Lyngbya Aestuarii Research Articles

The bio‐control potential of Alcaligenes aquatilis against its associated cyanobacteria Lyngbya aestuarii

AbstractCyanobacteria and heterotrophic bacteria show many similarities in their structure but are different based on their nutritional habits. Autotrophic cyanobacteria and heterotrophic bacteria coexist closely in their natural environments and are capable of a variety of interactions (synergistic, neutral, and antagonistic) due to the secretion of growth‐promoting/retarding (toxin) substances by the bacterial partner. In this study, the cyanobacteria Lyngbya aestuarii and its associated bacteria Alcaligenes aquatilis isolated from the mangrove water of Bhitarkanika showed an antagonistic interaction. The growth of axenic and co‐cultured (1:1; cyanobacteria to bacteria) cyanobacteria was examined under photoautotrophic conditions, to evaluate the interactions between the two groups. The bacteria were found to have cellulase and protease activity and were able to obstruct the growth of cyanobacteria under co‐culture conditions. Besides that, the bacteria secrete many allelochemicals like phenol, tannin, amino acids (alanine and aspartic acid), and hydroxamate siderophore to its surroundings which inhibit the growth and metabolism of the cyanobacteria under co‐cultured conditions. Findings from this study indicate its possible application for wastewater management.

Видовий склад водоростей солоних приморських водойм Приазовського національного природного парку

The paper is devoted to the researches of species composition and taxonomic structure of algae in the saline coastal reservoirs of the Pryazov National Natural Park (PNNP). It is established that species composition of algae in the studied reservoirs under modern conditions includes 153 species. These species represented 7 divisions, 11 classes, 32 orders, 61 families, 92 genera. The highest species richness at the level of divisions showed Cyanoprokaryota (43.8% of the total number of species), Bacillariophyta (32.0%) and Chlorophyta (20.9%). These divisions include 148 species and form the basis of the species composition in the studied water bodies. The leading orders of algae in the researched reservoirs were Oscillatoriales and Synechococcales (23 and 20 species respectively). The most diversely represented families were: Oscillatoriaceae (13 species), Nostocaceae, Leptolyngbyaceae, Naviculaceae (8 each), Microcoleaceae, Bacillariaceae (7 each). The top list of the genera by this parameter: Leptolyngbya (6 species), Lyngbya, Nostoc, Phormidium, Nitzschia (5 each), Calothrix, Kamptonema, Cocconeis, Navicula (4each).The highest frequency of occurrence among the identified species had also diatoms, cyanoprokaryotes and green algae: Halamphora coffeiformis (5.26%), Lyngbya aestuarii (4.21%), Cladophora siwaschensis (3.51%), Hantzschia amphioxys (3.33%), Nodularia harveyana (2.98%).Our researches demonstrate that species composition of algae of the studied saline coastal reservoirs of PNNP is quite impoverished in comparison with the partial soil algae flora, as well as the species list of algae of the freshwater reservoirs and seas of Ukraine. Specific features of the taxonomic composition of the saline coastal reservoirs are manifested in the association of organisms of fresh, marine and terrestrial habitats.

Using Mouteh goldmine soil cyanobacteria for tailing damp soil bioremediation

Introduction: Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. Presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands threatens food security. There are approximately 1 billion ha salt-affected soils all over of world, which can be made available resources after chemical, physical and biological remediation. Existence of many mines in the world and also in Iran and as a result, soil erosion and dust release from waste dams is matter of concern. Bioremediation using biological agents to detoxify and degradation of environmental pollutants- provides a suitable alternative method for substitution of current heavy metals removal strategies. Material and methods: Daily as a result of extraction operations by cyanidation in Mouteh gold mining complex, waste water and waste soil sediment widely achieved. In this study soil samples were collected from Mouteh Goldmine tailing damp soil in September 2018. The collected soil samples were cultured in BG11 medium and incubated for microalgae identification and biomass production. Also 5 gr soil inoculated with 0.5 gr biomass and the physico-chemical characteristics of the soil including pH, Na+ and K+, Pb and Cd, before and after the inoculation of soil with Cyanobacteria were determined.Results and discussion: in this study, cyanobacteria Phormidium tenue Gomont, Osillatoria tenuis C.Agardh ex Gomont, Lyngbya aestuarii Liebman ex Gomont and green Algae, Scenedesmus obliquus (Turpin) Kutzing were identified. Culture results of filamentous cyanobacteria on goldmine tailing damp soil showed that cyanobacteria can grow easily and produced a surface crust significantly. The results of the Physical analysis of the soil samples showed that O. tenuis decreased Na as a salinity element, and P. tenue absorbed high amounts of Pb as a heavy metal pollution element. Probably by using Mouteh Goldmine soil cyanobacteria, Osillatoria tenuis and Phormidium tenue for mine tailingdamp soil bioremediation, could play mine recovery from salinity and heavy metals and also preventing soil erosion and dust release from waste dams.Conclusion: Generally, it can be concluded thatdue to the existence of many goldmines in the word and Iran, daily as a result of extraction operations by cyanidation and high toxicity of cyanide, environmental adverse effects are observed. Dust release from waste dams can be affected health of living organisms like mining workers, plants and even soil microalgae which are close to the mine. By soil goldmine bioremediation can be processed biological resuscitation faster. The research results of African goldmine researchers on soil samples showed that cyanobacteria produced a surface crust significantly, that with the results of this research based on the growth of Phormidium tenue in the mine and producing a surface crust is consistent.

