1 There are openings thru UTSC. Contact Professor Cyr if interested!Aquatic Ecology IV 402 Ramsay Wright I suspect we won’t get through all our slides. If you are interested in this type of material, consider the field course (EEB410H: Lake Ecosystem Dynamics) offered Aug 2010 at the Harkness Fisheries Research Lab, Algonquin Park There are openings thru UTSC. Contact Professor Cyr if interested!

2 Mon: physical limnology Wed: chemical limnology (bioassay hypothesis) Past weeks Mon: physical limnology Wed: chemical limnology (bioassay hypothesis) Mon: primary/secondary producers, tri/quad-trophic interactions, intro to Scavia et al. Today: Case study day: Scavia et al. + Lake Simcoe , the Aral Sea, (Red/Dead Seas) and the Grand Canal or what we have time for!

3 On Monday we looked at the 5 primary changes in the Lake Michigan ecosystemRecall that on the basis of observational data alone, we can’t differentiate bottom-up from top-down driven change so the primary hypothesis of Scavia et al.: Alterations in phytoplankton assemblies and zooplankton species composition were caused either by (1) reduced P loading and/or (2) reduced predation on large zooplankton due to declining alewife abundance

4 Why do we care? Phosphorus removal strategies are expensive.How did “sports fishing” become a key value for the Great Lakes? – see the Meisenheimer article off the web page Why do we care? Phosphorus removal strategies are expensive. Salmonid stocking rates depend on planktivore abundances Salmon contribute significantly to the value of the Great Lakes recreational fishery (350 million in Ontario annually or $7.4 billion.y-1 to 8 Great Lakes states and the provinces of Ontario and Quebec)

5 Authors ‘tested’ hypotheses by:Constructing a model of phytoplankton-zooplankton-nutrient interactions, Calibrating it to conditions observed in the 1980s and Subjecting it to a range of planktivore predation (zooplanktivory) under the influence of 2 P-loading scenarios. Seeing if they could recreate the conditions of the 1970s

6 Anecdotal model Si P diatoms flagellates blue-greens sink diaptomusdaphnia (Fig. 1) alewife

7 Modeling available phosphorusP = BAP or biologically available P PC =[P]/[C] rZ = zoo respiration B= unassimilated food E = zooplankton poop µA = phytoplankton production m = mineralization rate Table 1

8 Modeling phytoplanktonA = [phytoplankton]  = growth rate s = settling loss (sinking/zepi) g = zoo grazing Z = [zooplankton] Table 1 + text

9 Modeling Zooplankton Table 1 + text Z = [zooplankton] g = grazingr = respiration rate P = fish predation Table 1 + text

10 The simulation analysis tests whether the model, calibrated to conditions and species mixtures of the 1980s, cladocerans and phytoflagellates, can reproduce the trend (backwards in time) to the mid-1970s (a summer complex comprised of copepods and blue-greens)

11 Table 4: 83-84 measured epilimnial conditionsAlgal growth rates Algal production Algal biomass Algal sinking Zooplankton grazing Zooplankton biomass d.d-1 12.9 ± 2.2 µg C.L-1.d-1 µg C.L-1 (green/crypto dominance) µg C-1.d-1 8.7 ± µg C.L-1.d-1 µg C.L-1 (Daphnia dominance)

12 Alewife abundance is a surrogate for time!Model output: Figure 4 Alewife abundance is a surrogate for time!

13 Alewife abundance (1000 MT)Irrespective of phosphorus load (low or high) the model predicts: Daphnia dominate at low alewife numbers Diaptomus dominate under high alewife numbers High P The model isn’t perfect (but not bad!) Low P Total zooplankton Fig. 4A Zooplankton (ug C.l-1) daphnia diaptomus The 1980s The 1970s Alewife abundance (1000 MT) 15

14 Fig. 4B Irrespective of phosphorus load (low or high):Flagellates remain relatively constant despite alewife numbers Blue-greens (and hence total phytoplankton) increase at high alewife numbers High P total Low P flagellates Fig. 4B Phytoplankton (ug C.L-1) The 1980s blue-greens The 1970s diatoms Alewife abundance (1000 MT) 15

15 Conclusions: While Lake Michigan phytoplankton (and transmissivity) responded to the ~35% reduction in P-load between the 70s and 90s, the response to altered zooplanktivory was stronger. In Lake Michigan, the role of large Daphnia is critical

16 “While we have evaluated the importance of nutrient loading and food web interactions as a dialectic, that approach may be less constructive than a hierarchical one:” Nutrient loading obviously determines the basic trophic state of a system. However, within the boundaries set by nutrient load, food-web interactions are important in regulating the composition of the plankton community. A partial answer to the question we posed in our 1st lecture: Is water quality more likely to respond to watershed phosphorus control or in situ rehabilitation of piscivore populations?

