Benthic algae chlorophyll measurements for Rowley River tidal creeks associated with long term fertilization experiments, Rowley and Ipswich, MA.


Benthic chlorophyll measurements of surface sediments (top 0-2cm) from a variety of habitats in saltmarsh tidal creeks of the Rowley River, Rowley and Ipswich, MA. Habitats include: mudflat, filamentous algae, tall Spartina alterniflora,  short Spartina alterniflora and Spartina patens zones. The TIDE project aims to simulate eutrophication on a large scale by the addition of  NO3-   aiming to reach 70μM concentrations from May to September every year during the growing season.  This fertilization of the marsh has been going on at Sweeney Creek since the 2004 growing season through 2016 and at Clubhead Creek in 2005 and  then from 2009 till 2016. Years 2017-2018 are recovery years, when fertilization was stopped.

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Benthic Algae (Chlorophyll A) Sampling Protocol for TIDE

Frequency: Monthly, May thru September
Field Equipment (stored in the TIDE benthic algae tool box):
50 ml syringes with tips cut off, knives, rulers, labeled 50 ml centrifuge tubes, extra labels and centrifuge tubes, pencil
At each plant transect collect the following number of samples in each habitat: 3 mudflat (MF), 3 filamentous algae (FA), 3 tall creekbank Spartina alterniflora (TSA), 3 Spartina patens (SP), 3 short Spartina alterniflora (SSA). 

Collect samples at low tide in order to access mudflat, filamentous algae, tall creekbank S. alterniflora and S. patens. , FA, and TSA habitat types.
Use transect as guideline for picking sample locations, but do not work directly along the transect line.
Choose general sampling location and toss syringe to “haphazardly” pick exact spot.

To collect sample: slowly push down syringe while pulling up on the plunger (try not to compress the sample). Try to get as far down as possible and then slowly pull the tube out of the substrate. Pull the plunger out and stick it into the opposite end of the syringe. Using ruler to measure, push out 2 cm of sample into the appropriately labeled centrifuge tube. (Be careful to measure two centimeters as carefully as possible each time. Calculations of chlorophyll after analysis assume equal volumes of sediment in each sample.)

MF: Take sample in exposed horizontal mud flats along creek channel during low tide. Avoid inserting syringe into an area with root masses and fibers, it is generally very easy to sample in the mud flats.
FA: Take sample along creek wall below TSA roots layer in the obvious filamentous algal zone.
TSA: Same as mudflats.
SP & SSA: Sampling is more difficult, because of the dense roots. Cut around cylinder with knife as you are inserting syringe into ground. Once syringe is inserted far enough cut a cone shape underneath syringe with knife and pull out syringe at an angle in order not to lose the sample.
Collection takes about a half day per creek with two people.
Once samples are collected, wipe off as much mud on the outside of the tubes and store in labeled plastics bags. Samples must remain frozen until analysis.

Step 1: Extraction (typically done in the pm the day before analysis on spectrophotometer)

50-ml polypropylene centrifuge tubes containing sample (frozen and in the dark)
100% acetone
90% acetone
Coolers with ice
Latex (non-nitrile) gloves

Chlorophyll degrades easily. As much as possible, keep samples cool and dark.
Work in a hood to minimize your exposure to acetone fumes and cap samples tightly when not in use. Acetone eats many plastics so be mindful of the materials you are using
to store and transfer samples. Acetone will also wash away sharpie- so keep track of sample numbers and protect your labels. Avoid using acid-washed equipment to
minimize potential acid-contamination of samples. Length of extraction should be around 16 hours, so plan to time your sample prep and analysis accordingly. Prep only
the amount of samples you can feasibly analyze in one sitting. Usually no more than 40- 50 samples at a time.

Prep samples with acetone:

1. Allow samples to thaw at room temperature for about two hours before putting in coolers. Samples should be thawed, but cool to the touch.
2. Clean any excess mud off of sample containers and transfer thawed samples to coolers with ice
3. Store acetone solution in coolers on ice
4. Under hood, use a re-pippeter to add 25mls of 100% acetone to each tube
5. Shake each sample vigerously by hand to break up sediment at the bottom of each tube
6. Place tubes back on ice in cooler. Samples maybe sonicated or shock chilled to further break algal cells.
7. Centrifuge sample prior to reading on the spectophotometer.

Reference creeks in all years are West and Nelson
Nutrient Enriched creeks are Sweeney and Clubhead.
Sweeney was fertilized every summer from  2004-2016.  Clubhead was fertilized in  2005 and then from 2009-2016.

All major creeks have two branches determined by direction at confluence while facing upstream (Left or Right).   

Plant transects run perpendicular to  creeks at various points with a front pole at the creek bank and a back pole an the high marsh. Transects are in the order of 1, 2, 4, 3 or blue, green, red, yellow from confluence of branch.

MF= Mud Flat

TSA= Tall Spartina alterniflora

SP= Spartina patens

SSA=Short Spartina alterniflora

FA= Filamentous algae


Version 01: January 27, 2012, updated data and metadata. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 1/18/12 4:51 PM for QA/QC to EML 2.1.0.

Version 02: June 20, 2013, data and metadata updated to comply with importation to Drupal and LTER PASTA. Research location name and description updated.Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 3/14/13 12:02 PM for QA/QC to EML 2.1.0

Version 03: August 1, 2019, data and metadata updates to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007_Jun2019.xlsm 6/7/19 12:58 PM for QA/QC to EML 2.1.0

Version 04: August 2. 2019 updated publication date to reflect date of new data submission


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