Irina Izaguirre

Universidad de Buenos Aires | UBA · Department of Ecology, Genetics and Evolution

Although agricultural intensification has been linked with the increment of lake eutrophication and shallow lake research has demonstrated the importance of submerged macrophytes for maintaining water clarity, less is known about the role of macrophytes and the effects of agriculture on shallow lakes of the global south. Shallow lakes in the Pampea...

Cyanobacterial blooms imperil the use of freshwater around the globe and present challenges for water management. Studies have suggested that blooms are trigged by high temperatures and nutrient concentrations. While the roles of nitrogen and phosphorus have long been debated, cyanobacterial dominance in phytoplankton has widely been associated wit...

Over the past decades, shallow lakes of the Pampean Plain, Argentina, have been shifting from clear vegetated to turbid phytoplanktonic states due to anthropic pressures. It is not clear, though, if this change in state also involves a change in the overall CO2 and CH4 balance of these lakes. Therefore, the main objective of this work was to assess...

Biogeographical patterns provide insight into the evolutionary and ecological processes that shape biodiversity. Patterns of microbial biogeography have remained poorly described because adequate tools for measuring microbial diversity (such as molecular techniques and technologies) have emerged only recently. One aspect that has received a great a...

The biogeography of bacterial communities is a key topic in Microbial Ecology. Regarding continental water, most studies are carried out in the northern hemisphere, leaving a gap on microorganism’s diversity patterns on a global scale. South America harbours approximately one third of the world’s total freshwater resources, and is one of these unde...

Rainbow trout (Oncorhynchus mykiss) was introduced in most lakes of Patagonia, generating concern about its impact on the receiving communities. However, the information about the effects of trout in stocked lakes of this region is still fragmentary. We conducted a comprehensive comparative study of fishless and stocked lakes of the arid southern P...

Rainbow trout have been stocked in naturally fishless lakes in the reproductive area of the endangered Hooded Grebe, an endemic aquatic bird of Southern Patagonia. The effects of trout introduction were proposed as one of the potential causes of their critical situation. Trout could modify the trophic structure of the aquatic community by altering...

Phytoplankton size structure has profound consequences on food-web organization and energy transfer. Presently, picocyanobacteria (size < 2 µm) represent a major fraction of the autotrophic plankton of Pampean lakes. Glyphosate is known to stimulate the development of picocyanobacteria capable of degrading the herbicide. Due to the worldwide adopti...

In this study we explored how picoplankton community structure and diversity varied along three cascade oligo-mesotrophic reservoirs of the Limay River (Patagonia, Argentina): Alicura, Piedra del Águila and Ramos Mexía. We analyzed the spatial changes, covering lotic and lentic stretches along a gradient of 262 km from Andes to steppe, and we also...

The ecological status of Pampean shallow lakes is evidenced by Cyanobacteria Harmful Blooms impairing these nutrient enriched, turbid and polymictic water bodies spread along the Central Plains of Argentina. Under the premise that shallow lakes are sentinels of global climate and eutrophication, a 3-year research in ten lakes located across a clima...

Submerged macrophytes play a key role in maintaining clear vegetated states in shallow lakes with alternative regimes, but their role on methane dynamics has been less explored. They might enhance methane emissions by providing organic matter for methanogenesis but they could also supply oxygen to the sediments therefore increasing methanotrophy, a...

• Wetlands in arid regions are characterized by their great heterogeneity, often including endemic species that contribute to regional aquatic biodiversity. In the Patagonian steppe, most lakes are naturally fishless and sustain a rich aquatic biodiversity, including endemics; however, many of these lakes have been stocked with Oncorhynchus mykiss...

Previous studies conducted in summer in the lakes at Hope Bay (Antarctic Peninsula) between 1991 and 2007 showed a large numerical contribution of flagellated Chrysophyceae to the phytoplankton communities, particularly in the oligotrophic lakes, as evidenced by light microscopy observations and molecular fingerprinting. Given the ecological releva...

Carbon dioxide and methane emissions from inland waters constitute a significant component of the global carbon cycle. Among inland waters, shallow lakes are considered biogeochemical hotspots and are highly abundant in some landscapes. The Pampean Plain in Buenos Aires, Argentina, is a region that hosts thousands of shallow lakes under different a...

