BIOINDICATION

IN AQUATIC ECOSYSTEMS

Periphyton

Periphyton as indicatorsPeriphyton are used as indicators of

environmental condition because they respond rapidly and are sensitive to a number of anthropogenic disturbances, including:habitat degradationnutrient enrichmentmetalsherbicideshydrocarbonsacidification

Periphyton Biomass Measurements

Ash-Free Dry Weight

Pigment Analysis

Biovolume Measurement

Periphyton – Sampling methodsOne way to scrape a

known area is to lay a plastic 35 mm slide (film removed) over the rock and scrape off the material within the slide area

scrub area = 2.3cmX3.5cm=8cm2

Rocks don’t always look like they have much on them

Nearly all the stuff scrubbed off this one was organic matter –most of it living algaeS.Loeb and J.Reuter images

Periphyton – Sampling methods

Material from a rock scrub contains macro and micro invertebrates, detritus, fungi, bacteria, as well as algae

Periphyton – in situ sampling

Periphyton – III. Preservation methods Lugols’s iodine can used if the algae of

interest are soft bodied forms (i.e. blue-greens and green algae).

If interested only in diatoms, it may be best to preserve in 70% ethanol.

Freeze sediment samples if they are to be analyzed for surficial chlorophyll.

Here’s a portion of the previous sample after being deposited on a glass fiber filter in preparation for chlorophyll extraction or AFDW determination.

Periphyton – sample prep

Periphyton – pigment analysis

Chlorophyll extraction:Tear filter into several piecesPlace in a test tubeAdd 10 mLs of 90% acetoneExtract overnight at 4oC

Chlorophyll analysisAfter 18-24 hr extraction,

centrifuge to settle filter debrisRead absorbance or

fluorescence of the supernatant

Periphyton – biomass estimation • Wet weight

• Dry weight (dried at 103–105 oC)

• Ash free dry weight (AFDW)

• Loss on ignition (LOI)

• Combust at 475-550 oC

• Chlorophyll (extract as per phytoplankton)

• Particulate organic carbon and/or nitrogen (POC or PON)

Muffle furnace

Project NameWater Quality Samples scrub area = 2.3cmX3.5cm=8cm2

2002 8 cm2=0.0008 m2 X 3 scrubs = .0024 m2 total areaNRRI Central Analytical Labemr 12/4/02

Sample Run chlorophyll phaeophytin volume total chlorophyllPeriphyton Date Date ug/L ug/L filtered (mLs) volume (mLs) mg/m2Whatever Creek 5/6/2002 5/15/2002 130 60 45 45 2.4

Sample Run Dry Wt AFDW total volume AFDWDate Date mg/L mg/L volume (mLs) filtered (mLs) g/m2

Whatever Creek 5/6/2002 5/8/2002 156 117 319 122 6.0

chlorophyll

AFDW

Once you have a measure of chlorophyll or AFDW you’ll need to calculate per unit area.

Periphyton – biomass calculations