small island 40 km off southeast of Taiwan is investigated by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery. The MODIS sea surface temperature (SST) and chlorophyll-a (chl-a) imagery is produced at 250-meter resolution from 2014 to 2015 using the SeaDAS software package which is developed by the National Aeronautics and Space Administration. The wake occurrence is 59% observed from SST images during the data span. The average cooling area is 190 km2, but the area is significantly changed with wind directions. The wake area is increased during southerly winds and is reduced during northerly winds. Besides, the average cooling SST was about 2.1 oC between the front and rear island. Comparing the temperature difference between the wake and its left side, the difference is 1.96 oC. In addition, the wakes have 1 3 times higher than normal in chlorophyll concentration. The results indicate the island mass effect makes the surface water of Green island wake colder and chl-a higher.

Remote measurement of turbidity and chlorophyll through aerial photography

NASA Technical Reports Server (NTRS)

Schwebel, M. D.; James, W. P.; Clark, W. J.

1973-01-01

Studies were conducted utilizing six different film and filter combinations to quantitatively detect chlorophyll and turbidity in six farm ponds. The low range of turbidity from 0-35 JTU correlated well with the density readings from the green band of normal color film and the high range above 35 JTU was found to correlate with density readings in the red band of color infrared film. The effect of many of the significant variables can be reduced by using standardized procedures in taking the photography. Attempts to detect chlorophyll were masked by the turbidity. The ponds which were highly turbid also had high chlorophyll concentrations; whereas, the ponds with low turbidity also had low chlorophyll concentrations. This prevented a direct correlation for this parameter. Several suggested approaches are cited for possible future investigations.

Ocean Color and the Equatorial Annual Cycle in the Pacific

NASA Astrophysics Data System (ADS)

Hammann, A. C.; Gnanadesikan, A.

2012-12-01

The presence of chlorophyll, colored dissolved organic matter (CDOM) and other scatterers in ocean surface waters affect the flux divergence of solar radiation and thus the vertical distribution of radiant heating of the ocean. While this may directly alter the local mixed-layer depth and temperature (Martin 1985; Strutton & Chavez 2004), non-local changes are propagated through advection (Manizza et al. 2005; Murtugudde et al. 2002; Nakamoto et al. 2001; Sweeny et al. 2005). In and coupled feedbacks (Lengaigne et al. 2007; Marzeion & Timmermann 2005). Anderson et al. (2007), Anderson et al. (2009) and Gnanadesikan & Anderson (2009) have performed a series of experiments with a fully coupled climate model which parameterizes the e-folding depth of solar irradiance in terms of surface chlorophyll-a concentration. The results have so far been discussed with respect to the climatic mean state and ENSO variability in the tropical Pacific. We extend the discussion here to the Pacific equatorial annual cycle. The focus of the coupled experiments has been the sensitivity of the coupled system to regional differences in chlorophyll concentration. While runs have been completed with realistic SeaWiFS-derived monthly composite chlorophyll ('green') and with a globally chlorophyll-free ocean ('blue'), the concentrations in two additional runs have been selectively set to zero in specific regions: the oligotrophic subtropical gyres ('gyre') in one case and the mesotrophic gyre margins ('margin') in the other. The annual cycle of ocean temperatures exhibits distinctly reduced amplitudes in the 'blue' and 'margin' experiments, and a slight reduction in 'gyre' (while ENSO variability almost vanishes in 'blue' and 'gyre', but amplifies in 'margin' - thus the frequently quoted inverse correlation between ENSO and annual amplitudes holds only for the 'green' / 'margin' comparison). It is well-known that on annual time scales, the anomalous divergence of surface currents and vertical upwelling acting on a mean temperature field contribute the largest term to SST variability (Köberle & Philander 1994; Li & Philander 1996). We examine whether it is changes in the surface currents (driven by the annual cycle of winds) or changes in the mean temperature fields (driven by enhanced penetration of solar radiation) that drive the differences between the coupled models. We do this using a simple linear equatorial-wave model, which, when forced with an annual harmonic of wind stresses, reproduces the essential characteristics of annual ocean current anomalies. The model solves the linearized Boussinesq equations by expansion into discrete modes in all spatial dimensions (McCreary 1981; Lighthill 1969). Both the wind forcing and the (laterally homogeneous) background density profile are constructed as approximations to the coupled model fields. The annual perturbation currents from the wave model are then used to advect the mean temperature fields from the coupled model experiments. While the difference in the mean stratification explains the difference between the 'green' and 'blue' cases. For the other two cases, it appears that changes in the annual wind fields need also be taken into account. An initial hypothesis is that the hemispheric asymmetry in the annual amplitude of wind stress curl that is most important in setting the amplitude of the annual cycle on the equator.

Linking land use changes to surface water quality variability in Lake Victoria: some insights from remote sensing

NASA Astrophysics Data System (ADS)

Mugo, R. M.; Limaye, A. S.; Nyaga, J. W.; Farah, H.; Wahome, A.; Flores, A.

2016-12-01

The water quality of inland lakes is largely influenced by land use and land cover changes within the lake's catchment. In Africa, some of the major land use changes are driven by a number of factors, which include urbanization, intensification of agricultural practices, unsustainable farm management practices, deforestation, land fragmentation and degradation. Often, the impacts of these factors are observable on changes in the land cover, and eventually in the hydrological systems. When the natural vegetation cover is reduced or changed, the surface water flow patterns, water and nutrient retention capacities are also changed. This can lead to high nutrient inputs into lakes, leading to eutrophication, siltation and infestation of floating aquatic vegetation. To assess the relationship between land use and land cover changes in part of the Lake Victoria Basin, a series of land cover maps were derived from Landsat imagery. Changes in land cover were identified through change maps and statistics. Further, the surface water chlorophyll-a concentration and turbidity were derived from MODIS-Aqua data for Lake Victoria. Chlrophyll-a and turbidity are good proxy indicators of nutrient inputs and siltation respectively. The trends in chlorophyll-a and turbidity concentrations were analyzed and compared to the land cover changes over time. Certain land cover changes related to agriculture and urban development were clearly identifiable. While these changes might not be solely responsible for variability in chlrophyll-a and turbidity concentrations in the lake, they are potentially contributing factors to this problem. This work illustrates the importance of addressing watershed degradation while seeking to solve water quality related problems.

Phase 2 development of Great Lakes algorithms for Nimbus-7 coastal zone color scanner

NASA Technical Reports Server (NTRS)

Tanis, Fred J.

1984-01-01

A series of experiments have been conducted in the Great Lakes designed to evaluate the application of the NIMBUS-7 Coastal Zone Color Scanner (CZCS). Atmospheric and water optical models were used to relate surface and subsurface measurements to satellite measured radiances. Absorption and scattering measurements were reduced to obtain a preliminary optical model for the Great Lakes. Algorithms were developed for geometric correction, correction for Rayleigh and aerosol path radiance, and prediction of chlorophyll-a pigment and suspended mineral concentrations. The atmospheric algorithm developed compared favorably with existing algorithms and was the only algorithm found to adequately predict the radiance variations in the 670 nm band. The atmospheric correction algorithm developed was designed to extract needed algorithm parameters from the CZCS radiance values. The Gordon/NOAA ocean algorithms could not be demonstrated to work for Great Lakes waters. Predicted values of chlorophyll-a concentration compared favorably with expected and measured data for several areas of the Great Lakes.

Patterns and Variability in Global Ocean Chlorophyll: Satellite Observations and Modeling

NASA Technical Reports Server (NTRS)

Gregg, Watson

2004-01-01

Recent analyses of SeaWiFS data have shown that global ocean chlorophyll has increased more than 4% since 1998. The North Pacific ocean basin has increased nearly 19%. These trend analyses follow earlier results showing decadal declines in global ocean chlorophyll and primary production. To understand the causes of these changes and trends we have applied the newly developed NASA Ocean Biogeochemical Assimilation Model (OBAM), which is driven in mechanistic fashion by surface winds, sea surface temperature, atmospheric iron deposition, sea ice, and surface irradiance. The model utilizes chlorophyll from SeaWiFS in a daily assimilation. The model has in place many of the climatic variables that can be expected to produce the changes observed in SeaWiFS data. This enables us to diagnose the model performance, the assimilation performance, and possible causes for the increase in chlorophyll. A full discussion of the changes and trends, possible causes, modeling approaches, and data assimilation will be the focus of the seminar.

Evaluation of the Harmful Algal Bloom Mapping System (HABMapS) and Bulletin

NASA Technical Reports Server (NTRS)

Hall, Callie; Zanoni, Vicki; Estep, Leland; Terrie, Gregory; D'Sa, Eurico; Pagnutti, Mary

2004-01-01

The National Oceanic and Atmospheric Administration (NOAA) Harmful Algal Bloom (HAB) Mapping System and Bulletin provide a Web-based geographic information system (GIS) and an e-mail alert system that allow the detection, monitoring, and tracking of HABs in the Gulf of Mexico. NASA Earth Science data that potentially support HABMapS/Bulletin requirements include ocean color, sea surface temperature (SST), salinity, wind fields, precipitation, water surface elevation, and ocean currents. Modeling contributions include ocean circulation, wave/currents, along-shore current regimes, and chlorophyll modeling (coupled to imagery). The most immediately useful NASA contributions appear to be the 1-km Moderate Resolution Imaging Spectrometer (MODIS) chlorophyll and SST products and the (presently used) SeaWinds wind vector data. MODIS pigment concentration and SST data are sufficiently mature to replace imagery currently used in NOAA HAB applications. The large file size of MODIS data is an impediment to NOAA use and modified processing schemes would aid in NOAA adoption of these products for operational HAB forecasting.

Evaluation of phytoplankton community composition in the eutrophic Masan Bay by HPLC pigment analysis.

PubMed

Kim, Jeong Bae; Hong, Sokjin; Lee, Won-Chan; Lee, Yong-Woo; Kim, Hyung Chul; Cho, Yoonsik

2015-03-01

To assess the spatiotemporal changes in phytoplankton community composition in relation to the environment of Masan Bay, a semi-enclosed bay on the southern coast of Korea, photosynthetic pigments and environmental variables were analyzed in seawater, every month between March and November 2010. The level of dissolved inorganic nutrients was highest between July and September when the freshwater influx was at its peak, whereas chlorophyll a level was highest in April and August. Phosphate concentration was low in April (average: 0.22 +/- 0.17 microM), indicating the role of phosphate as a growth-limiting factor for phytoplankton. The results of pigment analysis indicate that dinoflagellate blooms occurred under favorable conditions, where competition with diatoms occurred. Fucoxanthin- and chlorophyll b-containing phytoplankton dominated the surface layer of Masan Bay from July to September. The composition of phytoplankton community in Masan Bay changed dramatically each month according to variations in the amount and composition of nutrients introduced through surface runoff.

Improving Assessments of Chlorophyll Concentration From In Situ Optical Measurements

NASA Astrophysics Data System (ADS)

Nardelli, S.; Twardowski, M.

2016-02-01

Florescence as a chlorophyll proxy has poor accuracy because it is dependent on specific absorption (effective molar absorptivity of packaged chlorophyll in living cells) and fluorescence quantum yield, both of which are highly variable. Absorption is a better proxy, as it is only dependent on specific absorption for packaged chlorophyll, although excepted accuracy in using a nominal specific absorption for all phytoplankton is still about 50%. Bricaud et al. (1995), Ciotti et al. (2002), Mouw et al. (2010), etc. have shown, however, that specific absorption is closely related to the average size of phytoplankton due to the relative packaging effect. Through other methods that have been developed over the years (Morel 1973; Diehl and Haart 1980; Boss et al. 2001; Slade and Boss 2015), it has been shown that measurements of spectral particulate attenuation (i.e., light transmission), and perhaps spectral particulate backscattering, can be used as simple proxies for the average size of the particle field. We therefore test the hypothesis that information on average particle size may be used to better estimate specific absorption for packaged chlorophyll, possibly enabling more accurate retrievals of chlorophyll concentration from optical measurements. The required optical measurements can be made with compact commercial off-the-shelf sensors with high sampling frequency that can be operated from autonomous vehicles; as a result, derived chlorophyll concentration could be resolved at far higher temporal and spatial frequency than is currently possible through extracting chlorophyll from discretely collected samples. This study examines the relationship between specific absorption and the attenuation spectral slope in extensive datasets from Case I and Case II waters found globally in an attempt to assess the link between pigment packaging and phytoplankton size dynamics and the impact on improving the derivation of chlorophyll from in situ optical measurements.

Spatial and Temporal Patterns of Chlorophyll Concentration in the Southern California Bight

NASA Astrophysics Data System (ADS)

Nezlin, Nikolay P.; McLaughlin, Karen; Booth, J. Ashley T.; Cash, Curtis L.; Diehl, Dario W.; Davis, Kristen A.; Feit, Adriano; Goericke, Ralf; Gully, Joseph R.; Howard, Meredith D. A.; Johnson, Scott; Latker, Ami; Mengel, Michael J.; Robertson, George L.; Steele, Alex; Terriquez, Laura; Washburn, Libe; Weisberg, Stephen B.

2018-01-01

Distinguishing between local, anthropogenic nutrient inputs and large-scale climatic forcing as drivers of coastal phytoplankton biomass is critical to developing effective nutrient management strategies. Here we assess the relative importance of these two drivers by comparing trends in chlorophyll-a between shallow coastal (0.1-16.5 km) and deep offshore (17-700 km) areas, hypothesizing that coastal regions influenced by anthropogenic nutrient inputs may have different spatial and temporal patterns in chlorophyll-a concentration from offshore regions where coastal inputs are less influential. Quarterly conductivity-temperature-depth (CTD) fluorescence measurements collected from three southern California continental shelf regions since 1998 were compared to chlorophyll-a data from the more offshore California Cooperative Fisheries Investigations (CalCOFI) program. The trends in the coastal zone were similar to those offshore, with a gradual increase of chlorophyll-a biomass and shallowing of its maximum layer since the beginning of observations, followed by chlorophyll-a declining and deepening from 2010 to present. An exception was the northern coastal part of SCB, where chlorophyll-a continued increasing after 2010. The long-term increase in chlorophyll-a prior to 2010 was correlated with increased nitrate concentrations in deep waters, while the recent decline was associated with deepening of the upper mixed layer, both linked to the low-frequency climatic cycles of the Pacific Decadal Oscillation and North Pacific Gyre Oscillation. These large-scale factors affecting the physical structure of the water column may also influence the delivery of nutrients from deep ocean outfalls to the euphotic zone, making it difficult to distinguish the effects of anthropogenic inputs on chlorophyll along the coast.

Toward a multivariate reanalysis of the North Atlantic ocean biogeochemistry during 1998-2006 based on the assimilation of SeaWiFS chlorophyll data

NASA Astrophysics Data System (ADS)

Fontana, C.; Brasseur, P.; Brankart, J.-M.

2012-04-01

Today, the routine assimilation of satellite data into operational models of the ocean circulation is mature enough to enable the production of global reanalyses describing the ocean circulation variability during the past decades. The expansion of the "reanalysis" concept from ocean physics to biogeochemistry is a timely challenge that motivates the present study. The objective of this paper is to investigate the potential benefits of assimilating satellite-estimated chlorophyll data into a basin-scale three-dimensional coupled physical-biogeochemical model of the North-Atlantic. The aim is on one hand to improve forecasts of ocean biogeochemical properties and on the other hand to define a methodology for producing data-driven climatologies based on coupled physical-biogeochemical modelling. A simplified variant of the Kalman filter is used to assimilate ocean color data during a 9 year-long period. In this frame, two experiences are carried out, with and without anamorphic transformations of the state vector variables. Data assimilation efficiency is assessed with respect to the assimilated data set, the nitrate World Ocean Atlas database and a derived climatology. Along the simulation period, the non-linear assimilation scheme clearly improves the surface chlorophyll concentrations analysis and forecast, especially in the North Atlantic bloom region. Nitrate concentration forecasts are also improved thanks to the assimilation of ocean color data while this improvement is limited to the upper layer of the water column, in agreement with recent related litterature. This feature is explained by the weak correlation taken into account by the assimilation between surface phytoplankton and nitrate concentration deeper than 50 m. The assessement of the non-linear assimilation experiments indicates that the proposed methodology provides the skeleton of an assimilative system suitable for reanalysing the ocean biogeochemistry based on ocean color data.

Toward a multivariate reanalysis of the North Atlantic Ocean biogeochemistry during 1998-2006 based on the assimilation of SeaWiFS chlorophyll data

NASA Astrophysics Data System (ADS)

Fontana, C.; Brasseur, P.; Brankart, J.-M.

2013-01-01

Today, the routine assimilation of satellite data into operational models of ocean circulation is mature enough to enable the production of global reanalyses describing the ocean circulation variability during the past decades. The expansion of the "reanalysis" concept from ocean physics to biogeochemistry is a timely challenge that motivates the present study. The objective of this paper is to investigate the potential benefits of assimilating satellite-estimated chlorophyll data into a basin-scale three-dimensional coupled physical-biogeochemical model of the North Atlantic. The aim is on the one hand to improve forecasts of ocean biogeochemical properties and on the other hand to define a methodology for producing data-driven climatologies based on coupled physical-biogeochemical modeling. A simplified variant of the Kalman filter is used to assimilate ocean color data during a 9-year period. In this frame, two experiments are carried out, with and without anamorphic transformations of the state vector variables. Data assimilation efficiency is assessed with respect to the assimilated data set, nitrate of the World Ocean Atlas database and a derived climatology. Along the simulation period, the non-linear assimilation scheme clearly improves the surface analysis and forecast chlorophyll concentrations, especially in the North Atlantic bloom region. Nitrate concentration forecasts are also improved thanks to the assimilation of ocean color data while this improvement is limited to the upper layer of the water column, in agreement with recent related literature. This feature is explained by the weak correlation taken into account by the assimilation between surface phytoplankton and nitrate concentrations deeper than 50 meters. The assessment of the non-linear assimilation experiments indicates that the proposed methodology provides the skeleton of an assimilative system suitable for reanalyzing the ocean biogeochemistry based on ocean color data.

Potential controls of isoprene in the surface ocean

NASA Astrophysics Data System (ADS)

Hackenberg, S. C.; Andrews, S. J.; Airs, R.; Arnold, S. R.; Bouman, H. A.; Brewin, R. J. W.; Chance, R. J.; Cummings, D.; Dall'Olmo, G.; Lewis, A. C.; Minaeian, J. K.; Reifel, K. M.; Small, A.; Tarran, G. A.; Tilstone, G. H.; Carpenter, L. J.

2017-04-01

Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N-45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used.

[Algorithm for estimating chlorophyll-a concentration in case II water body based on bio-optical model].

PubMed

Yang, Wei; Chen, Jin; Mausushita, Bunki

2009-01-01

In the present study, a novel retrieval method for estimating chlorophyll-a concentration in case II waters based on bio-optical model was proposed and was tested with the data measured in the laboratory. A series of reflectance spectra, with which the concentration of each sample constituent (for example chlorophyll-a, NPSS etc.) was obtained from accurate experiments, were used to calculate the absorption and backscattering coefficients of the constituents of the case II waters. Then non-negative least square method was applied to calculate the concentration of chlorophyll-a and non-phytoplankton suspended sediments (NPSS). Green algae was firstly collected from the Kasumigaura lake in Japan and then cultured in the laboratory. The reflectance spectra of waters with different amounts of phytoplankton and NPSS were measured in the dark room using FieldSpec Pro VNIR (Analytical Spectral Devises Inc. , Boulder, CO, USA). In order to validate whether this method can be applied in multispectral data (for example Landsat TM), the spectra measured in the laboratory were resampled with Landsat TM bands 1, 2, 3 and 4. Different combinations of TM bands were compared to derive the most appropriate wavelength for detecting chlorophyll-a in case II water for green algae. The results indicated that the combination of TM bands 2, 3 and 4 achieved much better accuracy than other combinations, and the estimated concentration of chlorophyll-a was significantly more accurate than empirical methods. It is expected that this method can be directly applied to the real remotely sensed image because it is based on bio-optical model.

Recent Ship, Satellite and Autonomous Observations of Southern Ocean Eddies

NASA Astrophysics Data System (ADS)

Strutton, P. G.; Moreau, S.; Llort, J.; Phillips, H. E.; Patel, R.; Della Penna, A.; Langlais, C.; Lenton, A.; Matear, R.; Dawson, H.; Boyd, P. W.

2016-12-01

The Southern Ocean is the area of greatest uncertainty regarding the exchange of CO2 between the ocean and atmosphere. It is also a region of abundant energetic eddies that significantly impact circulation and biogeochemistry. In the Indian sector of the Southern Ocean, cyclonic eddies are unusual in that they are upwelling favorable, as for cyclonic eddies elsewhere, but during summer they are low in silicate and phytoplankton biomass. The reverse is true for anticyclonic eddies in that they have counter-intuitive positive chlorophyll anomalies in summer. Similar but less obvious patterns occur in the Pacific and Atlantic sectors. Using ship, satellite and autonomous observations in the region south of Australia, the physical and biogeochemical signatures of both types of eddies were documented in 2016. A cyclonic eddy that lived for seven weeks exhibited doming isopycnals indicative of upwelling. However, low surface silicate and chlorophyll concentrations appeared to be characteristic of surface waters to the south where the eddy formed. Higher chlorophyll was confined to filaments at the eddy edge. Surface nitrate and phosphate concentrations were more than sufficient for a bloom of non-siliceous phytoplankton to occur. Acoustic observations from a high resolution TRIAXUS transect through the eddy documented high zooplankton biomass in the upper 150m. It is hypothesized that a non-diatom bloom was prevented by grazing pressure, but light may have also been an important limiting resource in late summer (April). Two SOCCOM floats that were deployed in the eddy field continued to monitor the physics, nitrate and bio-optics through the transition to winter. These observations across complementary platforms have identified and then explained the reason for these unexpected biological anomalies in an energetic and globally important region of the global ocean. Understanding the role of eddies in this region will be critical to the representation of mesoscale processes in models used to simulate and project ocean biogeochemistry and carbon uptake.

Relationships between Concentrations of Phytoplankton Chlorophyll a and Total Nitrogen in Ten U.S. Estuaries

EPA Science Inventory

This presentation focuses on the summertime response of phytoplankton chlorophyll to nitrogen concentrations in the upper water columns of ten U.S. estuaries. Using publicly available data from monitoring programs, regression relationships have been developed between summer surfa...

Cross-system comparison of factors influencing chlorophyll-a concentration in Oregon estuaries

EPA Science Inventory

Water column chlorophyll-a (chla) is a proxy for phytoplankton biomass and is often used as a biological response indicator of eutrophication. Although watershed nutrient loading may influence chla concentration in estuaries, factors such as freshwater inflow, residence time, and...

Spatiotemporal chlorophyll-a dynamics on the Louisiana continental shelf derived from a dual satellite imagery algorithm

EPA Science Inventory

A monthly time series of remotely sensed chlorophyll-a (Chlars) over the Louisiana continental shelf (LCS) was developed and examined for its relationship to river discharge, nitrate concentration, total phosphorus concentration, photosynthetically available radiation (PAR), wind...

Modeling chlorophyll-a and dissolved oxygen concentration in tropical floodplain lakes (Paraná River, Brazil).

PubMed

Rocha, R R A; Thomaz, S M; Carvalho, P; Gomes, L C

2009-06-01

The need for prediction is widely recognized in limnology. In this study, data from 25 lakes of the Upper Paraná River floodplain were used to build models to predict chlorophyll-a and dissolved oxygen concentrations. Akaike's information criterion (AIC) was used as a criterion for model selection. Models were validated with independent data obtained in the same lakes in 2001. Predictor variables that significantly explained chlorophyll-a concentration were pH, electrical conductivity, total seston (positive correlation) and nitrate (negative correlation). This model explained 52% of chlorophyll variability. Variables that significantly explained dissolved oxygen concentration were pH, lake area and nitrate (all positive correlations); water temperature and electrical conductivity were negatively correlated with oxygen. This model explained 54% of oxygen variability. Validation with independent data showed that both models had the potential to predict algal biomass and dissolved oxygen concentration in these lakes. These findings suggest that multiple regression models are valuable and practical tools for understanding the dynamics of ecosystems and that predictive limnology may still be considered a powerful approach in aquatic ecology.

Evaluating the impact of sea surface temperature (SST) on spatial distribution of chlorophyll-a concentration in the East China Sea

NASA Astrophysics Data System (ADS)

Ji, Chenxu; Zhang, Yuanzhi; Cheng, Qiuming; Tsou, JinYeu; Jiang, Tingchen; Liang, X. San

2018-06-01

In this study, we analyze spatial and temporal sea surface temperature (SST) and chlorophylla (Chl-a) concentration in the East China Sea (ECS) during the period 2003-2016. Level 3 (4 km) monthly SST and Chl-a data from the Moderate Resolution Imaging Spectroradiometer Satellite (MODIS-Aqua) were reconstructed using the data interpolation empirical orthogonal function (DINEOF) method and used to evaluated the relationship between the two variables. The approaches employed included correlation analysis, regression analysis, and so forth. Our results show that certain strong oceanic SSTs affect Chl-a concentration, with particularly high correlation seen in the coastal area of Jiangsu and Zhejiang provinces. The mean temperature of the high correlated region was 18.67 °C. This finding may suggest that the SST has an important impact on the spatial distribution of Chl-a concentration in the ECS.

Macrophyte disturbance alters aquatic surface microlayer structure, metabolism, and fate.

PubMed

Seliskar, Denise M; Gallagher, John L

2014-03-01

Macrophytes drive the functioning of many salt marsh ecosystem components. We questioned how temporary clearing of the macrophyte community, during restoration, would impact processes at the scale of the aquatic surface microlayer. Development, deposition, and breakup of the tidal creek surface microlayer were followed over tidal cycles seasonally in a cleared "former" Phragmites marsh and an adjacent restored Spartina marsh. Metabolic and physical processes of the mobile surface microlayers and underlying water were compared, along with distribution of organic and inorganic components onto simulated plant stems. In July and October, chlorophyll-a quantities were less on simulated stems in the cleared site than in the restored site. The aquatic microlayer in the cleared site creek exhibited lower photosynthesis and respiration rates, fewer diatoms and green algae, and less chlorophyll-a. There was a lower concentration (250 times) and reduced diversity of fatty acids in the surface microlayer of the cleared site, reflecting a smaller and less diverse microbial community and reduced food resources. Fiddler crab activity was an order of magnitude higher where macrophytes had been cleared. Their consumption of edaphic algae on the mud surface may account for the reduced algae and other organics in the creek surface microlayer, thus representing a redirection of this food resource from creek consumers. Overall, there were less total particulates in the creek surface microlayer at the cleared site, and they dropped out of the surface microlayer sooner in the tidal cycle, resulting in a lower sediment load available for deposit onto marsh surfaces.

Ecophysiological evaluation of tree species for biomonitoring of air quality and identification of air pollution-tolerant species.

PubMed

Sen, Abhishek; Khan, Indrani; Kundu, Debajyoti; Das, Kousik; Datta, Jayanta Kumar

2017-06-01

Identification of tree species that can biologically monitor air pollution and can endure air pollution is very much important for a sustainable green belt development around any polluted place. To ascertain the species, ten tree species were selected on the basis of some previous study from the campus of the University of Burdwan and were studied in the pre-monsoon and post-monsoon seasons. The study has been designed to investigate biochemical and physiological activities of selected tree species as the campus is presently exposed to primary air pollutants and their impacts on plant community were observed through the changes in several physical and biochemical constituents of plant leaves. As the plant species continuously exchange different gaseous pollutants in and out of the foliar system and are very sensitive to gaseous pollutants, they serve as bioindicators. Due to air pollution, foliar surface undergoes different structural and functional changes. In the selected plant species, it was observed that the concentration of primary air pollutants, proline content, pH, relative water holding capacity, photosynthetic rate, and respiration rate were higher in the pre-monsoon than the post-monsoon season, whereas the total chlorophyll, ascorbic acid, sugar, and conductivity were higher in the post-monsoon season. From the entire study, it was observed that the concentration of sulfur oxide (SO x ), nitrogen oxide (NO x ), and suspended particulate matter (SPM) all are reduced in the post-monsoon season than the pre-monsoon season. In the pre-monsoon season, SO x , NO x , and SPM do not have any significant correlation with biochemical as well as physiological parameters. SPM shows a negative relationship with chlorophyll 'a' (r = -0.288), chlorophyll 'b' (r = -0.267), and total chlorophyll (r = -0.238). Similarly, chlorophyll a, chlorophyll b, and the total chlorophyll show negative relations with SO x and NO x (p < 0.005) during the post-monsoon season. Proline shows a positive relationship with SO x in the pre-monsoon season whereas in the post-monsoon season proline content shows a positive relationship with both SO x and NO x . The present study facilitates to screen eight sensitive and two moderately tolerant tree species according to their air pollution tolerance index (APTI) values.

Estimating Chlorophyll Conditions in Southern New England Coastal Waters from Hyperspectral Aircraft Remote Sensing

EPA Science Inventory

Chlorophyll a (chl a) is commonly measured in water quality monitoring programs for coastal and freshwater systems. The concentration of chl a, when evaluated with other condition indicators such as water clarity and dissolved oxygen concentrations, provides information on the en...

Changes in the fluorescence of the Caribbean coral Montastraea faveolata during heat-induced bleaching

USGS Publications Warehouse

Zawada, David G.; Jaffe, J.S.

2003-01-01

In order to evaluate the response of commonly occurring green and orange fluorescent host-based pigments, a thermal stress experiment was performed on specimens of the Caribbean coral Montastraea faveolata. Seven paired samples were collected from a small oceanic reef near Lee Stocking Island in the Bahamas. Seven of the fourteen corals were subjected to elevated temperatures for 28 d, followed by a recovery period lasting 53 d. Throughout the experiment, high-resolution (~400 µm pixel-1) multispectral images of induced fluorescence were recorded at wavelengths corresponding to the green and orange host pigments, plus chlorophyll. These images revealed that the fluorescence of both host pigments was concentrated at polyp centers and declined by 70–90% in regions between polyps. Chlorophyll fluorescence, however, was distributed almost uniformly across the entire coral surface, but with decreases of 10–30% around polyp centers. A normalized difference ratio between the green and orange pigments (GO ratio) was developed to facilitate comparison with chlorophyll fluorescence as a bleaching indicator. Analysis showed a high correspondence between a sustained GO ratio of less than zero and the death of corals. Finally, this ratio was resistant to contamination from other sources of chlorophyll fluorescence, such as filamentous algae.

Linkages between sea-ice coverage, pelagic-benthic coupling, and the distribution of spectacled eiders: observations in March 2008, 2009 and 2010, northern Bering Sea

USGS Publications Warehouse

Cooper, L.W.; Sexson, M.G.; Grebmeier, J.M.; Gradinger, R.; Mordy, C.W.; Lovvorn, J.R.

2013-01-01

Icebreaker-based sampling in the northern Bering Sea south of St. Lawrence Island in March of 2008, 2009, and 2010 has provided new data on overall ecosystem function early in the annual productive cycle. While water-column chlorophyll concentrations (−2 integrated over the whole water column) are two orders of magnitude lower than observed during the spring bloom in May, sea-ice algal inventories of chlorophyll are high (up to 1 g m−3 in the bottom 2-cm of sea-ice). Vertical fluxes of chlorophyll as measured in sediment traps were between 0.3 to 3.7 mg m−2 d−1 and were consistent with the recent deposition (days to weeks time scale) of chlorophyll to the surface sediments (0–25 mg m−2 present at 0–1 cm). Sediment oxygen respiration rates were lower than previous measurements that followed the spring bloom, but were highest in areas of known high benthic biomass. Early spring release of sedimentary ammonium occurs, particularly southeast of St. Lawrence Island, leading to bottom-water ammonium concentrations of >5 µM. These data, together with other physical, biological, and nutrient data are presented here in conjunction with observed sea-ice dynamics and the distribution of an apex predator, the Spectacled Eider (Somateria fischeri). Sea-ice dynamics in addition to benthic food availability, as determined by sedimentation processes, play a role in the distribution of spectacled eiders, which cannot always access the greatest biomass of their preferred bivalve prey. Overall, the data and observations indicate that the northern Bering Sea is biologically active in late winter, but with strong atmospheric and hydrographic controls. These controls pre-determine nutrient and chlorophyll distributions, water-column mixing, as well as pelagic-benthic coupling.

Is It Possible to Distinguish Between Dust and Salt Aerosol Over Waters with Unknown Chlorophyll Concentrations Using Spectral Remote Sensing?

NASA Technical Reports Server (NTRS)

Levy, R. C.; Kaufman, Y. J.

1999-01-01

Atmospheric aerosol has uncertain impacts on the global climate system, as well as on atmospheric and bio-geo-chemical processes of regional and local scales. EOS-MODIS is one example of a satellite sensor designed to improve understanding of the aerosols' type, size and distribution at all temporal and spatial scales. Ocean scientists also plan to use data from EOS-MODIS to assess the temporal and spatial coverage of in-water chlorophyll. MODIS is the first sensor planned to observe the combined ocean-atmosphere system with a wide spectral range (from 410 to 2200 nm). Dust aerosol and salt aerosol have similar spectral signals for wavelengths longer than 550 nm, but because dust selectively absorbs blue light, they have divergent signals in the blue wavelength regions (412 to 490 nm). Chlorophyll also selectively absorbs blue radiation, so that varying chlorophyll concentrations produces a highly varying signal in the blue regions, but less variability in the green, and almost no signal in the red to mid-infrared regions. Thus, theoretically, it may be difficult to differentiate dust and salt in the presence of unknown chlorophyll in the ocean. This study attempts to address the cases in which aerosol and chlorophyll signals can and cannot be separated. For the aerosol spectra, we use the aerosol lookup table from the operational MODIS aerosol-over-ocean algorithm, and for chlorophyll spectra, we use the SeaBAM data set (created for SeaWiFS). We compare the signals using Principal Component Analysis and attempt to retrieve both chlorophyll and aerosol properties using a variant of the operational MODIS aerosol-over-ocean algorithm. Results show that for small optical depths, less than 0.5, it is not possible to differentiate between dust and salt and to determine the chlorophyll concentration at the same time. For larger aerosol optical depths, the chlorophyll signals are comparatively insignificant, and we can hope to distinguish between dust and salt.

Spatial and Temporal Coherence of SeaWiFS Chlorophyll Concentration Anomalies in the North Atlantic Bloom (1998-2005) Examined with Giovanni

NASA Technical Reports Server (NTRS)

Acker, James G.

2006-01-01

The availability of climatological chlorophyll-a concentration data products from the SeaWiFS mission spanning the eight-year mission period allowed the creation of a climatological anomaly analysis function in Giovanni, the GES DISC Interactive Online Visualization and ANalysis Infrastructure. This study utilizes the Giovanni anomaly analysis function to examine mesoscale anomalies in the North Atlantic Ocean during the springtime North Atlantic Bloom. This examination indicates that areas exhibiting positive anomalies and areas exhibiting negative anomalies are coherent over significant spatial scales, with relatively abrupt boundaries between areas with positive and negative anomalies. Year-to-year variability in anomaly "intensity" can be caused by either variability in the temporal occurrence of the bloom peak or by variability in the peak chlorophyll concentration in a particular area. The study will also discuss the feasibility of combining chlorophyll anomaly analysis with other data types.

Contribution of mycosporine-like amino acids and colored dissolved and particulate matter to sea ice optical properties and ultraviolet attenuation

PubMed Central

Uusikivi, Jari; Vähätalo, Anssi V.; Granskog, Mats A.; Sommaruga, Ruben

2010-01-01

In the Baltic Sea ice, the spectral absorption coefficients for particulate matter (PM) were about two times higher at ultraviolet wavelengths than at photosynthetically available radiation (PAR) wavelengths. PM absorption spectra included significant absorption by mycosporine-like amino acids (MAAs) between 320 and 345 nm. In the surface ice layer, the concentration of MAAs (1.37 μg L−1) was similar to that of chlorophyll a, resulting in a MAAs-to-chlorophyll a ratio as high as 0.65. Ultraviolet radiation (UVR) intensity and the ratio of UVR to PAR had a strong relationship with MAAs concentration (R2 = 0.97, n = 3) in the ice. In the surface ice layer, PM and especially MAAs dominated the absorption (absorption coefficient at 325 nm: 0.73 m−1). In the columnar ice layers, colored dissolved organic matter was the most significant absorber in the UVR (< 380 nm) (absorption coefficient at 325 nm: 1.5 m−1). Our measurements and modeling of UVR and PAR in Baltic Sea ice show that organic matter, both particulate and dissolved, influences the optical properties of sea ice and strongly modifies the UVR exposure of biological communities in and under snow-free sea ice. PMID:20585592

Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L. oil plants for biodiesel

NASA Astrophysics Data System (ADS)

Gouveia-Neto, Artur S.; Silva, Elias A., Jr.; Oliveira, Ronaldo A.; Cunha, Patrícia C.; Costa, Ernande B.; Câmara, Terezinha J. R.; Willadino, Lilia G.

2011-02-01

Light-emitting-diode induced chlorophyll fluorescence analysis is employed to investigate the effect of water and salt stress upon the growth process of physicnut(jatropha curcas) grain oil plants for biofuel. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit) for a period of time of 30 days. The chlorophyll fluorescence(ChlF) ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the level of stress experienced by the jatropha plants. The ChlF technique data indicated that salinity plays a minor role in the chlorophyll concentration of leaves tissues for NaCl concentrations in the 25 to 200 mM range, and results agreed quite well with those obtained using conventional destructive spectrophotometric methods. Nevertheless, for higher NaCl concentrations a noticeable decrease in the Chl content was observed. The Chl fluorescence ratio analysis also permitted detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed sample in the first 10 days of the experiment when one compared control and nonwatered samples. The results suggest that the technique may potentially be applied as an early-warning indicator of stress caused by water deficit.

Seasonal variability of salinity, temperature, turbidity and suspended chlorophyll in the Tweed Estuary.

PubMed

Uncles, R J; Bloomer, N J; Frickers, P E; Griffiths, M L; Harris, C; Howland, R J; Morris, A W; Plummer, D H; Tappin, A D

2000-05-05

Results are presented from a campaign of measurements that were undertaken to examine seasonal variability in physical and chemical fluxes and processes within the Tweed Estuary during the period September 1996-August 1997. The study utilised monthly surveys, each of approximately 1 week duration. This article interprets a subset of the salinity, temperature, turbidity [suspended particulate matter (SPM) levels] and chlorophyll a data. Measurements discussed here were obtained throughout the estuary during high-speed transects that covered the region between the tidal river and the coastal zone. Longitudinal distributions of surface salinity depended strongly on freshwater runoff. During high runoff the surface salinity was low and the freshwater-saltwater interface (FSI) was located close to the mouth. The reverse was true at times of low runoff. Salinity stratification was generally strong. During the surveys, river runoff temperatures ranged from approximately 2 to 18 degrees C and coastal waters (approximately 33 salinity) from approximately 6 to 15 degrees C. Turbidity was low throughout the campaign (SPM < 30 mg l(-1)). Because of rapid flushing times (one or two tides), turbidity tended to mix conservatively between river and coastal waters. Higher coastal turbidity was associated with stronger wind events, and higher fluvial turbidity with spate events. Suspended chlorophyll a levels were usually low throughout the estuary (typically < 2 microg l(-1)) and showed large spatial variability. Because of the rapid flushing of the estuary, it is hypothesised that it was not possible for several algal cell divisions to occur before algae were flushed to the coastal zone. A 'bloom' occurred during the May 1997 survey, when chlorophyll a levels reached 14 microg l(-1). Higher chlorophyll a concentrations at that time occurred at very low salinities, indicating that these waters and algae were largely fluvially derived, and may have resulted from increasing springtime solar irradiation.

Phytoplankton global mapping from space with a support vector machine algorithm

NASA Astrophysics Data System (ADS)

de Boissieu, Florian; Menkes, Christophe; Dupouy, Cécile; Rodier, Martin; Bonnet, Sophie; Mangeas, Morgan; Frouin, Robert J.

2014-11-01

In recent years great progress has been made in global mapping of phytoplankton from space. Two main trends have emerged, the recognition of phytoplankton functional types (PFT) based on reflectance normalized to chlorophyll-a concentration, and the recognition of phytoplankton size class (PSC) based on the relationship between cell size and chlorophyll-a concentration. However, PFTs and PSCs are not decorrelated, and one approach can complement the other in a recognition task. In this paper, we explore the recognition of several dominant PFTs by combining reflectance anomalies, chlorophyll-a concentration and other environmental parameters, such as sea surface temperature and wind speed. Remote sensing pixels are labeled thanks to coincident in-situ pigment data from GeP&CO, NOMAD and MAREDAT datasets, covering various oceanographic environments. The recognition is made with a supervised Support Vector Machine classifier trained on the labeled pixels. This algorithm enables a non-linear separation of the classes in the input space and is especially adapted for small training datasets as available here. Moreover, it provides a class probability estimate, allowing one to enhance the robustness of the classification results through the choice of a minimum probability threshold. A greedy feature selection associated to a 10-fold cross-validation procedure is applied to select the most discriminative input features and evaluate the classification performance. The best classifiers are finally applied on daily remote sensing datasets (SeaWIFS, MODISA) and the resulting dominant PFT maps are compared with other studies. Several conclusions are drawn: (1) the feature selection highlights the weight of temperature, chlorophyll-a and wind speed variables in phytoplankton recognition; (2) the classifiers show good results and dominant PFT maps in agreement with phytoplankton distribution knowledge; (3) classification on MODISA data seems to perform better than on SeaWIFS data, (4) the probability threshold screens correctly the areas of smallest confidence such as the interclass regions.

Concentration and characterization of dissolved organic matter in the surface microlayer and subsurface water of the Bohai Sea, China

NASA Astrophysics Data System (ADS)

Chen, Yan; Yang, Gui-Peng; Wu, Guan-Wei; Gao, Xian-Chi; Xia, Qing-Yan

2013-01-01

A total of 19 sea-surface microlayer and corresponding subsurface samples collected from the Bohai Sea, China in April 2010 were analyzed for chlorophyll a, dissolved organic carbon (DOC) and its major compound classes including total dissolved carbohydrates (TDCHO, including monosaccharides, MCHO, and polysaccharides, PCHO) and total hydrolysable amino acids (THAA, including dissolved free, DFAA, and combined fraction, DCAA). The concentrations of DOC in the subsurface water ranged from 130.2 to 407.7 μM C, with an average of 225.9±75.4 μM C, while those in the surface microlayer varied between 140.1 and 330.9 μM C, with an average of 217.8±56.8 μM C. The concentrations of chlorophyll a, DOC, TDCHO and THAA in the microlayer were, respectively correlated with their subsurface water concentrations, implying that there was a strong exchange effect between the microlayer and subsurface water. The concentrations of DOC and TDCHO were negatively correlated with salinity, respectively, indicating that water mixing might play an important role in controlling the distribution of DOC and TDCHO in the water column. Major constituents of DCAA and DFAA present in the study area were glycine, alanine, glutamic acid, serine and histidine. Principal component analysis (PCA) was applied to examine the complex compositional differences that existed among the sampling sites. Our results showed that DFAA had higher mole percentages of glycine, valine and serine in the microlayer than in the subsurface water, while DCAA tended to have higher mole percentages of glutamic acid, aspartic acid, threonine, arginine, alanine, tyrosine, phenylalanine and leucine in the microlayer. The yields of TDCHO and THAA exhibited similar trends between the microlayer and subsurface water. Carbohydrate species displayed significant enrichment in the microlayer, whereas the DFAA and DCAA exhibited non-uniform enrichment in the microlayer.

Completing the Feedback Loop: The Impact of Chlorophyll Data Assimilation on the Ocean State

NASA Technical Reports Server (NTRS)

Borovikov, Anna; Keppenne, Christian; Kovach, Robin

2015-01-01

In anticipation of the integration of a full biochemical model into the next generation GMAO coupled system, an intermediate solution has been implemented to estimate the penetration depth (1Kd_PAR) of ocean radiation based on the chlorophyll concentration. The chlorophyll is modeled as a tracer with sources-sinks coming from the assimilation of MODIS chlorophyll data. Two experiments were conducted with the coupled ocean-atmosphere model. In the first, climatological values of Kpar were used. In the second, retrieved daily chlorophyll concentrations were assimilated and Kd_PAR was derived according to Morel et al (2007). No other data was assimilated to isolate the effects of the time-evolving chlorophyll field. The daily MODIS Kd_PAR product was used to validate the skill of the penetration depth estimation and the MERRA-OCEAN re-analysis was used as a benchmark to study the sensitivity of the upper ocean heat content and vertical temperature distribution to the chlorophyll input. In the experiment with daily chlorophyll data assimilation, the penetration depth was estimated more accurately, especially in the tropics. As a result, the temperature bias of the model was reduced. A notably robust albeit small (2-5 percent) improvement was found across the equatorial Pacific ocean, which is a critical region for seasonal to inter-annual prediction.

