Inverse modeling of primary production

Dva tipa implementacije 14C metode za mjerenje asimilacije ugljika pri fotosintezi se razlikuju s obzirom na svjetlosne uvjete pri kojima se vrše eksperimenti: in vitro i in situ. In vitro inkubacije se vrše u laboratoriju pod kontroliranim svjetlosnim uvjetima, dok se in situ inkubacije vrše u moru pod prirodnim svjetlosnim uvjetima. Ovisnost primarne proizvodnje o svjetlosti se matematički opisuje funkcijama svjetlosnog zasićenja čiji parametri određuju brzinu asimilacije ugljika pri fotosintezi. Vrijednosti fotosintetskih parametara se odreduju na temelju rezultata in vitro mjerenja i poslije se koriste u modelima primarne proizvodnje. U ovom radu je razvijen inverzni model koji koristi in situ mjerenja za procjenu vrijednosti fotosintetskih parametara. Pritom upotrebljava optimizacijski algoritam koji tretira fotosintetske parametre modela proizvodnje kao varijable optimizacije i nalazi optimalne vrijednosti parametara za koje model najmanje odstupa od in situ mjerenja. Inverzni model koristi model primarne proizvodnje formuliran pomoću dva različita formalizma, od prije poznatog analitičkog formalizma i ovdje razvijenog matričnog formalizma. Korištenjem analitičkog formalizma, uz pretpostavku idealiziranih svjetlosnih uvjeta, nađeno je analitičko rješenje za profil proizvodnje i analitičko rješenje za proizvodnju vodenog stupca s biomasom ovisnom o dubini. Inverzni model je testiran na 194 in situ prola primarne proizvodnje s Hawaii Ocean Time-series i procijenjene su vrijednosti parametara za različite funkcije svjetlosnog zasićenja. Korištenjem optimalnih vrijednosti parametara modeli su opisali preko 95% varijabilnosti izmjerene proizvodnje po dubini i preko 95% varijabilnosti izmjerene proizvodnje vodenog stupca. Kao rezultat ovog rada, inverzni model je postao novi alat za procjenu vrijednosti fotosintetskih parametara iz in situ prola primarne proizvodnje.Two types of implementation of the 14C method for measuring carbon assimilation in photosynthesis are differentiated with respect to light conditions under which the experiments are performed: in vitro and in situ. In vitro incubations are performed in the laboratory under controlled light conditions, whereas in situ incubations are performed at sea under natural light conditions. The dependence of primary production on light is mathematically described with light saturation functions, whose parameters determine the rate of carbon assimilation in photosynthesis. The values of photosynthesis parameters are determined based on the results of in vitro measurements and are afterwards used in models of primary production. In this work an inverse model is developed which uses in situ measurements to estimate the values of the photosynthesis parameters. It employs an optimization algorithm which treats the photosynthesis parameters of the production model as optimization variables and estimates optimal parameter values for which the model deviates the least from the in situ measurements. The inverse model uses the primary production model formulated with two different formalisms, an already established analytical formalism and here developed matrix formalism. Using the analytical formalism, under the assumption of idealized light conditions, an analytical solution for the production prole and the analytical solution for water column production with depth dependent biomass were derived. The inverse model was tested on 194 in situ primary production proles from the Hawaii Ocean Time-series and the parameters of dierent light saturation functions were estimated. When using optimal parameter values the models explained over 95% of variability in measured production at depth and over 95% of variability in the measured water column production. As a result of this work, the inverse model became a new tool for estimating the values of the photosynthesis parameters from in situ primary production profiles

