Zooplankton density and biomass in the Saguenay river, Québec (2013)

The density and zooplankton biomass was calculated for 22 lakes in the Boreal region. The lakes are distributed on both shores of the Saguenay in the Saguenay-Lac-Saint-Jean region. In addition, data presence / absence of fish, morphological and chemical were collected for each of these lakes. This sampling was carried out in 2013.

Personne(s) ayant accès aux données

Personne(s) ayant collecté les données

Autres institutions

We thank the Ministère du Dévéloppement durable, Environnement, Faune et Parcs du Québec for having shared their data.

Personne en chare des données

Audrey Lafrenaye

Format du jeu de données

Excel documents.

Nombre de sites

22

Description du site

For zooplankton community analysis, 22 small lakes of the boreal region have been sampled. The lakes are distributed on both shores (North and South) of the Saguenay River in the Saguenay-Lac-Saint-Jean region. Of the 22 lakes, 15 contain brook trout Salvelinus fontinalis populations while 7 lakes do not contain any fish at all (according to data provided by the respective ZECs of each lake and confirmed by data provided from the Ministère du Dévéloppement durable, Environnement, Faune et Parcs du Québec).

Environnement

Aquatique

Taxa étudiés

Zooplankton

Information taxonomique

Crustacées, Animaux invertébrés autre qu'arthropodes.

Détails taxonomiques

Nom latin	Nom anglais	Nom français

Approche expérimentale

ZOOPLANKTON SAMPLING AND IDENTIFICATION: Sampling was done between September 30 and October 9 2013. The sampling took place at the deepest point of each lake. A depth sounder was used to scout for the deepest depth. Water was collected using a 2 L Limnos at different depths along the entire water column up to a maximum of 10 meters for deep lakes. We wanted to obtain 10 L of water in total; therefore 5 Limnos samples of 2 L each were collected at different depths along the entire water column and integrated into a bucket. For example, if a lake had a maximum depth of 14 meters, samples were collected at 0, 2, 4, 8 and 10 m. If a lake had a maximum depth of 5 meters, samples were taken at 0, 1, 2, 3, and 4 m, etc. In order to avoid collecting sediments or any benthic associated zooplankton, lakes below 10 m of depth were always sampled up to a maximum of 1 m above the bottom. The integrated water samples were then passed through a 20 µm sieve. The content of the sieve was carefully washed into plastic containers and formaldehyde was added to a concentration of about 4%. This procedure was repeated 3 times in every lake in order to obtain 3 zooplankton replicates. A vertical 50 µm plankton net tow was performed once in every lake. The tows were started at a depth of 1 meter above the bottom of shallow lakes or at a depth of 10 m for deeper lakes and dragged up to the surface. The content of the net was carefully washed into plastic containers and formaldehyde was added to a concentration of about 4%. The samples collected with the 50 µm plankton net tows will be used to compare abundance and diversity data with the 20 µm mesh sieve plankton samples collected at discrete depths with the Limnos. The zooplankton was identified to major taxonomic groups for cladocerans and copepods and to the species for rotifers. A binocular microscope as well as appropriate identification keys were used for properly counting and identify zooplankton in every lake. Biomass data relative to every zooplankton taxon of every lake was calculated using the length: biomass ratio for copepods and cladocerans and the biovolume: biomass ratio for rotifers. An inverted microscope equipped with an integrated camera will be used to correctly measure the animals. WATER COLUMN PROFILE DETERMINATION: A YSI meter was used to determine the water column profile. Temperature, conductivity, pH, and oxygen concentration relative to depth was recorded for every meter starting at 0 m, up to a maximum of 10 m in deep lakes. The YSI was calibrated at every lake. CHLOROPHYLL A, TP, CDOM, AND DOC ANALYSIS: Additionally, 2 litres of the same lake water sample that was originally mixed in the bucket was collected in opaque plastic containers and brought back to the lab. 250 ml of this water was filtered through a GF/F filter. The filters were conserved in aluminum paper and stored at -80 degrees for future chlorophyll analysis. This procedure was repeated three times to obtain three chlorophyll replicates per lake. About 100 ml of water from the opaque 2 liter plastic bottle was then filtered through milliQ pre-washed filters. The filtered water was then distributed between a 25 ml vial for CDOM (colored dissolved organic matter) analysis and a 45 ml vial for DOC analysis. The CDOM analysis will be done using a spectrofluorometer to determine autoDOC and alloDOC contents of each lake. Additionaly, 25 ml of water was again taken from the opaque 2 liter plastic bottle and transferred to tubes containing a drop of acid for future total phosphorus (TP) analysis. PHYTOPLANKTON AND BACTERIA SAMPLING: In order to obtain phytoplankton and bacteria biomass measurements, water samples were taken at intervals of 1 m starting at the surface of the water column to a maximum of 10 meters for deep lakes or stopping 1 m from the bottom for shallow lakes using the 2 L Limnos. At least 10 L of water was collected. The water was then mixed in a bucket to get an integrated water sample representative of the entire water column. Once mixed, about 125 ml of the water was collected from the bucket in vials. A few drops of lugol were added to preserve phytoplankton. The procedure was repeated once for every lake. These samples will be analysed in the lab using an inverted microscope to count phytoplankton abundance in every lake. From the same bucket, 5 ml of lake water was collected into plastic test tubes in which formaldehyde was added to a concentration of 4% to measure. This procedure was repeated 3 times to have 3 replicates. These samples will be analysed in the lab using a flux cytometer to count bacteria. They are preserved in -80 degrees freezer. WATERSHED SURFACE AREA: Watershed surface area was calculated for each lake using the application ArcGIS.

Statut de l'étude

Complété

Stratégie d'echantillonnage

Échantillonnage passif (e.g. trappe à insecte ou à animal)

Objectifs de l'étude

Niveau de la communauté (e.g. richesse, distribution, composition)

Types de données

Liste d'espèces, Abondance/abondance relative/fréquence, Biomasse

Fréquence d'échantillonnage

Sampling was done between September 30 and October 9 2013.

Première année de collecte de données

2013

Dernière année de collecte de données

2013

Données