Why is marine algae important

In addition, marine algal genomics encourages the understanding of algae allowing them to serve as model organisms [ 32 ]. Subsequently, studies have used several marine algae as model organisms such as the microalga O. Transcriptomics gives insights into genome expression that lends a view on gene structure, gene expression regulation, gene product function and the dynamics of the genome.

Over the years techniques used for transcriptome analysis have evolved from the initial expression sequencing tag EST strategy to gene chips, and now the RNA-seq and bioinformatics analysis Figure 3 [ 50 ]. Dong and Chen [ 50 ] and Morozova et al. Methodology for transcriptomics analysis—adaptation from Tang et al. The relevance of transcriptomics exemplified by the studies herein mentioned ranges from the understanding of overexpression of respective enzymes in a particular biochemical pathway for pertinent applications to that of carbon capture.

The ability of marine algae to produce secondary metabolites in response to an environmental change is well understood. Radical changes are observed at the first gene expression level i. Transcriptomics studies on the response to environmental variability include E. Many unprecedented reactions such as the upregulation of many unknown genes along with a number of gene coding for chlorophyll a and c binding proteins were also observed [ 6 ].

In response to high copper contaminations, E. Ritter et al. A comparative analysis of the gene expression of S. The study also provided important points of information for other functional genes identification in kelp [ 55 ]. On the other hand, the long serial analysis of gene expression of the marine coccolithophore E. The transcriptomic analysis of P. Furthermore, the transcriptome analysis of marine macroalgae of economic importance in China covering two groups Rhodophyta and Phaeophyta—3 classes, 11 orders and 19 families—helped to decipher the proteins involved in the ability of these macroalgae to cope with extreme environmental variabilities [ 57 ].

The study reported three types of phycobiliproteins in Gracilaria spp. Moreover, the study also helped to annotate the whole set of macroalgal C4-pathway genes including genes encoding pyruvate kinase, phosphoenolpyruvate carboxylase and others [ 57 ].

Nyvall et al. The same study established the phylogenetic relationships of the bacterial and brown algal enzymes—mannuronan Cepimerases in the alginate biosynthesis.

Proteomics involves different separation techniques to multiple analyses and different identification tools Figure 4. Graves and Haystead [ 58 ] provide an in-depth review of proteomics techniques. Methodology for proteomics—modified from Graves and Haystead [ 58 ]. For the past decade or so, several novel marine algal proteins have been identified by two-dimensional electrophoresis DE and mass spectrometry MS including proteins from the macroalga Gracilaria changii [ 59 ], and the microalgae Dunaliella bardawil [ 60 ] and Nannochloropsis oculata [ 61 ].

Nevertheless, proteomics does not end with the identification of a particular protein, it also helps to uncover the underlying function of the latter including its role in evolution as well as taxonomic studies and biochemical pathways [ 8 , 61 , 62 ]. Proteomic studies on algae are still relatively limited compared to higher plants.

So far, it is the freshwater Microalga — Chlamydomonas reinhardtii — that has been thoroughly studied from various omics-angle. Nonetheless, there are other marine algae that have been studied for several biochemical pathways such as the urea cycle [ 62 ], glycolysis [ 8 ] and Calvin-Benson cycle [ 64 ] among others.

The shotgun proteomics technique is being profusely applied to the study of marine algal proteome. The first shotgun proteomics analysis of T. Le Bihan et al. Liska et al. The study revealed the upregulation of gene coding for several enzymes including plasma membrane carbonic anhydrases, Rubisco and other fundamental enzymes of the Calvin-Benson cycle, enzymes for adenosine triphosphate ATP and redox energy, glucosephosphate dehydrogenase and 6-phosphogluconate dehydrogenase, and enzymes in amino acids biosynthesis [ 64 ].

High copper concentrations also affect the metabolism of marine algae. Although copper is an essential micronutrient to macroalgae, it can be toxic at high concentrations. Nonetheless, it has been reported that the brown macroalgae Scytosiphon spp. Twenty-nine proteins were identified including 19 overexpressed and hypothetically involved in copper tolerance.

