Academic literature on the topic 'Marine photosynthetic organisms'

Marine diatoms have potential as a biotechnological production platform, especially for lipid-derived products, including biofuels. Here we introduce some features of diatom metabolism, particularly with respect to photosynthesis, photorespiration and lipid synthesis and their differences relative to other photosynthetic eukaryotes. Since structural metabolic modelling of other photosynthetic organisms has been shown to be capable of representing their metabolic capabilities realistically, we briefly review the main approaches to this type of modelling. We then propose that genome-scale modelling of the diatom Phaeodactylum tricornutum, in response to varying light intensity, could uncover the novel aspects of the metabolic potential of this organism.

AbstractIn this work, the photosynthesis model presented by Avilaet al. in 2013 is extended and more scenarios inhabited by ancient cyanobacteria are investigated to quantify the effects of ultraviolet (UV) radiation on their photosynthetic potential in marine environments of the Archean eon. We consider ferrous ions as blockers of UV during the Early Archean, while the absorption spectrum of chlorophyllais used to quantify the fraction of photosynthetically active radiation absorbed by photosynthetic organisms. UV could have induced photoinhibition at the water surface, thereby strongly affecting the species with low light use efficiency. A higher photosynthetic potential in early marine environments was shown than in the Late Archean as a consequence of the attenuation of UVC and UVB by iron ions, which probably played an important role in the protection of ancient free-floating bacteria from high-intensity UV radiation. Photosynthetic organisms in Archean coastal and ocean environments were probably abundant in the first 5 and 25 m of the water column, respectively. However, species with a relatively high efficiency in the use of light could have inhabited ocean waters up to a depth of 200 m and show a Deep Chlorophyll Maximum near 60 m depth. We show that the electromagnetic radiation from the Sun, both UV and visible light, could have determined the vertical distribution of Archean marine photosynthetic organisms.

Ocean warming affects the life history and fitness of marine organisms by, among others, increasing animal metabolism and reducing oxygen availability. In coastal habitats, animals live in close association with photosynthetic organisms whose oxygen supply supports metabolic demands and may compensate for acute warming. Using a unique high-frequency monitoring dataset, we show that oxygen supersaturation resulting from photosynthesis closely parallels sea temperature rise during diel cycles in Red Sea coastal habitats. We experimentally demonstrate that oxygen supersaturation extends the survival to more extreme temperatures of six species from four phyla. We clarify the mechanistic basis of the extended thermal tolerance by showing that hyperoxia fulfills the increased metabolic demand at high temperatures. By modeling 1 year of water temperatures and oxygen concentrations, we predict that oxygen supersaturation from photosynthetic activity invariably fuels peak animal metabolic demand, representing an underestimated factor of resistance and resilience to ocean warming in ectotherms.

We present the first comprehensive and systematic review on the structurally diverse toco-chromanols and -chromenols found in photosynthetic organisms, including marine organisms, and as metabolic intermediates in animals.

What are algae? Algae are organisms that perform photosynthesis; that is, they absorb carbon dioxide and release oxygen (therefore they have chlorophyll, a group of green pigments used by photosynthetic organisms that convert sunlight into energy via photosynthesis) and live in water or in humid places. Algae have great variability and are divided into microalgae, small in size and only visible through a microscope, and macroalgae, which are larger in size, up to more than 50 m (the maximum recorded was 65 m), and have a greater diversity in the oceans. Thus, the term “algae” is commonly used to refer to “marine macroalgae or seaweeds”. It is estimated that 1800 different brown macroalgae, 6200 red macroalgae, and 1800 green macroalgae are found in the marine environment. Although the red algae are more diverse, the brown ones are the largest.