17 The future as seen in 1984: An invasive, invertebrate predator, Bythotrephes cederstroemi reported in Lake Michigan. Invertebrate predation can also have important consequences for plankton community structure. So, Scavia et al. add an invertebrate predator to the model.

18 A predatory zooplanktor that feeds on grazing (herbivorous) zooplanktonA situation superfically similar to Mysis in the Class 3 lakes in the lake trout growth example but Bythotrophes is immune to fish predation 2 - 3 cm Bythotrephes

19 The prediction: biomanipulationFact: Bythotrephes prefers Daphnia over Diaptomus. Hence, the model predicted that increased Bythotrephes abundance could cause Lake Michigan’s plankton community to return to a state similar to that of the 1970s: Diaptomus dominated zooplankton and a substantial community of filamentous blue-green algae – with no change in P

20 But events continued to overtake Lake Michigan (and all the Great Lakes)Hemimysis anomala Number 183 on a list of invasives that have made their way into the Great Lakes (usually in ballast water) The concern is its ability to out compete native invertebrate species for food thus further impacting fish food webs. The latest invader: Discovered November 2006

21 Significant species of concern (economically/ecologically)Zebra mussels Round goby Sea lamprey Eurasian ruffe purple loosestrife Eurasian watermilfoil, Bythotrephes Cercopagis Hemimysis Ciruna, K.A. et al The ecological and socio-economic impacts of invasive alien species in inland water ecosystems. Report to the Conservation on Biological Diversity on behalf of the Global Invasive Species Programme

22 Known species of future concernbighead carp (Hypophthalmichthys nobilis) silver carp (H. molotrix) black carp (Mylopharyngodon piceus) These species – all currently in the Mississippi drainage – fit the profile of successful Great Lakes invaders because of their high mobility, high reproductive capacity and voracious consumptive habits. Curious as to where they came from? They escaped from southern U.S. fish farms in the 1990s during flooding on the Mississippi River On Nov. 20, 2009, Professor David Lodge (Notre Dame) reported that 32 samples of water from Lake Michigan contained carp DNA

23 Asian carp and the Chicago ship channelRound goby made it from Lake Michigan into the Mississippi across the barrier – so it may also have failed to stop carp, although no fish have been reported to date.

24 Ironically on the same day carp DNA was reported in Lake Michigan, the US Supreme Court ruled that it would not force Illinois to close the ship canal Subsequently, Michigan is suing Illinois to force closure of the waterway. Ontario, Minnesota, Ohio, Wisconsin and Indiana have joined the lawsuit A decision is also pending from the federal government wrt closing the O'Brien Lock on the canal, effectively closing off access to the lake

25 Why are the Great Lakes (and Ontario Lakes in general) so susceptible to invasives?Several invasives in the GLB have also invaded European lakes without the same devastating impacts we see here WHY? Lakes that were subject to the last glaciation are hypothesized to be depauperate – only a reduced species complex was able to return from their glacial refugia, before isostatic rebound cut off the migration routes Invasives may thus be exploiting empty niches

26 Meanwhile back at Scavia et al.: Despite the model’s simplicity...Scavia et al., is considered a benchmark and a classic example of ecosystem based modeling. Unfortunately, constantly changing environmental conditions in the Great Lakes render it an incomplete snapshot. see the Meisenheimer article off the web page!

27 Case Study 2: Lake SimcoeAo = 722 km2 Aw:Ao = 5 SD = 2.3 Z = 14.2 m HRT = 10 y [P] = 15 ug.L-1 (range = ug.L-1) Holland River Lake Simcoe is the 5th largest “inland” lake in Ontario angler visits annually highest angling effort of any inland lake in Ontario winter angling effort 3x of that in the summer 2000–4000 fishing huts operate from January to March each year most sought after species in the winter fishery are lake whitefish, lake trout, and yellow perch Approximately $112 million dollars is generated annually by the fishery Evans et al CJFAS. 53:

28 Lake Simcoe P loading (historic loadings estimated from 210Pb-dated sediment cores)conversion from forested land to agriculture shift from row crops to pasture shift from pasture to corn/soybeans urbanization/cottages (2 000 to ) Today we are over an annual P-load of ~100 T conversion of swamps to intensive agriculture (the beginnings of Holland Marsh agriculture)

