10.2 ecosystems, energy and nutrient cycling cont. Flashcards
what is climate change?
-mean global temperature has increased by 0.62 plus minus 0.07 degrees Celsius above the 20th century average
-the yar 2022 was the sixth warmest year since global records began in 1880 at 0.86degrees above the 20th century average of 13.9 degrees
-2023 was the warmest year in the 174-year observational record, surpassing the previous joint warmest years, 2016 at 1.29(+-0.12) above the 1850-1900 average and 2020 at 1.27 (+-0.13).
what are GCMs?
general circulation models (GCMs) have been developed to help scientists determine how increasing concentrations of greenhouse gases may influence large-scale patterns of global climate
where do CO2 emissions come from?
currently, 70% of the total CO2 emissions from the burning of fossil fuels comes from developed countries
what is nitrogen cycling?
human activity has significantly influenced the global nitrogen cycle
-conversion of native forests and grasslands to agricultural fields
-application of chemical fertilizers to agricultural fields
-automobile exhaust and combustion add N2O, NO, and NO2 to the atmosphere
what is the phosphorus cycle?
-phosphorus (P) can only be cycled from land to sea and is not returned via biogeochemical cycle
-the main reservoirs of P are rock and natural phosphate deposits
-phosphorus is released by weathering, leaching, erosion, and mining
-in most soils, only a small fraction of total phosphorus is available to plants
what is the sulfur cycle?
the sulfur has both sedimentary and gaseous phases
-in the long-term sedimentary phase, sulfur is tied up in organic and inorganic deposits and is released by weathering and decomposition
-the gaseous phase permits sulfur to circulate on a global scale
what are atmospheric sulfur sources (as H2S)?
-combustion of fossil fuels
-volcanic eruptions
-ocean surface exchange
-decomposition
-atmospheric sulfur dioxide (SO2) is carried back to the surface in rainwater as weak sulfuric acid (H2SO4)
what do the graphs look like of primary succession after acid rain?
what is an example of a heavy metal?
-mercury (Hg) contamination in aquatic ecosystems is of great concern
methylated Hg is highly toxic and is a bioaccumulant
-produced from industrial sources
-can form after the release of Hg from the burning of fossil fuels (in anaerobic aquatic habitats, bacteria can convert Hg to its methylated form)
what is heavy metal concentrations and biomagnification?
-organic pollutants and radionuclides accumulate at higher trophic levels
-amounts in soil and water are negligible
-once in the food chain these substances increase in concentration via biomagnification
-biomagnification can increase concentration of a toxin with every trophic level to orders of magnitude higher than background