Circadian clock-controlled gene expression in co-cultured, mat-forming cyanobacteria

Natural coastal microbial mat communities are multi-species assemblages that experience fluctuating environmental conditions and are shaped by resource competition as well as by cooperation. Laboratory studies rarely address the natural complexity of microbial communities but are usually limited to homogeneous mono-cultures of key species grown in liquid media. The mat-forming filamentous cyanobacteria Lyngbya aestuarii and Coleofasciculus chthonoplastes were cultured under different conditions to investigate the expression of circadian clock genes and genes that are under their control. The cyanobacteria were grown in liquid medium or on a solid substrate (glass beads) as mono- or as co-cultures under a light–dark regime and subsequently transferred to continuous light. TaqMan-probe based qPCR assays were used to quantify the expression of the circadian clock genes kaiA, kaiB, and kaiC, and of four genes that are under control of the circadian clock: psbA, nifH, ftsZ, and prx. Expression of kaiABC was influenced by co-culturing the cyanobacteria and whether grown in liquid media or on a solid substrate. Free-running (i.e. under continuous light) expression cycle of the circadian clock genes was observed in L. aestuarii but not in C. chthonoplastes. In the former organism, maximum expression of psbA and nifH occurred temporally separated and independent of the light regime, although the peak shifted in time when the culture was transferred to continuous illumination. Although functionally similar, both species of cyanobacteria displayed different 24-h transcriptional patterns in response to the experimental treatments, suggesting that their circadian clocks have adapted to different life strategies adopted by these mat-forming cyanobacteria.

Organomineralization of proto-dolomite by a phototrophic microbial mat extracellular polymeric substances: Control of crystal size and its implication for carbonate depositional systems

Many have postulated that a specific microbial metabolism or the presence of microbes or/and their extracellular polymeric substances (EPS) can lead to the formation of dolomite. Although now there is the consensus that dolomite can be formed in the presence of microorganisms, the exact nature of the involvement of microbes in the dolomite nucleation remains a matter of debate. The focus is now in understanding how microbial mats determine the mineralogy of dolomite. Here we report the effect of the EPS extracted from phototrophic microbial mat isolated from a sabkha in Qatar dominated by cyanobacteria (Lyngbya aestuarii) in the formation of dolomite precursors at 25 °C and 40 °C. Both the temperature and the presence of EPS impact the size and morphology of minerals, promoting spherulitic and dumbbell growth in sulfate free solutions. The formation of proto-dolomite was enhanced by the abundance of carboxylated molecules in EPS which controlled the polymorphism of carbonates. Our study emphasizes the dual importance of organic matter and temperature in dolomite formation and their impact on mineral morphology and chemical composition in sabkhas.

Toxicological investigation of a bloom of the blue – green alga Lyngbya aestuarii in Basra Governorate Southern of Iraq

Toxicological investigation of a bloom of the blue – green alga Lyngbya aestuarii in Basra Governorate Southern of Iraq

