Algicidal Marine Bacteria Isolated from Northern Hiroshima Bay, Japan

Abstract

Marine bacteria that kill the noxious red tide flagellate Chattonella antiqua (Raphidophyceae) were screened and isolated from northern Hiroshima Bay, the Seto Inland Sea, Japan in 1991. Four strains (S, K, D, R) of Alteromonas spp. were selected and examined on characteristics of algicidal activities. Strains S and R showed wide algicidal range killing all cells of the 3 raphidophycean flagellates, 2 dia toms, and one dinoflagellate examined, in co-culture. Algicidal activities of the strains K and D depend on prey phytoplahkton species. Bacterial culture filtrate experiment shows that the bacterial strains K and D give lethal effects on C. antiqua by means of extracellular products, and the strains S and R not by such substances but by predation. If one or two bacterial cells were inoculated into C. antiqua cul ture, all of the host cells were killed by the 4 strains of algicidal bacteria within 7 days. All of the 4 bac terial strains could proliferate in filter-sterilized seawater, indicating their ubiquitous existence in the coastal sea. We suggest that the algicidal activity by bacteria may be a significant factor influencing the population dynamics of phytoplankton, and potentially might account for rapid termination of red tides in the coastal sea.

Allelopathic interactions between the bacillariophyte Skeletonema costatum and the raphidophyte Heterosigma akashiwo

“…For example, Imai et al (1995), Nagasaki et al (1994a,b) and Tarutani et al (2000) reported that bacterial attack and viral infection induce bloom termination. To reveal the allelopathic interactions between phytoplankton species, we conducted bi-algal culture experiments using axenic cultures of S. costatum and H. akashiwo.…”

Bridging the Gap between Knowing and Modeling Viruses in Marine Systems—An Upcoming Frontier

“…In the ERSEM model, for instance, it was formulated that lysis products from phytoplankton groups were partly particulate and partly dissolved, with the particulate fraction dependent on the actual nutrient cell quota (Baretta-Bekker et al, 1995, 1997. For primary producers, lysis was defined to included factors such as mechanical damage (e.g., sloppy feeding Imai et al, 1993;Strom et al, 1997), nutrient shortage (Berges and Falkowski, 1998), virus and bacteria activity (Imai et al, 1993(Imai et al, , 1995. A way to achieve this consisted in defining a background lysis rate, an increased lysis rate proportional to nutrient stress and a phytoplankton density dependent term.…”

Algicidal activity of polyunsaturated fatty acids derived from Ulva fasciata and U. pertusa (Ulvaceae, Chlorophyta) on phytoplankton

“…Chemical agents such as copper sulfate (Steidinger, 1983) and hydrogen peroxide (Ryu et al, 1998) have been performed as algicidal substances but are known to have a wide-spectrum in sterilizing effects. Viruses (Garry et al, 1998), bacteria (Imai et al, 1995), planktonic ciliates (Kamiyama, 2002) and heterotrophic dinoflagellates (Nakamura, 2002) as biological control also have been proposed. However, these methods also have the potential of disastrous environmental consequences (Jeong et al, 2000).…”