Geoengineering - ocean iron fertilization method

Geoinženjering je ljudska intervencija u prirodne procese kojom se nastoje ukloniti/ublažiti posljedice klimatskih promjena. Jedna od potencijalnih metoda geoinženjeringa je fertilizacija oceana željezom. Metoda uključuje dodavanje željeznih spojeva u HNLC oceanska područja gdje je rast fitoplanktona ograničen upravo tim elementom, čime se nastoji potaknuti primarna proizvodnja i biološka pumpa te posljedično smanjiti količina ugljikovog dioksida u atmosferi. U radu je definiran geoinženjering, moguća provedba te ciljevi koji se tim metodama žele ostvariti. Opisani su eksperimenti fertilizacije oceana željezom te kemijska svojstva željeza, njegova distribucija u oceanu i uloga u fitoplanktonu, bitni čimbenici koje je potrebno proučiti za uspjeh ove metode. Predstavljeni su neželjeni učinci koje fertilizacije oceana može uzrokovati, prijedlozi za poboljšanje efikasnosti metode, važnost predviđanja rizika vraćanja odvojenog CO2 u atmosferu te razvijanja pravno određenih radnih okvira koji osiguravaju da se fertilizacija oceana željezom provodi u kontroliranim uvjetima.Geoengineering is a deliberate human intervention in the ecosystem processes in order to counteract anthropogenic climate change. Ocean iron fertilization as a potential method in geoengineering is suggested. Method is based on addition of iron compounds to HNLC oceanic regions where primary production is limited by iron, making primary production and biological pump more intense, thereby reducing the concentration of carbon dioxide in atmosphere. In this work we present the definiton of geoengineering, main goals and proposed approaches. Iron fertilization experiments are described as well as chemical properties, distribution in the ocean and role of iron in phytoplankton community, all which are important for understanding the method. Side effects and efficiency of method are described. We present importance of developing models that can predict risks of implementing the method and importance of developing acceptable framework for research on ocean iron fertilization

Optimization of artificial light in the cultivation of laboratory diatom cultures Achnanthes elongata and Poulinea lepidochelicola

Dijatomeje su jednostanični fotoautotrofni eukariotski organizmi koji nastanjuju plankton i bentos slatkovodnih i morskih ekosustava. Zajednice epizojskih dijatomeja također nastanjuju površine životinja poput ptica, kitova, te slatkovodnih i morskih kornjača. Vrste Achnanthes elongata i Poulinea lepidochelicola su nedavno opisane nove vrste dijatomeja s oklopa morskih kornjača. Stoga je cilj ovog istraživanja bio utvrditi optimalno umjetno osvjetljenje za laboratorijski uzgoj monokultura dvije tek opisane vrste dijatomeja, izolirane s oklopa i kože glavate želve (Caretta caretta) iz Jadranskog mora. U eksperimentu su korištena 3 soja vrste Achnanthes elongata i 2 soja vrste Poulinea lepidochelicola. Za svaki soj inokulirana su 2 biološka replikata s poznatim brojem stanica. Kulture su smještene u zatvorenom sustavu komore za rast stanica u uvjetima LED svjetlosti dvije različite temperature: umjereno-bijele boje temperature 5000 K i bijele boje temperature 6500 K. Biološki replikati praćeni su 39-40 dana te je određivana njihova brojnost. Za sve ispitivane sojeve dobivene su krivulje rasta iz kojih su vidljive faza prilagođavanja, eksponencijalna faza, te faza mirovanja. Stope rasta svih sojeva bile su unutar intervala od 0,30 - 0,58 dioba po danu, a vremena udvostručenja populacija od 1,31-2,28 dana. Rezultati ovoga rada pokazuju da sojevi obje vrste dijatomeja postižu veću gustoću i bolji rast ukoliko se u laboratoriju uzgajaju pri umjereno-bijeloj LED svjetlosti temperature 5000 K.Diatoms are photoautotrophic eukaryotic microorganisms that are inhabiting phytoplankton and phytobentos of freshwater and marine ecosystems. Epizoic diatom communities are found on animals such as birds, whales, freshwater and sea turtles. Species Achnanthes elongata and Poulinea lepidochelicola are newly described epizoic diatoms living on the carapaces of sea turtles. The aim of the research was to determine the optimal artificial light for the cultivation of monocultures of these recently described diatoms isolated from the carapace and skin of loggerhead sea turtle (Caretta caretta) from the Adriatic Sea. Three strains of Achanthes elongata and two strains of Poulinea lepidochelicola were chosen for the experiments, and for each strain two biological replicates were used. The experiment started with a known number of cells inoculated for each replicate. Samples were placed in the closed culture room system with two different LED light illumination: the cold white light temperature 5000 K and warm white light temperature 6500 K. Biological replicates were observed for 39-40 days and diatom cells were counted. Growth curves were obtained that show different phases of growth: lag phase, exponential phase and stationary phase. The growth rates of all strains were within range of 0,30-0,58 division per day and doubling population times ranged between 1,31 and 2,28 days. Strains from both species grow better and achieve larger cell numbers under warm white light temperature 5000 K