29 Estimate of the effect of swamp conversionsFrom pre-settlement P loading of mg P.cm–2.y–1 to 90.9 mg P.cm–2.y–1 The Holland River is the largest single contributor of P to Lake Simcoe – [P] average 100 ug.L-1 – (although loadings from agriculture are augmented by the sewage treatment plants at Bradford and Schomberg)

30 Recent changes to winter soil management has resulted in an additional P from these flooded soilsWith a shut-down of the pumps in the fall, groundwater floods the soils which quickly become anaerobic Fe3 (the oxidized form of iron) which binds orthophosphate (PO4) is reduced to Fe2 which does not bind PO4 When the pumps start running again, extremely high levels of P are pumped into the Holland River and then into Lake Simcoe

31 P appears to be the limiting nutrientWe do not have good N data, but the reasonably good relationship between P and Chl-A suggests P limitation Nicholls et al. (1985) had earlier reported a strong correlation between P concentration and phytoplankton biomass at various Lake Simcoe sampling stations also supporting strong coupling between P and phytoplankton production What then are our expectations for hypolimnetic oxygen? LSEMS Water quality update. Technical Report Imp. B.20

32 Optimal habitat volumeEvans et al. (1996) report that volume-weighted temperature-corrected hypolimnetic dissolved declined from approximately 4.5 mg.L-1 in 1975 to 2.0 mg.L-1 by 1993 In some pockets, the sediment water interface goes anaerobic, leading to internal P-loading (via the same Fe+3/Fe+2 mechanism we saw in the Holland Marsh soils) Optimal habitat volume 8–12°C (LT) 10–14°C (WF/C) > 7 mg.L–1 DO During late summer mean volume-weighted DO in the hypolimnion falls to < 3.0 mg.L–1 (the lethal range for salmonids) Lake Simcoe Basin Wide Report March 20, 2008

33 The Lake Simcoe Environmental Management Strategy (LSEMS) was created to “improve and protect the Lake Simcoe ecosystem by restoring water quality and fish habitat to support self-reproducing populations of whitefish, herring and lake trout.” LSEMS primary objective is to reduce P-loading by about 25% to an annual load of 75 t.y-1. LSEMS believes this reduction will increase end-of-summer deepwater dissolved oxygen concentrations from “present levels of about 3 mg L-1 to 5 mg L-1. While Nicholls (2001)* has reported some improvements in Lake Simcoe water quality (about 6 t.y–1 of P attributed to diversion of Aurora and Newmarket sewage effluent to the York–Durham trunk line), oxygen depletion rates are still high and he concludes that meeting the interim objectives for end-of summer dissolved oxygen under the LSEMS is “unlikely”: the improvements in P-loading from Newmarket/Aurora diversion were not accompanied by any measurable improvement in hypolimnetic oxygen concentrations continued human population growth and the associated increased loading from expanded sewage treatment facilities and increased urban stormwater runoff are nullifying the gains of any phosphate reductions internal loading of P and aeolian deposition are significant and difficult to control the target of 5 mg L-1 dissolved hypolimnetic oxygen remains sub-optimal spawning habitat has been degraded (sedimentation and zebra mussels) Bythotrephes appears to have altered prey availability for juvenile fish other invasives (smelt and goby) appear to be superior competitors to native corigonids *Nicholls, K.H Lake Simcoe water quality update: LSEMS phase II progress report, LSEMS Implementation Technical Report No. Imp.B pp.

34 Is freshwater a commodity or natural capital?Case Study 3: The GRAND (Great Replenishment & Northern Development) canal Is freshwater a commodity or natural capital?

35 The original GRAND Canal scheme was first conceived in the 1950's by Thomas Kierans.It involved construction of a huge dike across the northern end of James Bay. The rivers feeding into the bay would then create a giant freshwater reservoir (the size of Lake Ontario) which could be channeled back into the Great Lakes and transferred to the US via the Chicago ship canal.

36 For the original schemeThe total estimated cost in 1985 was $ billion. Deemed not cost-effective under any reasonable economic model it eventually faded from public view

37 In 2000, “La GRAND” re-emerged as the “James Bay Water Transfer Project”

38 The current version: Hudson Bay James Bay

39

40

41 415 km (open channel) 1 km wide, 15 m deep 125 km tunnel

42 James Bay Lake Superior

43 There are a number of significant environmental impacts:Wetlands at the south end of James Bay (Ramsar sites) Aboriginal communities on the James Bay coast Loss of the James Bay fishery Phosphorus loadings/transfers of exotics into Lake Superior Reductions in freshwater inputs to James/Hudson Bay and implications for thermohaline circulation

44 Global Energy and Water Cycle Experiment (GEWEX)The Mackenzie River + Hudson/James Bay plays an important part in regulating thermohaline circulation in the world’s oceans.

