@article {Somerfield:2007yf,
	title = {Three-dimensional spatial structure: nematodes in a sandy tidal flat},
	journal = {Marine Ecology-Progress Series},
	volume = {336},
	year = {2007},
	pages = {177-186},
	publisher = {INTER-RESEARCH},
	address = {NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY},
	abstract = {Benthic infauna live in a three-dimensional world, and patterns of horizontal distribution may vary with depth in the sediment, as may the mechanisms that determine those patterns. This study examines how horizontal spatial structure varies with depth in a semi-exposed coarse-sand flat adjacent to St Martin{\textquoteright}s, one of the Isles of Scilly, UK. Nematode samples were collected from 3 sediment depth horizons (0 to 5, 5 to 10 and 10 to 15 cm) in a nested hierarchical design, with samples 0.1, 1 and 10 m apart. Results show that spatial patterns are strongest amongst samples of intermediate depth (5 to 11) cm), and generally insignificant amongst samples collected from 10 to 15 cm. There is short-order spatial autocorrelation in surface (0 to 5 cm) samples, with samples collected 10 cm apart being significantly more alike than samples collected further apart. We postulate that this is because spatial structure of nematodes in surface sediments is determined by patchiness induced by interactions between the water column and the physical structure of the surface layers of the sediment, which are constantly reworked by wind and tides. The deeper layers, 10 to 15 cm below the surface, are constantly reworked by a dense population of heart urchins Echinocardium cordatum. It is only in the intermediate horizon that relatively stable conditions allow nematode assemblages to establish spatial structure over a range of scales. It is concluded that the interaction between sediment permeability, and therefore interfacial advection, and bioturbation in controlling infaunal diversity and spatial patterns is potentially important.},
	keywords = {advection, bioturbation, Echinocardium, nematodes, spatial structure, vertical distribution},
	author = {Somerfield, P. J. and Dashfield, S. L. and Warwick, R. M.}
}
@article {Hourston:2009rc,
	title = {Spatial and seasonal variations in the ecological characteristics of the free-living nematode assemblages in a large microtidal estuary},
	journal = {Estuarine Coastal and Shelf Science},
	volume = {82},
	year = {2009},
	pages = {309-322},
	publisher = {ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD},
	address = {24-28 OVAL RD, LONDON NW1 7DX, ENGLAND},
	abstract = {This study has determined the ways in which the density, number of species, species composition and trophic structure of free-living nematode assemblages in the subtidal waters of a large southern hemisphere microtidal estuary change spatially and seasonally, and has explored whether those four biotic characteristics are related to certain environmental factors. Based on data derived from samples collected seasonally at 12 sites throughout the estuary, the densities and number of species of nematodes decreased progressively with distance from estuary mouth, to reach a minimum at sites where salinities were most variable. and then increased slightly in the uppermost part of the estuary where salinities were least. Densities were also generally greatest in spring, due largely to increases in the abundance of epistrate-grazing species at this time and thus when the amount of primary food (microphytobenthos) peaked. The spatial distribution of the composition of the nematode assemblages was closely correlated with salinity and, to a lesser extent, grain-size composition and amount of particulate organic material (\%POM) in the sediment. Although species composition changed sequentially along the estuary, the change was particularly pronounced between sites above and below the area where salinities started to decline markedly and become more variable and \%POM increased markedly. This reflected, in particular, far greater abundances of Spirinia parasitifera at the six downstream sites and of Theristus sp. 1 at the six sites further upstream. Species composition underwent pronounced seasonal cyclical changes at all sites, presumably reflecting interspecific differences in the timing of peak reproduction and thus of recruitment. The trophic structure of the nematode assemblages changed both spatially and temporally in relation to the relative abundance of different food sources. Thus, for example, non-selective deposit feeders, such as Theristus sp. 1, dominated samples in the upper estuary, where \%POM was by far the greatest, and was rare or absent at downstream sites. Conversely, epistrate grazers, such as species of the Chromadoridae, were most abundant at downstream sites in spring, when the density of the microphytobenthos reached its maximum. (C) 2009 Elsevier Ltd. All rights reserved.},
	keywords = {environmental factors, microtidal estuary, nematodes, number of species and density, species and trophic compositions},
	doi = {DOI 10.1016/j.ecss.2009.01.018},
	author = {Hourston, M. and Potter, I. C. and Warwick, R. M. and Valesini, F. J. and Clarke, K. R.}
}
@booklet {Gobin:2006sf,
	title = {Geographical variation in species diversity: A comparison of marine polychaetes and nematodes},
	volume = {330},
	year = {2006},
	note = {Journal of Experimental Marine Biology and Ecology},
	pages = {234-244},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {The aim of this study was to determine if marine species diversity was influenced by geographical location and whether it was higher at lower latitudes. Artificial collectors (made of nylon pan scourers) were employed as a standard substratum for the colonisation of marine invertebrates inhabiting subtidal (12 to 15 m) hard, rocky bottom substrata. These artificial substrate units (ASUs) were deployed at different latitudes including northern and southern temperate (South West England, UK and New Zealand), tropical (Trinidad and Tobago, West Indies) and polar (Signy Island, Antarctica) areas. The polychaetes, representative of the macrofauna and the nematodes, representative of the meiofauna fractions of the total invertebrate fauna collected were analysed. Neither polychaete nor nematode species diversity showed a trend based on latitude and each taxon showed a different pattern of diversity variation in relation to location. Polychaete diversity varied from area to area with highest species diversity occurring in the southern temperate (New Zealand). Nematode species diversity however was similar for the northern and southern temperate (UK and New Zealand) and the tropical area (Trinidad and Tobago). Thus, although the number of locations studied was limited, these data do not conform to a gradient in species diversity with latitude as has been previously supposed. The success of ASUs to compare species diversities in standardised habitat units augurs well for their future use in other ecological areas such as biogeographical or pollution studies. (C) 2006 Elsevier B.V. All rights reserved.},
	keywords = {artificial substrata, benthic species diversity, latitudinal gradients, nematodes, polychaetes},
	doi = {DOI 10.1016/j.jembe.2005.12.030},
	author = {Gobin, JF and Warwick, R. M.}
}
