The establishment of the non-native seaweed Polysiphonia morrowi in Northern Patagonia: Size of thallus and reproduction

CROCE, M.E.; PARODI, E.R.

AQUATIC BOTANY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 p. 35 - 38

0304-3770

A population of Polysiphonia morrowii,recently introduced in the South West Atlantic Ocean, was studied to determine the degree of its establishment. Monthly variations of: thallus size, proportion of life his-tory phases, and tetrasporangia production, were evaluated from June to October 2010. The erect thalli appeared in autumn, and decayed in spring when they became over grown by epiphytic diatoms. Vegetative thalli were usually smaller than fertile thalli. In spring, the thalli had the maximum mean values of length (199.5mm), thickness(52mm) and driedweight(4g). Although tetrasporophytes represented between 73% and 90% of the thalli collected each month, a few cystocarpict halliwere also found. Variations of thallus size and proportion of life history phases were also studied between 2010 and 2014. The inter annual increase in the proportion of the tetrasporophytic phase and the progressive increase of the size of P. morrowii thalli indicated anongoing establishment of the population in this habitat.