The Salado River basin, Buenos Aires, Argentina, contains numerous permanent shallow lakes under anthropic pressure due to different land uses/land covers (LULC) in their catchments. Here, we explored the relation of LULC in the surrounding areas and the physical and chemical variables of six shallow lakes of the aforementioned basin with phytoplan...

Antarctica holds a great number of inland lakes whose characteristics vary from ultra-oligotrophic to hypereutrophic, and from freshwater to hypersaline. The harsh conditions in these ecosystems (extremely low temperatures, large annual variation in solar radiation, light limitation below the ice) account for adaptive strategies of the selected phy...

Protists dominate eukaryotic diversity and play key functional roles in all ecosystems, particularly by catalyzing carbon and nutrient cycling. To date, however, a comparative analysis of their taxonomic and functional diversity that compares the major ecosystems on Earth (soil, freshwater and marine systems) is missing. Here, we present a comparis...

Bacterial communities play an important role in the biogeochemical cycle in reservoir ecosystems. However, the dynamic changes in both planktonic and sediment bacterial communities in a highly regulated dam reservoir remain unclear. This study investigated the temporal distribution patterns of bacterial communities in a transition section of the Th...

Vegetated wetlands are naturally subjected to changes in their water-level and macrophyte coverage leading to high habitat heterogeneity. The opportunistic ecological strategy of many planktic algae and bacteria makes them suitable for studying adaptive mechanisms to environmental change in wetlands at different temporal and spatial scales. In this...

Species diversity is one of the most informative community metrics and is influenced by regional and local factors. We studied the spatial patterns of taxonomic and functional phyto- and zooplankton diversity in 33 lakes from two basaltic plateaus of the arid Patagonia. The aims of our study were to evaluate α, β and γ taxonomic diversity of phyto-...

Massive use of glyphosate-based herbicides in agricultural activities has led to the appearance of this herbicide in freshwater systems, which represents a potential threat to these systems and their communities. These herbicides can affect autotrophic and heterotrophic picoplankton abundance. However, little is known about glyphosate impact on the...

Collaborative community-based approaches are proposed as a way to overcome the difficulties exerted by a broad range of social-ecological traps that emerge at the reconfiguration of social-ecological systems onto sustainable paths. Despite this, a deep examination of the social-ecological processes and interactions that constraint these approaches...

Knowledge of the anthropogenic drivers of environmental change is important for understanding ecosystem dynamics. We studied 2 of these factors — an invasive mollusk (golden mussel Limnoperna fortunei) and the herbicide glyphosate — focusing on the effects of the mussel, the herbicide, and their interaction on the abundance and composition of diffe...

Collaborative community-based approaches are proposed as a way to overcome the difficulties exerted by a broad range of social-ecological traps that emerge at the reconfiguration of social-ecological systems onto sustainable paths. Despite this, a deep examination of the social-ecological processes and interactions that constraint these approaches...

The Americas are one of the world’s major natural freshwater reserves, characterized by diverse climates and heterogeneous ecosystem types. Eutrophication and climate change trigger the growth of potentially toxic cyanobacteria. In this study, we investigate the distribution of planktonic cyanobacteria in lakes around the Americas with a gradient o...

In this study we analyzed the structure of the microbial planktonic communities in 16 lakes located in one of the Patagonian plateaus. In these environments picoplankton constitute a key component of the food webs. We compared lakes with different regimes (clear vegetated and turbid), in periods with contrasting hydrological conditions. Samplings w...

RESUMEN. Los lagos urbanos son ecosistemas que tienden a una rápida eutrofización y que pueden desarrollar floraciones fitoplanctónicas en el período estival. En tres lagos urbanos de la Ciudad Autónoma de Buenos Aires (Regatas, Rosedal y Centenario), sometidos a diferentes estrategias de manejo, durante el período cálido septiembre 2014-abril 2015...

