Microplastics (MPs) are small, plastic particles of various shapes, sizes and polymers.Although well studied in marine systems, their roles and importance in freshwater environments remain uncertain. Nevertheless, the restricted ranges and variable traits of freshwater fishes result in their communities being important receptors and strong bioindicators of MP pollution. Here, the current knowledge on MPs in freshwater fishes is synthesized, along with the development of recommendations for future research and sample processing. MPs are commonly ingested and passively taken up by numerous freshwater fishes, with ingestion patterns often related to individual traits (e.g. body size, trophic level) and environmental factors (e.g. local urbanization, habitat features). Controlled MP exposure studies highlight various effects on fish physiology, biochemistry and behaviour that are often complex, unpredictable, species-specific and nonlinear in respect of dose-response relationships.Egestion is typically rapid and effective, although particles of a particular shape and/ or size may remain, or translocate across the intestinal wall to other organs via the blood. Regarding future studies, there is a need to understand the interactions of MP pollution with other anthropogenic stressors (e.g. warming, eutrophication), with a concomitant requirement to increase the complexity of studies to enable impact assessment at population, community and ecosystem levels, and to determine whether there are consequences for processes, such as parasite transmission, where MPs could vector parasites or increase infection susceptibility. This knowledge will determine the extent to which MP pollution can be considered a major anthropogenic stressor of freshwaters in this era of global environmental change.

No abstract

No abstract

No abstract

Aims The Oxalate-Carbonate Pathway (OCP) is a biogeochemical process that transfers atmospheric CO 2 into the geologic reservoir as CaCO 3 ; however, until now all investigations on this process have focused on species with limited food benefits. This study evaluates a potential OCP associated with Brosimum alicastrum, a Neotropical species with agroforestry potential (ca. 70-200 kg-nuts yr −1 ), in the calcareous soils of Haiti and Mexico.Methods / results Enzymatic analysis demonstrated significant concentrations of calcium oxalate (5.97 % D.W.) were associated with B. alicastrum tissue in all sample sites. The presence of oxalotrophism was also confirmed with microbiological analyses in both countries. High concentrations of total calcium (>7 g kg −1 ) and lithogenic carbonate obscured the localised alkalinisation and identification of secondary carbonate associated with the OCP at most sample sites, except Ma Rouge, Haiti. Soils adjacent to subjects in Ma Rouge demonstrated an increase in pH (0.63) and CaCO 3 concentration (5.9 %) that, when coupled with root-like secondary carbonate deposits in Mexico, implies that the OCP does also occur in calcareous soils. Conclusions Therefore this study confirms that the OCP also occurs in calcareous soils, adjacent to B. alicastrum, and could play a fundamental and un-accounted role in the global calcium-carbon coupled cycle.

20The contamination of agroecosystems due to the presence of trace elements in commonly 21 used agricultural materials is a serious issue. The most contaminated material is usually 22 sewage sludge and the sustainable use of this material within agriculture is a major concern. 23This study address a key issue in this respect, the fate of trace metals applied to soil in food 24 chains. The work particularly addresses the transfer of Pb, which is an understudied element 25 in this respect and compares the transfer of Pb with two of the most labile metals, Cd and Zn. 26The transfer of these elements was determined from sludge amended soils in a food chain

No abstract

No abstract