Epiphytic diatoms upon sea-weeds (Zostera marina Linnaeus) from Japan (II)

Abstract

We classify epiphytic diatoms on samples of the seaweed Zostera marina Linnaeus collected on Sakushima Island in Mikawa Bay, Japan. The island is the largest one in the Mikawa Bay and has long been inhabited but nonetheless remains a rich natural habitat. This report covers 17 genera and 39 species discovered in a survey conducted in 2009. It includes SEM photographs of Licmophora californica, the diatom mainly appearing, and a description of its morphological characteristics. The seaweed Zostera marina Linnaeus provides an important egg-laying and growth environment for fish and shellfish. Its presence, however, has been depleted since the 1970s because of water pollution, oligotrophication, and land reclamations associated with coastal developments such as factories and an airport. With very few exceptions, there has been little recovery from these losses up to the present. The seaweed is not only an important resource in itself, but the epiphytic diatoms living upon it also have a primary producer significance as a feed-source for fishes and shellfish in these coastal waters. Our investigation of the epiphytic diatoms on Zostera marina is also part of a broader study of the flora of diatoms in both marine and brackish waters.