TESTING A MODEL OF ZOOPLANKTON SECONDARY
PRODUCTION IN CULTURES OF Daphnia magna
M. Gómez* , I. Ma ínez* , I. Mayo*, J.M. Mo ales*& T.T. Packa d*
* Labo a o io de Oceanog a ía Biológica, Facul ad de Ciencias del Ma , Uni e sidad de Las Palmas de G an Cana ia, Campus Uni e si a io de Ta i a 35017, Las Palmas
de G an Cana ia, Islas Cana ias, España
Con ac o: [email protected]
Ha es Size
measu emen
F eeze
-20ºC
Pa ame e s
measu emen s
D y mass (Lo eg o e,1966)
G ow h a e
Condi ion ac o
CF = (a · W)/L3
Mo he
cul u e
(20L)
Phy oplank on
cul u e
(Scenedesmus sp.
+Ankis odesmus
sp.)
Co n lou
cul u e
(come cial)
Yeas cul u e
(come cial)
Di e en cul u es o D. magna we e g own on phy oplank on, bake ’s yeas ,
o co n lou a 18-21°C. G ow h a es we e calcula ed om ime cou ses o size
(Fig.1) and d y mass (Fig. 2 ).
MATERIAL AND METHODS
RESULTS
Table 1. Cha ac e is ics o he di e en D. magna cul u es
Kind o ood
Maximum
size
Lmax(mm)
Age
o
Lmax
(days)
Maximum
weigh
Wmax(µg)
Age
o
Wmax
(días)
Go w h
a e
(d-1)
Condi ion
ac o
(CF)
Tempe a u e
(ºC)
Phy oplank on
mix u e
1.42 ± 0.19
18
153
13
0.203±0.03
( 2=0.77)
5.78
20.9 ± 1.1
Yeas
2.01 ± 0.14
17
110
12
0.317±0.03
( 2=0.94)
1.19
20.1 ± 0.5
Co n Flou
1.38 ± 0.07
19
150
19
0.136±0.01
( 2=0.72)
4.51
19.2 ± 1.2
Table 2. Reg ession analysis o size and d y-mass.
W=d y-mass, in µg; L=size, in mm (*) p<0.0001
Kind o ood
Equa ion
2
Phy oplank on
mix u e
Ln W = 1.39 Ln L + 4.51
0.92 (*)
Yeas
Ln W = 2.68 Ln L + 2.67
0.98 (*)
Co n lou
Ln W = 1.02 Ln L + 4.46
0.93 (*)
CONCLUSIONS
 Al hough he highes global g ow h a es we e ob ained wi h yeas (0.317d-1),
he highes alues o he condi ion ac o (5.778) and seconda y p oduc ion
(508 µg d y mass·d-1) as well as he maximum weigh we e ound in daphnia
ed on phy oplank on. This mix u e seems o be he op imal ood o cul u ing
Daphnia.
 The Hun ley and López (1992) model o e es ima es he seconda y p oduc ion
by 174%.
 On a u ili a ian basis, because size is such a good index o biomass, i p o ides
a simple and mo e eliable measu e o g ow h- a e han d y-mass.
BIBLIOGRAPHY:
Hun ley, M.E. & M.D.G López, 1992. Tempe a u e-dependenden p oduc ion o ma ine
copepods: a global syn hesis. Ame ican Na u alis , 140:201-242
Vij e be g, J., 1989. Cul u e echniques o s udies on he g ow h de elopmen and
ep oduc ion o copepods and cladoce ans unde labo a o y and in si u
condi ions: a e iew. F eshwa e Biology 21:317-373
Fig. 2 and Fig. 3 .- D. magna g ow h illus a ed by he d y-mass ime-cou se and daily
g ow h a e, espec i ely. A: Fed on phy oplank on mix u e; B: Fed on yeas ; C: Fed
on co n lou . Dashed lines ep esen he 95% con idence in e als.
INTRODUCTION
Seconda y p oduc ion is he p oduc o biomass and g ow h a e. The key o
i s es ima ion is a good measu emen o g ow h a e. P incipal ac o s con olling
his a e in zooplank on a e he amoun , and he quali y o ood (Vij e be g, 1989).
He e, we measu e he daily and o e all g ow h a e in he Cladoce an, Daphnia
magna, aised unde di e en ood egimes. We hen used he measu emen s as a
e e ence s anda d o model zooplank on seconda y p oduc ion in na u al
popula ions.
Fig.1 .- D. magna g ow h illus a ed by he size ime-cou se. A: Fed on phy oplank on
mix u e; B: Fed on yeas ; C: Fed on co n lou .
Fig.1
Fig.2 Fig.3
Seconda y p oduc ion alues (pe iod o 12 days)
Phy oplank on cul u e
(µg d y mass·d-1)
Yeas cul u e
(µg d y mass·d-1)
Co n lou cul u e
(µg d y mass·d-1)
508.88
307.46
328.26
Using he exp ession P = B 0.0455 e0.111T (Hun ley and López, 1992)
Phy oplank on cul u e
(µg d y mass·d-1)
Yeas cul u e
(µg d y mass·d-1)
Co n lou cul u e
(µg d y mass·d-1)
1379.32
776.75
943.16
(B = biomass, T = empe a u e)
In compa ison, ou measu emen s a e app oxima ely 60% lowe han he Hun ley-
López model p edic . I s seems ha hei equa ion may o e es ima e he seconda y
p oduc ion in ou cul u e sys em.
Yeas
Co n lou
Mix u e o Scenedesmus sp.
Ankis odesmus sp.
mix u e
Daphnia magna