Bringing Light Back to the Reef Sea REAL Block Story circa 2000

Bringing Light Back to the Reef Sea REAL Block Story circa 2000

From the late 1980's to the 1990's, rocky reef landscapes where seaweed used to stand in colonies were rapidly disappearing due to the quiet progress of rocky shore scorching along the coast of Japan. The meandering of the Kuroshio Current, rising seawater temperatures, decreasing nutrients, abnormal proliferation of sea urchins, and topographical changes due to coastal development have all intertwined in complex ways to destroy the environment that supports seaweed colonization. The scorching of the rocky shore not only resulted in the loss of seaweed, but also deprived young fish of a place to hide and grow, leading to a decline in fish catches and the weakening of coastal ecosystems.

In the 2000s, the Fisheries Agency and the Ministry of the Environment promoted the restoration of seaweed beds and tidal flats as a priority policy of the Japanese government, and demonstration projects were carried out in various regions. One of the technologies that attracted attention was the REAL block, which artificially reproduces a reef environment. REAL stands for "Reef Enhancement for Algal Life," and is based on the concept of using artificial structures to create microtopography for the natural attachment and growth of seaweed. The REAL block was designed to reproduce these features by adjusting the surface roughness and shape so that the light exposure and the speed of the currents would be moderate.

The recesses and shadows of only a few millimeters are important for the initial success of seaweed. The design also protects young algae from feeding damage by creating gaps that are difficult for sea urchins to penetrate. The combination of multiple blocks creates changes in the water flow, encouraging the establishment of small crustaceans and shellfish, resulting in the formation of a small but multilayered ecosystem. In this way, the REAL blocks were not only a technology for seaweed, but also an ecological engineering experiment aimed at restoring the base structure of the sea.

The Web-based public information also records that seaweed beds including REAL blocks have been widely created in Sutsu Bay in Hokkaido and along the Sanriku coastline on the Sea of Japan side of Hokuriku and San'in regions. The Ministry of the Environment's seaweed bed tidal flat restoration project report from around 2005 confirmed the effectiveness of the project in restoring Hondawara and increasing the number of juvenile fish in several areas. In recent years, seaweed beds have been attracting attention as a source of blue carbon that absorbs CO2, and seaweed bed creation technology is being treated as part of climate change countermeasures.

The REAL block is a technology that gently provides a starting point for nature to regain its own strength, rather than imposing man-made objects as a substitute for nature. The recovery of the ocean does not happen overnight; it requires an environment where the tides and seasonal light continue to work slowly, and the REAL Block continues to play a role in setting the stage for the quiet regeneration of seaweed forests while accompanying the flow of time.