A new method for analyzing microplastic particle size distribution in marine environmental samples

Microplastics (MPs) are recognized as a global emerging threat to aquatic ecosystems and biodiversity worldwide. Though the number of publications and interest to the MP research have been increased rapidly, it is still hamper to compare the obtained data due to the usage of different methodologies in MP assay. Thus, there is an urgent need for a standardized approach to the procedures of MP quantification in order to produce comparative assessments. In this pilot study, the conventional NOAA protocol of MP extraction from seawater was combined with a simple and inexpensive method for analyzing shape and size spectrum of all MP particles making up the sample. A common flatbed scanner equipped with slide adapter was applied for image acquisition while MP dispersive properties (particle abundance, shape and size spectrum) were quantified using ImageJ software. Feret’s diameter and circularity (or roundness) appeared to be the most efficient shape descriptors for the particle analysis. The total silhouette area of MP particles was shown to produce a confident approximation of the MP overall mass. The first reliable estimates of MP concentrations in the Black Sea coastal waters (Sevastopol Bay) accounted for 0.6 to 7 items m-3 and 6 to750 µg m-3 in terms of abundance and mass, respectively. No steady-state gradients have been revealed in MP distribution along the transect from the mouth of the bay to its corner. Inflow of MP to the bay waters and their transport along the bay seemed to be controlled by a complex combination of factors including rainfalls, wind regimes, currents and the Black river discharge.

Rootstock Affects Yield, Yield Efficiency, and Harvest Rate of 'Kensington Pride' Mango

Low yields and high harvesting costs are long-standing problems in mango (Mangifera indica L.) cultivation. In an effort to increase productivity in the scion 'Kensington Pride' we examined the impact of nine different rootstocks over a 10-year period. Rootstock effects on fruit production were significant in most seasons, and cumulative yields (nine seasons of cropping) for the best treatment ('Sg. Siput') exceeded those of the poorest treatment ('Sabre') by 141%. Yield efficiencies (expressed on both a trunk cross-sectional area and canopy silhouette area basis) were also significantly affected by rootstock. Rootstock effects on yield and yield efficiency were generally consistent across seasons, despite large seasonal variations in yield. Harvest rates were also influenced by rootstock, and were poorly correlated with tree size. These results demonstrate possibilities for manipulating mango scion productivity through rootstock genotype.

Use of a video-imaging system for estimating leaf surface area of Pinussylvestris seedlings

A method is described for a rapid, nondestructive estimation of the surface area of the shoot system of intact pine seedlings. A video camera and image analyzer were used to quantify the area of a video image of pine seedling shoots. Surface area values were displayed in dimensionless units, referred to as silhouette area. Silhouette area was significantly correlated with several other methods of estimating needle surface area, including dry weight, calculation based on measurement of linear dimensions, volume displacement, and optical planimetry. Correspondence between dry weight, or surface area estimates based on dry weight, and silhouette area was relatively low (r2 < 0.9) but statistically significant. The correlation between shoot area and silhouette area were improved (r2 > 0.9) when shoot area was estimated from volume displacement or optical planimetry.