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Nutrient cycle is more often used in direct reference to the idea of an intra-system cycle, where an ecosystem functions as a unit. From a practical point, it does not make sense to assess a terrestrial ecosystem by considering the full column of air above it as well as the great depths of Earth below it.
When an ecosystem experiences an increase in nutrients, primary producers reap the benefits first. In aquatic ecosystems, species such as algae experience a population increase (called an algal bloom). Algal blooms limit the sunlight available to bottom-dwelling organisms and cause wide swings in the amount of dissolved oxygen in the water.
Production is limited by the availability of nutrients, most commonly nitrogen or iron. Numerous experiments [8] have demonstrated how iron fertilization can increase phytoplankton productivity. Nitrogen is a limiting nutrient over much of the ocean and can be supplied from various sources, including fixation by cyanobacteria.
It may even be the case that the Redfield Ratio is applicable to terrestrial plants, soils, and soil microbial biomass, which would inform about limiting resources in terrestrial ecosystems. [12] In a study from 2007, soil and microbial biomass were found to have a consistent C:N:P ratios of 186:13:1 and 60:7:1, respectively on average at a ...
In some coastal marine ecosystems, research has found nitrogen to be the key limiting nutrient, driving primary production independently of phosphorus. [ 17 ] [ 18 ] Nitrogen fixation cannot adequately supply these marine ecosystems, because the nitrogen fixing microbes are themselves limited by the availability of various abiotic factors like ...
The seminal synthesis by Geider and La Roche in 2002, [101] as well as the more recent work by Persson et al. in 2010, [102] has shown that C:P and N:P could vary by up to a factor of 20 between nutrient-replete and nutrient-limited cells. These studies have also shown that the C:N ratio can be modestly plastic due to nutrient limitation.
Low-nutrient, low-chlorophyll (LNLC) regions are aquatic zones that are low in nutrients (such as nitrogen, phosphorus, or iron) and consequently have low rate of primary production, as indicated by low chlorophyll concentrations. These regions can be described as oligotrophic, and about 75% of the world's oceans encompass LNLC regions.
In lakes, phosphorus and nitrogen are the most common limiting nutrients of primary production and ecosystem respiration. Foundational work on the positive relationship between phosphorus concentration and lake eutrophication resulted in legislation that limited the amount of phosphorus in laundry detergents , among other regulations.