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Crustaceana 86 (4) 507-513
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CRUSTACEAN ZOOPLANKTON COMMUNITIES IN LAKE GENERAL
CARRERA (46°S) AND THEIR POSSIBLE ASSOCIATION WITH
OPTICAL PROPERTIES
BY
PATRICIO DE LOS RÍOS-ESCALANTE1,2,5 ), ESTEBAN QUINÁN1 ) and
PATRICIO ACEVEDO3,4 )
1 ) Laboratorio de Ecología Aplicada y Biodiversidad, Escuela de Ciencias Ambientales, Facultad
de Recursos Naturales, Universidad Católica de Temuco, Casilla 15-D, Temuco, Chile
2 ) Núcleo de Estudios Ambientales, Universidad Católica de Temuco, Casilla 15-D, Temuco, Chile
3 ) Departamento de Ciencias Físicas, Facultad de Ingeniería, Ciencias y Administración,
Universidad de la Frontera, Casilla 54-D, Temuco, Chile
4 ) Center for Optics and Photonics, Universidad de Concepción, Casilla 160-C, Concepción, Chile
In central and south Chilean Patagonia (46-51°S) there are numerous deep,
oligotrophic lakes of glacial origin and/or with glaciers associated with their basins
(Soto & Zúñiga, 1991; Soto et al., 1994; De los Ríos-Escalante, 2011), which
contain zooplankton communities with a low number of species and high calanoid
dominance (Soto & Zúñiga, 1991; De los Ríos & Soto, 2006, 2007; De los RíosEscalante, 2010). This region is practically unpolluted and has been little studied
due mainly to geographical difficulties — mountains, ice fields and fiords — and
the weather, characterized by strong winds, especially in the southern spring and
summer (October-February) (Soto et al., 1994; De los Ríos-Escalante, 2010).
In Central Patagonia (46-49°S) there are three large, deep lakes with marked
glacial influence, which straddle the border between Chile and Argentina, namely
General Carrera/Buenos Aires; Cochrane/Pueyrredón; and O’Higgins/San Martín
(Niemeyer & Cereceda, 1984; Soto & Zúñiga, 1991). From a geomorphological
point of view, these lakes are characterized by numerous closed bays, some of
which receive effluent rivers carrying glacial sediments. The depth of the lakes
varies up to a maximum of 400 m (Soto & Zúñiga, 1991). Unfortunately there
are no detailed limnological studies of these great lakes, with the exception of
restricted reports of their trophic status (Soto & Zúñiga, 1991), zooplankton
species (Menu-Marque et al., 2000; De los Ríos & Soto, 2007; De los RíosEscalante, 2010), and detailed studies on benthic fauna in the surrounding basin
5 ) Corresponding author; e-mail: [email protected]
© Koninklijke Brill NV, Leiden, 2013
DOI:10.1163/15685403-00003182
508
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Fig. 1. LANDSAT/ETM+ images (B2) Visible-Green, five zones (S1-S5) denoted with different
water reflectance.
(Moya et al., 2009; Valdovinos et al., 2010). Nevertheless, on the basis of
published information for Argentinean lakes in similar latitudes, these lakes
would be oligotrophic, with phytoplankton assemblages dominated by diatoms,
zooplankton with low species number and calanoid dominance, few native species
and presence of salmonids (Modenutti et al., 1998). The aim of the present study
is to make a preliminary analysis of the zooplankton communities in different bays
of Lake General Carrera and produce a preliminary characterization of community
structure.
Lake General Carrera is located in the Aysen Region (fig. 1) and forms part of
the Baker River basin. It covers 1892 km2 , reaches a maximum depth of 410 m
(Moya et al., 2009; Valdovinos et al., 2010), and contains numerous bays. The
study samples were collected in October 2002 in the following bays of the lake:
Avilés River, Murta Bay, Jara Bay, Chile Chico, Fachinal, Ibáñez River, Guadal
Bay and Tranquila Bay (table I and fig. 1).
Sampling collection and data analysis: the samples were collected with vertical
hauls at varying depths between 10 and 30 m, using a plankton net of 20 cm diameter and 100 μm mesh size. The specimens collected were fixed with 10% formalin
and identified according to specialized literature (Araya & Zúñiga, 1985; Bayly,
1992). The data were transformed to indicate relative abundance (%), and analysed
using a Jaccard Cluster Analysis with single-link similarity to determine potential
similarities between sites. Biodiversity Pro Software, Version 2.0 (McAleece et al.,
2007) was used for this analysis.
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TABLE I
Geographical location, percentage abundance and optical properties (reflectance) of crustacean
species observed in different bays of Lake General Carrera, Chile
Murta
bay
Jara
bay
Chile
Chico
Fachinal
bay
Ibáñez
river
Guadal
bay
Tranquila
bay
Latitude (S)
46°29 30 46°29 16 46°31 28 46°30 40 46°17 58 46°49 59 46°37 43
Longitude (W) 72°41 49 72°48 59 72°41 43 72°57 34 72°55 59 72°41 54 72°39 44
Abundance
Neobosmina
0.0
0.0
1.9
0.8
0.0
0.1
0.0
chilensis
(Daday)
Boeckella
100.0
100.0
98.1
99.2
100.0
99.9
100.0
michaelseni
(Mrázek)
Reflectance
B1
B2
B3
B4
B5
B7
0.0493
0.0343
0.0036
0.0057
0.0016
0.0005
0.0180
0.0260
0.0038
0.0035
0.0013
0.0002
0.0186
0.0030
0.0036
0.0051
0.0014
0.0003
0.0260
0.0047
0.0038
0.0049
0.0018
0.0005
0.0271
0.0224
0.0009
0.0072
0.0013
0.0002
0.0757
0.0352
0.0008
0.0089
0.0016
0.0003
0.0661
0.0308
0.0019
0.0054
0.0017
0.0006
The second step used a LANDSAT/ETM+ image obtained on 14 October
2001 (fig. 1), provided by the Land Processes Distributed Active Archive Center
(LP DAAC), U.S. Geological Survey (http://LPDAAC.usgs.gov). The bands of
visible, near and mid-infrared were calibrated radiometrically to spectral radiance
and then to reflectance, with atmospheric correction being applied (table II).
