The Japanese alga Polysiphonia morrowii (Rhodomelaceae, Rhodophyta) on the South Atlantic Ocean: first report of an invasive macroalga inhabiting oyster reefs

Abstract

Conspicuous tufts of the filamentous algae Polysiphonia Greville inhabit the reefs of Crassostrea gigas on the Atlantic Patagonian coast. The population was recorded for the first time in 1994 and identified as P. argentinica. This study exhaustively investigated the morphology and reproduction of specimens and the seasonality of the population. The results revealed the identity of the specimens as the invasive Japanese macroalga Polysiphonia morrowii Harvey, on the basis of several striking features: the setaceous and tufted thalli, the corymbose growing apices, the endogenous axillary branches, the urceolate cystocarps and the sharply pointed branches. Sexual reproduction was evidenced; however, fertile male gametophytes were absent in the samples. The population was found almost all year round, but its abundance became higher in autumn and winter. The present study constitutes the first record of this invasive macroalga on the South Atlantic Ocean; the fourth record of an exotic macroalgal species on the Atlantic Patagonian coast; and the first record of an invasive species related to the establishment of C. gigas in Atlantic Patagonia.

First catalogue of benthic marine macroalgae from glacier-influenced environments of the Beagle Channel, deposited in the new Sub-Antarctic Cryptogamic Herbarium (SCH) of the University of Magallanes

“…En la base, se adhiere al sustrato a través de rizoides unicelulares adventicios. Hábitat: Intermareal y submareal somero, asociadas a pozas de marea, rocas, terrazas, conchas y epifita a macroalgas (Boraso de Zaixso, 2013;Croce & Parodi, 2014;Mendoza & Nizovoy, 2000;Kim et al 2004;). Código HCS: LMS00001126.…”

Bioenergetic Model of the Highly Exploited Shark Mustelus schmitti under a Global Warming Context

“…Although these estimates can be improved by incorporating populationspecific information, these preliminary assessments provide a quantitative framework for understanding how this population interacts with the environment [23,81]. The area used in the practical example has an important ecological value as it holds greatly biodiverse communities, owing to a high environmental complexity, composed of diverse aquatic environments such as wide muddy intertidal zones, sandy bottom beds, sand and gravel beaches, islands [26,82], and more recently, Magallana gigas reefs [83]. The refuge offered within the waters of this bay makes it an ideal nursery area [84] for many fish species, most of which are important, highly exploited, fisheries resources, among which M. schmitti stands out [30][31][32]50,85].…”

Studying mesoalgal structures: a non-destructive approach based on confocal laser scanning microscopy

“…Providing the base of the benthic food web, algal communities can rapidly respond to alterations in environmental factors (Campana et al 2009, Fricke et al 2014) and are commonly used as indicators for water quality (Ballesteros et al 2007, Neto et al 2010. Driven by human activities, benthic algal communities worldwide have shown strong alterations (Campana et al 2009), reaching dramatic proportions in the formation of intense blooms (Valiela et al 1997, Teichberg et al 2010 and expansion of different algal species (Fricke et al 2013, Croce andParodi 2014). Consequently a good knowledge of the composition and ecology of benthic algal communities is needed to understand and predict environmental changes.…”