Plant abiotic stress diagnostic by laser induced chlorophyll fluorescence spectral analysis of in vivo leaf tissue of biofuel species

NASA Astrophysics Data System (ADS)

Gouveia-Neto, Artur S.; Silva, Elias A., Jr.; Costa, Ernande B.; Bueno, Luciano A.; Silva, Luciana M. H.; Granja, Manuela M. C.; Medeiros, Maria J. L.; Câmara, Terezinha J. R.; Willadino, Lilia G.

2010-02-01

Laser induced fluorescence is exploited to evaluate the effect of abiotic stresses upon the evolution and characteristics of in vivo chlorophyll emission spectra of leaves tissues of brazilian biofuel plants species(Saccharum officinarum and Jatropha curcas). The chlorophyll fluorescence spectra of 20 min predarkened intact leaves were studied employing several excitation wavelengths in the UV-VIS spectral region. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were analyzed as a function of the stress intensity and the time of illumination(Kautsky effect). The Chl fluorescence ratio Fr/FFr which is a valuable nondestructive indicator of the chlorophyll content of leaves was investigated during a period of time of 30 days. The dependence of the Chl fluorescence ratio Fr/FFr upon the intensity of the abiotic stress(salinity) was examined. The results indicated that the salinity plays a major hole in the chlorophyll concentration of leaves in both plants spieces, with a significant reduction in the chlorophyll content for NaCl concentrations in the 25 - 200 mM range. The laser induced chlorophyll fluorescence analysis allowed detection of damage caused by salinity in the early stages of the plants growing process, and can be used as an early-warning indicator of salinity stress

A new parameterization for surface ocean light attenuation in Earth System Models: assessing the impact of light absorption by colored detrital material

NASA Astrophysics Data System (ADS)

Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

2015-03-01

Light limitation can affect the distribution of biota and nutrients in the ocean. Light absorption by colored detrital material (CDM) was included in a fully coupled Earth System Model using a new parameterization for shortwave attenuation. Two model runs were conducted, with and without light attenuation by CDM. In a global average sense, greater light limitation associated with CDM increased surface chlorophyll, biomass and nutrients together. These changes can be attributed to the movement of biological productivity higher up the water column, which increased surface chlorophyll and biomass while simultaneously decreasing total biomass. Meanwhile, the reduction in biomass resulted in greater nutrient availability throughout the water column. Similar results were found on a regional scale in an analysis of the oceans by biome. In coastal regions, surface chlorophyll increased by 35% while total integrated phytoplankton biomass diminished by 18%. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by comparing the competing factors of diminished light availability and increased nutrient availability on phytoplankton growth in the upper 200 m. Overall, increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients, but changes in light limitation decoupled trends between these two variables. Understanding changes in biological productivity requires both surface and depth-resolved information. Surface trends may be minimal or of the opposite sign to depth-integrated amounts, depending on the vertical structure of phytoplankton abundance.

The Effects of Chlorophyll Assimilation on Carbon Fluxes in a Global Biogeochemical Model. [Technical Report Series on Global Modeling and Data Assimilation

NASA Technical Reports Server (NTRS)

Koster, Randal D. (Editor); Rousseaux, Cecile Severine; Gregg, Watson W.

2014-01-01

In this paper, we investigated whether the assimilation of remotely-sensed chlorophyll data can improve the estimates of air-sea carbon dioxide fluxes (FCO2). Using a global, established biogeochemical model (NASA Ocean Biogeochemical Model, NOBM) for the period 2003-2010, we found that the global FCO2 values produced in the free-run and after assimilation were within -0.6 mol C m(sup -2) y(sup -1) of the observations. The effect of satellite chlorophyll assimilation was assessed in 12 major oceanographic regions. The region with the highest bias was the North Atlantic. Here the model underestimated the fluxes by 1.4 mol C m(sup -2) y(sup -1) whereas all the other regions were within 1 mol C m(sup -2) y(sup -1) of the data. The FCO2 values were not strongly impacted by the assimilation, and the uncertainty in FCO2 was not decreased, despite the decrease in the uncertainty in chlorophyll concentration. Chlorophyll concentrations were within approximately 25% of the database in 7 out of the 12 regions, and the assimilation improved the chlorophyll concentration in the regions with the highest bias by 10-20%. These results suggest that the assimilation of chlorophyll data does not considerably improve FCO2 estimates and that other components of the carbon cycle play a role that could further improve our FCO2 estimates.

Pigments, size and distribution of Synechococcus spp. in the Black Sea

NASA Astrophysics Data System (ADS)

Uysal, Zahit

2000-03-01

Pigments, size and distribution of Phycoerythrin-containing unicellular cyanobacteria Synechococcus spp. within the euphotic zone were studied for the first time in April-May 1994 in the western and southwestern Black Sea by epifluorescence microscopy and flow-cytometry. Synechococcus was present in varying quantities at every station and depth studied. Surface spatial distribution of Synechococcus revealed that cells were much more abundant in offshore waters than near coastal regions under the direct influence of the Danube river. Minimum and maximum cell concentrations ranged between 9×10 2 and 1.45×10 5 cells/ml at the surface, between 2×10 3 and 1.23×10 5 cells/ml at the chlorophyll sub-maximum layer, and between 1.3×10 2 and 3.5×10 2 at the nitrite maximum layer. Cells at the chlorophyll sub-maximum layer (based on in-situ fluorometer readings) fluoresce brighter and longer than the ones at the surface and lower depths. Spectral properties of chromophore pigment types of total 64 clonal isolates from different depths down to the lower layer of the euphotic zone (˜60 m) in the southern Black Sea coast revealed that all have type 2 phycoerythrobilin in common, lacking in phycourobilin. In vivo fluorescence emission maxima for the phycoerythrobilin were about the same (˜578 nm) for all isolates. All isolates examined showed in vivo absorption maxima at between 435 and 442 nm and at about 681 nm due to chlorophyll- a. Based on the flow cytometer mean forward light scatter data for size distribution, it could be concluded that cells at the surface mixed layer (0-10 m) were larger in cell size than the cells at lower depths (20-60 m).

Remote sensing of chlorophyll concentrations in the northern Gulf of Mexico

NASA Technical Reports Server (NTRS)

Trees, Charles C.; El-Sayed, Sayed Z.

1986-01-01

During a 17 month period (November 1978 - March 1980), phytoplankton pigment concentrations were remotely sensed in the northern Gulf of Mexico using the Coastal Zone Color Scanner (CZCS). A total of 29 CZCS orbits were processed into pigment (chlorophyll a + phaeopigments) images and then geometrically warped to a Mercator projection. A correction factor of 1.67 was applied to the pigment concentrations to correct for the tendency of the standard fluorometric method to underestimate chlorophyll a concentrations. The spatial and temporal distributions of pigment fronts were quite variable during this time series. Constant features observed throughout the pigment imagery were the entrainment of coastal waters offshore. The most extensive entrainments occurred during intrusions of the Loop Current. For the 17 month survey, the mean HPLC-corrected pigment concentration was 3.30 + or - 1.45 mg/cu m.

A Three Year Study of Four Species of Baleen Whales Occurrence in Faial-Pico Islands of the Azores and its Relation to Satellite-derived Surface Biophysical Products

NASA Astrophysics Data System (ADS)

Olio, M.; Peres dos Santos, R.; Tepsich, P.; Martins, A. M.

2016-02-01

In this study, data on the distribution of blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), sei whales (Balaenoptera borealis) and humpback whales (Megaptera novaeangliae) in the waters around Faial and Pico islands (Azores archipelago, NE Atlantic) were collected during three years (2012 to 2014) for the months of March to July. During this period of time, we recorded 518 encounters with these species, being 73 in 2012, 86 in 2013 and 359 in 2014. Recordings were made during whale watching trips from two whale watching companies in those islands. In an attempt to understand better the different yearly occurrences, we used MODIS/AQUA-derived Sea Surface Temperature (SST) and Ocean Colour (chlorophyll a) to calculate weekly, bi-weekly, monthly, seasonal and yearly averages. Seasonal effects were removed from the data as well, to infer possible trends with time (2011 to 2014). Climatological anomalies were also calculated using MODIS data from 2003 to 2014. Results show that both years 2011 and 2012 present SST and OC negative anomalies through out the whole years. Higher chlorophyll a positive anomalies are observed during the spring of 2014. Maximum SST and chlorophyll a values ranged between 15.4 to 24.0 C and from 0.0 to 0.3 mg m-3, respectively. Sea surface tempature minimum and maxima anomalies ranged from -1.023 and 1.008 both for 2012, and -0.138 and 0.144 for chlorophyll a (for 2012 and 2014, respectively). Preliminary results suggest that phytoplankton concentration may explain the distribution of some whales species, particulary in 2014 where whale records were highest. These results are being further developed looking at mesoscale variability episodical occurrences on weekly to yearly data. Key words: baleen whales, whale watching, spatial and temporal distribution, remote sensing, mesoscale variability.

An avenue of eddies: Quantifying the biophysical properties of mesoscale eddies in the Tasman Sea

NASA Astrophysics Data System (ADS)

Everett, J. D.; Baird, M. E.; Oke, P. R.; Suthers, I. M.

2012-08-01

The Tasman Sea is unique - characterised by a strong seasonal western boundary current that breaks down into a complicated field of mesoscale eddies almost immediately after separating from the coast. Through a 16-year analysis of Tasman Sea eddies, we identify a region along the southeast Australian coast which we name ‘Eddy Avenue’ where eddies have higher sea level anomalies, faster rotation and greater sea surface temperature and chlorophyll a anomalies. The density of cyclonic and anticyclonic eddies within Eddy Avenue is 23% and 16% higher respectively than the broader Tasman Sea. We find that Eddy Avenue cyclonic and anticyclonic eddies have more strongly differentiated biological properties than those of the broader Tasman Sea, as a result of larger anticyclonic eddies formed from Coral Sea water depressing chl. a concentrations, and for coastal cyclonic eddies due to the entrainment of nutrient-rich shelf waters. Cyclonic eddies within Eddy Avenue have almost double the chlorophyll a (0.35 mg m-3) of anticyclonic eddies (0.18 mg m-3). The average chlorophyll a concentration for cyclonic eddies is 16% higher in Eddy Avenue and 28% lower for anticyclonic eddies when compared to the Tasman Sea. With a strengthening East Australian Current, the propagation of these eddies will have significant implications for heat transport and the entrainment and connectivity of plankton and larval fish populations.

Accumulation of sedimentary photosynthetic pigments characterized by pyropheophorbide a and steryl chlorin esters (SCEs) in a shallow eutrophic coastal lake (Lake Hamana, Japan)

NASA Astrophysics Data System (ADS)

Itoh, Nobuyasu; Tani, Yukinori; Soma, Yuko; Soma, Mitsuyuki

2007-01-01

We investigated the factors controlling the composition of sedimentary photosynthetic pigments in Lake Hamana (Japan), a shallow (12 m), brackish, holomictic lake, by analyzing photosynthetic pigments and the sterol composition of steryl esters of pyropheophorbide a (steryl chlorin esters, SCEs) in the water column and surface sediments. The mean annual composition of carotenoids in the water was quite different from that in the surface sediments. We evaluated the relative accumulation efficiency of individual pigments in the sediments by comparing ratios of individual pigment concentrations relative to total chlorophyll a (TChl- a) in sediment to those in the water column. The relative accumulation efficiencies decreased in the following order: lutein > diatoxanthin > β,β-carotene > zeaxanthin > β,ɛ-carotene > alloxanthin ≫ fucoxanthin. The ratio of total pyro-derivatives of chlorophyll a, formed through the grazing of algae by zooplankton, to TChl- a in the surface sediments was much higher (0.24-0.33) than that in the water column, which was less than 0.03 even in the deepest water (10 m). The summed concentration of pyropheophytin a and SCEs (TPyphe- a) showed positive and significant relationships ( r2 > 0.56, n = 7) with residual carotenoids in sediments. These results suggest that incorporation of algal pigments in fecal pellets through grazing by zooplankton enhances pigment preservation during early diagenesis at the sediment surface. Moreover, sedimentary carotenoid compositions were consistent with the sterol compositions of sedimentary SCE fractions. Selective grazing by zooplankton was thus a primary factor determining the composition of sedimentary carotenoids in this lake.

Temporal variation in photosynthetic pigments and UV-absorbing compounds in shallow populations of two Hawaiian reef corals

USGS Publications Warehouse

Kuffner, I.B.

2005-01-01

As we seek to understand the physiological mechanisms of coral bleaching, it is important to understand the background temporal variation in photosynthetic pigments and photoprotective compounds that corals exhibit. In this study, reef flat populations of two hermatypic coral species, Montipora capitata (Dana, 1846) and Porites compressa Dana, 1846, were sampled monthly in Kane'ohe Bay, Hawai'i, from January 1998 to March 1999. Surface ultraviolet radiation (UVR) was measured continually during this time period at the same location. High-performance liquid chromatography (HPLC) analysis of photosynthetic pigments and mycosporine-like amino acids (MAAs) revealed temporal changes in concentrations and proportions of these compounds in tissues of both species of coral. Chlorophyll a (chl a), chlorophyll c2 (chl c2), peridinin, and diadinoxanthin concentrations changed on a skeletal weight (M. capitata) or surface area (P. compressa) basis, significantly correlating with seasonal changes in solar input (number of days from the winter solstice). In P. compressa, diadinoxanthin increased in proportion to the total pigment pool during summer months, suggesting an up-regulation of a xanthophyll cycle. In M. capitata, the ratio of chl a: chl c2 decreased during winter months, suggesting photoacclimation to lower light levels. It is surprising that there was not a clear seasonal pattern in total MAA concentration for either species, with the exception of shinorine in P. compressa. The relative stability of MAA concentrations over the course of the year despite a pronounced seasonal trend in UVR suggests either that MAAs are not performing a photoprotective role in these species or that concentrations are kept at a threshold level in the presence of a dynamic light environment. ?? 2005 by University of Hawai'i Press All rights reserved.

Water Quality Conditions in Upper Klamath and Agency Lakes, Oregon, 2006

USGS Publications Warehouse

Lindenberg, Mary K.; Hoilman, Gene; Wood, Tamara M.

2008-01-01

The U.S. Geological Survey Upper Klamath Lake water quality monitoring program gathered information from multiparameter continuous water quality monitors, physical water samples, dissolved oxygen production and consumption experiments, and meteorological stations during the June-October 2006 field season. The 2006 study area included Agency Lake and all of Upper Klamath Lake. Seasonal patterns in water quality were similar to those observed in 2005, the first year of the monitoring program, and were closely related to bloom dynamics of the cyanobacterium (blue-green alga) Aphanizomenon flos-aquae (AFA) in the two lakes. High dissolved oxygen and pH conditions in both lakes before the bloom declined in July, which coincided with seasonal high temperatures and resulted in seasonal lows in dissolved oxygen and decreased pH. Dissolved oxygen and pH in Upper Klamath and Agency Lakes increased again after the bloom recovered. Seasonal low dissolved oxygen and decreased pH coincided with seasonal highs in ammonia and orthophosphate concentrations. Seasonal maximum daily average temperatures were higher and minimum dissolved oxygen concentrations were lower in 2006 than in 2005. Conditions potentially harmful to fish were influenced by seasonal patterns in bloom dynamics and bathymetry. Potentially harmful low dissolved oxygen and high un-ionized ammonia concentrations occurred mostly at the deepest sites in the Upper Klamath Lake during late July, coincident with a bloom decline. Potentially harmful pH conditions occurred mostly at sites outside the deepest parts of the lake in July and September, coincident with a heavy bloom. Instances of possible gas bubble formation, inferred from dissolved oxygen data, were estimated to occur frequently in shallow areas of Upper Klamath and Agency Lakes simultaneously with potentially harmful pH conditions. Comparison of the data from monitors in nearshore areas and monitors near the surface of the water column in the open waters of Upper Klamath Lake revealed few differences in water quality dynamics. Median daily temperatures were higher in nearshore areas, and dissolved oxygen concentrations were periodically higher as well during periods of high AFA bloom. Differences between the two areas in water quality conditions potentially harmful to fish were not statistically significant (p < 0.05). Chlorophyll a concentrations varied temporally and spatially throughout Upper Klamath Lake. Chlorophyll a concentrations indicated an algal bloom in late June and early July that was followed by an algae bloom decline in late July and early August and a subsequent recovery in mid-August. Sites in the deepest part of the lake, where some of the highest chlorophyll a concentrations were observed, were the same sites where the lowest dissolved oxygen concentrations and the highest un-ionized ammonia concentrations were recorded during the bloom decline, indicating cell senescence. Total phosphorus concentrations limited the initial algal bloom in late June and early July. The rate of net dissolved oxygen production (that is, production in excess of community respiration) and consumption (due to community respiration) in the lake water column as measured in light and dark bottles, respectively, ranged from 2.79 to -2.14 milligrams of oxygen per liter per hour. Net production rate generally correlated positively with chlorophyll a concentration, except episodically at a few sites where high chlorophyll a concentrations resulted in self-shading that inhibited photosynthesis. The depth of photic zone was inversely correlated with chlorophyll a concentration. Calculations of a 24-hour change in dissolved oxygen concentration indicated that oxygen-consuming processes predominated at the deep trench sites and oxygen-producing processes predominated at the shallow sites. In addition, calculations of the 24-hour change in dissolved oxygen indicate that oxygen-consuming processes in the water column di

Factors influencing the at-sea distribution of Cassin's Auklets (Ptychoramphus aleuticus) that breed in the Channel Islands, California

USGS Publications Warehouse

Adams, Josh; Takekawa, John Y.; Carter, Harry R.; Yee, Julie L.

2010-01-01

We used radiotelemetry to evaluate at-sea habitat use by Cassin's Auklets (Ptychoramphus aleuticus) that bred at Prince Island, off southern California, from 1999 through 2001. We used logistic regression to compare paired radiotelemetry (presence) with random (pseudo-absence) location-associated habitat variables derived from (1) satellite remote-sensing of sea surface temperature and chlorophyll-a concentration and (2) bathymetry. Compared with random locations within their foraging area and after controlling for distance to colony, odds ratios indicated that Cassin's Auklets with dependent young occurred in relatively shallower, warmer, and chlorophyll-rich water associated with chlorophyll fronts near the insular shelf break. These oceanographic features characterize habitats that support key euphausiid prey (e.g., Thysanoessa spinifera) and also other krill predators. Radiotelemetry combined with satellite remote-sensing of the ocean provides an alternative to vessel-based surveys for evaluating seabird foraging habitats. In the absence of information on the actual distribution, abundance, and, hence, availability of Zooplankton prey for seabirds, environmental factors can serve as proxies to help elucidate distributional patterns of seabirds at sea.

Dynamics of plankton populations in upwelling areas

NASA Technical Reports Server (NTRS)

Szekielda, K. (Principal Investigator)

1972-01-01

There are no author-identified significant results in this report. Repeated coverage over the test site along the northwest coast of Africa showed that the structure of chlorophyll distribution is much more complicated than expected from continuous recordings. ERTS-1 data showed a very fast change in the chlorophyll distribution and it seems that also the concentration changes quickly. ERTS-1 showed on some frames offshore transportation of dust from the Sahara. All frames from Channel 7 will be arranged as a montage to derive the transportation pattern of dust. This step is important in biological aspects of interpreting ERTS-1 data, because the dissolution kinetics of eolian dust particles may influence significantly the chemistry of the surface water. Since visibility and the biochemistry of the test site off Africa are influenced by the dust transport, dust collection will be included in the ground truth program. Besides chlorophyll and other hydrographical parameters, the dust load in the test area will be measured. The collection plan is discussed along with a description of the high volume air sampler and the Anderson particle sizing head sampler to be used for the dust measurements.

Phosphorus, nitrogen and chlorophyll-a are significant factors controlling ciliate communities in summer in the northern Beibu Gulf, South China Sea.

PubMed

Wang, Yibo; Zhang, Wenjing; Lin, Yuanshao; Cao, Wenqing; Zheng, Lianming; Yang, Jun

2014-01-01

Ciliates (protozoa) are ubiquitous components of plankton community and play important roles in aquatic ecosystems in regards of their abundance, biomass, diversity and energy turnover. Based on the stratified samples collected from the northern Beibu Gulf in August 2011, species composition, abundance, biomass, diversity and spatial pattern of planktonic ciliates were studied. Furthermore the main environmental factors controlling ciliate communities were determined. A total of 101 species belonging to 44 genera and 7 orders (i.e., Oligotrichida, Haptorida, Euplotida, Sessilida, Pleurostomatida, Scuticociliatida and Tintinnida) were identified. The variation of ciliate communities was significant at horizontal level, but that was not at vertical level. Based on cluster analysis, ciliate communities were divided into three main groups. Redundancy analysis (RDA) revealed that Group A, existing in the waters with higher concentration of phosphorus and nitrogen, was dominated by Tintinnidium primitivum. Group B in the waters with lower temperature and chlorophyll-a concentration, was dominated by Leegaardiella ovalis. Group C, existing in the waters with higher temperature and chlorophyll-a concentration, was dominated by large Strombidium spp. and Mesodinium rubrum. Combining multiple analytic methods, our results strongly supported that phosphorus, nitrogen and chlorophyll-a were the most significant factors affecting the ciliate communities in the northern Beibu Gulf in summer. Concentration of phosphorus and nitrogen primarily influenced ciliate biomass, implying a potential impact of eutrophication on ciliate growth. The correlation with chlorophyll-a concentration, on one hand indicate the response of ciliates to the food availability, and on the other hand, the ciliates containing chloroplasts or endosymbionts may contribute greatly to the chlorophyll-a.

S190 interpretation techniques development and application to New York State water resources. [Lake Ontario and Conesus Lake

NASA Technical Reports Server (NTRS)

Piech, K. R. (Principal Investigator); Schott, J. R.; Stewart, K. M.

1975-01-01

The author has identified the following significant results. The program has demonstrated that Skylab imagery can be utilized to regularly monitor eutrophication indices of lakes, such as chlorophyll concentration and photic zone depth. The relationship between the blue to green reflectance ratio and chlorophyll concentration was shown, along with changes in lake properties caused by chlorophyll, lignin, and humic acid using reflectance ratios and changes. A data processing technique was developed for detecting atmospheric fluctuations occurring over a large lake.

Surface Waves as Major Controls on Particle Backscattering in Southern California Coastal Waters

NASA Astrophysics Data System (ADS)

Henderikx Freitas, F.; Fields, E.; Maritorena, S.; Siegel, D.

2016-02-01

Satellite observations of particle loads and optical backscattering coefficients (bbp) in the Southern California Bight (SCB) have been thought to be driven by episodic inputs from storm runoff. Here we show however that surface waves have a larger role in controlling remotely sensed bbp values than previously considered. More than 14 years of 2-km resolution SeaWiFS, MODIS and MERIS satellite imagery spectrally-merged with the Garver-Siegel-Maritorena bio-optical model were used to assess the relative importance of terrestrial runoff and surface wave forcings in determining changes in particle load in the SCB. The space-time distributions of particle backscattering at 443nm and chlorophyll concentration estimates from the model were analyzed using Empirical Orthogonal Function analysis, and patterns were compared with several environmental variables. While offshore values of bbp are tightly related to chlorophyll concentrations, as expected for productive Case-1 waters, values of bbp in a 10km band near the coast are primarily modulated by surface waves. The relationship with waves holds throughout all seasons and is most apparent around the 40m isobath, but extends offshore until about 100m in depth. Riverine inputs are associated with elevated bbp near the coast mostly during the larger El Nino events of 1997/1998 and 2005. These findings are consistent with bio-optical glider and field observations from the Santa Barbara Channel taken as part of the Santa Barbara Coastal Long-Term Ecological Research and Plumes and Blooms programs. The implication of surface waves determining bbp variability beyond the surf zone has large consequences for the life cycle of many marine organisms, as well as for the interpretation of remote sensing signals near the coast.

Effect of an acid mine drainage effluent on phytoplankton biomass and primary production at Britannia Beach, Howe Sound, British Columbia.

PubMed

Levings, C D; Varela, D E; Mehlenbacher, N M; Barry, K L; Piercey, G E; Guo, M; Harrison, P J

2005-12-01

We investigated the effect of acid mine drainage (AMD) from an abandoned copper mine at Britannia Beach (Howe Sound, BC, Canada) on primary productivity and chlorophyll a levels in the receiving waters of Howe Sound before, during, and after freshet from the Squamish River. Elevated concentrations of copper (integrated average through the water column >0.050 mgl(-1)) in nearshore waters indicated that under some conditions a small gyre near the mouth of Britannia Creek may have retained the AMD from Britannia Creek and from a 30-m deep water outfall close to shore. Regression and correlation analyses indicated that copper negatively affected primary productivity during April (pre-freshet) and November (post-freshet). Negative effects of copper on primary productivity were not supported statistically for July (freshet), possibly because of additional effects such as turbidity from the Squamish River. Depth-integrated average and surface chlorophyll a were correlated to copper concentrations in April. During this short study we demonstrated that copper concentrations from the AMD discharge can negatively affect both primary productivity and the standing stock of primary producers in Howe Sound.

Spatial extent and dissipation of the deep chlorophyll layer in Lake Ontario during the Lake Ontario lower foodweb assessment, 2003 and 2008

USGS Publications Warehouse

Watkins, J. M.; Weidel, Brian M.; Rudstam, L. G.; Holek, K. T.

2014-01-01

Increasing water clarity in Lake Ontario has led to a vertical redistribution of phytoplankton and an increased importance of the deep chlorophyll layer in overall primary productivity. We used in situ fluorometer profiles collected in lakewide surveys of Lake Ontario in 2008 to assess the spatial extent and intensity of the deep chlorophyll layer. In situ fluorometer data were corrected with extracted chlorophyll data using paired samples from Lake Ontario collected in August 2008. The deep chlorophyll layer was present offshore during the stratified conditions of late July 2008 with maximum values from 4-13 μg l-1 corrected chlorophyll a at 10 to 17 m depth within the metalimnion. Deep chlorophyll layer was closely associated with the base of the thermocline and a subsurface maximum of dissolved oxygen, indicating the feature's importance as a growth and productivity maximum. Crucial to the deep chlorophyll layer formation, the photic zone extended deeper than the surface mixed layer in mid-summer. The layer extended through most of the offshore in July 2008, but was not present in the easternmost transect that had a deeper surface mixed layer. By early September 2008, the lakewide deep chlorophyll layer had dissipated. A similar formation and dissipation was observed in the lakewide survey of Lake Ontario in 2003.

Energy transfer between surface-immobilized light-harvesting chlorophyll a/b complex (LHCII) studied by surface plasmon field-enhanced fluorescence spectroscopy (SPFS).

PubMed

Lauterbach, Rolf; Liu, Jing; Knoll, Wolfgang; Paulsen, Harald

2010-11-16

The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCII potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCII to be immobilized on a solid surface. In a previous study we showed the immobilization of recombinant LHCII on functionalized gold surfaces via a 6-histidine tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Förster energy transfer between immobilized LHCII on a functionalized surface have been analyzed by surface plasmon field-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCII.

The use of near-infrared photography for biodegradable pollution monitoring of tidal rivers

NASA Technical Reports Server (NTRS)

Bressette, W. E.; Lear, D. E., Jr.

1973-01-01

On October 2, 1972, a pattern of chlorophyll a containing phytoplankton (algae) was detected from 3-km altitude in a series of near-infrared photographs of the Potomac River 'Salt Wedge Area.' Densitometer traces over the film images, related to in situ measurements of chlorophyll a concentrations that varied from 4 to more than 3000 micrograms/liter, revealed a phytoplankton 'bloom' threshold in the near infrared between the concentration of 34 and 51 micrograms/liter. The photography also revealed bottom features through two meters of water and made it possible to integrate chlorophyll a concentrations over a 16 sq km area to demonstrate this remote sensing technique for biodegradable pollution monitoring.

Are the spring and fall blooms on the Scotian Shelf related to short-term physical events?

NASA Astrophysics Data System (ADS)

Greenan, B. J. W.; Petrie, B. D.; Harrison, W. G.; Oakey, N. S.

2004-03-01

Physical, chemical and biological data from the Scotian Shelf indicate that short-term physical events affect the dynamics of spring and fall blooms. This is based on results from a three-week mooring deployment measuring currents, temperature, salinity and fluorescence in October 2000, combined with biweekly sampling of temperature, salinity, nutrients and chlorophyll throughout the year at this mooring site. A wind-driven upwelling event in mid-October shows temperature, salinity and density iso-surfaces rising by approximately 20 m. During this event, a bloom with peak chlorophyll concentrations of about 2.5 mg m -3 began as nutrients are brought into the upper part of the water column. Gradient Richardson Numbers ( Ri), a proxy for vertical mixing, are estimated for the mooring period in 2 m vertical bins using SeaHorse CTD data and nearby ADCP current measurements. These data indicate that vertical mixing may have played a complementary role to the upwelling in bringing nutrients into the euphotic zone. A trend of decreasing Ri in the ocean mixed layer with increasing surface wind stress is suggested. It appears that this short-term physical event is a primary factor in initiating the fall bloom on the inner Scotian Shelf in 2000. In April of that year, the termination of the spring bloom coincided with a downwelling event suggesting that it played a role in determining the duration of the bloom. SeaWiFS ocean color satellite provided a spatial context for chlorophyll observations, however, the lack of temporal resolution due to poor atmospheric conditions means that these data provide limited information on short-term chlorophyll variability.

Spatio-Temporal Distribution of Particulate and Dissolved Organic Matter in the Mississippi River Bight From Optical Measurements

NASA Technical Reports Server (NTRS)

DSa, E. J.; Miller, R. L.; DelCastillo, C.

2003-01-01

The Mississippi River Bight is a highly dynamic region influenced by the seasonally variable outflow from the Mississippi River. In an effort to characterize the distribution of particulate and dissolved organic matter in the region, we conducted a two-year field program in the spring and fall (high and low flow river discharge) of 2000 and 2002. We collected a comprehensive set of bio-optical measurements consisting of vertical profiles (absorption, scattering, chlorophyll fluorescence and radiometry) and discrete measurements (pigment concentrations, particulate and CDOM absorption) that enabled us to obtain better insight into the seasonal and spatial variability of some important biogeochemical parameters. Our field measurements generally showed higher phytoplankton clorophyll concentrations in the plume waters (associated with lower surface salinities) and confirmed the high biological activity abserved in other studies. The seasonal flow of river discharge and advective currents due to wind forcing exerted a strong influence on the biological and optical properties of the region. An examination of absorption at 440 nm by the algal and non-algal fraction of the particulate pool and of CDOM revealed that at nearshore stations, contributions by the non-algal particles were high (about 40%) and decresed with increasing salinities. While CDOM absorption exhibited conservative mixing, its relative contribution to the total absorption was variable. Surface waters at most stations had lower salinities that generalliy increased with dept. Particulate matter and CDOM also decreased with depth as evidenced by absorption and scattering measurements. Good correlations in surface waters between concentrations of particulate and dissolved matter, the inherent optical properties of absorption and ackscattering and remote sensing reflectance values has allowed the development of robust empirical algorithms for phytoplankton chlorophyll and CDOM absorption.

Intraseasonal flow and its impact on the chlorophyll-a concentration in the Sunda Strait and its vicinity

NASA Astrophysics Data System (ADS)

Xu, Tengfei; Li, Shujiang; Hamzah, Faisal; Setiawan, Agus; Susanto, R. Dwi; Cao, Guojiao; Wei, Zexun

2018-06-01

Sunda Strait is the outflow strait of the South China Sea branch of the Pacific to Indian Ocean Throughflow. The annual mean volume transport through the Sunda Strait is around 0.25 Sv from the Java Sea to the eastern Indian Ocean, only 2.5% of the IndonesianThroughflow, and thus has been ignored by previous investigations. However, the Nutrient concentrations in the Sunda Strait and its vicinity are found highly related to the water transport through the Sunda Strait. Particularly, our observation shows significant intraseasonal variability (ISV) of currents at period around 25-45 days in the Sunda Strait. Both remote and local wind forcing contribute to the ISVs in the Sunda Strait. The intraseasonal oscillation of sea surface wind in the central Indian Ocean drives upwelling/downwelling equatorial Kelvin waves to propagate along the equator and subsequently along the Sumatra-Java coasts, resulting in negative/positive sea level anomalies in the south of the Sunda Strait. The local intraseasonal sea surface wind anomalies also tend to induce negative/positive sea level anomalies in the south of the Sunda Strait by offshore/onshore Ekman transport while there are upwelling/downwelling events. The ensuring sea level gradient associated with the sea level anomalies in the south of the Sunda Strait induces intraseasonal outflow (from Indian Ocean to Java Sea) and inflow (from Java Sea to Indian Ocean) through the strait. Analyses also show that the chlorophyll-a concentrations in the south of the Sunda Strait are lower/higher during the inflow/outflow period of the ISV events in March through May. The mechanism attributes to both the nutrient-rich water transported by the intraseasonal flow in the Sunda Strait and by the upwelling and Ekman transport driven by the local sea surface wind anomalies.

An assessment of phytoplankton primary productivity in the Arctic Ocean from satellite ocean color/in situ chlorophyll‐a based models

PubMed Central

Matrai, Patricia A.; Friedrichs, Marjorie A. M.; Saba, Vincent S.; Antoine, David; Ardyna, Mathieu; Asanuma, Ichio; Babin, Marcel; Bélanger, Simon; Benoît‐Gagné, Maxime; Devred, Emmanuel; Fernández‐Méndez, Mar; Gentili, Bernard; Hirawake, Toru; Kang, Sung‐Ho; Kameda, Takahiko; Katlein, Christian; Lee, Sang H.; Lee, Zhongping; Mélin, Frédéric; Scardi, Michele; Smyth, Tim J.; Tang, Shilin; Turpie, Kevin R.; Waters, Kirk J.; Westberry, Toby K.

2015-01-01

Abstract We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The models were provided with two sources each of surface chlorophyll‐a concentration (chlorophyll), photosynthetically available radiation (PAR), sea surface temperature (SST), and mixed‐layer depth (MLD). The models were most sensitive to uncertainties in surface chlorophyll, generally performing better with in situ chlorophyll than with satellite‐derived values. They were much less sensitive to uncertainties in PAR, SST, and MLD, possibly due to relatively narrow ranges of input data and/or relatively little difference between input data sources. Regardless of type or complexity, most of the models were not able to fully reproduce the variability of in situ NPP, whereas some of them exhibited almost no bias (i.e., reproduced the mean of in situ NPP). The models performed relatively well in low‐productivity seasons as well as in sea ice‐covered/deep‐water regions. Depth‐resolved models correlated more with in situ NPP than other model types, but had a greater tendency to overestimate mean NPP whereas absorption‐based models exhibited the lowest bias associated with weaker correlation. The models performed better when a subsurface chlorophyll‐a maximum (SCM) was absent. As a group, the models overestimated mean NPP, however this was partly offset by some models underestimating NPP when a SCM was present. Our study suggests that NPP models need to be carefully tuned for the Arctic Ocean because most of the models performing relatively well were those that used Arctic‐relevant parameters. PMID:27668139

On the relationship between satellite-retrieved surface temperature fronts and chlorophyll a in the western South Atlantic

NASA Astrophysics Data System (ADS)

Saraceno, Martin; Provost, Christine; Piola, Alberto R.

2005-11-01

The time-space distribution of chlorophyll a in the southwestern Atlantic is examined using 6 years (1998-2003) of sea surface color images from Sea-viewing Wide Field of View Sensor (SeaWiFS). Chlorophyll a (chl a) distribution is confronted with sea surface temperature (SST) fronts retrieved from satellite imagery. Histogram analysis of the color, SST, and SST gradient data sets provides a simple procedure for pixel classification from which eight biophysical regions in the SWA are identified, including three new regions with regard to Longhurst (1998) work: Patagonian Shelf Break (PSB), Brazil Current Overshoot, and Zapiola Rise region. In the PSB region, coastal-trapped waves are suggested as a possible mechanism leading to the intraseasonal frequencies observed in SST and chl a. Mesoscale activity associated with the Brazil Current Front and, in particular, eddies drifting southward is probably responsible for the high chl a values observed throughout the Brazil Current Overshoot region. The Zapiola Rise is characterized by a local minimum in SST gradient magnitudes and shows chl a maximum values in February, 3 months later than the austral spring bloom of the surroundings. Significant interannual variability is present in the color imagery. In the PSB, springs and summers with high chl a concentrations seem associated with stronger local northerly wind speed, and possible mechanisms are discussed. Finally, the Brazil-Malvinas front is detected using both SST gradient and SeaWiFS images. The time-averaged position of the front at 54.2°W is estimated at 38.9°S and its alongshore migration of about 300 km.

Bio-physical changes in the coastal ocean triggered by typhoon: A case of Typhoon Meari in summer 2011

NASA Astrophysics Data System (ADS)

Wu, Xiao; Wang, Houjie; Bi, Naishuang; Song, Zhenjie; Zang, Zhengchen; Kineke, Gail C.

2016-12-01

Based on the combination of synchronous satellite and in-situ observations, we here, for the first time, provide the compelling evidence of bio-physical response of coastal environment in the Bohai Sea (China) to the passage of Typhoon Meari over the northern Yellow Sea on June 26, 2011. Strong sustained winds induced a tongue-like intrusion of cool water from the northern Yellow Sea into the Bohai Sea, resulting in significant surface cooling and an anomalous increase in sea surface height along the coast of the western Bohai Sea. This, in return, produced downwelling and transport of the warm and nutrient-rich coastal water from the western coast to the central Bohai Sea, as driven by the barotropic pressure gradient force. In-situ observational data confirmed the cooling of both surface and bottom layers with salinity increase; however, the measured temperature increase by 2-3 °C, concomitant salinity decrease by 0.3 PSU and two-fold increase in chlorophyll-a in the middle layers suggested an influence from coastal downwelling. Ekman transport and typhoon-enhanced mixing redistributed the nutrients and thus resulted in higher chlorophyll-a concentrations in the upper layers.

Relationship between photosynthetic pigments and chlorophyll fluorescence in soybean under varying phosphorus nutrition at ambient and elevated CO2

USDA-ARS?s Scientific Manuscript database

Photosynthetic pigments such as chlorophyll (Chl) a, Chl b and carotenoids concentration, and chlorophyll fluorescence (CF) have widely been used as indicators of stress and photosynthetic performance in plants. Although photosynthetic pigments and CF are partly interdependent due to absorption and ...

Culture of a high-chlorophyll-producing and halotolerant Chlorella vulgaris.

PubMed

Nakanishi, Koichi; Deuchi, Keiji

2014-05-01

In order to increase the value of freshwater algae as raw ingredients for health foods and feed for seawater-based farmed fish, we sought to breed high-chlorophyll halotolerant Chlorella with the objective of generating strains with both high chlorophyll concentrations (≥ 5%) and halotolerance (up to 1% NaCl). We used the Chlorella vulgaris K strain in our research institute culture collection and induced mutations with UV irradiation and acriflavine which is known to effect mutations of mitochondrial DNA that are associated with chlorophyll production. Screenings were conducted on seawater-based "For Chlorella spp." (FC) agar medium, and dark-green-colored colonies were visually selected by macroscopic inspection. We obtained a high-chlorophyll halotolerant strain (designated C. vulgaris M-207A7) that had a chlorophyll concentration of 6.7% (d.m.), a level at least three-fold higher than that of K strain. This isolate also exhibited a greater survival rate in seawater that of K strain. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Optimizing the bio-optical algorithm for estimating chlorophyll-a and phycocyanin concentrations in inland waters in Korea

USDA-ARS?s Scientific Manuscript database

Several bio-optical algorithms were developed to estimate the chlorophyll-a (Chl-a) and phycocyanin (PC) concentrations in inland waters. This study aimed at identifying the influence of the algorithm parameters and wavelength bands on output variables and searching optimal parameter values. The opt...

Limits of Active Laser Triangulation as an Instrument for High Precision Plant Imaging

PubMed Central

Paulus, Stefan; Eichert, Thomas; Goldbach, Heiner E.; Kuhlmann, Heiner

2014-01-01

Laser scanning is a non-invasive method for collecting and parameterizing 3D data of well reflecting objects. These systems have been used for 3D imaging of plant growth and structure analysis. A prerequisite is that the recorded signals originate from the true plant surface. In this paper we studied the effects of species, leaf chlorophyll content and sensor settings on the suitability and accuracy of a commercial 660 nm active laser triangulation scanning device. We found that surface images of Ficus benjamina leaves were inaccurate at low chlorophyll concentrations and a long sensor exposure time. Imaging of the rough waxy leaf surface of leek (Allium porrum) was possible using very low exposure times, whereas at higher exposure times penetration and multiple refraction prevented the correct imaging of the surface. A comparison of scans with varying exposure time enabled the target-oriented analysis to identify chlorotic, necrotic and healthy leaf areas or mildew infestations. We found plant properties and sensor settings to have a strong influence on the accuracy of measurements. These interactions have to be further elucidated before laser imaging of plants is possible with the high accuracy required for e.g., the observation of plant growth or reactions to water stress. PMID:24504106

Surface layer and bloom dynamics observed with the Prince William Sound Autonomous Profiler

NASA Astrophysics Data System (ADS)

Campbell, R. W.

2016-02-01

As part of a recent long term monitoring effort, deployments of a WETLabs Autonomous Moored Profiler (AMP) began Prince William Sound (PWS) in 2013. The PWS AMP consists of a positively buoyant instrument frame, with a winch and associated electronics that profiles the frame from a park depth (usually 55 m) to the surface by releasing and retrieving a thin UHMWPE tether; it generally conducts a daily cast and measures temperature, salinity, chlorophyll-a fluorescence, turbidity, and oxygen and nitrate concentrations. Upward and downward looking ADCPs are mounted on a float below the profiler, and an in situ plankton imager is in development and will be installed in 2016. Autonomous profilers are a relatively new technology, and early deployments experienced a number of failures from which valuable lessons may be learned. Nevertheless, an unprecedented time series of the seasonal biogeochemical procession in the surface waters coastal Gulf of Alaska was collected in 2014 and 2015. The northern Gulf of Alaska has experienced a widespread warm anomaly since early 2014, and surface layer temperature anomalies in PWS were strongly positive during winter 2014. The spring bloom observed by the profiler began 2-3 weeks earlier than average, with surface nitrate depleted by late April. Although surface temperatures were still above average in 2015, bloom timing was much later, with a short vigorous bloom in late April and a subsurface bloom in late May that coincided with significant nitrate drawdown. As well as the vernal blooms, wind-driven upwelling events lead to several small productivity pulses that were evident in changes in nitrate and oxygen concentrations, and chlorophyll-a fluorescence. As well as providing a mechanistic understanding of surface layer biogeochemistry, high frequency observations such as these put historical observations in context, and provide new insights into the scales of variability in the annual cycles of the surface ocean in the North Pacific.

Frontal dynamics boost primary production in the summer stratified Mediterranean sea

NASA Astrophysics Data System (ADS)

Olita, Antonio; Capet, Arthur; Claret, Mariona; Mahadevan, Amala; Poulain, Pierre Marie; Ribotti, Alberto; Ruiz, Simón; Tintoré, Joaquín; Tovar-Sánchez, Antonio; Pascual, Ananda

2017-06-01

Bio-physical glider measurements from a unique process-oriented experiment in the Eastern Alboran Sea (AlborEx) allowed us to observe the distribution of the deep chlorophyll maximum (DCM) across an intense density front, with a resolution (˜ 400 m) suitable for investigating sub-mesoscale dynamics. This front, at the interface between Atlantic and Mediterranean waters, had a sharp density gradient (Δ ρ ˜ 1 kg/m3 in ˜ 10 km) and showed imprints of (sub-)mesoscale phenomena on tracer distributions. Specifically, the chlorophyll-a concentration within the DCM showed a disrupted pattern along isopycnal surfaces, with patches bearing a relationship to the stratification (buoyancy frequency) at depths between 30 and 60 m. In order to estimate the primary production (PP) rate within the chlorophyll patches observed at the sub-surface, we applied the Morel and Andrè (J Geophys Res 96:685-698 1991) bio-optical model using the photosynthetic active radiation (PAR) from Argo profiles collected simultaneously with glider data. The highest production was located concurrently with domed isopycnals on the fresh side of the front, suggestive that (sub-)mesoscale upwelling is carrying phytoplankton patches from less to more illuminated levels, with a contemporaneous delivering of nutrients. Integrated estimations of PP (1.3 g C m-2d-1) along the glider path are two to four times larger than the estimations obtained from satellite-based algorithms, i.e., derived from the 8-day composite fields extracted over the glider trip path. Despite the differences in spatial and temporal sampling between instruments, the differences in PP estimations are mainly due to the inability of the satellite to measure DCM patches responsible for the high production. The deepest (depth > 60 m) chlorophyll patches are almost unproductive and probably transported passively (subducted) from upper productive layers. Finally, the relationship between primary production and oxygen is also investigated. The logarithm of the primary production in the DCM interior (chlorophyll (Chl) > 0.5 mg/m3) shows a linear negative relationship with the apparent oxygen utilization, confirming that high chlorophyll patches are productive. The slope of this relationship is different for Atlantic, mixed interface waters and Mediterranean waters, suggesting the presence of differences in planktonic communities (whether physiological, population, or community level should be object of further investigation) on the different sides of the front. In addition, the ratio of optical backscatter to Chl is high within the intermediate (mixed) waters, which is suggestive of large phytoplankton cells, and lower within the core of the Atlantic and Mediterranean waters. These observations highlight the relevance of fronts in triggering primary production at DCM level and shaping the characteristic patchiness of the pelagic domain. This gains further relevance considering the inadequacy of optical satellite sensors to observe DCM concentrations at such fine scales.

