by Samantha Law, Curator, NCIMB
25 June is the UNESCO International Day for the Conservation of the Mangrove Ecosystem. So why do mangrove ecosystems merit a special day? Mangroves are intertidal forests that exist along tropical and subtropical coasts. UNESCO state that they support a rich biodiversity and provide a valuable nursery habitat for fish and crustaceans. They act as a form of natural coastal defence against storm surges, tsunamis, rising sea levels and erosion, and their soils are highly effective carbon sinks, sequestering vast amounts of carbon. In other words, in addition to providing an important habitat for many species of animals they have a key role in mitigating the impacts of climate change. These coastal carbon sinks, sometimes referred to as “coastal blue carbon” can lock away accumulated carbon for thousands of years.
However, it has been estimated that more than three-quarters of the world’s mangroves are under threat along with all the aquatic and terrestrial organisms that depend on them.
So why am I, as a microbiologist, highlighting this particular UNESCO day? When thinking about ecosystems and biodiversity, many people focus on the higher order organisms – plants, and animals. Of course, these are highly valuable parts of the ecosystem, which should definitely be protected, but it is imperative that we also consider the importance of microbial biodiversity, as all other life depends on it. Mangrove ecosystems are an excellent illustration of the importance of microbial biodiversity because microorganisms make key contributions to the productivity and carbon budget of mangroves.
Microbiologists have been studying the mangrove microbiome for many years, and recently, understanding of these precious communities will have benefited greatly from the increased availability of next generation sequencing technology – allowing researchers to “see” the extent to microbial biodiversity much more easily. An example of a program with a focus on the microbiology of Mangroves is The Mangrove Microbiome Initiative, which was formed by an international network of researchers with the aim of advancing mangrove microbiome research, and in a paper introducing the initiative, the authors highlight the role of mangrove microbiome research in opening up opportunities for microorganisms-mediated approaches to mangrove protection and rehabilitation. It is clear that Microbiological research, and an in-depth understanding of the mangrove microbiome, has an important role to play in managing and protecting mangroves for the future.
Culture collections like the National Collection of Industrial, Food and Marine Bacteria play an important role in preserving microbial diversity for generations to come, and our culture collection includes a number of strains that have been isolated from mangroves.
Depositing strains in culture collections makes them available to other researchers working on similar programmes, but there could be additional benefits to society. Environmental microorganisms can be a rich resource for biotechnology. For example, two of the strains listed below are Streptomyces species – a genus well known for the production of antimicrobials.
NCIMB strains isolated from Mangroves
| NCIMB number | Taxon | Isolated from |
| NCIMB 1447 | Saprospira grandis | Beach mud among mangroves, Galapagos Islands |
| NCIMB 13602 | Microbacterium halophilum | Soil in mangrove rhizosphere |
| NCIMB 13604 | Microbacterium thalassium | Soil in mangrove rhizosphere, Iriomote island |
| NCIMB 13882 | Agromyces luteolus | Soil of rhizosphere of mangrove, Sonneratia alba, in the estuary of the Shiira River in Iriomote Island, Japan |
| NCIMB 13881 | Agromyces bracchium | Soil of rhizosphere of mangrove, Bruguera gymnorrhiza, in the estuary of the Shiira River in Iriomote island, Japan |
| NCIMB 14577 | Microbulbifer chitinilyticus sp. nov. | Mangrove area sediment, Okanawa, Japan |
| NCIMB 14576 | Microbulbifer okinawensis sp. nov. | Mangrove soil sediment, Sanya, China |
| NCIMB 14820 | Streptomyces sanyensis | Mangrove soil sediment, Sanya, China |
| NCIMB 14980 | Streptomyces mangrovicola | Sediment of Avicennia marina, mangrove plant from Wadi el Gemal, Red Sea, Egypt |
| NCIMB 15550 | Halobacillus mangrovi | Leaf surface of black mangrove, Avicennia germinans |
Further reading
https://www.unesco.org/en/days/mangrove-ecosystem-conservation
https://doi.org/10.1128/msystems.00658-20
https://oceanservice.noaa.gov/ecosystems/coastal-blue-carbon
https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.65008-0
“Microorganisms make key contributions to the productivity and carbon budget of mangroves”