We collected zooplankton with a 243 um (micron) net. This means the mesh size of the net is 243 microns or 0.243 millimeters. The abbreviation for micron is the Greek symbol mu (I don’t know how to do that in WordPress!) followed by an “m.” This is an important detail, because it means we only sampled the “macrozooplankton” community. There are plenty of species smaller than 243 um that we did not sample.
We used a YSI 550 dissolved oxygen meter to measure temperature and dissolved oxygen. Both temperature and oxygen were measured directly below the water’s surface.
This Microsoft Excel file contains our zooplankton, temperature, oxygen, and Secchi depth data: JordanLake_2010-11_data.
Despite some discrepancies in the data (see the “compare” sheet), your non-expert zooplankton counting is sufficient for identifying trends in Daphnia lumholtzi vs. the native zooplankton over time. Good work, everyone! See the updated spreadsheet here.
I still have not counted the rest of the November samples, but here is the spreadsheet with native cladoceran and copepod data (the two major zooplankton groups) for each date.
I still need to count reps 2-4 from the Nov. 13 samples, but here is a comparison between the class data and my data so far. I am impressed with how close our counts are! Remember that we would expect my recounts of your replicates to be a little lower due to possible loss of animals as samples are pipeted and transferred multiple times. I inserted comments in some cells in row 9 to note how many Asplanchna I found (some of you may have counted Asplanchna as native zooplankton, but I think most of you did not). It appears the main discrepancy in our data is ephippia on Sept. 18.
As you begin your research note project, you may be wondering about the field notes for the first three data points – the zooplankton data I collected over the summer. Here are a few important notes regarding those data:
- The July 19 data were actually collected from a different location in Jordan Lake: the Vista Point boat ramp. This is located near the southwest portion of the lake, closer to Pittsboro.
- I did not have a DO/temperature meter or Secchi disk for July 19, Aug 5, or Aug 23. However, Jordan Lake surface water temperature data for those dates are available here. If you use the temperature data for your report, don’t forget to convert to degrees Celsius.
- I used the same 243 micron zooplankton net to collect samples.
- Weather/ notes for July 19: sunny, hot, very windy. Wind blowing parallel to the shore. Sampled ~8:30 am.
- Weather/ notes for Aug 5: very windy (into the dock); hazy, but breaking up. ~mid-80s. Sampled ~9 am
- Weather/ notes for Aug 23: light breeze, but mostly calm; mid-upper 80s; partly cloudy. Sampled 10-11 am.
Lastly, here are a few links that may be useful for your research note:
Jordan Lake – Nov. 13, 2010
Starting time: 10:00 am
Weather Conditions: Sunny, no cloud coverage, light breeze, low 50′s
Reps:
1.) 2.5m (Prof. Cooke)
2.) 2.5m (Mike)
3.) 2.5m (Shane)
4.) 1.5m (Haley)
Dissolved Oxygen: 95.9% saturation, 9.93ppm
Temperature: 13.9% C
Boating Traffic: One motorboat
Secchi Depths:
1.) 0.6m (Drew)
2.) 0.58m (Hanna)
3.) 0.7m (Max)
End time – 10:14am
Here is the file containing our complete Daphnia lumholtzi dataset JordanLake_2010_zoop_Nov13. Please download it, as you will need this for your research note writing assignment! We’ll discuss the data in class.
Here is our spreadsheet with the data from Oct 16 added: JordanLake_2010_zoop_Oct16. There was a great deal of sediment in the samples, which made counting difficult. Most groups had clumps of sediment left in their sample cups, which probably contained some zooplankton – I found a few D. lumholtzi individuals when I looked through the sediment dregs of one group’s cup. So, please consider this data point preliminary, because I plan to count the other two replicates as a form of “quality control!”
Some other important notes:
- it seemed that most of the native zooplankton was comprised of Asplanchna (see photo).
- in September the dominant native species was Diaphanosoma, but I don’t think we saw any this time (Oct students, is this correct? See the picture in your packet)
Please note in your comments anything you saw that you think might be noteworthy!
Jordan Lake
October 18th, 2010
time started: 9:50am
weather: sunny, 0% cloud coverage, mid 50, windy, the wind seemed to be from the west based on the sun’s position and water current (actually WNW from the past weather report), the wind was blowing perpendicular to the dock where we sampled
minimal boating traffic – 2 boats
rep 1: 2.6m
rep 2:2.7m
rep 3:2.8m
rep 4:2.7m
Secchi depth:
0.5m
0.5m
0.5m
temperature: 19.7° C
dissolved O2: 8o.2%, 7.3 mg/L
time ended: 10:10am