Comparing Measures of Estuarine Ecosystem Production in a ...

EPA Pesticide Factsheets

Anthropogenic nutrient enrichments and concerted efforts at nutrient reductions, compounded with the influences of climate change, are likely changing the net ecosystem production (NEP) of our coastal systems. To quantify these changes, scientists monitor a range of physical, chemical, and biological parameters sampled at various frequencies. Water column chlorophyll concentrations are arguably the most commonly used indicator of net phytoplankton production, as well as a coarse indicator of NEP. We compared parameters that estimate production, including chlorophyll, across an experimental nutrient gradient and in situ in both well-mixed and stratified estuarine environments. Data from an experiment conducted in the early 1980s in mesocosms designed to replicate a well-mixed mid-Narragansett Bay (Rhode Island) water column were used to correlate changes in chlorophyll concentrations, pH, dissolved oxygen (O2), dissolved inorganic nitrogen, phosphate, and silicate concentrations, cell counts, and 14C carbon uptake measurements across a range of nutrient enrichments. The pH, O2, nutrient, and cell count measurements reflected seasonal cycles of spring blooms followed by late summer/early fall respiration periods across nutrient enrichments. Chlorophyll concentrations were more variable and rates of 14C productivity were inconsistent with observed trends in nutrient concentrations, pH, and O2 concentrations. Similar comparisons were made using data from a well-mixe

Water Raman normalization of airborne laser fluorosensor measurements - A computer model study

NASA Technical Reports Server (NTRS)

Poole, L. R.; Esaias, W. E.

1982-01-01

The technique for normalizing airborne lidar measurements of chlorophyll fluoresence by the water Raman scattering signal is investigated for laser-excitation wavelengths of 480 and 532 nm using a semianalytic Monte Carlo methodology (SALMON). The signal-integration depth for chlorophyll fluorescence Z(90,F), is found to be insensitive to excitation wavelength and ranges from a maximum of 4.5 m in clearest waters to less than 1 m at a chlorophyll concentration of 20 microgram/liter. For excitation at 532 nm, the signal-integration depth for Raman scattering, Z(90,R), is comparable to Z(90,F). For excitation at 480 nm, Z(90,R) is four times as large as Z(90,F) in clearest waters but nearly equivalent at chlorophyll concentrations greater than 2-3 microgram/liter. Absolute signal levels are stronger with excitation at 480 nm than with excitation at 532 nm, but this advantage must be weighed against potential ambiguities resulting from different integration depths for the fluorescence and Raman scattering signals in clearer waters. To the precision of the simulations, Raman normalization produces effectively linear response to chlorophyll concentration for both excitation wavelengths.

The dynamics of suspended particulate matter (SPM) and chlorophyll-a from intratidal to annual time scales in a coastal turbidity maximum

NASA Astrophysics Data System (ADS)

van der Hout, C. M.; Witbaard, R.; Bergman, M. J. N.; Duineveld, G. C. A.; Rozemeijer, M. J. C.; Gerkema, T.

2017-09-01

The analysis of 1.8 years of data gives an understanding of the response to varying forcing of suspended particulate matter (SPM) and chlorophyll-a (CHL-a) in a coastal turbidity maximum zone (TMZ). Both temporal and vertical concentration variations in the near-bed layer (0-2 m) in the shallow (11 m deep) coastal zone at 1 km off the Dutch coast are shown. Temporal variations in the concentration of both parameters are found on tidal and seasonal scales, and a marked response to episodic events (e.g. storms). The seasonal cycle in the near-bed CHL-a concentration is determined by the spring bloom. The role of the wave climate as the primary forcing in the SPM seasonal cycle is discussed. The tidal current provides a background signal, generated predominantly by local resuspension and settling and a minor role is for advection in the cross-shore and the alongshore direction. We tested the logarithmic Rouse profile to the vertical profiles of both the SPM and the CHL-a data, with respectively 84% and only 2% success. The resulting large percentage of low Rouse numbers for the SPM profiles suggest a mixed suspension is dominant in the TMZ, i.e. surface SPM concentrations are in the same order of magnitude as near-bed concentrations.

A long-term monitoring study of chlorophyll, microbial contaminants, and pesticides in a coastal residential stormwater pond and its adjacent tidal creek.

PubMed

DeLorenzo, Marie E; Thompson, Brian; Cooper, Emily; Moore, Janet; Fulton, Michael H

2012-01-01

Stormwater ponds are commonly used in residential and commercial areas to control flooding. The accumulation of urban contaminants in stormwater ponds can lead to water-quality problems including nutrient enrichment, chemical contamination, and bacterial contamination. This study presents 5 years of monitoring data assessing water quality of a residential subdivision pond and adjacent tidal creek in coastal South Carolina, USA. The stormwater pond is eutrophic, as described by elevated concentrations of chlorophyll and phosphorus, and experiences periodic cyanobacterial blooms. A maximum monthly average chlorophyll concentration of 318.75 μg/L was measured in the stormwater pond and 227.63 μg/L in the tidal creek. Fecal coliform bacteria (FCB) levels were measured in both the pond and the tidal creek that exceeded health and safety standards for safe recreational use. A maximum monthly average FCB level of 1,247 CFU/100 mL was measured in the stormwater pond and 12,850 CFU/100 mL in the tidal creek. In addition, the presence of antibiotic resistant bacteria and pathogenic bacteria were detected. Low concentrations of herbicides (atrazine and 2,4-D: ), a fungicide (chlorothalonil), and insecticides (pyrethroids and imidacloprid) were measured. Seasonal trends were identified, with the winter months having the lowest concentrations of chlorophyll and FCB. Statistical differences between the stormwater pond and the tidal creek were also noted within seasons. The tidal creek had higher FCB levels than the stormwater pond in the spring and summer, whereas the stormwater pond had higher chlorophyll levels than the tidal creek in the summer and fall seasons. Chlorophyll and FCB levels in the stormwater pond were significantly correlated with monthly average temperature and total rainfall. Pesticide concentrations were also significantly correlated with temperature and rainfall. Pesticide concentrations in the stormwater pond were significantly correlated with pesticide concentrations in the adjacent tidal creek. Chlorophyll and FCB levels in the tidal creek, however, were not significantly correlated with levels in the pond. While stormwater ponds are beneficial in controlling flooding, they may pose environmental and human health risks due to biological and chemical contamination. Management to reduce residential runoff may improve water quality in coastal stormwater ponds and their adjacent estuarine ecosystems.

Estimating ocean production from satellite-derived chlorophyll - Insights from the EASTROPAC data set

NASA Technical Reports Server (NTRS)

Eppley, R. W.; Stewart, E.; Abbott, M. R.; Owen, R. W.

1985-01-01

The EASTROPAC expedition took place in 1967-68 in the eastern tropical Pacific Ocean. Primary production was related to near-surface chlorophyll in these data. Much of the variability in the relation was due to the light-history of the phytoplankton and its photoadaptive state. This was due to changes in the depth of mixing of the surface waters more than changes in insolation. Accurate estimates of production from satellite chlorophyll measurements may require knowledge of the temporal and spatial variation in mixing of this region.

The effects of lead stress on photosynthetic function and chloroplast ultrastructure of Robinia pseudoacacia seedlings.

PubMed

Zhou, Jian; Jiang, Zeping; Ma, Jie; Yang, Lifeng; Wei, Yuan

2017-04-01

In this experiment, the effects of different lead (Pb) concentrations (0, 200, 600, 1000, 1400 mg kg -1 ) on photosynthesis and chlorophyll fluorescence in Robinia pseudoacacia seedlings were examined. As Pb concentration increased, chlorophyll a, chlorophyll b, total chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance (g s ), and mesophyll intercellular carbon dioxide concentration were gradually reduced. Maximal photochemical efficiency, photochemical quenching, and quantum yield also decreased. However, the initial fluorescence and nonphotochemical quenching gradually increased. Chloroplasts swelled owing to local plasmolysis and lost most of their starch content, and their thylakoid lamellae gradually became disordered and loosely packed. When the chloroplast envelope was lost under high Pb stress (≥1000 mg kg -1 ), lipid globules were released into the surrounding mesophyll cell. Multiple regression analysis showed that g s and inactivity of the PSII reaction center had the greatest effect on photosynthetic function, whereas inhibition of electron transport had minimal effects on black locust seedlings under Pb stress.

CHANGES IN CHLOROPHYLL A FLUORENSCENCE AND PIGMENT RATIOS DURING DIFFERENT GROWTH PHASES OF A UNICELLULAR MARINE CHEATOSEROS (BACILLARIOPHYCEAE) IN BATCH CULTURE

EPA Science Inventory

Photosystem II reaction centers per cell decreased as the cultures began to decline. The degree of inactivation increased daily as the cell numbers continued to decrease. The concentration of chlorophyll a per cell and the ratio of the major accessory pigments to chlorophyll a (e...

Remote sensing of ocean color and detection of chlorophyll content

NASA Technical Reports Server (NTRS)

Deschamps, P. Y.; Lecompte, P.; Viollier, M.

1977-01-01

The chlorophyll enrichment of the water in an equatorial upwelling was surveyed and described with the aid of a radiometer specially designed for the airborne measurement of ocean color. A relation is proposed between airborne measurement of difference of albedos at two wavelengths in the blue and green, and the concentration of chlorophyll in the ocean.

Simultaneous measurement of chlorophyll and astaxanthin in Haematococcus pluvialis cells by first-order derivative ultraviolet-visible spectrophotometry.

PubMed

Lababpour, Abdolmajid; Lee, Choul-Gyun

2006-02-01

A first-order derivative spectrophotometric method has been developed for the simultaneous measurement of chlorophyll and astaxanthin concentrations in Haematococcus pluvialis cells. Acetone was selected for the extraction of pigments because of its good sensitivity and low toxicity compared with other organic solvents tested; the tested solvents included acetone, methanol, hexane, chloroform, n-propanol, and acetonitrile. A first-order derivative spectrophotometric method was used to eliminate the effects of the overlaping of the chlorophyll and astaxanthin peaks. The linear ranges in 1D evaluation were from 0.50 to 20.0 microg x ml(-1) for chlorophyll and from 1.00 to 12.0 microg x ml(-1) for astaxanthin. The limits of detection of the analytical procedure were found to be 0.35 microg x ml(-1) for chlorophyll and 0.25 microg x ml(-1) for astaxanthin. The relative standard deviations for the determination of 7.0 microg x ml(-1) chlorophyll and 5.0 microg x ml(-1) astaxanthin were 1.2% and 1.1%, respectively. The procedure was found to be simple, rapid, and reliable. This method was successfully applied to the determination of chlorophyll and astaxanthin concentrations in H. pluvialis cells. A good agreement was achieved between the results obtained by the proposed method and HPLC method.

A new method for fast extraction and determination of chlorophylls in natural water.

PubMed

Qiu, Nianwei; Wang, Xiushun; Zhou, Feng

2018-01-26

Algae collection and chlorophyll extraction are two troublesome steps in the traditional methods used for the determination of chlorophyll concentration in natural water. A new method was established in this study for fast collection and extraction of chlorophyll. Based on our results, the optimum centrifugation condition for collecting algae was determined as: 5000 g for 15 min at 4 °C, and the optimum dilution ratio of dimethyl sulfoxide: 90% acetone was 1:4. The specific steps were as follows: the algae in water samples were collected by centrifugation at 5000 g at 4 °C for 15 min. The precipitated algae were suspended with 2 mL DMSO. Then the sample was transferred to a 15 mL centrifuge tube, and the tube was incubated at 65 °C for 1-2 h in the dark until the sample turned white. After cooling, the chlorophyll extract was diluted with 8 mL 90% acetone, before centrifugation at 5000 g for 5 min. The absorbance values of the supernatants at 750, 664, 647 and 630 nm were used for the calculation of chlorophyll concentrations by the trichromatic equations. This new method saved the filter cost, simplified the extraction process, improved the algae acquisition efficiency, and accelerated the chlorophyll extraction rate.

A study of marine luminescence signatures, part 1

NASA Technical Reports Server (NTRS)

Hornig, A. W.; Eastwood, D.

1973-01-01

Fluorescent excitation and emission spectral data on chlorophyll and Gelbstoff in natural sea waters from the Atlantic, Gulf, and Pacific coasts show that algae particulates are totally absorbing over much of the near ultraviolet and visible spectra and act approximately as quantum counters; plant pigments absorb energy and transfer a large portion to chlorophyll where some fraction is emitted as chlorophyll fluorescence. Gelbstoff data do not exhibit quantum counter action because of their low concentration. It is concluded that luminescence data of natural sea waters are useful in monitoring algal and Gelbstoff as well as pollutant concentrations.

Primary production in the tropical continental shelf seas bordering northern Australia

NASA Astrophysics Data System (ADS)

Furnas, Miles J.; Carpenter, Edward J.

2016-10-01

Pelagic primary production (14C uptake) was measured 81 times between 1990 and 2013 at sites spanning the broad, shallow Northern Australian Shelf (NAS; 120-145°E) which borders the Australian continent. The mean of all areal production measurements was 1048±109 mg C m-2 d-1 (mean±95% CI). Estimates of areal primary production were correlated with integral upper-euphotic zone chlorophyll stocks (above the 50% and 20% light penetration depths) accessible to ocean color remote sensing and total water column chlorophyll standing crop, but not surface (0-2 m) chlorophyll concentrations. While the NAS is subject to a well characterized monsoonal climate regime (austral summer-NW monsoon -wet: austral winter- SE monsoon -dry), most seasonal differences in means of regional-scale chlorophyll standing crop (11-33 mg Chl m-2 for 12 of 15 season-region combinations) and areal primary production (700-1850 mg C m- day-1 for 12 of 15 season-region combinations) fell within a 3-fold range. Apart from the shallow waters of the Torres Strait and northern Great Barrier Reef, picoplankton (<2 μm size fraction) dominated chlorophyll standing crop and primary production with regional means of picoplankton contributions ranging from 45 to >80%. While the range of our post-1990 areal production estimates overlaps the range of production estimates made in NAS waters during 1960-62, the mean of post-1990 estimates is over 2-fold greater. We regard the difference to be due to improvements in production measurement techniques, particularly regarding the reduction of potential metal toxicity and incubations in more realistic light regimes.

Distribution of inorganic and organic nutrients in the South Pacific Ocean - evidence for long-term accumulation of organic matter in nitrogen-depleted waters

NASA Astrophysics Data System (ADS)

Raimbault, P.; Garcia, N.; Cerutti, F.

2007-08-01

The BIOSOPE cruise of the RV Atalante was devoted to study the biogeochemical properties in the South Pacific between the Marquesas Islands (141° W-8° S) and the Chilean upwelling (73° W-34° S). The 8000 km cruise had the opportunity to encounter different trophic situations, and especially strong oligotrophic conditions in the Central South Pacific Gyre (SPG, between 123° W and 101° W). In this isolated region, nitrate was undetectable between surface and 160-180 m, while regenerated nitrogen (nitrite and ammonium) only revealed some traces (<20 nmoles l-1), even in the subsurface maximum. Integrated nitrate over the photic layer, which reached 165 m, was close to zero. In spite of this severe nitrogen-depletion, phosphate was always present at significant concentrations (≍0.1 μmoles l-1), while silicate maintained at low but classical oceanic levels (≍1 μmoles l-1). In contrast, the Marquesas region (MAR) at west and Chilean upwelling (UPW) at east were characterized by large nutrient contents one hundred to one thousand fold higher than in the SPG. Distribution of surface chlorophyll concentration reflected this gradient of nitrate availability. The lowest value (0.023 nmoles l-1) was measured in the centre of the SPG, where integrated chlorophyll over the photic layer was very weak (≍10 mg m-2), since a great part (up to 50%) of the deep chlorophyll maximum (DCM) was located below the 1% light. But, because of the relative high concentration encountered in the DCM (0.2 μg l-1), chlorophyll a content over the photic layer varied much less (by a factor 2 to 5) than the nitrate content. In contrast to chlorophyll a, integrated content of particulate organic matter (POM) remained more or less constant along the investigated area (500 mmoles m-2, 60 mmoles m-2 and 3.5 mmoles m-2 for particulate organic carbon, particulate organic nitrogen and particulate organic phosphorus, respectively), except in the upwelling where values were two fold higher. Extensive comparison has shown that glass fiber GF/F filters efficiency collected particulate chlorophyll, while a significant fraction of POM (up to 50%) passed trough this filter and was retained by 0.2 μm Teflon membrane. The most striking feature was the large accumulation of dissolved organic matter (DOM) in the SPG relative to surrounding waters, especially dissolved organic carbon (DOC) where concentrations were at levels rarely measured in oceanic waters (>100 μmoles l-1). Due to this large pool of DOM over the whole photic layer of the SPG, integrated values followed an opposite geographical pattern than this of inorganic nutrients with a large accumulation within the centre of the SPG. While suspended particulate matter in the mixed layer had C/N ratio largely conform to Redfield stoichiometry (C/N≍6.6), marked deviations were observed in this excess DOM (C/N≍16 to 23). The existence of C-rich dissolved organic matter is recognized as a feature typical of oligotrophic waters, requiring the over consumption of carbon. Thus, in spite of strong nitrate-depletion leading to low chlorophyll biomass, the closed ecosystem of the SPG can produce a large amount of carbon. The implications of this finding are discussed, the conclusion being that, due to the lack of seasonal vertical mixing and weak lateral advection, the dissolved organic carbon biologically produced can be accumulated and stored in the photic layer for a very long period.

Toxicity of copper on the growth of marine microalgae Pavlova sp. and its chlorophyll-a

NASA Astrophysics Data System (ADS)

Purbonegoro, T.; Suratno; Puspitasari, R.; Husna, N. A.

2018-02-01

Marine microalgae is the primary producer at the base of the marine food chain. Their sensitivity to metal contamination provides important information for predicting the environmental impact of pollution. Toxicity testing using marine microalgae Pavlova sp. was carried out to assess the toxicity of copper on the growth and chlorophyll-a content. Results of this study show that adverse effects were observed by the increase of copper concentration. Cell number began to decrease at the lowest concentration (13 μg/L) and reduced drastically at 98 μg/L. Minimum cell number was observed at the highest concentration (890 μg/L). The inhibition concentration (IC50) value of copper for Pavlova sp. was 51.46 μg/L and at concentrations >29 μgL-1 the chlorophyll-a content decreased dramatically compared to the control. A variation in cell size and morphology was also observed at the higher concentration by the increase in the cell size and loss of setae compared to normal cells.

Influence of frontal zones on the distribution of particulate matter and organic compounds in surface waters of the Atlantic and Southern Oceans

NASA Astrophysics Data System (ADS)

Nemirovskaya, I. A.; Lisitzin, A. P.; Kravchishina, M. D.; Redzhepova, Z. Yu.

2015-10-01

Particulate matter and organic compounds (chlorophyll, lipids, and hydrocarbons) were analyzed in surface waters along the routes of R/Vs Akademik Fedorov (cruise 32) and Akademik Treshnikov (cruise 2) in February-May of 2012 and 2014, respectively, in the course of the 57th and 59th Russian Antarctic expeditions. It was found that the frontal zones exert the primary influence on the concentrations of the mentioned components in the Southern Ocean and in the western part of the Atlantic Ocean. The supply of pollutants into the Eastern Atlantic Ocean on the shelf of the Iberian peninsula results in a pronounced increase in the concentrations of lipids and hydrocarbons causing local anthropogenic pollution zones.

The relationship between sea surface temperature and chlorophyll concentration of phytoplanktons in the Black Sea using remote sensing techniques.

PubMed

Kavak, Mehmet Tahir; Karadogan, Sabri

2012-04-01

Present work investigated the relationship between Chlorophyll (Chl), of phytoplankton biomass, and sea surface temperature (SST) of the Black Sea, using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Advanced Very High Resolution Radiometer (AVHRR) satellite imagery. Satellite derived data could provide information on the amount of sea life present (Brown algae, called kelp, proliferate, supporting new species of sea life, including otters, fish, and various invertebrates) in a given area throughout the world. SST from AVHRR from 1993 to 2008 showed seasonal, annual and interannual variability of temperature, monthly variability Chl from SeaWiFS from 1997 to 2009 has also been investigated. Chl showed two high peaks for the year 1999 and 2008. The correlation between SST and Chl for the same time has been found to be 60%. Correlation was significant at p<0.05. The information could also be useful in connection with studies of global changes in temperature and what effect they could have on the total abundance of marine life.

Regional impacts of ocean color on tropical Pacific variability

NASA Astrophysics Data System (ADS)

Anderson, W.; Gnanadesikan, A.; Wittenberg, A.

2009-08-01

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño) while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

Regional impacts of ocean color on tropical Pacific variability

NASA Astrophysics Data System (ADS)

Anderson, W.; Gnanadesikan, A.; Wittenberg, A.

2009-02-01

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño) while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

Effect of glyphosate acid on biochemical markers of periphyton exposed in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei.

PubMed

Iummato, María Mercedes; Pizarro, Haydée; Cataldo, Daniel; Di Fiori, Eugenia; Dos Santos Afonso, María; Del Carmen Ríos de Molina, María; Juárez, Ángela Beatriz

2017-07-01

Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3, and 6 mg/L in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight, chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels, and superoxide dismutase and catalase activities were determined at days 0, 1, 7, 14, and 26 of the experimental period. Ash-free dry weight was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene to chlorophyll a ratios and enzyme activities, and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in any of these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. Environ Toxicol Chem 2017;36:1775-1784. © 2016 SETAC. © 2017 SETAC.

Quantification of phototrophic biomass on rocks: optimization of chlorophyll-a extraction by response surface methodology.

PubMed

Fernández-Silva, I; Sanmartín, P; Silva, B; Moldes, A; Prieto, B

2011-01-01

Biological colonization of rock surfaces constitutes an important problem for maintenance of buildings and monuments. In this work, we aim to establish an efficient extraction protocol for chlorophyll-a specific for rock materials, as this is one of the most commonly used biomarkers for quantifying phototrophic biomass. For this purpose, rock samples were cut into blocks, and three different mechanical treatments were tested, prior to extraction in dimethyl sulfoxide (DMSO). To evaluate the influence of the experimental factors (1) extractant-to-sample ratio, (2) temperature, and (3) time of incubation, on chlorophyll-a recovery (response variable), incomplete factorial designs of experiments were followed. Temperature of incubation was the most relevant variable for chlorophyll-a extraction. The experimental data obtained were analyzed following a response surface methodology, which allowed the development of empirical models describing the interrelationship between the considered response and experimental variables. The optimal extraction conditions for chlorophyll-a were estimated, and the expected yields were calculated. Based on these results, we propose a method involving application of ultrasound directly to intact sample, followed by incubation in 0.43 ml DMSO/cm(2) sample at 63°C for 40 min. Confirmation experiments were performed at the predicted optimal conditions, allowing chlorophyll-a recovery of 84.4 ± 11.6% (90% was expected), which implies a substantial improvement with respect to the expected recovery using previous methods (68%). This method will enable detection of small amounts of photosynthetic microorganisms and quantification of the extent of biocolonization of stone surfaces.

Assessment of water pollution by airborne measurement of chlorophyll

NASA Technical Reports Server (NTRS)

Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

1972-01-01

Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided.

Biological consequences of a recurrent eddy off Point Conception, California

NASA Technical Reports Server (NTRS)

Haury, Loren R.; Simpson, James J.; Pelaez, Jose; Wisenhahn, David; Koblinsky, Chester J.

1986-01-01

The biological effects on three different time scales (100-day mesoscale, annual, and several-year) of a mesoscale anticyclonic eddy consistently found in shipboard surveys and satellite-sensed data several hundred kilometers southwest of Point Conception, CA, are described. A detailed shipboard study of the eddy in January 1981 found a complex system of fronts in surface chlorophyll at the northern edge of the eddy; microplankton and zooplankton distributions were strongly affected by entrainment processes at the surface and, apparently, at depth. Concurrent satellite coastal zone color scanner ocean color images show agreement with the general surface characteristics of the eddy chlorophyll field but do not reflect features deeper than about 25 m, including the contribution of the deep chlorophyll maximum to the integrated chlorophyll values. Satellite data for the period October 1980 through October 1981 and shipboard data from California Cooperative Oceanic Fisheries Investigations (CalCOFI) for December 1980 to July 1981 show the continued presence of the eddy in the sea surface temperature and color field and in the distributions of surface chlorophyll and zooplankton displacement volume. A review of the CalCOFI survey results from 1949 to the present time demonstrates the recurrent nature of the eddy system on a year-to-year basis. The eddy system appears to have a significant effect on the distribution of both oceanic and nearshore organisms. Offshore transport of coastal species occurs in the form of large entrained plumes or filaments.

A modern robust approach to remotely estimate chlorophyll in coastal and inland zones

NASA Astrophysics Data System (ADS)

Shanmugam, Palanisamy; He, Xianqiang; Singh, Rakesh Kumar; Varunan, Theenathayalan

2018-05-01

The chlorophyll concentration of a water body is an important proxy for representing the phytoplankton biomass. Its estimation from multi or hyper-spectral remote sensing data in natural waters is generally achieved by using (i) the waveband ratioing in two or more bands in the blue-green or (ii) by using a combination of the radiance peak position and magnitude in the red-near-infrared (NIR) spectrum. The blue-green ratio algorithms have been extensively used with satellite ocean color data to investigate chlorophyll distributions in open ocean and clear waters and the application of red-NIR algorithms is often restricted to turbid productive water bodies. These issues present the greatest obstacles to our ability to formulate a modern robust method suitable for quantitative assessments of the chlorophyll concentration in a diverse range of water types. The present study is focused to investigate the normalized water-leaving radiance spectra in the visible and NIR region and propose a robust algorithm (Generalized ABI, GABI algorithm) for chlorophyll concentration retrieval based on Algal Bloom index (ABI) which separates phytoplankton signals from other constituents in the water column. The GABI algorithm is validated using independent in-situ data from various regional to global waters and its performance is further evaluated by comparison with the blue-green waveband ratios and red-NIR algorithms. The results revealed that GABI yields significantly more accurate chlorophyll concentrations (with uncertainties less than 13.5%) and remains more stable in different waters types when compared with the blue-green waveband ratios and red-NIR algorithms. The performance of GABI is further demonstrated using HICO images from nearshore turbid productive waters and MERIS and MODIS-Aqua images from coastal and offshore waters of the Arabian Sea, Bay of Bengal and East China Sea.

Integration of oceanographic data with fin whale calling presence in the Bering Sea

NASA Astrophysics Data System (ADS)

Dasarathy, S.; Berchok, C.; Stabeno, P. J.; Crance, J.

2016-02-01

Through the integration of environmental data with passive acoustic monitoring, it is possible to investigate whether fin whale (Balaenoptera physalus) presence is influenced by environmental factors. Fin whale calling activity and concurrent environmental variables were analyzed from May 2012 to September 2013. These data were collected from passive acoustic and oceanographic moorings located in the Bering Sea. Fin whale calling presence was strongly correlated with three of the eight parameters analyzed: ice concentration, chlorophyll (a proxy for primary production), and temperature. Fin whale calling was negatively correlated with ice concentration; as ice concentration increased, fin whale calling decreased. A strong positive correlation was observed between fin whale calling and chlorophyll. A large spike in chlorophyll concentration in July 2013 preceded fin whale calling at the northern location. Fin whale calling also increased concurrently with a mixing of the water column (evidenced in the temperature data) at a depth of 30 to 50m. Peaks in chlorophyll concentration occurred after the mixing of the water column, and followed an increase in fin whale calling. These data illustrate the relationship between fin whale presence and environmental variables in the Bering Sea. These correlations may be used to predict the impact of climate change on fin whale populations in the rapidly changing environment of the Bering Sea.

Portable chlorophyll meter (PCM-502) values are related to total chlorophyll concentration and photosynthetic capacity in papaya (Carica papaya L.)

USDA-ARS?s Scientific Manuscript database

This study was carried out to verify the practical use of the portable chlorophyll meter-PCM502 (PCM) in two papaya cultivars with contrasting green coloring of the leaf blade (‘Golden’: yellowish-green; ‘Solo’: dark green). The relationship was studied between the photosynthetic process and leaf n...

Estimation of Phytoplankton Accessory Pigments From Hyperspectral Reflectance Spectra: Toward a Global Algorithm

NASA Astrophysics Data System (ADS)

Chase, A. P.; Boss, E.; Cetinić, I.; Slade, W.

2017-12-01

Phytoplankton community composition in the ocean is complex and highly variable over a wide range of space and time scales. Able to cover these scales, remote-sensing reflectance spectra can be measured both by satellite and by in situ radiometers. The spectral shape of reflectance in the open ocean is influenced by the particles in the water, mainly phytoplankton and covarying nonalgal particles. We investigate the utility of in situ hyperspectral remote-sensing reflectance measurements to detect phytoplankton pigments by using an inversion algorithm that defines phytoplankton pigment absorption as a sum of Gaussian functions. The inverted amplitudes of the Gaussian functions representing pigment absorption are compared to coincident High Performance Liquid Chromatography measurements of pigment concentration. We determined strong predictive capability for chlorophylls a, b, c1+c2, and the photoprotective carotenoids. We also tested the estimation of pigment concentrations from reflectance-derived chlorophyll a using global relationships of covariation between chlorophyll a and the accessory pigments. We found similar errors in pigment estimation based on the relationships of covariation versus the inversion algorithm. An investigation of spectral residuals in reflectance data after removal of chlorophyll-based average absorption spectra showed no strong relationship between spectral residuals and pigments. Ultimately, we are able to estimate concentrations of three chlorophylls and the photoprotective carotenoid pigments, noting that further work is necessary to address the challenge of extracting information from hyperspectral reflectance beyond the information that can be determined from chlorophyll a and its covariation with other pigments.

Chlorophyll-a specific volume scattering function of phytoplankton.

PubMed

Tan, Hiroyuki; Oishi, Tomohiko; Tanaka, Akihiko; Doerffer, Roland; Tan, Yasuhiro

2017-06-12

Chlorophyll-a specific light volume scattering functions (VSFs) by cultured phytoplankton in visible spectrum range is presented. Chlorophyll-a specific VSFs were determined based on the linear least squares method using a measured VSFs with different chlorophyll-a concentrations. We found obvious variability of it in terms of spectral and angular shapes of VSF between cultures. It was also presented that chlorophyll-a specific scattering significantly affected on spectral variation of the remote sensing reflectance, depending on spectral shape of b. This result is useful for developing an advance algorithm of ocean color remote sensing and for deep understanding of light in the sea.

Ambiguous dependence of fluorescence intensity of trees on chlorophyll concentration

NASA Astrophysics Data System (ADS)

Zavoruev, Valeriy V.; Zavorueva, Elena N.

2014-11-01

Using fluorimetry Junior PAM (Heinz Walz GmbH, Germany) fluorescence parameters of leaves Prinsepia sinensis, Crataegus chlorocarca M, Acer negúndo, Bétula péndula are studied. It was found that the dependence of maximum fluorescence (Fm) plants on the concentration of chlorophyll depends on the sampling method during of vegetation. The correctness of sampling proves during vegetation is substantiated.

Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral.

PubMed

Caroselli, Erik; Falini, Giuseppe; Goffredo, Stefano; Dubinsky, Zvy; Levy, Oren

2015-01-01

Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography, and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13, 18, and 28°C), and two extreme temperatures expected for 2100 as a consequence of global warming (29 and 32°C). The indicators of photosynthetic performance analyzed (maximum and effective quantum yield) showed that maximum efficiency was reached at 20.0-21.6°C, slightly higher than the annual mean temperature in the field (18°C). Photosynthetic efficiency decreased from 20.0 to 13°C and even more strongly from 21.6 to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18 to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18 to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming.

Concentrations and cycling of DMS, DMSP, and DMSO in coastal and offshore waters of the Subarctic Pacific during summer, 2010-2011

NASA Astrophysics Data System (ADS)

Asher, Elizabeth; Dacey, John W.; Ianson, Debby; Peña, Angelica; Tortell, Philippe D.

2017-04-01

Concentrations of dimethylsulfide (DMS), measured in the Subarctic Pacific during summer 2010 and 2011, ranged from ˜1 to 40 nM, while dissolved dimethylsulfoxide (DMSO) concentrations (range 13-23 nM) exceeded those of dissolved dimethyl sulfoniopropionate (DMSP) (range 1.3-8.8 nM). Particulate DMSP dominated the reduced sulfur pool, reaching maximum concentrations of 100 nM. Coastal and off shore waters exhibited similar overall DMS concentration ranges, but sea-air DMS fluxes were lower in the oceanic waters due to lower wind speeds. Surface DMS concentrations showed statistically significant correlations with various hydrographic variables including the upwelling intensity (r2 = 0.52, p < 0.001) and the Chlorophyll a/mixed layer depth ratio (r2 = 0.52, p < 0.001), but these relationships provided little predictive power at small scales. Stable isotope tracer experiments indicated that the DMSP cleavage pathway always exceeded the DMSO reduction pathway as a DMS source, leading to at least 85% more DMS production in each experiment. Gross DMS production rates were positively correlated with the upwelling intensity, while net rates of DMS production were significantly correlated to surface water DMS concentrations. This latter result suggests that our measurements captured dominant processes driving surface DMS accumulation across a coastal-oceanic gradient.

Evaluating lake phytoplanton response to human disturbance and climate change using satellite imagery

NASA Astrophysics Data System (ADS)

Novitski, Linda Nicole

Accurate and cost-effective assessment of water quality is necessary for proper management and restoration of inland water bodies susceptible to algal bloom conditions. Landsat and MODIS satellite images were used to create chlorophyll and Secchi depth predictive models for algal assessment of Great Lakes and other lakes of the United States. Boosted regression tree (BRT) models using satellite imagery are both easy to use and can have high predictive performance. BRT models inferred chlorophyll and Secchi depth more accurately than linear regression models for all study locations. Inferred chlorophyll of inner Saginaw Bay was subsequently used in ecological models to help understand the ecological drivers of algal blooms in this ecosystem. For small lakes (non-Great Lakes), the best national Landsat model for ln-transformed chlorophyll was the BRT model and had a cross-validation R 2 of 0.44 and a 0.76 ln-transformed mug/L RMSE. The best national Landsat model for Secchi depth was also a BRT model that had an adjusted R 2 of 0.52 and a 0.80 m RMSE. We assessed the applicability of the national chlorophyll model for ecological analysis by comparing the total phosphorus- chlorophyll relationship with chlorophyll determined from sampling or remote sensing, which showed the total phosphorus- chlorophyll relationship had an adjusted R2 = 0.58 and 1.02 ln-transformed microg/L RMSE with sampled chlorophyll versus an adjusted R2 = 0.56 and 1.04 ln-transformed mug/L RMSE with chlorophyll determined by the boosted regression tree remote sensing model. For Great Lakes models, the MODIS BRT model predicted chlorophyll most accurately of the three BRT models and compared well to other models in the literature. BRT models for Landsat ETM+ and TM more accurately predicted chlorophyll than the MSS model and all Landsat models had favorable results when compared to the literature. BRT chlorophyll predictive models are useful in helping to understand historical, long-term chlorophyll trends and to inform us of how climate change may alter ecosystems in the future. In inner Saginaw Bay, annual average and upper quartile Landsat-derived chlorophyll decreased from 7.44 to 6.62 and 8.38 to 7.38 mug/L between 1973-1982, and annual upper quartile of 8-day phosphorus loads increased from 5.29 to 6.79 kg between 1973-2012. Simple linear and multiple regression models and Wilcoxon rank test results for MODIS and Landsat-derived chlorophyll indicate that distance from the Saginaw River mouth influences chlorophyll concentration in Saginaw Bay; Landsat-derived surface water temperature and phosphorus loads to a lesser extent. Mixed-effect models for MODIS and Landsat-derived chlorophyll were related to chlorophyll better than simple linear or multiple regressions, with random effects of pixel and sample date contributing substantially to predictive power (NSE=0.35-70), though phosphorus loads, distance to Saginaw River mouth, and water were significant fixed effects in most models. Water quality changes in Saginaw Bay between 1972-2012 were influenced by phosphorus loading and distance to the Saginaw River's mouth. Landsat and MODIS imagery are complementary platforms because of the long history of Landsat operation and the finer spectral resolution and image frequency of MODIS. Remote sensing water quality assessment tools can be valuable for limnological study, ecological assessment, and water resource management.

Estimating chlorophyll with thermal and broadband multispectral high resolution imagery from an unmanned aerial system using relevance vector machines for precision agriculture

NASA Astrophysics Data System (ADS)

Elarab, Manal; Ticlavilca, Andres M.; Torres-Rua, Alfonso F.; Maslova, Inga; McKee, Mac

2015-12-01

Precision agriculture requires high-resolution information to enable greater precision in the management of inputs to production. Actionable information about crop and field status must be acquired at high spatial resolution and at a temporal frequency appropriate for timely responses. In this study, high spatial resolution imagery was obtained through the use of a small, unmanned aerial system called AggieAirTM. Simultaneously with the AggieAir flights, intensive ground sampling for plant chlorophyll was conducted at precisely determined locations. This study reports the application of a relevance vector machine coupled with cross validation and backward elimination to a dataset composed of reflectance from high-resolution multi-spectral imagery (VIS-NIR), thermal infrared imagery, and vegetative indices, in conjunction with in situ SPAD measurements from which chlorophyll concentrations were derived, to estimate chlorophyll concentration from remotely sensed data at 15-cm resolution. The results indicate that a relevance vector machine with a thin plate spline kernel type and kernel width of 5.4, having LAI, NDVI, thermal and red bands as the selected set of inputs, can be used to spatially estimate chlorophyll concentration with a root-mean-squared-error of 5.31 μg cm-2, efficiency of 0.76, and 9 relevance vectors.

Inherent optical properties and satellite retrieval of chlorophyll concentration in the lagoon and open ocean waters of New Caledonia.

PubMed

Dupouy, Cécile; Neveux, Jacques; Ouillon, Sylvain; Frouin, Robert; Murakami, Hiroshi; Hochard, Sébastien; Dirberg, Guillaume

2010-01-01

The retrieval of chlorophyll-a concentration from remote sensing reflectance (Rrs) data was tested with the NASA OC4v4 algorithm on the inner New Caledonian lagoon (Case 2) and adjacent open ocean (Case 1) waters. The input to OC4v4 was Rrs measured in situ or modeled from water's inherent optical properties (2001-2007). At open ocean stations, backscattering and absorption coefficients were correlated with chlorophyll (R(2)=0.31-0.51, respectively), in agreement with models for Case 1 waters. Taking spectrofluorometric measurement as reference, the OC4v4 model leads to an average underestimation of 33% of the chlorophyll concentration. For the lagoon waters, OC4v4 performed inadequately because the backscattering coefficient, highly correlated with turbidity and suspended matter (R(2)=0.98), was poorly correlated to chlorophyll (R(2)=0.42). The OC4v4 performance was better in deep lagoon waters for stations with a TDT index (Tchla x depth/turbidity) higher than 19 mg m(-2) NTU(-1) (R(2)=0.974, bias=10.2%). Global Imager Rrs provided a good estimate of Tchla (R(2)=0.79, N=28) in the deeper part of the lagoon. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

The Arabian Sea as a high-nutrient, low-chlorophyll region during the late Southwest Monsoon

NASA Astrophysics Data System (ADS)

Naqvi, S. W. A.; Moffett, J. W.; Gauns, M. U.; Narvekar, P. V.; Pratihary, A. K.; Naik, H.; Shenoy, D. M.; Jayakumar, D. A.; Goepfert, T. J.; Patra, P. K.; Al-Azri, A.; Ahmed, S. I.

2010-07-01

Extensive observations were made during the late Southwest Monsoon of 2004 over the Indian and Omani shelves, and along a transect that extended from the southern coast of Oman to the central west coast of India, tracking the southern leg of the US JGOFS expedition (1994-1995) in the west. The data are used, in conjunction with satellite-derived data, to investigate long-term trends in chlorophyll and sea surface temperature, indicators of upwelling intensity, and to understand factors that control primary production (PP) in the Arabian Sea, focussing on the role of iron. Our results do not support an intensification of upwelling in the western Arabian Sea, reported to have been caused by the decline in the winter/spring Eurasian snow cover since 1997. We also noticed, for the first time, an unexpected development of high-nutrient, low-chlorophyll condition off the southern Omani coast. This feature, coupled with other characteristics of the system, such as a narrow shelf and relatively low iron concentrations in surface waters, suggest a close similarity between the Omani upwelling system and the Peruvian and California upwelling systems, where PP is limited by iron. Iron limitation of PP may complicate simple relationship between upwelling and PP assumed by previous workers, and contribute to the anomalous offshore occurrence of the most severe oxygen (O2) depletion in the region. Over the much wider Indian shelf, which experiences large-scale bottom water O2-depletion in summer, adequate iron supply from reducing bottom-waters and sediments seems to support moderately high PP; however, such production is restricted to the thin, oxygenated surface layer, probably because of the unsuitability of the O2-depleted environment for the growth of oxygenic photosynthesizers.

Subsurface chlorophyll maximum layers: enduring enigma or mystery solved?

PubMed

Cullen, John J

2015-01-01

The phenomenon of subsurface chlorophyll maximum layers (SCMLs) is not a unique ecological response to environmental conditions; rather, a broad range of interacting processes can contribute to the formation of persistent layers of elevated chlorophyll a concentration (Chl) that are nearly ubiquitous in stratified surface waters. Mechanisms that contribute to the formation and maintenance of the SCMLs include a local maximum in phytoplankton growth rate near the nutricline, photoacclimation of pigment content that leads to elevated Chl relative to phytoplankton biomass at depth, and a range of physiologically influenced swimming behaviors in motile phytoplankton and buoyancy control in diatoms and cyanobacteria that can lead to aggregations of phytoplankton in layers, subject to grazing and physical control. A postulated typical stable water structure characterizes consistent patterns in vertical profiles of Chl, phytoplankton biomass, nutrients, and light across a trophic gradient structured by the vertical flux of nutrients and characterized by the average daily irradiance at the nutricline. Hypothetical predictions can be tested using a nascent biogeochemical global ocean observing system. Partial results to date are generally consistent with predictions based on current knowledge, which has strong roots in research from the twentieth century.

Coherent stimulated light emission (lasing) in covalently linked chlorophyll dimers

PubMed Central

Hindman, James C.; Kugel, Roger; Wasielewski, Michael R.; Katz, Joseph J.

1978-01-01

The covalently linked chlorophyll a dimer exhibits remarkably different properties in the folded and open configurations. In the folded configuration the absorption maximum is at 695 nm and the fluorescence maximum is at 730 nm. Laser output at 733 and 735 nm is obtained for solutions in wet benzene and 0.1 M ethanol/toluene, respectively. Measurements of fluorescence lineshapes, made with a transverse excited atmospheric (TEA) nitrogen laser for excitation, show the lifetime shortening associated with stimulated emission resulting from appreciable concentrations of molecules in S1 excited states. In contrast, the open dimer has absorption and fluorescence spectra essentially the same as those of chlorophyll a monomer. Unlike either the folded dimer or chlorophyll a monomer, the open dimer shows no laser emission or fluorescene lifetime shortening. It does not appear that the behavior of the open dimer can be explained in terms of excimer or triplet formation or by nonradiative decay processes. It is suggested that absorption of the exciting radiation by S1, leading to the formation of an exciplex or charge transfer state, may be involved. Significantly, no large changes in fluorescence quantum yield or fluorescence lifetime are observed for these dimers as compared to monomer chlorophyll. This suggests that concentration quenching and lifetime shortening in condensed chlorophyll systems involve more than the simple proximity of two chlorophyll molecules. Images PMID:16592524

Assessment of chlorophyll variability along the northwestern coast of Iberian Peninsula

NASA Astrophysics Data System (ADS)

Picado, A.; Alvarez, I.; Vaz, N.; Varela, R.; Gomez-Gesteira, M.; Dias, J. M.

