Recovery of the algae and macroinvertebrate benthic community after Didymosphenia geminata mass growths in Spanish rivers

Controlling factors affecting the presence and distribution of Didymosphenia geminata in lakes and rivers of the Neuquén province, Argentina

“…According to S.A. Spaulding, Kilroy, & Edlun (), the presence of D. geminata stalks would lead to more homogeneous algal associations, which would lead to less diverse communities. On the contrary, Kilroy et al (), Gillis and Lavoie (), and Sanmiguel et al () found a greater diversity of diatoms and an increase in periphyton biomass associated with D. geminata massive mat formations. The mats can provide a new habitat that enables the development of certain algal species because within these mats, an environment richer in nutrients and extracellular enzymes is created (S. Spaulding & Elwell, ; Sanmiguel et al, ).…”

“…On the contrary, Kilroy et al (), Gillis and Lavoie (), and Sanmiguel et al () found a greater diversity of diatoms and an increase in periphyton biomass associated with D. geminata massive mat formations. The mats can provide a new habitat that enables the development of certain algal species because within these mats, an environment richer in nutrients and extracellular enzymes is created (S. Spaulding & Elwell, ; Sanmiguel et al, ). According to Ladrera, Rieradevall, & Prat (), D. geminata presence creates a community dominated by small organisms causing a significant reduction in the number of diatoms with similar ecological requirements that is clearly different from the existing communities in the streams where D. geminata is absent.…”

“…Bothwell et al, , ; James, Mosel, & Chipps, , J.D.S. Cullis, McKnight, & Spaulding, ; Jackson, Corbett, & Scrimgeour, ; J. Bray et al, ; Sanmiguel et al, )—proved to be important for D. geminata distribution in the Neuquén province. For instance, the statistical binary models in our work indicate that the most important variables related positively to D. geminata occurrence (P/A) were stream order, Mg and SO 4 concentrations, Alk, water temperature, and DO in the waters.…”

“…The importance of Alk in D. geminata occurrence can be evaluated through the pH and the inorganic carbon content in waters (mostly bicarbonates taking into account that the average pH in the environments where D. geminata was found was 7.7). It is well known that D. geminata restricts its presence to environments with a pH range between 7 and 9 (C. Kilroy et al, ; Sanmiguel et al, ). Hix & Murdock () mention two important features related to the pH of the waters: (a) it controls the production of frustules in diatoms because low pH increases Si solubility and (b) it regulates the availability of ions, nutrients, and metals such as P, Ca, Mg, C, and Fe.…”

“…Sanmiguel et al () found that the diatoms Achnanthidium minutissimum and some species of genus Navicula became more abundant during D. geminata mass growth by adapting to live on the stalks of the invasive alga. In our study, these two species seem to have lower abundance in sites where D. geminata is present.…”