Цит. [Pandey et al., 2017]:

Ответ: явная связь отсутствует

Diatom diversity indices and their relative abundance in the diatom communities are widely used to indicate the presence and extent of organic and inorganic contaminants in fluvial ecosystems. In most studies,

these routinely used indices provide a statistically weak relationship between diatom diversity and pollutants.

Thus, in the light of this result,

there is an urgent need to incorporate new types of diatom-based indices

(e. g., a taxonomic composition based index), which can provide reliable information using statistical tools. Improvement in taxonomic resolution of diatom species, use of composite indices (richness, evenness, diversity and dominance), increased cell counting (3000-8000 valves) and simultaneous use of several indices to detect and evaluate the huge spectrum of potential pollutants have been proposed to improve the efficacy of diatom-based ecotoxicological assessments [Blanco and Becares, 2010; Stevenson et al., 2010; Rimet and Bouchez, 2011].

Нет прямого влияния химических загрязнений на разнообразие диатомовых

Analysis of available literature does not support a direct causeeffect relationship between chemical pollution and diatom diversity.

In general,

the relationship between diversity and chemical contamination is not always a simple linear positive/negative association and results are not always strong enough to indicate a management approach that would most effectively conserve the health of the ecosystem.

<...>

These biodiversity parameters are regularly used but sometimes do not provide consistent information about the known impairment of waterbodies [Blanco et al., 2012].

<...>

Other studies showed mixed responses of diatoms against different types of stresses.

<...>

This inconsistency of diatom diversity indices and lack of significant correlations between diversity, evenness and environmental variables is in accordance with the “Intermediate Disturbance Hypothesis”, which assumes a parabolic relation between diversity and water quality, with the highest diatom diversity at intermediate pollution levels [Van de Vijver and Beyens, 1998; Hirst et al., 2002].

Как выявить потенциальную взаимосвязь

Используйте несколько индексов разнообразия

Ricciardi et al. (2009) reviewed the status of biological communities in rivers in relation to chemical contamination and reported two major constrains in diversity and pollution studies.

• First, they found that the use of a single diversity index or small number of diversity indices was inadequate. The different biodiversity indices assess different types of information and using only one of these indices (types of information) is not enough to adequately define biological diversity. Multivariate-analysis studies that combine both conventional and taxonomy-based indices and possibly different trophic levels provide a more comprehensive view of the diversity status of an ecosystem and its potential response to pollutants.
• Second, they advocated the use of coupled chemical and biological analyses to evaluate water-quality status and the effect of chemicals on fluvial biological diversity, thus promoting a multidisciplinary approach.
• Further, they recommended incorporating a variety of types of biodiversity indices, especially when using algae (diatoms) for assessing the chemical status of aquatic systems.

According to Stevenson et al. (2010), composite indices that incorporate both the richness and evenness elements of diversity are needed to characterize the kind and severity of pollution in fluvial ecosystems. Similarly, Blanco and Becares (2010) found that the simultaneous use of several diatom indices is required to detect and evaluate the huge spectrum of potential pollutants in river basins.

Применяйте методы понижения размерности

Relative abundance data can become informative through the use of ordination, clustering and similarity indices [Stevenson et al., 2010].

More specifically, ordination-based multivariate analysis (e. g., correspondence analysis, detrended correspondence analysis, non-metric multidimensional scaling, principal component analysis and distance-based redundancy analysis) was developed to relate community composition to measured variation in the environment.

• Ordination plots obtained in the analyses are linear combinations of environmental variables, along which the relative distributions of species assemblages.
• Ordination plots help in visualizing the pattern of community variation, distributions of species and assemblages among environmental variations, and can be used for indicating species-environment relationships. (ter Braak, 1986; ter Braak, 1987; ter Braak and Smilauer, 2002).
• Furthermore, ordination and clustering can be used to show assemblages that differ from other assemblages, which may be caused by anthropogenic impacts (e. g. Chessman, 1986; Stevenson and White, 1995).

Thus, incorporation of these analyses (any one) provides a simple, easy-to-understand description of the percent change in species relative abundances between assemblages at assessed and reference sites.

Процитирован

Pandey L. K., Bergey E. A., Lyu J., Park J., Choi S., Lee H., Depuydt S., Oh Y.-T., Lee S.-M., Han T. (2017) The use of diatoms in ecotoxicology and bioassessment: Insights, advances and challenges. Water Research. 118: 39-58.