Fungal community structure at the soil surface under light and dark conditions.

<p>The diversity and abundance of fungi (ITS region) at the soil surface of a pasture soil after 80 days incubation under light or dark conditions. Data is presented in MEGAN as an OTU table created in QIIME at a 97% similarity threshold (uclust). The number of reads that can be assigned using the RDP classifier at a confidence level of 80% to each taxon are shown at the end of each node. Pie charts show the proportion of reads assigned to each sample incubated under light (green) and dark (brown) conditions with replicates shown as shades of these colours. Significant differences in the read abundance of sequences between light and dark samples are highlighted in green when abundance is significantly higher under light conditions and in blue when abundance is significantly higher under dark conditions (p<0.05).</p

Relative read abundance of sequences with close homology to cyanobacteria and eukaryotic phototrophs from the soil surface of a pasture soil after incubation under light or dark conditions for 80 days (±1 standard error).

<p>Significant differences between light and dark treatments is indicated by a *(p≤0.05) or **(p≤0.01).</p

The effect of light and depth on chlorophyll <i>a</i>, most probable number (MPN) of algae, pH, and extractable nitrate, phosphorus, potassium and magnesium after 80 days incubation under light and dark conditions (±1 standard error).

<p>Significant differences between treatments are indicated by different letters (p≤0.01).</p

Chlorophyll <i>a</i> development in Gartenacker soil.

<p>Chlorophyll <i>a</i> in the surface (▴) and bulk (▾) of pasture soil after incubation under light (open symbols) or dark (closed symbols) conditions. Errors bars are ±1 standard error.</p

Bacterial community structure at the soil surface under light and dark conditions.

<p>The diversity and abundance of bacteria (16S rRNA gene) at the soil surface of a pasture soil after 80 days incubation under light or dark conditions. Data is presented in MEGAN as an OTU table created in QIIME at a 97% similarity threshold (uclust). The OTU table is presented at the taxonomic level of family. The number of reads that can be assigned using the RDP classifier at a confidence level of 80% are shown at the end of each node. Pie charts show the proportion of reads assigned to each sample incubated under light (green) and dark (brown) conditions with replicates shown as shades of these colours. Taxonomic assignments accounting for <0.5% total sequence abundance were removed. Significant differences in the read abundance of sequences between light and dark samples are highlighted in green when abundance is significantly higher under light conditions and in blue when abundance is significantly higher under dark conditions (p<0.05).</p

Phototroph diversity at the soil surface under light and dark conditions.

<p>α diversity estimates Chao1 (a) and Observed Species (b) and non-metric multidimensional scaling of community structure similarity (c) for phototrophs (23S rRNA genes of plastids) at the soil surface of a pasture soil after 80 days incubation under light (open symbols) or dark (closed symbols) conditions. OTU clustering was performed at the 97% similarity threshold using UCLUST. Error bars are ±1 S.E. Non-metric multidimensional scaling shows clustering based on the similarity of microbial community structure between treatments: 20% (red cluster), 25% (black cluster) and 80% (blue cluster).</p

Fungal diversity at the soil surface under light and dark conditions.

<p>α diversity estimates Chao1 (a) and Observed Species (b) and non-metric multidimensional scaling of community structure similarity (c) for fungi (ITS region) at the soil surface of a pasture soil after 80 incubation under light (open symbols) or dark (closed symbols) conditions. OTU clustering was performed at the 97% similarity threshold using UCLUST. Error bars are ±1 S.E. Non-metric multidimensional scaling shows clustering based on the similarity of microbial community structure between treatments: 55% (red cluster) and 70% (black cluster).</p

Non-UV Light Influences the Degradation Rate of Crop Protection Products

Crop protection products (CPPs) are subject to strict regulatory evaluation, including laboratory and field trials, prior to approval for commercial use. Laboratory tests lack environmental realism, while field trials are difficult to control. Addition of environmental complexity to laboratory systems is therefore desirable to mimic a field environment more effectively. We investigated the effect of non-UV light on the degradation of eight CPPs (chlorotoluron, prometryn, cinosulfuron, imidacloprid, lufenuron, propiconazole, fludioxonil, and benzovindiflupyr) by addition of non-UV light to standard OECD 307 guidelines. Time taken for 50% degradation of benzovindiflupyr was halved from 373 to 183 days with the inclusion of light. Similarly, time taken for 90% degradation of chlorotoluron decreased from 79 to 35 days under light conditions. Significant reductions in extractable parent compound occurred under light conditions for prometryn (4%), imidacloprid (8%), and fludioxonil (24%) compared to dark controls. However, a significantly slower rate of cinosulfuron (14%) transformation was observed under light compared to dark conditions. Under light conditions, nonextractable residues were significantly higher for seven of the CPPs. Soil biological and chemical analyses suggest that light stimulates phototroph growth, which may directly and/or indirectly impact CPP degradation rates. The results of this study strongly suggest that light is an important parameter affecting CPP degradation, and inclusion of light into regulatory studies may enhance their environmental realism