It is noteworthy that marine macroalgal proteomic studies are relatively uncommon and studies of those under stress are further limited but there are some whose expressed proteome in response to an environmental stress has been explored and these include Pyropia orbicularis and S. A decline in photosynthetic activity but an increase in the antioxidant activity by the upregulation of gene coding for phycobiliproteins and production of proteins such as superoxide dismutase were observed.

On the other hand, S. Additionally, proteomic studies are also being carried out to investigate the biosynthesis mechanism of harmful marine algae particularly in relation to human health and safety [ 67 ]. Saxitoxin, for instance, is associated with paralytic shellfish poisoning. For a long time, little was known of the biosynthetic pathway of saxitoxin synthesis but studies are now revealing the enzymes implicated [ 68 ].

Marine algal toxins are being considered for potential commercial applications such as the use of saxitoxin and tetrodotoxin as an anaesthetic [ 69 ] and insights of their production would be an advantage for the industry. Methodology for metabolomics—adaptation from Verpoorte et al. Owing to the relationship between genes and proteins, proteomics became the main focus of the post-genomic era. However, being of subordinate relevance to the evaluation of phenotypic responses of organisms, proteomics gradually took the backseat while metabolomics was brought in the limelight [ 70 ].

The metabolites of an organism can be categorised as primary fundamental for cell development and are continually produced, e. Secondary metabolites of marine algae are of major interest but not all can be expressed at all times.

Verpoorte et al. Roessner and Bowne [ 71 ] summarised metabolomics approaches as follows: target analysis, metabolite profiling, metabolomics and metabolic fingerprinting Figure 5. As metabolomics depicts the physiological states of any organism including marine algae, the research database of this omics surpasses that of proteomics as well as transcriptomics in the functional genomics arena. The exometabolome and endometabolome of both marine microalgae and macroalgae have been thoroughly studied for multiple purposes including ecology [ 72 ], physiological states [ 73 ] and applications in multiple sectors such as health [ 34 , 74 ] and energy [ 16 ].

Barofsky et al. It was observed that some of the metabolites exuded acted as info-chemicals for the microalgal ecology very much like quorum sensing by bacteria. Furthermore, Vidoudez and Pohnert [ 73 ] untangled the general patterns of the metabolism of S.

Sugar and amino acids metabolisms were reported to be the highest in the exponential phase and accumulating in the night, whereas glucose and glutamate exhibited other different characteristics. The declining phase was characterised by the catabolism-related metabolites and the increase in terpenes as well as putrescine. The studies indicate that investigations dealing with both ecological and physiological aspects of diatoms need to consider the dynamic changing nature of their metabolism. Barre et al.

NMR has also been used in metabolic profiling of macroalgae such as L. The understanding of metabolisms e. Its application as a panacea for the benefits of the society is what is mostly driving the marine algal metabolomics. A concrete example is the quest for cancer remedy. Cancer is the gangrening scourge of the modern world and is on the forefront in the research arenas of several organisms including marine algae.

Studies on the red macroalga Callophycus serratus by Lin et al. The metabolites of C. The bromophycolides presented cytotoxicity towards selected human cancer cell lines. It is noteworthy that one of the bromophycolides exhibited submicromolar activity against human malaria parasite Plasmodium falciparum [ 34 ]. The C. The plausible applications of marine algal metabolites are ever expanding. Gupta et al. The metabolic level regulations of choline containing lipids of marine macroalgae, presence of acetate and lactate for all the macroalgal species indicating the existence of fermentative regulatory switching and identification of non-proteinogenic cysteine-oxoforms such as hypotaurine in U.

The hypotaurine looks very promising for non-communicable diseases and can be an anti-hypertensive and a hypocholesterolemic agent. It is noteworthy that a limited number of studies have been carried out on the exometabolomes for pertinent application such as therapeutic ones. Kumari et al. The oxylipins extracted from the medium were analysed using HPLC. Even if the study indicated low hydroxyl-oxylipin content, the compound being similar to those of mammalian oxylipins could serve as substitute for the treatment of inflammatory diseases, cancer and atherosclerosis among others.