Los lagos urbanos son ecosistemas que tienden a una rápida eutrofización y que pueden desarrollar floraciones fitoplanctónicas en el período estival. En tres lagos urbanos de la Ciudad Autónoma de Buenos Aires (Regatas, Rosedal y Centenario), sometidos a diferentes estrategias de manejo, durante el período cálido septiembre 2014 - abril 2015 se est...

Strobel Plateau hosts more than 1,500 shallow lakes displaying different water regimes, which constitute the habitat for many species. Although the region is naturally fishless, many of the lakes were stocked with trout, bearing uncertainty about the possible effects on the ecosystem. The main objective of this study was to analyze the characterist...

Due to an unfortunate turn of events, the first- and surnames of all authors were transposed in the original publication. The original article has been corrected and the proper representation of the authors’ names and their affiliation is also listed here.

The 18th workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), the first ‘‘tropical’’ IAP ever, the third one outside Europe, and the first one in South America, was held in Natal, Brazil, from August 27 to September 3, 2017, and its main ecological theme was the Phytoplankton and its biotic interactions. The taxon...

El presente informe tuvo como objetivo realizar un relevamiento de los recursos biológicos existentes en la Reserva Ecológica Ciudad Universitaria - Costanera Norte (RECU-CN) y diagnosticar la situación del área. El mismo se realizó mediante la recopilación de información existente producida en los últimos 37 años, la consulta a distintos actores...

In order to evaluate patterns of phytoplankton community structure and primary production limitation, we analyzed the phytoplankton communities (chlorophyll a, biovolume, species richness, and primary production) of a set of 20 shallow lakes encompassing a wide range of phosphorus and light levels. The degree of limitation or co-limitation by phosp...

Biodiversity loss in shallow lakes is associated to several factors among which water level decrease and fish introduction are indicated as potential stressors. The Patagonian basaltic plateaus, located in one of the most arid regions of South America, hold thousands of shallow lakes and ponds and some large lakes, where vegetated lakes are the pri...

La llanura pampeana es un gran humedal que abarca el centro-este de la República Argentina. Se ha descrito la presencia de tres tipos de lagunas en dicha región: claras vegetadas, turbias fitoplanctónicas y turbias inorgánicas. Hasta hace poco tiempo los cuerpos de agua pequeños y medianos no eran considerados en los balances globales de gases de e...

Los proyectos de rehabilitación ecológica en ambientes urbanos vienen incrementándose año a año, siendo uno de los principales desafíos a nivel de la gestión ambiental la implementación de una evaluación sistemática de los mismos. La utilización de indicadores microbianos para el monitoreo de acciones de manejo y rehabilitación no es frecuente, aun...

Los proyectos de rehabilitación ecológica en ambientes urbanos vienen incrementándose año a año, haciendo evidente la necesidad de una integración entre los componentes sociales y ecológicos para una mayor sustentabilidad de los proyectos, así como una evaluación sistemática de los abordajes llevados a la práctica. Se presentará una experiencia rea...

Participative ecosystem restoration approaches at the urban space usually collide with traditional top-down approaches where the design and execution of the work are done by the governance without local community participation. Here we present an experience (2015-2016) held in cooperation with workers of a social cooperative associated to a Nationa...

The patterns and mechanisms underlying the genetic structure of microbial populations remain unresolved. Herein we investigated the role played by two non-mutually exclusive models (i.e. isolation by distance and isolation by environment) in shaping the genetic structure of lacustrine populations of a microalga (a freshwater Bathycoccaceae) in the...

We characterized molecularly the first freshwater member ever reported for the family Bathycoccaceae in Lake Musters (Argentinean Patagonia). Members of this family are extremely numerous and play a key ecological role in marine systems as primary producers. We cloned a fragment comprising the SSU rRNA gene + ITS region from environmental DNA using...

Phytoplankton research in a number of shallow lakes in southern Patagonia revealed the occurrence of three noteworthy Cosmarium species. One of them, Cosmarium decussare Brook et Williamson, found only once before in Antarctica, is remarkable for its highly asymmetric cell morphology. The other two species, Cosmarium chapuense and Cosmarium mickeyo...

