Long Term Experiments

High-marsh invertebrate densities for Rowley River tidal creeks associated with long term fertilization experiments, Rowley and Ipswich, MA.


Density (individuals per m2) of epibenthic invertebrate (on the surface such as snails and amphipods)  for Rowley River tidal creeks associated with long term fertilization experiments, Rowley and Ipswich, MA. 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.  Marsh fertilization from 2004 - 2016 at Sweeney Creek and 2005, and 2009-2016 at Clubhead Creek. Nutrient enrichment ended in 2016.

Core Areas: 

Data set ID: 



Short name: 


Data sources: 



All samples taken in summer no sooner than late June and no later than mid-September. In the field, 10 quadrats (0.0625 m2) were haphazardly tossed in  high-marsh area of the marsh (area dominated by Spartina patens and Distichlis spicata). Quadrats were at least 5 m from any transition zones and from each other. Grass was clipped to sediment surface . Two workers worked from the sides to collect all benthic invertebrates. Fast-moving species that escaped were enumerated.  For the amphipod, Orchestia grillus, body color was noted as an orange color indicates parasitism by the trematode Levinseniella byrdi.

Reference creeks are West and Nelson
Nutrient Enriched creeks are Sweeney and Clubhead.  Sweeney has been fertilized every summer from  2004-2016 . Clubhead had been fertilized in  2005 and then from 2009-2016.

Fish reduction
In 2009, a block net was placed in some creeks to reduce the density of mummichogs, Fundulus heteroclitus. These are the 'low fish' treatments.

All creeks have two branches determined by direction at confluence while facing upstream (Left or Right).  Samples were not collected in West-Left after 2019 due to restricted access.


Version 01: 08 October 2021, New data and metadata. Used MarcrosExportEML_HTML (working)pie_excel2007_Jul2021.xlsm 7/26/2021 9:04 AM for QA/QC to EML 2.1.0.


Subscribe to RSS - Long Term Experiments