2014-10-01

The northwestern coast of the Iberian Peninsula is characterized by a high primary production mainly supported by coastal upwelling, creating an extraordinary commercial interest for fisheries and aquaculture. Considering chlorophyll-a (Chl-a) as an indicator of primary production, its spatio-temporal variability was researched in this study in the surface water of this upwelling region from 1998 to 2007. Satellite derived Chl-a, Sea Surface Temperature (SST) and Ekman transport data as well as the inflow of the main rivers discharging into the study area were used to investigate the origin of the Chl-a concentration. Empirical Orthogonal Function (EOF) analysis of weekly Chl-a images was performed, as well as correlation analysis between Chl-a concentration, Ekman transport and river discharge. EOF results suggest that the highest Chl-a concentration occurs near the coast up to 60 km offshore. The interannual variability of Chl-a, SST and Ekman transport was also studied considering summer and winter months. Generally, 2005, 2006 and 2007 were the most productive years during the summer months with high Chl-a concentrations along the coast associated to the strong upwelling conditions observed. Otherwise, 1998 seemed to be the most productive year during winter. The absence of upwelling favorable conditions together with localized low SST and considerable discharges, suggests that the high Chl-a concentrations observed during this period are mainly due to the entrance of nutrients through river runoff. However, in winter, high concentrations of colored dissolved organic matter (CDOM), associated with river runoff, are present in the ocean surface, leading to an erroneous strong signal of the satellite. During winter correlations of 0.58 and 0.49 were found between Chl-a concentration and Douro and Minho discharges, respectively, evidencing that high Chl-a concentration was related with river runoff. Otherwise, during summer, Chl-a and Ekman transport exhibited a correlation of - 0.38 indicating that high Chl-a is associated to upwelling events. In summary, it was found that the spatio-temporal variability of Chl-a along the northwestern coast of Iberian Peninsula exhibited the clear influence of upwelling events during summer. Conversely, the variability during winter was mainly due to entrance of nutrients through the rivers discharge which flow into the area.

Vertical nutrient fluxes, turbulence and the distribution of chlorophyll a in the north-eastern North Sea

NASA Astrophysics Data System (ADS)

Bendtsen, Jørgen; Richardson, Katherine

2017-04-01

During summer the northern North Sea is characterized by nutrient rich bottom water masses and nutrient poor surface layers. This explains the distribution of chlorophyll a in the water column where a subsurface maximum, referred to as the deep chlorophyll maximum (DCM), often is present during the growth season. Vertical transport of nutrients between bottom water masses and the well lit surface layer stimulates phytoplankton growth and this generally explains the location of the DCM. However, a more specific understanding of the interplay between vertical transports, nutrient fluxes and phytoplankton abundance is required for identifying the nature of the vertical transport processes, e.g the role of advection versus vertical turbulent diffusion or the role of localized mixing associated with mesoscale eddies. We present results from the VERMIX study in the north-eastern North Sea where nutrients, chlorophyll a and turbulence profiles were measured along five north-south directed transects in July 2016. A high-resolution sampling program, with horizontal distances of 1-10 km between CTD-stations, resolved the horizontal gradients of chlorophyll a across the steep bottom slope from the relatively shallow central North Sea ( 50-80 m) towards the deep Norwegian Trench (>700 m). Low oxygen concentrations in the bottom water masses above the slope indicated enhanced biological production where vertical mixing would stimulate phytoplankton growth around the DCM. Measurements of variable fluorescence (Fv/Fm) showed elevated values in the DCM which demonstrates a higher potential for electron transport in the Photosystem II in the phytoplankton cells, i.e. an indication of nutrient-rich conditions favorable for phytoplankton production. Profiles of the vertical shear and microstructure of temperature and salinity were measured by a VMP-250 turbulence profiler and the vertical diffusion of nutrients was calculated from the estimated vertical turbulent diffusivity and the distributions of nutrients. Results from the five transects and two time-series stations, where vertical profiles were made at hourly intervals, showed that vertical mixing processes above the slope increased the vertical transport of nutrients significantly and mixing above the slope can explain the hydrographic features and the distribution of the DCM in the area.

An extended PROSPECT: Advance in the leaf optical properties model separating total chlorophylls into chlorophyll a and b.

PubMed

Zhang, Yao; Huang, Jingfeng; Wang, Fumin; Blackburn, George Alan; Zhang, Hankui K; Wang, Xiuzhen; Wei, Chuanwen; Zhang, Kangyu; Wei, Chen

2017-07-25

The PROSPECT leaf optical model has, to date, well-separated the effects of total chlorophyll and carotenoids on leaf reflectance and transmittance in the 400-800 nm. Considering variations in chlorophyll a:b ratio with leaf age and physiological stress, a further separation of total plant-based chlorophylls into chlorophyll a and chlorophyll b is necessary for advanced monitoring of plant growth. In this study, we present an extended version of PROSPECT model (hereafter referred to as PROSPECT-MP) that can combine the effects of chlorophyll a, chlorophyll b and carotenoids on leaf directional hemispherical reflectance and transmittance (DHR and DHT) in the 400-800 nm. The LOPEX93 dataset was used to evaluate the capabilities of PROSPECT-MP for spectra modelling and pigment retrieval. The results show that PROSPECT-MP can both simultaneously retrieve leaf chlorophyll a and b, and also performs better than PROSPECT-5 in retrieving carotenoids concentrations. As for the simulation of DHR and DHT, the performances of PROSPECT-MP are similar to that of PROSPECT-5. This study demonstrates the potential of PROSPECT-MP for improving capabilities of remote sensing of leaf photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) and for providing a framework for future refinements in the modelling of leaf optical properties.

Spatial and Diel Variability in Photosynthetic and Photoprotective Pigments in Shallow Benthic Communities

DTIC Science & Technology

2002-09-30

phycocyanin analyses, the sediments were extracted repeatedly with a phosphate buffer. An ultrasonicator was used to extract pigments. Concentrations...species composition. While phycoerythrin concentrations varied around 20-fold, phycocyanin varied approximately 70-fold. The highest levels of...chlorophylls a and c, and phycocyanin were found in grapestone sediments and the lowest levels of chlorophylls a and c were found in ooid sands

Chlorophyll Degradation: The Tocopherol Biosynthesis-Related Phytol Hydrolase in Arabidopsis Seeds Is Still Missing1[C][W][OPEN

PubMed Central

Zhang, Wei; Liu, Tianqi; Ren, Guodong; Hörtensteiner, Stefan; Zhou, Yongming; Cahoon, Edgar B.; Zhang, Chunyu

2014-01-01

Phytyl diphosphate (PDP) is the prenyl precursor for tocopherol biosynthesis. Based on recent genetic evidence, PDP is supplied to the tocopherol biosynthetic pathway primarily by chlorophyll degradation and sequential phytol phosphorylation. Three enzymes of Arabidopsis (Arabidopsis thaliana) are known to be capable of removing the phytol chain from chlorophyll in vitro: chlorophyllase1 (CLH1), CLH2, and pheophytin pheophorbide hydrolase (PPH), which specifically hydrolyzes pheophytin. While PPH, but not chlorophyllases, is required for in vivo chlorophyll breakdown during Arabidopsis leaf senescence, little is known about the involvement of these phytol-releasing enzymes in tocopherol biosynthesis. To explore the origin of PDP for tocopherol synthesis, seed tocopherol concentrations were determined in Arabidopsis lines engineered for seed-specific overexpression of PPH and in single and multiple mutants in the three genes encoding known dephytylating enzymes. Except for modestly increasing tocopherol content observed in the PPH overexpressor, none of the remaining lines exhibited significantly reduced tocopherol concentrations, suggesting that the known chlorophyll-derived phytol-releasing enzymes do not play major roles in tocopherol biosynthesis. Tocopherol content of seeds from double mutants in NONYELLOWING1 (NYE1) and NYE2, regulators of chlorophyll degradation, had modest reduction compared with wild-type seeds, although mature seeds of the double mutant retained significantly higher chlorophyll levels. These findings suggest that NYEs may play limited roles in regulating an unknown tocopherol biosynthesis-related phytol hydrolase. Meanwhile, seeds of wild-type over-expressing NYE1 had lower tocopherol levels, suggesting that phytol derived from NYE1-dependent chlorophyll degradation probably doesn’t enter tocopherol biosynthesis. Potential routes of chlorophyll degradation are discussed in relation to tocopherol biosynthesis. PMID:25059706

AVIRIS spectra correlated with the chlorophyll concentration of a forest canopy

NASA Technical Reports Server (NTRS)

Kupiec, John; Smith, Geoffrey M.; Curran, Paul J.

1993-01-01

Imaging spectrometers have many potential applications in the environmental sciences. One of the more promising applications is that of estimating the biochemical concentrations of key foliar biochemicals in forest canopies. These estimates are based on spectroscopic theory developed in agriculture and could be used to provide the spatial inputs necessary for the modeling of forest ecosystem dynamics and productivity. Several foliar biochemicals are currently under investigation ranging from those with primary absorption features in visible to middle infrared wavelengths (e.g., water, chlorophyll) to those with secondary to tertiary absorption features in this part of the spectrum (e.g., nitrogen, lignin). The foliar chemical of interest in this paper is chlorophyll; this is a photoreceptor and catalyst for the conversion of sunlight into chemical energy and as such plays a vital role in the photochemical synthesis of carbohydrates in plants. The aim of the research reported here was to determine if the chlorophyll concentration of a forest canopy could be correlated with the reflectance spectra recorded by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS).

Identification and determination of flavonoids, carotenoids and chlorophyll concentration in Cynodon dactylon (L.) by HPLC analysis.

PubMed

Muthukrishnan, Saradha Devi; Kaliyaperumal, Ashokkumar; Subramaniyan, Annapoorani

2015-01-01

Cynodon dactylon (L.) is a potent medicinal plant in the traditional and current Indian medicinal systems. The objective of this research was to find out the levels of flavonoids, carotenoids and chlorophyll b in C. dactylon leaves by high-performance liquid chromatography (HPLC) equipped with a diode array detector. HPLC analysis revealed that total carotenoid and total flavonoid concentration were 62 mg/100 g and 249.1 μg/g, respectively. The mean chlorophyll b was 85.1 mg/100 g in C. dactylon. Among the flavonoids, quercetin (164.7 μg/g) was the major flavonoid followed by kaempferol (48.2 μg/g), rutin (18.4 μg/g), catechin (12.1 μg/g) and myricetin (5.7 μg/g). Of the carotenoids, β-carotene (35.2 mg/100 g) was predominant followed by lutein (17.0 mg/100 g), violaxanthin (5.8 mg/100 g) and zeaxanthin (4.2 mg/100 g). Chlorophyll b concentration was 85.1 mg/100 g in C. dactylon. The results of this investigation should be useful information for further pharmacological studies.

Biodiversity, bioaccumulation and physiological changes in lichens growing in the vicinity of coal-based thermal power plant of Raebareli district, north India.

PubMed

Bajpai, Rajesh; Upreti, Dalip K; Nayaka, S; Kumari, B

2010-02-15

The lichen diversity assessment carried out around a coal-based thermal power plant indicated the increase in lichen abundance with the increase in distance from power plant in general. The photosynthetic pigments, protein and heavy metals were estimated in Pyxine cocoes (Sw.) Nyl., a common lichen growing around thermal power plant for further inference. Distributions of heavy metals from power plant showed positive correlation with distance for all directions, however western direction has received better dispersion as indicated by the concentration coefficient-R(2). Least significant difference analysis showed that speed of wind and its direction plays a major role in dispersion of heavy metals. Accumulation of Al, Cr, Fe, Pb and Zn in the thallus suppressed the concentrations of pigments like chlorophyll a, chlorophyll b and total chlorophyll, however, enhanced the level of protein. Further, the concentrations of chlorophyll contents in P. cocoes increased with the decreasing the distance from the power plant, while protein, carotenoid and phaeophytisation exhibited significant decrease.

Habitat of calling blue and fin whales in the Southern California Bight

NASA Astrophysics Data System (ADS)

Sirovic, A.; Chou, E.; Roch, M. A.

2016-02-01

Northeast Pacific blue whale B calls and fin whale 20 Hz calls were detected from passive acoustic data collected over seven years at 16 sites in the Southern California Bight (SCB). Calling blue whales were most common in the coastal areas, during the summer and fall months. Fin whales began calling in fall and continued through winter, in the southcentral SCB. These data were used to develop habitat models of calling blue and fin whales in areas of high and low abundance in the SCB, using remotely sensed variables such as sea surface temperature, sea surface height, chlorophyll a, and primary productivity as model covariates. A random forest framework was used for variable selection and generalized additive models were developed to explain functional relationships, evaluate relative contribution of each significant variable, and investigate predictive abilities of models of calling whales. Seasonal component was an important feature of all models. Additionally, areas of high calling blue and fin whale abundance both had a positive relationship with the sea surface temperature. In areas of lower abundance, chlorophyll a concentration and primary productivity were important variables for blue whale models and sea surface height and primary productivity were significant covariates in fin whale models. Predictive models were generally better for predicting general trends than absolute values, but there was a large degree of variation in year-to-year predictability across different sites.

Phytoplankton characteristics and hydrological conditions in the western part of the Sea of Okhotsk in the spring of 1999 and 2000 based on expeditionary and satellite data

NASA Astrophysics Data System (ADS)

Zakharkov, S. P.; Selina, M. S.; Vanin, N. S.; Shtraikhert, E. A.; Biebov, N.

2007-08-01

Using the data obtained in 1999 2000 during the spring bloom of phytoplankton (late May early June), the variability of the pigment concentrations, the phytoplankton biomass and species compositions, and the hydrological conditions on the eastern shelf of Sakhalin Island was studied. The study resulted in revealing 135 microalgae species belonging to eight divisions. The most diversely presented were the Dinophyta dinoflagellates and Bacillariophyta diatoms (70 and 53 species, respectively). The concentration of chlorophyll a in the euphotic zone amounted, on average, to 3.8 mg/m3 in 1999 and 2.4 mg/m3 in 2000. It was shown that, in the northern and southern parts of the coastal zone, the concentration of chlorophyll a and the phytoplankton density in the spring were considerably different and depended on the hydrological conditions. In the north, their maximum values were found in the area of the depth break and were determined by the tidal mixing. The increased algae concentrations and temperature inversions at depths of 400 600 m confirm the downslope sliding of the near-bottom shelf waters. In the southern part, the high phytoplankton concentrations in the surface layer in 1999 confirmed by the monthly averaged estimates from the SeaWiFS satellite color scanner were caused by the abnormal northward propagation of the Soya Current waters and by intense tidal mixing.

Novel decomposition products of chlorophyll- a in continental shelf (Louisiana shelf) sediments: formation and transformation of carotenol chlorin esters

NASA Astrophysics Data System (ADS)

Chen, Nianhong; Bianchi, Thomas S.; Bland, John M.

2003-06-01

In April 2000, we collected box cores from five stations along a cross-shelf transect on the Louisiana (LA) continental shelf. Novel esters of carotenols and chlorins (carotenoid chlorin esters, CCEs), which are highly specific grazing markers, were identified in surface and deep sediments (>10 cm) from the LA shelf. Chlorophyll- a inventory indicated that CCEs are one of the major decay products of chlorophyll- a in shelf sediments. Abundances of total CCEs (9-18%) in surface sediments along the cross-shelf transect were comparable to the abundance of pheophytin- a, pyropheophytin- a, and total steryl chlorin esters (SCEs). Prior work has identified four CCEs which have dehydrated fucoxanthin/fucoxanthinol as a substitute alcohol of phytol. We report on four newly identified CCEs associated with nondehydrated fuxocanthin/fucoxanthinol esterified to (pyro)pheophorbide- a. These nondehydrated CCEs were generally present in lower concentrations than their dehydrated counterparts, but were detectable by atmospheric pressure chemical ionization (APCI) mass spectrometry coupled with high-performance liquid chromatography (HPLC). We attributed differences between this study and previous work to the time allowed for predepositional decay and grazing processes to occur. The rapid sedimentation of CCEs in the shallow water column (ca. 10 m) on the LA shelf allowed for effective burial of all CCEs compared to the deeper water column regions sampled by previous work. This speculation is supported by the fact that the concentrations of CCEs with nondehydrated fucoxanthin/fucoxanthinol were extremely low in sediments from the site on the outer LA shelf with a deeper (253 m) water column. We also tentatively identified an additional CCE and its isomer as fucoxanthinol didehydrate pyropheophorbide- a ester. We suggest that the formation and transformation of CCEs are primarily controlled by the following three biologically mediated reactions: demethoxycarbonylation, dehydration, and deacetylation. Our laboratory copepod grazing experiment also confirmed that CCEs can be excellent class-specific biomarkers of zooplankton grazing on phytoplankton.

Analysis of the Light-harvesting Pigment-Protein Complex of Wild Type and a Chlorophyll-b-less Mutant of Barley 1

PubMed Central

Burke, John J.; Steinback, Katherine E.; Arntzen, Charles J.

1979-01-01

we have compared chloroplast lamellae isolated from a chlorophyll-b-less mutant and wild type barley (Hordeum vulgare). The results demonstrate that: (a) one of the two major polypeptides comprising the lightharvesting complex (LHC) is present in the chlorophyll-b-less mutant; (b) higher cation concentrations are required to maintain grana stacks in the mutant; and (c) cation effects on excitation energy distribution are present in the chlorophyll-b-less mutant but are reduced in amount and are dependent on higher concentrations of cations. We interpret these data to support the concept that the LHC mediates cation-induced grana stacking and cation regulation of excitation energy distribution between photosystems I and Ii in chloroplast lamellae. A partial LHC complement in the mutant alters the quantitative cation requirement for both phenomena, but not the over-all qualitative response. Images PMID:16660704

Airborne discrimination between ice and water - Application to the laser measurement of chlorophyll-in-water in a marginal ice zone

NASA Technical Reports Server (NTRS)

Hoge, Frank E.; Wright, C. Wayne; Swift, Robert N.; Yungel, James K.

1989-01-01

The concurrent active-passive measurement capabilities of the NASA Airborne Oceanographic Lidar have been used to (1) discriminate between ice and water in a large ice field within the Greenland Sea and (2) achieve the detection and measurement of chlorophyll-in-water by laser-induced and water-Raman-normalized pigment fluorescence. Passive upwelled radiances from sea ice are significantly stronger than those from the neighboring water, even when the optical receiver field-of-view is only partially filled with ice. Thus, weaker passive upwelled radiances, together with concurrently acquired laser-induced spectra, can rather confidently be assigned to the intervening water column. The laser-induced spectrum can then be processed using previously established methods to measure the chlorophyll-in-water concentration. Significant phytoplankton patchiness and elevated chlorophyll concentrations were found within the waters of the melting ice compared to ice-free regions just outside the ice field.

Combined Effect of Reduced Band Number and Increased Bandwidth on Shallow Water Remote Sensing: The Case of WorldView 2

DTIC Science & Technology

2013-05-01

shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...functions ( BRDF ) were compared with measurements made just beneath the water’s surface. In Case I water, the set of simulations that varied the particle...scattering phase function depending on chlorophyll concentration agreed more closely with the data than other models . In Case II water, however, the

Temporal and Spatial Variability of Black Sea Hydrodynamics and Chlorophyll: A Concentration with Connection to Wind Forcing

DTIC Science & Technology

2013-03-01

radar sensors that are designed to transmit a pulse of a microwave signal to the surface of the earth in order to measure the echoed microwave energy...Jer Huang for his support and sharing his expertise unconditionally. I would like to acknowledge Mr. Chenwu Fan and Mr. Michael Cook . Your...http://www.aviso.oceanobs.com/en/altimetry/history.html) 33 b. Principle High-frequency signals (at least 1700 pulses Hz) are emitted to Earth by

Dynamics of plankton populations in upwelling areas

NASA Technical Reports Server (NTRS)

Szekielda, K. H. (Principal Investigator)

1975-01-01

The author has identified the following significant results. Spectral properties of the upwelled waters off the NW coast of Africa were studied with observations derived from aircraft and Skylab. Results indicate that the two-channel, ratio approach is ineffective in determining surface chlorophyll concentrations. Ocean color boundaries and temperature gradients were found to be directly correlated with each other and also with fishing effort in the upwelling region. Photographic and scanner data derived from Skylab were effective in locating ocean boundaries and mapping temperature distributions.

Characteristic sediment and water column chlorophyll-a in the sea cucumber’s Paracaudina sp. habitat on the Kenjeran Water, Surabaya

NASA Astrophysics Data System (ADS)

Widianingsih, W.; Zaenuri, M.; Anggoro, S.; Kusumaningrum, H. P.; Hartati, R.

2018-03-01

The study of characteristic sediment and water column chlorophyll-a has an important role in the sea cucumber habitat. Sediment chlorophyll-a represents a productivity primer for the benthic community. This research has a purpose to investigate characteristic sediment and water column chlorophyll-a on the Kenjeran water, Surabaya. Sediment samples were collected by the ekman grab for analysis, grain size and nutrient. The sample for sediment chlorophyll-a was taken by core sampler. The water samples were taken with Nansen Bottles. According to the research result, the values of sediment chlorophyll-a at station 10, 11 and 12 were higher than the other stations. In contrast, the value of chlorophyll-a in the column water had almost the same value for each station. The sediment chlorophyll-a value on clay and silt sediment type was higher than the fine sand and coarse sediment type. The suitable habitat characteristic for Paracaudina sp. was clay and silt sediment with sediment chlorophyll concentration ranging from 347.82 mg·m-2 to 1135.52 mg·m-2.

Summer diatom blooms in the North Pacific subtropical gyre: 2008-2009.

PubMed

Villareal, Tracy A; Brown, Colbi G; Brzezinski, Mark A; Krause, Jeffrey W; Wilson, Cara

2012-01-01

The summertime North Pacific subtropical gyre has widespread phytoplankton blooms between Hawaii and the subtropical front (∼30°N) that appear as chlorophyll (chl) increases in satellite ocean color data. Nitrogen-fixing diatom symbioses (diatom-diazotroph associations: DDAs) often increase 10(2)-10(3) fold in these blooms and contribute to elevated export flux. In 2008 and 2009, two cruises targeted satellite chlorophyll blooms to examine DDA species abundance, chlorophyll concentration, biogenic silica concentration, and hydrography. Generalized observations that DDA blooms occur when the mixed layer depth is < 70 m are supported, but there is no consistent relationship between mixed layer depth, bloom intensity, or composition; regional blooms between 22-34°N occur within a broader temperature range (21-26°C) than previously reported. In both years, the Hemiaulus-Richelia and Rhizosolenia-Richelia DDAs increased 10(2)-10(3) over background concentrations within satellite-defined bloom features. The two years share a common trend of Hemiaulus dominance of the DDAs and substantial increases in the >10 µm chl a fraction (∼40-90+% of total chl a). Integrated diatom abundance varied 10-fold over <10 km. Biogenic silica concentration tracked diatom abundance, was dominated by the >10 µm size fraction, and increased up to 5-fold in the blooms. The two years differed in the magnitude of the surface chl a increase (2009>2008), the abundance of pennate diatoms within the bloom (2009>2008), and the substantially greater mixed layer depth in 2009. Only the 2009 bloom had sufficient chl a in the >10 µm fraction to produce the observed ocean color chl increase. Blooms had high spatial variability; ocean color images likely average over numerous small events over time and space scales that exceed the individual event scale. Summertime DDA export flux noted at the Hawaii time-series Sta. ALOHA is probably a generalized feature of the eastern N. Pacific north to the subtropical front.

Feeding enhances photosynthetic efficiency in the carnivorous pitcher plant Nepenthes talangensis

PubMed Central

Pavlovič, Andrej; Singerová, Lucia; Demko, Viktor; Hudák, Ján

2009-01-01

Background and Aims Cost–benefit models predict that carnivory can increase the rate of photosynthesis (AN) by leaves of carnivorous plants as a result of increased nitrogen absorption from prey. However, the cost of carnivory includes decreased AN and increased respiration rates (RD) of trapping organs. The principal aim of the present study was to assess the costs and benefits of carnivory in the pitcher plant Nepenthes talangensis, leaves of which are composed of a lamina and a pitcher trap, in response to feeding with beetle larvae. Methods Pitchers of Nepenthes grown at 200 µmol m−2 s−1 photosynthetically active radiation (PAR) were fed with insect larvae for 2 months, and the effects on the photosynthetic processes were then assessed by simultaneous measurements of gas exchange and chlorophyll fluorescence of laminae and pitchers, which were correlated with nitrogen, carbon and total chlorophyll concentrations. Key Results AN and maximum (Fv/Fm) and effective quantum yield of photosystem II (ΦPSII) were greater in the fed than unfed laminae but not in the fed compared with unfed pitchers. Respiration rate was not significantly affected in fed compared with unfed plants. The unfed plants had greater non-photochemical quenching (NPQ) of chlorophyll fluorescence. Higher NPQ in unfed lamina did not compensate for their lower ΦPSII, resulting in lower photochemical quenching (QP) and thus higher excitation pressure on PSII. Biomass and nitrogen and chlorophyll concentration also increased as a result of feeding. The cost of carnivory was shown by lower AN and ΦPSII in pitchers than in laminae, but RD depended on whether it was expressed on a dry weight or a surface area basis. Correlation between nitrogen and AN in the pitchers was not found. Cost–benefit analysis showed a large beneficial effect on photosynthesis from feeding as light intensity increased from 200 to 1000 µmol m−2 s−1 PAR after which it did not increase further. All fed plants began to flower. Conclusion Feeding pitchers with insect larvae increases AN of leaf laminae, due to higher nutrient acquisition, with strong correlation with nitrogen concentration, but AN of pitchers does not increase, despite increased nitrogen concentration in their tissue. Increased AN improves growth and reproduction and is likely to increase the competitive advantage of carnivorous over non-carnivorous plants in nutrient-poor habitats. PMID:19454591

Feeding enhances photosynthetic efficiency in the carnivorous pitcher plant Nepenthes talangensis.

PubMed

Pavlovic, Andrej; Singerová, Lucia; Demko, Viktor; Hudák, Ján

2009-08-01

Cost-benefit models predict that carnivory can increase the rate of photosynthesis (A(N)) by leaves of carnivorous plants as a result of increased nitrogen absorption from prey. However, the cost of carnivory includes decreased A(N) and increased respiration rates (R(D)) of trapping organs. The principal aim of the present study was to assess the costs and benefits of carnivory in the pitcher plant Nepenthes talangensis, leaves of which are composed of a lamina and a pitcher trap, in response to feeding with beetle larvae. Pitchers of Nepenthes grown at 200 micromol m(-2) s(-1) photosynthetically active radiation (PAR) were fed with insect larvae for 2 months, and the effects on the photosynthetic processes were then assessed by simultaneous measurements of gas exchange and chlorophyll fluorescence of laminae and pitchers, which were correlated with nitrogen, carbon and total chlorophyll concentrations. A(N) and maximum (F(v)/F(m)) and effective quantum yield of photosystem II (Phi(PSII)) were greater in the fed than unfed laminae but not in the fed compared with unfed pitchers. Respiration rate was not significantly affected in fed compared with unfed plants. The unfed plants had greater non-photochemical quenching (NPQ) of chlorophyll fluorescence. Higher NPQ in unfed lamina did not compensate for their lower Phi(PSII), resulting in lower photochemical quenching (QP) and thus higher excitation pressure on PSII. Biomass and nitrogen and chlorophyll concentration also increased as a result of feeding. The cost of carnivory was shown by lower A(N) and Phi(PSII) in pitchers than in laminae, but R(D) depended on whether it was expressed on a dry weight or a surface area basis. Correlation between nitrogen and A(N) in the pitchers was not found. Cost-benefit analysis showed a large beneficial effect on photosynthesis from feeding as light intensity increased from 200 to 1000 micromol m(-2) s(-1) PAR after which it did not increase further. All fed plants began to flower. Feeding pitchers with insect larvae increases A(N) of leaf laminae, due to higher nutrient acquisition, with strong correlation with nitrogen concentration, but A(N) of pitchers does not increase, despite increased nitrogen concentration in their tissue. Increased A(N) improves growth and reproduction and is likely to increase the competitive advantage of carnivorous over non-carnivorous plants in nutrient-poor habitats.

Response of maize (Zea mays L. saccharata Sturt) to different concentration treatments of deltamethrin.

PubMed

Duran, Ragbet Ezgi; Kilic, Semra; Coskun, Yasemin

2015-10-01

The aim of this study was to investigate the effect of the deltamethrin pesticide on the biological properties of maize (Zea mays L. saccharata Sturt). Maize seeds were exposed to environmentally relevant dosages (0.01, 0.05, 0.1 and 0.5 ppm) of deltamethrin. On the 7th day of germination, morphological, anatomical and physiological responses were determined. All seedling growth characters were decreased with increasing deltamethrin levels. The most negative effect on the radicle length of maize was observed by the highest deltamethrin concentration with a 61% decrease (P <0.05). Both stomatal density and stomatal dimension reduction were caused by increasing concentrations of deltamethrin. Moreover, the pigments like chlorophyll a, chlorophyll b, total chlorophyll and caretonoids decreased with the increase in deltamethrin concentration. Conversely, anthocyanin and proline content increased in parallel with deltamethrin concentration. As a result, all morphological traits and pigments except for proline and anthocyanin were significantly reduced with an increase in pesticide concentration, compared to control (P <0.05). Copyright © 2015 Elsevier Inc. All rights reserved.

Variations of physicochemical properties in Kalpakkam coastal waters, east coast of India, during southwest to northeast monsoon transition period.

PubMed

Satpathy, Kamala Kanta; Mohanty, Ajit K; Sahu, Gouri; Sarkar, Santosh K; Natesan, Usha; Venkatesan, R; Prasad, M V R

2010-12-01

A significant variation in physicochemical properties of the Kalpakkam coastal waters, eastern part of India, was observed during the event of southwest to northeast monsoon transition. Increase in nitrate, total nitrogen, and silicate concentrations were noticed during post-transition period. Ammonia concentration was at peak during transition period as compared to pre- and post-transition periods. Hypo-saline condition (~23 psu) was observed during post-transition as the surface water salinity decreased by ~10 psu from the pre-transitional values. Turbidity, suspended particulate matter, phosphate and total phosphorous values decreased marginally, coinciding with northward to southward current reversal. A drastic decrease (eightfold) in chlorophyll-a concentration was observed in the coastal water during post-transition period.

Carnivorous syndrome in Asian pitcher plants of the genus Nepenthes.

PubMed

Pavlovic, Andrej; Masarovicová, Elena; Hudák, Ján

2007-09-01

Pitcher plants Nepenthes alata and N. mirabilis are carnivorous species with leaves composed of a photosynthetic part (lamina) and a pitcher trap. This characteristic permitted direct physiological and anatomical comparison between these two distinct parts of the leaves to determine those features involved in the 'carnivorous syndrome', which include low net photosynthetic assimilation rate (A(N)) and low photosynthetic nitrogen use efficiency (PNUE). Photosynthetic rate (A(N)) and respiration rate (R(d)) were measured gasometrically, chlorophyll concentration was determined spectrophotometrically and nitrogen concentration was determined using a CHN elemental analyser in lamina and trap separately. Anatomy of N. alata was observed using light, fluorescence and transmission electron microscopy. A(N), foliar nitrogen and chlorophyll concentration were also compared with values for other carnivorous plant species (genera Sarracenia, Drosera) that combine both autotrophic and carnivorous functions into the same physical organ. It was found that the A(N) in Nepenthes lamina was low and PNUE was only slightly higher or similar in comparison with other carnivorous plants. It was not observed that the pitcher had a higher R(d) than the lamina, but A(N) in the pitcher was significantly lower than in the lamina. Nepenthes possesses a cluster of characters that could result in reduced photosynthesis in the pitcher and be responsible for carnivorous function of the leaf: replacement of chlorophyll-containing cells with digestive glands, low chlorophyll and nitrogen concentration, compact mesophyll with a small portion of intercellular spaces, absence of palisade parenchyma and low stomatal density. Low photosynthetic capacity, nitrogen efficiency, chlorophyll and nitrogen concentration of Nepenthes pitchers was found, together with a set of features that characterized the carnivorous syndrome. Dual use of leaves for photosynthesis and nutrient gain can decrease photosynthetic efficiency in carnivorous plants in general.

Carnivorous Syndrome in Asian Pitcher Plants of the Genus Nepenthes

PubMed Central

Pavlovič, Andrej; Masarovičová, Elena; Hudák, Ján

2007-01-01

Background and Aims Pitcher plants Nepenthes alata and N. mirabilis are carnivorous species with leaves composed of a photosynthetic part (lamina) and a pitcher trap. This characteristic permitted direct physiological and anatomical comparison between these two distinct parts of the leaves to determine those features involved in the ‘carnivorous syndrome’, which include low net photosynthetic assimilation rate (AN) and low photosynthetic nitrogen use efficiency (PNUE). Methods Photosynthetic rate (AN) and respiration rate (Rd) were measured gasometrically, chlorophyll concentration was determined spectrophotometrically and nitrogen concentration was determined using a CHN elemental analyser in lamina and trap separately. Anatomy of N. alata was observed using light, fluorescence and transmission electron microscopy. AN, foliar nitrogen and chlorophyll concentration were also compared with values for other carnivorous plant species (genera Sarracenia, Drosera) that combine both autotrophic and carnivorous functions into the same physical organ. Key Results It was found that the AN in Nepenthes lamina was low and PNUE was only slightly higher or similar in comparison with other carnivorous plants. It was not observed that the pitcher had a higher Rd than the lamina, but AN in the pitcher was significantly lower than in the lamina. Nepenthes possesses a cluster of characters that could result in reduced photosynthesis in the pitcher and be responsible for carnivorous function of the leaf: replacement of chlorophyll-containing cells with digestive glands, low chlorophyll and nitrogen concentration, compact mesophyll with a small portion of intercellular spaces, absence of palisade parenchyma and low stomatal density. Conclusion Low photosynthetic capacity, nitrogen efficiency, chlorophyll and nitrogen concentration of Nepenthes pitchers was found, together with a set of features that characterized the carnivorous syndrome. Dual use of leaves for photosynthesis and nutrient gain can decrease photosynthetic efficiency in carnivorous plants in general. PMID:17664255

Effects of air pollution on cell membrane integrity, spectral reflectance and metal and sulfur concentrations in lichens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garty, J.; Cohen, Y.; Kloog, N.

1997-07-01

The fruticose lichen Ramalina duriaei is generally considered to be sensitive to air pollution. In the present study the authors sought to determine whether thalli of this lichen collected in a remote unpolluted site (the HaZorea Forest, northeast Israel) and transplanted to the Ashdod region (southwest Israel) could provide information on the quality of the air in this area. For this purpose, the concentrations of Pb, Cu, Cd, Ni, Mn, Fe, S, Ca, Mg, Na, and K were determined in in situ thalli collected in the HaZorea Forest in March 1993 and in in situ and transplanted thalli retrieved inmore » June 1993. The concentration of these elements in R. duriaei thalli was analyzed in comparison with physiological parameters such as the integrity of cell membranes, chlorophyll content, and alterations in reflectance responses from lichen thalli. Thalli transplanted to several industrial sites in the town of Ashdod for a period of 100 d accumulated high concentrations of Pb, Cd, Ni, Fe, S, Mg, Na, Ca, and K. The concentration of S in thalli transplanted to the Ashdod region was found to correlate with damage caused to cell membranes and showed and inverse correlation with the chlorophyll content and with the reflectance response of the lichen. The electrical conductivity values corresponding to membrane integrity in the lichen thallus showed an inverse correlation with the ratio of chlorophyll a to pheophytin a, indicating the integrity of the photobiontic chlorophyll and with normalized-difference vegetation index values corresponding to the reflectance response of the thallus. The chlorophyll integrity correlated with the reflectance response. Magnesium accumulated in the lichen thalli in dusty sites and was found to correlate with damage caused to membranes.« less

Chlorophyll a reconstruction from in situ measurements: 1. Method description

NASA Astrophysics Data System (ADS)

Fründt, B.; Dippner, J. W.; Waniek, J. J.

2015-02-01

Understanding the development of primary production is essential for projections of the global carbon cycle in the context of climate change. A chlorophyll a hindcast that serves as a primary production indicator was obtained by fitting in situ measurements of nitrate, chlorophyll a, and temperature. The resulting fitting functions were adapted to a modeled temperature field. The method was applied to observations from the Madeira Basin, in the northeastern part of the oligotrophic North Atlantic Subtropical Gyre and yielded a chlorophyll a field from 1989 to 2008 with a monthly resolution validated with remotely measured surface chlorophyll a data by SeaWiFS. The chlorophyll a hindcast determined with our method resolved the seasonal and interannual variability in the phytoplankton biomass of the euphotic zone as well as the deep chlorophyll maximum. Moreover, it will allow estimation of carbon uptake over long time scales.

Influence of the tidal front on the three-dimensional distribution of spring phytoplankton community in the eastern Yellow Sea.

PubMed

Choi, Byoung-Ju; Lee, Jung A; Choi, Jae-Sung; Park, Jong-Gyu; Lee, Sang-Ho; Yih, Wonho

2017-04-01

Hydrographic observation and biological samplings were conducted to assess the distribution of phytoplankton community over the sloping shelf of the eastern Yellow Sea in May 2012. The concentration of chlorophyll a was determined and phytoplankton was microscopically examined to conduct quantitative and cluster analyses. A cluster analysis of the phytoplankton species and abundance along four observation lines revealed the three-dimensional structure of the phytoplankton community distribution: the coastal group in the mixed region, the offshore upper layer group preferring stable water column, and the offshore lower layer group. The subsurface maximum of phytoplankton abundance and chlorophyll a concentration appeared as far as 64 km away from the tidal front through the middle layer intrusion. The phytoplankton abundance was high in the shore side of tidal front during the spring tide. The phytoplankton abundance was relatively high at 10-m depth in the mixed region while the concentration of chlorophyll a was high below the depth. The disparity between the profiles of the phytoplankton abundance and the chlorophyll a concentration in the mixed region was related to the depth-dependent species change accompanied by size-fraction of the phytoplankton community. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of anthocyanin and carotenoid combinations on foliage and immature fruit color of Capsicum annuum L.

PubMed

Lightbourn, Gordon J; Griesbach, Robert J; Novotny, Janet A; Clevidence, Beverly A; Rao, David D; Stommel, John R

2008-01-01

Shades ranging from violet to black pigmentation in pepper (Capsicum annuum L.) are attributed to anthocyanin accumulation. High-performance liquid chromatography and mass spectrometry analysis of violet and black fruit tissue identified a single anthocyanin that was determined to be delphinidin-3-p-coumaroyl-rutinoside-5-glucoside. Leaf tissue of a black-pigmented foliage genotype contained the same anthocyanin found in fruit but at a considerably higher concentration in comparison to violet and black fruit tissue. Fruit chlorophyll concentration was approximately 14-fold higher in black fruit in comparison to violet fruit that contained relatively little chlorophyll. Beta-carotene, lutein, violaxanthin, and neoxanthin carotenoid concentrations in black fruit were also significantly greater in comparison to violet fruit. High concentrations of delphinidin in combination with chlorophyll and accessory carotenoid pigments produced the characteristic black pigmentation observed in fruits and leaves of selected genotypes. Anthocyanins were accumulated in the outer mesocarp of violet and black fruit and in the palisade and mesophyll cells of black leaves. Consistent with chlorophyll content of respective genotypes, chloroplast density was greater in cells of black fruits. Utilizing Capsicum pigment variants, we determine the biochemical factors responsible for violet versus black-pigmented pepper tissue in the context of described pepper color genes.

Connecting the Dots: Responses of Coastal Ecosystems to Changing Nutrient Concentrations

PubMed Central

2011-01-01

Empirical relationships between phytoplankton biomass and nutrient concentrations established across a wide range of different ecosystems constitute fundamental quantitative tools for predicting effects of nutrient management plans. Nutrient management plans based on such relationships, mostly established over trends of increasing rather than decreasing nutrient concentrations, assume full reversibility of coastal eutrophication. Monitoring data from 28 ecosystems located in four well-studied regions were analyzed to study the generality of chlorophyll a versus nutrient relationships and their applicability for ecosystem management. We demonstrate significant differences across regions as well as between specific coastal ecosystems within regions in the response of chlorophyll a to changing nitrogen concentrations. We also show that the chlorophyll a versus nitrogen relationships over time constitute convoluted trajectories rather than simple unique relationships. The ratio of chlorophyll a to total nitrogen almost doubled over the last 30–40 years across all regions. The uniformity of these trends, or shifting baselines, suggest they may result from large-scale changes, possibly associated with global climate change and increasing human stress on coastal ecosystems. Ecosystem management must, therefore, develop adaptation strategies to face shifting baselines and maintain ecosystem services at a sustainable level rather than striving to restore an ecosystem state of the past. PMID:21958109

Environmental factors associated with long-term changes in chlorophyll concentration in the Sacramento-San Joaquin delta and Suisun Bay, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehman, P.W.

Long-term changes in chlorophyll concentration were predicted from environmental variables using Box-Jenkins transfer function models for the Sacramento and San Joaquin rivers and Suisun Bay. The indication that oceanic phytoplankton biomass for the California regions is associated with climatic phenomena produced by El Nino and the Southern Oscillation (ENSO) was one of several factors used to standardize the dataset. Data used for the analyses were collected continuously on a semimonthly or monthly basis over the 17-yr period between 1971 and 1987. Groups of highly correlated environmental variables were summarized along three environmental axes using principal component analysis. The first environmentalmore » axis summarized river flow and specific conductance. The second environmental axis summarized water transparency and the third environmental axis summarized air and water temperature. Chlorophyll concentration was significantly cross-correlated with environmental axes and individual environmental variables. Transfer function models developed to describe changes in chlorophyll concentration over time were characterized by lag responses and described between 41% and 51% of the data variation. Significant cross-correlations between environmental axes and the California climate index (CA SLP) were used to develop a conceptual model of the link between regional climate and estuarine production. 50 refs., 5 figs.« less

Decadal Changes in Global Ocean Chlorophyll

NASA Technical Reports Server (NTRS)

Gregg, Watson W.; Conkright, Margarita E.; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

The global ocean chlorophyll archive produced by the Coastal Zone Color Scanner (CZCS) was revised using compatible algorithms with the Sea-viewing Wide Field-of-view Sensor (SeaWIFS), and both were blended with in situ data. This methodology permitted a quantitative comparison of decadal changes in global ocean chlorophyll from the CZCS (1979-1986) and SeaWiFS (Sep. 1997-Dec. 2000) records. Global seasonal means of ocean chlorophyll decreased over the two observational segments, by 8% in winter to 16% in autumn. Chlorophyll in the high latitudes was responsible for most of the decadal change. Conversely, chlorophyll concentrations in the low latitudes increased. The differences and similarities of the two data records provide evidence of how the Earth's climate may be changing and how ocean biota respond. Furthermore, the results have implications for the ocean carbon cycle.

Sampling Biases in MODIS and SeaWiFS Ocean Chlorophyll Data

NASA Technical Reports Server (NTRS)

Gregg, Watson W.; Casey, Nancy W.

2007-01-01

Although modem ocean color sensors, such as MODIS and SeaWiFS are often considered global missions, in reality it takes many days, even months, to sample the ocean surface enough to provide complete global coverage. The irregular temporal sampling of ocean color sensors can produce biases in monthly and annual mean chlorophyll estimates. We quantified the biases due to sampling using data assimilation to create a "truth field", which we then sub-sampled using the observational patterns of MODIS and SeaWiFS. Monthly and annual mean chlorophyll estimates from these sub-sampled, incomplete daily fields were constructed and compared to monthly and annual means from the complete daily fields of the assimilation model, at a spatial resolution of 1.25deg longitude by 0.67deg latitude. The results showed that global annual mean biases were positive, reaching nearly 8% (MODIS) and >5% (SeaWiFS). For perspective the maximum interannual variability in the SeaWiFS chlorophyll record was about 3%. Annual mean sampling biases were low (<3%) in the midlatitudes (between -40deg and 40deg). Low interannual variability in the global annual mean sampling biases suggested that global scale trend analyses were valid. High latitude biases were much higher than the global annual means, up to 20% as a basin annual mean, and over 80% in some months. This was the result of the high solar zenith angle exclusion in the processing algorithms. Only data where the solar angle is <75deg are permitted, in contrast to the assimilation which samples regularly over the entire area and month. High solar zenith angles do not facilitate phytoplankton photosynthesis and consequently low chlorophyll concentrations occurring here are missed by the data sets. Ocean color sensors selectively sample in locations and times of favorable phytoplankton growth, producing overestimates of chlorophyll. The biases derived from lack of sampling in the high latitudes varied monthly, leading to artifacts in the apparent seasonal cycle from ocean color sensors. A false secondary peak in chlorophyll occurred in May-August, which resulted from lack of sampling in the Antarctic.

