Report | September 9, 2025
First record of Caulerpa prolifera (Bryopsidales, Chlorophyta) beyond 60mdepth in the SW Tenerife Island, Spain
Abstract
The genus Caulerpa J. V. Lamouroux, 1809 (Bryopsidales, Chlorophyta) includes more than 100 species worldwide and, due to its morphological variation and dispersal mechanism, can colonize different substrates. As part of scientific surveys, a Remotely Operated Vehicle (ROV) recorded video transects along the southwest side of Tenerife Island (30000 m,2 depth range 6.7–156 m). Out of 55 videos recorded, 24 over sandy bottom were found with patches of C. prolifera. This represents a first record of C. prolifera in a depth range of 25–83 m in the Canary Islands, Spain.
The genus Caulerpa J. V. Lamouroux, 1809 (Bryopsidales, Chlor[1]ophyta) has more than 100 species in shallow waters globally distrib[1]uted, from circum-tropical to warm temperate geographic area (Zubia et al., 2020). The highest Caulerpa diversity has been registered in the Caribbean, Indo-Malay rand in the South of Australia (Zubia et al., 2020), but species-level identification is still under debate due to mul[1]tiple challenges in the identification (Jacobs, 1994; Cacabelos et al., 2019). This seaweed indeed is characterized by high phenotypic plas[1]ticity that leads to the overlap of morphological traits among different species; these morphological traits, such as thallus appearance or branch shape, can be strongly influenced by environmental factors, increasing the blur among species boundaries. In addition, the use of historical names based on the morphology creates confusion when integrated with molecular data as in some case the old nomenclature may not corre[1]spond to genetically distinct/same species (Belton et al., 2014; de Sen[1]erpont Domis et al., 2003; Fern´ andez-García et al., 2015; Verbruggen et al., 2013; Zubia et al., 2020). This genus exhibits remarkable adapt[1]ability, occupying diverse environmental niches, that sometimes can overlap with seagrasses like Cymodocea nodosa (Oliv´e et al., 2021; Zubia et al., 2020). These niches vary significantly with temperature, light availability, season, depth, and water movement. The composition and texture of the benthic substrate also play a crucial role in their establishment (Crockett and Keough, 2014; Fernandez-García ´ et al., 2015; Ohba et al., 1992; Zubia et al., 2020).
These factors can affect growth and nutrient uptake causing different responses even at the species and population levels, showcasing their ecological versatility in various marine environments. Caulerpa can spread and colonize various habitats rapidly, thanks to its dispersal mechanisms, which include fragmentation expansion and stolon elongation (Parreira et al., 2021), creating patches or meadows over mud or sandy bottoms but also rocky or mixed substrata (Cunha et al., 2013). Caulerpa prolifera as other Bryopsidales is a siphonous green alga (SGA). These algae depend on a non-cellular cylindrical structure (siphonous), which consists of one large tubular cell containing a central vacuole, filled with water and ions that exert pressure against the walls, resulting in a characteristic plump appearance, with the other cellular components (e.g. multiple nuclei or a macronucleus, chloroplasts, etc.) arranged around it (Del Cortona et al., 2020; Vroom and Smith, 2003). Moreover, the distinctive biology and structural arrangement of Caulerpa species play a significant role in the proliferation of these macroalgae, complicating their detection through conventional environmental DNA methods, which have recently been employed to swiftly identify the presence of invasive species, thereby exacerbating the challenge in the eradication (Waters et al., 2023).
