1. Past experiences and future research on
diapause in Uruguay
Carlos Iglesias, Néstor Mazzeo, Nicolás Vidal, Miriam
Gerhard, Matías Arim, Mariana Meerhoff & Erik Jeppesen
caif968@hotmail.com
Special session: Diapause as invertebrate survival strategy in instable aquatic environments

2. SUMMARY:
Brief history
Our working questions
Where we are
Some results
Future research
Doubts!

3. Brief history
1984
creation of Limnology section at Facultad de Ciencias
 Research focus on aquatic communities principally in lakes
1998
Research Group in Ecology and Restoration of Aquatic Systems

Eutrophication and Restoration of Shallow Lakes

Ecosystemic approach

Paleolimnology
International cooperation
(Moss, Jeppesen, Reynolds, Scheffer)

2006
Split of the Research group (2 permanent posisitions)
SNI
2008
Move to CURE Maldonado (9 DT permanent positions)

4. Our working questions
Do fish structure the zooplankton
community in subtropical shallow
lakes? (effects of eutrophication)
Do macrophytes (PVI & architecture)
influence fish- zooplankton
interactions?
Resting egg banks are capable to
develop different zooplankton
From Hugie & Dill 1994
community structure if
biomanipulation techniches are
applied?

5. Where are we
Different approaches
• Empirical
• Experimental
• Modeling
• Comparative studies
• Gradient analyses

6. Where are we
Lacerot, 2010
• Lower richness
• 5.5x lower density
subtropical lakes
in
• Large-bodied zooplankters
infrequent or absent.
Meerhoff et al 2007 FWB
Warm -
Cold +
Gillooly & Dodson, 2000 L&O 45: 22-30

7. Where are we
PREDATION
By fish &/or invertebrates
WHY ARE THEY
SMALLER?
PHYSIOLOGICAL
Growth, reprod, respiration
rates
Moore et al 1996
Jeppesen et al 2007, Meerhoff 2008
Lacerot 2010
Fish size
Temperature
Zoop size
Food quality
FOOD QUALITY
FOOD QUANTITY
Cyanobacteria and inedible
algae
Elser et al 2000 De Mott et 2001
Food threshold higher for
large species in warmer lakes
Duncan, 1989

8. Some results
 Experiments on the structuring role
of fish and cascading effects over other
communities in simple and more
strucutrated environments
 Combined approaches
 Field surveys for seasonal
dynamics on water and sediment
records in a large set of lakes

9. Some results
LAKE BLANCA
MESOCOSM APPROACH
SP
EP
OW
Iglesias et al FWB 2008

10. Some results
Extensive fish kill in Lake Rivera
Determined the appearence of Daphnia
and bigger than expected
20000
15000
LAKE RIVERA kill
Extense fish
Brachionus rubens
Metacyclops mendocinus
Daphnia obtusa
10000
Brachionus urceolaris
Metacyclops mendocinus
Moina micrura
Daphnia obtusa
BIOMASS
(µg/L)
5000
Metacyclops mendocinus
Daphnia obtusa
4000
3000
2000
Brachionus urceolaris
Metacyclops mendocinus
Moina micrura
1000
0
SUMMER
Igleisias et al., 2011 Hydrobiologia 667:133-147
AUTUMN
WINTER
ROTIFERS
COPEPODS
OTHER CLADOCERANS
Daphnia obtusa
4000
LAKE RODO
3500
Keratella tropica
Keratella cochlearis
Keratella tropica
Brachionus calyciflorus
Metacyclops mendocinus
Notodiaptomus incompositus
SPRING

11. Some results
FISH EXCLUSION EXPERIMENT
Large sized cladocerans appeared after fish exclusion
When fish was added then they disappeared or their
size was diminished
Igleisias et al., 2011 Hydrobiologia 667:133-147

12. Some results
50% of the lakes (9) Epphipia
was found.
In 3 of them Daphnia also found
in water samples
In 3 of them only in water
Overall Daphnia potentially in 75%
Igleisias et al., 2011 Hydrobiologia 667:133-147

