抄録
Marine debris issues have gained a significant concern recently due to their impacts to coastal and marine environments. Knowledge on their abundance, distribution and seasonal variation are still limited in many aquatic environments including Kagoshima bay. This study was conducted in three phases from the year 2010 to 2014. Field study in Oosumi peninsula and along Kotsuki river was conducted on November, 2010 to investigate the abundance and distribution of micro size debris. Then, in Kagoshima bay three field studies were carried out to investigate spatial distribution and seasonal changes of marine debris along its coastline and on sea surface from the year 2011 to 2014. Kagoshima bay opens to the south of Kyushu island and is affected by Kuroshio current which probably carries marine debris into the bay. In addition there are several major rivers which carry debris into the bay. The size of the bay is similar to Tokyo bay, therefore field studies in and along its coastline can be representative study to reveal qualitative and quantitative characteristics of marine debris inside a bay in Japan. As a result, EPS fragments dominated the distribution in almost all surveyed beaches (over 90%). Rainfall and natural disasters (i.e. typhoon) contributed significantly to higher deposition levels of micro debris on beaches.
