Zebra mussel holobionts fix and recycle nitrogen

News   •   January 5, 2021

Zebra mussels (Dreissena polymorpha) are filter-feeding bivalves native to the Ponto-Caspian region, which successfully invaded several regions in Europe and North America, where they significantly altered community structure and ecosystem functioning. Through their proficient filter-feeding and reproduction, these organisms can colonize diverse habitats causing severe ecological and economic disruption, damaging harbors and waterways, ships and boats, and water-treatment and power plants (see below).

While previous work suggested that invasion by zebra mussels can indirectly alter microbial communities and Nitrogen transformations at the seafloor, the direct role of the mussel microbiome remained largely unexplored both in terms of metabolic repertoire and magnitude of the Nitrogen transformations.

In this research, carried out within the frame of the INBALANCE project, we assessed the impact of zebra mussels on Nitrogen processes in laboratory incubations designed to discern the impact of the microbiome and to quantitatively assess their relevance at the benthic scale, concurrently identifying potential microbial players.

For the first time, we report that zebra mussel holobionts not only contribute to Nitrogen recycle and loss via DNRA and denitrification, but also to Nitrogen fixation, promoted by a microbial community substantially different from that of the water column, which suggests a unique niche for N2 fixation associated with the mussels.

The capacity to host N2-fixing bacteria may facilitate zebra mussels in their establishment and spread in nutrient-poor environments, and might represent an important factor in determining their high invasiveness and adaptive potential.

Here is the link to the original publication, which was published in the journal Frontiers in Microbiology.