ЦИАНОПРОКАРИОТЫ УРОЧИЩА ТУБAЛЬСКИЙ ЛИМАН

<p>Information about species composition of Cyanoprocaryota representatives in the natural boundary of Tubalskyi Estuary within Pryazov National Natural Park is supplemented. Taxonomic structure of identified algae species is given, the data about occurrence of species in different habitats within national park is provided. We present a systematic structure and geographical affinity of discovered algae species. We registered 38 species of cyanoprocaryotic algae of orders: Chroococcales, Oscillatoriales and Nostocales with predominance of Oscillatoriales representatives in different habitats of Tubalskyi Estuary within the areas of Pryazov National Natural Park. The greatest number of algae species had genera <em>Lyngbya, Phormidium, Microcoleus Leptolyngbya</em> – 4 species per each genera. The majority of algae species were the cosmopolitans. <em>Microcoleus tenerrimus</em> was registered in all the studied plots of soil sampling and in the water reservoir of Tubalskyi Estuary. The most abundant and distributed species was <em>Lyngbya aestuarii</em>, which formed the macroscopic growths (cyanobacterial mats).</p>

Polymorphism in <i>Lyngbya notarisii</i> (Meneghini) Wille in culture

Not available. Bangladesh J. Plant Taxon. 22(1): 59–61, 2015 (June)

Powerful fermentative hydrogen evolution of photosynthate in the cyanobacterium Lyngbya aestuarii BL J mediated by a bidirectional hydrogenase.

Cyanobacteria are considered good models for biohydrogen production because they are relatively simple organisms with a demonstrable ability to generate H2 under certain physiological conditions. However, most produce only little H2, revert readily to H2 consumption, and suffer from hydrogenase sensitivity to O2. Strains of the cyanobacteria Lyngbya aestuarii and Microcoleus chthonoplastes obtained from marine intertidal cyanobacterial mats were recently found to display much better H2 production potential. Because of their ecological origin in environments that become quickly anoxic in the dark, we hypothesized that this differential ability may have evolved to serve a role in the fermentation of the photosynthate. Here we show that, when forced to ferment internal substrate, these cyanobacteria display desirable characteristics of physiological H2 production. Among them, the strain L. aestuarii BL J had the fastest specific rates and attained the highest H2 concentrations during fermentation of photosynthate, which proceeded via a mixed acid fermentation pathway to yield acetate, ethanol, lactate, H2, CO2, and pyruvate. Contrary to expectations, the H2 yield per mole of glucose was only average compared to that of other cyanobacteria. Thermodynamic analyses point to the use of electron donors more electronegative than NAD(P)H in Lyngbya hydrogenases as the basis for its strong H2 production ability. In any event, the high specific rates and H2 concentrations coupled with the lack of reversibility of the enzyme, at the expense of internal, photosynthetically generated reductants, makes L. aestuarii BL J and/or its enzymes, a potentially feasible platform for large-scale H2 production.

Coupling algal biomass production and anaerobic digestion: Production assessment of some native temperate and tropical microalgae

Coupling algal biomass production and anaerobic digestion is one of the most promising bioprocesses for economically viable algal production. This study assesses the production rates of some native microalgae growing in media supplemented with algal digestate, urban wastewater or digested sludge. Native microalgal populations isolated from temperate freshwaters (Scenedesmus spp.) and marine ecosystems (Nannochloris spp.) had the highest potential production rates (about 100 mg DW L−1 d−1) with algal digestate at about 20% loading ratio. However, no growth was measured for Nannochloris spp., when the ammonium concentration exceeded 100 mg L−1 although Scenedesmus spp. appeared to be tolerant to higher NH4+ concentrations. Very low production rates, or no growth, were measured when microalgae isolated from high salinity waters (Dunaliella salina, Lyngbya aestuarii) were used, suggesting that populations well adapted to extreme environmental conditions are not suitable candidates for growing on wastewater or anaerobic digestate.

Ecophysiology of the estuarine cyanobacterium Lyngbya aestuarii to varying salinity in vitro

Lyngbya aestuarii, one of the dominant cyanobacterium grows in different salinity gradients of Chilika lagoon. It was isolated in axenic culture and its ecophysiology with response to different concentrations of salinity was studied in vitro to understand its adaptation strategies in the changing salinities of the lagoon. Changes in morphological features of the organism were observed with salinity gradients higher than 28 g/L and lower than 14 g/L salinity. Increase in growth was accompanied by increase of chlorophyll-a, carotenoid and cell protein contents of the organism from 3.5 to 28 g/L. Cellular carbohydrate content was higher with increasing salinity of the medium up to 90 g/L. No detrimental effect on pigment synthesis and macromolecular content of the organism was observed at the salinity level ranging from 7 to 56 g/L salinity. Methanolic extract of L. aestuarii showed prominent absorption at 334 nm in the UV-B region of the spectrum due to mycosporine-like amino acid (MAA) and the quantity of MAA increased with increasing salinity. At 7 g/L salinity 150, 93, 58, 34 and 18 kDa proteins were up-regulated; however, at 14 g/L 37, 26 and 28 kDa proteins and in 0, 3.5 and 90 g/L 122, 32 and 20 kDa proteins were repressed; this shows similarities of salinity-induced protein modifications as observed in higher plants. Super oxide dismutase activity also increased in the cells grown at 56 g/L salinity. We conclude because of having these effective adaptation strategies, L. aestuarii cope very well with the changing salinity in different seasons and grows well in the different sectors of the lagoon.