45

46 BUT… on another environmental front, how much energy does it take to pump water 180m uphill to Lake Superior? Minimum: 5 GW James Bay – sea level

47 How much is 5 GW? Pickering NGS Nanticoke GS coal-firedCurrent total generating capacity in Ontario is about 30,000 MW or 30 GW (only 85% of need) Niagara Falls generates ~4.6 GW (2.58 GW US, 2.05 Canada now, 1.6 more with the third Beck tunnel now under construction at $600 M) for 6.3GW Nanticoke GS coal-fired Otto Holden HGS

48 To pump water from James Bay to Lake Superior would require the equivalent of another Niagara Falls!Robert Moses (NY) Sir Adam Beck Complex DeCew Falls

49 Take-home message? We can probably engineer a transfer of water from James Bay. (Although one has to ask why we would use 5 GW of power to pump water to the Americans?) However the price (environmentally and economically) would be horrendous This project is unlikely to go forward in the near future What about 2025 or so as the Americans become increasingly water scarce? Severe environmental consequences have not prevented Alberta from rapid development of the oil sands Conservation (and learning to live within the limits of the ecosystem) would be better!

50 Once the world’s 4th largest freshwater lakeCase 4: The Aral Sea Once the world’s 4th largest freshwater lake (sponsored by Science Affairs Division of NATO)

51 The Aral Sea

52

53 What happened? The former Soviet Union's need for hard currency spurred the creation of a Central Asian cotton belt -- and an extensive irrigation system to support it. Today 90% of the water meant to reach the Aral Sea never gets there.

54

55 Check out the YouTube videoQuiet Chernobyl: The Aral Sea (www.youtube.com/watch?v=eVCf9lwW6eI)

56 Effects: Reductions in water recharge have caused a tripling in salinity, loss of most of the fishery and dramatic declines in biodiversity. The sea moderated the area's climate, and its shrinking has led to hotter, shorter summers and longer, colder winters. Infant mortality and birth defects have increased (perhaps due to airborne contaminated sediments).

57 In the face of widespread environmental consequences, including fisheries loss, water and soil contamination, and dangerous levels of polluted airborne sediments, Uzbekistan, Kazakhstan, and other Central Asian states continue to use this water to grow cotton and other export crops. It is generally agreed that the current situation is unsustainable, but the poverty and export dependency of the Central Asian states have prevented any real action, and the sea continues to shrink – despite an $85 million rehabilitation project, funded by the World Bank, to improve irrigation efficiency and other water infrastructure. A $300 million project is due to begin in this year Lake Chad, once the world’s 6th largest lake, also continues to shrink as do hundreds of smaller lakes in regions as geographically distinct as Siberia, Alaska and the African continent

58 85$ M and 3 years later? 2005 "We are doing what is possible for the small sea (in the north). But the southern Aral is beyond saving," says Joop Stoutjesdik, the World Bank's head of irrigation programs. 2008

59 Check out the recent issue of The Economist for a 5th case studyOn the web site under Dead Sea Water levels are dropping by ~ 1 m.y-1 as consumptive withdrawals (Israel, Palestine and Jordon) have reduced inflows to 5% of renewable flow rates The “solution” is a 200 km conduit from the Red Sea, desalination with the energy from the downhill 6 B $ Will the less dense Red Sea water really mix into the Dead Sea? Will the algal blooms that characterize the Red Sea change the ecological characteristics of the Dead Sea? Will the energy required to pump water up in two places outweigh the energy gained in the downhill run? And ever yet again the Friends of the Earth - Middle East asks: why doesn’t anybody consider better water husbandry?

60 Or the 12 water issues of the next 2 decades from the World Economic Forum meetings in FebruaryThe executive summary under Water Issues Overview The complete report under Water Issues Water scarcity will increase dramatically, with significant socioeconomic repercussions Tensions over water will increase as scarcity increases Global grain harvests will be in jeopardy More countries will rely on food imports and the livelihoods of many people will be threatened. And a host of other cheerful predictions – useful if you have to write an essay!

61 Take-home message? Use your knowledge to make a difference!

62 Let’s keep them Great!