scholarly journals Environmental Heterogeneity Determines Diatom Colonisation on Artificial Substrata: Implications for Biomonitoring in Coastal Marine Waters

2021 ◽  
Vol 9 ◽  
Author(s):  
Phumlile Cotiyane-Pondo ◽  
Thomas G. Bornman
Keyword(s):  
Environmental Variability ◽  
Species Turnover ◽  
Experimental Period ◽  
Benthic Diatom ◽  
Artificial Substrates ◽  
Benthic Diatoms ◽  
Diatom Community ◽  
Site Specific ◽  
Artificial Substrata ◽  
Chemical Conditions

Benthic diatoms form an important component of the microphytobenthos and have long been utilised as suitable bioindicators in aquatic systems. However, knowledge on benthic diatom community succession on hard substrata (biofilm) remains understudied in austral marine coastal systems. In this study, we investigated benthic diatom colonisation on artificial substrates (Plexiglass) over a period of 5 weeks at two locations with different physical environments along the warm temperate coast of South Africa. Results revealed relatively similar physico-chemical conditions but highly contrasting diatom community development were observed between the two sites. While there were some shared taxa, site-specific dynamics resulted in significantly different diatom species diversity and richness, facilitated by common (e.g., Nitzschia ventricosa and Cocconeis scutellum) and a large percentage of rarely observed species such as Cocconeis testudo and Lyrella lyra. A total of 134 species belonging to 44 genera were observed during the study. The overall diatom composition differed spatio-temporally during the experimental period, with the fluctuating species occurrences and abundances highlighting the rapid microalgal species turnover within days, under natural conditions. Environmental variables were shown to have varying influences as drivers of the diatom community descriptors. Multivariate modelling confirmed that study site and the interaction between site and sampling occasion were important predictors of diatom abundances, and the overall observed community composition. The current results suggest that benthic diatoms on artificial substrata could be incorporated as suitable indicators of change along the coastline subject to further investigations, taking into account site-specific differences driven by habitat complexity and environmental variability. The experimental method proved to be efficient and can be implemented to study the response of benthic diatoms to localised nutrient enrichment around the coastline.

scholarly journals Relations between Benthic Diatom Community and Characteristics of Karst Ponds in the Alpine Region of Slovenia

Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 531
Author(s):  
Katarina Novak ◽  
Igor Zelnik
Keyword(s):  
Environmental Parameters ◽  
Species Group ◽  
Benthic Diatom ◽  
Alpine Region ◽  
Diatom Species ◽  
Diatom Community ◽  
Total Variability ◽  
Chemical Conditions ◽  
Motile Species ◽  
Physical And Chemical

The aim of this research was to investigate the structure of the benthic diatom community and its relations to selected environmental parameters. We collected samples in 16 karst ponds in the alpine region of Slovenia, where the Alpine karst is found. Since the predominating substrate in these ponds was clay, the epipelic community was analyzed. Hydromorphological characteristics, and physical and chemical conditions were also measured at each site. We found 105 species of diatoms, which belonged to 32 genera. The most frequent taxa were Gomphonema parvulum (Kützing) Kützing, Navicula cryptocephala Kützing, Sellaphora pupula (Kützing) Mereschkowsky (species group) and Achnanthidium pyrenaicum (Hustedt) Kobayasi. The pond with the lowest diversity was found at the highest altitude, while, on the other hand, the most species-rich pond was found at the lowest altitude. Regarding the ecological types, the most common were motile species. We confirmed a positive correlation between the number of diatom species and the saturation of water with oxygen, while correlation between species richness and NH4-N was negative. The content of NO3-N and NH4-N explained almost 20% of the total variability of diatom community. Unlike our expectations, we calculated a negative correlation between the diversity of macroinvertebrates and diatoms, which is probably a consequence of different responses to environmental conditions.

scholarly journals Global pattern of phytoplankton diversity driven by temperature and environmental variability

