The Problem
The invasion of non-native macroalgal species is a growing concern for coastal ecosystems as it poses a threat to their biodiversity, function, and services. Due to an increase in global trade, the rate of introduction of these species has risen, leading to more efforts to monitor and detect them. About 80% of orders within the macroalgal phyla Chlorophyta, Rhodophyta, and Phaeophyceae have invasive species, and the potential number of these species exceeds 300. Various activities, such as transoceanic shipping and aquaculture, can introduce macroalgae into new ecosystems. Invasive macroalgae can negatively affect ecosystems as they can tolerate various abiotic conditions and outcompete native species for growing substrate and nutrient resources due to their higher growth rates. Besides the issues of outcompeting and ecosystemic disruption, these invasive microalgae cause harm through secondary metabolites. These metabolites, although not present in all invasive algae, serve as a defense against other creatures and have been proven to directly inhibit the growth and survival of other marine life. Mainly, invasive macroalgae can directly harm ecosystems through the process of bloom formation and eventual decay. This can release toxic sulfides and the accumulation of CO2 further harming the environment. Dasysiphonia Japonica, native to the western Pacific Ocean, has invasively spread throughout the Atlantic during the past 40 years. The algae have spread across Europe and were first reported in the western Atlantic in 2007 on Rhode Island, and have since spread throughout the Long Island Sound. D. Japonica biomass has decreased the survival of all juvenile and larval marine life. Once exposed to extensive concentrations, larval M. Beryllina experienced complete mortality (0% survival) and smaller juvenile M. Menida experienced a 50% survival rate. The decay also reduces pH and DO (dissolved oxygen) levels. Collectively, the study determined that this red seaweed invasion into the east coast may directly harm commercially and ecologically important indigenous marine life.
