Freshwater ecosystems are dynamic hubs of biogeochemical activity. Nutrient cycling , driven by carbon, nitrogen, and phosphorus, forms the backbone of these systems. These processes fuel primary production and decomposition , shaping the intricate food webs that thrive in lakes and rivers.
Physical factors like water residence time and stratification play crucial roles in nutrient distribution. Meanwhile, human activities such as eutrophication and acid rain are altering these delicate balances. Understanding these processes is key to preserving the health of our vital freshwater resources.
Biogeochemical Processes in Freshwater Ecosystems
Biogeochemical processes in freshwater
Top images from around the web for Biogeochemical processes in freshwater Biogeochemical Cycles | Microbiology View original
Is this image relevant?
Biogeochemical Cycles and the Flow of Energy in the Earth System | Sustainability: A ... View original
Is this image relevant?
3.2 Biogeochemical Cycles | Environmental Biology View original
Is this image relevant?
Biogeochemical Cycles | Microbiology View original
Is this image relevant?
Biogeochemical Cycles and the Flow of Energy in the Earth System | Sustainability: A ... View original
Is this image relevant?
1 of 3
Top images from around the web for Biogeochemical processes in freshwater Biogeochemical Cycles | Microbiology View original
Is this image relevant?
Biogeochemical Cycles and the Flow of Energy in the Earth System | Sustainability: A ... View original
Is this image relevant?
3.2 Biogeochemical Cycles | Environmental Biology View original
Is this image relevant?
Biogeochemical Cycles | Microbiology View original
Is this image relevant?
Biogeochemical Cycles and the Flow of Energy in the Earth System | Sustainability: A ... View original
Is this image relevant?
1 of 3
Nutrient cycling drives ecosystem function through element movement
Carbon cycle involves CO2 fixation and organic matter breakdown
Photosynthesis by aquatic plants and algae captures atmospheric carbon
Respiration by aquatic organisms releases CO2 back into water
Decomposition of organic matter releases nutrients and CO2
Nitrogen cycle crucial for protein synthesis and DNA formation
Nitrogen fixation by cyanobacteria converts N2 to biologically available forms
Nitrification oxidizes ammonia to nitrate, denitrification reduces nitrate to N2
Phosphorus cycle often limits primary production in freshwater
Adsorption and desorption of phosphates to sediments regulates availability
Uptake by aquatic plants and algae removes phosphorus from water column
Primary production forms the base of aquatic food webs
Phytoplankton growth in open water produces oxygen and organic matter
Periphyton growth on surfaces provides food for grazers (snails, fish)
Macrophyte production in littoral zones creates habitat structure
Decomposition recycles nutrients and organic matter
Microbial breakdown of organic matter releases stored nutrients
Release of nutrients back into the water column supports new growth
Formation of detritus and sediment accumulates organic matter over time
Physical factors in aquatic biogeochemistry
Water residence time affects nutrient retention and ecosystem productivity
Longer residence times increase nutrient processing and primary production
Shorter residence times flush nutrients downstream more quickly
Stratification creates distinct layers with different chemical properties
Thermal stratification in lakes forms epilimnion, metalimnion, and hypolimnion
Chemical stratification develops oxygen gradients and nutrient distributions
Mixing redistributes nutrients and oxygen throughout water column
Seasonal turnover in temperate lakes homogenizes water chemistry
Wind-driven mixing in shallow lakes and rivers resuspends sediments
Impacts nutrient distribution and availability for primary producers
Anthropogenic impacts on freshwater biogeochemistry
Eutrophication alters nutrient balance and ecosystem function
Excess nutrient input from agricultural runoff and sewage accelerates primary production
Increased algal blooms lead to oxygen depletion in bottom waters (hypoxia )
Food web structure shifts towards dominance of planktivorous fish
Acid rain disrupts chemical balance and harms aquatic life
Decreased pH in water bodies affects organism physiology
Leaching of aluminum from soils increases toxicity to aquatic organisms
Changes in nutrient cycling and availability alter ecosystem productivity
Other anthropogenic impacts modify freshwater biogeochemistry
Dam construction alters flow regimes and sediment transport
Wetland drainage reduces natural nutrient filtering and carbon storage
Introduction of invasive species can disrupt native biogeochemical cycles
Oligotrophic vs eutrophic lake characteristics
Oligotrophic lakes have low nutrient concentrations and primary productivity
Clear water allows deep light penetration supporting diverse benthic communities
Oxygen-rich waters throughout water column
Limited algal growth results in high water clarity
Longer food chains support diverse fish communities (trout, whitefish)
Eutrophic lakes contain high nutrient concentrations and primary productivity
Reduced water clarity due to abundant algal growth limits light penetration
Oxygen depletion in bottom waters from decomposition of sinking organic matter
Frequent algal blooms can lead to fish kills and reduced biodiversity
Shorter food chains dominated by planktivorous fish (carp, catfish)
Sediment characteristics reflect trophic state
Oligotrophic lakes have low organic matter content in sediments
Eutrophic lakes accumulate high organic matter in sediments, fueling internal nutrient loading