Description

The problem and current solutions

The quagga mussel (Dreissena bugensis) is a species of freshwater mussel originally coming from the Black Sea in Ukraine. The origin of the quagga mussel remains elusive, but several studies suggest that this bivalve is native to the Dnieper basin (Son, 2007). Like the zebra mussel, the quagga mussel is a very aggressive invasive species in terms of invasiveness (Figure 1). These two species of mussels are similar both from a morphological and ecological point of view. However, many characteristics allow the quagga mussel to dominate the zebra mussel. Indeed, quagga mussels can reproduce from 5°C, so they can reproduce almost all year round. (MFFP, s. d.) (Figure 2A). The first quagga mussel invasion in Switzerland was observed in Lake Constance in 2016. As shown in Figure 2, observations made between 2010 and 2015 show the presence of larvae only in summer. From 2016, we can see a year-round presence. This propagation of the mussels is due to the lake's ideal temperatures and the water current that allows the larvae to drift. In addition, the quagga mussels can tolerate a drop in food resources and cold temperatures, thus facilitating them to colonize at great depths, unlike the zebra mussel. Furthermore, its high tolerance to cold temperatures allows the quagga mussel to reach great depths. For example, in Lake Constance, Dreissena bugensis larvae can be found at depths of more than 100 m (Figure 2B). As seen in Figure 3, in 1971, the larvae were mainly present between 0 and 10 m deep. However, in 2018 the researchers noticed that the larvae are mainly between 10 and 20 m and are found up to a depth of 100 m (IGKB, 2019).

Zebra and Quagga mussel
Figure 1 : Image of a zebra mussel (Dreissena polymorpha), left, and of a quagga mussel (Dreissena bugensis), right. The main characteristics of the zebra mussel are a presence of zigzag patterns, a triangular shape and a shell that can lie flat. On the contrary, the quagga mussel has a round shape and cannot lie flat. However, it should be noted that the genus Dreissena varies in appearance from one individual to another.

Apart from these characteristics, quagga mussels have a rapid growth, a short reproduction cycle, a great capacity for propagation, and a phenotypic plasticity that allows them to adapt to different environments and a generalist diet. For example, quagga mussels can eat rotifers, diatoms, and cladocerans, which are easily found in freshwater lakes. Its great capacity for dispersal and its ability to adapt to different environments has allowed it to colonize almost all of Europe and the United States of America. This colonization was made possible by unintentional introductions during transport to non-native areas. By clinging to fishing nets or the hulls of boats (professional or leisure), the quagga mussel enters and survives transport routes. Subsequently, it can establish itself locally by reproducing and increasing its numbers.

Zebra and Quagga mussel
Figure 2 : A) Abundance of Dreissene larvae at the Fischbach-Uttwil station at a depth between 0 and 100m. B) Comparison between Lake Constance samples from 1971 and 2018 illustrating the difference in depth distribution of Dreissene larvae (IGKB, 2019).

The expansion of the quagga mussels began in the 1940s in Russia and eventually spread throughout Europe and North America at the end of the 20th century. Its first appearance in Switzerland was in 2014 when it invaded the Rhine near Basel, and currently, quagga mussels can be found in over six Swiss lakes, particularly in Lake Geneva, Lake Constance, and Lake Neuchâtel (Figure 3).

Zebra and Quagga mussel
Figure 3: Current distribution of the quagga mussel (Dreissena bugensis) in Switzerland since its first observation in the Rhine, near Basel, in 2014. Black dots represent the registered presence of quagga mussels, open squares stand for the regions where quagga have not yet been found, and the first observation of eDNA (environmental DNA) is represented by a star (Haltiner, 2022).

The unintentional introductions of quagga mussels have caused many problems from an economic and environmental point of view. Their impacts on aquatic environments are numerous. The large filtration capacity of the mussel, up to 1 L of water per day, allows it to filter a great number of suspended particles and phytoplankton, which causes a decline of the latter and an increase in water transparency. Water transparency results in an over-proliferation of algae during the day, leading to a drastic decrease in oxygen concentration in freshwater and negatively impacting biodiversity (CNRS, s. d.). In conclusion, quagga mussels alter the food chain by reducing food resources and modifying the communities of freshwater species (OBJAV, 2016).

Beyond the environmental impacts, the quagga mussel causes economic disasters. The uncontrolled proliferation of the bivalve leads to increased maintenance work and associated costs. For example, the Metropolitan Water District of Southern California (MWD) will spend between $10 million and $15 million annually to control quagga mussel infection (Chakraborti et al., 2016). The proliferation of quagga mussels can completely obstruct hydraulic systems and pipes for water collection or colonize boat hulls. When water pipes become blocked, they require daily maintenance to keep them in working order (Figure 4). Figure 4 shows a diagram of a typical potable water distribution system. Mussels can travel great distances before colonizing a spot in the pump system. Thus, colonies of mussels can be found in different places throughout the system (Chakraborti et al., 2016). In the US, the costs generated by the quagga mussels amount to approximately 1 billion dollars per year. In Switzerland, the cost of mussel management reaches several million Swiss francs (CHF). For instance, the wastewater treatment plant of Saint-Sulpice (STEP) spent an additional 10 million CHF for this (Cluster Eau Lémanique, s. d.). To protect its drinking water network against quagga mussels, the City of Lausanne is investing in another 11 million CHF. These sums are only set to increase dramatically as quagga mussels continue to invade more Swiss lakes.

