Representatives of the Dictyotaceae could be discovered around the globe however are extra various in hotter tropical and subtropical waters. They appear to be notably various within the Australasian area. Dictyotaceae are reasonably sized seaweeds with flattened thalli which will develop as branching ribbons or radiating followers. One fan-shaped species of Dictyotaceae, Padina pavonica, has earned itself the vernacular identify of ‘peacock’s tail'(this species can be notable for being one of many few calcified brown algae). These thalli develop apically from meristematic cells. Dictyotaceae have an isomorphic life cycle with the alternating sexually and asexually reproducing generations being related in general look. Sporangia in asexual people develop as superficial nodules scattered over the floor of the thallus; the ensuing spores often differ from these of different brown algae in missing flagella. The much less considerable sexual people are principally divided between separate women and men (Bittner et al. 2008).
Dictyotaceae are distinct sufficient from different brown algae to have persistently been handled as their very own order (certainly, their sporangia are distinctive sufficient that some very early authors didn’t even regard them as brown algae). Two species discovered round Australasia, Dictyotopsis propagulifera and Scoresbyella profunda, have beforehand been thought-about distinct sufficient to warrant their very own separate households inside this order Dictyotales. Dictyotopsis propagulifera has a monostromatic thallus (that’s, the thallus is just one layer of cells thick). Scoresbyella profunda has an apical rising cell that divides lengthwise to the thallus as a substitute of transversely as in different Dictyotales. Nonetheless, molecular knowledge have indicated that these two genera are nested inside Dictyotaceae and so solely the one household is at the moment recognised. Dictyotaceae has additionally been divided prior to now between tribes Dictyoteae and Zonarieae primarily based on the character of the apical rising cells (Dictyoteae have a single meristematic cell whereas Zonarieae have a cluster or row of cells) and a few authors have even handled them as distinct households. Once more, nevertheless, molecular knowledge haven’t corroborated this division (Bittner et al. 2008).
For many species of Dictyotaceae, their biggest significance to people in all probability comes from the position they play in offering habitats to fish and different marine animals. As with different algae, Dictyotaceae produce a spread of secondary metabolites that serve capabilities reminiscent of defending them from grazers, and a few of these might show to have financial purposes. Some species of Dictyotaceae, however, have grow to be vital invasive species. A dramatic latest instance has been offered by the northern Pacific species Rugulopteryx okamurae which was in all probability first imported to the Mediterranean as a contaminant on farmed oysters (García-Gómez et al. 2020). This species was recorded on the southern coast of France in 2002 and was later recorded on the coast of Ceuta in 2015. Inside a 12 months of the latter document, its presence in Ceuta had reached absolute plague proportions. A lot of the illuminated rocky sea backside was lined by R okamurae, as much as about 90% protection at optimum depths about ten to twenty metres. Over 5000 tons of washed-up seaweed was faraway from the seashores of Ceuta in 2016. Evidently, native seaweeds, and different sessile marine organisms reminiscent of corals, would have been severely impacted by this unfold.
What brought on this dramatic invasion? It could have definitely been an element that defensive metabolites produced by Rugulopteryx okamurae had a destructive influence on opponents. However maybe much more vital an element was local weather change. Rising sea temperatures within the Straits of Gibraltar would have made issues uncomfortable for native marine life used to cooler situations. In the meantime, the subtropical immigrant would have discovered issues more and more to its liking. With its competitors hobbled and nothing to carry it again, R. okamurae was set to take over.
Bittner, L., C. E. Payri, A. Couloux, C. Cruaud, B. de Reviers & F. Rousseau. 2008. Molecular phylogeny of the Dictyotales and their place throughout the Phaeophyceae, primarily based on nuclear, plastid and mitochondrial DNA sequence knowledge. Molecular Phylogenetics and Evolution 49: 211–226.
García-Gómez, J. C., J. Sempere-Valverde, A. R. González, M. Martínez-Chacón, L. Olaya-Ponzone, E. Sánchez-Moyano, E. Ostalé-Valriberas & C. Megina. 2020. From unique to invasive in document time: the intense influence of Rugulopteryx okamurae (Dictyotales, Ochrophyta) within the strait of Gibraltar. Science of the Whole Surroundings 704: 135408.