Inverse modeling of primary production

Dva tipa implementacije 14C metode za mjerenje asimilacije ugljika pri fotosintezi se razlikuju s obzirom na svjetlosne uvjete pri kojima se vrše eksperimenti: in vitro i in situ. In vitro inkubacije se vrše u laboratoriju pod kontroliranim svjetlosnim uvjetima, dok se in situ inkubacije vrše u moru pod prirodnim svjetlosnim uvjetima. Ovisnost primarne proizvodnje o svjetlosti se matematički opisuje funkcijama svjetlosnog zasićenja čiji parametri određuju brzinu asimilacije ugljika pri fotosintezi. Vrijednosti fotosintetskih parametara se odreduju na temelju rezultata in vitro mjerenja i poslije se koriste u modelima primarne proizvodnje. U ovom radu je razvijen inverzni model koji koristi in situ mjerenja za procjenu vrijednosti fotosintetskih parametara. Pritom upotrebljava optimizacijski algoritam koji tretira fotosintetske parametre modela proizvodnje kao varijable optimizacije i nalazi optimalne vrijednosti parametara za koje model najmanje odstupa od in situ mjerenja. Inverzni model koristi model primarne proizvodnje formuliran pomoću dva različita formalizma, od prije poznatog analitičkog formalizma i ovdje razvijenog matričnog formalizma. Korištenjem analitičkog formalizma, uz pretpostavku idealiziranih svjetlosnih uvjeta, nađeno je analitičko rješenje za profil proizvodnje i analitičko rješenje za proizvodnju vodenog stupca s biomasom ovisnom o dubini. Inverzni model je testiran na 194 in situ prola primarne proizvodnje s Hawaii Ocean Time-series i procijenjene su vrijednosti parametara za različite funkcije svjetlosnog zasićenja. Korištenjem optimalnih vrijednosti parametara modeli su opisali preko 95% varijabilnosti izmjerene proizvodnje po dubini i preko 95% varijabilnosti izmjerene proizvodnje vodenog stupca. Kao rezultat ovog rada, inverzni model je postao novi alat za procjenu vrijednosti fotosintetskih parametara iz in situ prola primarne proizvodnje.Two types of implementation of the 14C method for measuring carbon assimilation in photosynthesis are differentiated with respect to light conditions under which the experiments are performed: in vitro and in situ. In vitro incubations are performed in the laboratory under controlled light conditions, whereas in situ incubations are performed at sea under natural light conditions. The dependence of primary production on light is mathematically described with light saturation functions, whose parameters determine the rate of carbon assimilation in photosynthesis. The values of photosynthesis parameters are determined based on the results of in vitro measurements and are afterwards used in models of primary production. In this work an inverse model is developed which uses in situ measurements to estimate the values of the photosynthesis parameters. It employs an optimization algorithm which treats the photosynthesis parameters of the production model as optimization variables and estimates optimal parameter values for which the model deviates the least from the in situ measurements. The inverse model uses the primary production model formulated with two different formalisms, an already established analytical formalism and here developed matrix formalism. Using the analytical formalism, under the assumption of idealized light conditions, an analytical solution for the production prole and the analytical solution for water column production with depth dependent biomass were derived. The inverse model was tested on 194 in situ primary production proles from the Hawaii Ocean Time-series and the parameters of dierent light saturation functions were estimated. When using optimal parameter values the models explained over 95% of variability in measured production at depth and over 95% of variability in the measured water column production. As a result of this work, the inverse model became a new tool for estimating the values of the photosynthesis parameters from in situ primary production profiles

