PURPOSE:

Chlorophyll a is a photosynthetic pigment common to aquatic algae, and its measurement can provide an estimate of free-floating algae abundance in an aquatic system. For more than 40 years, the Fisheries and Oceans Canada - Great Lakes Laboratory for Fisheries and Aquatic Sciences (DFO-GLLFAS) office in Sault Ste. Marie Ontario has collected water samples for chlorophyll a spectrophotometric analysis, producing data in the form of mg/m3. The collection of chlorophyll a data was generally conducted to assist in characterizing the aquatic systems level of primary productivity, since that can influence fish abundance. This was a supplementary measure of the quality of fish habitat in these systems for a variety of fish-related projects of relevance to DFO’s mandate. Consistency of data collection was dependent on the duration of each project and funding available.

DESCRIPTION:

The initial study collected chlorophyll a data from the five lakes in the Turkey Lakes Watershed (TLW – Upper and Lower Batchawana Lakes, Wishart Lake, Little Turkey Lake and Turkey Lake) as well as Quinn Lake which is located outside of the TLW (see Smokorowski et al. 2006) in partnership with Environment and Climate Change Canada (ECCC) and Natural Resources Canada (NRCAN), as part of Canada’s Acid Rain Initiative. The TLW study was established in 1979 to evaluate the impacts of acid rain on terrestrial and aquatic ecosystems. This dataset encompasses chlorophyll a data collected from five lakes in the TLW and Quinn Lake (data also collected by the Canadian Wildlife Service and Environment and Climate Change Canada) from 1983 - 2010 with some gaps of varying duration (Webster et al., 2021). Note that an experimental habitat removal took place in some TLW lakes and Quinn Lake in 1999 and 2000. Specifically, in autumn of 1999, 50% of the coarse woody material was removed from the shorelines of Little Turkey Lake and Quinn Lake, and in autumn of 2000, 50% of the course woody material was removed from Wishart Lake shoreline (details available in Smokorowski et al., 2006).

Methods Summary:

Sampling was only conducted during the open water season and the frequency and extent of sampling frequency in each waterbody varied and was project- and funding-dependent. There are no chlorophyll a data for the years 1986, 1989 – 1990, 1996 – 1997, 2006-2007 and 2009.

Sampling was accomplished by rinsing on site an appropriately-cleaned 1 L, brown-opaque polyethylene bottles at least three times. For hand draw samples, the bottle was immersed sub-surface (less than 0.5 meters) to collect the sample. Composite tube samples were collected using an integrated water sampling tube that collected epilimnion water from the entire water column to a depth of 5 meters. Up to five - 1 L (1000 mL) samples were collected per station and returned to the lab on ice. Each 1 L sample was filtered using glass fiber filters (Whatman GF/C, 42.5 mm) within one day of sampling, and then frozen prior to standard chlorophyll a analysis (American Public Health Association [APHA] 1985). From 1983-1998, Chlorophyll a concentrations (mg/L) was calculated based on APHA 1985; from 1998 to present the calculation was based on APHA (1998).

The sample dataset information includes the georeferenced sampling locations, the raw data for chlorophyll a calculations, and the calculated chlorophyll a concentrations using both the APHA (1985) and APHA (1998) methods.

This dataset was published in partnership with the Canadian Institute of Ecology and Evolution - Living Data Project, which was funded by a CREATE grant from the Natural Science and Engineering Research Council of Canada. We would like to recognize Caroline Dallstream for her effort in publishing this dataset.

SAMPLING METHODS:

Methods Summary:

Sampling was only conducted during the open water season and the frequency and extent of sampling frequency in each waterbody varied and was project- and funding-dependent. There are no chlorophyll a data for the years 1986, 1989 – 1990, 1996 – 1997, 2006-2007 and 2009. See

Sampling was accomplished by rinsing on site an appropriately-cleaned 1 L, brown-opaque polyethylene bottles at least three times. For hand draw samples, the bottle was immersed sub-surface (less than 0.5 meters) to collect the sample. Composite tube samples were collected using an integrated water sampling tube that collected epilimnion water from the entire water column to a depth of 5 meters. Up to five - 1 L (1000 mL) samples were collected per station and returned to the lab on ice. Each 1 L sample was filtered using glass fiber filters (Whatman GF/C, 42.5 mm) within one day of sampling, and then frozen prior to standard chlorophyll a analysis (American Public Health Association [APHA] 1985). From 1983-1998, Chlorophyll a concentrations (mg/L) was calculated based on APHA 1985; from 1998 to present the calculation was based on APHA (1998).

The sample dataset information includes the georeferenced sampling locations, the raw data for chlorophyll a calculations, and the calculated chlorophyll a concentrations using both the APHA (1985) and APHA (1998) methods.

USE LIMITATION:

To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.