Bacterial Communities on and Inside Marine Seaweeds: Distribution and Functions

Jenn Hoskins
7th August, 2024

Bacterial Communities on and Inside Marine Seaweeds: Distribution and Functions

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Alexandria University studied bacteria on ten common seaweeds along the Mediterranean Sea coast in Alexandria
  • Bacteria on seaweeds showed diverse enzyme activities, helping break down complex materials
  • Adding algal extracts increased bacterial populations, showing the strong relationship between bacteria and algae
The marine environment is a complex ecosystem teeming with diverse life forms. Seaweeds, or marine macroalgae, are an essential component of this ecosystem, and their growth and health are heavily influenced by bacteria that inhabit their surfaces. This recent study by researchers at Alexandria University[1] aimed to identify the bacterial populations associated with ten common marine macroalgae along the Mediterranean Sea coast in Alexandria. The study focused on understanding the distribution and functional roles of these bacteria, which can be categorized as either epiphytic (living on the surface) or endophytic (living inside the algae). The researchers examined the effects of different algal habitats on the bacterial populations, categorizing them based on various phenotypic characteristics such as shape, color, mucoid nature, Gram stain type, and spore generation capability. They also assessed the physiological traits of these bacteria to determine the optimal environmental conditions for their association with algae. One significant finding of the study was the wide range of enzyme activities exhibited by the bacterial isolates. Enzymes such as cellulase, alginase, and caseinase were prevalent, indicating the bacteria's role in breaking down complex organic materials. Interestingly, 26% of the isolates showed amylolytic activity, which is the ability to break down starch. However, some isolates from specific sites like Miami, Eastern Harbor, and Montaza lacked catalase activity, an enzyme that helps break down hydrogen peroxide, suggesting site-specific functional variations. Geographical variations and the addition of algal extracts significantly influenced the bacterial populations. For instance, the number of endophytic bacteria associated with green algae increased across all sites, while those associated with red algae showed site-specific changes. The addition of algal extract led to a ninefold increase in the number of epiphytic bacteria on Cladophora pellucida in Montaza. This highlights the intricate relationship between bacterial populations and their algal hosts, influenced by both geographical location and the presence of algal extracts. The study's findings align with earlier research on the interactions between algae and bacteria. For instance, a study on the interrelations between epiphytic bacteria and macroalgae[2] found that seaweed-associated bacterial communities are influenced by algal organic exudates and elemental deposits on their surfaces. This triggers chemotaxis responses from bacteria, enabling them to metabolize these substrates. The current study by Alexandria University expands on these findings by providing a detailed phenotypic and physiological characterization of these bacterial communities, further elucidating their functional roles. Additionally, previous research on algae-based wastewater treatment[3] highlighted the importance of maintaining a diverse microalgal consortium for biofuel production. The current study's focus on bacterial diversity and enzyme activity could have implications for optimizing algal growth in such systems, potentially enhancing the efficiency of biofuel production. The impact of sedimentation on seagrass leaves[4] also provides a relevant context. The study found that fine sediment particles negatively affect seagrass by impeding gas exchange and reducing internal aeration. Similarly, the current study suggests that environmental factors, including geographical variations and the presence of algal extracts, significantly influence bacterial populations associated with algae. This underscores the importance of understanding these interactions to mitigate potential negative impacts on marine ecosystems. In conclusion, the study by Alexandria University provides valuable insights into the complex interactions between marine macroalgae and their associated bacterial communities. By identifying the phenotypic and physiological traits of these bacteria, the researchers have advanced our understanding of their functional roles and the environmental factors that influence their distribution. These findings have broader implications for marine ecology, wastewater treatment, and biofuel production, highlighting the importance of maintaining diverse and functional microbial communities in marine environments.

BiochemEcologyMarine Biology

References

Main Study

1) Distribution and functional perspective analysis of epiphytic and endophytic bacterial communities associated with marine seaweeds, Alexandria shores, Egypt

Published 6th August, 2024

https://doi.org/10.1186/s12866-024-03426-x

Related Studies

2) Distribution, Interaction and Functional Profiles of Epiphytic Bacterial Communities from the Rocky Intertidal Seaweeds, South Africa.

https://doi.org/10.1038/s41598-019-56269-2

3) Organic carbon, influent microbial diversity and temperature strongly influence algal diversity and biomass in raceway ponds treating raw municipal wastewater.

https://doi.org/10.1016/j.biortech.2015.02.013

4) Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion.

https://doi.org/10.3389/fpls.2017.00657


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