Inverse modeling of primary production

Dva tipa implementacije 14C metode za mjerenje asimilacije ugljika pri fotosintezi se razlikuju s obzirom na svjetlosne uvjete pri kojima se vrše eksperimenti: in vitro i in situ. In vitro inkubacije se vrše u laboratoriju pod kontroliranim svjetlosnim uvjetima, dok se in situ inkubacije vrše u moru pod prirodnim svjetlosnim uvjetima. Ovisnost primarne proizvodnje o svjetlosti se matematički opisuje funkcijama svjetlosnog zasićenja čiji parametri određuju brzinu asimilacije ugljika pri fotosintezi. Vrijednosti fotosintetskih parametara se odreduju na temelju rezultata in vitro mjerenja i poslije se koriste u modelima primarne proizvodnje. U ovom radu je razvijen inverzni model koji koristi in situ mjerenja za procjenu vrijednosti fotosintetskih parametara. Pritom upotrebljava optimizacijski algoritam koji tretira fotosintetske parametre modela proizvodnje kao varijable optimizacije i nalazi optimalne vrijednosti parametara za koje model najmanje odstupa od in situ mjerenja. Inverzni model koristi model primarne proizvodnje formuliran pomoću dva različita formalizma, od prije poznatog analitičkog formalizma i ovdje razvijenog matričnog formalizma. Korištenjem analitičkog formalizma, uz pretpostavku idealiziranih svjetlosnih uvjeta, nađeno je analitičko rješenje za profil proizvodnje i analitičko rješenje za proizvodnju vodenog stupca s biomasom ovisnom o dubini. Inverzni model je testiran na 194 in situ prola primarne proizvodnje s Hawaii Ocean Time-series i procijenjene su vrijednosti parametara za različite funkcije svjetlosnog zasićenja. Korištenjem optimalnih vrijednosti parametara modeli su opisali preko 95% varijabilnosti izmjerene proizvodnje po dubini i preko 95% varijabilnosti izmjerene proizvodnje vodenog stupca. Kao rezultat ovog rada, inverzni model je postao novi alat za procjenu vrijednosti fotosintetskih parametara iz in situ prola primarne proizvodnje.Two types of implementation of the 14C method for measuring carbon assimilation in photosynthesis are differentiated with respect to light conditions under which the experiments are performed: in vitro and in situ. In vitro incubations are performed in the laboratory under controlled light conditions, whereas in situ incubations are performed at sea under natural light conditions. The dependence of primary production on light is mathematically described with light saturation functions, whose parameters determine the rate of carbon assimilation in photosynthesis. The values of photosynthesis parameters are determined based on the results of in vitro measurements and are afterwards used in models of primary production. In this work an inverse model is developed which uses in situ measurements to estimate the values of the photosynthesis parameters. It employs an optimization algorithm which treats the photosynthesis parameters of the production model as optimization variables and estimates optimal parameter values for which the model deviates the least from the in situ measurements. The inverse model uses the primary production model formulated with two different formalisms, an already established analytical formalism and here developed matrix formalism. Using the analytical formalism, under the assumption of idealized light conditions, an analytical solution for the production prole and the analytical solution for water column production with depth dependent biomass were derived. The inverse model was tested on 194 in situ primary production proles from the Hawaii Ocean Time-series and the parameters of dierent light saturation functions were estimated. When using optimal parameter values the models explained over 95% of variability in measured production at depth and over 95% of variability in the measured water column production. As a result of this work, the inverse model became a new tool for estimating the values of the photosynthesis parameters from in situ primary production profiles

Oil spills distribution in the Middle and Southern Adriatic Sea as a result of intensive ship traffic

Detekcija uljnih mrlja sintetičkim satelitskim radarom (SAR) provjerena je i najčešće korištena operativna tehnika, koja je pokazala kako je Sredozemno more često zagađeno uljem i sličnim proizvodima. Zahvaljujući nekolicini projekata Envisat i Radarsat-1 SAR slike su za razdoblje 2003-2011 bile dostupne za analizu. Analizirano je oko 300 SAR slika srednjeg i južnog Jadrana, kako bi se otkrile pojave naftnih mrlja i druge pojave koje imaju sličan signal na satelitskim snimcima. Otkrivena su mnoga izlijevanja nafte u Jadranu, čije su površine bile između 0,1 km2 i 108 km2. Većina izlijevanja je smještena uz glavne brodske rute, osobito u brodskom koridoru duž osi Jadranskog mora. To su vjerojatno ulja namjerno izlivena s brodova tijekom prijevoza ili ribolovnih operacija, a najčešći slučajevi izlijevanja su pranje brodskih spremnika ili nedozvoljena pražnjenja tankova.Oil slick detection by synthetic aperture radars (SAR) is a proven and commonly used operational technique, which showed that the seas of the Mediterranean are often polluted by oil and oily products. For the period 2003-2011, the Envisat and Radarsat-1 SAR images were available for analysis, thanks to the several projects. About 300 SAR images have been analysed over the Middle and Southern Adriatic Sea, in order to detect marine oil spills and other phenomena causing similar signatures. Analysing many oil spills detected in the Adriatic Sea, their sizes were determined between 0.1 km2 and 108 km2. Most of the spills were located along the main shipping routes, especially in the ship corridor along the Adriatic Sea axis. They were, most probably deliberate slicks released from ships during transportation or fishing operations, while suspected source of the largest spills is tank washing or illegal discharges