AbstractGeneration of ion electrochemical potential differences by primary active transport can involve energy inputs from light, from exergonic redox reactions and from exergonic ATP hydrolysis. These electrochemical potential differences are important for homoeostasis, for signalling, and for energizing nutrient influx. The three main ions involved are H+, Na+ (efflux) and Cl− (influx). In prokaryotes, fluxes of all three of these ions are energized by ion-pumping rhodopsins, with one archaeal rhodopsin pumping H+into the cells; among eukaryotes there is also an H+ influx rhodopsin in Acetabularia and (probably) H+ efflux in diatoms. Bacteriochlorophyll-based photoreactions export H+ from the cytosol in some anoxygenic photosynthetic bacteria, but chlorophyll-based photoreactions in marine cyanobacteria do not lead to export of H+. Exergonic redox reactions export H+ and Na+ in photosynthetic bacteria, and possibly H+ in eukaryotic algae. P-type H+- and/or Na+-ATPases occur in almost all of the photosynthetic marine organisms examined. P-type H+-efflux ATPases occur in charophycean marine algae and flowering plants whereas P-type Na+-ATPases predominate in other marine green algae and non-green algae, possibly with H+-ATPases in some cases. An F-type Cl−-ATPase is known to occur in Acetabularia. Some assignments, on the basis of genomic evidence, of P-type ATPases to H+ or Na+ as the pumped ion are inconclusive.

