Editorial: Macroalgal blooms in a global change context

Abstract

Editorial on the Research Topic Macroalgal blooms in a global change contextFollowing the Second World War, the development of industrial agriculture and medical advances allowed for an exponential increase in the human population. During this period, the concept of mass consumption society was also encouraged in developed and developing countries, increasing the demand for resources (Cherubini et al., 2018;Gaulin and Le Billon, 2020;Elmqvist et al., 2021). The associated expansion and intensification of human activities necessary to cover the needs of a larger and more demanding population led to important changes in the earth system, making humankind one of the most important drivers of global change (e.g., ocean acidification, climate change, eutrophication, biological invasions). All of these human-induced changes in environmental conditions have produced important alterations and imbalances in the structure and functioning of ecosystems, especially in aquatic systems (Lotze et al., 2006;James et al., 2023).In coastal and estuarine waters, one of the most evident signs of the impact of human activities is the development of macroalgal blooms. Macroalgal blooms are accumulations of fast-growing opportunistic species, which can lead to anoxic events and release nuisance or toxic compounds during the degradation of the biomass (Fletcher, 1996;Valiela et al., 1997; Green-Gavrielidis et al., 2018). These blooms alter ecosystem functioning of nearshore environments and limit the services these areas provide (Fletcher, 1996; Gonzales et al., 2013). Macroalgal blooms became more frequent and larger in the 1970s, especially in industrialized countries. Since then, the number of reports from new locations and the magnitude of these blooms have continued to increase (Smetacek and Zingone, 2013). Important research efforts have been developed in order to understand the causes and mechanisms underlying these phenomena, which have demonstrated the key role nutrient over-enrichment and reduced herbivory play in explaining the occurrence of macroalgal blooms (

Biotechnological Potential of Macroalgae during Seasonal Blooms for Sustainable Production of UV-Absorbing Compounds

“…In green algae, 45 species report detectable levels of MAAs, with the highest quantities identified in species from the class Prasiolales, with MAA content of more than 3.5 mg/g DW, such as reported in Prasiola crispa [149], while lower or no detectable MAA quantities are reported in some Ulva species [127]. Many macroalgal blooms are dominated by green macroalgae, with the majority of blooms resulting from Ulva species [150]. In the case of the bloom-forming genus Ulva [151] that leads to overwhelming green tides across the world, mycosporine-glycine and porphyra-334 are confirmed in detectable levels [127].…”

“…Increasing levels of golden algal blooms are reported, especially for Sargassum blooms [150]. Brown algae (the class Phaeophyceae) contain the pigments chlorophyll and carotenoids, including fucoxanthin, which is important for photo and antioxidant protection, as well as polyphenolic compounds phlorotannins and complex carbohydrates laminarin and mannitol [153,154].…”

Shift in algal blooms from micro‐ to macroalgae around China with increasing eutrophication and climate change

“…The recent spread of macroalgal blooms worldwide is causing widespread concern (Bermejo et al., 2023; Lapointe et al., 2021). These extensive seaweed blooms are dominated by the genera Ulva and Sargassum , which cause green tides and golden tides, respectively (Bermejo et al., 2023). The biggest green tide ever recorded occurred in the Yellow Sea of China in 2009, and covered an area of 2100 km 2 (Xiao et al., 2021).…”

“…The reasons that drive the changes have been attributed to water quality and warming (Xiao et al., 2019; Zeng et al., 2019). Previous studies have focused on single types (micro or macro) of algal blooms (Bermejo et al., 2023; Dai et al., 2023; Xiao et al., 2019), ignoring their co‐evolution and interactions. However, we assume that red tides and macroalgal blooms may interact with each other along with the changing environment.…”

“…The recent spread of macroalgal blooms worldwide is causing widespread concern (Bermejo et al, 2023;Lapointe et al, 2021).…”