Effect of nutrient eluted from hedoro brock on growth and survive of Brown algae sprouts

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09660197
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General fisheries
• Research Institution: Tokyo University of Fisheries
• Principal Investigator: MORINAGA Tsutomu Tokyo University of Fisheries, Professor, 水産学部, 教授 (90088196)
• Co-Investigator(Kenkyū-buntansha): ARAKAWA Hisayuki Tokyo University of Fisheries, Assistant Professor, 水産学部, 助手 (40242325)
• Project Period (FY): 1997 – 1998
• Keywords: Survival-type seaweed reef / sea-bottom sediment (hedoro) / nutrient-elution / compression strength of baseplate / Brown algae

Research Abstract

I Results of laboratory experiment (in a year of 1997)
When each sample of blocks submerged in filtrated seawater during the 28 days, hedoro nutrient in the solution increased with time, and in particular, amount of NOィイD23ィエD2ィイD1-ィエD1-N and NOィイD22ィエD2ィイD1-ィエD1-N reached saturation on the 10 th day. Lower the cement ratio is, for instance, fragiler the block makes, the concentrations of NHィイD24ィエD2ィイD1+ィエD1-N and POィイD24ィエD2ィイD1-ィエD1-P eluted inside are higher. The growth ratio of gametophyte as well as sporophyte of brown algae Eisenia bicyclis was the greatest in case of the solution showing the least cement ratio of 30%. On the other hand, the survival ratio of algal sprouts decreased linearly with time, and in case of the solution for hedoro block, the ratio of decrease stood for smaller than that for mortal one.
II Results of outdoor experiment (in a year of 1998)
Diatom inserted in the surface of each specimen block, and Brown algae Eisenia bicyclis did not live there.
In future, such a research would be tried again when we make the hardness of block greater.