Meiobenthic communities of seagrass beds (Zostera capricorni) and unvegetated sediments along the coast of New South Wales, Australia

Author(s)

Fonseca, Gustavo ^{[1, 2]} ; Hutchings, Pat ^[2] ; Gallucci, Fabiane ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Ctr Biol Marinha, BR-11600000 Sao Sebastiao - Brazil

^[2] Australian Museum, Sydney, NSW 2010 - Australia

• Document type: Journal article
• Source: ESTUARINE COASTAL AND SHELF SCIENCE; v. 91, n. 1, p. 69-77, JAN 1 2011.
• Web of Science Citations: 31

Abstract

Seagrass beds have higher biomass, abundance, diversity and productivity of benthic organisms than unvegetated sediments. However, to date most studies have analysed only the macrofaunal component and ignored the abundant meiofauna present in seagrass meadows. This study was designed to test if meiobenthic communities, especially the free-living nematodes, differed between seagrass beds and unvegetated sediments. Sediment samples from beds of the eelgrass Zostera capricorni and nearby unvegetated sediments were collected in three estuaries along the coast of New South Wales, Australia. Results showed that sediments below the seagrass were finer, with a higher content of organic material and were less oxygenated than sediments without seagrass. Univariate measures of the fauna (i.e. abundance, diversity and taxa richness of total meiofauna and nematode assemblages) did not differ between vegetated and unvegetated sediments. However multivariate analysis of meiofaunal higher taxa showed significant differences between the two habitats, largely due to the presence and absence of certain taxa. Amphipods, tanaidacea, ostracods, hydrozoans and isopods occurred mainly in unvegetated sediments, while kinorhyncs, polychaetes, gastrotrichs and turbellarians were more abundant in vegetated sediments. Regarding the nematode assemblages, 32.4% of the species were restricted to Z. capricorni and 25% only occurred in unvegetated sediments, this suggests that each habitat is characterized by a particular suite of species. Epistrate feeding nematodes were more abundant in seagrass beds, and it is suggested that they graze on the microphytobenthos which accumulates underneath the seagrass. Most of the genera that characterized these estuarine unvegetated sediments are also commonly found on exposed sandy beaches. This may be explained by the fact that Australian estuaries have very little input of freshwater and experience marine conditions for most of the year. This study demonstrates that the seagrass and unvegetated sediments have discrete meiofaunal communities, with little overlap in species composition. (C) 2010 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 10/05472-0 - Free-living marine nematodes: taxonomy, systematics and phylogeny
• Grantee: Gustavo Fernandes Camargo Fonseca
• Support Opportunities: Scholarships in Brazil - Young Researchers
• FAPESP's process: 09/14019-0 - Free living marine nematodes: taxonomy, systematics and phylogeny
• Grantee: Gustavo Fernandes Camargo Fonseca
• Support Opportunities: Research Grants - Young Investigators Grants