Are algal communities driven toward maximum biomass?

Passy, Sophia I.; Legendre, Pierre

doi:10.1098/rspb.2006.3632

Cited by 21 publications

(22 citation statements)

References 50 publications

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“…2 is in the series of lakes that show particularly high planktonic biovolumes at relatively low to intermediate levels of diversity. This result is in agreement with work on stream communities by Passy & Legendre (2006), who demonstrated that biovolumes should peak at intermediate to high levels of species diversity in the benthos, but at low levels of species diversity in the plankton. They attributed this difference to the higher niche dimensionality of benthic habitats relative to comparably more homogenous planktonic zones.…”

Section: Discussionsupporting

confidence: 92%

Functional diversity is positively associated with biomass for lake diatoms

2010

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1. Recent work has emphasised the benefit of using functional measures when relating biodiversity to ecosystem functioning. In this study, we investigated the extent to which functional and taxonomic diversity might be related to summed biovolume in community assemblages of 212 species of diatoms collected from 65 temperate lakes in western and central Quebec, Canada. 2. We quantified functional diversity as both the total path-length of a functional dendrogram (FD) and the variance in species traits (TV) for a given community. Selected traits included both size and responses to a set of environmental variables known to be influential for diatom communities. 3. Species richness, as well as both FD and TV, was positively associated with total diatom biovolume at the level of the entire diatom community, suggesting that diversity in response types (particularly to total phosphorus and pH) is important for diatom community production. 4. Although functional measures of diversity did not provide enhanced explanatory power over species richness, we argue that an exploration of functional traits potentially allows greater insight into the mechanisms underlying biodiversity-ecosystem functioning relations, indicating which traits might be most influential in driving community biomass production.

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Section: Discussionsupporting

confidence: 92%

Functional diversity is positively associated with biomass for lake diatoms

2010

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“…Apart from turbulent water motion and circulation, which homogenize the planktonic environment, the nutrient gradients in the plankton are further disrupted by the sinking of the algae (39). These fundamental differences between benthic and planktonic habitats in terms of number and length of the resource gradients have been implicated in the profound disparity between the two communities in taxonomic and allometric organization and functioning (40)(41)(42). Therefore, lacking the complex gradient structure of the benthos, the phytoplankton was expected to respond to nutrient enrichment like a 2D community.…”

Section: Resultsmentioning

confidence: 99%

“…Diatom richness was calculated as the number of species in 300 cell counts. More information on the habitats, sampling, and laboratory techniques is given in Passy and Legendre (41). Diatom richness was regressed against NLR in the three studied habitats by using a curve-fitting program (45).…”

Section: Methodsmentioning

confidence: 99%

Continental diatom biodiversity in stream benthos declines as more nutrients become limiting

Passy

2008

Proc. Natl. Acad. Sci. U.S.A.

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Biodiversity of both terrestrial ecosystems and lacustrine phytoplankton increases with niche dimensionality, which can be determined by the number of limiting resources (NLR) in the environment. In the present continental study, I tested whether niche dimensionality and, with this species, richness scale positively with NLR in running waters. Diatom richness in 2,426 benthic and 383 planktonic communities from 760 and 127 distinct localities, respectively, was examined as a function of NLR, including basic cations, silica, iron, ammonia, nitrate, and dissolved phosphorus. The patterns found in the two communities were opposite: as more resources became limiting, diatom richness declined in the benthos but increased in the phytoplankton. The divergence of benthic from both planktonic and terrestrial communities is attributed to the complex spatial organization of the benthos, generating strong internal resource gradients. Differential stress tolerance among benthic diatoms allows substantial overgrowth, which greatly reduces nutrient transport to the biofilm base and can be supported only by high ambient resource levels. Therefore, niche dimensionality in the benthos increases with the number of resources at high supply. These findings provide a mechanistic explanation of the well documented phenomenon of increased species richness after fertilization in freshwater as opposed to terrestrial ecosystems. Clearly, however, new theoretical approaches, retaining resource availability as an environmental constraint but incorporating a trade-off between tolerance and spatial positioning, are necessary to address coexistence in one of the major producer communities in streams, the algae.

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“…The environmental implications of this finding are far reaching because it reveals that a continuing loss of wetlands, already exceeding 52 million hectares in the conterminous United States alone (Mitsch and Gosselink 2007), may lead to algal biodiversity decline in streams with a subsequent reduction in primary productivity and biomass (Cardinale et al 2005, Passy andLegendre 2006 ). It is expected that stream ecosystem health will improve with wetland restoration that produces sufficient amounts of soil organic matter, DOC, and iron in the watershed and facilitates micronutrient fluxes into streams.…”

Section: Discussionmentioning

confidence: 99%

A distinct latitudinal gradient of diatom diversity is linked to resource supply

Passy

2010

Ecology

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Abstract. For over 200 years, scientists have recognized the nearly ubiquitous poleward decline of species richness, but none of the theories explaining its occurrence has been widely accepted. In this continental study of U.S. running waters, I report an exception to this general pattern, i.e., a U-shaped latitudinal distribution of diatom richness (DR), equally high in subtropical and temperate regions. This gradient is linked unequivocally to corresponding trends in basin and stream properties with impact on resource supply. Specifically, DR distribution was related to wetland area, soil composition, and forest cover in the watershed, which affected iron, manganese, and macronutrient fluxes into streams. These results imply that the large-scale biodiversity patterns of freshwater protists, which are seasonal, highly dispersive, and sheltered by their environment from extreme temperature fluctuations, are resource driven in contrast to more advanced, perennial, and terrestrial organisms with biogeography strongly influenced by climate. The finding that wetlands, through iron export, control DR in streams has important environmental implications. It suggests that wetlands loss, already exceeding 52 million hectares in the conterminous United States alone, poses a threat not only to local biota, but also to biodiversity of major stream producers with potentially harmful consequences for the entire ecosystem.

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Are algal communities driven toward maximum biomass?

Cited by 21 publications

References 50 publications

Functional diversity is positively associated with biomass for lake diatoms

Functional diversity is positively associated with biomass for lake diatoms

Continental diatom biodiversity in stream benthos declines as more nutrients become limiting

A distinct latitudinal gradient of diatom diversity is linked to resource supply

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