Advances in cultivation of Gelidiales Michael Friedlander Originally published in the Journal of Applied Phycology, Vol 20, No 5, 1–6. DOI: 10.1007/s10811-007-9285-1 # Springer Science + Business Media B.V. 2007 Abstract Currently, Gelidium and Pterocladia (Gelidiales) Introduction are collected or harvested only from the sea. Despite several attempts to develop a cultivation technology for Gelidium, As far as I know there is no current commercial cultivation no successful methodology has yet been developed. Initial of Gelidiales. Despite several attempts to develop a steps towards developmental efforts in Portugal, Spain, cultivation technology for Gelidium and Pterocladia, so far South Africa and Israel have been published. More no successful methodology has been developed. Because of developments have probably been performed but have not the proprietary nature of commercial cultivation, a success- been published. Two different technological concepts have ful technology may have been developed but has remained been tested for Gelidium cultivation: (1) the attachment of unpublished. Gelidium and Pterocladia (or Pterocladiella) Gelidium fragments to concrete cylinders floating in the are currently only collected or harvested, as opposed to sea, and (2) free-floating pond cultivation technology. other useful seaweeds for which cultivation technology has These vegetative cultivation technologies might be partially been developed. The reasons for this situation are discussed optimized by controlling physical, chemical and biological in this review, including all important variables affecting growth factors. The pond cultivation technology is the Gelidium and Pterocladia growth. This review will rely much more controllable option. The effects of all factors are mostly on Gelidium studies since most of the relevant discussed in detail in this review. It seems that the main information in the literature deals with Gelidium. difficulty with cultivation of Gelidium is its low growth rate. The claimed yields of the two technologies are far from being economically attractive at this stage of their Initial steps development. It seems that in order to introduce Gelidium into commercial cultivation, major efforts in genetic Gelidium has been cultured in Korea since 1989 (Melo improvement through selection or genetic engineering will 1998) and in China (Fei and Huang 1991). Early cultivation be required. Only high yield strains will have the potential systems for Gelidium species have also been described in to compete economically with the present harvesting Spain and Portugal (Salinas 1991; Seoane-Camba 1997; tradition. However, accumulated experience with genetic Melo 1998). Cultivation of intertidal G. pristoides (Turner) improvement of other useful seaweed species suggests that Kützing in the sea was reported from South Africa (Aken et this is possible. al. 1993), and growth experiments were performed in tanks with G. crinale (Turner) Gaillon and Pterocladiella Keywords Gelidium . Pterocladia . Gelidiales . Cultivation capillacea (Gmel.) Santelices and Hommersand in Israel (Gal-Or and Israel 2004;Boulusetal.2007). The ecological studies carried out with Gelidium and Pterocla- dia can be reviewed by following the major factors * M. Friedlander ( ) controlling the growth of these seaweeds. Evaluation of Israel Oceanographic and Limnological Research, P.O.B. 8030, Haifa 31080, Israel these studies may answer the major question of "why is e-mail: [email protected] there no mass cultivation of Gelidium and Pterocladia"? Borowitzka et al. (eds.), Nineteenth International Seaweed Symposium. DOI: 10.1007/978-1-4020-9619-8_1 1 2 Borowitzka et al. (eds.) Technological factors Irradiance Two major technologies have been suggested for Gelidium G. pulchellum (Turner) Kurtz was cultured under controlled cultivation: sea farming and tank culture. Both use laboratory conditions. Maximum growth rate (10.0% day -1) Gelidium fragments for initiation of the cultures. was obtained at 130–240 μmol photons m -2 s -1 under continuous light and aeration (Sousa-Pinto et al. 1999). The Sea culture photosynthetic capacity of G. sesquipedale decreased with depth, revealing a 'sun' and 'shade' acclimation pattern (Silva In one culture experiment in Galicia (Spain), fragments et al. 1998). Photosynthesis is probably limited in G. of G. sesquipedale (Clemente) Born. et Thur. were canariensis (Grunow) Seoane-Camba,G.arbusculaBory attached to limestone cylinders placed in the sea (Seoane- ex Boergesen and Pterocladiella capillacea by incident light Camba 1997). This technology has technical, biological in their natural habitats (Mercado et al. 2001). Gelidium and ecological advantages. However, it became clear that sesquipedale in chemostats showed higher