INTRODUCTION

A fungal component of the marine biota was only recognized as recently as 1944 (Barghoorn & Linder, 1944), and it was not until the 1960s that studies commenced to assess the extent and diversity of fungi in marine systems. Since this time, considerable effort has been exerted to uncover marine fungal diversity, with high decadal discovery indices in the 1970s and 80s (Hawksworth, 1991), resulting in around 1000 fungal species known today from marine environments. Nevertheless, it is hardly surprising that, with the extent of marine environments globally, we probably have a very incomplete view of fungal diversity, together with their frequency and function in these ecosystems. The objective of this review is to assess the extent of our present knowledge and to highlight future directions to further elucidate their biology and ecology.

THE NATURE OF MARINE ENVIRONMENTS

Marine ecosystems are globally extensive, and account for around 70 % of global surface area. They can be defined generally as aquatic systems influenced by substantial concentrations of salts, particularly sodium chloride, from existing oceanic systems. Seas and oceans divide between regions bordering and influenced by terrestrial regions and the open ocean, which is strongly zoned through the water column. These broad boundaries are illustrated in Fig. 1, which also details linkages between marine compartments.