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Table 4 Detailed inclusion and exclusion criteria used to determine study inclusion in the systematic review

From: Response of chlorophyll a to total nitrogen and total phosphorus concentrations in lotic ecosystems: a systematic review protocol

Inclusion criteria Exclusion criteria
Population (unit of study)a
 –Lotic fresh waters anywhere in the world;
 –Mesocosms made to mimic lotic freshwater systems.
–Lentic or non-fresh waters (wetlands, lakes, reservoirs, ponds, oceans, estuaries)
Exposure (environmental variable to which population is exposed)
 –Exposure to total nitrogen (TN) or total phosphorus (TP) measured as concentration (e.g. mg/L) –Exposure only to other nutrients, or nitrogen and phosphorus not reported as TN or TP
Comparators (control or alternative intervention)
 –Comparison to sites or treatments with lower or higher levels of TN or TP across a gradient;
 –Comparison to control group (no or background TN or TP) or to lower or higher levels of TN or TP in experimental studies.
–Studies of single sites (without sampling across time) or those without comparison to lower or higher levels of TN or TP.
Outcomes (relevant outcomes resulting from exposure)
 –Concentration of benthic or sestonic chlorophyll a, measured as mass per area or volume (e.g. µg/cm2, mg/m2, µg/L) –Studies examining only TN or TP with no data on biological responses;
–Studies examining other biological effects
Study type
 –Experimental studies in mesocosms or field sites;
 –Field-based, observational studies
–Studies examining only TN or TP with no data on biological responses;
–Studies examining only biological effects other than chlorophyll a
Publications (types of sources used)
 –Study must contain original data;
 –Study must contain sufficient detail on methodology to assess study quality
–Articles with no original data (e.g. editorials, reviews);
–Articles without sufficient information to evaluate pertinent relationships (chlorophyll a response to TN or TP) or study quality (e.g. methodology);
–Retracted articles
  1. a We included some search terms that may capture studies in lentic habitats related to flowing systems (e.g. floodplain, riparian) in an attempt to obtain relevant studies that might otherwise be missed. We recognize that there is some uncertainty with the lotic/lentic distinction (e.g. flowing freshwater springs) and will liberally include such articles at the title/abstract screening if otherwise relevant