soil and water

organic (rare) or inorganic complex, heterogenous environment and immense microbial diversity

complex, takes 1000s of years, affected by microbial (metabolic products = organic acids, co2), plant and animal activities, and physical and chemical processes (freeze-thaw, wind/water erosion, dissolution)

microbes (eg phytoplankton)

created by decomposition of organic matter in bogs and marshes, much higher level of organic matter than inorganic matter, fairly rare but v productive

most common

metabolic products, organic acids, CO2

mixing and aerating upper layers

taking up water, releasing organics into soil (as they die)

O: exposed organic matter on surface A: topsoil, lots of minerals, root zone, lots of microbes, active B: subsoil, less available minerals, some microbes (spare populations), somewhat active C: mostly inorganic matter, resembled bedrock (crumbled), sometimes have microbes (spare and metabolically inactive mostly) Bedrock

clay, mineral, organic matter sufaces water, air-filled pores

water –> affects o2 (which will affect aerobes!) nutrient status –> microbial activity limited by C, N, or P availability

introduction of organic matter (eg fungi)

no; the aerobic microbes will quickly use up the O content, and then O-dependent microbes will die, or have to switch to a different form of metabolism

v few microbes are common to all soil samples, immense diversity

soil that surrounds plant roots, significantly different than bulk soil environment –> known as rhizosphere effect large amounts of organic carbon due to plant excretion, therefore a higher number of microbes can grow here

the difference in bulk soil env. vs plant soil env. bc plants greatly influence soil habitat + serve as potential habitat

actual root surface source of root exudates –> sugar, AAs, hormones, vitamins

surface of plant leaf

prokaryotes and microeukaryotes; low metabolic activity (bc low nutrient habitat)

O2 and sunlight

O2 produced near surface, lower O2 at greater depths bc of low solubility and consumption (aka anerobic inhabitants in deeper regions)

areas of aquatic environment that are reached by sunlight; microbes in that environment are able to photozynthesize

at certain times of years, it forms layers and those layers don’t mix - wind and waves would mix it but this doesn’t happen

temperature changing v quickly over a short area (bc of the sunlight not reaching the bottom anymore) anoxygenic photosynthesis by H2S-oxidizing organisms