Cyanobacteria in mangrove ecosystems

Abstract

Mangroves are subject to the effects of tides and fluctuations in environmental conditions, which may reach extreme conditions. These ecosystems are severely threatened by human activities despite their ecological importance. Although mangroves are characterized by a highly specialized but low plant diversity in comparison to most other tropical ecosystems, they support a diverse microbial community. Adapted microorganisms in soil, water, and on plant surfaces perform fundamental roles in nutrient cycling, especially nitrogen and phosphorus. Cyanobacteria contribute to carbon and nitrogen fixation and their cells act as phosphorus storages in ecosystems with extreme or oligotrophic environmental conditions such as those found in mangroves. As the high plant productivity in mangroves is only possible due to interactions with microorganisms, cyanobacteria may contribute to these ecosystems by providing fixed nitrogen, carbon, and herbivory-defense molecules, xenobiotic biosorption and bioremediation, and secreting plant growth-promoting substances. In addition to water, cyanobacterial colonies have been detected on sediments, rocks, decaying wood, underground and aerial roots, trunks, and leaves. Some mangrove cyanobacteria were also found in association to algae or seagrasses. Few studies on mangrove cyanobacteria are available, but together they have reported a substantial number of species in these ecosystems. However, the cyanobacterial diversity in this biome has been traditionally underestimated. Though mangrove communities generally host cyanobacterial taxa commonly found in marine environments, unique microhabitats found in mangroves Communicated by Anurag chaurasia.

New Benthic Cyanobacteria from Guadeloupe Mangroves as Producers of Antimicrobials

“…Cyanobacteria are among the important primary producers in various coastal ecosystems including mangroves. Besides their occurrence in the bacterioplankton, various cyanobacteria occur in biofilms on the sediment surface, on rocks, and on biological surfaces as part of the periphyton [1,2]. Biofilm-forming cyanobacteria contribute to locale trophic networks through carbon fixation, and depending on species also to nitrogen fixation, accumulation of calcium, magnesium, and phosphorous [3].…”

“…Biofilm-forming cyanobacteria contribute to locale trophic networks through carbon fixation, and depending on species also to nitrogen fixation, accumulation of calcium, magnesium, and phosphorous [3]. The benthic species, especially in tropical zones, may form dense biofilms on various types of substrates and may have major ecological roles [2] but are still poorly known, compared to pelagic species. Although cyanobacteria are of particular interest as ecologically-relevant microorganisms, they are also regarded as producers of a broad diversity of bioactive secondary metabolites including cyanotoxins and various antimicrobial compounds which influence their interactions with other organisms [1,4,5].…”

“…Currently, the 1700 described cyanobacterial species [7] are probably only a small subset of the group's true diversity. The tropical regions and the benthic compartment are particularly ill-explored compared to the potential diversity their harbor [2]. Chemical investigations have focused on an even smaller subset of this diversity, with over 50% of characterized metabolites reported from the order Oscillatoriales, and 35% in the sole genus Lyngbya [5].…”

Cyanobacterial biodiversity and associated ecosystem services: introduction to the special issue

“…Cyanobacteria can survive in certain extreme environments, and the biodiversity of those surviving in hypersaline environments, their adaptative mechanisms, and contribution to ecosystem maintenance, is reviewed by Oren (2015). The cyanobacterial biodiversity of mangrove ecosystems, with extreme or oligotrophic environmental conditions, has a significant ecological role, especially in term of C and N fixation and P accumulation, discussed by Alvarenga et al (2015). Polar regions (Antarctica and the arctic) are well known for extreme environmental conditions which are too harsh for the survival of most life.…”

Phyllonema aviceniicola gen. nov., sp. nov. and Foliisarcina bertiogensis gen. nov., sp. nov., epiphyllic cyanobacteria associated with Avicennia schaueriana leaves

“…Mangroves host several cyanobacteria with important ecological roles, including a considerable number of undescribed taxa (for a review, see Alvarenga et al, 2015). A study using culture-independent methods to assess the diversity of cyanobacteria inhabiting leaf surfaces of mangrove trees observed the phyllosphere of Avicennia schaueriana was colonized by a unique cyanobacterial community (Rigonato et al, 2012).…”