Productividad, estado trófico y dinámica fitoplanctónica en la laguna Sauce Grande y su afluente homónimo (pcia. de Buenos Aires, Argentina)

The shallow lake Sauce Grande is located in the southwest of Buenos Aires province. It is a widening of the Sauce Grande River that flows in and out of the lake. The aim of this study is to estimate for the first time the primary productivity (PP) of this lake and to contrast the physiochemical variables, phytoplankton structure and trophic status with those of its main tributary. Monthly samplings (April-September 2014) were performed in the middle basin of the river and on the coast of the lake. We recorded in situ physical and chemical parameters with a multisensor Horiba U-10. Phytoplankton samples were collected with a plankton net for the qualitative study and with plastic bottles for quantitative analysis.The greatest physicochemical differences corresponded to turbidity and conductivity with values of 581.3 NTU and 9 mS/cm for the lake and 17.7 and 1.7, for the river. The average PP in the lake was 252.1 mg C/m3.h. Cyanobacteria were the most abundant taxonomic group in both systems, although its abundance was greater in the shallow lake. The Carlson index, based on the concentration of chlorophyll a and total phosphorus, identifies the lake as eutrophic, while the river was classified as oligo-mesotrophic according to the same variables. Our results suggest that the Sauce Grande Lake is an autotrophic system with a highly productive metabolism. The remaining production becomes biomass and accumulates within the system, in the form of high levels of phytoplankton abundance, in particular a massive proliferation of Cyanobacteria

Evolución del estado trófico y estructura del fitoplancton de un lago somero de la región pampeana: laguna Sauce Grande (Pcia. de Buenos Aires, Argentina)

La laguna Sauce Grande está ubicada en el suroeste de la provincia de Buenos Aires, Argentina, con el río Sauce Grande como afluente y efluente de la misma. El objetivo de este trabajo fue evaluar el estado trófico y las características de la comunidad del fitoplancton de esta laguna. Las muestras de fitoplancton se recolectaron mensualmente y también se midieron los parámetros físico-químicos. El estado trófico del cuerpo de agua se estimó con el índice de estado trófico de Carlson (TSI) basado en la concentración de clorofila a. Bacillariophyta fue el grupo de algas más ampliamente representado en número de taxones para todo el período estudiado. A su vez, Cyanobacteria fue el grupo dominante con Synechocystis salina Wislouch como la especie dominante. La concentración de clorofila a osciló entre 64,6 y 769,4 mg/m3. La abundancia total de fitoplancton varió de 1,6 × 106 a 5,2 × 106 ind /ml y el biovolumen varió de 9,4 × 107 a 1,4 × 109 μm³/ml. La concentración de clorofila a se correlacionó significativamente con la abundancia de fitoplancton, pero no se correlacionó significativamente con el biovolume. Además, el TSI (Cl a) de Carlson osciló entre 70 y 97. En consecuencia, el lago somero Sauce Grande se clasificó como hipertrófico para el período estudiado 2012-2013, mientras que el estado del cuerpo de agua se determinó como eutrófico para el otoño de 2010.Sauce Grande shallow lake is located in the Southwest of the Buenos Aires Province, Argentina, with the river Sauce Grande as both affluent and effluent of it. The aim of this work was to evaluate the trophic state and the characteristics of the phytoplankton community of this shallow lake during an annual cycle. Phytoplankton samples were collected monthly and also physico-chemical parameters were measured. The trophic state of the water body was estimated with Carlson Trophic State Index (TSI) based on chlorophyll a concentration. Bacillariophyta was the algal group most widely represented in number of taxa for the entire studied period. In turn, Cyanobacteria was the dominant group with Synechocystis salina Wislouch as the dominant species. Chlorophyll a concentration ranged between 64.6 and 769.4 mg/m3. The total phytoplankton abundance ranged from 1.6×106 to 5.2×106 ind/ml and the biovolume varied from 9.4×107 to 1.4×109 μm³/ml. The chlorophyll a concentration was significantly correlated with phytoplankton abundance but it was not significantly correlated with biovolume. Besides, Carlson’s TSI (Cl a) ranged from 70 to 97. Accordingly, the Sauce Grande shallow lake was classified as hypertrophic for the studied 2012-2013 period, whereas the status of the water body was determined as eutrophic for the autumn of 2010

Evolución del estado trófico y estructura del fitoplancton de un lago somero de la Región Pampeana: laguna Sauce Grande (provincia de Buenos Aires, Argentina)