A correlation index was applied between the relative abundance of Boeckella
michaelseni (Mrázek, 1901) and the reflectance values (table III), and finally a
regression analysis was applied to the most significant regression. All statistical
analyses were done using the Xlstat 5.0 software.
TABLE II
Technical characteristics of ETM+ sensor of LANDSAT 7 Satellite
Band
B1
B2
B3
B4
B5
B7
Wide band (nm)
452-514
519-601
631-692
772-898
1547-1748
2065-2346
Range
Visible-blue
Visible-green
Visible-red
Near infrared
Mid-infrared
Mid-infrared
Spatial resolution (m)
30
30
30
30
30
30
510
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TABLE III
Correlation analysis of crustacean species observed in different bays of Lake General Carrera, Chile.
P values < 0.05 denote significant differences
Correlation coefficient
P
B1
B2
B3
B4
B5
B7
0.386
0.197
0.563
0.094
−0.467
0.146
0.278
0.273
−0.517
0.118
−0.287
0.266
The results revealed a low species number (one or two). The dominant or exclusive species in some sites was the calanoid B. michaelseni, which coexisted
with the small cladoceran Neobosmina chilensis (Daday, 1902) only in the Chile
Chico and Fachinal Bay sites (table I). If we compare these results with the optical
properties at the sites, a weak direct association is observed between B2 (corresponding to green reflectance in the visible spectrum) and the relative abundance
of B. michaelseni (table II) with confidence level 0.1 (table I). Regression analysis
revealed a significant linear association between B2 and the relative abundance of
B. michaelseni (fig. 2). The results of the cluster analysis revealed the existence
of one main group, consisting of Tranquila Bay, Guadal Bay, Ibáñez River, Jara
Bay and Murta Bay where only B. michaelseni is present, while the most different
comparable sites are Chile Chico and Fachinal bay (fig. 3).
Fig. 2. Lineal regression between B2 LANDSAT/ETM+ reflectance and relative abundance of
Boeckella michaelseni (Mrázek, 1901).
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511
Fig. 3. Dendrogram with the zooplankton relative abundance data of sites studied.
The results described above agree with results obtained for other lakes of
glacial origin, for example, lakes Sarmiento and Del Toro in the Torres del Paine
National Park (Campos et al., 1994a, b), where the markedly abundant calanoid
species B. gracilipes Daday, 1901 and/or B. michaelseni are associated with low
abundances of cyclopoid copepods and the cladoceran N. chilensis. Similar results
were observed for other glacial, oligotrophic lakes in Torres del Paine National
Park, such as Nordsdenkjold and Grey, where the zooplankton communities consist
of only two species (B. michaelseni and Tropocyclops prasinus (Fischer, 1860))
(Soto et al., 1994; Soto & De los Ríos, 2006; De los Ríos-Escalante, 2010; De los
Ríos-Escalante et al., 2011). This situation differs from that of another Patagonian
lake with glacial influence, Todos los Santos Lake, which has four species (De los
Ríos & Soto, 2007).
Zooplankton communities can be affected by glacial influence. In marine environments zooplankton mortality, mainly associated with the chemical properties
of the ice, has been found in areas close to ice fields (Weslawski & Legezynska,
1998). For Patagonian lakes the glacial influence is water turbidity due to glacier
sediments and dissolved organic matter which prevent light penetration into water column (Modenutti et al., 2000; Pasquini & Depetris, 2011). In Lake General
Carrera/Buenos Aires (Hein et al., 2010), it is probable that the marked glacial
512
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influence in the form of sediments may affect phytoplankton activity. As a result the lake does not support enough phytoplankton biomass to sustain abundant
zooplankton biomass. This would make it similar to some lakes with glacial influence in Torres del Paine National Park where only two species are found (Soto
et al., 1994; De los Ríos-Escalante, 2010). Considering that Lake General Carrera
(Chilean zone) contains bays with glacial influence where green coloring is observed (e.g. Puerto Ibáñez), this would explain the absolute abundance of calanoid
B. michaelseni in bays with high reflectance of green light, because these zones
would be oligotrophic due to low light penetration. Although the correlation in
this study was weak (table III), a stronger correlation would probably be found if
a more intensive study were carried out. The results presented indicate that a potential correlation between zooplankton assemblages and optical properties might
possibly be found; however it would be necessary to carry out more intensive studies and obtain more data to be able to confirm or discount the possibility of finding
potential correlations.
ACKNOWLEDGEMENTS
The present study received funding from CEFOP CONICYT FB0824 and DI080040 of the Research Directorate of Universidad de la Frontera; Project DIDUACH d2001-11 of Universidad Austral de Chile; and the Research Directorate
of Universidad Católica de Temuco (Project MECESUP Project UCT 0804).
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First received 10 May 2012.
Final version accepted 1 December 2012.
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