# What is critical depth for phytoplankton?

## What is critical depth for phytoplankton?

One way to define the critical depth is the depth is the depth above which depth-integrated daily gross photosynthesis equals the depth-integrated respiration, where respiration includes biomass removal by phytoplankton respiration and by grazers.

## What happens to phytoplankton below compensation depth?

The depth at which primary production equals respiration is called the compensation depth. Above this depth, phytoplankton can make a living; below this depth, they cannot and either die or go into a resting stage to await better light conditions. They can live but cannot grow or reproduce.

What is mixed layer depth?

The temperature criterion used in Levitus (1982) defines the mixed layer as the depth at which the temperature change from the surface temperature is 0.5 °C. Rather, the mixed layer depth estimated from hydrography is a measure of the depth to which mixing occurs over the course of a few weeks.

What limits phytoplankton blooms?

Phytoplankton Growth Rate. Limited supplies of light or nutrients can slow or stop cell division, preventing bloom formation. Nitrogen and phosphorus are the nutrients most likely to be in short supply relative to demand, and by Liebig’s law of the minimum, are the primary growth-limiting nutrients.

### What is normal depth?

Normal depth is the depth of flow in a channel or culvert when the slope of the water surface and channel bottom is the same and the water depth remains constant. Normal depth occurs when gravitational force of the water is equal to the friction drag along the culvert and there is no acceleration of flow.

### What is the difference between normal depth and critical depth?

Normal depth is the depth of flow that would occur if the flow was uniform and steady, and is usually predicted using the Manning’s Equation. Critical depth is defined as the depth of flow where energy is at a minimum for a particular discharge.

What is the result of the mixed layer depth rising above the critical mixing depth?

Sverdrup’s research results suggested that the shoaling of the mixed layer depth to a depth above the critical depth was the cause of spring blooms.

What is the difference between the compensation depth and the critical depth?

In Sverdrup’s words, the compensation depth is defined as the depth at which the energy intensity is such that the production by photosynthesis balances destruction by respiration. The critical depth is the depth above which daily integrated net production is zero.

## What is the difference between the mixed layer and the thermocline?

The mixed layer is near the surface where the temperature is roughly that of surface water. In the thermocline, the temperature decreases rapidly from the mixed layer temperature to the much colder deep water temperature.

## What is layer depth?

The depth from the surface of the sea to the point above the first major negative thermocline at which sound velocity is maximum.

What triggers phytoplankton bloom?

More generally, a bloom can be considered as a phytoplankton population explosion-blooms occur when sunlight and nutrients are readily available to the plants, and they grow and reproduce to a point where they are so dense that their presence changes the color of the water in which they live.

What happens to phytoplankton once they bloom?

After the bloom is over, the phytoplankton organisms die and undergo decomposition, a process that also removes DO from the water column. During some blooms, fish are seen gasping at the surface for oxygen and this lack of DO can be a direct cause of “fish kills” observed on the scene.

### How deep is the critical depth of phytoplankton?

For a day in late spring (1 May 1953), with Ed (0) « 170 W m~2, daylength « 15 h, Kd = 0.43 m_1, and the phytoplankton (predominantly the diatom, Asterionella) having Ek = 6.3 W m~2, and p = 0.033, we may calculate that the critical depth was about 177 m.

### Is phyto-plankton growth possible in the Esthwaite?

In the much shallower Esthwaite Water (zmax = 15 m), in contrast, he concluded that phyto-plankton growth should be possible throughout the year. Even in shallow water bodies, if the attenuation is high enough the circulation depth can exceed the critical depth. For turbid Lough Neagh

Is there phytoplankton in Lake Windermere in winter?

For Lake Windermere in midwinter, on the other hand, with daily incident light down to a small fraction of the summer value and circulation through the full depth of the lake, Talling (1971) estimated that phytoplankton growth was impossible.

Do winter monsoons promote phytoplankton growth?

During the winter monsoon period, nutrients were upwelled to the shallower ocean surface, and may enhance phytoplankton growth.