---
title: "Phytoplankton Data Fields | Definitions"
slug: "phytoplankton-data-fields"
description: "Learn the data inputs and appropriate datafile format for phytoplankton when using the water quality solver. "
tags: ["1D river modelling"]
updated: 2022-08-05T06:33:42Z
published: 2022-08-05T06:33:42Z
canonical: "help.floodmodeller.com/phytoplankton-data-fields"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.floodmodeller.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Phytoplankton Data Fields

## Data Input

**I** n order to input the required information for this pollutant into the Water Quality model, the user needs to make sure that the Tab Phytoplankton appears in the WQ General Tab (please follow the description on the page [Preparing a Water Quality Datafile](/v1/docs/preparing-a-water-quality-datafile) for this). Then the user needs to select the Tab Phytoplankton and type in the necessary information for this pollutant in the fields which are shown on this Tab. Alternatively the necessary information for this pollutant can be typed in the .con file opened in a Textpad editor in the datafile format mentioned below.

## Datafile Format

Line 1 PHYTOPLANKTON

Line 2 knutrient, kPH, kS, rphtn, rphtp, rphts

Line 3 gr1p, cinc1p, gr2p, cinc2p, tcrit

Line 4 slmxph, extpht, rpht20, q10pht, dethph

Line 5 dcdcay, alphdc, vdcset

Where:

PHYTOPLANKTON = keyword

knutrient= half saturation constant for nitrate uptake (mg/l)

kPH= half saturation constant for phosphate uptake (mg/l)

kS= half saturation constant for silicate uptake (mg/l)

rphtn = nitrogen to carbon ratio

rphtp = phosphorus to carbon ratio

rphts = silicon to carbon ratio

gr1p = maximum productivity (loge(Pmax) = mT+c) parameters: gradient below TCRIT

cinc1p = maximum productivity (loge(Pmax) = mT+c) parameters:intercept below TCRIT

gr2p = maximum productivity (loge(Pmax) = mT+c) parameters: gradient above TCRIT

cinc2p = maximum productivity (loge(Pmax) = mT+c) parameters: intercept above TCRIT

tcrit = maximum productivity (loge(Pmax) = mT+c) parameters: TCRIT(oC)

slmxph = Solar radiation for maximum productivity (kJ/cm2/hour)

extpht = light extinction factor due to phytoplankton

rpht20 = respiration rate at 20C (day-1)

q10pht = Q 10 value for respiration of phytoplankton

dethph = mortality rate constant for phytoplankton (day-1)

dcdcay = Detrital carbon parameters: decay constant at 20C (day-1)

alphdc = factor for temperature dependence

vdcset = settling velocity for detrital carbon (mm/s)

---

Overview

[Phytoplankton](/v1/docs/phytoplankton)