Effect of the commercial extract of the brown alga Ascophyllum nodosum Mont. on Kappaphycus alvarezii (Doty) Doty ex P.C. Silva in situ submitted to lethal temperatures Rafael Rodrigues Loureiro & Renata Perpetuo Reis & Rafael Guedes Marroig Received: 7 May 2013 / Revised: 7 July 2013 / Accepted: 8 July 2013 # Springer Science+Business Media Dordrecht 2013 Abstract Kappaphycus alvarezii is being introduced in sev- eral countries and in some of them there is a need to adapt this cultivation to periods with lethal temperatures, such as the 16–18 °C that occurs in the winter in southern Brazil. Moreover, there is the need to maintain the seedlings during this lethal temperature period. Considering the promising results obtained with the commercial powder extract of Ascophyllum nodosum (Acadian marine plant extract powder—AMPEP) treatment in the cultivation of K. alvarezii in vitro and in the sea allowing more resistance to epiphytes and increasing the growth rate and carrageenan yield, it was hypothesized that seedlings previously subjected to an AMPEP treatment could be more resilient to lethal temperatures. The daily growth rate and carrageenan yield and gel quality (gel strength and gel viscosity) of K. alvarezii in vitro previously treated with AMPEP were analyzed under temperature stress. The daily growth rates and the gel strengths of the AMPEP-treated sam- ples were increased. In spite of the lower carrageenan yield and lower gel viscosity, the values were within the ones accepted by the carrageenan industry. Thus, the treatment of the seedlings of the K. alvarezii with AMPEP solution can be used as an alter- native to lower temperature effects on crops as a preventive action for the cultivation of the seedlings in tanks and in the sea in periods of low temperatures at sea. Keywords Aquaculture . Biotechnology . Improvement . Lethal temperatures . Resilience Introduction Kappaphycus alvarezii Doty (Doty) ex P.C. Silva is the main source of raw material for the carrageenan industry (Bindu and Levine 2011; Bixler and Porse 2011). To meet the Brazilian demand for carrageenan, this species was initially introduced in Brazil in the late 1990s for experimental pur- poses, followed by the introduction of commercial farms. However, there was a need to adapt K. alvarezii cultivation techniques to some different environmental factors not suited to the culture of this species in this new environment. A solution for Brazilian cultivation of K. alvarezii was apply- ing a floating rafts system made with PVC and the use of a tubular net technique in places with muddy bottoms and greater water movement. This cultivation system has spread all along the area allowed for commercial cultivation of K. alvarezii by the Brazilian Government in the southeastern coast (Góes and Reis 2011). Hayashi et al. (2011) had success with experimental cul- tivation of K. alvarezii in the southern Brazil, Florianópolis, Santa Catarina state, using the same technique. However, during winter, the water temperatures (16–18 °C) in their sampling area were lethal to the cultivated samples. For the feasibility of the cultivation of K. alvarezii in this area, there is the need to allow the growth of this species in low tem- peratures. Hayashi (personal communication) commented that the better way to do this is to cultivate this alga in tanks during the months with low temperatures. Another option that could be established in sites with low temperatures consists of getting healthy seedlings to be cultivated once the cold season ends. Moreover, assuming that the loss of seedlings will make future cultivation attempts futile, there will be a need to translocate seedlings from other crops, increasing costs. To prevent the introduction of organisms R. R. Loureiro : R. P. Reis (*) : R. G. Marroig Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, CEP 22460-030 Rio de Janeiro, RJ, Brazil e-mail: rreis@jbrj.gov.br J Appl Phycol DOI 10.1007/s10811-013-0085-5