Tank cultivation of Ulva prolifera in deep seawater using a new “germling cluster” method

Abstract

A new "germling cluster" method is proposed for tank cultivation of seaweed in a free-floating form. This method was applied to the tank cultivation of Ulva prolifera using deep seawater (DSW) pumped up from over 300 m depth off the cape of Muroto in southwest Japan. Numerous zoids of U. prolifera were induced by cutting thalli into 1-2 mm long pieces. Three days after fragment production, the zoids were released. The zoid suspension was concentrated to a density of more than 10 4 zoids per mL medium, and placed in a Petri dish for culture. The dense, germinating zoids began to adhere to each other and form aggregations. The germling aggregations were then removed from the bottom of the dish and torn into a large number of small "germling clusters" using an electric mixer. Each cluster contained 10-100 germlings. Once the germling clusters had attained more than 5 mm diameter in culture, they were transplanted as free-floating forms to a 500 L outdoor tank with continuous aeration, to which DSW was supplied at an exchange rate of 3 volumes per day. As a result, the average daily growth rate (DGR) in the tank throughout the year was 37%, though the DGR fluctuated with seasonal temperature changes.

Isolation of seaweed-associated bacteria and their morphogenesis-inducing capability in axenic cultures of the green alga Ulva fasciata

“…Previous research on this alga has dealt with several fundamental aspects of biology, including phenology and ontogeny (Subbaramaiah 1970, Mantri et al in press). Members of the genus Ulva are popular in Japanese and Korean cuisine and are commercially cultivated in these countries (Hiraoka & Oka 2008). But the effects of associated bacteria on this alga's growth, morphology and reproduction have not been examined.…”

Biogas from Marine Macroalgae: a New Environmental Technology — Life Cycle Inventory for a Further LCA

“…Variable with temperature (see figure 5) [19] Increase of the DGR due to nutrient and CO2 [22] *kg VS = kg of volatile solids…”

“…The daily growth rate (DGR) represents the growing rate as a percentage. This can be calculated from the resulting increase in the algal biomass in fresh weight and is expressed as percentage of growth per day, The formula is expressed as follows [19]:…”

“…The algae growing phase is dependent on the temperature of water of the growing medium [18,19,21] and consequently, the seasonal variation of temperature can affect the global biomass production yield.…”

Effects of Environmental Factors on the Zoospore Release and Germling Growth of the Green Macroalga Chaetomorpha linum

“…)와 청각류(Codium spp.) 등 기회종이 대량으로 발생하는 것을 녹조대발생 (green tide)이라고 하며, 이러한 종은 영양염 흡수율이 높 고 빠른 생장을 보이는 특성을 가지며 (Yabe et al 2009;Gao et al 2013;Zhang and Shao 2013;Tsutsui et al 2015), 이러한 녹조대발생은 아시아와 유럽을 포함한 많은 나라에서 보고되고 있다 (Taylor et al 2001;Hiraoka and Oka 2008;Choi et al 2010;Ye et al 2011;Gao et al 2014).…”