The metabolome composition is affected by mutations and endogenous as well as exogenous stimuli. Goulitquer et al. As is the case with proteomics, the nature and concentration of metabolites vary with respect to environmental stress conditions. An inexhaustive list of such metabolomic studies includes defence response of the macroalga Gracilaria vermiculophylla [ 79 ] and others.

Chen et al. The aim of system biology is to establish a profound understanding of the behaviour of and the interaction between the individual components of the organisms [ 4 ]. The basic principle of system biology is modelling, which unveils the dynamics of the organisms. To date, studies on marine macroalgal and microalgal system biology are very limited.

One of the issues highlighted in the study was the importance of non-coding RNAs in the regulation of the abiotic stress response mechanisms. Furthermore, proteomics and transcriptomics complement each other as do metabolomics and transcriptomics. Allen et al. The study revealed several issues including the downregulation of photosynthesis, mitochondrial electron transport and nitrate intake, but there was a compensation of nitrogen and carbon from protein and carbohydrate breakdown, and adaptations to the biosynthesis of chlorophyll and the metabolism of pigment.

System biology is unravelling the novelty of metabolic capabilities and potential bioproducts of marine algae. Genomics, transcriptomics, proteomics and metabolomics are leading to the discovery of innumerable novel molecules, which are proving to be crucial resources and assets in emerging industries such as nutraceuticals, biofuels, pharmaceuticals and cosmeceuticals based on marine algae.

However, it is far from being an exhaustive review. The array of marine algae and their derivatives are gaining increasing recognition worldwide. In addition to the panoply of ecosystem services that marine microalgae and macroalgae provide, the extensive range of biotechnological exploitation and the subsequent industrial applications of these organisms as biological factories are thoroughly documented. Marine algae are being widely used Figure 6 —both at the molecular and organismal levels—as food [ 85 , 86 ] and nutraceuticals [ 87 ], animal and fish feed [ 86 , 88 ], biofertiliser [ 89 ], bioplastics [ 90 ], pharmaceuticals [ 91 ], cosmeceuticals [ 91 — 93 ], fluorophores [ 94 ], food colourants and textile dyes [ 95 , 96 ], and biofuels [ 16 ] as well as for phycoremediation [ 97 — 99 ] Table 1.

Applications of marine algae. Phycoremediation is the use of algae to destroy or biotransform pollutants to innocuous level [ ]. Marine algae are being considered for their multiple advantages. Marine algae can remediate heavy metal contamination [ 97 , 98 , ], contribute to wastewater treatment [ 99 ], lower the atmospheric carbon dioxide [ 14 , 15 ] via photosynthesis [ ] and produce biomass for industrial applications [ 15 , ].

Carsky and Mbhele [ ], Lawton et al. S argassum spp. On the other hand, six Ulva spp. Ulva ohnoi was found to be the most appropriate one as it had high growth rates, tolerance to extreme environment and good ability to use multiple sources of nitrogen [ ].

Imani et al. Increasing atmospheric carbon dioxide concentration is another major environmental threat environmental threat affecting the balance of nature. Brennan and Owende [ ] enumerated three sources of CO 2 , namely, the atmosphere, industrial power plants and soluble carbonate. The desirable traits of microalgae, we assume which applies to algae in general, were considered to be the high growth rates, high metabolism of CO 2 , high tolerance to SO x and NO x , biosynthesis of economically viable products, non-tedious harvesting methods, and tolerance to extreme environmental conditions.

Sydney et al. Nonetheless, a high lipid accumulation was also noted in D. In addition, Moheimani et al. It was also noted that CO 2 is one of the photosynthetic rate limiting factor for marine phytoplankton. Chiu et al. The study also showed that Chlorella sp. Chung et al. They stated that large-scale seaweed cultivation is attractive owing to their decades-proven, low-cost technologies and the panoply uses of their products. They provided an overview of the Korean Coastal CO 2 Removal Belt which promotes the removal of atmospheric CO 2 via marine forests—approximately 10 tonnes of CO 2 per hectare yearly for the brown macroalga Ecklonia.