Extraction of Photosynthesis Parameters from Time Series Measurements of In Situ Production: Bermuda Atlantic Time-Series Study

Computing the vertical structure of primary production in ocean ecosystem models requires information about the vertical distribution of available light, chlorophyll concentration and photosynthesis response parameters. Conversely, given information on vertical structure of chlorophyll and light, we can extract photosynthesis parameters from vertical profiles of primary production measured at sea, as we illustrate here for the Bermuda Atlantic Time-Series Study. The procedure is based on a model of the production profile, which itself depends on the underwater light field. To model the light field, attenuation coefficients were estimated from measured optical profiles using a simple model of exponential decay of photosynthetically-available irradiance with depth, which accounted for 97% of the variance in the measured optical data. With the underwater light climate known, an analytical solution for the production profile was employed to recover photosynthesis parameters by minimizing the residual model error. The recovered parameters were used to model normalized production profiles and normalized watercolumn production. The model explained 95% of the variance in the measured normalized production at depth and 97% of the variance in measured normalized watercolumn production. A shifted Gaussian function was used to model biomass profiles and accounted for 93% of the variance in measured biomass at depth. An analytical solution for watercolumn production with the shifted Gaussian biomass was also tested. With the recovered photosynthesis parameters, maximum instantaneous growth rates were estimated by using a literature value for the carbon-to-chlorophyll ratio in this region of the Atlantic. An exact relationship between the maximum instantaneous growth rate and the daily growth rate in the ocean was derived. It was shown that calculating the growth rate by dividing the production by the carbon-to-chlorophyll ratio is equivalent to calculating it from the ratio of the final to the initial biomass, even when production is time dependent. Finally, the seasonal cycle of the recovered assimilation number at the Bermuda Station was constructed and analysed. The presented approach enables the estimation of photosynthesis parameters and growth rates from measured production profiles with only a few model assumptions, and increases the utility of in situ primary production measurements. The retrieved parameters have direct applications in satellite-based estimates of primary production from ocean-colour data, of which we give an example

Extended Formulations and Analytic Solutions for Watercolumn Production Integrals

The effect of biomass dynamics on the estimation of watercolumn primary production is analyzed, by coupling a primary production model to a simple growth equation for phytoplankton. The production model is formulated with depth- and time-resolved biomass, and placed in the context of earlier models, with emphasis on the canonical solution for watercolumn production. A relation between the canonical solution and the general solution for the case of an arbitrary depth-dependent biomass profile was derived, together with an analytical solution for watercolumn production in case of a depth dependent biomass profile described with the shifted Gaussian function. The analysis was further extended to the case of a time-dependent, mixed-layer biomass, and two additional analytical solutions to this problem were derived, the first in case of increasing mixed-layer biomass and the second in case of declining biomass. The solutions were tested with Hawaii Ocean Time-series data. The canonical solution for mixed-layer production has proven to be a good model for this data set. The shifted Gaussian function was demonstrated to be an accurate model for the measured biomass profiles and the shifted Gaussian parameters extracted from the measured profiles were further used in the analytical solution for watercolumn production and results compared with data. The influence of time-dependent biomass on mixed-layer production was studied through analytical solutions. Re-examining the Critical Depth Hypothesis we derived an expression for the daily increase in mixed-layer biomass. Finally, the work was placed in a remote sensing context and the time-dependent model for biomass related to the remotely sensed-biomass

Could an Early Treatment with GA and BA Impact Prolonged Cold Storage and Shelf Life of Apricot?