The cycling of arsenic in the marine photosynthetic plants and algae was examined by analysing total arsenic concentrations and arsenic species in selected marine photosynthetic organisms from the south-east coast, NSW, Australia. A range of elements required for metabolism in photosynthetic organisms were also analysed to determine if any relationship between these elements and arsenic concentrations occurred. Organisms were selected from salt marsh and mangrove ecosystems, marine inter-tidal and estuarine environments, and two species of marine phytoplankton cultured, to represent the different marine environments that primary producers inhabit. Organisms selected were compared to species within their own environment and then a comparison made between the varying ecosystems. In the salt marsh and mangrove ecosystems, the leaves of four species, the mangrove Avicennia marina, the samphire Sarcocornia quinqueflora, the seablight Suaeda australis, and the seagrass Posidonia australis were sampled from three locations from the south-east coast of NSW using nested sampling. Mean total arsenic concentrations (mean � sd) dry mass for all locations were A. marina (0.38 � 0.18 �g g-1 to 1.2 � 0.7 �g g-1), S. quinqueflora (0.13 � 0.06 �g g-1 to 0.46 � 0.22 �g g-1), S. australis (0.03 � 0.06 �g g-1 to 0.05 � 0.03 �g g-1)and P. australis (0.34 � 0.10 �g g-1 to 0.65 � 0.26 �g g-1). Arsenic concentrations were significantly different between species and locations but were consistently low compared to marine macroalgae species. Significant relationships between As and Fe concentrations for A. marina, S. quinqueflora and P. australis and negative relationship between As and Zn concentrations for S. quinqueflora could partially explain arsenic concentrations in these species. No relationship between As and P concentrations were found in this study. All terrestrial species contained predominantly inorganic arsenic in the water extractable and residue fractions with minor concentrations of DMA in the water-soluble fraction. P. australis also contained dimethylated glycerol and phosphate arsenoriboses. The presence of arsenobetaine, arsenocholine and trimethylated glycerol arsonioribose is most likely due to the presence of epiphytes on fronds on P. australis. In contrast, macroalgae contained higher total arsenic concentrations compared to marine terrestrial angiosperms. Total arsenic concentrations also varied between classes of algae: red macroalgae 4.3 �g g-1 to 24.7 �g g-1, green macroalgae 8.0 �g g-1 to 11.0 �g g-1 and blue green algae 10.4 �g g-1 and 18.4 �g g-1. No significant relations were found between As concentrations and concentrations of Fe, Co, Cu, Mn, Mo, Mg, P and Zn concentrations, elements that are required by macroalgae for photosynthesis and growth. Distinct differences between algal classes were found for the proportion of arsenic species present in the lipid and water-soluble fractions, with green algae having a higher proportion of As in lipids than red or estuarine algae. Acid hydrolysis of the lipid extract revealed DMA, glycerol arsenoribose and TMA based arsenolipids. Within water-soluble extracts, red and blue-green algae contained a greater proportion of arsenic as inorganic and simple methylated arsenic species compared to green algae, which contained predominantly glycerol arsenoribose. Arsenobetaine, arsenocholine and tetramethylarsonium was also present in water-soluble extracts but is not normally identified with macroalgae and is again likely due to the presence of attached epiphytes. Residue extracts contained predominantly inorganic arsenic, most likely associated with insoluble constituents of the cell. Mean arsenic concentrations in the green microalgae Dunaliella tertiolecta were 13.3 �g g-1 to 14.5 �g g-1, which is similar to arsenic concentrations found in green macroalgae in this study. Diatom Phaeodactylum tricornutum arsenic concentrations were 1.62 �g g-1 to 2.08 �g g-1. Varying the orthophosphate concentrations had little effect on arsenic uptake of microalgae. D. tertiolecta and P. tricornutum metabolised arsenic, forming simple methylated arsenic species and arsenic riboses. The ratio of phosphate to glycerol arsenoriboses was higher than that normally found in green macroalgae. The hydrolysed lipid fraction contained DMA arsenolipid (16-96%) with minor proportions of phosphate arsenoribose (4-23%). D. tertiolecta at f/10 phosphate concentration, however, contained glycerol arsenoribose and another arsenic lipid with similar retention as TMAO as well as DMA. The similarities between arsenic species in the water-soluble hydrolysed lipids and water-soluble extracts, especially for P. tricornutum, suggests that cells readily bind arsenic within lipids, either for membrane structure or storage, releasing arsenic species into the cytosol as degradation of lipids occurs. Inorganic arsenic was sequestered into insoluble components of the cell. Arsenic species present in D. tertiolecta at lower phosphate concentrations (f/10) were different to other phosphate concentrations (f/2, f/5), and require further investigation to determine whether this is a species-specific response as a result of phosphate deficiency. Although there are similarities in arsenic concentrations and arsenic species in marine photosynthetic organisms, it is evident that response to environmental concentrations of arsenic in uncontaminated environments is dependent on the mode of transfer from the environment, the influence of other elements in arsenic uptake and the ability of the organism to metabolise and sequester inorganic arsenic within the cell. It is not scientifically sound to generalise on arsenic metabolism in �marine plants� when species and the ecosystem in which they exist may influence the transformation of arsenic in higher marine organisms. There is no evidence to suggest that angiosperms produce AB as arsenic is mostly present as inorganic As, with little or no arsenic present in the lipids. However, marine macro- and microalgae both contain lipids with arsenic moieties that may be precursors for AB transformation. Specifically, the presence of TMA and dimethylated arsenoribose based arsenolipids both can transform to AB via intermediates previously identified in marine organisms. Further identification and characterization of As containing lipids is required.

Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2016
O aparecimento e agravamento de várias doenças, tais como o cancro, diabetes e doenças cardíacas, tem vindo a aumentar ao longo do tempo, levando a uma crescente necessidade de pesquisa de novos compostos com aplicações biomédicas, principalmente de origem natural. As plantas halófitas possuem um enorme potencial biotecnológico por descobrir, sendo consideradas um grande reservatório, praticamente inexplorado, de novas moléculas bioativas ou novas fontes de compostos conhecidos. Assim, este trabalho teve como principal objetivo a avaliação do potencial antitumoral in vitro de extratos naturais de 25 espécies de halófitas. Adicionalmente, foram avaliadas outras atividades biológicas destes extratos, nomeadamente as suas propriedades antioxidantes e despigmentantes in vitro. O perfil fitoquímico dos extratos também foi estudado pela avaliação do seu conteúdo em diferentes grupos fenólicos. A atividade citotóxica in vitro foi avaliada pelo método de brometo de 3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazólio (MTT) usando linhas celulares tumorais de mamíferos (HepG2: hepatocarcinoma humano; HeLa: adenocarcinoma humano; THP1: leucemia monocítica aguda humana; SH-SY5Y: neuroblastoma humano) e uma linha celular de origem não tumoral (S17: linha celular de medula óssea de murino). A atividade antioxidante foi investigada pelos métodos de 2,2-difenil-1-picrilhidrazil (DPPH) e ácido 2,2'-azino-bis(3-etilbenzotiazolina-6-sulfónico) (ABTS), e também determinando o potencial quelante dos iões ferro (Fe2+) e cobre (Cu2+). O perfil fitoquímico incluiu a determinação do conteúdo total de fenólicos, flavonóis, taninos, flavonas e flavonol por espetrofotometria. Por fim, foi avaliado o potencial despigmentante dos extratos através da atividade inibitória da enzima tirosinase. Dos resultados obtidos é evidente que a espécie Inula crithmoides é uma potencial candidata para a pesquisa de compostos anticancerígenos e as espécies Convolvulus (Calystegia) soldanella, Frankenia laevis, F. pulverulenta, Lythrum salicaria e Pistacia lentiscus apresentam um melhor potencial para serem usadas como fonte de moléculas e/ou produtos inovadores com aplicações em diferentes áreas, como a nutracêutica e cosmética, uma vez que apresentaram os melhores resultados para todas as atividades testadas.
The onset and exacerbation of several diseases like cancer, cardiac diseases and diabetes has increased over time, leading to an increasing need for the research of new compounds with biomedical applications, namely those of natural origin. Halophytes have a high biotechnological potential and are considered an almost unexplored reservoir of novel bioactive molecules, or new sources of known compounds. Therefore, this work aimed to evaluate the in vitro antitumoral potential of natural extracts from 25 species of halophytes. Aditionally, it was evaluated other biological activities of these extracts, namely the in vitro antioxidant and skin whitening properties. The phytochemical profile of the extracts was also assessed through the evaluation of their content in different phenolic groups. The in vitro cytotoxic activity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method using mammalian cell lines from tumoral origin (HepG2: human hepatocarcinoma; HeLa: human adenocarcinoma; THP1: human acute monocytic leukemia; SH-SY5Y: human neuroblastoma) and one cell line from non-tumoural origin (S17: murine stromal cell line). Antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays, and also by determining the chelating potential on iron (Fe2+) and copper (Cu2+) ions. Phytochemical profiling included the determination of the total content in phenolics, flavonoids, tannins, flavone and flavonol by spectrophotometric assays. Skin whitening potential was evaluated by the inhibitory activity of the enzyme tyrosinase. From our results it is clear the species Inula crithmoides hold the potential to be a source of antitumoral compounds, while Convolvulus (Calystegia) soldanella, Frankenia laevis, F. pulverulenta, Lythrum salicaria and Pistacia lentiscus have the highest potential to be used as source of molecules and/or innovative products with potential aplications in different areas, such as nutraceutical and cosmetic, since they allowed the best results for all tested activities.

The phytoplanktons are organisms that have limited locomotion about the current being drift in aquatic environment. Another characteristic of phytoplankton their growth and energy are result about photosynthetic process. It is important to emphasize that the phytoplankton is the main primary producer of aquatic environment, it means that, it is the base the aquatic food chain . The organic material produced by phytoplankton is responsible in provide the material and energy which sustains the growth of fish, crustaceans and mollusks, in marine ecosystems. Because of this, it is important to know the factors that interfere with their accumulation in environments mainly in fishing regions. In this way, this study tries to demonstrate the importance of retention time, often caused by hydrological issues, in the variation of phytoplankton biomass in the estuary of the Patos Lagoon (ELP), in Rio Grande/RS. To do that, we created one model that simulates this environment, using techniques of multi-agent-based simulation and its implementation was done with the NetLogo tool.

