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Most scyphomedusae jellyfishes recorded in Korean waters are temperate and subtropical species. In the present study, two cold-water jellyfishes from Korean waters are first described. Scyphomedusae were collected from the coasts of Gangneung and Ulsan of the East Sea, and Boryeong, and the eastern area of the Yellow Sea from June 2006 to May 2015. Scyphomedusae collected in Ulsan and Gangneung were identified morphologically as Aurelia limbata Brandt, 1835. Their umbrella was 250-500 mm in width and 30-50 mm in height; the exumbrella was white and the subumbrella was dark brown in color. The vascular system was complex with anastomosed branches. Individuals of this species lived at about 6.6-9.9°C and 30-50 m depth in Korean waters. Scyphomedusae collected from the center of the Yellow Sea and from Boryeong were identified as Parumbrosa polylobata Kishinouye, 1910. Their umbrella was discshaped, 80-200 mm in width and 20-40 mm in height. Its milky white gonads could be seen through the transparent exumbrella. The stomach cavity was round and flat with four interradial cavities connected by subgenital cavities, and the four oral arms were bifurcated and spearhead shaped. Individuals were found at about 6.4-10.0°C and 40-90 m depth in Korean waters. The identities of both species were confirmed by molecular analysis using nuclear ribosomal DNA sequences.

A filamentous green alga Cladophora vadorum (Areschoug) Kützing, bloomed at Shangrok Beach, Buan, Republic of Korea, in September 2015. This alga is currently distributed worldwide. Concentrations of total nitrogen (TN), total phosphorus (TP), dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) were analyzed in the bloom area and compared to those of other areas in the vicinity. DIN and DIP concentrations were similar to those of other areas. However, TN and TP were as much as six and ten times higher than in other areas, respectively. As in other Cladophora species, the bloom of C. vadorum at Shangrok Beach in 2015 appears to have depended on the TP concentration in the seawater. This suggests that blooms in the area can be controlled by reducing TP.Key words: Bloom, Cladophora vadorum, Total Phosphorus, Total Nitrogen This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licens (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The actiniarian sea anemone, Entacmaea quadricolor, and the scleractinian coral, Alveopora japonica, host symbiotic dinoflagellates belonging to the genus Symbiodinium (Freudenthal). We studied the hostÁsymbiont specificity of these two anthozoan hosts in the northwestern Pacific Ocean. Symbionts within the two hosts were identified using partial large subunit (LSU) ribosomal DNA (rDNA) and complete internal transcribed spacers (ITS) 1 rDNA regions. The host, E. quadricolor, was identified using the partial LSU rDNA molecular marker. Genetic analysis showed that E. quadricolor only harbors dinoflagellates belonging to subclade C1/3 of the genus Symbiodinium. Moreover, no genetic variation was detected among the symbionts of E. quadricolor within the study region (Korea and Japan), even though the two distant sites were separated by more than 1000 km, at collection depths of 1 m in shallow and 13Á16 m in deep water. Whilst scleractinian corals host multiple Symbiodinium clades in tropical waters, A. japonica, sampled over a wide geographical range (800 km) within the study region, only hosts Symbiodinium sp. clade F3. The high specificity of endosymbionts in E. quadricolor and A. japonica within the northwestern Pacific Ocean could be accounted for because symbiotic dinoflagellates within the host anemones appear to be acquired maternally, and the Kuroshio Current might affect the marine biota of the northwestern Pacific. However, the consistency of the symbiotic relationships between these two anthozoan hosts and their endosymbionts could change after climate change, so this symbiotic specificity should be monitored.