Average values per zone of total carbon (a), nitrogen (b), phosphate (c), C:N ratio (d), salinity (e) and water content (f).

<p>Carbon, nitrogen en phosphate concentrations (in % w/w) of each sample were normalized for the chlorophyll-<i>a</i> concentration in that sample before averaging.</p

Shannon diversity index (h) of the four different microbial communities averaged per zone.

<p>Shannon diversity index (h) of the four different microbial communities averaged per zone.</p

Sketch of geographical location of the sampling stations (red dots in the insert) at the north-western part of the North Sea coast of the Dutch barrier island Schiermonnikoog.

<p>The stations indicated with ST1, ST2 and ST3 refer to the stations sampled in a previous study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#pone.0063166-Bolhuis1" target="_blank">[10]</a> to which the current dataset is compared. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#s2" target="_blank">Materials and Methods</a> for a description of the stations.</p

RDA plot of bacterial community DGGE profiles of the transect samples along with the most significant environmental parameters (A) and pigments (B).

<p>The ovals around the groups indicated the independent clusters of samples from the different mat types. Eigenvalues for axes 1 and 2 in A are 0.1611 and 0.1163, respectively, accounting for 28% of the total variance and in B are 0.1795 and 0.1082 respectively, accounting for 29% of the variance in the DGGE pattern data.</p

Polymerase chain reaction mixtures and amplification conditions.

1<p>Symbols used: “ = seconds, ‘ = minutes.</p>2<p>Two separate reactions were carried out with 2 different reverse primers (CYA781Ra & CYA781Rb) according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#pone.0063166-Nbel1" target="_blank">[48]</a>. After amplification, samples were pooled, mixed and loaded on the DGGE gel.</p>3<p>A final extension of 30 minutes at 95°C was applied in order to prevent band duplication according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063166#pone.0063166-Janse1" target="_blank">[53]</a>.</p>4<p>en step touch down with annealing temperature decreasing −0.5°C per cycle.</p>5<p>Polymerases used: GE = GE Healthcare <i>Taq</i> polymerase, HS = Qiagen HotStar <i>Taq</i> polymerase.</p

Relative contribution of photosynthetic pigments to the tidal (blue), intermediate (red) and upper (green).

<p>Relative contribution of photosynthetic pigments to the tidal (blue), intermediate (red) and upper (green).</p

Cluster analysis of microbial community fingerprints and concomitant DGGE patterns for a) bacterial community, b) cyanobacterial community, c) eukaryal community and d) archaeal community.

<p>Cluster analysis of microbial community fingerprints and concomitant DGGE patterns for a) bacterial community, b) cyanobacterial community, c) eukaryal community and d) archaeal community.</p

List of oligonucleotides used in this study.

<p><i>Y = C or T, K = G or T.</i></p

Role of fish as predators of mosquito larvae on the floodplain of the Gambia River.

We examined the potential of using native fish species in regulating mosquitoes in the floodplain of the Gambia River, the major source of mosquitoes in rural parts of The Gambia. Fishes and mosquito larvae were sampled along two 2.3-km-long transects, from the landward edge of the floodplain to the river from May to November 2005 to 2007. A semifield trial was used to test the predatory capacity of fish on mosquito larvae and the influence of fish chemical cues on oviposition. In the field, there was less chance of finding culicine larvae where Tilapia guineensis, the most common floodplain fish, were present; however, the presence of anophelines was not related to the presence or absence of any fish species. In semifield trials, both T. guineensis and Epiplatys spilargyreius were effective predators, removing all late-stage culicine and anopheline larvae within 1 d. Fewer culicines oviposited in sites with fish, suggesting that ovipositing culicine females avoid water with fish. In contrast, oviposition by anophelines was unaffected by fish. Our studies show that T. guineensis is a potential candidate for controlling mosquitoes in The Gambia

Dynamics of Hydrology and Anaerobic Hydrocarbon Degrader Communities in A Tar-Oil Contaminated Aquifer

Aquifers are typically perceived as rather stable habitats, characterized by low biogeochemical and microbial community dynamics. Upon contamination, aquifers shift to a perturbed ecological status, in which specialized populations of contaminant degraders establish and mediate aquifer restoration. However, the ecological controls of such degrader populations, and possible feedbacks between hydraulic and microbial habitat components, remain poorly understood. Here, we provide evidence of such couplings, via 4 years of annual sampling of groundwater and sediments across a high-resolution depth-transect of a hydrocarbon plume. Specialized anaerobic degrader populations are known to be established at the reactive fringes of the plume. Here, we show that fluctuations of the groundwater table were paralleled by pronounced dynamics of biogeochemical processes, pollutant degradation, and plume microbiota. Importantly, a switching in maximal relative abundance between dominant degrader populations within the Desulfobulbaceae and Desulfosporosinus spp. was observed after hydraulic dynamics. Thus, functional redundancy amongst anaerobic hydrocarbon degraders could have been relevant in sustaining biodegradation processes after hydraulic fluctuations. These findings contribute to an improved ecological perspective of contaminant plumes as a dynamic microbial habitat, with implications for both monitoring and remediation strategies in situ