2019 ◽  
Vol 5 (5) ◽  
pp. eaau6253 ◽  
Author(s):  
Damiano Righetti ◽  
Meike Vogt ◽  
Nicolas Gruber ◽  
Achilleas Psomas ◽  
Niklaus E. Zimmermann
Keyword(s):  
Species Richness ◽  
Environmental Variability ◽  
Species Turnover ◽  
Marine Phytoplankton ◽  
Marine Biodiversity ◽  
Phytoplankton Species ◽  
Global Pattern ◽  
Phytoplankton Diversity ◽  
Biogeographic Patterns ◽  
Theoretical Predictions

Despite their importance to ocean productivity, global patterns of marine phytoplankton diversity remain poorly characterized. Although temperature is considered a key driver of general marine biodiversity, its specific role in phytoplankton diversity has remained unclear. We determined monthly phytoplankton species richness by using niche modeling and >540,000 global phytoplankton observations to predict biogeographic patterns of 536 phytoplankton species. Consistent with metabolic theory, phytoplankton richness in the tropics is about three times that in higher latitudes, with temperature being the most important driver. However, below 19°C, richness is lower than expected, with ~8°– 14°C waters (~35° to 60° latitude) showing the greatest divergence from theoretical predictions. Regions of reduced richness are characterized by maximal species turnover and environmental variability, suggesting that the latter reduces species richness directly, or through enhancing competitive exclusion. The nonmonotonic relationship between phytoplankton richness and temperature suggests unanticipated complexity in responses of marine biodiversity to ocean warming.

Congruence and disparity in benthic diatom community structure of small lakes in New Zealand and Tasmania

2006 ◽  
Vol 57 (8) ◽  
pp. 789 ◽  
Author(s):  
K. Vanhoutte ◽  
E. Verleyen ◽  
K. Sabbe ◽  
C. Kilroy ◽  
M. Sterken ◽  
...  
Keyword(s):  
New Zealand ◽  
Aquatic Ecosystems ◽  
Benthic Diatom ◽  
Diatom Community ◽  
Mountainous Areas ◽  
Small Lakes ◽  
Sodium Potassium ◽  
Community Assemblages ◽  
Ph Range ◽  
Australasian Region

The ecological characteristics of benthic diatom genera from lakes and tarns in mountainous areas of Tasmania (76 lakes) and the South Island (65 lakes) and Stewart Island (6 lakes) of New Zealand were investigated. Community composition and diversity were mainly governed by gradients in calcium, pH and the monovalent/divalent ionic (M/D) ratio, with typical acidophilous and calciphilous communities present in both regions. Highest genus diversity occurred in the pH range between 5.5 and 7.5. Marked interregional differences were present in both calciphilous and acidophilous diatom community assemblages, which were at least partially related to variations in the concentration of the chloride, sodium, potassium and humic substances. Acidophilous communities in New Zealand were typically dominated by Frustulia, Brachysira and Kobayasiella, whereas Eunotia and Actinella dominated in Tasmania. Calciphilous communities in New Zealand were characterised by higher relative abundances of the genera Hantzschia, Diploneis, Nupela, Stauroneis and Synedra, whereas their Tasmanian counterparts were typified by the genera Amphora (subgenus Psammamphora), Biremis, Navicula and Psammothidium. The provinciality of the floras underscores the need for continued protection and conservation of high latitude aquatic ecosystems worldwide and in the Australasian region in particular.

