The ocean floor is a graveyard of more than three million shipwrecks, most of which are made of wood. Although they change the microbial habitat of the seafloor, new research has shown that the impacts are not all bad and that they can even increase productivity.
“Microbial communities are important to know and understand because they provide early and clear evidence of how human activities are changing ocean life,” said author Dr. Leila Hamdan of the University of Southern Mississippi, USA.
A study of microbial life around two 19eCentury shipwrecks in the Gulf of Mexico explore the diversity of these man-made habitats. Samples of biofilms were collected using pieces of pine and oak placed near the shipwreck and up to 200 meters from the shipwreck. After the fourth month, microbes were measured using gene sequencing, including all bacteria, archaea and fungi
“Ocean scientists know that natural hard habitats, some of which have been around for hundreds to thousands of years, determine the biodiversity of life on the seafloor,” Hamdan says. “This work is the first to show that built habitats (places or things man-made or modified) also affect the films of microbes (biofilms) that cover these surfaces. These biofilms ultimately allow hard habitats to change. in islands of biodiversity.”
The results showed that bacteria preferred oak over pine, but the wood species had less of an impact on archaea or fungal diversity. The diversity also varied depending on the proximity of the wreck site, where surprisingly the greatest diversity was not at the wreck site but peaked 125 meters away. The depth of the water and proximity to a food source such as the Mississippi River delta also played a role in the spread of biofilms.
While this study provides information on wooden shipwrecks and the impact on microbial diversity, there are also thousands of oil and gas platforms and oil pipelines in the Gulf of Mexico alone that warrant further research to understand their microbial effects as well.
“While we are aware that human impacts on the seafloor are increasing through the multiple economic uses, the scientific discovery is not keeping pace with how this shapes the biology and chemistry of natural undersea landscapes,” Hamdan said. “We hope this work will spark a dialogue leading to research into how built habitats are already changing the deep sea.”
Read more about this research published in Frontiers in Marine Science†
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