The ecological relevance of shallow lakes has been largely documented. The Pampean plain (Argentina) holds one of the main wetlands of South America, constituted by thousands of shallow lakes which provide valuable ecosystem services, and can be found in any of three regimes: clear-vegetated, inorganic-turbid or phytoplankton-turbid. Since these la...

Microbial eukaryotes play important roles in aquatic ecosystem functioning. Unravelling their distribution patterns and biogeography provides important baseline information to infer the underlying mechanisms that regulate the biodiversity and complexity of ecosystems. We studied the distribution patterns and factors driving diversity gradients in m...

Mixotrophic protists combine photo-autotrophy and phago-heterotrophy. Even though only in oligotrophic systems mixotrophs overcome strictly autotrophs, they are represented all along the trophic spectrum. We hypothesize that lakes with different chlorophyll a (Chla) and dissolved organic carbon (DOC) concentrations harbor different assemblages of m...

The genus Pseudopedinella has been described as mixotrophic; however, ecological information about this algal stramenopile (Heterokonta) is unclear. We investigate the environmental conditions that determine the presence, abundance and bacterivory rates of this genus in freshwater systems. To this end we analyzed 54 water bodies with different limn...

En este trabajo se presentan los resultados de los estudios realizados en el Río Uruguay durante el período 2013-2014. Se realizaron 105 campañas en 37 sitios entre Bella Unión/Monte Caseros al norte y Nueva Palmira al sur, con una frecuencia semanal en verano y mensual el resto del año. A continuación se presentan las temáticas abordadas en el inf...

We explored the distribution patterns of bacterial and archaeal abundances at the phylum and class level using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), examining the among (across 35 water bodies) and within-lake (intra-annual seasonality) patterns in Patagonia (Argentina). Alphaproteobacteria, Betaproteobacteri...

Bacterioplankton and bacterioperiphyton composition was analyzed using the CARD-FISH technique in three shallow lakes of the Pampean Plain (Argentina) with contrasting regimes: clear vegetated, turbid due to phytoplankton and turbid inorganic, due to inorganic particles. We postulated that these differences would influence the proportion of the mai...

This special issue of Hydrobiologia is devoted to the shallow lakes of the Central Plains of Argentina. The contributors were invited to submit papers dealing with different ecological topics including physical features, climatic and geological characteristics of the region, as well as studies focusing on aquatic communities (fish, zooplankton, phy...

Se exploró la relación entre las fluctuaciones temporales del fitoplancton, las principales variables fisicoquímicas del agua y la estructura del paisaje circundante de cinco lagunas de la cuenca del Rio Salado durante un año. Las lagunas del tramo superior (Gómez y Carpincho) presentaron un patrón de variación fitoplanctónico similar, con gran apo...

We investigated the phytoplankton structure in 60 lakes across a latitudinal gradient (2150 km), from Austral Patagonia to Antarctica, including environments ranging from oligotrophic to eutrophic. We analysed the latitudinal variation of species richness (local and regional) and evenness, as well as the similarity decay in phytoplankton compositio...

AimTo analyse the dependence of phytoplankton species richness on temperature within the framework of the metabolic theory of ecology (MTE) with explicit consideration of its assumptions and predictions.LocationLakes from the Southern Hemisphere - South America (Argentinean Pampa to Tierra del Fuego) and Antarctica - and Northern Hemisphere - North...

We performed a short-term cross-transplant experiment (72 h) using dialysis bags in two shallow lakes with contrasting regimes (clear-vegetated and phytoplankton-turbid). We assessed the changes in the structure of the microbial planktonic communities in response to the variations in the limnological conditions. Important changes were observed in >...

We investigated nine Pampean shallow lakes (Argentina) across a moisture gradient (mean annual precipitation 1,000–500 mm), under the frame-work of a network project of lake monitoring whose main objective was to analyse the responses of ecosystems to different stressors associated with human activities. We postulate that species bloom in different...

We analysed the changes in phytoplankton and in the main limnological features in a shallow lake during its transition from a clear-vegetated regime to a turbid one from 2005 to 2013. As samplings were discontinuous, data were analysed considering three different sampling periods. At the beginning of the first period, the lake was in a clear-vegeta...