Quantitative variation of epiphytic diatoms in Galaxaura rugosa (Nemaliales: Rhodophyta)

Abstract

manoel messias da silva costa, sonia maria barreto pereira, patri 'cia campos de arruda and enide eskinazi lec ‚a Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, s / n, Recife, Pernambuco, Brazil This study aimed at describing the quantitative variations of epiphytic diatoms in Rhodophyta Galaxaura rugosa, collected in the Fernando de Noronha archipelago (north-eastern Brazil), during two annual periods (June 2006 and June 2007). The distribution of epiphytic diatoms in G. rugosa confirmed the occurrence of a quantitative variation/zoning along the thallus of the analysed host, with an increase in density (cells per gram wet weight of seaweed) of apical portions towards the basal parts of the seaweed, regardless of the collection points and the annual periods. The abundance was characterized by individuals with pennate symmetry with raphe, belonging to the Bacillariophyceae class. This fact is the result of the host being collected in an insular environment with great water movement under the direct action of trade winds and ocean currents for most of the year. The study confirmed that in marine ecosystems with strong hydrodynamics, epiphytic flora tends to comprise species with the largest adhesive strength.

Microeukaryotic Communities Associated With the Seagrass Zostera marina Are Spatially Structured

“…This, together with the shallower distance-decay slope, corroborates our prediction that seawater microeukaryotes would be highly connected (Fodelianakis et al 2019) and thus more similar in composition than seagrass epibionts at the same spatial scale (Ugarelli et al 2019). The higher variability of seagrass epibiota over short distances could be the result of microspatial gradients of environmental variables such as light and temperature (Perkins et al 2016), exposure to ocean currents, which could select for species with different adhesive strengths (Costa et al 2014;Tanaka 1986), or differences in the microenvironment of leaf surfaces (Papazian et al 2019;Pinckney and Micheli 1998).…”

“…2016), exposure to ocean currents, which could select for species with different adhesive strengths (Costa et al. 2014; Tanaka 1986), or differences in the microenvironment of leaf surfaces (Papazian et al. 2019; Pinckney and Micheli 1998).…”

An Assessment of the Influence of Host Species, Age, and Thallus Part on Kelp-Associated Diatoms

“…Macroalgae may interact with epiphytes on their surfaces by either enhancing or deterring their growth [5,10]. Those effects may be species-specific [10][11][12][13], may be related to the host morphology [6,7,10,14] or the thallus part [10,11,15], and may change throughout the host organism life cycle [16]. For example, nutrients released through the surface of dying Cladophora sp.…”

Do diatoms dominate benthic production in shallow systems? A case study from a mixed seagrass bed

“…Yet, diatoms are prominent in intertidal sediments (Cahoon 2002) where they migrate vertically and contribute to high primary production in macrophyte free areas (Guarini et al 2000). Worldwide, diatoms grow on and add to primary production in kelp (Beltrones et al 2016), maeral (Costa et al 2014), mangrove (Hendrarto and Nitisuparjo 2011), and seagrass (Borowitzka et al 2006) beds.…”