R. S. K. Barnes

Coastal Lagoons. The Natural History of a Neglected Habitat.

Preface Acknowledgements 1. Introduction 2. Formation and fate of lagoons 3. The lagoonal environment 4. Lagoonal ecology 5. Strategies for lagoonal species 6. Human use of lagoons 7. Methods for the study of coastal lagoons 8. Other coastal lagoon-like systems Further reading References Indexes.

Fundamentals of aquatic ecology

Contributors. Preface. Part 1: Introduction. 1. Organisms and Ecosystems (K.H. Mann). Part 2: Aquatic Ecosystems. 2. Ecology of Water columns (I . Valiela). 3. Ecology of Coastal Ecosystems (I. Valiela). 4. Ecology of Deep--Water Zones (B.T. Hargrave). 5. Lakes and Oceans as Functional Who9les (D.W. Schindler). 6. Aquatic Ecosystems and Global Ecology (D.W. Schindler). Part 3: Aquatic Individuals and Communities. 7. Community Organization in Marine and Freshwater Environments (C.R. Townsend). 8. Reproduction, Life Histories and Dispersal, (R.S.K. Barnes). 9. Speciation and Biogeography. (J.H.R. Gee). 10. Specialist Aquatic Feeding Mechanism (J.H.R. Gee). Part 4: Habitat Types Peculiar to Aquatic Systems. 11. Reefs (R.N. Hughes). 12. Streams and Rivers: One--Way Flow Systems (M.J. Winterbourn and C.R. Townsend). Part 5: Human Effects. 13. Impacts of Mana s Activities on Aquatic Systems (B.T. Hargrave). Index.

What, if anything, is a brackish-water fauna?

The nature of the fauna of brackish-water environments is reviewed. It is concluded that: (a) a specific brackish-water macrofauna does not exist; (b) in salinities of > c . 5-8‰ the fauna is one that also occurs in soft sediments under fully marine conditions when circumstances (possibly the absence of competing species) permit; (c) in salinities of c . 5‰ the fauna is essentially a freshwater one; and (d) inability to cope physiologically with brackish water is not a factor of major importance in limiting species diversity in these habitats, except in the vicinity of 5‰ salinity. Caution is therefore advised in assigning brackish status to past environments on the basis of their preserved fauna.

The coastal lagoons of Britain: An overview and conservation appraisal

Abstract Britain possesses a total of 41 remaining coastal lagoon sites, many former lagoons having disappeared as a result of natural causes (including evolution into freshwater lakes) and human interference. All British lagoons are isolated behind barriers of shingle (with or without admixture of sand) and most received sea-water influx only by percolation through, or occasional overtopping of, this shingle. As such, they are of unusual ‘North Atlantic’ physiographic types from a global viewpoint. Their macrofaunal species richness varies with lagoonal salinity and area (although these account for only 21% of the variation), whilst the number of specialist lagoonal species within any given system is directly related to total species richness. A comparative site assessment, leading to identification of the nationally most important lagoonal systems, is described.

The faunas of land-locked lagoons: Chance differences and the problems of dispersal

Abstract The species richnesses and faunal similarities of a series of 24 land-locked, brackish coastal lagoons in East Anglia, U.K., are analyzed with regard to potential causal factors. Variation in species richness cannot be explained by such parameters as hydrological regime, substratum, age or area; only salinity and isolation have significant effects although they account for less than 20% of the total variation. The two faunal-similarity tests used gave different results, but such relatively few, statistically significant faunal similarities as are displayed on either basis are not related to habitat similarity in terms of hydrography, sediment type, area or usage by coastal birds (the latter casting doubt on the role of birds as major agents of dispersal); only salinity consistently exerted a significant effect, although geographical proximity and age were each significant on one of the two tests. Apart from the effect of salinity (which is not surprising because the lagoons range from 1 to more than 30‰), it is concluded that the depauperate lagoonal faunas are largely chance assemblages resulting from the vagaries of colonization patterns. Dispersal from lagoon to lagoon probably was effected mainly during periods of coastal seawater flooding but, if this is so, the supply of colonists has now been cut off by recent coastal defence works.

Regional and latitudinal variation in the diversity, dominance and abundance of microphagous microgastropods and other benthos in intertidal beds of dwarf eelgrass, Nanozostera spp.