Application of plant growth regulators (PGRs) in apricot orchards is a common practice with a goal of improving yield and/or quality of fruits at harvest. However, the question of whether such treatment alters postharvest properties is seldom answered. The effects of an early application of PGRs on postharvest changes on apricots were investigated on cultivar NS-4, grown on Myrobalan rootstock with blackthorn interstock in a 5-year-old orchard. PGR treatments included 50 and 100 ppm of benzyladenine (BA) and 200 ppm of gibberellic acid (GA3), which were applied when the green ovary was surrounded by dying a sepal crown, at the stage where sepals beginning to fall. Apricots at the stage of commercial ripeness were used for the postharvest experiments. Analysis was performed at harvest, after 21 days of cold storage (at 1 ± 1 °C and 80 ± 10% RH), and after 3 days of shelf life (24 ± 2 °C). At harvest, significant differences were observed between treated and untreated fruits regarding flesh firmness, color, ethylene production and respiration rate, flavonoid, carotenoid and citric acid content, while application of BA100 changed TA and TSS. Prolonged cold storage reduced the initial differences in firmness, respiration rate, flavonoid and carotenoid contents, but new differences in fructose, malic and succinic acid contents began to appear. Shelf life reduced the difference in citric acid, but differences in TA, TSS, phenol and flavonoid content appeared. There is no difference in the sensory properties of treated and non-treated fruit after cold storage and shelf life

Could an Early Treatment with GA and BA Impact Prolonged Cold Storage and Shelf Life of Apricot?

Application of plant growth regulators (PGRs) in apricot orchards is a common practice with a goal of improving yield and/or quality of fruits at harvest. However, the question of whether such treatment alters postharvest properties is seldom answered. The effects of an early application of PGRs on postharvest changes on apricots were investigated on cultivar NS-4, grown on Myrobalan rootstock with blackthorn interstock in a 5-year-old orchard. PGR treatments included 50 and 100 ppm of benzyladenine (BA) and 200 ppm of gibberellic acid (GA3), which were applied when the green ovary was surrounded by dying a sepal crown, at the stage where sepals beginning to fall. Apricots at the stage of commercial ripeness were used for the postharvest experiments. Analysis was performed at harvest, after 21 days of cold storage (at 1 ± 1 °C and 80 ± 10% RH), and after 3 days of shelf life (24 ± 2 °C). At harvest, significant differences were observed between treated and untreated fruits regarding flesh firmness, color, ethylene production and respiration rate, flavonoid, carotenoid and citric acid content, while application of BA100 changed TA and TSS. Prolonged cold storage reduced the initial differences in firmness, respiration rate, flavonoid and carotenoid contents, but new differences in fructose, malic and succinic acid contents began to appear. Shelf life reduced the difference in citric acid, but differences in TA, TSS, phenol and flavonoid content appeared. There is no difference in the sensory properties of treated and non-treated fruit after cold storage and shelf life

DataSheet_1_Different life strategies of the three commercially exploited scallop species living under the same environmental conditions.docx

To understand the response of marine species to a changing environment, it is crucial to have deep insight into their main biological traits. This study used a multi-species approach to comparatively analyse the reproductive and growth strategies of three commercially important scallop species. Target taxa were larger sized Mediterranean scallop Pecten jacobeaus, and two smaller sized species Aequipecten opercularis and Flexopecten glaber. Specimens were collected at approximate monthly intervals from February 2017 to October 2018 from a commercial beam trawl in the northern Adriatic area (west coast of the Istria peninsula, 25-35 m depth). Three different complementary methods were applied to obtain comprehensive knowledge about the reproductive cycle including assessment of the gonadosomatic index (GSI), histological analysis of gonad tissue, and measuring oocyte size. Growth strategies of three target species were analyzed using high-resolution stable oxygen isotope data that were temporally aligned on sea water temperature data obtained by AdriSC ROMS model. Results indicate diverse strategies employed by these taxonomically related species exposed to the same environmental conditions. Pecten jacobaeus spawned in the late summer and early fall, while shell growth slowed down during warmer season. Aequipecten opercularis spawned in the winter and slowed down shell deposition process during the cold season. Spawning of F. glaber occurred during early to mid-summer and growth slowed down during warmer season. This study provides an important scientific baseline for sustainable management and future aquaculture attempts of scallops.</p