Search results
Results from the WOW.Com Content Network
However, when the mixed layer becomes shallower than the critical depth, enough of the phytoplankton remain above the compensation depth to give the community a positive net growth rate. Sverdrup’s model is a cause and effect relationship between the depth of the mixed layer versus the critical depth and the bloom of phytoplankton.
Phytoplankton (/ ˌ f aɪ t oʊ ˈ p l æ ŋ k t ə n /) are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems.The name comes from the Greek words φυτόν (phyton), meaning 'plant', and πλαγκτός (planktos), meaning 'wanderer' or 'drifter'.
Phytoplankton growth rate is very intense and short lived in open areas surrounded by sea ice and permanent sea-ice zones. Grazing by herbivores such as krill, copepods and salps is believed to suppress phytoplankton standing stock.
The difference between intracellular and extracellular CO 2 concentrations reflects the CO 2 demand of a phytoplankton cell, which is dependent on its growth rate. The ratio of carbon demand to supply governs the diffusion of CO 2 into the cell, and is negatively correlated with the magnitude of the carbon fractionation by phytoplankton. [34]
Shifts in the dominant phytoplankton species are likely caused by biological and physical (i.e. environmental) factors. [2] For instance, diatom growth rate becomes limited when the supply of silicate is depleted. [1] [2] [17] Since silicate is not required by other phytoplankton, such as dinoflagellates, their growth rates continue to increase.
The central argument for the critical depth hypothesis is that blooms are a consequence of increased phytoplankton growth rates resulting from shoaling of the mixed layer above the critical depth. The critical depth is a surface mixing depth where phytoplankton biomass growth equals phytoplankton biomass losses. In this hypothesis, losses are ...
Redfield discovered the remarkable congruence between the chemistry of the deep ocean and the chemistry of living things such as phytoplankton in the surface ocean. Both have N:P ratios of about 16:1 in terms of atoms. When nutrients are not limiting, the molar elemental ratio C:N:P in most phytoplankton is 106:16:1. Redfield thought it wasn't ...
Depending on the predation rate, they could express regular or chaotic behavior. [69] A negative effect that fish larvae can have on planktonic algal blooms is that the larvae will prolong the blooming event by diminishing available zooplankton numbers; this in turn permits excessive phytoplankton growth allowing the bloom to flourish . [53]