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.

Extracellular Enzymatic Activities of Oceanic Pelagic Fungal Strains and the Influence of Temperature

“…Depending on the optimal growth temperature, organisms living there can be psychrophilic or psychrotrophic [ 13 ]. These organisms need to be well adapted to low temperatures, low nutrient availability, and light seasonality [ 14 , 15 ]. Moreover, as low temperatures influence the biochemical reaction rates, organisms must be prepared to overcome those challenges [ 11 ].…”

Cold Adaptation Strategies and the Potential of Psychrophilic Enzymes from the Antarctic Yeast, Glaciozyma antarctica PI12

“…The presence of permeable channels of brine in the semi-solid matrix of frozen seawater allows the growth of sea ice organisms. Ice-associated microorganisms, in particular, play an important role in nutrient (carbon and nitrogen) cycling, recycling and are the beginning of polar food webs, which affects all trophic levels [ 6 ]. Although ice-associated microorganisms are crucial in regulating natural ecosystems and ultimately affect climate change, they are rarely the focus of and are not considered in policy development.…”