Size of Dominant Diatom Species Can Alter Their Evenness

Abstract

Traditionally, biodiversity has often been estimated on the basis of abundance partly due to the need for complicated measurements of biomass. Here, we conducted robust measurements of the community composition and of the size structure of diatoms in the North Pacific to evaluate the importance of biomass on the biodiversity. We found that the two most useful evenness indices increased in most cases where small species were numerically dominant when calculations were based on biomass compared with those on abundance. Size-abundance spectra of diatoms revealed that numerically dominant small species rarely dominated in terms of biomass. On the other hand, intermediate to large diatom species generally played a dominant role in terms of biomass in diatom community. The results suggest that the size of the dominant species is a crucial factor in determining the role of diatoms in the ecosystem functioning. Because such size variability can also be observed in other organisms, we need to pay attention to the effect of size structures on biodiversity.

Size scaling patterns of species richness and carbon biomass for marine phytoplankton functional groups

“…() for the size range of nanophytoplankton. In contrast, a positive cell size–carbon biomass relationship has been described by Sugie and Suzuki () for diatoms and by Jakobsen, Carstensen, Harrison, and Zingone () for diatoms and for the entire (ataxonomic) community. Several authors have claimed that large phytoplankton cells are the main drivers of change in phytoplankton carbon biomass (Huete‐Ortega, Marañón, Varela, & Bode, ).…”

“…However, data on marine phytoplankton species richness–cell size histogram spectra are scarce and controversial. Downing, Hajdu, Hjerne, Otto, and Blenckner () reported multimodal size frequency distributions of Baltic Sea phytoplankton and Sugie and Suzuki () described the unimodal distribution in the size histogram of North Pacific diatoms, while Sabetta et al. () presented phytoplankton histogram size spectra showing a pattern of bell‐shaped unimodal distribution.…”

“…Hajdu, Hjerne, Otto, and Blenckner (2014) reported multimodal size frequency distributions of Baltic Sea phytoplankton andSugie and Suzuki (2015) described the unimodal distribution in the size histogram of North Pacific diatoms, whileSabetta et al (2005) presented phytoplankton histogram size spectra showing a pattern of bell-shaped unimodal distribution. It is obvious that extended research is required for resolution of the species richness-cell size frequency distribution patterns.Regression analysis of log-transformed species richness-cell size values in this work indicated the existence of a continuous linear model and sequence regularity in size along the taxonomic and F I G U R E 4 Relationships among cell abundance, carbon biomass and cell volume for taxonomic (diatoms, dinoflagellates, coccolithophores) and ataxonomic (nano-micro-macrophytoplankton) size classes F I G U R E 3 Carbon biomass-cell size spectra representing the best fit (linear regression) to log-transformed values of these variables for taxonomic(diatoms, dinoflagellates, coccolithophores) and ataxonomic (nano-micromacrophytoplanktonThe obtained linear curves had common patterns, independent of taxonomic or ataxonomic affiliation.…”

Comparative responses of dominant and subordinate periphytic diatom species to environmental gradients in Donghu Lake, China

“…Dominant or core species represented species which dominate in many different conditions, and the others were called subordinate species (Olff and Bakker, ). Generally, dominant species obtained the most attention as bio‐indicators because of their obvious abundance (Kang et al, ; Sugie and Suzuki, ). By contrast, few researchers were willing to focus on the subordinate or rare species (Mi et al, ; Bennett and Arcese, ; Markham, ).…”

Impacts of Temperature, CO2, and Salinity on Phytoplankton Community Composition in the Western Arctic Ocean

“…The cell volume was estimated based on the geometric similarity (Hillebrand et al, 1999) and then converted into carbon biomass using an allometric relationship (Menden-Deuer and Lessard, 2000). The diversity of diatoms was estimated by the Shannon-Weiner (H ) index using biomass data (Tuomisto, 2010;Sugie and Suzuki, 2015). The use of an index that is based on estimates of biomass and not abundance is particularly appropriate when organisms of interest have a large variability in size, such as diatoms Suzuki, 2015, 2017).…”