Benthic diatom community response to metal contamination from an abandoned Cu mine: Case study of the Gromolo Torrent (Italy)

2019 ◽  
Vol 75 ◽  
pp. 233-246 ◽  
Author(s):  
Raffaella Tolotti ◽  
Sirio Consani ◽  
Cristina Carbone ◽  
Greta Vagge ◽  
Marco Capello ◽  
...  
Keyword(s):  
Metal Contamination ◽  
Community Response ◽  
Benthic Diatom ◽  
Diatom Community

Intra-annual fluctuations dominating temporal dynamics of benthic diatom assemblages in a Chinese mountainous river

2020 ◽  
Vol 56 ◽  
pp. 22
Author(s):  
Shuhan Guo ◽  
Fengzhi He ◽  
Tao Tang ◽  
Lu Tan ◽  
Qinghua Cai
Keyword(s):  
Community Dynamics ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Multivariate Time Series ◽  
Multiple Scale ◽  
Benthic Diatom ◽  
Diatom Community ◽  
Diatom Communities ◽  
Mountainous River

Understanding temporal dynamics of community may provide insights on biological responses under environmental changes. However, our knowledge on temporal dynamics of river organisms is still limited. In the present study, we employed a multivariate time-series modeling approach with a long-term dataset (i.e. 72 consecutive months) to investigate temporal dynamics of benthic diatom communities in four sites located in a Chinese mountainous river network. We hypothesized that: (1) there are multi-scale temporal dynamics within the diatom community; (2) intra-annual fluctuations dominate the community dynamics; (3) diatom species composing the community respond distinctly to environmental changes. We found that intra-annual fluctuations with periodicities <12 months explained 8.1–16.1% of community variation. In contrast, fluctuations with periodicities of 13–36 months and 37–72 months only accounted for 1.1–5.9% and 2.8–9.7% of variance in diatom community dynamics, respectively. Taxa correlating significantly to each significant RDA axis (namely, RDA taxa group) displayed distinct temporal dynamics. Conductivity, total nitrogen, and pH were important to most RDA taxa groups across the four sites while their effects were group-specific. We concluded that intra-annual dynamics dominated temporal variation in diatom communities due to community responses to local environmental fluctuations. We suggest that long-term monitoring data are valuable for identifying multiple-scale temporal dynamics within biological communities.

scholarly journals Response of Benthic Diatom Assemblages to Contamination by Metals in a Marine Environment

2021 ◽  
Vol 9 (4) ◽  
pp. 443
Author(s):  
Yuriko Jocselin Martínez ◽  
David Alfaro Siqueiros-Beltrones ◽  
Ana Judith Marmolejo-Rodríguez
Keyword(s):  
Species Richness ◽  
Metal Contamination ◽  
Control Site ◽  
Benthic Diatom ◽  
Benthic Diatoms ◽  
Range Effect ◽  
Diatom Assemblages ◽  
Typical Structure ◽  
Medium Range ◽  
Mining Residues

Studies on marine benthic diatoms in environments contaminated by metals are scarce. The typical structure of benthic diatom assemblages (species richness, diversity, dominance, dominant taxa) from undisturbed environments may be used as reference for contrasting with contaminated environments in order to observe how said assemblages respond to such disturbance. Thus, the Ho that the structure of benthic diatom associations and morphology of their frustules under contamination by metals would be normal, as in unpolluted environments was tested. To do this, concentrations of 24 metals were surveyed in a coastal zone impacted by mining residues, and the structure of benthic local diatom assemblages was described. Metal concentrations measurements for 15 metals surpassed the normal values of the upper earth cortex, seven were under the low range effect, and three (Cd, Cu, Zn) surpassed the medium range effect values. At a control site no element concentration was above the reference values for low range effect (LRE) or medium range effect (MRE) standards. There, diatom species richness (S) was high, particularly on seaweeds; where, 397 diatom taxa were recorded. In contrast, at the contaminated area 217 diatom taxa were recorded, but diversity (H’) ranged from 2.4 to 4.3. Relative high frequencies of deformed diatom valves mainly of Achnanthes spp. were recorded in contaminated sediments. In general, diatom taxocenoses presented a typical structure for non-contaminated environments. However, scarceness of specimens, lower S, and frequency of deformed valves suggest responses to metal contamination. For marine environments, the latter values corresponding to A. longipes may be considered a reliable reference to the response of benthic diatoms to metal contamination.

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