Optimization of artificial light in the cultivation of laboratory diatom cultures Achnanthes elongata and Poulinea lepidochelicola

Dijatomeje su jednostanični fotoautotrofni eukariotski organizmi koji nastanjuju plankton i bentos slatkovodnih i morskih ekosustava. Zajednice epizojskih dijatomeja također nastanjuju površine životinja poput ptica, kitova, te slatkovodnih i morskih kornjača. Vrste Achnanthes elongata i Poulinea lepidochelicola su nedavno opisane nove vrste dijatomeja s oklopa morskih kornjača. Stoga je cilj ovog istraživanja bio utvrditi optimalno umjetno osvjetljenje za laboratorijski uzgoj monokultura dvije tek opisane vrste dijatomeja, izolirane s oklopa i kože glavate želve (Caretta caretta) iz Jadranskog mora. U eksperimentu su korištena 3 soja vrste Achnanthes elongata i 2 soja vrste Poulinea lepidochelicola. Za svaki soj inokulirana su 2 biološka replikata s poznatim brojem stanica. Kulture su smještene u zatvorenom sustavu komore za rast stanica u uvjetima LED svjetlosti dvije različite temperature: umjereno-bijele boje temperature 5000 K i bijele boje temperature 6500 K. Biološki replikati praćeni su 39-40 dana te je određivana njihova brojnost. Za sve ispitivane sojeve dobivene su krivulje rasta iz kojih su vidljive faza prilagođavanja, eksponencijalna faza, te faza mirovanja. Stope rasta svih sojeva bile su unutar intervala od 0,30 - 0,58 dioba po danu, a vremena udvostručenja populacija od 1,31-2,28 dana. Rezultati ovoga rada pokazuju da sojevi obje vrste dijatomeja postižu veću gustoću i bolji rast ukoliko se u laboratoriju uzgajaju pri umjereno-bijeloj LED svjetlosti temperature 5000 K.Diatoms are photoautotrophic eukaryotic microorganisms that are inhabiting phytoplankton and phytobentos of freshwater and marine ecosystems. Epizoic diatom communities are found on animals such as birds, whales, freshwater and sea turtles. Species Achnanthes elongata and Poulinea lepidochelicola are newly described epizoic diatoms living on the carapaces of sea turtles. The aim of the research was to determine the optimal artificial light for the cultivation of monocultures of these recently described diatoms isolated from the carapace and skin of loggerhead sea turtle (Caretta caretta) from the Adriatic Sea. Three strains of Achanthes elongata and two strains of Poulinea lepidochelicola were chosen for the experiments, and for each strain two biological replicates were used. The experiment started with a known number of cells inoculated for each replicate. Samples were placed in the closed culture room system with two different LED light illumination: the cold white light temperature 5000 K and warm white light temperature 6500 K. Biological replicates were observed for 39-40 days and diatom cells were counted. Growth curves were obtained that show different phases of growth: lag phase, exponential phase and stationary phase. The growth rates of all strains were within range of 0,30-0,58 division per day and doubling population times ranged between 1,31 and 2,28 days. Strains from both species grow better and achieve larger cell numbers under warm white light temperature 5000 K

Optimization of artificial light in the cultivation of laboratory diatom cultures Achnanthes elongata and Poulinea lepidochelicola

