Biodiversity of periphyton (diatoms) and echinoderms around a refinery effluent, and possible associations with stability

Izsak, C.; Price, Andrew; Hardy, John S.; Basson, P. W.

doi:10.1080/14634980260199963

Cited by 10 publications

(9 citation statements)

References 27 publications

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“…Similar findings emerged from a recent study of freshwater invertebrates, microflora (diatoms), bryophytes and fish (Heino et al 2005). Apart from this and an earlier study of diatoms (Izsak et al 2002), we are unaware of studies that have comprehensively examined relationships between S and Δ + in aquatic flora. In this study, we analyze a comprehensive benthic algal dataset (species presence/absence) for the Indian Ocean region.…”

Section: Introductionsupporting

confidence: 54%

Concordance between different measures of biodiversity in Indian Ocean macroalgae

Price¹,

Vincent²,

Venkatachalam³

et al. 2006

Mar. Ecol. Prog. Ser.

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We examine relationships between species richness (S), rarity (R) and average taxonomic distinctness (Δ + ) from analysis of a comprehensive dataset for benthic marine algae (including Cyanophyta). This comprises 2894 species from 66 sites across the Indian Ocean. Ranked values for the sites, determined according to the 3 metrics, show significant positive correlation (p ≤ 0.01); Mauritius, India and Aldabra emerge as biodiversity 'hotspots', while Indonesia (Nias Island), Maldives (Male Atoll) and the Gulf of Aden are 'coldspots'. Concordance between metrics was unexpected, given their disparity in robustness to sampling rigour and particularly since Δ + is conceptually unrelated to S and R. Lack of significant latitudinal correlations was also evident except for Δ + , which increased towards temperate waters in the southern hemisphere. This contrasts with the variable patterns observed with longitude, for which significant correlations (negative, i.e. towards the west) were prevalent only for S (algae overall and separate categories except Phaeophyta), evident for R (Cyanophyta only) and absent for Δ + . Hence, use of one floral category as a surrogate for biodiversity in another is not guaranteed. Aquatic biodiversity patterns are complex, in accordance with recent findings derived mainly from faunal datasets. Relationships between different metrics can depend on both the group(s) selected and the environmental or geographical factor(s) examined. Our study is based on analysis of extensive but low resolution (presence/absence) data (Silva et al. 1996) collected from sites of variable size that were not sampled evenly. We address these constraints, but acknowledge the possibility that some patterns may prove to be artefacts, pending analysis of data from recent and ongoing studies. However, we do not expect this to significantly affect our overall conclusions.KEY WORDS: Biodiversity · Species richness · Rarity · Average taxonomic distinctness · Latitudinal and longitudinal patterns · HotspotsResale or republication not permitted without written consent of the publisher

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Section: Introductionsupporting

confidence: 54%

Concordance between different measures of biodiversity in Indian Ocean macroalgae

Price¹,

Vincent²,

Venkatachalam³

et al. 2006

Mar. Ecol. Prog. Ser.

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“…However, responses of biotic indices to environmental conditions are not always predictable. Diversity can decrease with pollution (Rott and Pfister 1988), increase with pollution ( van Dam 1982;Izsak et al 2002), or changes can vary depending on the type of pollution (Ju¨ttner et al 1996;Hillebrand and Sommer 2000;Ju¨ttner et al 2003). Patrick (1973) hypothesized ambiguity in diversity assessment of pollution when using composite diversity because of differing effects of pollutants on species richness and evenness.…”

Section: Introductionmentioning

confidence: 97%

“…But conversion of landscapes into other uses such as agriculture, urban and industrial developments (towns) has altered environmental conditions in rivers with negative effects on their biotic components (Ometo et al 2000;Ju¨ttner et al 2003;Ndaruga et al 2004). Agricultural activities increase inputs of nutrients and sediments (Harding et al 1999;Leland and Porter 2000), residential and commercial estates contribute large quantities of organic wastewater and solids (Lobo et al 1995), while industries are sources of inorganic and thermal pollution (Izsak et al 2002). Although information on the impacts of anthropogenic activities in lotic systems is well documented in developed countries (e.g.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Epilithic Diatoms in Response to Environmental Conditions in an Urban Tropical Stream, Central Kenya