13. Some results
TEMPORARY PONDS
50 Temporary systems
Dryed during summer
Laguna de Castillos basin

14. Some results
TEMPORARY PONDS
Five days sediment incubation with
water from the ponds in 1L cubitainers
continously aireated
Comparison with active comunity
from the ponds (50 µm)
(3 replicates x 10 ponds) + 30 controls (1xpond)

15. Some results
TEMPORARY PONDS
Charcos de Hidroperíoodo de Hidroperíoodo Largo
Charcos Corto
Ostrácoda
*
*
Charcos de Hidroperíoodo Largo
*
*
Nauplios
* *
Calanoides
*
*
*
*
*
Sediment incubation
Cyclopoides
Clad pelágico
* *
Worked!!!
*
*
Clad fitófilos
Rotífera
50 40
0
o Corto
20
700 650 600 550 500 450 400 350 300 250 200 150 60 120 400 140 20
0
0
20
40
140
120
60
100
80
80
100 100 50
Ostrácoda
*
0
0
Charcos de Hidroperíoodo Largo
Charcos de Hidroperíoodo Corto
20
*
*
40
60
80
100
120
140
Charcos de Hidroperíoodo Largo
*
Nauplios
*
*
Calanoides
*
*
Active community
Cyclopoides
Clad pelágico
* *
Clad fitófilos
Rotífera
200
100
*
*
0
100
200
300
400
500
600
700 650 600 550 500 450 400 350 300 250 200 150 60 50 400
140
120
100
80
100
700 20
0
0
20
40
High correlation among Active and
latent communities
60
80
100
120
140

16. Future research
Empirical-experimenta approach
EXPERiMENTAL
Lab microcosm
Mesocosms
“Whole lake”
Empirical evidence
Plants
Fish
Zooplankton

17. Future research
 Study
the “potential” zooplankton
community vs anual varitation in the
water colum
Miriam Gerhard MSc Thesis
Also invetigate correlation between
Active and latent zooplankton
Investigate composition & abundance
Calculate saturation & rarefaction

18. Future research
 Laguna
Blanca as “our case of study”, piscivorous fish recolonized the
system. Daphnia registered in water samples vs. previous data

19. Future research
 Latitudinal analyses of ephippia occurence and sediment incubation
in samples from 88 lakes from SA 5 to 55 lat

20. Future research
Future research
 Emergence
and ephippia
production phenology

21. Future research
Future research
 Emergence
and ephippia
production phenology
Plastic Tissue Culture Flask
Friction fit: mouth of flask fits snuggly over tubing
Tubing attached to funnel Tygon Tubing
and funnel to bottle
Small plastic funnel
with “hot glue”
Plastic bottle from water cooler
(with bottom cut off)
Mesh windows attached with hot glue
Sheet-metal collar, with hole for bottle: rests on sediment surface
Metal tubing legs (we made them with electrical conduit)
They project about 20 cm into sediment to hold trap in place
Photo by CM Kearns
Draw by Nelson G. Hairston

22. Doubts!
 How to induce eclosion in lake samples
 To dry or not to dry
 Cool or not, how long
 Culture meddium vs lake water
 Emergence Traps frequency of sampling, how many of them, where
 Ephippia production traps…………..
SS4-0187-Iglesias Limnologia2012

23. Thanks!!
Gracias!!
Obrigado!!
Thanks for finantial support to AU, NERI and the Ministry of Science, Technology and Innovation in
DK. PDT, ANII, CSIC –Udelar in Uruguay

25. Zooplancton
Rotíferos
Copépodos
Cladóceros
Importantes
consumidores
primarios en los sistemas lénticos
Filtradores de gran tamaño
Sucesión estacional
Huevos de resistencia: Efipios
Escape temporal y espacial
Mecanismos de respuesta a
condiciones adversas
Comunidad activa
Comunidad potencial

26. Brief history
1998-2012
ca. 30 thesis