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About initiatives before Yamashita Park

Last Updated April 1, 2021

Introduction

This is the steel slag product used
Steel slag products used

In the Yamashita　Koen-mae area, the amount of oxygen (dissolved oxygen) in seawater is low at a depth of -3.0 m in the summer, and it is known that the living environment is harsh. Therefore, through joint research, Yokohama City and JFE Steel Corporation will create a shallow ground with a depth of about 3.0 m, using steel slag recycled materials, etc., and place a living creature attachment base (living place, escape place, etc.) We verified the effect of improving the habitat.

Survey site

The survey was conducted in the waters of Yamashita　Koen-mae.

Results of the survey

Changes in undersea conditions

Water purification by living organisms

Based on the results of a one-year survey in 2016, we estimated the amount of filtered water by filtered-eating organisms such as bivalves and squirrels (organisms that get bait like crunching), about 11,000 kl per day (equivalent to 22 cups of 25m pools) It was estimated that seawater was filtered.

In the sea in the Yamashita　Koen-mae area after the construction of the shallow ground

Changes in living organisms in Test Zone A

There was an increase in living things after installation. In summer, there is a decrease in the number of organisms presumed to be caused by poor oxygen, but the number of confirmed species tends to recover thereafter. In addition, filtration organisms bivalves (mollus gates) and squirts (prototype animal gates) that contribute to water purification have been confirmed.
A survey conducted in August of R1 confirmed a wide area of hydrodynamic transcripts (alphatic animal gates).

This is a graph of the number of confirmed types and coverage of the Yamashita　Koen-mae sea area.
※Both the number of confirmation types and the degree of coverage are the results of counting for the entire test zone A including natural stone.

This is a graph of the number of confirmed types of wards for reference.

Survey reports, etc.

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