The benthic environment refers to the region defined by the interface between a body of water and the bottom substrate, including the upper part of the sediments, regardless of the depth and geographical location. Hence, benthic environments, their organisms, and their ecosystems are highly variable as they encompass the full depth range of the oceans with associated changes in physical and chemical properties as well as differences linked to latitudinal and geographical variation. The effects of ocean acidification on the full range of different benthic organisms and ecosystems are poorly known and difficult to ascertain. Nevertheless, by integrating our current knowledge on the effects of ocean acidification on major benthic biogeochemical processes, individual benthic organisms, and observed characteristics of benthic environments as a function of seawater carbonate chemistry, it is possible to draw conclusions regarding the response of benthic organisms and ecosystems to a world of increasingly higher atmospheric CO2 levels. The fact that there are large-scale geographical and spatial differences in seawater carbonate system chemistry (see Chapter 3), owing to both natural and anthropogenic processes, provides a powerful means to evaluate the effect of ocean acidification on marine benthic systems. In addition, there are local and regional environments that experience high-CO2 and low-pH conditions owing to special circumstances such as, for example, volcanic vents (Hall- Spencer et al . 2008 ; Martin et al . 2008 ; Rodolfo-Metalpa et al . 2010), seasonal stratification (Andersson et al . 2007), and upwelling (Feely et al . 2008 ; Manzello et al . 2008 ) that may provide important clues to the impacts of ocean acidification on benthic processes, organisms, and ecosystems. The objective of this chapter is to provide an overview of the potential consequences of ocean acidification on marine benthic organisms, communities, and ecosystems, and the major biogeochemical processes governing the cycling of carbon in the marine benthic environment, including primary production, respiration, calcification, and CaCO3 dissolution. The depth of the euphotic zone, i.e. the depth of water exposed to sufficient sunlight to support photosynthesis, varies depending on a range of factors affecting the clarity of seawater, including river input and run-off to the coastal ocean, upwelling, mixing, and planktonic production.

Now that we have discussed how assemblages of marine soft sediments are structured, we need to consider functional aspects. There are a few main interrelationships that need to be discussed here— inter- and intraspecific competition, feeding and predator–prey interactions, the production of biomass, and the production and delivery of recruiting stages. Other functional aspects, such as the effects of pathogens and parasites and the benefits of association (mutualism, parasitism, symbiosis, etc.) are of less importance in the present discussion. By function we mean the rate processes (i.e. those involving time) that either affect (extrinsic processes) or are inside (intrinsic processes and responses) the organisms that live in sediments. Hence these include primary and secondary production and processes that are mitigated by the organisms that live in sediments, such as nutrient and contaminant fluxes into and out of the sediment. We begin with the historical development of the field since such aspects are often overlooked in these days of electronic searches for references. Functional studies of ecosystems really began with Lindeman´s classic paper (1942) on trophic dynamics. Rather than regarding food merely as particulate matter, Lindeman expressed it in terms of the energy it contained, thereby enabling comparisons to be made between different systems. For example, 1 g of the bivalve Ensis is not equivalent in food value to 1 g of the planktonic copepod Calanus, so the two animals cannot be compared in terms of weight, but they can be compared in terms of the energy units that each gram dry weight contains. The energy unit originally used was the calorie, but this has now been superseded by the joule (J), 1 calorie being equivalent to 4.2 joules. Ensis contains 14 654 J g-1 dry wt and Calanus 30 982 J g-1 dry wt. The basic trophic system is well understood and can be summarized as we showed earlier in Fig. I.8 which gives the links between various trophic levels and the role of competition, organic matter transport, and resource partitioning. In systems fuelled by photosynthesis (so excluding the chemosynthetic deep-sea vent systems), the primary source of energy for any community is sunlight, which is fixed and stored in plant material, which thus constitutes the first trophic level in the ecosystem.