Responses of Pseudokirchneriella subcapitata and algal assembly to photocatalytic titanium dioxide nanoparticles

NASA Astrophysics Data System (ADS)

Metzler, David M.

Development and use of nanomaterials has increased significantly over the past decade. This trend is expected to continue for the foreseeable future, which have led some to call this new industrial revolution. One aspect of these materials that make them special is their unique properties that are different from the bulk material. These unique properties have not been investigated to determine to what extent they will impact the environment. This work was undertaken to understand how nanoparticles could impact algae. For the determination of nanoparticle toxicity, dose-response experiments were run for similar sized Al2O3, TiO2, and SiO2. Additional, a wide range of nanoparticle sizes (d1) were tested at 100 and 1000 mg/L for Al2O3, TiO 2, and SiO2. Results of different nanoparticles and similar d1 dose-response data show increased toxicity with increased surface charge of the nanoparticle. Various d1 of Al2O 3 effect the population and chlorophyll a but not lipid peroxidation. Various d1 of SiO2 and TiO2 effect the population, chlorophyll a, and lipid peroxidation. Of all TiO2 d1 tested 42 nm had the greatest effect on population, chlorophyll a, and lipid peroxidation. The effect of light intensity, algal age, and body burden was examined. The body burden was adjusted by varying the initial algal cell population while keeping the nanoparticle concentration constant. Decreased body burden decreased the effect on population. The chlorophyll a and lipid peroxidation varied with the initial decreased with decreased body burden. This trend was reversed at low body burden, the chlorophyll a and lipid peroxidation increased 3 -- 4 times greater than control values. The algal cell age was controlled by the hydraulic retention time of the pre-exposure continuously stirred tank reactors. As the age of the algae increased the effect of population increased. At algae age great then 10 days the effect on population reminded constant. Titanium dioxide effect on chlorophyll a varied with algal age and TiO 2 concentration. Finally, the effect of light intensity was examined for both visible and UV wavelengths. The greatest effect was for 1000 mg/L of TiO2 under varying light. Peak maximums occurred for chlorophyll a and lipid peroxidation. Peak minimums occurred for population. Varying UV light intensity resulted in decreased population for 100 and 1000 mg/L of TiO2. Additionally, chlorophyll a reached a maximum at 17 and 5 x the control values under 66% UV light for 100 and 1000 mg/L of TiO 2, respectively. The effect of copper and phenol to P. subcapitata was examined in the presence of TiO2. Copper in the presence of TiO 2 increased both chlorophyll a and lipid peroxidation greater than in the presence of TiO2 alone. Optimum conditions were observed for both endpoints. When algae were exposed to Cu and TiO2 the compounds acted independently of each other, having an additive effect on population. The TiO2 acted as a protective barrier against phenol toxicity at low phenol concentrations. At high phenol concentrations the toxicity of both phenol and TiO2 increased. Both compounds acted to disrupt the cell wall stability as seen with microscopy imaging. This was presumed to be through destruction of the Ca-pectinate within the cell wall, as indicated by increased soluble Ca correlated with phenol concentrations. The effect of TiO2 on cell barriers and natural algal assemblage was investigated. SEM images reveal that algae exposed to TiO2 have DNA external to the cell. Under hypotonic stress the loss of electrolytes was less controlled when the total number of nanoparticles was 1010 in the sample, at d1 less than 46 nm. At d1 greater than 46 nm no effect on electrolyte regulation was noted. Natural algal assemblages exposed to TiO2 varied there fatty acid (FA) content. This could be due to selective growth resistant reactive oxygen species (ROS) organisms or the percentages of certain FAs were decreased because of sensitivity to ROS. (Abstract shortened by UMI.)

Root-shoot interaction in the greening of wheat seedlings grown under red light

NASA Technical Reports Server (NTRS)

Tripathy, B. C.; Brown, C. S.

1995-01-01

Wheat seedlings grown with roots exposed to constant red light (300-500 micromoles m-2 s-1) did not accumulate chlorophyll in the leaves. In contrast, seedlings grown with their roots shielded from light accumulated chlorophylls. Chlorophyll biosynthesis could be induced in red-light-grown chlorophyll-deficient yellow plants by either reducing the red-light intensity at the root surface to 100 micromoles m-1 s-1 or supplementing with 6% blue light. The inhibition of chlorophyll biosynthesis was due to impairment of the Mg-chelatase enzyme working at the origin of the Mg-tetrapyrrole pathway. The root-perceived photomorphogenic inhibition of shoot greening demonstrates root-shoot interaction in the greening process.

Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes

USGS Publications Warehouse

Filstrup, Christopher T.; Wagner, Tyler; Soranno, Patricia A.; Stanley, Emily H.; Stow, Craig A.; Webster, Katherine E.; Downing, John A.

2014-01-01

The relationship between chlorophyll a (Chl a) and total phosphorus (TP) is a fundamental relationship in lakes that reflects multiple aspects of ecosystem function and is also used in the regulation and management of inland waters. The exact form of this relationship has substantial implications on its meaning and its use. We assembled a spatially extensive data set to examine whether nonlinear models are a better fit for Chl a—TP relationships than traditional log-linear models, whether there were regional differences in the form of the relationships, and, if so, which regional factors were related to these differences. We analyzed a data set from 2105 temperate lakes across 35 ecoregions by fitting and comparing two different nonlinear models and one log-linear model. The two nonlinear models fit the data better than the log-linear model. In addition, the parameters for the best-fitting model varied among regions: the maximum and lower Chl aasymptotes were positively and negatively related to percent regional pasture land use, respectively, and the rate at which chlorophyll increased with TP was negatively related to percent regional wetland cover. Lakes in regions with more pasture fields had higher maximum chlorophyll concentrations at high TP concentrations but lower minimum chlorophyll concentrations at low TP concentrations. Lakes in regions with less wetland cover showed a steeper Chl a—TP relationship than wetland-rich regions. Interpretation of Chl a—TP relationships depends on regional differences, and theory and management based on a monolithic relationship may be inaccurate.

Quantifying Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems

PubMed Central

Gove, Jamison M.; Williams, Gareth J.; McManus, Margaret A.; Heron, Scott F.; Sandin, Stuart A.; Vetter, Oliver J.; Foley, David G.

2013-01-01

Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic–biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change. PMID:23637939

Quantifying climatological ranges and anomalies for Pacific coral reef ecosystems.

PubMed

Gove, Jamison M; Williams, Gareth J; McManus, Margaret A; Heron, Scott F; Sandin, Stuart A; Vetter, Oliver J; Foley, David G

2013-01-01

Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic-biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change.

Cost-effective water quality assessment through the integration of monitoring data and modeling results

NASA Astrophysics Data System (ADS)

Lobuglio, Joseph N.; Characklis, Gregory W.; Serre, Marc L.

2007-03-01

Sparse monitoring data and error inherent in water quality models make the identification of waters not meeting regulatory standards uncertain. Additional monitoring can be implemented to reduce this uncertainty, but it is often expensive. These costs are currently a major concern, since developing total maximum daily loads, as mandated by the Clean Water Act, will require assessing tens of thousands of water bodies across the United States. This work uses the Bayesian maximum entropy (BME) method of modern geostatistics to integrate water quality monitoring data together with model predictions to provide improved estimates of water quality in a cost-effective manner. This information includes estimates of uncertainty and can be used to aid probabilistic-based decisions concerning the status of a water (i.e., impaired or not impaired) and the level of monitoring needed to characterize the water for regulatory purposes. This approach is applied to the Catawba River reservoir system in western North Carolina as a means of estimating seasonal chlorophyll a concentration. Mean concentration and confidence intervals for chlorophyll a are estimated for 66 reservoir segments over an 11-year period (726 values) based on 219 measured seasonal averages and 54 model predictions. Although the model predictions had a high degree of uncertainty, integration of modeling results via BME methods reduced the uncertainty associated with chlorophyll estimates compared with estimates made solely with information from monitoring efforts. Probabilistic predictions of future chlorophyll levels on one reservoir are used to illustrate the cost savings that can be achieved by less extensive and rigorous monitoring methods within the BME framework. While BME methods have been applied in several environmental contexts, employing these methods as a means of integrating monitoring and modeling results, as well as application of this approach to the assessment of surface water monitoring networks, represent unexplored areas of research.

Black Sea spectral bio-optical models based on satellite data and their applications for assessment of spatial and temporal variability in waters transparency, chlorophyll a content and primary production

NASA Astrophysics Data System (ADS)

Churilova, T.; Suslin, V.

2012-04-01

Satellite observations of ocean color provide a unique opportunity in oceanography to assess productivity of the sea on different spatial and temporal scales. However it has been shown that the standard SeaWiFS algorithm generally overestimates summer chlorophyll concentration and underestimates pigment content during spring phytoplankton bloom in comparison with in situ measurements. It is required to develop regional algorithms which are based on biooptical characteristics typical for the Sea and consequently could be used for correct transformation of spectral features of water-leaving radiance to chlorophyll a concentrations (Chl), light absorption features of suspended and dissolved organic matter (CDM), downwelling light attenuation coefficient/euphotic zone depth (PAR1%) and rate of primary synthesis of organic substances (PP). The numerous measurements of light absorption spectra of phytoplankton, non-algal particles and coloured dissolved organic matter carried out since 1996 in different seasons and regions of the Black Sea allowed to make a parameterization of the light absorption by all optically active components. Taking into account regional peculiarities of the biooptical parameters, their difference between seasons, shallow and deep-waters, their depth-dependent variability within photosynthetic zone regional spectral models for estimation of chlorophyll a concentration (Chl Model), colored dissolved and suspended organic matter absorption (CDM Model), downwelling irradiance (PAR Model) and primary production (PP Model) have been developed based on satellite data. Test of validation of models showed appropriate accuracy of the models. The developed models have been applied for estimation of spatial/temporal variability of chlorophyll a, dissolved organic matter concentrations, waters transparency, euphotic zone depth and primary production based on SeaWiFS data. Two weeks averaged maps of spatial distribution of these parameters have been composed for period from 1998 to 2009 (most of them presented on site http://blackseacolor.com/browser3.html). Comparative analysis of long-term series (since 1998) of these parameters with subsurface water temperature (SST) and solar radiance of the sea surface (PAR-0m) revealed the key factors determining the seasonal and inter-annual variations of Chl, PAR1%, CDM, PP. The seasonal dynamics of these parameters were more pronounced compared with inter-annual variability. The later was related to climate effect. In deep-waters region relatively lower SST during cold winters were forcing more intensive winter-spring phytoplankton bloom. In north-western shelf inter-annual variability in river (Danube) run off, which was related to climate change as well, determined year-to-year changing in Chl, CDM, PAR1%, and PP.

The Use of a Chlorophyll Meter (SPAD-502) for Field Determinations of Red Mangrove (Rhizophora Mangle L.) Leaf Chlorophyll Amount

NASA Technical Reports Server (NTRS)

Connelly, Xana M.

1997-01-01

The red mangrove Rhizophora mangle L., is a halophytic woody spermatophyte common to the land-sea interface of tropical and subtropical intertidal zones. It has been reported that 60 to 75% of the coastline of the earth's tropical regions are lined with mangroves. Mangroves help prevent shoreline erosion, provide breeding, nesting and feeding areas for many marine animals and birds. Mangroves are important contributors of primary production in the coastal environment, and this is largely proportional to the standing crop of leaf chlorophylls. Higher intensities of ultraviolet radiation, resulting from stratospheric ozone depletion, can lead to a reduction of chlorophyll in terrestrial plants. Since the most common method for determining chlorophyll concentration is by extraction and this is labor intensive and time consuming, few studies on photosynthetic pigments of mangroves have been reported. Chlorophyll meter readings have been related to leaf chlorophyll content in apples and maples. It has also been correlated to nitrogen status in corn and cotton. Peterson et al., (1993) used a chlorophyll meter to detect nitrogen deficiency in crops and in determining the need for additional nitrogen fertilizer. Efforts to correlate chlorophyll meter measurements to chlorophyll content of mangroves have not been reported. This paper describes the use of a hand-held chlorophyll meter (Minolta SPAD-502) to determine the amount of red mangrove foliar chlorophyll present in the field.

Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea

NASA Astrophysics Data System (ADS)

Hoppe, H.-G.; Giesenhagen, H. C.; Koppe, R.; Hansen, H.-P.; Gocke, K.

2013-07-01

Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the conversion of the political system in the southern and eastern border states, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, bacteria number, bacterial biomass and bacterial production, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. Strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen, even in the surface layer, was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. The long-term seasonal patterns of all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables (as well as precipitation) and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll, which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ -60%), followed by chlorophyll (-50%) and bacterial biomass (-40%). Considering the circulation of surface currents in the Baltic Sea we interpret the observed patterns of the microbial variables at the Boknis Eck time series station as a consequence of the improved management of water resources after 1989 and - to a minor extent - the trends of the climate variables salinity and temperature.

Impact of change in climate and policy from 1988 to 2007 on environmental and microbial variables at the time series station Boknis Eck, Baltic Sea

NASA Astrophysics Data System (ADS)

Hoppe, H.-G.; Giesenhagen, H. C.; Koppe, R.; Hansen, H.-P.; Gocke, K.

2012-12-01

Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the Western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the collapse and conversion of the political system in the Southern and Eastern Border States, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, the bacterial variables, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. The strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen even in the surface layer was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. In the long run all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables as well as precipitation and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ -60%), followed by chlorophyll (-50%) and bacterial biomass (-40%). Considering the circulation of surface currents in the Baltic Sea we conclude that the improved management of water resources after 1989 together with the trends of the climate variables salinity and temperature were responsible for the observed patterns of the microbial variables at the Boknis Eck time series station.

[Baseline correction of spectrum for the inversion of chlorophyll-a concentration in the turbidity water].

PubMed

Wei, Yu-Chun; Wang, Guo-Xiang; Cheng, Chun-Mei; Zhang, Jing; Sun, Xiao-Peng

2012-09-01

Suspended particle material is the main factor affecting remote sensing inversion of chlorophyll-a concentration (Chla) in turbidity water. According to the optical property of suspended material in water, the present paper proposed a linear baseline correction method to weaken the suspended particle contribution in the spectrum above turbidity water surface. The linear baseline was defined as the connecting line of reflectance from 450 to 750 nm, and baseline correction is that spectrum reflectance subtracts the baseline. Analysis result of field data in situ of Meiliangwan, Taihu Lake in April, 2011 and March, 2010 shows that spectrum linear baseline correction can improve the inversion precision of Chl a and produce the better model diagnoses. As the data in March, 2010, RMSE of band ratio model built by original spectrum is 4.11 mg x m(-3), and that built by spectrum baseline correction is 3.58 mg x m(-3). Meanwhile, residual distribution and homoscedasticity in the model built by baseline correction spectrum is improved obviously. The model RMSE of April, 2011 shows the similar result. The authors suggest that using linear baseline correction as the spectrum processing method to improve Chla inversion accuracy in turbidity water without algae bloom.

[Semi-analysis algorithm to retrieve pigment concentrations in the red tide area of the East China Sea].

PubMed

Qiu, Zhong-Feng; Xi, Hong-Yan; He, Yi-Jun; Chen, Jay-Chung; Jian, Wei-Jun

2006-08-01

For the purpose of detecting and forecasting research of red tides to reduce the loss, a semi-analytic algorithm to retrieve chlorophyll-a concentrations was established in the area where red tides often brought out, according to the data collected during the red tides cruise in the East China Sea in April 2002. In the algorithm, empirical equations were made based on the coefficients from the in-situ data, including the optical properties of the research area. The in-situ data were used to validate the algorithm. The discrepancy of chlorophyll-a absorption coefficients and concentrations are mainly located in the region of 30%. The root mean deviation of the chlorophyll-a concentrations between the observed and the calculated is 0.24, the maximum relative deviation 40.93%, the mean relative deviation 18.83% and the correlation coefficient 0.83. The results show that the precision of the algorithm is high and the algorithm is fit for the research area.

Impact of Submesoscale Processes on Dynamics of Phytoplankton Filaments

DTIC Science & Technology

2015-02-12

submesoscale processes on the formation of chlorophyll a filaments during late springearlier summer, and late summer time frames. We show that during...the late summer time frame, ASC leads to the development of filaments with high values of chlorophyll a concentration along the edge of the cold jet...in contrast to the earlier summer time, when the ASC mixes phytoplankton much deeper to the area below of the euphotic depth, and chlorophyll a

Sensitivity of Calibration Gains to Ocean Color Processing in Coastal and Open Waters Using Ensembles Members for NPP-VIIRS

DTIC Science & Technology

2014-07-01

a different impact on spectral normalized water leaving radiances and the derived ocean color products (inherent optical properties, chlorophyll ). We...leaving radiances and the derived ocean color products (inherent optical properties, chlorophyll ). We evaluated the influence of gains from open and...34gain" on ocean color products. These products include the spectral Remote Sensing Reflectance (RRS), chlorophyll concentration, and Inherent Optical

Temperature-Correlated Changes in Phytoplankton Community Structure Are Restricted to Polar Waters.

PubMed

Ward, Ben A

2015-01-01

Globally distributed observations of size-fractionated chlorophyll a and temperature were used to incorporate temperature dependence into an existing semi-empirical model of phytoplankton community size structure. The additional temperature-dependent term significantly increased the model's ability to both reproduce and predict observations of chlorophyll a size-fractionation at temperatures below 2°C. The most notable improvements were in the smallest (picoplankton) size-class, for which overall model fit was more than doubled, and predictive skill was increased by approximately 40%. The model was subsequently applied to generate global maps for three phytoplankton size classes, on the basis of satellite-derived estimates of surface chlorophyll a and sea surface temperature. Polar waters were associated with marked decline in the chlorophyll a biomass of the smallest cells, relative to lower latitude waters of equivalent total chlorophyll a. In the same regions a complementary increase was seen in the chlorophyll a biomass of larger size classes. These findings suggest that a warming and stratifying ocean will see a poleward expansion of the habitat range of the smallest phytoplankton, with the possible displacement of some larger groups that currently dominate. There was no evidence of a strong temperature dependence in tropical or sub-tropical regions, suggesting that future direct temperature effects on community structure at lower latitudes may be small.

Impact of the river Liffey discharge on nutrient and chlorophyll concentrations in the Liffey estuary and Dublin Bay (Irish Sea)

NASA Astrophysics Data System (ADS)

O'Higgins, T. G.; Wilson, J. G.

2005-08-01

Temperature, salinity, nutrients (total oxidised nitrogen (TON), ammonium (NH 4) and orthophosphate (PO 4)) and chlorophyll a were monitored in the Liffey estuary and Dublin Bay from June 2000 to June 2003. Four groups of sites were defined comprising the upper estuary (Gp. I), the outer estuary (Gp. III) with a small set (Gp. II) of sites between Groups I and III heavily influenced by the sewage treatment works outflow, and the Bay proper (Gp. IV). Riverine inputs of TON and PO 4 were calculated at an average of 826 t N y -1 and 31 t P y -1, respectively, and were largely controlled by flow rate. The sewage treatment works were identified as a major source of PO 4 and NH 4 to the system. Mixing in the upper estuary of nutrient limited saline waters with hypernutrified river water regularly (i.e. annually) produced relatively high concentrations of chlorophyll a (>10 mg chl a m -3), and also sporadic blooms with extremely high chlorophyll a values (max. 121.6 mg chl a m -3). These latter phytoplankton blooms occurred in high salinity waters and were due to mixing of nutrient limited saline waters and nutrient rich river waters. The mean annual flux of phytoplankton carbon from the river Liffey was calculated at 23.5 t C y -1, of which half was accumulated or remineralised in the estuary and did not enter the Bay. In the Bay proper (Gp. IV) summer nutrient concentrations dropped below detection limits, and chlorophyll a concentrations followed the classic pattern with a spring bloom maximum of 5.5 mg chl a m -3. This pattern in nutrients and chlorophyll a came from the advection of waters into the Bay from an offshore source. Overall while there was considerable evidence for eutrophication in the estuary, the bay itself showed little biological response to nutrient loading.

Assessing the Variability in the Relationship Between the Particulate Backscattering Coefficient and the Chlorophyll a Concentration From a Global Biogeochemical-Argo Database

NASA Astrophysics Data System (ADS)

Barbieux, Marie; Uitz, Julia; Bricaud, Annick; Organelli, Emanuele; Poteau, Antoine; Schmechtig, Catherine; Gentili, Bernard; Obolensky, Grigor; Leymarie, Edouard; Penkerc'h, Christophe; D'Ortenzio, Fabrizio; Claustre, Hervé

2018-02-01

Characterizing phytoplankton distribution and dynamics in the world's open oceans requires in situ observations over a broad range of space and time scales. In addition to temperature/salinity measurements, Biogeochemical-Argo (BGC-Argo) profiling floats are capable of autonomously observing at high-frequency bio-optical properties such as the chlorophyll fluorescence, a proxy of the chlorophyll a concentration (Chla), the particulate backscattering coefficient (bbp), a proxy of the stock of particulate organic carbon, and the light available for photosynthesis. We analyzed an unprecedented BGC-Argo database of more than 8,500 multivariable profiles collected in various oceanic conditions, from subpolar waters to subtropical gyres. Our objective is to refine previously established Chla versus bbp relationships and gain insights into the sources of vertical, seasonal, and regional variability in this relationship. Despite some regional, seasonal and vertical variations, a general covariation occurs at a global scale. We distinguish two main contrasted situations: (1) concomitant changes in Chla and bbp that correspond to actual variations in phytoplankton biomass, e.g., in subpolar regimes; (2) a decoupling between the two variables attributed to photoacclimation or changes in the relative abundance of nonalgal particles, e.g., in subtropical regimes. The variability in the bbp:Chla ratio in the surface layer appears to be essentially influenced by the type of particles and by photoacclimation processes. The large BGC-Argo database helps identifying the spatial and temporal scales at which this ratio is predominantly driven by one or the other of these two factors.

Coincident patterns of waste water suspended solids reduction, water transparency increase and chlorophyll decline in Narragansett Bay.

PubMed

Borkman, David G; Smayda, Theodore J

2016-06-15

Dramatic changes occurred in Narragansett Bay during the 1980s: water clarity increased, while phytoplankton abundance and chlorophyll concentration decreased. We examine how changes in total suspended solids (TSS) loading from wastewater treatment plants may have influenced this decline in phytoplankton chlorophyll. TSS loading, light and phytoplankton observations were compiled and a light- and temperature-dependent Skeletonema-based phytoplankton growth model was applied to evaluate chlorophyll supported by TSS nitrogen during 1983-1995. TSS loading declined 75% from ~0.60×10(6)kgmonth(-1) to ~0.15×10(6)kgmonth(-1) during 1983-1995. Model results indicate that nitrogen reduction related to TSS reduction was minor and explained a small fraction (~15%) of the long-term chlorophyll decline. The decline in NBay TSS loading appears to have increased water clarity and in situ irradiance and contributed to the long-term chlorophyll decline by inducing a physiological response of a ~20% reduction in chlorophyll per cell. Copyright © 2016 Elsevier Ltd. All rights reserved.

On the "hidden" phytoplankton blooms on Australia's southern shelves

NASA Astrophysics Data System (ADS)

Kämpf, Jochen; Kavi, Ankit

2017-02-01

Phytoplankton blooms on Australia's southern shelves are revisited using satellite-derived monthly data of chlorophyll a concentrations for the period 2003-2015. It is known that the region hosts a seasonal coastal upwelling system that develops in austral summer (January-March) with chlorophyll a concentrations of >2 mg/m3. While this summer upwelling is spatially limited to a few hot spots, here we show that widespread phytoplankton blooms of moderate ( 1 mg/m3) chlorophyll a concentrations develop during autumn and early winter on most of Australia's extensive southern shelves—from the vast shelves of the Great Australian Bight (GAB) in the west to Bass Strait in the east. This surprising finding disproves the widespread belief that shelf waters of the GAB are generally oligotrophic and may explain the relatively high abundance of both forage fish (sardines) and upper trophic-level predators (e.g., tuna and whales) in the region.

Modeling Primary Productivity in the Margin Ice Zone from Glider-Based Measurements of Chlorophyll and Light during the 2014 Miz Program

NASA Astrophysics Data System (ADS)

Perry, M. J.; Lee, C.; Rainville, L.; Cetinic, I.; Yang, E. J.; Kang, S. H.

2016-02-01

In late summer 2014 during the Marginal Ice Zone (MIZ) Experiment, an international project sponsored by ONR, four Seagliders transited open water, through the marginal ice zone, and under ice-covered regions in the Beaufort Sea, penetrating as far as 100 km into the ice pack. The gliders navigated either by GPS in open water or, when under the ice, by acoustics from sound sources embedded in the MIZ autonomous observing array. The glider sensor suite included temperature, temperature microstructure, salinity, oxygen, chlorophyll fluorescence, optical backscatter, and multi-spectral downwelling irradiance. Cruises on the IBRV Araon operating in the open Beaufort Sea and on the R/V Ukpik and Norseman operating in continental shelf waters off Alaska's north slope allowed us to construct proxy libraries for converting chlorophyll fluorescence to chlorophyll concentration and optical backscatter to particulate organic carbon concentration. Water samples were collected for chlorophyll and particulate organic carbon analysis on the cruises and aligned with optical profiles of fluorescence and backscatter using sensors that were factory calibrated at the same time as the glider sensors. Fields of chlorophyll, particulate organic carbon, light, and primary productivity are constructed from the glider data. Productivity is modeled as a function of chlorophyll and light, using photosynthesis-light (PE) models with available PE parameters from Arctic measurements. During August the region under the ice was characterized by a deep chlorophyll maximum layer with low rates of production in overlying waters. A phytoplankton bloom developed in open water at the end of September, preceding the rapid reformation of ice, despite shorter days and reduce irradiation.

Surface and mid-water sources of organic carbon by photoautotrophic and chemoautotrophic production in the Black Sea

NASA Astrophysics Data System (ADS)

Yılmaz, Ayşen; Çoban-Yıldız, Yeşim; Telli-Karakoç, Fatma; Bologa, Alexandru

2006-08-01

The multilayered surface waters of the Black Sea contain aerobic, suboxic and anoxic layers that support both photoautotrophic (PP) and chemoautotrophic (ChP) biological production. During the R/V Knorr cruise in May-June 2001, phytoplankton biomass (represented as chlorophyll- a), photoautotrophic and chemoautotrophic production (ChP) rates were determined in the western Black Sea. Integrated chlorophyll- a concentrations in the euphotic zone were as low as 2.2 mg m -2 in the central gyre, while they were as high as 19.9 mg m -2 in the NW shelf region. Integrated photoautotrophic production rates ranged from 112 to 355 mg C m -2 d -1. The lowest values were determined in the central gyre and the highest values were found at the shelf-break station near the Bosphorus, the NW shelf/shelf-break area and in the Sevastopol eddy. Primary production and chlorophyll- a data revealed that post-bloom conditions existed during this sampling period. Bioassay experiments showed that under optimum light conditions, photoautotrophic production was nitrogen-limited. ChP increased in the redox transition zone and coincided with the lower boundary of the fine particle layer. The maximum values were shallower (at σθ=16.25) in the central gyre and deeper (at σθ=16.5) in the shelf-break region near Sakarya Canyon. Integrated ChP rates were 63 and 1930 mg C m -2 d -1, which were equivalent to 30% and 89% of the overall water-column production for the central gyre and Sakarya Canyon regions, respectively.

Effect of deep water nutrient enrichment on plankton metabolism in the N and S Atlantic gyres

NASA Astrophysics Data System (ADS)

Serret, P.; Jose, L.; Harris, C.; Lange, P. K.; Tarran, G.; Thomas, R.; Zubkov, M.

2016-02-01

Observations indicate that the metabolic balance in the epipelagic N and S Atlantic gyres differ as a result of regional differences in both photosynthesis (P) and respiration (R) rates. However, the trophic and biogeochemical processes causing these patterns are mostly unknown. With the aim to explore if regional differences exist in the response of epipelagic communities to nutrient enrichment, we carried out two microcosm (20L) experiments in the N (19° 51 N; 29° 08 W) and S (18° 33 S; 25° 04 W) Atlantic gyres. 1, 2, 3 and 4 L of deep (ca. 220 m depth) seawater were added to surface seawater samples (2 m depth) up to final volumes of 20L, and were incubated during 8 (N Gyre) or 5 (S gyre) days, together with untreated controls, in a deck incubator refrigerated with surface seawater. In both the N and S gyres, P and chlorophyll a concentration increased rapidly after the addition of deep seawater, especially in the pico- and nanophytoplankton. Increases in R rates were slower and smaller than for P. This changed the community metabolism from marginally heterotrophic at the beginning of the experiments (-0.32 ± 0.21, -0.19 ± 0.14 mmol O2 m-3 d-1 in the N and S gyre, respectively) to net autotrophic (up to ca. 2 and 4 mmol O2 m-3 d-1 on days 5 and 8 in the +3L and +4L treatments of the N and S gyre experiments, respectively). Here we analyze the response of community P and R rates, together with the dynamics of nutrient concentration, size-fractionated chlorophyll a concentration, and abundance of Prochlorococcus, Synechococcus, total bacteria and viruses.

Identification and quantification of Cu-chlorophyll adulteration of edible oils.

PubMed

Fang, Mingchih; Tsai, Chia-Fen; Wu, Guan-Yan; Tseng, Su-Hsiang; Cheng, Hwei-Fang; Kuo, Ching-Hao; Hsu, Che-Lun; Kao, Ya-Min; Shih, Daniel Yang-Chih; Chiang, Yu-Mei

2015-01-01

Cu-pyropheophytin a, the major Cu-pigment of Cu-chlorophyll, was determined in edible oil by high-resolution mass spectrometry with a high-performance liquid chromatography-quadrupole (HPLC-Q)-Orbitrap system and by HPLC coupled with a photodiode-array detector. Respective limit of detection and limit of quantification levels of 0.02 μg/g and 0.05 μg/g were obtained. Twenty-nine commercial oil products marked as olive oil, grapeseed oil and blended oil, all sourced directly from a food company that committed adulteration with Cu-chlorophyll, were investigated. In this company, four green dyes illegally used in oils were seized during factory investigation by the health authorities. The food additive Cu-pyropheophytin a was found in all confiscated samples in concentrations between 0.02 and 0.39 μg/g. Survey results of another 235 commercial oil samples manufactured from other companies, including olive pomace oil, extra virgin olive oil, olive oil, grapeseed oil and blended oil, indicated high positive incidences of 63%, 39%, 44%, 97% and 8%, respectively, with a concentration range between 0.02 and 0.54 μg/g. High Cu-chlorophyll concentrations are indications for fraudulent adulteration of oils.

Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile).

PubMed

Escalante, P De Los Ríos; Soto, D; Santander-Massa, R; Acevedo, P

2017-01-01

The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second with moderate chlorophyll and nutrients concentration and moderate daphnids percentage; high species number and a third site with high chlorophyll and nutrients concentration, high daphnids percentage and high species number. Daphnids increase under mesotrophic status, agree with similar results observed for southern Argentinean and New Zealand lakes.

Sugar regulation of plastid reversion in citrus epicarp is mediated through organic acid metabolism.

PubMed

Ahmed, Omer Khidir

2009-02-01

The inhibition by sucrose of chromoplast reversion to chloroplast in citrus epicarp was studied by observing the effects of several sugars, sugar metabolites and 1-iodoacetate on chlorophyll reaccumulation in cultured Citrus paradisi Macf. pericarp segments. Pericarp segments of 1 cm in diameter were cut from yellow fruits and cultured on modified medium plus the indicated metabolites and kept under continuous fluorescent light. Accumulation of chlorophyll in the segments was measured with a spectrophotometer fitted with sphere reflectometer. Respiration was determined via., an infrared gas analyzer. Inhibition of regreening was not specific to a particular sugar. The organic acids malate, citrate, succinate, 2-oxoglutarate and especially malonate elicited effects similar to sucrose, but at much lower concentrations. However, malonate inhibition of chlorophyll accumulation was overcome by increased concentrations of glutamine. At concentrations that usually inhibited chlorophyll, malonate did not reduce CO2 production in the presence of glutamine or KNO3. Sucrose effects on regreening were reduced by 1-iodoacetate. These results indicate that sugar regulation of plastid reversion during regreening in citrus epicarp is not directly due to sugars, but is instead mediated through metabolism of sugars to organic acids, especially malonic acid.

Wind-driven changes of surface current, temperature, and chlorophyll observed by satellites north of New Guinea

NASA Astrophysics Data System (ADS)

Radenac, Marie-Hélène; Léger, Fabien; Messié, Monique; Dutrieux, Pierre; Menkes, Christophe; Eldin, Gérard

2016-04-01

Satellite observations of wind, sea level and derived currents, sea surface temperature (SST), and chlorophyll are used to expand our understanding of the physical and biological variability of the ocean surface north of New Guinea. Based on scarce cruise and mooring data, previous studies differentiated a trade wind situation (austral winter) when the New Guinea Coastal Current (NGCC) flows northwestward and a northwest monsoon situation (austral summer) when a coastal upwelling develops and the NGCC reverses. This circulation pattern is confirmed by satellite observations, except in Vitiaz Strait where the surface northwestward flow persists. We find that intraseasonal and seasonal time scale variations explain most of the variance north of New Guinea. SST and chlorophyll variabilities are mainly driven by two processes: penetration of Solomon Sea waters and coastal upwelling. In the trade wind situation, the NGCC transports cold Solomon Sea waters through Vitiaz Strait in a narrow vein hugging the coast. Coastal upwelling is generated in westerly wind situations (westerly wind event, northwest monsoon). Highly productive coastal waters are advected toward the equator and, during some westerly wind events, toward the eastern part of the warm pool. During El Niño, coastal upwelling events and northward penetration of Solomon Sea waters combine to influence SST and chlorophyll anomalies.

A Simulation of Biological Prosesses in the Equatorial Pacific Warm Pool at 165 deg E

NASA Technical Reports Server (NTRS)

McClain, Charles R.; Murtugudde, Ragu; Signorini, Sergio

1998-01-01

A nine-year simulation (1984-1992) of biological processes in the equatorial Pacific Warm Pool is presented. A modified version of the 4-component (phytoplankton, zooplankton, nitrate and ammonium) ecosystem model by McClain et al. (1996) is used. Modifications include use of a spectral model for computation of PAR and inclusion of fecal pellet remineralization and ammonium nitrification. The physical parameters (horizontal and vertical velocities and temperature) required by the ecosystem model were derived from an improved version of the Gent and Cane (1990) ocean general circulation model (Murtugudde and Busalacchi, 1997). Surface downwelling spectral irradiance was estimated using the clear-sky models of Frouin et al. (1989) and Gregg and Carder (1990) and cloud cover information from the International Satellite Cloud Climatology Project (ISCCP). The simulations indicate considerable variability on interannual time scales in all four ecosystem components. In particular, surface chlorophyll concentrations varied by an order of magnitude with maximum values exceeding 0.30 mg/cu m in 1988, 1989, and 1990, and pronounced minimums during 1987 and 1992. The deep chlorophyll maximum ranged between 75 and 125 meters with values occasionally exceeding 0.40 mg/cu m. With the exception of the last half of 1988, surface nitrate was always near depletion. Ammonium exhibited a subsurface maximum just below the DCM with concentrations as high as 0.5 mg-atN/cu m . Total integrated annual primary production varied between 40 and 250 gC/sq m/yr with an annual average of 140 gC/sq m/yr. Finally, the model is used to estimate the mean irradiance at the base of the mixed layer, i.e., the penetration irradiance, which was 18 Watts/sq m over the nine year period. The average mixed layer depth was 42 m.

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

NASA Astrophysics Data System (ADS)

Rembauville, M.; Meilland, J.; Ziveri, P.; Schiebel, R.; Blain, S.; Salter, I.

2016-05-01

We report the contribution of planktic foraminifers and coccoliths to the particulate inorganic carbon (PIC) export fluxes collected over an annual cycle (October 2011/September 2012) on the central Kerguelen Plateau in the Antarctic Zone (AAZ) south of the Polar Front (PF). The seasonality of PIC flux was decoupled from surface chlorophyll a concentration and particulate organic carbon (POC) fluxes and was characterized by a late summer (February) maximum. This peak was concomitant with the highest satellite-derived sea surface PIC and corresponded to a Emiliania huxleyi coccoliths export event that accounted for 85% of the annual PIC export. The foraminifer contribution to the annual PIC flux was much lower (15%) and dominated by Turborotalita quinqueloba and Neogloboquadrina pachyderma. Foraminifer export fluxes were closely related to the surface chlorophyll a concentration, suggesting food availability as an important factor regulating the foraminifer's biomass. We compared size-normalized test weight (SNW) of the foraminifers with previously published SNW from the Crozet Islands using the same methodology and found no significant difference in SNW between sites for a given species. However, the SNW was significantly species-specific with a threefold increase from T. quinqueloba to Globigerina bulloides. The annual PIC:POC molar ratio of 0.07 was close to the mean ratio for the global ocean and lead to a low carbonate counter pump effect (~5%) compared to a previous study north of the PF (6-32%). We suggest that lowers counter pump effect south of the PF despite similar productivity levels is due to a dominance of coccoliths in the PIC fluxes and a difference in the foraminifers species assemblage with a predominance of polar species with lower SNW.

Validation Test Report for the BioCast Optical Forecast Model Version 1.0

DTIC Science & Technology

2015-04-09

can generate such as: total absorption (a), backscattering (bb), chlorophyll (chl), sea surface temperature (SST), diver visibility, etc. The...optical backscattering coefficient BSP - Battle Space Profiler CHARTS - Compact Hydrographic Airborne Rapid Total Survey Chl - Chlorophyll EO

Green and non-green callus induction from excised rice (Oryza sativa) embryos: effects of exogenous plant growth regulators

NASA Technical Reports Server (NTRS)

Kim, D.; Brock, T. G.; Kaufman, P. B.

1992-01-01

Calli were induced either from excised rice embryos or from whole seeds in the presence of 1 to 5 mg l-1 NAA. After 12 days of culture, calli were induced only from excised rice embryos. We found that excised embryos accumulated NAA up to 6 times higher concentration than did whole seeds. In the presence of 1 to 5 mg l-1 NAA and 2 to 10 mg l-1 kinetin, chlorophyllous calli were induced from excised rice embryos. Chlorophyll contents in the callus tissue increased with increasing kinetin concentration while percent callus induction decreased. The total chlorophyll content was linearly correlated with the ratio of kinetin to NAA in the medium.

Study on the change law of hyperspectral data and pigments for rice in mature process

NASA Astrophysics Data System (ADS)

Huang, Jingfeng; Tang, Yanlin; Wang, Renchao

2004-01-01

The hyperspectral reflectances of the canopy, the sword leaf, the third unfolding leaf from the top and ear of the main stem of two varieties of rice are measured by a ASD FieldSpec Pro FR in field and indoor under 3 nitrogen support levels in mature process. The concentrations of chlorophyll and carotenoid of leaves and ears corresponding to the spectra were determined by biochemical method. The spectral differences are significant for the canopy and leaves of rice under differet nitrogen support level, and the concentrations of chlorophyll and carotenoid of leaves increase with the increasing of nitrogen applying. There exist significant differences for the pigment concentrations of the leaves of rice under different nitrogen levels. The spectral reflectances of the canopy are gradually getting bigger in the visible region and smaller in the near infrared region as the growth stage goes on. 'Blue shift' phenomena for the spectra red edge position of the canopy, leaves and ears were proved. The concentrations of chlorophyll and carotenoid of leaves and ears are very significantly correlative to the spectral vegetation indices VI1(= R990/R553), VI2(=R1200/R553), VI3(=R750/R553), VI4(=R670/R440), VI5(= R553/R670), PRVI(=R800/R553), PSSRa, PSNDa and λred (the red edge position). The results show that these VIs can be used to estimate the concentrations of chlorophyll and carotenoid of leaves and ears of rice.

Eutrophication and Warming Boost Cyanobacterial Biomass and Microcystins.

PubMed

Lürling, Miquel; van Oosterhout, Frank; Faassen, Elisabeth

2017-02-11

Eutrophication and warming are key drivers of cyanobacterial blooms, but their combined effects on microcystin (MC) concentrations are less studied. We tested the hypothesis that warming promotes cyanobacterial abundance in a natural plankton community and that eutrophication enhances cyanobacterial biomass and MC concentrations. We incubated natural seston from a eutrophic pond under normal, high, and extreme temperatures (i.e., 20, 25, and 30 °C) with and without additional nutrients added (eutrophication) mimicking a pulse as could be expected from projected summer storms under climate change. Eutrophication increased algal- and cyanobacterial biomass by 26 and 8 times, respectively, and led to 24 times higher MC concentrations. This effect was augmented with higher temperatures leading to 45 times higher MC concentrations at 25 °C, with 11 times more cyanobacterial chlorophyll- a and 25 times more eukaryote algal chlorophyll- a . At 30 °C, MC concentrations were 42 times higher, with cyanobacterial chlorophyll- a being 17 times and eukaryote algal chlorophyll- a being 24 times higher. In contrast, warming alone did not yield more cyanobacteria or MCs, because the in situ community had already depleted the available nutrient pool. MC per potential MC producing cell declined at higher temperatures under nutrient enrichments, which was confirmed by a controlled experiment with two laboratory strains of Microcystis aeruginosa. Nevertheless, MC concentrations were much higher at the increased temperature and nutrient treatment than under warming alone due to strongly promoted biomass, lifting N-imitation and promotion of potential MC producers like Microcystis . This study exemplifies the vulnerability of eutrophic urban waters to predicted future summer climate change effects that might aggravate cyanobacterial nuisance.

Salinity, Temperature, and Optical Characterization of a Tidally Choked Estuary Connected to Two Contrasting Intra-Coastal Waterways

DTIC Science & Technology

2013-06-01

phytoplankton production, and hence chlorophyll a concentration. As a result, light absorption in coastal waters is dominated by CDOM, while light ...water influence in the ocean and to track river plumes in open water (Chen 1999). In one particular case, the addition of chlorophyll a fluorescence...matter (CDOM) (Chen 1999) that consists of the humic and fluvic acids (yellow substance) of decaying plant matter (Nieke et al. 1997). Like chlorophyll

Morphological and biochemical changes in Azadirachta indica from coal combustion fly ash dumping site from a thermal power plant in Delhi, India.

PubMed

Qadir, Sami Ullah; Raja, Vaseem; Siddiqui, Weqar A

2016-07-01

The foliar and biochemical traits of Azadirachta indica A. Juss from fly ash (FA) dumping site in Badarpur thermal power plant (BTPP) New Delhi, India was studied. Three different experimental sites were selected at different distances from the thermal power plant. Ambient suspended particulate matter (SPM) and plant responses such as leaf pigments (chlorophyll a, chlorophyll b, and carotenoids), total chlorophyll, net photosynthetic rate, stomatal index (SI), stomatal conductance (SC), intercellular carbon dioxide concentration [CO2]i, net photosynthetic rate (NPR), nitrogen, nitrate, nitrate reductase activity, proline, protein, reducing sugar and sulphur content were measured. Considerable reduction in pigments (chlorophyll a, chlorophyll b and carotenoids), and total chlorophyll was observed at fly ash dumping site. Fly ash stress revealed the inhibitory effect on Nitrate reductase activity (NRA), Nitrate, soluble protein, and reducing sugar content, whereas stimulatory effect was found for the stomatal index, nitrogen, proline, antioxidants and sulphur content in the leaves. Under fly ash stress, stomatal conductance was low, leading to declining in photosynthetic rate and increase in the internal CO2 concentration of leaf. Single leaf area (SLA), leaf length and leaf width also showed a declining trend from control to the polluted site. Antioxidant enzymes increased in leaves reflecting stress and extenuation of reactive oxygen species (ROS). Copyright © 2016 Elsevier Inc. All rights reserved.

Application of LANDSAT to the surveillance of lake eutrophication in the Great Lakes basin. [Saginaw Bay, Michigan

NASA Technical Reports Server (NTRS)

Rogers, R. H.; Smith, V. E.; Scherz, J. P.; Woelkerling, W. J.; Adams, M. S.; Gannon, J. E. (Principal Investigator)

1977-01-01

The author has identified the following significant results. A step-by-step procedure for establishing and monitoring the trophic status of inland lakes with the use of LANDSAT data, surface sampling, laboratory analysis, and aerial observations were demonstrated. The biomass was related to chlorophyll-a concentrations, water clarity, and trophic state. A procedure was developed for using surface sampling, LANDSAT data, and linear regression equations to produce a color-coded image of large lakes showing the distribution and concentrations of water quality parameters, causing eutrophication as well as parameters which indicate its effects. Cover categories readily derived from LANDSAT were those for which loading rates were available and were known to have major effects on the quality and quantity of runoff and lake eutrophication. Urban, barren land, cropland, grassland, forest, wetlands, and water were included.