Cyanobacteria, Lyngbya aestuarii and Aphanothece bullosa as antifungal and antileishmanial drug resources

ObjectiveTo investigate two cyanobacteria isolated from different origins i.e. Lyngbya aestuarii (L. aestuarii) from brackish water and Aphanothece bullosa (A. bullosa) from fresh water paddy fields for antifungal and antileishmanila activity taking Candida albicans and Leishmania donovain as targets. MethodsBiomass of L. aestuarii and A. bullosa were harvested after 40 and 60 d respectively and lyophilized twice in methanol (100%) and redissolved in methanol (5%) for bioassay. Antifungal bioassay was done by agar well diffusion method while antileishmanial, by counting cell numbers and flageller motility observation of promastigotes and amastigotes from L. donovani. Fluconazole and 5% methanol were used as control. ResultsBoth the cyanobacteria were found to be potent source of antifungal activity keeping fluconazole as positive control, however, methanolic crude extract (15 mg/mL) of A. bullosa was found more potent (larger inhibition zone) over that of methanolic crude extract of L. aestuarii. Similarly antileishmanial activity of crude extract (24.0 mg/mL) of A. bullosa was superior over that of methanolic crude extract of L. aestuarii (25.6 mg/mL). ConclusionsAntifungal and antileishmanial drugs are still limited in the market. Screening of microbes possessing antifungal and antileishmanial activity drug is of prime importance. Cyanobacteria are little explored in this context because most of the drugs in human therapy are derived from microorganisms, mainly bacterial, fungal and actinomycetes. Thus in the present study two cyanobacterial strains from different origins showed potent source of antifungal and antileishmanial biomolecules.

Aestuaramides, a Natural Library of Cyanobactin Cyclic Peptides Resulting from Isoprene-Derived Claisen Rearrangements

We report 12 cyanobactin cyclic peptides, the aestuaramides, from the cultivated cyanobacterium Lyngbya aestuarii. We show that aestuaramides are synthesized enzymatically as reverse O-prenylated tyrosine ethers that subsequently undergo a Claisen rearrangement to produce forward C-prenylated tyrosine. These results reveal that a nonenzymatic Claisen rearrangement dictates isoprene regiochemistry in a natural system. They also reveal one of the mechanisms that organisms use to generate structurally diverse compound libraries starting from simple ribosomal peptide pathways (RiPPs).

Comparative genomic analyses of the cyanobacterium, Lyngbya aestuarii BL J, a powerful hydrogen producer

The filamentous, non-heterocystous cyanobacterium Lyngbya aestuarii is an important contributor to marine intertidal microbial mats system worldwide. The recent isolate L. aestuarii BL J, is an unusually powerful hydrogen producer. Here we report a morphological, ultrastructural, and genomic characterization of this strain to set the basis for future systems studies and applications of this organism. The filaments contain circa 17 μm wide trichomes, composed of stacked disk-like short cells (2 μm long), encased in a prominent, laminated exopolysaccharide sheath. Cellular division occurs by transversal centripetal growth of cross-walls, where several rounds of division proceed simultaneously. Filament division occurs by cell self-immolation of one or groups of cells (necridial cells) at the breakage point. Short, sheath-less, motile filaments (hormogonia) are also formed. Morphologically and phylogenetically L. aestuarii belongs to a clade of important cyanobacteria that include members of the marine Trichodesmiun and Hydrocoleum genera, as well as terrestrial Microcoleus vaginatus strains, and alkalyphilic strains of Arthrospira. A draft genome of strain BL J was compared to those of other cyanobacteria in order to ascertain some of its ecological constraints and biotechnological potential. The genome had an average GC content of 41.1%. Of the 6.87 Mb sequenced, 6.44 Mb was present as large contigs (>10,000 bp). It contained 6515 putative protein-encoding genes, of which, 43% encode proteins of known functional role, 26% corresponded to proteins with domain or family assignments, 19.6% encode conserved hypothetical proteins, and 11.3% encode apparently unique hypothetical proteins. The strain's genome reveals its adaptations to a life of exposure to intense solar radiation and desiccation. It likely employs the storage compounds, glycogen, and cyanophycin but no polyhydroxyalkanoates, and can produce the osmolytes, trehalose, and glycine betaine. According to its genome, BL J strain also has the potential to produce a plethora of products of biotechnological interest such as Curacin A, Barbamide, Hemolysin-type calcium-binding toxin, the suncreens scytonemin, and mycosporines, as well as heptadecane and pentadecane alkanes. With respect to hydrogen production, initial comparisons of the genetic architecture and sequence of relevant genes and loci, and a comparative model of protein structure of the NiFe bidirectional hydrogenase, did not reveal conspicuous differences that could explain its unusual hydrogen producing capacity.

