Progress in Microbial Ecology in Ice-Covered Seas

Abstract

Sea ice seasonally covers 10% of the earth's oceans and shapes global ocean chemistry. The unique physical processes associated with sea ice growth and development shape the associated biological diversity and ecosystem function. Microbes make up the base of all marine food webs and the overwhelming majority of biomass in the sea ice ecosystem. Despite their biomass, microbial processes are not fully integrated into marine ecosystem models. Recent applications of novel molecular biology technologies to studies of marine ecology have elucidated numerous microbial-mediated processes interfaced by previously unknown organisms and processes. These discoveries are yielding more in-depth studies on the relevance of mixotrophy, the ecology of fungi, and the interplay between major microbial clades. In ecosystem studies, the basis of the food web is frequently neglected even though the accessibility of energy, recycling of nutrients , and parasitism are crucial factors shaping the environment for grazers and higher trophic levels. In this review, we focus on the species composition, abundance, and functions of microalgae, bacteria, archaea, fungi, and viruses in the sea ice-covered seas throughout the year. A strong emphasis will be put on advances in molecular methods that empower scientists to further investigate microorganisms in more detail. Since microbes make up the majority of all oceanic biomass, we believe that it is impossible to accurately forecast the biological fate of polar marine ecosystems without placing a proportional emphasis on microbes relative to their biomass.