Defining Chlorophyll-a Reference Conditions in European Lakes

PubMed Central

Alves, Maria Helena; Argillier, Christine; van den Berg, Marcel; Buzzi, Fabio; Hoehn, Eberhard; de Hoyos, Caridad; Karottki, Ivan; Laplace-Treyture, Christophe; Solheim, Anne Lyche; Ortiz-Casas, José; Ott, Ingmar; Phillips, Geoff; Pilke, Ansa; Pádua, João; Remec-Rekar, Spela; Riedmüller, Ursula; Schaumburg, Jochen; Serrano, Maria Luisa; Soszka, Hanna; Tierney, Deirdre; Urbanič, Gorazd; Wolfram, Georg

2010-01-01

The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets. PMID:20401659

Laboratory tank studies of a single species of phytoplankton using a remote sensing fluorosensor

NASA Technical Reports Server (NTRS)

Brown, C. A., Jr.; Jarrett, O., Jr.; Farmer, F. H.

1981-01-01

Phytoplankton were grown in the laboratory for the purpose of testing a remote fluorosensor. The fluorosensor uses a unique four-wavelength dye laser system to excite phytoplankton bearing chlorophyll and to measure the chlorophyll fluorescence generated by this excitation. Six different species were tested, one at a time, and each was grown two to four times. Fluorescence measured by the fluorosensor provides good quantitative measurement of chlorophyll concentrations for all species tested while the cultures were in log phase growth. Fluorescene cross section ratios obtained in the single species tank tests support the hypothesis that the shape of the fluorescence cross section curve remains constant with the species (differences in fluorescence cross section ratios are a basis for determining composition of phytoplankton according to color group when a multiwavelength source of excitation is used. Linear relationships exist between extracted chlorophyll concentration and fluorescence measured by the remote fluorosensor during the log phase growth of phytoplankton cultures tested.

Reducing variability that is due to secondary pigments in the retrieval of chlorophyll a concentration from marine reflectance: a case study in the western equatorial Pacific Ocean.

PubMed

Gross, Lydwine; Frouin, Robert; Dupouy, Cécile; André, Jean Michel; Thiria, Sylvie

2004-07-10

A neural network is developed to retrieve chlorophyll a concentration from marine reflectance by use of the five visible spectral bands of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The network, dedicated to the western equatorial Pacific Ocean, is calibrated with synthetic data that vary in terms of atmospheric content, solar zenith angle, and secondary pigments. Pigment variability is based on in situ data collected in the study region and is introduced through nonlinear modeling of phytoplankton absorption as a function of chlorophyll a, b, and c and photosynthetic and photoprotectant carotenoids. Tests performed on simulated yet realistic data show that chlorophyll a retrievals are substantially improved by use of the neural network instead of classical algorithms, which are sensitive to spectrally uncorrelated effects. The methodology is general, i.e., is applicable to regions other than the western equatorial Pacific Ocean.

Optical Measurements and Modeling to Estimate Concentrations and Fluxes of Organic Matter in the Southern Ocean

NASA Technical Reports Server (NTRS)

Stramski, Dariusz; Mitchell, B. Greg; Marra, John W. (Technical Monitor)

2001-01-01

This project was a collaboration between two Principal Investigators, Dr. Dariusz Stramski and Dr. Greg Mitchell of Scripps Institution of Oceanography, University of California San Diego. Our overall goal was to conduct optical measurements and modeling to estimate concentrations of organic matter in the Southern Ocean in support of the U.S. JGOFS Process Study in this region. Key variables and processes of high relevance to accomplish the JGOFS goals include time and space resolution of phytoplankton pigments, particulate organic carbon, and the formation and export of organic carbon. Our project focused on establishing the fundamental relationships for parameterization of these variables and processes in terms of the optical properties of seawater, and developing understanding of why the Southern Ocean differs from other low-latitude systems, or has differentiation within. Our approach builds upon historical observations that optical properties provide a useful proxy for key reservoirs of organic matter such as chlorophyll alpha (Chl) and particulate organic carbon (POC) concentrations, which are of relevance to the JGOFS objectives. We carried out detailed studies of in situ and water sample optical properties including spectral reflectance, absorption, beam attenuation, scattering, and backscattering coefficients. We evaluated the ability to estimate Chl from the spectral reflectance (ocean color) in the Southern Ocean. We examined relationships between the ocean optical properties and particulate organic carbon. We developed, for the first time, an algorithm for estimating particulate organic carbon concentration in the surface ocean from satellite imagery of ocean color. With this algorithm, we obtained maps of POC distribution in the Southern Ocean showing the seasonal progression of POC in the austral spring-summer season. We also developed a semianalytical reflectance model for the investigated polar waters based on our field measurements of absorption and backscattering coefficients and Chl-dependent parameterizations of these coefficients. With this model, libraries of expected reflectance spectra for various chlorophyll concentrations can be generated with high spectral resolution for specific oceanic regions. In addition, our semianalytical reflectance model provided insight into the mechanisms which drive the empirical relationships between the ocean color and chlorophyll concentration. Our optical approach to the study of pigment and carbon concentrations will be directly relevant to development of system models and long-term monitoring of the Southern Ocean.

Response of desert biological soil crusts to alterations in precipitation frequency

USGS Publications Warehouse

Belnap, J.; Phillips, S.L.; Miller, M.E.

2004-01-01

Biological soil crusts, a community of cyanobacteria, lichens, and mosses that live on the soil surface, occur in deserts throughout the world. They are a critical component of desert ecosystems, as they are important contributors to soil fertility and stability. Future climate scenarios predict alteration of the timing and amount of precipitation in desert environments. Because biological soil crust organisms are only metabolically active when wet, and as soil surfaces dry quickly in deserts during late spring, summer, and early fall, the amount and timing of precipitation is likely to have significant impacts on the physiological functioning of these communities. Using the three dominant soil crust types found in the western United States, we applied three levels of precipitation frequency (50% below-average, average, and 50% above-average) while maintaining average precipitation amount (therefore changing both timing and size of applied events). We measured the impact of these treatments on photosynthetic performance (as indicated by dark-adapted quantum yield and chlorophyll a concentrations), nitrogenase activity, and the ability of these organisms to maintain concentrations of radiation-protective pigments (scytonemin, beta-carotene, echinenone, xanthophylls, and canthaxanthin). Increased precipitation frequency produced little response after 2.5 months exposure during spring (1 April-15 June) or summer (15 June-31 August). In contrast, most of the above variables had a large, negative response after exposure to increased precipitation frequency for 6 months spring-fall (1 April-31 October) treatment. The crusts dominated by the soil lichen Collema, being dark and protruding above the surface, dried the most rapidly, followed by the dark surface cyanobacterial crusts (Nostoc-Scytonema-Microcoleus), and then by the light cyanobacterial crusts (Microcoleus). This order reflected the magnitude of the observed response: crusts dominated by the lichen Collema showed the largest decline in quantum yield, chlorophyll a, and protective pigments; crusts dominated by Nostoc-Scytonema-Microcoleus showed an intermediate decline in these variables; and the crusts dominated by Microcoleus showed the least negative response. Most previous studies of crust response to radiation stress have been short-term laboratory studies, where organisms were watered and kept under moderate temperatures. Such conditions would give crust organisms access to ample carbon to respond to imposed stresses (e.g., production of UV-protective pigments, replacement of degraded chlorophyll). In contrast, our longer-term study showed that under field conditions of high air temperatures and frequent, small precipitation events, crust organisms appear unable to produce protective pigments in response to radiation stress, as they likely dried more quickly than when they received larger, less frequent events. Reduced activity time likely resulted in less carbon available to produce or repair chlorophyll a and/or protective pigments. Our findings may partially explain the global observation that soil lichen cover and richness declines as the frequency of summer rainfall increases. ?? Springer-Verlag 2003.

Seasonal variations of leaf and canopy properties tracked by ground-based NDVI imagery in a temperate forest.

PubMed

Yang, Hualei; Yang, Xi; Heskel, Mary; Sun, Shucun; Tang, Jianwu

2017-04-28

Changes in plant phenology affect the carbon flux of terrestrial forest ecosystems due to the link between the growing season length and vegetation productivity. Digital camera imagery, which can be acquired frequently, has been used to monitor seasonal and annual changes in forest canopy phenology and track critical phenological events. However, quantitative assessment of the structural and biochemical controls of the phenological patterns in camera images has rarely been done. In this study, we used an NDVI (Normalized Difference Vegetation Index) camera to monitor daily variations of vegetation reflectance at visible and near-infrared (NIR) bands with high spatial and temporal resolutions, and found that the infrared camera based NDVI (camera-NDVI) agreed well with the leaf expansion process that was measured by independent manual observations at Harvard Forest, Massachusetts, USA. We also measured the seasonality of canopy structural (leaf area index, LAI) and biochemical properties (leaf chlorophyll and nitrogen content). We found significant linear relationships between camera-NDVI and leaf chlorophyll concentration, and between camera-NDVI and leaf nitrogen content, though weaker relationships between camera-NDVI and LAI. Therefore, we recommend ground-based camera-NDVI as a powerful tool for long-term, near surface observations to monitor canopy development and to estimate leaf chlorophyll, nitrogen status, and LAI.

Relationships between pigment composition variation and reflectance for plant species from a coastal savannah in California

NASA Technical Reports Server (NTRS)

Ustin, Susan L.; Sanderson, Eric W.; Grossman, Yaffa; Hart, Quinn J.

1993-01-01

Advances in imaging spectroscopy have indicated that remotely sensed reflectance measurements of the plant canopy may be used to identify and qualify some classes of canopy biochemicals; however, the manner in which differences in biochemical compositions translate into differences is not well understood. Most frequently, multiple linear regression routines have been used to correlate narrow band reflectance values with measured biochemical concentrations. Although some success has been achieved with such methods for given data sets, the bands selected by multiple regression are not consistent between data sets, nor is it always clear what physical or biological basis underlies the correlation. To examine the relationship between biochemical concentration and leaf reflectance signal we chose to focus on the visible spectrum where the primary biochemical absorbances are due to photosynthetic pigments. Pigments provide a range of absorbance features, occur over a range of concentrations in natural samples, and are ecophysiologically important. Concentrations of chlorophyll, for example, have been strongly correlated to foliar nitrogen levels within a species and to photosynthetic capacity across many species. In addition pigments effectively absorb most of the photosynthetically active radiation between 400-700 nm, a spectral region for which silicon detectors have good signal/noise characteristics. Our strategy has been to sample a variety of naturally occurring species to measure leaf reflectance and pigment compositions. We hope to extend our understanding of pigment reflectance effects to interpret small overlapping absorbances of other biochemicals in the infrared region. For this reason, selected samples were also tested to determine total nitrogen, crude protein, cellulose, and lignin levels. Leaf reflectance spectra measured with AVIRIS bandwidths and wavelengths were compared between species and within species and for differences between seasons, for changes in the the shape of the spectra. We attempt to statistically correlate these shape changes with differences in pigment compositions. In parallel with our comparisons of pigment composition and leaf reflectance, we have modified the PROSPECT leaf reflectance model to test the contributions of pigments or pigment group concentrations. PROSPECT considers a leaf as a multi-layer dielectric plane with an uneven surface. Jacquemoud adapted the basic analysis of Allen for surface effects, a leaf thickness factor, and the absorption of water and chlorophyll (actually all pigments) and the plant matrix. Our modifications to PROSPECT in the forward direction include breaking out the pigment concentration parameter into separate components for chlorophyll a and b and a number of xanthophylls and carotenes, and introducing a shift and convolution function to model the spread and shift from their in vitro measurements to their in vivo state. Further, we have considered how the matrix elements (i.e., all biochemicals and structural effects not modeled explicity) vary with species.

Impact of ocean acidification on Arctic phytoplankton blooms and dimethyl sulfide concentration under simulated ice-free and under-ice conditions

NASA Astrophysics Data System (ADS)

Hussherr, Rachel; Levasseur, Maurice; Lizotte, Martine; Tremblay, Jean-Éric; Mol, Jacoba; Thomas, Helmuth; Gosselin, Michel; Starr, Michel; Miller, Lisa A.; Jarniková, Tereza; Schuback, Nina; Mucci, Alfonso

2017-05-01

In an experimental assessment of the potential impact of Arctic Ocean acidification on seasonal phytoplankton blooms and associated dimethyl sulfide (DMS) dynamics, we incubated water from Baffin Bay under conditions representing an acidified Arctic Ocean. Using two light regimes simulating under-ice or subsurface chlorophyll maxima (low light; low PAR and no UVB) and ice-free (high light; high PAR + UVA + UVB) conditions, water collected at 38 m was exposed over 9 days to 6 levels of decreasing pH from 8.1 to 7.2. A phytoplankton bloom dominated by the centric diatoms Chaetoceros spp. reaching up to 7.5 µg chlorophyll a L-1 took place in all experimental bags. Total dimethylsulfoniopropionate (DMSPT) and DMS concentrations reached 155 and 19 nmol L-1, respectively. The sharp increase in DMSPT and DMS concentrations coincided with the exhaustion of NO3- in most microcosms, suggesting that nutrient stress stimulated DMS(P) synthesis by the diatom community. Under both light regimes, chlorophyll a and DMS concentrations decreased linearly with increasing proton concentration at all pH levels tested. Concentrations of DMSPT also decreased but only under high light and over a smaller pH range (from 8.1 to 7.6). In contrast to nano-phytoplankton (2-20 µm), pico-phytoplankton ( ≤ 2 µm) was stimulated by the decreasing pH. We furthermore observed no significant difference between the two light regimes tested in term of chlorophyll a, phytoplankton abundance and taxonomy, and DMSP and DMS net concentrations. These results show that ocean acidification could significantly decrease the algal biomass and inhibit DMS production during the seasonal phytoplankton bloom in the Arctic, with possible consequences for the regional climate.

Analysis of high altitude remotely sensed data collected in the Nantucket Shoals experiment 4-15 May, 1981

NASA Technical Reports Server (NTRS)

Ohlhorst, C. W.

1982-01-01

High altitude ocean color scanner ratios of band 2 (456 to 476 nanometers) to band 4 (539 to 559 nanometers) and band 1 (418 to 438 nanometers) to band 3 (498 to 518 nanometers) had high correlation coefficient values (-0.928 and 0.891 respectively) with seven boat sampled chlorophyll a measurements. The range of chlorophyll a concentrations was small (1.7-2.58 mg/cu m.). Each ratio was used to calculate chlorophyll a values for the center pixel of each scan line on flight lines 5 and 6. The two ratios produced dissimilar chlorophyll a trends. Due to the high noise level in the scanner data, no reliable synoptic chlorophyll a map could be generated with either ratio algorithm.

Effect of discharge on the chlorophyll a distribution in the tidally-influenced Potomac River

USGS Publications Warehouse

Bennett, J.P.; Woodward, J.W.; Shultz, D.J.

1986-01-01

In the tidal Potomac River, high river discharges during the spring are associated with high chlorophyll a concentrations in the following in the following summer, assuming that summertime light and temperature conditions are favorable. Spring floods deliver large loads of particulate N and P to the tidal river. This particulate N and P could be mineralized by bacteria to inorganic N and P and released to the water column where it is available for phytoplankton use during summertime. However, during the study period relatively low concentrations of chlorophyll a (less than 50 ??g l-1 occurred in the tidal river if average monthly discharge during July or August exceeded 200 m3s-1. Discharge and other conditions combined to produce conditions favorable for nuisance levels of chlorophyll a (greater than 100 ??g l-1 approximately one year out of four. Chlorophyll a maxima occurred in the Potomac River transition zone and estuary during late winter (dinoflagellates) and spring (diatoms). Typical seasonal peak concentrations were achieved at discharges as high as 970 m3 s-1, but sustained discharges greater than 1,100 m3 s-1 retarded development. Optimum growth conditions occurred following runoff events of 10 to 15 d duration which produced transit times to the transition zone of 7 to 10 d. Wet years with numerous moderate-sized runoff events, such as 1980, tend to produce greater biomass in the transition zone and estuary than do dry years such as 1981. ?? 1986 Estuarine Research Federation.

Optical and Ancillary Measurements at High Latitudes in Support of the MODIS Ocean Validation Program

NASA Technical Reports Server (NTRS)

Stramski, Dariusz; Stramska, Malgorzata; Starr, David OC. (Technical Monitor)

2002-01-01

The overall goal of this project was to validate and refine ocean color algorithms at high latitudes in the north polar region of the Atlantic. The specific objectives were defined as follows: (1) to identify and quantify errors in the satellite-derived water-leaving radiances and chlorophyll concentration; (2) to develop understanding of these errors; and (3) to improve in-water ocean color algorithms for retrieving chlorophyll concentration in the investigated region.

Phytoplankton in the Beaufort and Chukchi Seas: Distributions, Dynamics and Environmental Forcing

NASA Technical Reports Server (NTRS)

Wang, Jian; Cota, Glenn F.; Comiso, Josefino C.

2005-01-01

Time-series of remotely sensed distributions of phytoplankton, sea ice, surface temperature, albedo, and clouds were examined to evaluate the impact of the variability of environmental conditions and physical forcing on the phytoplankton distribution in the Beaufort and Chukchi Seas. Large-scale distributions of these parameters were studied for the first time using weekly and monthly composites from April 1998 through September 2002. The basic data set used in this study are phytoplankton pigment concentration derived from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), ice concentration obtained from the Special Sensor Microwave Imager (SSM/I) and surface temperature, cloud cover, and albedo derived from the Advanced Very High Resolution Radiometer (AVHRR). Seasonal variations of the sea ice cover was observed to be the dominant environmental factor as the ice edge blooms followed the retreating marginal ice zones northward. Blooms were most prominent in the southwestern Chukchi Sea, and were especially persistent immediately north of the Bering Strait in nutrient- rich Anadyr water and in some fronts. Chlorophyll concentrations are shown to increase from a nominal value during onset of melt in April to a maximum value in mid-spring or summer depending on location. Large interannual variability of ice cover and phytoplankton distributions was observed with the year 1998 being uniquely associated with an early season occurrence of a massive bloom. This is postulated to be caused in part by a rapid response of phytoplankton to an early retreat of the sea ice cover in the Beaufort Sea region. Correlation analyses showed relatively high negative correlation between chlorophyll and ice concentration with the correlation being highest in May, the correlation coefficient being -0.45. 1998 was also the warmest among the five years globally and the sea ice cover was least extensive in the Beaufort-Khukchi Sea region, partly because of the 1997-98 El Nino. Strong correlations were noted between ice extent and surface temperature, the correlation coefficient being highest at - 0.79 in April, during the onset of the bloom period

Manipulation of Origin of Life Molecules: Recognizing Single-Molecule Conformations in β-Carotene and Chlorophyll-a/β-Carotene Clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngo, Anh T.; Skeini, Timur; Iancu, Violeta

Carotenoids and chlorophyll are essential parts of plant leaves and are involved in photosynthesis, a vital biological process responsible for the origin of life on Earth. Here, we investigate how beta-carotene and chlorophyll-a form mixed molecular phases On a Au(111) surface using low-temperature scanning tunneling microscopy and molecular manipulation at the single-molecule level supported by density functional theory calculations. By isolating individual molecules from nanoscale molecular clusters with a scanning tunneling microscope tip, we are able to identify five beta-carotene conformations including a structure exhibiting a three-dimensional conformation. Furthermore, molecular resolution images enable direct visualization of beta-carotene/chlorophyll-a clsuters, with intimatemore » structural details highlighting how they pair: beta-carotene preferentially positions next to chlorophyll-a and induces switching of chlorophyll-a from straight to several bent tail conformations in the molecular clusters.« less

An Empirical Approach to Ocean Color Data: Reducing Bias and the Need for Post-Launch Radiometric Re-Calibration

NASA Technical Reports Server (NTRS)

Gregg, Watson W.; Casey, Nancy W.; O'Reilly, John E.; Esaias, Wayne E.

2009-01-01

A new empirical approach is developed for ocean color remote sensing. Called the Empirical Satellite Radiance-In situ Data (ESRID) algorithm, the approach uses relationships between satellite water-leaving radiances and in situ data after full processing, i.e., at Level-3, to improve estimates of surface variables while relaxing requirements on post-launch radiometric re-calibration. The approach is evaluated using SeaWiFS chlorophyll, which is the longest time series of the most widely used ocean color geophysical product. The results suggest that ESRID 1) drastically reduces the bias of ocean chlorophyll, most impressively in coastal regions, 2) modestly improves the uncertainty, and 3) reduces the sensitivity of global annual median chlorophyll to changes in radiometric re-calibration. Simulated calibration errors of 1% or less produce small changes in global median chlorophyll (less than 2.7%). In contrast, the standard NASA algorithm set is highly sensitive to radiometric calibration: similar 1% calibration errors produce changes in global median chlorophyll up to nearly 25%. We show that 0.1% radiometric calibration error (about 1% in water-leaving radiance) is needed to prevent radiometric calibration errors from changing global annual median chlorophyll more than the maximum interannual variability observed in the SeaWiFS 9-year record (+/- 3%), using the standard method. This is much more stringent than the goal for SeaWiFS of 5% uncertainty for water leaving radiance. The results suggest ocean color programs might consider less emphasis of expensive efforts to improve post-launch radiometric re-calibration in favor of increased efforts to characterize in situ observations of ocean surface geophysical products. Although the results here are focused on chlorophyll, in principle the approach described by ESRID can be applied to any surface variable potentially observable by visible remote sensing.

Large Scale Variability of Phytoplankton Blooms in the Arctic and Peripheral Seas: Relationships with Sea Ice, Temperature, Clouds, and Wind

NASA Technical Reports Server (NTRS)

Comiso, Josefino C.; Cota, Glenn F.

2004-01-01

Spatially detailed satellite data of mean color, sea ice concentration, surface temperature, clouds, and wind have been analyzed to quantify and study the large scale regional and temporal variability of phytoplankton blooms in the Arctic and peripheral seas from 1998 to 2002. In the Arctic basin, phytoplankton chlorophyll displays a large symmetry with the Eastern Arctic having about fivefold higher concentrations than those of the Western Arctic. Large monthly and yearly variability is also observed in the peripheral seas with the largest blooms occurring in the Bering Sea, Sea of Okhotsk, and the Barents Sea during spring. There is large interannual and seasonal variability in biomass with average chlorophyll concentrations in 2002 and 2001 being higher than earlier years in spring and summer. The seasonality in the latitudinal distribution of blooms is also very different such that the North Atlantic is usually most expansive in spring while the North Pacific is more extensive in autumn. Environmental factors that influence phytoplankton growth were examined, and results show relatively high negative correlation with sea ice retreat and strong positive correlation with temperature in early spring. Plankton growth, as indicated by biomass accumulation, in the Arctic and subarctic increases up to a threshold surface temperature of about 276-277 degree K (3-4 degree C) beyond which the concentrations start to decrease suggesting an optimal temperature or nutrient depletion. The correlation with clouds is significant in some areas but negligible in other areas, while the correlations with wind speed and its components are generally weak. The effects of clouds and winds are less predictable with weekly climatologies because of unknown effects of averaging variable and intermittent physical forcing (e.g. over storm event scales with mixing and upwelling of nutrients) and the time scales of acclimation by the phytoplankton.

Upwelling Dynamic Based on Satellite and INDESO Data in the Flores Sea

NASA Astrophysics Data System (ADS)

Kurniawan, Reski; Suriamihardja, D. A.; Hamzah Assegaf, Alimuddin

2018-03-01

Upwelling phenomenon is crucial to be forecasted, mainly concerning the information of potential fishery areas. Utilization of calibrated model for recorded upwelling such as INDESO gives benefit for historical result up to the present time. The aim of this study is to estimate areas and seasons of upwelling occurrences in the Flores Sea using data assimilation of satellite and modeling result. This study uses sea surface temperature, chlorophyll-a data from level 3 of MODIS image and sea surface height from satellite Jason-2 monthly for three years (2014-2016) and INDESO model data for sea surface temperature, sea surface height, and chlorophyll-a daily for three years (2014-2016). The upwelling is indicated by declining of sea surface temperature, sea surface height and increasing of chlorophyll-a. Verification is conducted by comparing the model result with recorded MODIS satellite image. The result shows that the area of southern Makassar Strait having occurrences of upwelling phenomenon every year starting in June, extended to July and August. The strongest upwelling occurred in 2015 covering more or less the area of 23,000 km2. The relation of monthly data of satellite has significantly correlated with daily data of INDESO model

Laser induced fluoroescence from algae: Results of a ship-borne field test

NASA Technical Reports Server (NTRS)

Hartmann, B.; Steinvall, O.; Widen, A.

1981-01-01

A basis is provided for the feasibility of air-borne laser fluorosensing not only of chlorophyll but also of pollutants such as oils and chemicals. There was a satisfactory correlation between the laser data and those obtained manually. The absolute determination of the chlorophyll concentration is discussed.

High Spectral Resolution MODIS Algorithms for Ocean Chlorophyll in Case II Waters

NASA Technical Reports Server (NTRS)

Carder, Kendall L.

2004-01-01

The Case 2 chlorophyll a algorithm is based on a semi-analytical, bio-optical model of remote sensing reflectance, R(sub rs)(lambda), where R(sub rs)(lambda) is defined as the water-leaving radiance, L(sub w)(lambda), divided by the downwelling irradiance just above the sea surface, E(sub d)(lambda,0(+)). The R(sub rs)(lambda) model (Section 3) has two free variables, the absorption coefficient due to phytoplankton at 675 nm, a(sub phi)(675), and the absorption coefficient due to colored dissolved organic matter (CDOM) or gelbstoff at 400 nm, a(sub g)(400). The R(rs) model has several parameters that are fixed or can be specified based on the region and season of the MODIS scene. These control the spectral shapes of the optical constituents of the model. R(sub rs)(lambda(sub i)) values from the MODIS data processing system are placed into the model, the model is inverted, and a(sub phi)(675), a(sub g)(400) (MOD24), and chlorophyll a (MOD21, Chlor_a_3) are computed. Algorithm development is initially focused on tropical, subtropical, and summer temperate environments, and the model is parameterized in Section 4 for three different bio-optical domains: (1) high ratios of photoprotective pigments to chlorophyll and low self-shading, which for brevity, we designate as 'unpackaged'; (2) low ratios and high self-shading, which we designate as 'packaged'; and (3) a transitional or global-average type. These domains can be identified from space by comparing sea-surface temperature to nitrogen-depletion temperatures for each domain (Section 5). Algorithm errors of more than 45% are reduced to errors of less than 30% with this approach, with the greatest effect occurring at the eastern and polar boundaries of the basins. Section 6 provides an expansion of bio-optical domains into high-latitude waters. The 'fully packaged' pigment domain is introduced in this section along with a revised strategy for implementing these variable packaging domains. Chlor_a_3 values derived semi-analytically and Chlor_a_2 values derived empirically using the O Reilly et al. OC3M algorithm from MODIS Terra radiances are compared to field chlorophyll-a concentrations in Sections 7 and 8.

Manganese toxicity to chlorophyll synthesis in tobacco callus. [Nicotiana tabacum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clairmont, K.B.; Hagar, W.G.; Davis, E.A.

1986-01-01

Tobacco (Nicotiana tabacum) pith explants were grown on manganese containing medium. At moderate concentration (10 millimolar), manganese selectivity inhibited chlorophyll synthesis, resulting initially in growth of white callus. Several weeks later the white callus turned brown due to the accumulation of a pigment identified as protoporphyrin IX by its elution profile using high performance liquid chromatography, by its absorption spectrum, and by its fluorescence properties. At a concentration of 100 millimolar manganese the pigment accumulated without growth of the explant.

Seasonal Phytoplankton Dynamics in the Eastern Tropical Atlantic

NASA Technical Reports Server (NTRS)

Monger, Bruce; McClain, Charles; Murtugudde, Ragu

1997-01-01

The coastal zone color scanner (CZCS) that operated aboard the Nimbus 7 satellite provided extensive coverage of phytoplankton pigment concentrations in the surface waters of the eastern tropical Atlantic (ETA) from March 1979 to February 1980 and coincided with four major research cruises to this region. Total primary production within the ETA (5 deg N-10 deg S, 25 deg W-10 deg E) was determined from CZCS pigment estimates and an empirical algorithm derived from concurrent in situ data taken along 4 deg W that relates near-surface chlorophyll concentration and integrated primary production. We estimated an average annual production for the ETA of 2.3 Gt C/yr with an associated 3.5-fold seasonal variation in the magnitude of this production. We describe the principal physical mechanisms controlling seasonal phytoplankton dynamics within the ETA and propose that in addition to seasonal change in the thermocline depth, one must also consider changes in the depth of the equatorial under current. An extensive validation effort indicates that the standard CZCS global products are a conservative estimate of pigment concentrations in ETA surface waters. Significant underestimates by the CZCS global products were observed in June and July which we attributed, in part, to aerosol correction errors and, more importantly, to errors caused by a significant reduction in the concentration of near-surface dissolved organic matter that resulted from strong equatorial upwelling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hershkovitz, N.; Oren, A.; Cohen, Y.

The drought-resistant cyanobacteria Phormidium autumnale, strain LPP{sub 4}, and a Chroococcidiopsis sp. accumulated trehalose, sucrose, and both trehalose and sucrose, respectively, in response to matric water stress. Accumulated sugar concentrations reached values of up to 6.2 {mu}g of trehalose per {mu}g of chlorophyll in P. autumnale, 6.9 {mu}g of sucrose per {mu}g of chlorophyll in LPP{sub 4}, and 4.1 {mu}g of sucrose and 3.2 {mu}g of trehalose per {mu}g of chlorophyll in the Chroococcidiopsis sp. The same sugars were accumulated by these cyanobacteria in similar concentrations under osmotic water stress. Cyanobacteria that did not show drought resistance (Plectonema boryanum andmore » Synechococcus strain PCC 7942) did not accumulate significant amounts of sugars when matric water stress was applied.« less

Phytoplankton transport to coral reefs by internal solitons in the northern South China Sea

NASA Astrophysics Data System (ADS)

Wang, Yu-Huai

2016-09-01

Evidence is presented that waters containing high concentrations of chlorophyll are transported by internal waves to the fore-reef slope of Dongsha Atoll in the northern South China Sea. High vertical resolution mooring measurements of temperature, pressure, and chlorophyll fluorescence revealed that the internal soliton cores could transport chlorophyll vertically downward and increase concentrations by an order of magnitude near the seafloor, compared to background levels. The reef areas that are potentially nourished by the pulses of phytoplankton are dominated by alcyonacean soft corals, while other reef areas that are less or not at all affected by internal waves are dominated by scleractinian hard corals. This suggests that the delivery of phytoplankton by internal solitons provides a plentiful food source that benefits the growth of soft corals.

Changes in chlorophyll and polyphenols content in Camellia sinensis var. sinensis at different stage of leaf maturity

NASA Astrophysics Data System (ADS)

Prawira-Atmaja, M. I.; Shabri; Khomaini, H. S.; Maulana, H.; Harianto, S.; Rohdiana, D.

2018-03-01

Chlorophyll and polyphenols are chemical compound related to parameter quality of green tea. We studied the variation of chlorophyll and polyphenol in the development stage of tea leaves (bud, 1st, 2nd, 3rd, and 4th). Five clones of tea (Camelia sinensis var. sinensis) from Indonesia and a clone from Japan were used in this study. The results showed that total chlorophyll and total polyphenol content in bud between 1.59-2.15 mg/g (db) and 12.24-14.59% respectively. The concentration of chlorophyll increased significantly with developments stage of leaf while total polyphenol tended to decrease with leaf maturity. Pearson Correlation analysis showed that chlorophyll content was negatively correlated (r = -0.83; p = 0.05) with total polyphenol during developmental stage of tea leaves. Results suggests that five clones of tea from Indonesia have similar quality with tea clone from Japan in chlorophyll and polyphenol content. The present study also provides guidelines on application plucking standard to produce high quality of green tea.

Spatial and temporal variability of chlorophyll and primary productivity in surface waters of southern Chile (41.5 43° S)

NASA Astrophysics Data System (ADS)

Iriarte, J. L.; González, H. E.; Liu, K. K.; Rivas, C.; Valenzuela, C.

2007-09-01

The southern fjord region of Chile is a unique ecosystem characterized by complex marine-terrestrial-atmospheric interactions that result in high biological production. Since organic nitrogen from terrestrial and atmospheric compartments is highly significant in this region (>40%), as is the low NO 3:PO 4 ratio in surface waters, it is suggested that fertilization from inorganic and organic nitrogen sources has a strong influence on both phytoplankton biomass/primary production and harmful algae bloom dynamics. The data presented in this paper provide an opportunity to improve our knowledge of phytoplankton dynamics on temporal and spatial mesoscales. Ocean color data from NASA (SeaWiFS) for chlorophyll and primary production estimates and in situ surface measurement of inorganic nutrients, phytoplankton biomass, and primary productivity revealed that the coastal waters of southern Chile have a classical spring and autumn chlorophyll bloom cycle in which primary production is co-limited by strong seasonal changes in light and nitrate. During spring blooms, autotrophic biomass (such as chlorophyll a, Chl- a) and primary production estimates reached 25 mg Chl- a m -3 and 23 mg C m -3 h -1, respectively, and micro-phytoplankton accounted for a significant portion of the biomass (60%) in spring. The contribution of phytoplankton size classes to total chlorophyll a revealed the dominance of nanoplankton (>50%) in winter and post-bloom periods (<1.0 mg Chl- a m -3).

Defining the Habitat of Pacific Tuna of the Eastern Tropical Pacific from Satellite Imagery, Climatologies, and a Global Circulation Model

NASA Astrophysics Data System (ADS)

Kiefer, D. A.; Hinton, M. G.; Armstrong, E. M.; Harrison, D. P.; Menemenlis, D.; Hu, C.

2016-02-01

With support from NASA's Ecological Forecasting program, we have developed a Tuna Stock Assessment Support System, which merges time series of satellite imagery, a global ocean circulation model, climatology from field surveys, and fisheries data on catch and effort. The purpose of this software is to extract information on the habitat of skipjack, bigeye, and yellowfin tuna in the Eastern Tropical Pacific. The support system is based upon a 50-year record of catch and effort from long-line and purse seine vessels provide by the Inter-American Tropical Tuna Commission. This database, which covers thousands of kilometers of ocean surface, provides monthly information at a 1 degree spatial resolution for the purse seine fleet and 5 degree resolution for the long line fishery. This data is then merged in time and space with satellite imagery of sea surface temperature, chlorophyll, and height, as well as NODC climatologies of oxygen concentration and temperature, and output from NASA's ECCO-2 global circulation model, which provides 3-dimensional simulations of water density, current velocity, mixed layer depth, and sea surface height. Our analyses have yielded a broad range of understanding of the habitat and dynamics both the fish and the fisherman. The purse seine ground, which targets younger tuna, is constrained to waters where the hypoxic layer is shallow. The longline fishery, which targets older tuna, is not constrained by the hypoxic layer and has a much larger distribution. We have characterized the preferences of each species to environmental variables including the depth of the hypoxic layer, the depth of the water column, as well as sea surface height, temperature, and chlorophyll concentration. Finally, the analyses have revealed information on local depletion by fishing, the size distribution of the schools of younger fish, and the impact of ENSO on fishing activities.

Deciphering the Temporal and Spatial Complexity in Submarine Canyons in Antarctica: the Role of Mixed Layer Depth in Regulating Primary Production

NASA Astrophysics Data System (ADS)

Carvalho, F.; Kohut, J. T.; Schofield, O.; Oliver, M. J.; Gorbunov, M. Y.

2016-02-01

There is a high spatial and temporal variability in the biophysical processes regulating primary productivity in submarine canyons in the West Antarctic Peninsula (WAP). WAP canyon heads are considered biological "hotspots" by providing predictable food resource and driving penguin foraging locations. Because the physiology and composition of the phytoplankton blooms and the physical mechanisms driving them aren't well understood, we aim to characterize the dynamics of the spring phytoplankton bloom at the head of a canyon in the WAP. A 6-year record of Slocum glider deployments is analyzed, corresponding to over 16,000 water column profiles. The mixed layer depth (MLD), determined by the maximum of the buoyancy frequency criteria, was found to be the MLD definition with the highest ecological relevance. The same holds true for other regions in Antarctica such as the Ross and Amundsen Seas. A FIRe sensor on a glider was used to evaluate physiological responses of phytoplankton to canyon dynamics using fluorescence kinetics. Initial results show a spatial influence, with increased photosynthetic efficiencies found at the canyon head. The strongest signal was the seasonal cycle. The shoaling of the MLD in early January results in increased chlorophyll a concentrations and as MLD deepens in mid season due to wind forcing, phytoplankton concentrations decrease, likely due to decreased light availability. A consistent secondary peak in chlorophyll matches a shoaling in MLD later in the growth season. A steady warming and increase in salinity of the MLD is seen throughout the season. Spatial differences were recorded at the head of the canyon and result from the local circulation. Shallower MLD found on the northern region are consistent with a fresher surface ocean (coastal influence) and increased chlorophyll concentrations. The southern region is thought to be more oceanic influenced as intrusions of warm deep water (mUCDW) to the upper water column were recorded regularly there.

Potential Climate Change Effects on the Habitat of Antarctic Krill in the Weddell Quadrant of the Southern Ocean

PubMed Central

Hill, Simeon L.; Phillips, Tony; Atkinson, Angus

2013-01-01

Antarctic krill is a cold water species, an increasingly important fishery resource and a major prey item for many fish, birds and mammals in the Southern Ocean. The fishery and the summer foraging sites of many of these predators are concentrated between 0° and 90°W. Parts of this quadrant have experienced recent localised sea surface warming of up to 0.2°C per decade, and projections suggest that further widespread warming of 0.27° to 1.08°C will occur by the late 21st century. We assessed the potential influence of this projected warming on Antarctic krill habitat with a statistical model that links growth to temperature and chlorophyll concentration. The results divide the quadrant into two zones: a band around the Antarctic Circumpolar Current in which habitat quality is particularly vulnerable to warming, and a southern area which is relatively insensitive. Our analysis suggests that the direct effects of warming could reduce the area of growth habitat by up to 20%. The reduction in growth habitat within the range of predators, such as Antarctic fur seals, that forage from breeding sites on South Georgia could be up to 55%, and the habitat’s ability to support Antarctic krill biomass production within this range could be reduced by up to 68%. Sensitivity analysis suggests that the effects of a 50% change in summer chlorophyll concentration could be more significant than the direct effects of warming. A reduction in primary production could lead to further habitat degradation but, even if chlorophyll increased by 50%, projected warming would still cause some degradation of the habitat accessible to predators. While there is considerable uncertainty in these projections, they suggest that future climate change could have a significant negative effect on Antarctic krill growth habitat and, consequently, on Southern Ocean biodiversity and ecosystem services. PMID:23991072

Potential climate change effects on the habitat of antarctic krill in the weddell quadrant of the southern ocean.

PubMed

Hill, Simeon L; Phillips, Tony; Atkinson, Angus

2013-01-01

Antarctic krill is a cold water species, an increasingly important fishery resource and a major prey item for many fish, birds and mammals in the Southern Ocean. The fishery and the summer foraging sites of many of these predators are concentrated between 0° and 90°W. Parts of this quadrant have experienced recent localised sea surface warming of up to 0.2°C per decade, and projections suggest that further widespread warming of 0.27° to 1.08°C will occur by the late 21(st) century. We assessed the potential influence of this projected warming on Antarctic krill habitat with a statistical model that links growth to temperature and chlorophyll concentration. The results divide the quadrant into two zones: a band around the Antarctic Circumpolar Current in which habitat quality is particularly vulnerable to warming, and a southern area which is relatively insensitive. Our analysis suggests that the direct effects of warming could reduce the area of growth habitat by up to 20%. The reduction in growth habitat within the range of predators, such as Antarctic fur seals, that forage from breeding sites on South Georgia could be up to 55%, and the habitat's ability to support Antarctic krill biomass production within this range could be reduced by up to 68%. Sensitivity analysis suggests that the effects of a 50% change in summer chlorophyll concentration could be more significant than the direct effects of warming. A reduction in primary production could lead to further habitat degradation but, even if chlorophyll increased by 50%, projected warming would still cause some degradation of the habitat accessible to predators. While there is considerable uncertainty in these projections, they suggest that future climate change could have a significant negative effect on Antarctic krill growth habitat and, consequently, on Southern Ocean biodiversity and ecosystem services.

Effects of the exposure of TiO2 nanoparticles on basil (Ocimum basilicum) for two generations.

PubMed

Tan, Wenjuan; Du, Wenchao; Darrouzet-Nardi, Anthony J; Hernandez-Viezcas, Jose A; Ye, Yuqing; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

2018-09-15

There is a lack of information about the transgenerational effects of titanium dioxide nanoparticles (nano-TiO 2 ) in plants. This study aimed to evaluate the impacts of successive exposure of nano-TiO 2 with different surface properties to basil (Ocimum basilicum). Seeds from plants exposed or re-exposed to pristine, hydrophobic, or hydrophilic nano-TiO 2 were cultivated for 65 days in soil unamended or amended with 750 mg·kg -1 of the respective particles. Plant growth, concentration of titanium and essential elements, as well as content of carbohydrates and chlorophyll were evaluated. There were no differences on Ti concentration in roots of plants sequentially exposed to pristine or hydrophobic nano-TiO 2 , or in roots of plants exposed to the corresponding particle, only in the second cycle. However, sequential exposure to hydrophilic particles resulted in 65.2% less Ti in roots, compared to roots of plants exposed the same particles, only in the second cycle. The Ti concentrations in shoots were similar in all treatments. On the other hand, pristine and hydrophilic particles reduced Mg in root by 115% and 81%, respectively, while pristine and hydrophobic particles reduced Ni in shoot by 84% and 75%, respectively, compared to unexposed plants in both cycles. Sequential exposure to pristine nano-TiO 2 increased stomatal conductance (214%, p ≤ 0.10), compared to plants that were never exposed. Hydrophobic and hydrophilic nano-TiO 2 reduced chlorophyll b (52%) and total chlorophyll (30%) but increased total sugar (186%) and reducing sugar (145%), compared to unexposed plants in both cycles. Sequential exposure to hydrophobic or hydrophilic nano-TiO 2 resulted in more adverse effects on photosynthesis but in positive effects on plant growth, compared to pristine nano-TiO 2 . Copyright © 2018 Elsevier B.V. All rights reserved.

Negative response of photosynthesis to natural and projected high seawater temperatures estimated by pulse amplitude modulation fluorometry in a temperate coral

PubMed Central

Caroselli, Erik; Falini, Giuseppe; Goffredo, Stefano; Dubinsky, Zvy; Levy, Oren

2015-01-01

Balanophyllia europaea is a shallow water solitary zooxanthellate coral, endemic to the Mediterranean Sea. Extensive field studies across a latitudinal temperature gradient highlight detrimental effects of rising temperatures on its growth, demography, and skeletal characteristics, suggesting that depression of photosynthesis at high temperatures might cause these negative effects. Here we test this hypothesis by analyzing, by means of pulse amplitude modulation fluorometry, the photosynthetic efficiency of B. europaea specimens exposed in aquaria to the annual range of temperatures experienced in the field (13, 18, and 28°C), and two extreme temperatures expected for 2100 as a consequence of global warming (29 and 32°C). The indicators of photosynthetic performance analyzed (maximum and effective quantum yield) showed that maximum efficiency was reached at 20.0–21.6°C, slightly higher than the annual mean temperature in the field (18°C). Photosynthetic efficiency decreased from 20.0 to 13°C and even more strongly from 21.6 to 32°C. An unusual form of bleaching was observed, with a maximum zooxanthellae density at 18°C that strongly decreased from 18 to 32°C. Chlorophyll a concentration per zooxanthellae cell showed an opposite trend as it was minimal at 18°C and increased from 18 to 32°C. Since the areal chlorophyll concentration is the product of the zooxanthellae density and its cellular content, these trends resulted in a homogeneous chlorophyll concentration per coral surface across temperature treatments. This confirms that B. europaea photosynthesis is progressively depressed at temperatures >21.6°C, supporting previous hypotheses raised by the studies on growth and demography of this species. This study also confirms the threats posed to this species by the ongoing seawater warming. PMID:26582993

Limnological Conditions in Lake William C. Bowen and Municipal Reservoir #1, Spartanburg County, South Carolina, August to September 2005, May 2006, and October 2006

USGS Publications Warehouse

Journey, Celeste A.; Abrahamsen, Thomas A.

