Evaluation of Two Ecosystem Services Provided by a Pistia stratiotes Population on the Pacific Coast of South America.

One of the most fascinating wetlands on Peru's central coast is the Santa Rosa wetland (Chancay, Lima), an ecosystem threatened by anthropogenic activities. Some of these impacts have led to the uncontrolled growth of Pistia stratiotes, an invasive aquatic plant. This study sought to quantify the regulation and provisioning of ecosystem services provided by P. stratiotes using carbon storage and the provision of biomass as indicators. To this end, the biomasses of 50 plots measuring 0.0625 m2 were weighed and georeferenced and the percentages of dry biomass (%DB) and total organic carbon in the biomass (%C) were quantified. The biomass and its coordinates were entered into ArcGIS and a Kriging interpolation technique was applied to determine the total amount of biomass (B). It was found that P. stratiotes stored 3942.57 tCO2 and that 2132.41 tons of biomass could be obtained for fodder. The total carbon stored by this aquatic plant represented 28.46% of the total carbon sequestered in the wetland ecosystem by vascular plants, suggesting that its contribution to the carbon cycle is significant. This is the first study to estimate the biomass of a floating aquatic plant population in a coastal Peruvian wetland and is a pioneering study addressing the in situ carbon estimation of Peruvian floating aquatic plants. The results and methods proposed in this research will serve in the evaluation of the potential of ecosystem services among similar populations of floating aquatic species. In addition, the data presented can be used to establish plans for the management and use of this biomass in the production of soil fertilizers and cattle forage.

Bioaccumulation and physiological traits qualify Pistia stratiotes as a suitable species for phytoremediation and bioindication of iron-contaminated water.

Serious concerns have recently been raised regarding the association of Fe excess with neurodegenerative diseases in mammals and nutritional and oxidative disorders in plants. Therefore, the current study aimed to understand the physiological changes induced by Fe excess in Pistia stratiotes, a species often employed in phytoremediation studies. P. stratiotes were subjected to five concentrations of Fe: 0.038 (control), 1.0, 3.0, 5.0 and 7.0 mM. Visual symptoms of Fe-toxicity such as bronzing of leaf edges in 5.0 and 7.0 mM-grown plants were observed after 5 days. Nevertheless, no major changes were observed in photosynthesis-related parameters at this time-point. In contrast, plants growing for 10 days in high Fe concentrations showed decreased chlorophyll concentrations and lower net CO2 assimilation rate. Notwithstanding, P. stratiotes accumulated high amounts of Fe, especially in roots (maximum of 10,000 µg g-1 DW) and displayed a robust induction of the enzymatic antioxidant system. In conclusion, we demonstrated that P. stratiotes can be applied to clean up Fe-contaminated water, as the species displays high Fe bioaccumulation, mostly in root apoplasts, and can maintain physiological processes under Fe excess. Our results further revealed that by monitoring visual symptoms, P. stratiotes could be applied for bioindication purposes.

Year-round phytofiltration lagoon assessment using Pistia stratiotes within a pilot-plant scale biorefinery.

Phytofiltration lagoons are phytoremediation technologies suitable for tropical and sub-tropical regions requiring cost-effective and echo-friendly technologies. A biorefinery of fourth generation has been implemented at pilot plant level in Xalapa, Mexico, and the phytofiltration lagoon, being the first module for provision of treated water and plant biomass for biofuel production plays a key role. The aim of this work was to evaluate the performance of such phytofiltration lagoon with a working volume of 13,000 L for the removal of nutrients from an urban river polluted with domestic wastewater and the biomass productivity of the macrophyte Pistia stratiotes, during five different experimental periods, comprising 42 days each one. The maximum absolute growth rates (AGR, gdwday-1) registered for P. stratiotes during the Aug-Oct '15 and the March-Apr '16 and Apr-May '16 period were in the range of 13.51±2.66 to 16.54±2.02gdwday-1. The average biomass productivity was 5.808gdwm-2day-1. Productivities were similar during the periods of Aug-Oct '15, Mar-Apr '16 and Apr-May '16 and significantly higher (p<0.05) than those registered in Oct-Nov '15 and Jan-Feb '16. Removal percentages of COD and nutrients varied according to the season. COD was in the range of 47.82±39.3% to 88.00±15.0%. Ammonium N was in the range of 76.78±21% to 98.79±0.9%. Nitrates were removed in the range of 16.92±64%. to 97.14±4.5%. Finally, phosphates were removed very effectively, from 73.72±18.5% to 92.89±4.3%. A hydraulic retention time of 7 days was enough for the effective treatment of the water from the polluted river. It was concluded that the phytofiltration lagoon with P. stratiotes is very feasible within the biorefinery for providing biomass year-round and for treating the polluted water very effectively.

Curculionídeos associados à Pistia stratiotes L. (Araceae) na Amazônia Central, com novos registros para Argentinorhynchus Brèthes (Coleoptera, Curculionidae) / Weevils associated with Pistia stratiotes L. (Araceae) in the Central Amazon Region, with new records for Argentinorhynchus Brèthes (Coleoptera, Curculionidae)

São apresentados, pela primeira vez para o Brasil, dados sobre a ocorrência de dez espécies de curculionídeos associadas à Pistia stratiotes L. (Araceae), provenientes da Ilha de Marchantaria, Manaus (Amazonas, Brasil). Durante o período de março a agosto de 2005 foram amostrados 809 espécimens de curculionídeos sobre P. stratiotes, distribuídos em nove espécies alocadas em cinco gêneros de Stenopelmini, e uma espécie não identificada pertencente à Cryptorhynchinae. Dentre os Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) foi a espécie dominante, com a maior abundância em julho (N = 189), e a menor em agosto (N = 11); Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1) e Tanysphiroideus sp. (N = 1) apresentaram abundância inferior. Além disto, registra-se para o Brasil a co-ocorrência de A. breyeri, A. minimus e A. squamosus sobre P. stratiotes, e para o estado do Amazonas, o primeiro registro de A. minimus e A. squamosus.

Data on the occurrence of ten weevils species associated with Pistia stratiotes L. (Araceae), from Ilha de Marchantaria, Manaus (Amazonas, Brazil) are presented for the first time. During the period from March to August 2005, 809 weevils specimens were sampled on P. stratiotes, distributed across nine species allocated in five genera of Stenopelmini, in addition to one unidentified species in the Cryptorhynchinae. Among the Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) was the dominant species, with the highest abundance in July (N = 189) and the lowest in August (N = 11), while Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1), and Tanysphiroideus sp. (N = 1) had lower abundances. In addition, the co-occurrences of A. breyeri, A. minimus, and A. squamosus on P. stratiotes were recorded for Brazil and the first records of A. minimus and A. squamosus were observed for the State of Amazonas.