While we are discussing food, it is important to note that those who like salmon, oysters, lobster, and every other form of seafood must offer their thanks to the algae, since the algae are the primary producers in aquatic ecosystems—the starting point in the food chain or food web and thus the sine qua non for the fine seafood some of us love. We will start with the big ones and then cover the little ones. Everyone who has spent time along the ocean coasts or around lakes and ponds, has noticed some of the big algae, or macroscopic algae and these easily visible algae are mostly three groups with simple, colorful names.

They are the green algae, the red algae, and the brown algae or the Chlorophyta, Rhodophyta, and Phaeophyta respectively. Books can be, and have been, written about each group, but just a few essential facts will serve as a quick introduction to each group.

There are an estimated 6, to 8, species of green algae and one should remember the number is truly just an estimate and ninety percent of them are freshwater rather than marine. As mentioned above, a freshwater green algal ancestor conquered the land and gave rise to the land plant flora, in fact the green algae are in a monophyletic or natural group with the land plants.

The green algae and the land plants all share a common ancestor, and, all descendants of that common ancestor are either green algae or land plants. Although many of the green algae are large macroscopic seaweeds, they can also be tiny unicellular or colonial organisms. Given these examples of invasive species, the question arises: Are these algae bad?

The algae did not invade on their own, they were released into or transported to new environments by people. There are ca. Although there are some unicellular red algae, most are macroscopic algae often growing abundantly on rocky shores.

The red alga Porphya is also harvested as Nori and is the dark purple—reddish wrapper used in sushi around the world. The red algae are among the most beautiful seaweeds and many of them have been found to contain useful pharmaceutical compounds with antibacterial, antiviral, or anti-cancer effects.

There are only 1, to 2, or so species and they are almost entirely marine even more so than the red algae. This group includes such famous entities as Sargassum of Sargasso Sea fame and the giant kelp Macrocystis which forms large forests and is harvested for alginic acid, a commercially important polysaccharide with a host of industrial uses from thickening food products to glossy paper production to beer brewing.

Like the red algae, the browns are a source of potential pharmaceutical compounds. Like the greens and the reds, the brown algae are often major components of the rocky intertidal zone and thus are exposed at low tide and must withstand both desiccation and, in many cases, the full force of major wave action as the tides come in. Although the seaweeds are often beautiful and often very noticeable too noticeable when there are large blooms or when storms wash too much up on the beaches , they largely occur in coastal regions at or near the shoreline.

In contrast the phytoplankton are microscopic and some are very beautiful. Although phytoplankton are often not noticeable at all compared to the seaweeds , phytoplankton can be actually very noticeable when there is a massive bloom such as the red tides and other Harmful Algal Blooms [HABs].

In such cases, the phytoplankton can change the color of the ocean for miles and poison the air. These algae are tiny, but the important thing to note is that the oceans and the major lakes of the world provide a vast habitat for the phytoplankton and they can achieve almost unimaginable densities.

There are several interesting groups of marine and freshwater phytoplankton not covered in this brief introduction and there are important green algae phytoplankton—especially in freshwater ecosystems, but this review will stick to the marine Big 4 or Pasturage of the Seas, that is, the diatoms, dinoflagellates, coccolithophorids, and the blue—green algae.

Despite living in glass houses, the diatoms in some cases actually move around and at certain times even manage to have sex. But perhaps the single most important thing to note is that diatoms are often very abundant and, thus, important members of their respective ecosystems. The glass houses or more scientifically, the frustules survive for thousands of years and in fact diatomaceous earth diatomite used in pool filter systems and in car polishes is found in massive deposits sometimes hundreds of feet thick.

There are 12, known species of diatoms and some estimate that there may be as many as 60, to , species Hasle and Syvertsen The eukaryotic dinoflagellates are very abundant normally and can achieve densities of 10 7 —10 8 cells per liter Graham and Wilcox during blooms which are often HABs associated with paralytic shellfish poisoning, amnesic shellfish poisoning, diarrhetic shellfish poisoning, neurotoxic shelfish poisoning, and ciguatera fish poisoning.

Given the litany of obnoxious poisoning that can be caused by dinoflagellates, one must return to the question: Are these algae bad? First, the dinoflagellates are mostly harmless sources of oxygen and food for other organisms.