Zebra and Quagga mussel
Figure 4 : Schematic representation of a typical drinking water distribution system (Chakraborti et al. 2016, p. E444).

Current solutions consist of cleaning the pipes by hand, using activated carbon, or using chlorine and other chemicals which can be toxic to other organisms. The available solutions also include awareness campaigns or an obligation to clean boats previously used in another body of water. As these methods are costly or environmentally unacceptable as long-term solutions, we aim to find a biobased solution to control invasive species populations.

Note: During the mussel collection, we saw that many small shrimps lived hidden under the shells. We discussed it with the co-director and he told us that these shrimps are the Hemimysis anomala, an invasive species that profit from the presence of quagga mussels to have a habitat.

Our project

Due to its impact on biodiversity and the economy, the iGEM team of the University of Lausanne decided to tackle this problem and make it our mission. Our goal is to find a solution to this local, as well as global, problem by working hand in hand with professionals and people affected by this invasive species.

To do this, our project, named “Quagg’out”, is divided into two parts both based on the genetic engineering of the bacteria Escherichia coli and Pseudomonas protegens. First, we set out to kill the mussels using the FitD toxin. Encoded by the fitD gene, this toxin naturally expressed by the bacterium Pseudomonas protegens is known for its insecticidal properties as well as its potency as a molluscicidal agent. Second, we wish to prevent the attachment of mussels to surfaces using zosteric acid, which has anti-adhesive properties. Zosteric acid is an acid naturally produced by the algae Zostera marina and possesses anti-insecticidal, anti-fungal, and anti-adhesive properties (Jendresen & Nielsen, 2019).

References

  1. Benson, A. (2022, 19 juillet). Quagga mussel (Dreissena rostriformis bugensis). Nonindigenous Aquatic Species.https://nas.er.usgs.gov/queries/factsheet.aspx?speciesid=95
  2. Chakraborti, R. K., Madon, S., & Kaur, J. (2016). Costs for Controlling Dreissenid Mussels Affecting Drinking Water Infrastructure : Case Studies. Journal - American Water Works Association, 108, E442—E453. https://doi.org/10.5942/jawwa.2016.108.0104
  3. Ecosysteme aquatique : eutrophisation. (s. d.). Centre national de la recherche scientifique.https://www.cnrs.fr/cw/dossiers/doseau/decouv/ecosys/eutrophisat.html
  4. Haltiner, L. (2022). The distribution and spread of quagga mussels in perialpine lakes north of the Alps. Aquatic Invasions, 17(2). https://doi.org/10.3391/ai.2022.17.2.02
  5. IGKB. (s. d.). Internationale Gewässerschutzkommission - Start. https://www.igkb.org
  6. Invasive quagga mussel could profoundly change Swiss lakes. (2022, 24 mars). SWI swissinfo.ch. https://www.swissinfo.ch/eng/sci-tech/invasive-quagga-mussel-could-profoundly-change-swiss-lakes/47459450
  7. La moule exotique quagga se répand en Suisse et impacte les écosystèmes lacustres. (2022, 24 mars). Confédération Suisse. https://www.admin.ch/gov/fr/accueil/documentation/communiques.msg-id-87721.html
  8. La moule quagga. (s. d.). Ministère des Forêts, de la Faune et des Parcs. https://mffp.gouv.qc.ca/la-faune/especes/envahissantes/moule-quagga/
  9. L'eutrophisation - OBVAJ. (2016, 18 juillet). OBVAJ. https://obvaj.org/citoyens/les-bonnes-pratiques/eutrophisation/
  10. Radio Télévision Suisse. (2021a, 10 avril). Dans le Léman, la moule quagga est un casse-tête pour les services des eaux. rts.ch. https://www.rts.ch/info/regions/vaud/12111430-dans-le-leman-la-moule-quagga-est-un-cassetete-pour-les-services-des-eaux.html
  11. Rees, D. J. (2014). The Quagga Mussel (Dreisenna Bugensis) Byssus : A Proteomics Approach to Investigate Underwater Attachment Proteins in a Freshwater Mussel[Thesis for the degree of Master of Applied Science non publiée]. University of Toronto.
  12. Retour d’expérience : Moule Quagga | Cluster Eau Lémanique - Evian. (s. d.). Cluster Eau Lémanique. https://clustereau.fr/axes/eau-biodiversite/retour-dexperience-moule-quagga/
  13. Sennhauser, F. (2022, 7 mai). Déjà présente dans le Léman – La moule quagga inquiète aussi à Zurich. Tribune de Genève.https://www.tdg.ch/des-moules-invasives-inquietent-zurich-418999457655
  14. Son, M. (2007). Native range of the zebra mussel and quagga mussel and new data on their invasions within the Ponto-Caspian Region. Aquatic Invasions, 2(3), 174–184. https://doi.org/10.3391/ai.2007.2.3.4
  15. Zhulidov, A., Kozhara, A., Nalepa, T., Gurtovaya, T., & Zhulidov, D. (2013). Relative abundance of two dreissenid species, Dreissena polymorpha and Dreissena rostriformis bugensis in the Lower Don River system, Russia. Aquatic Invasions, 8(3), 311–318.