Wild fisheries geological record of human activities of the last century. Some specific examples are Eutrophication is an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem. It can result in an increase in the ecosystem's primary productivity (excessive plant growth and decay), and further effects including lack of oxygen and severe reductions in water quality, fish, and other animal populations. The biggest culprit are rivers that empty into the ocean, and with it the many chemicals used as fertilizers in agriculture as well as waste from livestock and humans. An excess of oxygen depleting chemicals in the
Plant to plant communication via mycorrhizal networks help plants in mycorrhizal networks defend themselves against attack by pathogens or herbivores, and transferred nutrients can affect growth and nutrition. Results of studies which demonstrate these modes of communication have led the authors to hypothesize mechanisms by which the transfer of these nutrients can affect the fitness of the connected plants. Plants and fungi form mutualistic symbiotic relationships called mycorrhizae, which take several forms, such as arbuscular mycorrhizae (AM) and ectomycorrhizae (ECM), and are widespread in nature. Host plants provide photosynthetically derived carbohydrates to the mycorrhizal fungi, which use them in metabolism, either for energy or to increase the