2008-01-01

The U.S. Geological Survey, in cooperation with the Spartanburg Water System, conducted three spatial surveys of the limnological conditions in Lake William C. Bowen (Lake Bowen) and Municipal Reservoir #1 (Reservoir #1), Spartanburg County, South Carolina, during August to September 2005, May 2006, and October 2006. The surveys were conducted to identify spatial distribution and concentrations of geosmin and 2-methylisoborneol, common trophic state indicators (nutrients, transparency, and chlorophyll a), algal community structure, and stratification of the water column at the time of sampling. Screening tools such as the Carlson trophic state index, total nitrogen to total phosphorus ratios, and relative thermal resistance to mixing were used to help compare data among sites and among seasons. Water-column samples were collected at two depths at each selected site: a near-surface sample collected above a 1-meter depth and a lake-bottom sample collected at a depth of 2.5 to 7 meters, depending on the depth at the site. The degree of stratification of the water column was demonstrated by temperature-depth profiles and computed relative thermal resistance to mixing. Seasonal occurrence of thermal stratification (August to September 2005; May 2006) and de-stratification (October 2006) was evident in the depth profiles of water temperature in Lake Bowen. The most stable water-column (highest relative thermal resistance to mixing) conditions occurred in Lake Bowen during the August to September 2005 survey. The least stable water-column (destratified) conditions occurred in Lake Bowen during the October 2006 survey and Reservoir #1 during all three surveys. Changes with depth in dissolved oxygen (decreased with depth to near anoxic conditions in the hypolimnion), pH (decreased with depth), and specific conductance (increased with depth) along with thermal stratification indicated Lake Bowen was exhibiting characteristics common to both mesotrophic and eutrophic conditions. Nutrient dynamics were different in Lake Bowen during the May 2006 survey from those during the August to September 2005 and October 2006 surveys. Total organic nitrogen concentrations (total Kjeldahl nitrogen minus ammonia) remained relatively constant within the surveys and ranged from 0.15 to 0.36 milligram per liter during the period of study. Nitrate was the dominant inorganic species of nitrogen during May 2006. Ammonia was the dominant species during the August to September 2005 and October 2006 surveys. During the August and September 2005 survey, ammonia was detected only in bottom samples collected in the near anoxic hypolimnion, but during the October 2006 survey, ammonia was detected under destratified conditions in surface and bottom samples. In Lake Bowen, total phosphorus concentrations in bottom samples did not exhibit the dramatic, high values during the May 2006 and October 2006 surveys (0.009 to 0.014 milligram per liter) that were identified for the August to September 2005 survey (0.022 to 0.034 milligram per liter). Chlorophyll a concentrations appeared to vary with the species of inorganic nitrogen. Greater chlorophyll a concentrations were identified in samples from the May 2006 survey (6.8 to 15 micrograms per liter) than in the August to September 2005 (1.2 to 6.4 micrograms per liter) and October surveys (5.6 to 8.2 micrograms per liter) at all sites in Lake Bowen and Reservoir #1. For the three limnological surveys, surface concentrations of chlorophyll a and total phosphorus were well below established numerical criteria for South Carolina. In general, the computed trophic state indices indicated that mesotrophic conditions were present in Lake Bowen and Reservoir #1. The total nitrogen to total phosphorus ratios in Lake Bowen and Reservoir #1 were below 22:1 for the August to September 2005 survey, indicating a high probability of dominance by nitrogen-fixing cyanobacteria. Ratios during the May and October 2006 surveys at

Relationship between Chlorophyll a Concentration, Light Attenuation and Diving Depth of the Southern Elephant Seal Mirounga leonina

PubMed Central

Jaud, Thomas; Dragon, Anne-Cécile; Garcia, Jade Vacquie; Guinet, Christophe

2012-01-01

Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K0.75) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K0.75 were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal’s dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES’s prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES’s prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency. PMID:23082166

Temporal variability of dissolved iron species in the mesopelagic zone at Ocean Station PAPA

NASA Astrophysics Data System (ADS)

Schallenberg, Christina; Ross, Andrew R. S.; Davidson, Ashley B.; Stewart, Gillian M.; Cullen, Jay T.

2017-08-01

Deposition of atmospheric aerosols to the surface ocean is considered an important mechanism for the supply of iron (Fe) to remote ocean regions, but direct observations of the oceanic response to aerosol deposition are sparse. In the high nutrient, low chlorophyll (HNLC) subarctic Pacific Ocean we observed a dissolved Fe and Fe(II) anomaly at depth that is best explained as the result of aerosol deposition from Siberian forest fires in May 2012. Interestingly, there was no evidence of enhanced dFe concentrations in surface waters, nor was there a detectable phytoplankton bloom in response to the suspected aerosol deposition. Dissolved Fe (dFe) and Fe(II) showed the strongest enhancement in the subsurface oxygen deficient zone (ODZ), where oxygen concentrations <50 μmol kg-1 are prevalent. In the upper 200 m, dFe concentrations were at or below historic background levels, consistent with a short residence time of aerosol particles in surface waters and possible scavenging loss of dFe. Aerosol toxicity and/or dominance of particle scavenging over dissolution of Fe in the upper water column may have contributed to the lack of a strong phytoplankton response.

Patterns of primary productivity and biomass in a coastal upwelling region

NASA Astrophysics Data System (ADS)

Small, Lawrence F.; Menzies, David W.

1981-02-01

Average distributions of chlorophyll α during upwelling in areas of smooth bathymetry off Oregon have been computed from historical data. Chlorophyll concentrations in cross-shelf sections over the Oregon continental shelf (44°40'N) were similar to those in cross-shelf sections off northwest Africa during JOINT-1 studies but differed from those in similar sections over an adjacent narrow region of the Oregon shelf (44°55'N to 45°12'N). The fact that larger concentration differences can occur along short sections of one coastline than between upwelling regions half a world apart bears on the time and space scales of sampling and might have bearing on the support and distributions of other trophic levels. Relationships between the local winds and the broader-scale BAKUN (1975) upwelling indices were used to classify various phytoplankton biomass and primary productivity distributions according to whether they were in strong upwelling steady state, weak upwelling steady state, or one of two transition states. The upwelling steady state conforms to the 'upwelling event' scale (about 3 to 10 days) of WALSH, WHITLEDGE, KELLEY, HUNTSMAN and PILLSBURY (1977) and the transition state of approximately one-day duration might specify the critical scale for driving the upwelling off Oregon. Under strong steady-state upwelling in early summer a single band of high primary productivity and biomass develops in the surface layer parallel to the bottom contours, but under similar upwelling conditions in later summer a two-celled zonal circulation occurs and two parallel bands develop. Our strong upwelling distributions are discussed in light of current models of the Oregon upwelling system. Maintenance of biological properties through time in the upwelling bands is also discussed. Under weak steady-state upwelling the primary productivity and biomass bands are farther inshore or immediately against the coast. Productivity in the weak upwelling bands can be twice that of the strong upwelling bands and often 20 times that in surrounding water. Under transient conditions in which the local winds are favorable for strong upwelling but the slower-responding Bakun index indicates weak upwelling, chlorophyll distributions change within a day to resemble distributions during strong steady-state upwelling. Under transient conditions in which the local winds weaken dramatically but the Bakun index still indicates strong upwelling, chlorophyll concentrations are high and widely distributed throughout the upwelling region.

Integrated satellite data fusion and mining for monitoring lake water quality status of the Albufera de Valencia in Spain.

PubMed

Doña, Carolina; Chang, Ni-Bin; Caselles, Vicente; Sánchez, Juan M; Camacho, Antonio; Delegido, Jesús; Vannah, Benjamin W

2015-03-15

Lake eutrophication is a critical issue in the interplay of water supply, environmental management, and ecosystem conservation. Integrated sensing, monitoring, and modeling for a holistic lake water quality assessment with respect to multiple constituents is in acute need. The aim of this paper is to develop an integrated algorithm for data fusion and mining of satellite remote sensing images to generate daily estimates of some water quality parameters of interest, such as chlorophyll a concentrations and water transparency, to be applied for the assessment of the hypertrophic Albufera de Valencia. The Albufera de Valencia is the largest freshwater lake in Spain, which can often present values of chlorophyll a concentration over 200 mg m(-3) and values of transparency (Secchi Disk, SD) as low as 20 cm. Remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat Thematic Mapper (TM) and Enhance Thematic Mapper (ETM+) images were fused to carry out an integrative near-real time water quality assessment on a daily basis. Landsat images are useful to study the spatial variability of the water quality parameters, due to its spatial resolution of 30 m, in comparison to the low spatial resolution (250/500 m) of MODIS. While Landsat offers a high spatial resolution, the low temporal resolution of 16 days is a significant drawback to achieve a near real-time monitoring system. This gap may be bridged by using MODIS images that have a high temporal resolution of 1 day, in spite of its low spatial resolution. Synthetic Landsat images were fused for dates with no Landsat overpass over the study area. Finally, with a suite of ground truth data, a few genetic programming (GP) models were derived to estimate the water quality using the fused surface reflectance data as inputs. The GP model for chlorophyll a estimation yielded a R(2) of 0.94, with a Root Mean Square Error (RMSE) = 8 mg m(-3), and the GP model for water transparency estimation using Secchi disk showed a R(2) of 0.89, with an RMSE = 4 cm. With this effort, the spatiotemporal variations of water transparency and chlorophyll a concentrations may be assessed simultaneously on a daily basis throughout the lake for environmental management. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Effects of NaCl stress on photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of Pistacia chinensis leaves].

PubMed

Li, Xu-Xin; Liu, Bing-Xiang; Guo, Zhi-Tao; Chang, Yue-Xia; He, Lei; Chen, Fang; Lu, Bing-She

2013-09-01

By using fast chlorophyll fluorescence induction dynamics analysis technique (JIP-test), this paper studied the photosynthesis characteristics and fast chlorophyll fluorescence induction dynamics of 1-year old Pistacia chinensis seedlings under the stress of NaCl at the concentrations 0% (CK), 0.15%, 0.3%, 0.45%, and 0.6%. With the increasing concentration of NaCl, the contents of Chl a, Chl b, and Chl (a+b) in the seedlings leaves decreased, the Chl a/b ratio decreased after an initial increase, and the carotenoid content increased. The net photosynthetic rate (P(n)) and stomatal conductance (g(s)) decreased gradually with increasing NaCl concentration. The decrease of P(n) was mainly attributed to the stomatal limitation when the NaCl concentration was lower than 0.3%, and to the non-stomatal limitation when the NaCl concentration was higher than 0.3%. The trapped energy flux per RC (TR0/CS0), electron transport flux per RC (ET0/CS0), density of RCs (RC/CS0), and yield or flux ratio (psi(0) or phi(E0)) decreased, but the absorption flux per CS (ABS/CS0) and the K phase (W(k)) and J phase (V) in the O-J-I-P chlorophyll fluorescence induction curves increased distinctly, indicating that NaCl stress damaged the leaf oxygen-evolving complex (OEC), donor sides, and PS II reaction centers. When the NaCl concentration reached 0.3%, the maximum photochemical efficiency (F(v)/F(m)) and performance index (PI(ABS)) decreased 17.7% and 36.6%, respectively, as compared with the control.

Ecotoxicity of two organophosphate pesticides chlorpyrifos and dichlorvos on non-targeting cyanobacteria Microcystis wesenbergii.

PubMed

Sun, Kai-Feng; Xu, Xiang-Rong; Duan, Shun-Shan; Wang, You-Shao; Cheng, Hao; Zhang, Zai-Wang; Zhou, Guang-Jie; Hong, Yi-Guo

2015-10-01

Organophosphate pesticides (OPs), as a replacement for the organochlorine pesticides, are generally considered non-toxic to plants and algae. Chlorpyrifos and dichlorvos are two OPs used for pest control all over the world. In this study, the dose-response of cyanobacteria Microcystis wesenbergii on OPs exposure and the stimulating effect of OPs with and without phosphorus source were investigated. The results showed that high concentrations of chlorpyrifos and dichlorvos caused significant decrease of chlorophyll a content. The median inhibitory concentrations (EC50) of chlorpyrifos and dichlorvos at 96 h were 15.40 and 261.16 μmol L(-1), respectively. Growth of M. wesenbergii under low concentration of OPs (ranged from 1/10,000 to 1/20 EC50), was increased by 35.85 % (chlorpyrifos) and 41.83 % (dichlorvos) at 120 h, respectively. Correspondingly, the highest enhancement on the maximum quantum yield (F v/F m) was 4.20 % (24 h) and 9.70 % (48 h), respectively. Chlorophyll fluorescence kinetics, known as O-J-I-P transients, showed significant enhancements in the O-J, J-I, and I-P transients under low concentrations of dichlorvos at 144 h, while enhancements of chlorophyll fluorescence kinetics induced by low concentrations of chlorpyrifos were only observed in the J-I transient at 144 h. Significant decreases of chlorophyll content, F v/F m and O-J-I-P transients with OPs as sole phosphorus source were found when they were compared with inorganic phosphate treatments. The results demonstrated an evidently hormetic dose-response of M. wesenbergii to both chlorpyrifos and dichlorvos, where high dose (far beyond environmental concentrations) exposure caused growth inhibition and low dose exposure induced enhancement on physiological processes. The stimulating effect of two OPs on growth of M. wesenbergii was negligible under phosphate limitation.

Does Primary Productivity Turn Up the Volume? Exploring the Relationship Between Chlorophyll a and the Soundscape of Coral Reefs in the Pacific.

PubMed

Fisher-Pool, Pollyanna I; Lammers, Marc O; Gove, Jamison; Wong, Kevin B

2016-01-01

Chlorophyll is the basis for ecosystem productivity in most marine environments. We report on an ongoing effort to examine whether ambient sounds are tied to chlorophyll levels. We hypothesized that an increase in food-web available energy will be distributed across trophic levels, eventually reaching sound-producing animals and increasing acoustic levels. To test our hypothesis, we compared reef environments to explore links between soundscapes and chlorophyll a concentrations. The study sites resided in disparate oceanographic regimes that experienced substantially different oceanographic conditions. We anticipated that the results would show differing patterns of primary productivity between sites and therefore would be reflected in the soundscapes.

Differences in functional traits between invasive and native Amaranthus species under different forms of N deposition

NASA Astrophysics Data System (ADS)

Wang, Congyan; Zhou, Jiawei; Liu, Jun; Jiang, Kun

2017-08-01

Differences in functional traits between invasive and native plant species are believed to determine the invasion success of the former. Increasing amounts of anthropogenic nitrogen (N) are continually deposited into natural ecosystems, which may change the relative occurrence of the different N deposition forms (such as NH4-N, NO3-N, and CO(NH2)2-N) naturally deposited. Under high N deposition scenarios, some invasive species may grow faster, gaining advantage over native species. In a greenhouse experiment, we grew invasive and native Amaranthus species from seed both alone and in competition under simulated N enriched environments with different forms of N over 3 months. Then, we measured different leaf traits (i.e., plant height, leaf length, leaf width, leaf shape index, specific leaf area (SLA), and leaf chlorophyll and N concentrations). Results showed that the competition intensity between A. retroflexus and A. tricolor decreased under N deposition. This may be due to the large functional divergence between A. retroflexus and A. tricolor under simulated N deposition. Phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus were significantly lower than in A. tricolor. The lower range of phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may indicate a fitness cost for plastic functional traits under adverse environments. The restricted phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may also stabilize leaf construction costs and the growth rate. Meanwhile, the two Amaranthus species possessed greater plasticity in leaf N concentration under NO3-N fertilization, which enhanced their competitiveness.

Differences in functional traits between invasive and native Amaranthus species under different forms of N deposition.

PubMed

Wang, Congyan; Zhou, Jiawei; Liu, Jun; Jiang, Kun

2017-08-01

Differences in functional traits between invasive and native plant species are believed to determine the invasion success of the former. Increasing amounts of anthropogenic nitrogen (N) are continually deposited into natural ecosystems, which may change the relative occurrence of the different N deposition forms (such as NH 4 -N, NO 3 -N, and CO(NH 2 ) 2 -N) naturally deposited. Under high N deposition scenarios, some invasive species may grow faster, gaining advantage over native species. In a greenhouse experiment, we grew invasive and native Amaranthus species from seed both alone and in competition under simulated N enriched environments with different forms of N over 3 months. Then, we measured different leaf traits (i.e., plant height, leaf length, leaf width, leaf shape index, specific leaf area (SLA), and leaf chlorophyll and N concentrations). Results showed that the competition intensity between A. retroflexus and A. tricolor decreased under N deposition. This may be due to the large functional divergence between A. retroflexus and A. tricolor under simulated N deposition. Phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus were significantly lower than in A. tricolor. The lower range of phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may indicate a fitness cost for plastic functional traits under adverse environments. The restricted phenotypic plasticity of SLA and leaf chlorophyll concentration of A. retroflexus may also stabilize leaf construction costs and the growth rate. Meanwhile, the two Amaranthus species possessed greater plasticity in leaf N concentration under NO 3 -N fertilization, which enhanced their competitiveness.

Seasonal variability of chlorophyll-a and oceanographic conditions in Sabah waters in relation to Asian monsoon--a remote sensing study.

PubMed

Abdul-Hadi, Alaa; Mansor, Shattri; Pradhan, Biswajeet; Tan, C K

2013-05-01

A study was conducted to investigate the influence of Asian monsoon on chlorophyll-a (Chl-a) content in Sabah waters and to identify the related oceanographic conditions that caused phytoplankton blooms at the eastern and western coasts of Sabah, Malaysia. A series of remote sensing measurements including surface Chl-a, sea surface temperature, sea surface height anomaly, wind speed, wind stress curl, and Ekman pumping were analyzed to study the oceanographic conditions that lead to large-scale nutrients enrichment in the surface layer. The results showed that the Chl-a content increased at the northwest coast from December to April due to strong northeasterly wind and coastal upwelling in Kota Kinabalu water. The southwest coast (Labuan water) maintained high concentrations throughout the year due to the effect of Padas River discharge during the rainy season and the changing direction of Baram River plume during the northeast monsoon (NEM). However, with the continuous supply of nutrients from the upwelling area, the high Chl-a batches were maintained at the offshore water off Labuan for a longer time during NEM. On the other side, the northeast coast illustrated a high Chl-a in Sandakan water during NEM, whereas the northern tip off Kudat did not show a pronounced change throughout the year. The southeast coast (Tawau water) was highly influenced by the direction of the surface water transport between the Sulu and Sulawesi Seas and the prevailing surface currents. The study demonstrates the presence of seasonal phytoplankton blooms in Sabah waters which will aid in forecasting the possible biological response and could further assist in marine resource managements.

Remote Sensing of Ocean Color

NASA Astrophysics Data System (ADS)

Dierssen, Heidi M.; Randolph, Kaylan

The oceans cover over 70% of the earth's surface and the life inhabiting the oceans play an important role in shaping the earth's climate. Phytoplankton, the microscopic organisms in the surface ocean, are responsible for half of the photosynthesis on the planet. These organisms at the base of the food web take up light and carbon dioxide and fix carbon into biological structures releasing oxygen. Estimating the amount of microscopic phytoplankton and their associated primary productivity over the vast expanses of the ocean is extremely challenging from ships. However, as phytoplankton take up light for photosynthesis, they change the color of the surface ocean from blue to green. Such shifts in ocean color can be measured from sensors placed high above the sea on satellites or aircraft and is called "ocean color remote sensing." In open ocean waters, the ocean color is predominantly driven by the phytoplankton concentration and ocean color remote sensing has been used to estimate the amount of chlorophyll a, the primary light-absorbing pigment in all phytoplankton. For the last few decades, satellite data have been used to estimate large-scale patterns of chlorophyll and to model primary productivity across the global ocean from daily to interannual timescales. Such global estimates of chlorophyll and primary productivity have been integrated into climate models and illustrate the important feedbacks between ocean life and global climate processes. In coastal and estuarine systems, ocean color is significantly influenced by other light-absorbing and light-scattering components besides phytoplankton. New approaches have been developed to evaluate the ocean color in relationship to colored dissolved organic matter, suspended sediments, and even to characterize the bathymetry and composition of the seafloor in optically shallow waters. Ocean color measurements are increasingly being used for environmental monitoring of harmful algal blooms, critical coastal habitats (e.g., seagrasses, kelps), eutrophication processes, oil spills, and a variety of hazards in the coastal zone.

Chlorophyll content retrieval from hyperspectral remote sensing imagery.

PubMed

Yang, Xiguang; Yu, Ying; Fan, Wenyi

2015-07-01

Chlorophyll content is the essential parameter in the photosynthetic process determining leaf spectral variation in visible bands. Therefore, the accurate estimation of the forest canopy chlorophyll content is a significant foundation in assessing forest growth and stress affected by diseases. Hyperspectral remote sensing with high spatial resolution can be used for estimating chlorophyll content. In this study, the chlorophyll content was retrieved step by step using Hyperion imagery. Firstly, the spectral curve of the leaf was analyzed, 25 spectral characteristic parameters were identified through the correlation coefficient matrix, and a leaf chlorophyll content inversion model was established using a stepwise regression method. Secondly, the pixel reflectance was converted into leaf reflectance by a geometrical-optical model (4-scale). The three most important parameters of reflectance conversion, including the multiple scattering factor (M 0 ), and the probability of viewing the sunlit tree crown (P T ) and the background (P G ), were estimated by leaf area index (LAI), respectively. The results indicated that M 0 , P T , and P G could be described as a logarithmic function of LAI, with all R (2) values above 0.9. Finally, leaf chlorophyll content was retrieved with RMSE = 7.3574 μg/cm(2), and canopy chlorophyll content per unit ground surface area was estimated based on leaf chlorophyll content and LAI. Chlorophyll content mapping can be useful for the assessment of forest growth stage and diseases.

Fabrication of dye-sensitized solar cell using chlorophylls pigment from sargassum

NASA Astrophysics Data System (ADS)

Ridwan, M. A.; Noor, E.; Rusli, M. S.; Akhiruddin

2018-04-01

Dye-sensitized solar cell (DSSC) is a new generation of the solar cell. Its development in the dye-sensitized system is varied. Natural dyes have been the choice in developing DSSC. This study used a dye-sensitized chlorophyll pigment from Sargassum sp. as a dye-sensitized solar cell. This study aims to obtain chlorophyll pigment extract to be used as a dye in DSSC and to obtain the best energy conversion efficiency from DSSC. The chlorophyll pigments were extracted using APHA method (2012), and the TiO2 coating method used was doctor blade method. The two fabricated cells have an area of 1 cm2 immersed with chlorophyll dye for 30 hours. Then these cells were tested using direct sun radiation. The concentration value of chlorophyll in acetone solution was 61.176 mg/L. The efficiency value obtained was 1.50% with VOC of 241 mV, ISC 2.9 x 10-4 mA and fill factor 0.432.

Leaf Optical Properties in Higher Plants: Linking Spectral Characteristics to Stress and Chlorophyll Concentration

NASA Technical Reports Server (NTRS)

Carter, Gregory A.; Knapp, Alan K.

2000-01-01

A number of studies have linked responses in leaf spectral reflectance, transmittance or absorptance to physiological stress. A variety of stressors including dehydration, flooding,freezing, ozone, herbicides, competition, disease, insects and deficiencies in ectomycorrhizal development and N fertilization have been imposed on species ranging from grasses to conifers and deciduous trees. In this cases, the maximum difference in reflectance within the 400 - 850 nm wavelength range between control and stressed states occurred as a reflectance increase at wavelength near 700 nm. In studies that included transmittance and absorptance as well as reflectance, maximum differences occurred as increases and decreases, respectively, near 700 nm. This common optical response to stress could be simulated closely by varying the chlorophyll concentrations in senescent leaves of five species. The optical response to stress near 700 nm, as well as corresponding changes in reflectance that occur in the green-yellow spectrum, can be explained by the general tendency of stress to reduce leaf chlorophyll concentration.

Effect of phytoplankton biomass in seawater on chemical properties of sea spray aerosols.

PubMed

Park, Jiyeon; Kim, Dohyung; Lee, Kwangyul; Han, Seunghee; Kim, Hyunji; Williams, Leah R; Joo, Hung Soo; Park, Kihong

2016-09-15

This study is to investigate the effect of biological seawater properties on sea spray aerosols (SSA). Concentrations of chlorophyll-a and bacteria were measured at coastal site in Korea in fall and summer seasons. Also, aerosol mass spectrometer (AMS) was used to determine chemical constituents (organics, sulfate, nitrate, ammonium, and chloride) of non-refractory submicrometer aerosols sprayed from seawaters using a bubble bursting system. The average concentration of chlorophyll-a in seawater in fall was 1.75±0.78μg/l, whereas it significantly increased to 5.11±2.16μg/l in summer. It was found that the fraction of organics in the submicrometer SSA was higher in summer (68%) than fall (49%), and that the organic fraction in the SSA increased as the concentration of chlorophyll-a increased in seawater, suggesting that the high phytoplankton biomass in seawater could lead to the enhancement of organic species in the SSA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dynamics of limnological parameters in reservoirs: A case study in South Brazil using remote sensing and meteorological data.

PubMed

Breunig, Fábio Marcelo; Pereira Filho, Waterloo; Galvão, Lênio Soares; Wachholz, Flávio; Cardoso, Maria Angélica Gonçalves

2017-01-01

Reservoirs are important in Brazil for the production of hydroelectric power and human water consumption. The objective was to evaluate the variability of total suspended solids (TSS) and chlorophyll-a as well as the rainfall/temperature and land use impacts on these optically active constituents (OAC). The study area is the Passo Real reservoir in south Brazil. The methodology was divided in four steps. First, we used wavelet to detect anomalous periods of rainfall and temperature (2002-2014). Second, we carried out 12 field campaigns to obtain in situ measurements for limnological characterization (2009-2010). The third step was the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra and Aqua satellites data corrected and non-corrected for bidirectional effects. Finally, we evaluated potential drivers of OAC changes over time using cross-correlation analysis. The results showed a decrease in the TSS and chlorophyll-a concentrations from the upper to the lower streams of the reservoir. The exponential regression between the MODIS red reflectance and TSS had an adjusted r 2 of 0.63. It decreased to 0.53 for the relationship between the green reflectance and chlorophyll-a. MODIS data corrected for bidirectional effects provided better OAC estimates than non-corrected data. The validation of MODIS TSS and chlorophyll-a estimates using a separate set of measurements showed a RMSE of 2.98mg/l and 2.33μg/l, respectively. MODIS estimates indicated a gradual transition in OAC from the upper to the lower streams in agreement with the patterns observed using field limnological data. The analysis of land use (greenness) showed two well-defined crop cycles per year. The highest seasonal concentrations of TSS and chlorophyll-a were observed in December and the lowest concentrations in April. Despite the interrelationships between both factors, our cross-correlation analysis indicated that the great concentrations of TSS and chlorophyll-a were primarily controlled by rainfall and secondarily by land use. Copyright © 2016 Elsevier B.V. All rights reserved.

Seasonal Progression and Interannual Variability of Nutrient and Chlorophyll-a Distributions in the Northern Gulf of Alaska, 1998-2010

NASA Astrophysics Data System (ADS)

Trahanovsky, K.; Whitledge, T. E.

2016-02-01

We examined nutrient and chlorophyll-a (chl) concentrations from bottle samples collected from 0-50 m depth in the Northern Gulf of Alaska along the Seward Line transect on 56 cruises from 1998-2010. We computed monthly average concentrations of macronutrients (N, P, and Si) and chlorophyll-a by depth at four major stations along the transect to describe the regular seasonal progression of the nutricline and typical water column distributions of chlorophyll-a in this seasonally productive, downwelling coastal zone. The across-shelf transect displayed two different patterns of seasonal progression clearly associated with the Alaska Coastal Current (ACC) and Alaskan Stream (AS) current systems. The annual cycle of nutrient drawdown and replenishment is remarkably consistent from year to year within each system and is well correlated with chl measurements. The spring bloom begins earlier and nutrient depletion is sustained longer in the near-shore ACC then in the AS system centered over the shelf break. Chlorophyll-a concentrations frequently peak at 10-20m depth in both systems during July through October, as nutrients remain depleted in the top 10m. Subsurface nutrients (20 - 50 m depth) begin to recover between July and August and then experience a secondary drawdown between August and October, consistent with higher chl levels observed during the fall bloom. Interannual variability in the progression of the nutricline and the relative contribution of subsurface chl to total chl is presented. Physical data demonstrate increasing stratification in this region due to climate change; the implications for nutrient dynamics and primary production are discussed.

How Diffusivity, Thermocline and Incident Light Intensity Modulate the Dynamics of Deep Chlorophyll Maximum in Tyrrhenian Sea

PubMed Central

Valenti, Davide; Denaro, Giovanni; Spagnolo, Bernardo; Conversano, Fabio; Brunet, Christophe

2015-01-01

During the last few years theoretical works have shed new light and proposed new hypotheses on the mechanisms which regulate the spatio-temporal behaviour of phytoplankton communities in marine pelagic ecosystems. Despite this, relevant physical and biological issues, such as effects of the time-dependent mixing in the upper layer, competition between groups, and dynamics of non-stationary deep chlorophyll maxima, are still open questions. In this work, we analyze the spatio-temporal behaviour of five phytoplankton populations in a real marine ecosystem by using a one-dimensional reaction-diffusion-taxis model. The study is performed, taking into account the seasonal variations of environmental variables, such as light intensity, thickness of upper mixed layer and profiles of vertical turbulent diffusivity, obtained starting from experimental findings. Theoretical distributions of phytoplankton cell concentration was converted in chlorophyll concentration, and compared with the experimental profiles measured in a site of the Tyrrhenian Sea at four different times (seasons) of the year, during four different oceanographic cruises. As a result we find a good agreement between theoretical and experimental distributions of chlorophyll concentration. In particular, theoretical results reveal that the seasonal changes of environmental variables play a key role in the phytoplankton distribution and determine the properties of the deep chlorophyll maximum. This study could be extended to other marine ecosystems to predict future changes in the phytoplankton biomass due to global warming, in view of devising strategies to prevent the decline of the primary production and the consequent decrease of fish species. PMID:25629963

Optical Remote Sensing Algorithm Validation using High-Frequency Underway Biogeochemical Measurements in Three Large Global River Systems

NASA Astrophysics Data System (ADS)

Kuhn, C.; Richey, J. E.; Striegl, R. G.; Ward, N.; Sawakuchi, H. O.; Crawford, J.; Loken, L. C.; Stadler, P.; Dornblaser, M.; Butman, D. E.

2017-12-01

More than 93% of the world's river-water volume occurs in basins impacted by large dams and about 43% of river water discharge is impacted by flow regulation. Human land use also alters nutrient and carbon cycling and the emission of carbon dioxide from inland reservoirs. Increased water residence times and warmer temperatures in reservoirs fundamentally alter the physical settings for biogeochemical processing in large rivers, yet river biogeochemistry for many large systems remains undersampled. Satellite remote sensing holds promise as a methodology for responsive regional and global water resources management. Decades of ocean optics research has laid the foundation for the use of remote sensing reflectance in optical wavelengths (400 - 700 nm) to produce satellite-derived, near-surface estimates of phytoplankton chlorophyll concentration. Significant improvements between successive generations of ocean color sensors have enabled the scientific community to document changes in global ocean productivity (NPP) and estimate ocean biomass with increasing accuracy. Despite large advances in ocean optics, application of optical methods to inland waters has been limited to date due to their optical complexity and small spatial scale. To test this frontier, we present a study evaluating the accuracy and suitability of empirical inversion approaches for estimating chlorophyll-a, turbidity and temperature for the Amazon, Columbia and Mississippi rivers using satellite remote sensing. We demonstrate how riverine biogeochemical measurements collected at high frequencies from underway vessels can be used as in situ matchups to evaluate remotely-sensed, near-surface temperature, turbidity, chlorophyll-a derived from the Landsat 8 (NASA) and Sentinel 2 (ESA) satellites. We investigate the use of remote sensing water reflectance to infer trophic status as well as tributary influences on the optical characteristics of the Amazon, Mississippi and Columbia rivers.

Phytoplankton class-specific primary production in the world's oceans: Seasonal and interannual variability from satellite observations

NASA Astrophysics Data System (ADS)

Uitz, Julia; Claustre, Hervé; Gentili, Bernard; Stramski, Dariusz

2010-09-01

We apply an innovative approach to time series data of surface chlorophyll from satellite observations with SeaWiFS (Sea-viewing Wide Field-of-view Sensor) to estimate the primary production associated with three major phytoplankton classes (micro-, nano-, and picophytoplankton) within the world's oceans. Statistical relationships, determined from an extensive in situ database of phytoplankton pigments, are used to infer class-specific vertical profiles of chlorophyll a concentration from satellite-derived surface chlorophyll a. This information is combined with a primary production model and class-specific photophysiological parameters to compute global seasonal fields of class-specific primary production over a 10-year period from January 1998 through December 2007. Microphytoplankton (mostly diatoms) appear as a major contributor to total primary production in coastal upwelling systems (70%) and temperate and subpolar regions (50%) during the spring-summer season. The contribution of picophytoplankton (e.g., prokaryotes) reaches maximum values (45%) in subtropical oligotrophic gyres. Nanophytoplankton (e.g., prymnesiophytes) provide a ubiquitous, substantial contribution (30-60%). Annual global estimates of class-specific primary production amount to 15 Gt C yr-1 (32% of total), 20 Gt C yr-1 (44%) and 11 Gt C yr-1 (24%) for micro-, nano-, and picophytoplankton, respectively. The analysis of interannual variations revealed large anomalies in class-specific primary production as compared to the 10-year mean cycle in both the productive North Atlantic basin and the more stable equatorial Pacific upwelling. Microphytoplankton show the largest range of variability of the three phytoplankton classes on seasonal and interannual time scales. Our results contribute to an understanding and quantification of carbon cycle in the ocean.

Seasonal changes in the chemistry and biology of a meromictic lake (Big Soda Lake, Nevada, U.S.A.)

USGS Publications Warehouse

Cloern, J.E.; Cole, B.E.; Oremland, R.S.

1983-01-01

Big Soda Lake is an alkaline, saline lake with a permanent chemocline at 34.5 m and a mixolimnion that undergoes seasonal changes in temperature structure. During the period of thermal stratification, from summer through fall, the epilimnion has low concentrations of dissolved inorganic nutrients (N, Si) and CH4, and low biomass of phytoplankton (chlorophyll a ca. 1 mgm -3). Dissolved oxygen disappears near the compensation depth for algal photosynthesis (ca. 20 m). Surface water is transparent so that light is present in the anoxic hypolimnion, and a dense plate of purple sulfur photosynthetic bacteria (Ectothiorhodospira vacuolata) is present just below 20 m (Bchl a ca. 200 mgm-3). Concentrations of N H4+, Si, and CH4 are higher in the hypolimnion than in the epilimnion. As the mixolimnion becomes isothermal in winter, oxygen is mixed down to 28 m. Nutrients (NH4+, Si) and CH4 are released from the hypolimnion and mix to the surface, and a diatom bloom develops in the upper 20 m (chlorophyll a > 40 mgm-3). The deeper mixing of oxygen and enhanced light attenuation by phytoplankton uncouple the anoxic zone and photic zone, and the plate of photosynthetic bacteria disappears (Bchl a ca.10mgm-3). Hence, seasonal changes in temperature distribution and mixing create conditions such that the primary producer community is alternately dominated by phytoplankton and photosynthetic bacteria: the phytoplankton may be nutrient-limited during periods of stratification and the photosynthetic bacteria are light-limited during periods of mixing. ?? 1983 Dr W. Junk Publishers.

A pilot project to detect and forecast harmful algal blooms in the northern Gulf of Mexico.

PubMed

Fisher, William S; Malone, Thomas C; Giattina, James D

2003-01-01

More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-driven, end-to-end (measurements to applications) observing system. A key strategy of the project is to coordinate existing state, federal and academic programs at an unprecedented level of collaboration and partnership. Resource managers charged with protection of public health and aquatic resources require immediate notice of algal events and a forecast of when, where and what adverse effects will likely occur. Further, managers require integrated analyses and interpretations, rather than raw data, to make effective decisions. Consequently, a functional observing system must collect and transform diverse measurements into usable forecasts. Data needed to support development of forecasts will include such properties as sea surface temperature, winds, currents and waves; precipitation and freshwater flows with related discharges of sediment and nutrients; salinity, dissolved oxygen, and chlorophyll concentrations (in vivo fluorescence); and remotely-sensed spatial images of sea surface chlorophyll concentrations. These data will be provided via a mixture of discrete and autonomous in situ sensing with near real-time data telemetry, and remote sensing from space (SeaWiFS), aircraft (hyperspectral imagery) or land (high-frequency radar). With calibration across these platforms, the project will ultimately provide a 4-dimensional visualization of harmful algae events in a time frame suitable to resource managers.

Significance of the Autumn Bloom within the Seasonal Cycle of Primary Production in a Temperate Continental Shelf Sea

NASA Astrophysics Data System (ADS)

Wihsgott, Juliane U.; Sharples, Jonathan; Hopkins, Joanne; Woodward, Malcolm; Greenwood, Naomi; Sivyer, Dave; Hull, Tom

2017-04-01

Autumnal phytoplankton blooms are considered characteristic features of the seasonal cycle of primary productivity in most temperate and subpolar oceans. While observations of their occurrence and strength have been documented extensively, their significance within the seasonal cycle of primary production is not well quantified. Our aim is to establish the role the autumn bloom plays within the seasonal cycle and estimate its contribution to the annual primary production of a temperate continental shelf. In particular, we will illustrate that the autumn bloom has the potential to be as productive as the well-studied summer sub-surface chlorophyll maximum (SCM) and the capacity to significantly contribute to the drawdown of atmospheric CO2. We do this by combining long-term, high resolution observations of water column structure, meteorological forcing, nitrate and chlorophyll fluorescence over the entire seasonal cycle observed in a temperate shelf sea. We present a new series of continuous measurements spanning 17 months (March 2014 - July 2015), which were collected in a temperate shelf sea on the North West European Shelf. A long-term mooring array recorded full depth vertical density structure, dynamics and meteorological data as well as surface chlorophyll fluorescence biomass and inorganic nutrient data over a full seasonal cycle at a station 120 km north-east from the continental shelf break. Eight process cruises supplied additional full depth profiles of chlorophyll fluorescence biomass and macronutrients. The breakdown of stratification in 2014 commenced in early October due to increased winds compared to summer months, and a predominantly negative net heat flux (the ocean lost heat to the overlying atmosphere). Vertical mixing in autumn not only transformed the vertical density structure but also the vertical structure of chlorophyll biomass and surface nutrients. The SCM became eroded and instead a vertically homogeneous profile of chlorophyll biomass established itself above the pycnocline. This increased mixing also led to replenishment of surface nutrients and drove enhanced growth, which was almost 4 times stronger than observed during the summer months: We find an increase in depth integrated chlorophyll biomass of ˜50 mg m-2 in autumn 2014 compared to values of ˜20 mg m-2 during the summers of 2014 and 2015.

The effects of wildfire on mercury and stable isotopes (δ(15)N, δ(13)C) in water and biota of small boreal, acidic lakes in southern Norway.

PubMed

Moreno, Clara E; Fjeld, Eirik; Lydersen, Espen

2016-03-01

Effects of wildfire on main water chemistry and mercury (Hg) in water and biota were studied during the first 4 post-fire years. After severe water chemical conditions during hydrological events a few months following the wildfire, the major water chemical parameters were close to pre-fire conditions 4 years after the fire. Concentrations of total Hg and methyl Hg in the surface water 4 years after the fire ranged between 1.17-2.63 ng L(-1) and 0.053-0.188 ng L(-1), respectively. Both variables were positive and strongly correlated with total organic carbon (TOC), TOC-related variables (color, UV absorbance), total phosphorous, and total iron. In addition, MeHg was positively correlated with total nitrogen and chlorophyll-a. The concurrence of increased concentrations of nutrients and chlorophyll-a in the lakes, the more enriched δ(15)N-signatures and higher Hg levels in fish 2 years after the fire, might be a result of the wildfire. However, natural factors as year-to-year variations in thermocline depth and suboxic status in the lakes make it difficult to draw any strong conclusions about wildfire effects on Hg in the biota from our investigated lakes.

A 2000-yr-long multi-proxy lacustrine record from eastern Baffin Island, Arctic Canada reveals first millennium AD cold period

NASA Astrophysics Data System (ADS)

Thomas, Elizabeth K.; Briner, Jason P.; Axford, Yarrow; Francis, Donna R.; Miller, Gifford H.; Walker, Ian R.

2011-05-01

We generate a multi-proxy sub-centennial-scale reconstruction of environmental change during the past two millennia from Itilliq Lake, Baffin Island, Arctic Canada. Our reconstruction arises from a finely subsectioned 210Pb- and 14C-dated surface sediment core and includes measures of organic matter (e.g., chlorophyll a; carbon-nitrogen ratio) and insect (Diptera: Chironomidae) assemblages. Within the past millennium, the least productive, and by inference coldest, conditions occurred ca. AD 1700-1850, late in the Little Ice Age. The 2000-yr sediment record also reveals an episode of reduced organic matter deposition during the 6th-7th century AD; combined with the few other records comparable in resolution that span this time interval from Baffin Island, we suggest that this cold episode was experienced regionally. A comparable cold climatic episode occurred in Alaska and western Canada at this time, suggesting that the first millennium AD cold climate anomaly may have occurred throughout the Arctic. Dramatic increases in aquatic biological productivity at multiple trophic levels are indicated by increased chlorophyll a concentrations since AD 1800 and chironomid concentrations since AD 1900, both of which have risen to levels unprecedented over the past 2000 yr.

Evaluation of photosynthetic efficacy and CO2 removal of microalgae grown in an enriched bicarbonate medium.

PubMed

Abinandan, S; Shanthakumar, S

2016-06-01

Bicarbonate species in the aqueous phase is the primary source for CO 2 for the growth of microalgae. The potential of carbon dioxide (CO 2 ) fixation by Chlorella pyrenoidosa in enriched bicarbonate medium was evaluated. In the present study, effects of parameters such as pH, sodium bicarbonate concentration and inoculum size were assessed for the removal of CO 2 by C. pyrenoidosa under mixotrophic condition. Central composite design tool from response surface methodology was used to validate statistical methods in order to study the influence of these parameters. The obtained results reveal that the maximum removal of CO 2 was attained at pH 8 with sodium bicarbonate concentration of 3.33 g/l, and inoculum size of 30 %. The experimental results were statistically significant with R 2 value of 0.9527 and 0.960 for CO 2 removal and accumulation of chlorophyll content, respectively. Among the various interactions, interactive effects between the parameters pH and inoculum size was statistically significant (P < 0.05) for CO 2 removal and chlorophyll accumulation. Based on the studies, the application of C. pyrenoidosa as a potential source for carbon dioxide removal at alkaline pH from bicarbonate source is highlighted.

The formation processes of phytoplankton growth and decline in mesoscale eddies in the western North Pacific Ocean

NASA Astrophysics Data System (ADS)

Chang, Yu-Lin; Miyazawa, Yasumasa; Oey, Lie-Yauw; Kodaira, Tsubasa; Huang, Shihming

2017-05-01

In this study, we investigate the processes of phytoplankton growth and decline in mesoscale eddies in the western North Pacific Ocean based on the in situ chlorophyll data obtained from 52 cruises conducted by the Japan Meteorological Agency together with idealized numerical simulations. Both the observation and model results suggest that chlorophyll/phytoplankton concentrations are higher in cold than in warm eddies in near-surface water (z > -70 m). In the idealized simulation, the isopycnal movements associated with upwelling/downwelling transport phytoplankton and nutrients to different vertical depths during eddy formation (stage A). Phytoplankton and nutrients in cold eddies is transported toward shallower waters while those in warm eddies move toward deeper waters. In the period after the eddy has formed (stage B), sunlight and initially upwelled nutrients together promote the growth of phytoplankton in cold eddies. Phytoplankton in warm eddies decays due to insufficient sunlight in deeper waters. In stage B, upwelling and downwelling coexist in both warm and cold eddies, contributing nearly equally to vertical displacement. The upwelling/downwelling-induced nitrate flux accounts for a small percentage (˜3%) of the total nitrate flux in stage B. The vertical velocity caused by propagating eddies, therefore, is not the primary factor causing differences in phytoplankton concentrations between stage-B warm and cold eddies.

Predicting crappie recruitment in Ohio reservoirs with spawning stock size, larval density, and chlorophyll concentrations

USGS Publications Warehouse

Bunnell, David B.; Hale, R. Scott; Vanni, Michael J.; Stein, Roy A.