Second, whenever massive blooms of dinoflagellates occur there is most often a human cause, most typically excessive nutrients from anthropogenic pollution.

So the problem, gentle reader, is not in our algae, but in ourselves. On a more positive note, dinoflagellates can exhibit bioluminescence and produce dreamlike scenes of people, boats, or dolphins moving through the water at night creating glowing trails. The dinoflagellates have a more serious role as the symbionts or, zooxanthellae of corals. These eukaryotic phytoplankton species are fascinating in several ways. They are, often beautiful, calcium carbonate platelets borne on the surface of the flagellated unicellular algae.

The exact function of the coccoliths is not understood, but there is experimental evidence that ocean acidification can clearly interfere with normal coccolith production and thus might have adverse effects on these important phytoplankton species.

Another dramatic feature of the coccolithophorids is that they can be very abundant—so abundant in fact that they can turn the surface of the northern Atlantic whitish for miles and miles, and clearly can be seen in satellite photographs.

The abundance of the coccolithophorids can be made dramatically clear when one considers that the flagellated unicells are microscopic—too small to be seen without a good microscope.

If one keeps in mind how tiny the coccoliths are and then considers the white cliffs of Dover and realizes that the chalk of the white cliffs of Dover is largely composed of coccoliths, one realizes that there had to have been billions and billions of coccolithophorids living and dying in the ocean over millions of years to generate such massive accumulations.

It seems appropriate to return to, and conclude with, the prokaryotic blue—green algae, those hardworking photosynthesizers that changed the atmosphere of the planet. Like other prokaryotes the blue—green algae are abundant and present in almost every conceivable habitat from oceans and lakes as expected , to ice, snow, thermal hot springs, and deserts perhaps not as expected. But while we and the blue—greens co-inhabit the planet, we owe them our thanks not only for the oxygen they produce and the vital role they play as primary producers in the food webs, but also for nitrogen fixation.

Our atmosphere is filled with nitrogen and this inert gas prevents the oxygen in our atmosphere from igniting when we strike a match when the first nuclear bomb test was planned there could have been at least a bit of concern that the buffering effects of nitrogen would not suffice and the whole planet might have gone up in flame but luckily that was not the case!

Living organisms must have nitrogen hence millions of dollars spent on nitrogen-rich fertilizers around the world , but not in the form of the inert gas two nitrogen atoms tightly bound by three covalent bonds. This occurs when parts of a plant break off and develop directly into new individuals. All offspring resulting from asexual reproduction are clones; they are genetically identical to each other and the parent seaweed.

Carrageean products. Agar plates. Seaweeds area food source for humans especially in East Asia, it is most commonly associated with Japanese food. Seaweeds also are used to make a number of food additives such as alginates and carrageenan which is used in cooking and baking as a vegetarian alternative to gelatine.

Many seaweeds are used as medicine. Alginates are used in wound dressings and in the production of dental moulds and agar is used very widely in Microbiology to help grow bacterial cultures.

Seaweeds are ingredients in toothpaste, cosmetics and paints and are used in industrial products such as paper coatings, adhesives, dyes, gels, explosives and many more. Much of the oil and natural gas we use today formed from seaweeds which partially decomposed on the sea floor many millions of years ago. Japanese food uses seaweeds extensively - Kombu a brown alga and Kim nori a red alga. Join Scripps' Institution's Russell Chapman as he discusses the important roles algae have played in the development of life as we know it.

Thanks to I would sincerely like to thank the many members of the Flickr community who have given me permission to use their wonderful images for this unit. Their contributions really make this unit come alive!

Next: Brown Algae Marine Algae Seaweed is a term applied to multicellular, marine algae which are large enough to be seen by the eye unaided. Some can grow to up to 60 metres in length. Seaweeds include members of the red, brown and green algae. They are members of the kingdom Protista meaning they are not Plants. They do not have the vascular system internal transport system of plants and do not have roots, stems, leaves and flowers or cones. Like plants they use the pigment chlorophyll for photosynthesis but also contain other pigments which may be coloured red, blue, brown or gold.