Salinity induced synthesis of UV-screening compound scytonemin in the cyanobacterium Lyngbya aestuarii

Lyngbya aestuarii is the dominant cyanobacterium in Chilika lagoon occurring in all the seasons irrespective of variation in the salinity regime ranging from 3 to 28ppt. The organism possess the UV screening scytonemin pigment, which was maximum when grown at 56ppt salinity. Three different forms of scytonemin were detected in L. aestuarii with retention time (RT) 1.76, 2.42 and 2.94min, however, occurrence of these forms was influenced by the salinity. Scytonemin with RT 2.42 was sensitive to higher salinity and its maximum concentration was obtained at 28ppt salinity correlated with the highest salinity level of Chilika. Formation of multilayer colored sheath around the trichome was prominently observed at the salinity of the culture from 28 to 56ppt. But at salinity below 7ppt and also at more than 56ppt salinity degradation of sheath with corresponding decrease in scytonemin was observed.

The biosynthesis of cyanobacterial sunscreen scytonemin in intertidal microbial mat communities

We have examined the biosynthesis and accumulation of cyanobacterial sunscreening pigment scytonemin within intertidal microbial mat communities using a combination of chemical, molecular, and phylogenetic approaches. Both laminated (layered) and nonlaminated mats contained scytonemin, with morphologically distinct mats having different cyanobacterial community compositions. Within laminated microbial mats, regions with and without scytonemin had different dominant oxygenic phototrophs, with scytonemin-producing areas consisting primarily of Lyngbya aestuarii and scytonemin-deficient areas dominated by a eukaryotic alga. The nonlaminated mat was populated by a diverse group of cyanobacteria and did not contain algae. The amplification and phylogenetic assignment of scytonemin biosynthetic gene scyC from laminated mat samples confirmed that the dominant cyanobacterium in these areas, L. aestuarii, is likely responsible for sunscreen production. This study is the first to utilize an understanding of the molecular basis of scytonemin assembly to explore its synthesis and function within natural microbial communities.

THE RELATION BETWEEN N2 FIXATION AND H2 METABOLISM IN THE MARINE FILAMENTOUS NONHETEROCYSTOUS CYANOBACTERIUM LYNGBYA AESTUARII CCY 9616(1).

The marine filamentous nonheterocystous nitrogen-fixing cyanobacterium Lyngbya aestuarii (F. K. Mert.) Liebman ex Gomont CCY 9616 was grown under diazotrophic and nondiazotrophic conditions and under an alternating 16:8 light:dark (L:D) regime. Nitrogenase activity appeared just before the onset of the dark period, reaching its maximum 1-2 h in the dark, subsequently decreasing to zero at the beginning of the following light period. Nitrogenase activity was only detected at low levels of O2 (5%) and when the culture was grown in the absence of combined nitrogen. Quantitative reverse transcriptase-PCR (RT-PCR) analysis of one of the structural genes encoding nitrogenase, nifK, showed that the highest levels of transcription preceded the maximum activity of nitrogenase by 2-4 h. nifK transcription was not completely abolished during the remaining time of the 24 h cycle. Even in the presence of nitrate, when nitrogenase activity was undetectable, nifK was still transcribed. The H2 -uptake activity seemed to follow the nitrogenase, but the transcription of hupL (gene encoding the large subunit of uptake hydrogenase) preceded the nifK transcription. However, H2 -uptake and hupL transcription occurred throughout the 24 h cycle as well as under nondiazotrophic conditions, albeit at much lower levels. The hoxH transcript levels (a structural gene coding for the bidirectional hydrogenase) were similar under diazotrophic or nondiazotrophic conditions but slightly higher during the dark period. All three enzymes investigated are involved in H2 metabolism. It is concluded that the uptake hydrogenase is mainly responsible for H2 uptake. Nevertheless, uptake hydrogenase and nitrogenase do not seem to be coregulated.