Dijatomeje su jednostanični fotoautotrofni eukariotski organizmi koji nastanjuju plankton i bentos slatkovodnih i morskih ekosustava. Zajednice epizojskih dijatomeja također nastanjuju površine životinja poput ptica, kitova, te slatkovodnih i morskih kornjača. Vrste Achnanthes elongata i Poulinea lepidochelicola su nedavno opisane nove vrste dijatomeja s oklopa morskih kornjača. Stoga je cilj ovog istraživanja bio utvrditi optimalno umjetno osvjetljenje za laboratorijski uzgoj monokultura dvije tek opisane vrste dijatomeja, izolirane s oklopa i kože glavate želve (Caretta caretta) iz Jadranskog mora. U eksperimentu su korištena 3 soja vrste Achnanthes elongata i 2 soja vrste Poulinea lepidochelicola. Za svaki soj inokulirana su 2 biološka replikata s poznatim brojem stanica. Kulture su smještene u zatvorenom sustavu komore za rast stanica u uvjetima LED svjetlosti dvije različite temperature: umjereno-bijele boje temperature 5000 K i bijele boje temperature 6500 K. Biološki replikati praćeni su 39-40 dana te je određivana njihova brojnost. Za sve ispitivane sojeve dobivene su krivulje rasta iz kojih su vidljive faza prilagođavanja, eksponencijalna faza, te faza mirovanja. Stope rasta svih sojeva bile su unutar intervala od 0,30 - 0,58 dioba po danu, a vremena udvostručenja populacija od 1,31-2,28 dana. Rezultati ovoga rada pokazuju da sojevi obje vrste dijatomeja postižu veću gustoću i bolji rast ukoliko se u laboratoriju uzgajaju pri umjereno-bijeloj LED svjetlosti temperature 5000 K.Diatoms are photoautotrophic eukaryotic microorganisms that are inhabiting phytoplankton and phytobentos of freshwater and marine ecosystems. Epizoic diatom communities are found on animals such as birds, whales, freshwater and sea turtles. Species Achnanthes elongata and Poulinea lepidochelicola are newly described epizoic diatoms living on the carapaces of sea turtles. The aim of the research was to determine the optimal artificial light for the cultivation of monocultures of these recently described diatoms isolated from the carapace and skin of loggerhead sea turtle (Caretta caretta) from the Adriatic Sea. Three strains of Achanthes elongata and two strains of Poulinea lepidochelicola were chosen for the experiments, and for each strain two biological replicates were used. The experiment started with a known number of cells inoculated for each replicate. Samples were placed in the closed culture room system with two different LED light illumination: the cold white light temperature 5000 K and warm white light temperature 6500 K. Biological replicates were observed for 39-40 days and diatom cells were counted. Growth curves were obtained that show different phases of growth: lag phase, exponential phase and stationary phase. The growth rates of all strains were within range of 0,30-0,58 division per day and doubling population times ranged between 1,31 and 2,28 days. Strains from both species grow better and achieve larger cell numbers under warm white light temperature 5000 K

Phytoplankton diversity and chemotaxonomy in contrasting North Pacific ecosystems

Background: Phytoplankton is the base of majority of ocean ecosystems. It is respon-sible for half of the global primary production, and different phytoplankton taxa have a unique role in global biogeochemical cycles. In addition, phytoplankton abundance and diversity are highly susceptible to climate induced changes, hence monitoring of phytoplankton and its diversity is important and necessary. Methods: Water samples for phytoplankton and photosynthetic pigment analyses were collected in boreal winter 2017, along transect in the North Pacific Subtropical Gyre (NPSG) and the California Current System (CCS). Phytoplankton community was analyzed using light and scanning electron microscopy and photosynthetic pigments by high-performance liquid chromatography. To describe distinct ecosystems, monthly average satellite data of MODIS Aqua Sea Surface temperature and Chlorophyll a concentration, as well as Apparent Visible Wavelength were used. Results: A total of 207 taxa have been determined, mostly comprised of coccol-ithophores (35.5%), diatoms (25.2%) and dinoflagellates (19.5%) while cryptophytes, phytoflagellates and silicoflagellates were included in the group "others" (19.8%). Phytoplankton spatial distribution was distinct, indicating variable planktonic dispersal rates and specific adaptation to ecosystems. Dinoflagellates, and nano-scale coccol-ithophores dominated NPSG, while micro-scale diatoms, and cryptophytes prevailed in CCS. A clear split between CCS and NPSG is evident in dendogram visualising LINK -TREE constrained binary divisive clustering analysis done on phytoplankton counts and pigment concentrations. Of all pigments determined, alloxanthin, zeaxanthin, divinyl chlorophyll b and lutein have highest correlation to phytoplankton counts. Conclusion: Combining chemotaxonomy and microscopy is an optimal method to determine phytoplankton diversity on a large-scale transect. Distinct communities between the two contrasting ecosystems of North Pacific reveal phytoplankton groups specific adaptations to trophic state, and support the hypothesis of shift from micro -to nano-scale taxa due to sea surface temperatures rising, favoring stratification and oligotrophic conditions

Phytoplankton diversity and chemotaxonomy in contrasting North Pacific ecosystems

