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Table 1 Detailed eligibility and exclusion criteria used to determine study eligibility in the systematic review

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

Eligibility 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 (eligible 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 validity

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 validity (e.g., methodology)

Retracted articles

  1. aWe included some search terms that may capture studies in lentic habitats related to flowing systems (e.g., floodplain, riparian) in an attempt to obtain eligible studies that might otherwise be missed. We recognize that there is some uncertainty with the lotic/lentic distinction (e.g., flowing freshwater springs) and liberally included such articles at the title/abstract screening if otherwise eligible