Checklist of benthic marine algae and cyanobacteria of northern Portugal

Abstract The northern Portuguese coast is a biogeographic transition zone where many macroalgal species have their distribution limits; it is thus a particularly interesting region for investigating species distribution shifts. An updated and complete list of species for this region is not available in spite of its baseline importance for comparative studies with past and present data. Based on new records, literature references, and herbarium data, we provide an updated checklist of the benthic marine algae of the northern Portuguese coast. This checklist includes 346 species: 26 Cyanobacteria, 200 Rhodophyta, 70 Ochrophyta, and 50 Chlorophyta. From these, 21 species are new records for the Portuguese coast (Lyngbya aestuarii, Lyngbya semiplena, Microcoleus acutirostris, Myxosarcina gloeocapsoides, Aiolocolax pulchella, Antithamnion densum, Antithamnion villosum, Antithamnionella spirographidis, Dasya sessilis, Furcellaria lumbricalis, Neosiphonia harveyi, Porphyrostromium boryanum, Chorda filum, Dictyopteris ambigua, Sphacelaria rigidula, Undaria pinnatifida, Vaucheria coronata, Vaucheria velutina, Ulothrix implexa, Ulva scandinavica, and Umbraulva olivascens) and 33 were recorded for the first time in the north of Portugal. Alien species have increased in number and extended their distribution range over the last 10 years in the study area. Distribution shifts of northern cold water species with southern distribution limit in the north of Portugal were not consistent among species.

Composição dos estromatólitos estratiformes da lagoa Salgada, Rio de Janeiro, Brasil

Lagoa Salgada is situated in the north coast of State of Rio de Janeiro, between the districts of Campos dos Goitacazes and São João da Barra, some 41º00'30" W and 21º54'10"S. In the margins of the lagoon the presence of recent stromatolitic constructions was verified. The stromatolite may be defined as lithifying biosedimentary structure, growing through of sediment blade trapping by the carbonate precipitation as result of microbian organism activity. The aim of this study was to characterize the cyanobacteria assemblage in stratiform stromatolites found on the floor of lagoa Salgada. Within the stratiform stromatolites 21 species of cyanobacteria were found, Microcoleus chthonoplastes (Thuret) Gomont 1892 and Lyngbya aestuarii (Liebman) Gomont 1892 are frequent in these stromatolites. The presence of calcite was observed in the stratiform stromatolites. The filamentous cyanobacteria are responsible for the union and imprisonment of sediment to form the layers in the stromatolites. The skeleton remains of mollusks, foraminifers and ostracod found in the area, work as a source of calcium carbonate and of sediment to structure the stromatolites

Lipid biomarkers, pigments and cyanobacterial diversity of microbial mats across intertidal flats of the arid coast of the Arabian Gulf (Abu Dhabi, UAE)

Variations in morphology, fatty acids, pigments and cyanobacterial community composition were studied in microbial mats across intertidal flats of the arid Arabian Gulf coast. These mats experience combined extreme conditions of salinity, temperature, UV radiation and desiccation depending on their tidal position. Different mat forms were observed depending on the topology of the coast and location. The mats contained 63 fatty acids in different proportions. The increased amounts of unsaturated fatty acids (12-39%) and the trans/cis ratio (0.6-1.6%) of the cyanobacterial fatty acid n-18:1omega9 in the higher tidal mats suggested an adaptation of the mat microorganisms to environmental stress. Chlorophyll a concentrations suggested lower cyanobacterial abundance in the higher than in the lower intertidal mats. Scytonemin concentrations were dependent on the increase in solar irradiation, salinity and desiccation. The mats showed richness in cyanobacterial species, with Microcoleus chthonoplastes and Lyngbya aestuarii morphotypes as the dominant cyanobacteria. Denaturing gradient gel electrophoresis patterns suggested shifts in the cyanobacterial community dependent on drainage efficiency and salinity from lower to higher tidal zones. We conclude that the topology of the coast and the variable extreme environmental conditions across the tidal flat determine the distribution of microbial mats as well as the presence or absence of different microorganisms.