2006

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Use of diatoms in monitoring water quality is well acknowledged in developed countries, but only recently has the assessment started gaining importance in developing countries. Diatoms can be obtained from natural and artificial substrates. Appreciating the differences and similarities of diatom assemblages on both substrates may contribute to a better understanding and standardization particularly during monitoring of water quality. During this study we assessed diatom assemblages, biodiversity and trophic indices in relation to water quality along the Nairobi River. Fifteen sites were sampled in September 2000 during the dry season. Diatoms were collected from natural substrates (stones, pebbles) and artificial substrates (100% acrylic wool). On artificial and natural substrates, a total of 190 and 151 taxa were found, respectively, the majority of these taxa (80%) have cosmopolitan distribution and are also widespread throughout tropical African. Species composition changed downstream, five taxa dominated upper and mid stream sites whereas lower stream sites were dominated by one or two taxa. Species richness, diversity, dominance and evenness were positively correlated with NO 3 , O 2 and altitude but decreased markedly downstream with a simultaneous increase in total dissolved solids, alkalinity, chemical oxygen demand and PO 4 . Ordination and classification (CANOCO and TWINSPAN) showed that diatom assemblages in the Nairobi River responded strongly to water quality changes with respect to concentrations of NO 3 , NO 2 , total dissolved solids and temperature. Taxa common at less impacted upstream sites included Gomphonema gracilis, Anomoeoneis brachysira and Fragilaria biceps; while common taxa at midstream sites with agricultural catchments were Gomphonema parvulum, Navicula cryptocephala, N. schroeteri, N. bryophila, N. halophila, Nitzschia linearis var. linearis and Cymbella silesica. Achnanthes minutissima var. saprophila, Gomphonema angustum, Navicula subminuscula, N. arvensis, Nitzschia palea and N. umbonata were most common at urban sites, which were polluted by residential and industrial effluents. Trophic diatom indices suggested that water quality was poor at most sites in the Nairobi River. Most sites along the river had low Generic Diatom Index values, GDI (<12) and high Trophic Diatom Index values, TDI 73-78 (median = 76) and 75-84 (median = 77) for artificial and natural substrates, respectively. This study showed that diatoms' response on natural and artificial substrates were similar and reflected environmental conditions correctly.

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“…A few studies carried out on the algal flora of lotic ecosystems (e.g., Kufferath, 1957;Gasse et al, 1983;Mpawenayo, 1985Mpawenayo, , 1996 indicate a paucity of information on diatom ecology in Africa. As resident biotic components in streams, diatoms can register and integrate transient or episodic changes of nutrient inputs (Pan et al, 1996), water quality (e.g., Clausen & Biggs, 1997;Chindah, 1998) and general environmental quality, particularly when biodiversity measures sensitive to pollution are also considered (Lobo & Kobayasi, 1990;Izsak et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

The structure of diatom assemblages associated with Cladophora and sediments in a highland stream in Kenya

Mpawenayo

Mathooko

2005

Hydrobiologia

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Epiphytic and epipelic diatoms were collected from six sites in the Njoro River, Kenya, during the dry season between January and March 1997. Diatom assemblage descriptors, such as composition, distribution, species diversity as well as diatom habitat preferences and growth-form guilds were considered. Human activities in the Njoro River watershed included small-scale livestock keeping, subsistence farming, horticultural farming, and canning activities; all these activities have polluted the river. The diatom assemblages found in the Njoro River resembled those of polluted European rivers. The diatom assemblages in the Njoro River comprised eight families and 60 species. Epiphytic diatoms were obtained from the fronds of Cladophora (Cladophoraceae) and the assemblages were richer in species than the epipelic assemblages. Nitzschia amphibia Grun. and Gomphonema parvulum (Ku¨tz.) Grun. were found, either epiphytically and/or epipelically, in all the six sites. Percent similarity index showed that Ng'iria and Beeston sites, and Magadi and Turkana sites, were site pairs that were more similar in diatom composition. Habitat preferences were consistently demonstrated by the diatoms, distributing themselves into epipelic, epiphytic, and/or a combination of these two. The dominant diatom growth-form guild in the Njoro River was the biraphid guild, with the adnate guild being dominant in Mary Joy site, which was frequently disturbed by domestic animals and riparian human communities for water and laundry. This work fills a significant gap in that there is virtually no available data on diatoms in Kenyan streams for comparison. It further emphasizes the importance of macroflora in diversifying habitats of organisms and also in enhancing diversity in streams. Further research on diatom composition, distribution and growth-form guilds in relation to low and high hydrologic regimes is needed to address the role of environmental variability on diatom ecology.

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Biodiversity of periphyton (diatoms) and echinoderms around a refinery effluent, and possible associations with stability

Cited by 10 publications

References 27 publications

Concordance between different measures of biodiversity in Indian Ocean macroalgae

Concordance between different measures of biodiversity in Indian Ocean macroalgae

Distribution of Epilithic Diatoms in Response to Environmental Conditions in an Urban Tropical Stream, Central Kenya

The structure of diatom assemblages associated with Cladophora and sediments in a highland stream in Kenya

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