Sauce Grande shallow lake is located in the Southwest of the Buenos Aires Province, Argentina, with the river Sauce Grande as both affluent and effluent of it. The aim of this work was to evaluate the trophic state and the characteristics of the phytoplankton community of this shallow lake during an annual cycle. Phytoplankton samples were collected monthly and also physico-chemical parameters were measured. The trophic state of the water body was estimated with Carlson Trophic State Index (TSI) based on chlorophyll a concentration. Bacillariophyta was the algal group most widely represented in number of taxa for the entire studied period. In turn, Cyanobacteria was the dominant group with Synechocystis salina Wislouch as the dominant species. Chlorophyll a concentration ranged between 64.6 and 769.4 mg/m3. The total phytoplankton abundance ranged from 1.6×106 to 5.2×106 ind/ml and the biovolume varied from 9.4×107 to 1.4×109 μm³/ml. The chlorophyll a concentration was significantly correlated with phytoplankton abundance but it was not significantly correlated with biovolume. Besides, Carlson’s TSI (Cl a) ranged from 70 to 97. Accordingly, the Sauce Grande shallow lake was classified as hypertrophic for the studied 2012- 2013 period, whereas the status of the water body was determined as eutrophic for the autumn of 2010.Facultad de Ciencias Naturales y Muse

Evolución del estado trófico y estructura del fitoplancton de un lago somero de la Región Pampeana: laguna Sauce Grande (provincia de Buenos Aires, Argentina)

Sauce Grande shallow lake is located in the Southwest of the Buenos Aires Province, Argentina, with the river Sauce Grande as both affluent and effluent of it. The aim of this work was to evaluate the trophic state and the characteristics of the phytoplankton community of this shallow lake during an annual cycle. Phytoplankton samples were collected monthly and also physico-chemical parameters were measured. The trophic state of the water body was estimated with Carlson Trophic State Index (TSI) based on chlorophyll a concentration. Bacillariophyta was the algal group most widely represented in number of taxa for the entire studied period. In turn, Cyanobacteria was the dominant group with Synechocystis salina Wislouch as the dominant species. Chlorophyll a concentration ranged between 64.6 and 769.4 mg/m3. The total phytoplankton abundance ranged from 1.6×106 to 5.2×106 ind/ml and the biovolume varied from 9.4×107 to 1.4×109 μm³/ml. The chlorophyll a concentration was significantly correlated with phytoplankton abundance but it was not significantly correlated with biovolume. Besides, Carlson’s TSI (Cl a) ranged from 70 to 97. Accordingly, the Sauce Grande shallow lake was classified as hypertrophic for the studied 2012- 2013 period, whereas the status of the water body was determined as eutrophic for the autumn of 2010.Facultad de Ciencias Naturales y Muse

The impact of associated tenotomies on the outcome of incomplete phalangeal osteotomies for lesser toe deformities

Partial or incomplete osteotomy (IO) of the phalanx is recently described in the literature. However, the clinical outcome and the rate of complications when applied to lesser toe deformities (LTD) have been never addressed. This study aims to find out if the association of tenotomies to incomplete or partial phalanx osteotomies has a significant impact on the clinical outcomes, the occurrence of complications, and the recovery time after surgery. Methods: A retrospective review of two cohorts of cases operated in our institution for hallux abductus valgus (HAV) and associated LTD from 2008 to 2014 was carried out. The surgical correction of both HAV and the associated LTD was always performed by minimally invasive techniques. The study included a total of 223 patients (723 IO in 556 toes). In 129 cases, the IO for LTD correction was performed without tenotomies, and in 94, the procedure was combined with flexor and/or extensor tenotomies. Patients were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) questionnaire before surgery and at 6- and 12-month follow-up. Results: The mean preoperative AOFAS score before surgery was similar in both cohorts. At 12-month follow-up, the cohort without tenotomies showed better recovery (95.7 ± 2.8 versus 92.5 ± 6.8; p < 0.01). AOFAS scores decreased as the number of associated LTD increased (r = − 0.814; p < 0.001). Cases operated on by PO + tenotomy showed a high rate of complications such as delayed union of the osteotomy (p < 0.01), hypertrophic callus (p < 0.01), phalangeal fracture at the osteotomy site (p < 0.01), and lack of correction (p < 0.05). The overall occurrence of adverse events was 38.6% in cases operated by PO + tenotomy and 13.9% in cases receiving PO alone (p < 0.0001). Cases operated on without tenotomy showed a shorter time to complete recovery for daily life activities (37.4 ± 2.3 versus 43.0 ± 1.7 days; p < 0.01). Conclusion: The performance of associated tenotomies to incomplete phalanx osteotomies provides worse clinical outcomes, higher complication rates, and longer recovery time as compared to similar forefoot surgeries without tenotomies.Podologí