The nature of the relationships between physical and biological processes in the ocean is subtle and complex. Not only do the physical phenomena create a structure, such as a shallow, mixed layer or a front, within which biological processes may proceed, but they also influence the rates of biological processes in many indirect ways. In the ocean, physical phenomena control the distribution of nutrients necessary for phytoplankton photosynthesis. Places with higher kinetic energy have higher concentrations of planktonic organisms, and that makes the whole food web richer (Mann and Lazier 1996). For example, in the midriff region of the Sea of Cortés (Tiburón and Ángel de la Guarda; fig. 1.2), tidal currents are strong, and intense mixing occurs, creating a situation similar to constant upwelling. Thus, primary productivity is high, and this area supports large numbers of sea birds and marine mammals (Maluf 1983). The Gulf of California is a dynamic marginal sea of the Pacific Ocean and has been described as an area of great fertility since the time of early explorers. Gilbert and Allen (1943) described it as fabulously rich in marine life, with waters fairly teeming with multitudes of fish, and to maintain these large numbers, there must be correspondingly huge crops of their ultimate food, the phytoplankton. Topographically the gulf is divided into a series of basins and trenches, deepening to the south and separated from each other by transverse ridges (Shepard 1950; fig. 3.1). Input of nutrients into the gulf from rivers is low and has only local coastal effects. The Baja peninsula has only one, very small river, near 27°N; rivers in mainland Mexico and the Colorado River have dams that divert most of the water for agricultural and urban use. The gulf has three main natural fertilization mechanisms: wind-induced upwelling, tidal mixing, and thermohaline circulation. Upwelling occurs off the eastern coast with northwesterly winds (winter conditions from December through May) and off the Baja California coast with southeasterly winds (summer conditions from July through October), with June and November as transition periods (Álvarez-Borrego and Lara- Lara 1991).

Blue Carbon, which is carbon captured by marine organisms, has recently come into focus as an important factor for climate change initiatives. This carbon is stored in vegetated coastal ecosystems, specifically mangrove forests, seagrass beds and salt marshes. The recognition of the C sequestration value of vegetated coastal ecosystems provides a strong argument for their protection and restoration. Therefore, it is necessary to improve scientific understanding of the mechanisms that stock control C in these ecosystems. However, the contribution of Blue Carbon sequestration to atmospheric CO2 in shallow waters is as yet unclear, since investigations and analysis technology are ongoing. In this study, Blue Carbon sinks by Zostera marina were evaluated in artificial (Gotenba) and natural (Matsunase) Zostera beds in Ise Bay, Japan. 12-hour continuous in situ photosynthesis and oxygen consumption measurements were performed in both areas by using chambers in light and dark conditions. The production and dead amount of Zostera marina shoots were estimated by standing stock measurements every month. It is estimated that the amount of carbon storage as Blue Carbon was 237g-C/m2/year and 197g-C/m2/year in the artificial and natural Zostera marina beds, respectively. These results indicated that Zostera marina plays a role towards sinking Blue Carbon.

Blue Carbon, which is carbon captured by marine organisms, has recently come into focus as an important factor for climate change initiatives. This carbon is stored in vegetated coastal ecosystems, specifically mangrove forests, seagrass beds and salt marshes. The recognition of the C sequestration value of vegetated coastal ecosystems provides a strong argument for their protection and restoration. Therefore, it is necessary to improve scientific understanding of the mechanisms that stock control C in these ecosystems. However, the contribution of Blue Carbon sequestration to atmospheric CO2 in shallow waters is as yet unclear, since investigations and analysis technology are ongoing. In this study, Blue Carbon sinks by Zostera marina were evaluated in artificial (Gotenba) and natural (Matsunase) Zostera beds in Ise Bay, Japan. 12-hour continuous in situ photosynthesis and oxygen consumption measurements were performed in both areas by using chambers in light and dark conditions. The production and dead amount of Zostera marina shoots were estimated by standing stock measurements every month. It is estimated that the amount of carbon storage as Blue Carbon was 237g-C/m2/year and 197g-C/m2/year in the artificial and natural Zostera marina beds, respectively. These results indicated that Zostera marina plays a role towards sinking Blue Carbon.