Background Phytoplankton is the base of majority of ocean ecosystems. It is responsible for half of the global primary production, and different phytoplankton taxa have a unique role in global biogeochemical cycles. In addition, phytoplankton abundance and diversity are highly susceptible to climate induced changes, hence monitoring of phytoplankton and its diversity is important and necessary. Methods Water samples for phytoplankton and photosynthetic pigment analyses were collected in boreal winter 2017, along transect in the North Pacific Subtropical Gyre (NPSG) and the California Current System (CCS). Phytoplankton community was analyzed using light and scanning electron microscopy and photosynthetic pigments by high-performance liquid chromatography. To describe distinct ecosystems, monthly average satellite data of MODIS Aqua Sea Surface temperature and Chlorophyll a concentration, as well as Apparent Visible Wavelength were used. Results A total of 207 taxa have been determined, mostly comprised of coccolithophores (35.5%), diatoms (25.2%) and dinoflagellates (19.5%) while cryptophytes, phytoflagellates and silicoflagellates were included in the group “others” (19.8%). Phytoplankton spatial distribution was distinct, indicating variable planktonic dispersal rates and specific adaptation to ecosystems. Dinoflagellates, and nano-scale coccolithophores dominated NPSG, while micro-scale diatoms, and cryptophytes prevailed in CCS. A clear split between CCS and NPSG is evident in dendogram visualising LINKTREE constrained binary divisive clustering analysis done on phytoplankton counts and pigment concentrations. Of all pigments determined, alloxanthin, zeaxanthin, divinyl chlorophyll b and lutein have highest correlation to phytoplankton counts. Conclusion Combining chemotaxonomy and microscopy is an optimal method to determine phytoplankton diversity on a large-scale transect. Distinct communities between the two contrasting ecosystems of North Pacific reveal phytoplankton groups specific adaptations to trophic state, and support the hypothesis of shift from micro- to nano-scale taxa due to sea surface temperatures rising, favoring stratification and oligotrophic conditions

Mercury Exposure Assessment in Mother–Infant Pairs from Continental and Coastal Croatia

The main source of mercury (Hg) exposure in the general population is fish. Another possible source is dental amalgam. Here, we compare the levels of Hg and selenium (Se) in samples of maternal and fetal origin collected shortly after childbirth of healthy postpartum women in the coastal (n = 96) and continental (n = 185) areas of Croatia related to maternal seafood/fish consumption. We also evaluated Hg concentrations and maternal serum metallothionein (MT2) concentrations in relation to the number of dental amalgam fillings, and MT2A-5A/G (rs28366003) polymorphism. The levels of Hg and Se in maternal hair and blood/serum, placenta and cord blood/serum increased in relation to increasing fish consumption with the highest values in subjects from the coast. The concentrations of each element and between elements correlated across the matrices. Increasing amalgam number correlated linearly with increased Hg levels in maternal and cord serum and was not associated with serum MT2. No association of MT2A-5A/G polymorphism and Hg or Se levels were found. The results confirmed higher fish consumption in coastal vs. continental Croatia and increases of both Hg and Se related to fish consumption in all analyzed samples. Increased blood Hg reflected the predominant MeHg share from seafood, while increased serum Hg matched exposure from dental amalgams

Phytoplankton Diversity and Co-Dependency in a Stratified Oligotrophic Ecosystem in the South Adriatic Sea

The oligotrophy of the southern Adriatic Sea is characterized by seasonal stratification which enables nutrient supply to the euphotic layer. A set of interdisciplinary methods was used to elucidate the diversity and co-dependency of bacterio- and phytoplankton of the water column during the stratification period of July 2021. A total of 95 taxa were determined by microscopy: 58 diatoms, 27 dinoflagellates, 6 coccolithophores, and 4 other autotrophs, which included Chlorophyceae, Chrysophyceae, and Cryptophytes. Nanophytoplankton abundances were higher in comparison to microphytoplankton. The prokaryotic plankton community as revealed by HTS was dominated by Proteobacteria (41–73%), Bacteroidota (9.5–27%), and cyanobacteria (1–10%), while the eukaryotic plankton community was composed of parasitic Syndiniales (45–80%), Ochrophyta (2–18%), Ciliophora (2–21%), Chlorophytes (2–4%), Haptophytes (1–4%), Bacillariophyta (1–13%), Pelagophyta (0.5–12%) and Chrysophyta (0.5–3%). Flow cytometry analysis has recorded Prochlorococcus and photosynthetic picoeukaryotes as more abundant in deep chlorophyll maximum (DCM), and Synechococcus and heterotrophic bacteria as most abundant in surface and thermocline layers. Surface, thermocline, and DCM layers were distinct considering community diversity, temperature, and nutrient correlations, while extreme nutrient values at the beginning of the investigating period indicated a possible nutrient flux. Nutrient and temperature were recognized as the main environmental drivers of phytoplankton and bacterioplankton community abundance