Glime, J. M. 2017. Nutrient Relations: Requirements and Sources. Chapt. 8-1. In: Glime, J. M. Bryophyte Ecology. Volume 1. 8-1-1 Physiological Ecology. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 17 July 2020 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology/>. CHAPTER 8-1 NUTRIENT RELATIONS: REQUIREMENTS AND SOURCES TABLE OF CONTENTS What Do Bryophytes Require? ........................................................................................................................... 8-1-2 Nutrient Requirements ........................................................................................................................................ 8-1-2 Macronutrients ............................................................................................................................................. 8-1-4 Nitrogen ................................................................................................................................................ 8-1-4 Phosphorus ............................................................................................................................................ 8-1-5 N:P Ratios ............................................................................................................................................. 8-1-6 Calcium and Magnesium ...................................................................................................................... 8-1-6 Iron ........................................................................................................................................................ 8-1-7 Micronutrients .............................................................................................................................................. 8-1-7 Boron .................................................................................................................................................... 8-1-7 Copper ................................................................................................................................................... 8-1-7 Heavy Metals ........................................................................................................................................ 8-1-9 Nutrient Content ................................................................................................................................................ 8-1-10 Habitat Differences .................................................................................................................................... 8-1-10 Streams ............................................................................................................................................... 8-1-10 Bogs and Fens ..................................................................................................................................... 8-1-10 Forests ................................................................................................................................................. 8-1-11 Arctic and Alpine ................................................................................................................................ 8-1-12 Species Differences .................................................................................................................................... 8-1-12 Adaptability and Acclimation .................................................................................................................... 8-1-13 Plant Nutrient Locations.................................................................................................................................... 8-1-14 Cell Wall Sites ........................................................................................................................................... 8-1-15 Intracellular Sites ....................................................................................................................................... 8-1-16 Vertical Distribution .................................................................................................................................. 8-1-16 Nutrient Sources ................................................................................................................................................ 8-1-17 Precipitation ............................................................................................................................................... 8-1-17 Bogs .................................................................................................................................................... 8-1-18 Atmospheric Dust ...................................................................................................................................... 8-1-18 Soil ............................................................................................................................................................. 8-1-19 Micronutrients ............................................................................................................................................ 8-1-19 Litter and the Role of Trees ....................................................................................................................... 8-1-21 Decomposition ........................................................................................................................................... 8-1-22 Snow .......................................................................................................................................................... 8-1-22 The Salmon Story and Other Animals ....................................................................................................... 8-1-23 Fungal Partners .......................................................................................................................................... 8-1-24 pH Relationships ............................................................................................................................................... 8-1-25 Protective Devices ............................................................................................................................................. 8-1-25 Seasonal Nutrient Behavior ............................................................................................................................... 8-1-27 Effects on Species Composition ........................................................................................................................ 8-1-27 Summary ........................................................................................................................................................... 8-1-28 Acknowledgments ............................................................................................................................................. 8-1-28 Literature Cited ................................................................................................................................................. 8-1-28 8-1-2 Chapter 8-1: Nutrient Relations: Requirements CHAPTER 8-1 NUTRIENT RELATIONS: REQUIREMENTS Figure 1. Mosses growing on an old iron stove, demonstrating their rather low nutrient requirements. Photo by Janice Glime. What Do Bryophytes Require? Bowen (1933) claimed that bryophytes are necessarily elements (micronutrients) (Fe, Zn, Mn, Cu, Ni, B, Mo, and limited in nutrient supply by their poikilohydric (state of Cl) are essential (Welch 1995). These seem to be hydration controlled by environment) method of water important for bryophytes as well, but in lower regulation. Their method of receipt of water – concentrations. Nevertheless, the levels of requirements predominantly from rainfall and, for most bryophytes, and tolerance can vary widely not only among species, but almost nothing from ground water – relegates them to also within species (Shaw 1988). receive nutrients that are dissolved in rainwater or that Most knowledge about nutrient requirements of accumulate as dust. After the first few minutes of rainfall, bryophytes comes from culturing them (Voth 1943; Brown those nutrient concentrations are extremely small compared 1982), although more recently we have learned much to soil nutrients and are biased in their relative through the effects of atmospheric pollution. We soon concentrations in very different ways. Therefore, it is not learned that concentrations that favored the growth of surprising that culture conditions designed for tracheophytes in the laboratory were too strong for the tracheophytes are often unsuitable for bryophytes. But is poikilohydric bryophytes, and dilutions of 10:1 seemed this what the bryophytes "prefer"? Or are these conditions more satisfactory. they tolerate and that provide them relatively less Hoffman (1966) performed a complex set of competition from tracheophytes? And do they gain any experiments on the moss Funaria hygrometrica (Figure 2) nutrients from the soil? in which he determined anion (N:P:S) and cation (K:Ca:Mg) combination effects. In his anion experiments, Nutrient Requirements the absence of any of the three nutrients caused poor Even in the slow-growing bryophytes, nutrients can be protonemal growth and no gametophores. On the other a major determinant of both species composition and hand, the protonemata responded quite differently from the diversity (Raabe et al. 2010; Stevens et al. 2010; Schrijver