Monitoring Update April 1, Northeast Aquatic Research George Knoecklein Hillary Kenyon Sabina Perkins

Transcription

1 Monitoring Update April 1, 215 Northeast Aquatic Research George Knoecklein Hillary Kenyon Sabina Perkins

2 Lake Monitoring Approach for 214 Tonight's discussion will focus on in-lake aspects: Assessment of nutrient levels, water clarity, Dissolved oxygen naiad growth, other native plants, Search for remaining fanwort beds A future discussion will focus on watershed aspects

3 Lake Visits 214 Station 1 Deep water = Top, middle, bottom Station 2 Shallow water = Top, bottom Outflows from Middle, Upper, and Lower Bolton Lake Several inlets around the two lakes were monitored 1

4 Brief history of LBL 1. WQ data collected in April and September 1979 by CAES 2. Deep (6-7 inches) drawdowns of Middle Bolton Lake during winters of 26-7, 27-8, and 28-9 (see next) 3. WQ collected on July 27, 211; and July 3 212; by NEAR 4. In 211, NEAR mapped acres of floating naiad (see following) 5. Bloom of blue-green algae in late August 212 Clarity declined from 4 m in early July to.5 m in late August NEAR started frequent lake samplings on August 27, Sonar herbicide applied May 3, Follow-up Sonar booster and copper sulfate applied to deeper water on June 27, 213

5 Winter Water Level Drawdown of Middle Bolton Lake Middle Bolton Lake Levels During Deep Drawdowns Water Level Down (in)

6 Southern Naiad in Lower Bolton Lake July 27, 211 Similar, if not worse, conditions existed in 212

7 Nutrient levels Important nutrients are: Phosphorus Nitrogen Ammonium Nitrate Organic (that is nitrogen bound in carbon bonds) All other requirements that plants and algae have are readily available

8 Limiting Nutrient Concept When all growth requirements are met except one than growth will depend on the availability of that one missing factor Element Plant Content % Average Supply % Ratio of content to supply Oxygen Hydrogen Carbon , Silicon , Nitrogen , Phosphorus.8.1 8, Potassium ,3

9 Lake 226 Northwest Ontario ~1968 N & C only N, C, and P

10 CT DEP trophic categories and paired T Phosphorus And Water Clarity 12 Oligotrophic 1 Secchi Disk Depth (m) Highly Eutrophic TP (ppb) 1

11 And even more phosphorus vs water clarity data 25 15,233 data points from Maine Lakes Monitoring Program 2 Secchi disk depth in meters 15 1 y =.3212x R² = Phosphorus - as mg/l

12 Total phosphorus trends in LBL meter 3 meters 5 meters 6 TP - ppb Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan months

13 Phosphorus at two stations meter Station 1 Station 2 4 TP - ppb Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan months

14 More phosphorus at two stations meters Station 1 Station 2 TP - ppb Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan months

15 6 Analysis of phosphorus differences at two stations Station y =.8512x R² = Station Station Station 1

16 Phosphorus in deep water at Station TP y =.383x R² = meters meters

17 Total Nitrogen in LBL m 3 m 5 m 15 TN - ppb 1 5 Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan months

18 Total Nitrogen at two stations 12 Station 1 1 Station 2 8 TN - ppb meter Jan Apr Jul Oct Jan Apr Jul Oct Jan months

19 More total nitrogen at two stations 12 1 Station 1 Station 2 8 TN - ppb meters Jan Apr Jul Oct Jan Apr Jul Oct Jan months

20 Total Nitrogen at 3 and 5 meters 25 Station meters meters

21 Water temperature, dissolved oxygen, and water clarity Water temperature shows the degree and position of any stratification Dissolved oxygen shows location of anoxic water and super-saturation Water clarity gives the indication of water column phytoplankton or other suspended material

22 Water Temperature Water Temperature o C Surface Bottom 5.. Jan Apr Jul Oct Jan Apr Jul Oct Jan Months

23 Position of a Thermocline in LBL Thermocline location -meters below surface Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months

24 Anoxic Boundary in LBL Position of Anoxic boundary in meters below surface Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months

25 LBL water clarity history.5 1 Secchi Disc Depth - meters /3/11 9/2/11 3/3/12 9/2/12 3/4/13 9/3/13 3/5/14 9/4/14

26 Water clarity in LBL Secchi Disk Depth in meters Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months

27 Phosphorus / Water Clarity revisited 12 Oligotrophic 1 Secchi Disk Depth (m) Highly Eutrophic TP (ppb) 27

28 Summary Both Phosphorus and Total Nitrogen are trending down Water clarity has improved Dissolved oxygen has improved Location of LBL on the phosphorus / clarity model shows LBL was essentially a different lake in 214 over 213 Internal phosphorus loading is evident in 213, much less so in 214 Internal nitrogen loading severe in 213 but much less so in 214 Evidence suggests that surface phosphorus is differ may be influenced by sources other than deep water

29 Aquatic plant 214 survey results Very little southern naiad in the lake note blue areas on the map. Large beds of macroalgae were found along most of the east and north shores Other natives are also returning No Fanwort found in the lake during 214

30 Creeping Normalcy Perhaps the commonest circumstance under which societies fail to perceive a problem is when it takes the form of a slow trend concealed by wide up-anddown fluctuations - Jared Diamond Collapse