growth rates non-contaminated seawater and a high level of hydrody- under blue and red light than under white light of the same namics are major prerequisites for a Gelidium farm because photon-fluence rate (40 μmol m -2 s -1; Carmona et al. 1996). of epiphytes and competitors (Seoane-Camba 1997). Reattachment of apical portions of G. sesquipedale increased Cultivation of intertidal G. pristoides in the sea in South under longer days compared to under shorter days (Juanes Africa was attempted by suspending plants in net bags, or and Puente 1993). All these studies indicated that irradiance growing on limpet shells on ropes at different depths. is a significant growth factor, and indicated a positive However, after significant growth for 2 weeks, the thalli response to irradiance range. However, summer and winter degenerated for unknown reasons (Aken et al. 1993). outdoor experiments conducted in small aerated seawater Systems with G. rex Santelices et Abbott hanging in open tanks with G. crinale in Israel, showed that light intensity sea were developed in Chile after reattachment to shells changes were less or non effective, with ambient conditions (Rojas et al. 1996). being almost optimal (Boulus et al. 2007). Tank culture Temperature In Israel, Gelidium and Pterocladia were grown in Temperature was defined as the major seasonal limiting outdoor tank culture systems adopted from other seaweed factor for G. crinale, and positively affected weekly cultivation methods, included the use of 40 L tanks with growth rate. The average daily growth rate was about continuous water flow and aeration (Gal-Or and Israel 6.5% day-1 for the months of active growth (Boulus et al. 2004;Boulusetal.2007). The advantages are that tank 2007). The relative abundance of G. robustum (Gardn.) culture allows control of most variables, and is relatively Hollenberg et Abbott in Mexico under normal conditions protected from grazers and epiphytes. The disadvantage is and during La Niña showed a positive correlation with sea its high cost. Other experiments with Gelidium free- surface temperature (Hernandez-Guerrero et al. 2000). floating tank cultures in Spain claimed to generate healthy Reattachment of apical portions of G. sesquipedale in the plants in 2–3 months, with a nice deep-red color, but very laboratory increased under a limited range of 16–18°C as low growth rates (Salinas 1991a, b;Sosaetal.2006). compared to 20–22°C (Juanes and Puente 1993). These Looking at the effects of the major growth factors and at studies support a strong effect of temperature change on the maximal reported growth rates might improve our Gelidium cultures. understanding of the obstacles to developing mass cultivation. Water movement A lag period of 3 months showed a positive correlation in Physical factors situ between relative abundance of G. robustum and upwelling index / wind speed (Hernandez-Guerrero et al. The major physical factors involved in culture of 2000). Zones with greater water movement in situ (1.4 m s -1) Gelidium and Pterocladia are temperature, irradiance and stimulated the growth of G. robustum (1.0% day-1). relative seaweed velocity. The optimal combination of Growth was directly proportional to water movement these factors might lead to maximal yields. It is possible to under semi-controlled cultivation conditions in Mexico, study the requirements for these factors from limited and treatment with the greatest dynamics demonstrated experiments conducted in the sea, in tanks or in the growth of 3.6% day-1 (Pacheco-Ruiz and Zertuche- laboratory. Gonzalez 1995). Nineteenth International Seaweed Symposium 3 — À Thus, all three physical factors irradiance, temperature capacity for using the external pool of HCO3 ; therefore and water movement—seem to be major effective growth photosynthetic rates in a controlled environment room were factors both in the sea and under controlled conditions. dependent on CO2 availability (Mercado et al. 2001). On the other hand, the weekly outdoor growth rate of G. crinale was not significantly affected by addition of a Chemical factors carbon source (CO2 or NaHCO3) or by the controlled maintenance of pH 8. This suggests that a daily pH increase The major chemical factors are the concentration of up to pH 9 does not decrease the growth rate under these inorganic nitrogen and phosphate in seawater, and also the conditions as this species consumes bicarbonate, which is concentration of dissolved inorganic carbon (DIC) in the more abundant at high pH (Boulus et al. 2007). À form of CO2 or HCO3 . Several laboratory and outdoor The positive growth effect of nitrogen and phosphate experiments can supply a basic understanding of these additions to Gelidium and Pterocladia culture is fully factors. supported; however,