2006-01-01

Stock-recruit models typically use only spawning stock size as a predictor of recruitment to a fishery. In this paper, however, we used spawning stock size as well as larval density and key environmental variables to predict recruitment of white crappies Pomoxis annularis and black crappies P. nigromaculatus, a genus notorious for variable recruitment. We sampled adults and recruits from 11 Ohio reservoirs and larvae from 9 reservoirs during 1998-2001. We sampled chlorophyll as an index of reservoir productivity and obtained daily estimates of water elevation to determine the impact of hydrology on recruitment. Akaike's information criterion (AIC) revealed that Ricker and Beverton-Holt stock-recruit models that included chlorophyll best explained the variation in larval density and age-2 recruits. Specifically, spawning stock catch per effort (CPE) and chlorophyll explained 63-64% of the variation in larval density. In turn, larval density and chlorophyll explained 43-49% of the variation in age-2 recruit CPE. Finally, spawning stock CPE and chlorophyll were the best predictors of recruit CPE (i.e., 74-86%). Although larval density and recruitment increased with chlorophyll, neither was related to seasonal water elevation. Also, the AIC generally did not distinguish between Ricker and Beverton-Holt models. From these relationships, we concluded that crappie recruitment can be limited by spawning stock CPE and larval production when spawning stock sizes are low (i.e., CPE , 5 crappies/net-night). At higher levels of spawning stock sizes, spawning stock CPE and recruitment were less clearly related. To predict recruitment in Ohio reservoirs, managers should assess spawning stock CPE with trap nets and estimate chlorophyll concentrations. To increase crappie recruitment in reservoirs where recruitment is consistently poor, managers should use regulations to increase spawning stock size, which, in turn, should increase larval production and recruits to the fishery.

Seasonal patterns in nutrients, carbon, and algal responses in wadeable streams within three geographically distinct areas of the United States, 2007-08

USGS Publications Warehouse

Lee, Kathy E.; Lorenz, David L.; Petersen, James C.; Greene, John B.

2012-01-01

The U.S. Geological Survey determined seasonal variability in nutrients, carbon, and algal biomass in 22 wadeable streams over a 1-year period during 2007 or 2008 within three geographically distinct areas in the United States. The three areas are the Upper Mississippi River Basin (UMIS) in Minnesota, the Ozark Plateaus (ORZK) in southern Missouri and northern Arkansas, and the Upper Snake River Basin (USNK) in southern Idaho. Seasonal patterns in some constituent concentrations and algal responses were distinct. Nitrate concentrations were greatest during the winter in all study areas potentially because of a reduction in denitrification rates and algal uptake during the winter, along with reduced surface runoff. Decreases in nitrate concentrations during the spring and summer at most stream sites coincided with increased streamflow during the snowmelt runoff or spring storms indicating dilution. The continued decrease in nitrate concentrations during summer potentially is because of a reduction in nitrate inputs (from decreased surface runoff) or increases in biological uptake. In contrast to nitrate concentrations, ammonia concentrations varied among study areas. Ammonia concentration trends were similar at UMIS and USNK sampling sites with winter peak concentrations and rapid decreases in ammonia concentrations by spring or early summer. In contrast, ammonia concentrations at OZRK sampling sites were more variable with peak concentrations later in the year. Ammonia may accumulate in stream water in the winter under ice and snow cover at the UMIS and USNK sites because of limited algal metabolism and increased mineralization of decaying organic matter under reducing conditions within stream bottom sediments. Phosphorus concentration patterns and the type of phosphorus present changes with changing hydrologic conditions and seasons and varied among study areas. Orthophosphate concentrations tended to be greater in the summer at UMIS sites, whereas total phosphorus concentrations at most UMIS and USNK sites peaked in the spring during runoff and then decreased through the remainder of the sampling period. Total phosphorus and orthophosphate concentrations in OZRK streams peaked during summer indicating a runoff-based source of both nutrients. Orthophosphate concentrations may increase in streams in the late summer when surface runoff composes less of total streamflow, and when groundwater containing orthophosphate becomes a more dominant source in streams during lower flows. Seston chlorophyll a concentrations were greatest early in the growing season (spring), whereas the spring runoff events coincided with reductions in benthic algal chlorophyll a biomass likely because of scour of benthic algae from the channel bottom that are entrained in the water column during that period. Nitrate, ammonia, and orthophosphate concentrations also decreased during that same period, indicating dilution in the spring during runoff events. The data from this study indicate that the source of water (surface runoff or groundwater) to a stream and the intensity of major runoff events are important factors controlling instream concentrations. Biological processes appear to affect nutrient concentrations during more stable lower flow periods in later summer, fall, and winter when residence time of water in a channel is longer, which allows more time for biological uptake and transformations. Management of nutrient conditions in streams is challenging and requires an understanding of multiple factors that affect in-stream nutrient concentrations and biological uptake and growth.

Satellite Remote Sensing of Chlorophyll a in Support of Nutrient Management in the Neuse and Tar-Pamlico River Estuaries

EPA Science Inventory

The North Carolina Environmental Management Commission (EMC) has adopted as a water quality standard that chlorophyll a concentration should not exceed 40 ug/L in sounds, estuaries and other slow-moving waters. Exceedances require regulators to develop a Total Maximum Daily Limit...

Satellite remote sensing of chlorophyll a in support of nutrient management in the Neuse and Tar-Pamlico River (North Carolina) estuaries

EPA Science Inventory

The North Carolina Environmental Management Commission (EMC) has adopted as a water quality standard that chlorophyll a concentration should not exceed 40 ug/L in sounds, estuaries and other slow-moving waters. Exceedances require regulators to develop a Total Maximum Daily Limit...

Gamma radiation effects on seed germination, growth and pigment content, and ESR study of induced free radicals in maize (Zea mays).

PubMed

Marcu, Delia; Damian, Grigore; Cosma, Constantin; Cristea, Victoria

2013-09-01

The effects of gamma radiation are investigated by studying plant germination, growth and development, and biochemical characteristics of maize. Maize dry seeds are exposed to a gamma source at doses ranging from 0.1 to 1 kGy. Our results show that the germination potential, expressed through the final germination percentage and the germination index, as well as the physiological parameters of maize seedlings (root and shoot lengths) decreased by increasing the irradiation dose. Moreover, plants derived from seeds exposed at higher doses (≤0.5 kGy) did not survive more than 10 days. Biochemical differences based on photosynthetic pigment (chlorophyll a, chlorophyll b, carotenoids) content revealed an inversely proportional relationship to doses of exposure. Furthermore, the concentration of chlorophyll a was higher than chlorophyll b in both irradiated and non-irradiated seedlings. Electron spin resonance spectroscopy used to evaluate the amount of free radicals induced by gamma ray treatment demonstrates that the relative concentration of radiation-induced free radicals depends linearly on the absorbed doses.

Impact of chlorophyll bias on the tropical Pacific mean climate in an earth system model

NASA Astrophysics Data System (ADS)

Lim, Hyung-Gyu; Park, Jong-Yeon; Kug, Jong-Seong

2017-12-01

Climate modeling groups nowadays develop earth system models (ESMs) by incorporating biogeochemical processes in their climate models. The ESMs, however, often show substantial bias in simulated marine biogeochemistry which can potentially introduce an undesirable bias in physical ocean fields through biogeophysical interactions. This study examines how and how much the chlorophyll bias in a state-of-the-art ESM affects the mean and seasonal cycle of tropical Pacific sea-surface temperature (SST). The ESM used in the present study shows a sizeable positive bias in the simulated tropical chlorophyll. We found that the correction of the chlorophyll bias can reduce the ESM's intrinsic cold SST mean bias in the equatorial Pacific. The biologically-induced cold SST bias is strongly affected by seasonally-dependent air-sea coupling strength. In addition, the correction of chlorophyll bias can improve the annual cycle of SST by up to 25%. This result suggests a possible modeling approach in understanding the two-way interactions between physical and chlorophyll biases by biogeophysical effects.

Skylab investigation of the upwelling off the Northwest coast of Africa

NASA Technical Reports Server (NTRS)

Szekielda, K. H.; Suszkowski, D. J.; Tabor, P. S.

1975-01-01

The upwelling off the NW coast of Africa in the vicinity of Cape Blanc was studied in February - March 1974 from aircraft and in September 1973 from Skylab. The aircraft study was designed to determine the effectiveness of a differential radiometer in quantifying surface chlorophyll concentrations. Photographic images of the S190A Multispectral Camera and the S190B Earth Terrain Camera from Skylab were used to study distributional patterns of suspended material and to locate ocean color boundaries. The thermal channel of the S192 Multispectral Scanner was used to map sea-surface temperature distributions offshore of Cape Blanc. Correlating ocean color changes with temperature gradients is an effective method of qualitatively estimating biological productivity in the upwelling region off Africa.

Spatio-temporal variability of upwelling along the southwest coast of India based on satellite observations

NASA Astrophysics Data System (ADS)

Jayaram, Chiranjivi; Kumar, P. K. Dinesh

2018-03-01

Upwelling phenomenon along the eastern boundaries of global ocean has received greater attention in the recent times due to its environmental and economic significance in the global warming and the scenario of changing climate as opined by IPCC AR5. In this context, the availabile satellite data on sea surface winds, sea surface temperature (SST), sea level anomaly (SLA) and chlorophyll-a concentration (Chl-a), for the period 1981-2016 were analyzed to identify the coastal upwelling pattern in the Southeastern Arabian Sea (SEAS). Synergistic approach, using winds, SST, SLA and Chl-a revealed that strong upwelling was prevailing between 8°N and 12°N. During the study period, geographical differences existed in the peak values of upwelling favorable conditions considered for study. Analysis of the alongshore winds which are conducive for upwelling were observed to be curtailed towards the northern part of the study region between 2005 and 2010. Also, the strength of upwelling reduced during the strong ENSO years of 1997 and 2015. Linear regression based trend analysis of upwelling indices like Ekman transport, SST and chlorophyll along the coast, during the upwelling period, revealed slight increase in the strength towards the southern region while it decreased to the north during the study period.

VIIRS captures phytoplankton vertical migration in the NE Gulf of Mexico.

PubMed

Qi, Lin; Hu, Chuanmin; Barnes, Brian B; Lee, Zhongping

2017-06-01

In summer 2014, a toxic Karenia brevis bloom (red tide) occurred in the NE Gulf of Mexico, during which vertical migration of K. brevis has been observed from glider measurements. The current study shows that satellite observations from the Visible Infrared Imaging Radiometer Suite (VIIRS) can capture changes in surface reflectance and chlorophyll concentration occurring within 2h, which may be attributed this K. brevis vertical migration. The argument is supported by earlier glider measurements in the same bloom, by the dramatic changes in the VIIRS-derived surface chlorophyll, and by the consistency between the short-term reflectance changes and those reported earlier from field-measured K. brevis vertical migration. Estimates using the quasi-analytical algorithm also indicate significant increases in both total absorption coefficient and backscattering coefficient in two hours. The two observations in a day from a single polar-orbiting satellite sensor are thus shown to be able to infer phytoplankton vertical movement within a short timeframe, a phenomenon difficult to capture with other sensors as each sensor can provide at most one observation per day, and cross-sensor inconsistency may make interpretation of merged-sensor data difficult. These findings strongly support geostationary satellite missions to study short-term bloom dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

Upper Ocean Response to Hurricanes Katrina and Rita (2005) from Multi-sensor Satellites

NASA Astrophysics Data System (ADS)

Gierach, M. M.; Bulusu, S.

2006-12-01

Analysis of satellite observations and model simulations of the mixed layer provided an opportunity to assess the biological and physical effects of hurricanes Katrina and Rita (2005) in the Gulf of Mexico. Oceanic cyclonic circulation was intensified by the hurricanes' wind field, maximizing upwelling, surface cooling, and deepening the mixed layer. Two areas of maximum surface chlorophyll-a concentration and sea surface cooling were detected with peak intensities ranging from 2-3 mg m-3 and 4-6°C, along the tracks of Katrina and Rita. The temperature of the mixed layer cooled approximately 2°C and the depth of the mixed layer deepened by approximately 33-52 m. The forced deepening of the mixed layer injected nutrients into the euphotic zone, generating phytoplankton blooms 3-5 days after the passage of Katrina and Rita (2005).

Reflectance model for quantifying chlorophyll a in the presence of productivity degradation products

NASA Technical Reports Server (NTRS)

Carder, K. L.; Hawes, S. K.; Steward, R. G.; Baker, K. A.; Smith, R. C.; Mitchell, B. G.

1991-01-01

A reflectance model developed to estimate chlorophyll a concentrations in the presence of marine colored dissolved organic matter, pheopigments, detritus, and bacteria is presented. Nomograms and lookup tables are generated to describe the effects of different mixtures of chlorophyll a and these degradation products on the R(412):R(443) and R(443):R(565) remote-sensing reflectance or irradiance reflectance ratios. These are used to simulate the accuracy of potential ocean color satellite algorithms, assuming that atmospheric effects have been removed. For the California Current upwelling and offshore regions, with chlorophyll a not greater than 1.3 mg/cu m, the average error for chlorophyll a retrievals derived from irradiance reflectance data for degradation product-rich areas was reduced from +/-61 percent to +/-23 percent by application of an algorithm using two reflectance ratios rather than the commonly used algorithm applying a single reflectance ratio.

Nitrogen effects on proteins, chlorophylls and fatty acids during the growth of Arthrospira platensis.

PubMed

Ayachi, Samah; El Abed, Amor; Dhifi, Wissal; Marzouk, Brahim

2007-06-01

Spirulina platensis (=Arthrospira platensis) is a tunisian strain which has been isolated for the first time in Oued Essed (Sousse, Sidi Bou Ali). Biomass evolution, proteins, chlorophylls and fatty acids composition of this alga were monitored by varying nitrogen concentrations in the culture medium. Nitrogen stress was provoked by adding sodium nitrate (NaNO3) in the culture medium with concentrations varying from 0 to 5 g/l. Results obtained showed that nitrogen depletion increased total proteins and total chlorophylls. The addition of NaNO3 (5g/l) led to an increase of total fatty acids amounts and modify fatty acids composition. Optimal quantities of palmitic, gamma -linolenic and oleic acids were obtained with NaNO3 free-cultures. Thus, the tunisian strain has valuable biological substances, worthy to determine the optimal conditions for its propagation.

Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis1[OPEN

PubMed Central

Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E.; Chen, Ming; Zhou, Yongming; Yu, Bin

2015-01-01

Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. PMID:26048882

Chlorophyll Synthase under Epigenetic Surveillance Is Critical for Vitamin E Synthesis, and Altered Expression Affects Tocopherol Levels in Arabidopsis.

PubMed

Zhang, Chunyu; Zhang, Wei; Ren, Guodong; Li, Delin; Cahoon, Rebecca E; Chen, Ming; Zhou, Yongming; Yu, Bin; Cahoon, Edgar B

2015-08-01

Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene CHLOROPHYLL SYNTHASE (CHLSYN; At3g51820). Leaves from the homozygous chlysyn1-1 null mutant were nearly devoid of tocopherols, whereas seeds contained only approximately 25% of wild-type tocopherol levels. Leaves of RNA interference lines with partial suppression of CHLSYN displayed marked reductions in chlorophyll but up to a 2-fold increase in tocopherol concentrations. Cauliflower mosaic virus35S-mediated overexpression of CHLSYN unexpectedly caused a cosuppression phenotype at high frequencies accompanied by strongly reduced chlorophyll content and increased tocopherol levels. This phenotype and the associated detection of CHLSYN-derived small interfering RNAs were reversed with CHLSYN overexpression in rna-directed rna polymerase6 (rdr6), which is defective in RNA-dependent RNA polymerase6, a key enzyme in sense transgene-induced small interfering RNA production. CHLSYN overexpression in rdr6 had little effect on chlorophyll content but resulted in up to a 30% reduction in tocopherol levels in leaves. These findings show that altered CHLSYN expression impacts tocopherol levels and also, show a strong epigenetic surveillance of CHLSYN to control chlorophyll and tocopherol synthesis. © 2015 American Society of Plant Biologists. All Rights Reserved.

The chemical bonds effect of anthocyanin and chlorophyll dyes on TiO2 for dye-sensitized solar cell (DSSC)

NASA Astrophysics Data System (ADS)

Ahliha, A. H.; Nurosyid, F.; Supriyanto, A.; Kusumaningsih, T.

2017-11-01

Anthocyanin and chlorophyll dyes have been blended as the photosensitizer of Dye-Sensitized Solar Cell (DSSC). The results study showed the effect of chemical bond dyes on TiO2 and the efficiency of DSSC. Ratio blend of the anthocyanin and chlorophyll dyes are 1:1. The absorbance of dyes and TiO2 were characterized using UV-Vis Spectrophotometer. The chemical bonds contained in TiO2-dyes were characterized using FT-IR spectrophotometer. The efficiency of DSSC was calculated using I-V meter. The absorption spectra of chlorophyll: anthocyanin blend dye solutions and TiO2 films can increase after the dye adsorption. Absorbance characterization of anthocyanin and chlorophyll dye blend solutions showed three peaks at the wavelength of 412 nm; 535.5 nm; and 656.5 nm. Absorbance characterization of spinach before being blend with anthocyanin dyes solutions showed two peaks at the wavelength of 431 nm and 665.5 nm. The absorption spectra of TiO2 films can increase after the dyes adsorption at the wavelength of 400 nm. FT-IR spectra of TiO2 founded the functional groups C-Br, C=C, and O-H. The functional groups founded in anthocyanin: chlorophyll dye blended on the surface of TiO2 are C-Br, C-O, O-H, C-H, C=C, C=O, and O-H. The result showed that the greatest efficiency of 0.0544% at dye red cabbage-spinach. Adsorption blends of anthocyanin and chlorophyll dyes on the surface of TiO2 can be used as the photosensitizer for DSSC.

Water-quality conditions near the confluence of the Snake and Boise Rivers, Canyon County, Idaho

USGS Publications Warehouse

Wood, Molly S.; Etheridge, Alexandra

2011-01-01

Total Maximum Daily Loads (TMDLs) have been established under authority of the Federal Clean Water Act for the Snake River-Hells Canyon reach, on the border of Idaho and Oregon, to improve water quality and preserve beneficial uses such as public consumption, recreation, and aquatic habitat. The TMDL sets targets for seasonal average and annual maximum concentrations of chlorophyll-a at 14 and 30 micrograms per liter, respectively. To attain these conditions, the maximum total phosphorus concentration at the mouth of the Boise River in Idaho, a tributary to the Snake River, has been set at 0.07 milligrams per liter. However, interactions among chlorophyll-a, nutrients, and other key water-quality parameters that may affect beneficial uses in the Snake and Boise Rivers are unknown. In addition, contributions of nutrients and chlorophyll-a loads from the Boise River to the Snake River have not been fully characterized. To evaluate seasonal trends and relations among nutrients and other water-quality parameters in the Boise and Snake Rivers, a comprehensive monitoring program was conducted near their confluence in water years (WY) 2009 and 2010. The study also provided information on the relative contribution of nutrient and sediment loads from the Boise River to the Snake River, which has an effect on water-quality conditions in downstream reservoirs. State and site-specific water-quality standards, in addition to those that relate to the Snake River-Hells Canyon TMDL, have been established to protect beneficial uses in both rivers. Measured water-quality conditions in WY2009 and WY2010 exceeded these targets at one or more sites for the following constituents: water temperature, total phosphorus concentrations, total phosphorus loads, dissolved oxygen concentration, pH, and chlorophyll-a concentrations (WY2009 only). All measured total phosphorus concentrations in the Boise River near Parma exceeded the seasonal target of 0.07 milligram per liter. Data collected during the study show seasonal differences in all measured parameters. In particular, surprisingly high concentrations of chlorophyll-a were measured at all three main study sites in winter and early spring, likely due to changes in algal populations. Discharge conditions and dissolved orthophosphorus concentrations are key drivers for chlorophyll-a on a seasonal and annual basis on the Snake River. Discharge conditions and upstream periphyton growth are most likely the key drivers for chlorophyll-a in the Boise River. Phytoplankton growth is not limited or driven by nutrient availability in the Boise River. Lower discharges and minimal substrate disturbance in WY2010 in comparison with WY2009 may have caused prolonged and increased periphyton and macrophyte growth and a reduced amount of sloughed algae in suspension in the summer of WY2010. Chlorophyll-a measured in samples commonly is used as an indicator of sestonic algae biomass, but chlorophyll-a concentrations and fluorescence may not be the most appropriate surrogates for algae growth, eutrophication, and associated effects on beneficial uses. Assessment of the effects of algae growth on beneficial uses should evaluate not only sestonic algae, but also benthic algae and macrophytes. Alternatively, continuous monitoring of dissolved oxygen detects the influence of aquatic plant respiration for all types of algae and macrophytes and is likely a more direct measure of effects on beneficial uses such as aquatic habitat. Most measured water-quality parameters in the Snake River were statistically different upstream and downstream of the confluence with the Boise River. Higher concentrations and loads were measured at the downstream site (Snake River at Nyssa) than the upstream site (Snake River near Adrian) for total phosphorus, dissolved orthophosphorus, total nitrogen, dissolved nitrite and nitrate, suspended sediment, and turbidity. Higher dissolved oxygen concentrations and pH were measured at the upstream site (Snake River near Adrian) than the downstream site (Snake River at Nyssa). Contributions from the Boise River measured at Parma do not constitute all of the increase in nutrient and sediment loads in the Snake River between the upstream and downstream sites. Surrogate models were developed using a combination of continuously monitored variables to estimate concentrations of nutrients and suspended sediment when samples were not possible. The surrogate models explained from 66 to 95 percent of the variability in nutrient and suspended sediment concentrations, depending on the site and model. Although the surrogate models could not always represent event-based changes in modeled parameters, they generally were successful in representing seasonal and annual patterns. Over a longer period, the surrogate models could be a useful tool for measuring compliance with state and site-specific water-quality standards and TMDL targets, for representing daily and seasonal variability in constituents, and for assessing effects of phosphorus reduction measures within the watershed.

Seasonal And Regional Differentiation Of Bio-Optical Properties Within The North Polar Atlantic

NASA Technical Reports Server (NTRS)

Stramska, Malgorzata; Stramski, Dariusz; Kaczmarek, Slawomir; Allison, David B.; Schwarz, Jill

2005-01-01

Using data collected during spring and summer seasons in the north polar Atlantic we examined the variability of the spectral absorption, a(lambda), and backscattering, b(sub b)(lambda), coefficients of surface waters and its relation to phytoplankton pigment concentration and composition. For a given chlorophyll a concentration (TChla), the concentrations of photosynthetic carotenoids (PSC), photoprotective carotenoids (PPC), and total accessory pigments (AP) were consistently lower in spring than in summer. The chlorophyll-specific absorption coefficients of phytoplankton and total particulate matter were also lower in spring, which can be partly attributed to lower proportions of PPC, PSC, and AP in spring. The spring values of the green-to-blue band ratio of the absorption coefficient were higher than the summer ratios. The blue-to-green ratios of backscattering coefficient were also higher in spring. The higher b(sub b) values and lower blue-to-green b(sub b) ratios in summer were likely associated with higher concentrations of detrital particles in summer compared to spring. Because the product of the green-to-blue absorption ratio and the blue-to-green backscattering ratio is a proxy for the blue-to-green ratio of remote-sensing reflectance, we conclude that the performance of ocean color band-ratio algorithms for estimating pigments in the north polar Atlantic is significantly affected by seasonal shifts in the relationships between absorption and TChla as well as between backscattering and TChla. Intriguingly, however, fairly good estimate of the particulate beam attenuation coefficient at 660 nm (potential measure of total particulate matter or particulate organic carbon concentration) can be obtained by applying a single blue-to-green band-ratio algorithm for both spring and summer seasons.

Remote measurement of water color in coastal waters. [spectral radiance data used to obtain quantitative values for chlorophyll and turbidity

NASA Technical Reports Server (NTRS)

Weldon, J. W.

1973-01-01

An investigation was conducted to develop procedure to obtain quantitative values for chlorophyll and turbidity in coastal waters by observing the changes in spectral radiance of the backscattered spectrum. The technique under consideration consists of Examining Exotech model 20-D spectral radiometer data and determining which radiance ratios best correlated with chlorophyll and turbidity measurements as obtained from analyses of water samples and sechi visibility readings. Preliminary results indicate that there is a correlation between backscattered light and chlorophyll concentration and secchi visibility. The tests were conducted with the spectrometer mounted in a light aircraft over the Mississippi Sound at altitudes of 2.5K, 2.8K and 10K feet.

Dynamic responses of the benthic bacterial community at the Western English Channel observatory site L4 are driven by deposition of fresh phytodetritus

NASA Astrophysics Data System (ADS)

Tait, Karen; Airs, Ruth L.; Widdicombe, Claire E.; Tarran, Glen A.; Jones, Mark R.; Widdicombe, Stephen

2015-09-01

The impact of the seasonal deposition of phytoplankton and phytodetritus on surface sediment bacterial abundance and community composition was investigated at the Western English Channel site L4. Sediment and water samples were collected from January to September in 2012, increasing in frequency during periods of high water column phytoplankton abundance. Compared to the past two decades, the spring bloom in 2012 was both unusually long in duration and contained higher than average biomass. Within spring months, the phytoplankton bloom was well mixed through the water column and showed accumulations near the sea bed, as evidenced by flow cytometry measurements of nanoeukaryotes, water column chlorophyll a and the appearance of pelagic phytoplankton at the sediment. Measurements of chlorophyll and chlorophyll degradation products indicated phytoplankton material was heavily degraded after it reached the sediment surface: the nature of the chlorophyll degradation products (predominantly pheophorbide, pyropheophorbide and hydroxychlorophyllone) was indicative of grazing activity. The abundance of bacterial 16S rRNA genes g-1 sediment (used as a proxy for bacterial biomass) increased markedly with the onset of the phytoplankton bloom, and correlated with measurements of chlorophyll at the surface sediment. Together, this suggests that bacteria may have responded to nutrients released via grazing activity. In depth sequencing of the 16S rRNA genes indicated that the composition of the bacterial community shifted rapidly through-out the prolonged spring bloom period. This was primarily due to an increase in the relative sequence abundance of Flavobacteria.

Impact of culture conditions on the chlorophyll content of microalgae for biotechnological applications.

PubMed

da Silva Ferreira, Veronica; Sant'Anna, Celso

2017-01-01

Chlorophyll is a commercially important natural green pigment responsible for the absorption of light energy and its conversion into chemical energy via photosynthesis in plants and algae. This bioactive compound is widely used in the food, cosmetic, and pharmaceutical industries. Chlorophyll has been consumed for health benefits as a nutraceutical agent with antioxidant, anti-inflammatory, antimutagenic, and antimicrobial properties. Microalgae are photosynthesizing microorganisms which can be extracted for several high-value bioproducts in the biotechnology industry. These microorganisms are highly efficient at adapting to physicochemical variations in the local environment. This allows optimization of culture conditions for inducing microalgal growth and biomass production as well as for changing their biochemical composition. The modulation of microalgal culture under controlled conditions has been proposed to maximize chlorophyll accumulation. Strategies reported in the literature to promote the chlorophyll content in microalgae include variation in light intensity, culture agitation, and changes in temperature and nutrient availability. These factors affect chlorophyll concentration in a species-specific manner; therefore, optimization of culture conditions has become an essential requirement. This paper provides an overview of the current knowledge on the effects of key environmental factors on microalgal chlorophyll accumulation, focusing on small-scale laboratory experiments.

The Use of Chlorophyll Fluorescence Lifetime to Assess Phytoplankton Physiology within a River-Dominated Environment

NASA Technical Reports Server (NTRS)

Hall, Callie M.; Miller, Richard L.; Redalje, Donald G.; Fernandez, Salvador M.

2002-01-01

Chlorophyll a fluorescence lifetime was measured for phytoplankton populations inhabiting the three physical zones surrounding the Mississippi River's terminus in the Gulf of Mexico. Observations of river discharge volume, nitrate + nitrite, silicate, phosphate, PAR (Photosynthetically Active Radiation) diffuse attenuation within the water column, salinity, temperature, SPM, and chl a concentration were used to characterize the distribution of chl fluorescence lifetime within a given region within restricted periods of time. 33 stations extending from the Mississippi River plume to the shelf break of the Louisiana coast were surveyed for analysis of chlorophyll fluorescence lifetime during two cruises conducted March 31 - April 6, 2000, and October 24 - November 1, 2000. At each station, two to three depths were chosen for fluorescence lifetime measurement to represent the vertical characteristics of the water column. Where possible, samples were taken from just below the surface and from just above and below the pycnocline. All samples collected were within the 1% light level of the water column (the euphotic zone). Upon collection, samples were transferred to amber Nalgene bottles and left in the dark for at least 15 minutes to reduce the effects of non-photochemical quenching and to insure that photosynthetic reaction centers were open. Before measurements within the phase fluorometer were begun, the instrument was allowed to warm up for no less than one hour.

Seasonal variations of leaf and canopy properties tracked by ground-based NDVI imagery in a temperate forest

DOE PAGES

Yang, Hualei; Yang, Xi; Heskel, Mary; ...

2017-04-28

Changes in plant phenology affect the carbon flux of terrestrial forest ecosystems due to the link between the growing season length and vegetation productivity. Digital camera imagery, which can be acquired frequently, has been used to monitor seasonal and annual changes in forest canopy phenology and track critical phenological events. However, quantitative assessment of the structural and biochemical controls of the phenological patterns in camera images has rarely been done. In this study, we used an NDVI (Normalized Difference Vegetation Index) camera to monitor daily variations of vegetation reflectance at visible and near-infrared (NIR) bands with high spatial and temporalmore » resolutions, and found that the infrared camera based NDVI (camera-NDVI) agreed well with the leaf expansion process that was measured by independent manual observations at Harvard Forest, Massachusetts, USA. We also measured the seasonality of canopy structural (leaf area index, LAI) and biochemical properties (leaf chlorophyll and nitrogen content). Here we found significant linear relationships between camera-NDVI and leaf chlorophyll concentration, and between camera-NDVI and leaf nitrogen content, though weaker relationships between camera-NDVI and LAI. Therefore, we recommend ground-based camera-NDVI as a powerful tool for long-term, near surface observations to monitor canopy development and to estimate leaf chlorophyll, nitrogen status, and LAI.« less

Deriving depths of deep chlorophyll maximum and water inherent optical properties: A regional model

NASA Astrophysics Data System (ADS)

Xiu, Peng; Liu, Yuguang; Li, Gang; Xu, Qing; Zong, Haibo; Rong, Zengrui; Yin, Xiaobin; Chai, Fei

2009-10-01

The Bohai Sea is a semi-enclosed inland sea with case-2 waters near the coast. A comprehensive set of optical data was collected during three cruises in June, August, and September 2005 in the Bohai Sea. The vertical profile measurements, such as chlorophyll concentration, water turbidity, downwelling irradiance, and diffuse attenuation coefficient, showed that the Bohai Sea was vertically stratified with a relative clear upper layer superimposed on a turbid lower layer. The upper layer was found to correspond to the euphotic zone and the deep chlorophyll maximum (DCM) occurs at the base of this layer. By tuning a semi-analytical model (Lee et al., 1998, 1999) for the Bohai Sea, we developed a method to derive water inherent optical properties and the depth of DCM from above-surface measurements. Assuming a 'fake' bottom in the stratified water, this new method retrieves the 'fake' bottom depth, which is highly correlated with the DCM depth. The average relative error between derived and measured values is 33.9% for phytoplankton absorption at 440 nm, 25.6% for colored detrital matter (detritus plus gelbstoff) absorption at 440 nm, and 24.2% for the DCM depth. This modified method can retrieve water inherent optical properties and monitor the depth of DCM in the Bohai Sea, and the method is also applicable to other stratified waters.

Seasonal variations of leaf and canopy properties tracked by ground-based NDVI imagery in a temperate forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Hualei; Yang, Xi; Heskel, Mary

Changes in plant phenology affect the carbon flux of terrestrial forest ecosystems due to the link between the growing season length and vegetation productivity. Digital camera imagery, which can be acquired frequently, has been used to monitor seasonal and annual changes in forest canopy phenology and track critical phenological events. However, quantitative assessment of the structural and biochemical controls of the phenological patterns in camera images has rarely been done. In this study, we used an NDVI (Normalized Difference Vegetation Index) camera to monitor daily variations of vegetation reflectance at visible and near-infrared (NIR) bands with high spatial and temporalmore » resolutions, and found that the infrared camera based NDVI (camera-NDVI) agreed well with the leaf expansion process that was measured by independent manual observations at Harvard Forest, Massachusetts, USA. We also measured the seasonality of canopy structural (leaf area index, LAI) and biochemical properties (leaf chlorophyll and nitrogen content). Here we found significant linear relationships between camera-NDVI and leaf chlorophyll concentration, and between camera-NDVI and leaf nitrogen content, though weaker relationships between camera-NDVI and LAI. Therefore, we recommend ground-based camera-NDVI as a powerful tool for long-term, near surface observations to monitor canopy development and to estimate leaf chlorophyll, nitrogen status, and LAI.« less

Identification of chlorophyll ( with application of IRS-P4 OCM data and Geographical Information System - a case study of part of Bay of Bengal, India

NASA Astrophysics Data System (ADS)

Pavan Dayaker, T.

2002-05-01

As 60 - 70 % of the world's population live within 20 - 30 km of the coastline, coastal zone management and optimisation of ocean resources have grown in of importance. The study of the ocean encompasses its physical chemical, biological properties and its interaction with land and biological productivity. Mapping of coastal zone gives us insight about how to conserve its eco-balance and implement effective coastal zone management. Effective Coastal Zone Management will need accurate and comprehensive scientific data, on which decisions can be based. In the present study Ocean Color Monitor ( OCM ) data is used for identification of chlorophyll, which inturn indicates the presence of phytoplankton, which is the primary producer in the food chain, and also to fish . The study area is part of Bay of Bengal Sea near the coastal region of Andhra Pradesh, India. Remote sensing in optical region is found useful in understanding the spatial distribution of ocean water constituents, in which phytoplankton pigment which impart a green colour to the sea water, has a definite response in the visible region, which enables plant material to be distinguished from the other suspended matter. Normalised Differential Vegetative Index ( NDVI ), which is mainly used on land applications for the identification of vegetation based on chlorophyll absorption, is used on water surface in the present study. The positive value of NDVI is an indication of the presence of pigment concentration / chlorophyll / phytoplankton / fish. The successful launch of the IRS - P4 satellite which provides us a challenging opportunity to study ocean resources and its characteristics and see how best we can benefit, over a period of time, in several areas of human survival specifically related to food security on a sustained basis. This study is first of its kind in utilising the latest technology to explore the marine resources for mapping the fishing zones and the results, clearly indicate that NDVI can be utilised as an indicator for the presence of phytoplankton on water surface.

Decadal biogeochemical history of the south east Levantine basin: Simulations of the river Nile regimes

NASA Astrophysics Data System (ADS)

Suari, Yair; Brenner, Steve

2015-08-01

The south eastern Mediterranean is characterized by antiestuarine circulation which leads to extreme oligotrophic conditions. The Nile river that used to transport fresh water and nutrients into the basin was dammed in 1964 which led to a drastic reduction of fresh water fluxes, and later, changes in Egyptian agriculture and diet led to increased nutrient fluxes. In this paper we present the results of simulations with a biogeochemical model of the south eastern Mediterranean. Four experiments were conducted: (1) present day without riverine inputs; (2) Nile before damming (pre-1964); (3) post-damming 1995 Nile; and (4) fresh water and nutrient discharges of Israeli coastal streams. The present day input simulation (control run) successfully reproduced measured nutrient concentrations, with the exception of simulated chlorophyll concentrations which were slightly higher than observed. The pre-1964 Nile simulation showed a salinity reduction of 2 psu near the Egyptian coast and 0.5 psu along the Israeli coast, as well as elevated chlorophyll a concentrations mostly east of the Nile delta and north to Cyprus. The spring bloom extended from its present peak during February-March to a peak during February-May. The 1995 Nile simulation showed increased chlorophyll a concentrations close to the Egyptian coast. The Israeli coastal stream simulation showed that the effect of the Israeli coastal stream winter flow on chlorophyll converged to control concentrations within about one month, demonstrating the stability and sensitivity of the model to external forcing. The results of this study demonstrate the significance of fresh water fluxes in maintaining marine productivity, which may have large scale effects on the marine ecosystem.

Fronts and eddies: Engines for biogeochemical variability of the Central Red Sea during winter-spring periods

NASA Astrophysics Data System (ADS)

Zarokanellos, Nikolaos; Jones, Burton

2017-04-01

The central Red Sea (CRS) has been shown to be characterized by significant eddy activity throughout the year. In winter, weakened stratification may lead to enhanced vertical exchange contributing to physical and biogeochemical processes. In winter 2014-2015 we began an extended glider time series to monitor a region in the northern CRS where eddy activity is significant. Remote sensing and glider observations that include CTD, oxygen, CDOM and chlorophyll fluorescence, and multi-wavelength optical backscatter, have been used to characterize the effects of winter mixing and eddy activity in this region. During winter, deep mixing driven by surface cooling and strong winds combined with eddy features, can supply nutrients into the upper layer dramatically modifies the environment from its typically stratified conditions. These mixing events disperse the phytoplankton from the deep chlorophyll maximum throughout the upper mixed layer, and increase the chlorophyll signature detected by ocean color imagery. In addition to the mixing, cyclonic eddies in the region can enhance the vertical displacement of deeper, nutrient containing water toward the euphotic zone contributing to increased chlorophyll concentration and biological productivity. Remote sensing analyses indicate that these eddies also contribute to significant horizontal dispersion including the exchange between the open sea and coastal coral reef ecosystems. During the winter mixing periods, diel fluctuations in phytoplankton biomass have been observed indicative of solar driven plankton dynamics. The biogeochemical response to the subsurface physical processes provides a sensitive indicator to the processes that result from the mixing and eddy dynamics - processes that are not necessarily detectable via remote sensing. In order to understand the seasonal responses, but also the interannual influences on these processes, sustained in situ autonomous platform measurements are essential.

Satellite remote sensing for modeling and monitoring of water quality in the Great Lakes

NASA Astrophysics Data System (ADS)

Coffield, S. R.; Crosson, W. L.; Al-Hamdan, M. Z.; Barik, M. G.

2017-12-01

Consistent and accurate monitoring of the Great Lakes is critical for protecting the freshwater ecosystems, quantifying the impacts of climate change, understanding harmful algal blooms, and safeguarding public health for the millions who rely on the Lakes for drinking water. While ground-based monitoring is often hampered by limited sampling resolution, satellite data provide surface reflectance measurements at much more complete spatial and temporal scales. In this study, we implemented NASA data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to build robust water quality models. We developed and validated models for chlorophyll-a, nitrogen, phosphorus, and turbidity based on combinations of the six MODIS Ocean Color bands (412, 443, 488, 531, 547, and 667nm) for 2003-2016. Second, we applied these models to quantify trends in water quality through time and in relation to changing land cover, runoff, and climate for six selected coastal areas in Lakes Michigan and Erie. We found strongest models for chlorophyll-a in Lake Huron (R2 = 0.75), nitrogen in Lake Ontario (R2=0.66), phosphorus in Lake Erie (R2=0.60), and turbidity in Lake Erie (R2=0.86). These offer improvements over previous efforts to model chlorophyll-a while adding nitrogen, phosphorus, and turbidity. Mapped water quality parameters showed high spatial variability, with nitrogen concentrated largely in Superior and coastal Michigan and high turbidity, phosphorus, and chlorophyll near urban and agricultural areas of Erie. Temporal analysis also showed concurrence of high runoff or precipitation and nitrogen in Lake Michigan offshore of wetlands, suggesting that water quality in these areas is sensitive to changes in climate.

Seasonality of North Atlantic phytoplankton from space: impact of environmental forcing on a changing phenology (1998-2012).

PubMed

González Taboada, Fernando; Anadón, Ricardo

2014-03-01

Seasonal pulses of phytoplankton drive seasonal cycles of carbon fixation and particle sedimentation, and might condition recruitment success in many exploited species. Taking advantage of long-term series of remotely sensed chlorophyll a (1998-2012), we analyzed changes in phytoplankton seasonality in the North Atlantic Ocean. Phytoplankton phenology was analyzed based on a probabilistic characterization of bloom incidence. This approach allowed us to detect changes in the prevalence of different seasonal cycles and, at the same time, to estimate bloom timing and magnitude taking into account uncertainty in bloom detection. Deviations between different sensors stressed the importance of a prolonged overlap between successive missions to ensure a correct assessment of phenological changes, as well as the advantage of semi-analytical chlorophyll algorithms over empirical ones to reduce biases. Earlier and more intense blooms were detected in the subpolar Atlantic, while advanced blooms of less magnitude were common in the Subtropical gyre. In the temperate North Atlantic, spring blooms advanced their timing and decreased in magnitude, whereas fall blooms delayed and increased their intensity. At the same time, the prevalence of locations with a single autumn/winter bloom or with a bimodal seasonal cycle increased, in consonance with a poleward expansion of subtropical conditions. Changes in bloom timing and magnitude presented a clear signature of environmental factors, especially wind forcing, although changes on incident photosynthetically active radiation and sea surface temperature were also important depending on latitude. Trends in bloom magnitude matched changes in mean chlorophyll a during the study period, suggesting that seasonal peaks drive long-term trends in chlorophyll a concentration. Our results link changes in North Atlantic climate with recent trends in the phenology of phytoplankton, suggesting an intensification of these impacts in the near future. © 2013 John Wiley & Sons Ltd.

A 3-D ecosystem model in the Pacific Ocean and its simulations

NASA Astrophysics Data System (ADS)

Xu, Y.; Ba, Q.

2011-12-01

A simple 3-D ecosystem model with nutrient, phytoplankton, zooplankton and detritus is coupled into the basinwide ocean general circulation (OGCM) of the Pacific Ocean that has been examined by the passive tracer such as tritium. The model was integrated for 500 years under the forcing of climatological monthly mean fields. The model generates similar distribution patterns of ecosystem variables to the estimates based on satellite-derived chlorophyll maps by vertically generalized production model with low water-column NPP values in the subtropical region and high values in the subarctic region and equatorial upwelling region. But the area and strength of oligotrophic gyre is much larger than that indicated in the observations. Compared with the observations, seasonal variations of surface chlorophyll concentrations and top 200-m average zooplankton biomass in the mid-high latitude regions are well simulated in the model. Because of the restoring term near the northern boundary used in the model, a false phytoplankton bloom can occur nearby 50N during winter time. An unrealistic maximum value in the vertical profile of chlorophyll near ocean weather station Papa is generated by our model. In terms of modification of model structure and sensitivity test of the associated parameters, the simulated results can be well improved. Although the division of nutrient into nitrate and ammonium and inclusion of DON in the model can alleviate the low-NPP problem in the subtropical region, modification of the sinking rate and decomposition rate of detritus in the model can be more effective. Introduction of the influence of mixed layer on the ecosystem process and modification of restraint of nutrients near the northern boundary can overcome the shortcomings of simulation of both spring bloom near 50N and vertical profile of chlorophyll at Papa to some extent.

Monsoon-induced changes in the size-fractionated phytoplankton biomass and production rate in the estuarine and coastal waters of southwest coast of India.

PubMed

Madhu, N V; Jyothibabu, R; Balachandran, K K

2010-07-01

Changes in the autotrophic pico- (0.2-2 microm), nano- (2-20 microm), and microplankton (>20 microm) biomass (chlorophyll a) and primary production were measured in the estuarine and coastal waters off Cochin, southwest coast of India during the onset and establishment of a monsoon. During this period, the estuary was dominated by nutrient-rich freshwater, whereas the coastal waters were characterized with higher salinity values (>30 psu) and less nutrients. The average surface chlorophyll a concentrations and primary production rates were higher in the estuary (average 13.7 mg m(-3) and 432 mgC m(-3) day(-1)) as compared to the coastal waters (5.3 mg m(-3) and 224 mgC m(-3) day(-1)). The nanoplankton community formed the major fraction of chlorophyll a and primary production, both in the estuary (average 85 +/- SD 8.3% and 81.2 +/- SD 3.2%) and the coastal waters (average 73.2 +/- SD 17.2% and 81.9 +/- 15.7%). Nanoplankton had the maximum photosynthetic efficiency in the coastal waters (average 4.8 +/- SD 3.9 mgC mgChl a m(-3) h(-1)), whereas in the estuary, the microplankton had higher photosynthetic efficiency (average 7.4 +/- 7 mgC mgChl a m(-3) h(-1)). The heavy cloud cover and increased water column turbidity not only limit the growth of large-sized phytoplankton in the Cochin estuary and coastal waters but also support the proliferation of nanoplankton community during the monsoon season, even though large variation in nanoplankton chlorophyll a and production exists between these two areas.

Measurement of Chlorophyll Loss Due to Phytoremediation of Ag Nanoparticles in the First-Year Laboratory

ERIC Educational Resources Information Center

Winkelmann, Kurt; Bernas, Leonard; Swiger, Brendan; Brown, Shannon

2017-01-01

A two-week experiment is presented in which students can observe the impact of nanoparticles on the concentration of chlorophyll in plants. First-year students in an introductory nanotechnology laboratory course and a general chemistry laboratory course synthesized silver nanoparticles and then exposed stalks of "Egeria densa" ("E.…