The smaller macroscopic members of the epifauna and shallowly-burrowing infauna of comparable intertidal beds of dwarf eelgrass and associated areas of non-vegetated sediment were investigated with uniform methodology in the cool-temperate English southern North Sea (Nanozostera noltii), warm-temperate southern coast of the Western Cape, South Africa (N. capensis) and in subtropical southern Queensland, Australia (N. muelleri capricorni), together with equivalent seagrass sites in tropical Sulawesi, Indonesia, and Seychelles, Western Indian Ocean. Epifaunal microphagous microgastropods dominated both the eelgrass and non-vegetated cool- and warm-temperate sites with >80% of macrofaunal individuals, but decreased markedly in density and dominance with decreasing latitude, down to near zero in the tropics; microgastropod species diversity in the Nanozostera increased with decreasing latitude, whilst their species richness per core sample was highest in the warm temperate zone. Other co-existing—largely infaunal—taxa (mainly annelid worms, bivalve molluscs and crabs), however, showed less marked latitudinal variation in density and no relationship of taxon diversity with latitude. With few exceptional cases, microgastropod density, dominance, species richness and diversity were greater in the eelgrass beds than in adjacent non-vegetated sediments, as were the densities and taxon diversities of the associated faunal groups, although within the beds themselves there were no significant correlations between seagrass density and the density or diversity of either the microgastropods or their associated fauna. The extent to which the presence or absence of seagrass influenced the underlying community composition of the benthic fauna varied between localities. These results are consonant with an increasing effect of predation in low latitudes on small epifauna.

The diversity of living organisms

List of Contributors Preface. Introduction. PART I: SUPERKINGDOM PROKARYA. 1. Kingdom Bacteria (M.J. Chapman, L. Margulis, D. Sagan) PART II: SUPERKINGDOM EUKARYA. 2. Kingdom Protoctista (M.J. Chapman, L. Margulis, D. Sagan) 3. Kingdom Fungi (K.A. Pirozynski) 4. Kingdom Plantae (A. Hemsley) 5. Kingdom Animalia (R.S.K. Barnes) 6. Further Sources of Information Index to Groups of Organisms.

Interference competition in the intertidal mud snail Hydrobia ulvae : egestion rates revisited

Egestion in the intertidal mud snail Hydrobia ulvae was investigated under conditions in which coprophagy did not occur, both in laboratory populations (comprising 11 experimental densities from 1000 to 120,000 ind m -2 ) and in a field population with an average density of 50,000 ind m -2 (24 test densities spanning the local range of 120,000 ind m -2 ). In contrast to an earlier study that suggested marked reduction in egestion rate in H. ventrosa as a consequence of interference competition, no such effect occurred in the natural population of H. ulvae, or in the experimental populations except at densities of at least 100,000 ind m -2 . Neither did any significant increase in inactivity or movement off the experimental substrata occur with increasing density. These results are discussed in relation to resource limitation in natural densities of mud snails.

Animal abundance and food availability in coastal lagoons and intertidal marine sediments

The relationships between the standing stocks of deposit-feeding benthic invertebrates and benthic chlorophyll- a , phaeopigment and total combustible organic matter were investigated at a series of coastal lagoons and in the type of intertidal soft-sediment sites from which the lagoons originated. Across all the sites, in Norfolk, UK, an inverse relationship occurred between (a) the amounts of chlorophyll -a and of other potential food materials and (b) the degree of coverage by water. The biomass of consumers also decreased with increased water coverage, so that the lagoons supported less biomass than the adjacent high-level intertidal sites. Further, the deposit-feeder biomass supported by unit food decreased with extent of water coverage. There was no evidence of any relationship between deposit-feeder and food biomass within any single site, in spite of the study period being selected to be that in which there was maximum likelihood of competition for microphytobenthic food. Whilst chlorophyll concentrations may set the maximum achievable level of consumer biomass at these sites, including in the deeper lagoons setting very low potential maximum population densities, the seasonal abundance patterns of the deposit feeders appear to be determined by other factor(s).

Relative carapace and chela Proportions in some Ocypodid crabs (Brachyura, Ocypodidae)

[Die Veranderungen von 4 relativen Carapax- und Chela-Masen bei zunehmender Grose wurden an 13 species der genera Macrophthalmus, Australoplax, Cleistostoma und Paracleistostoma aus Australasien beschrieben. Die Schlusfolgerung wird gezogen, das die bisherige Praxis der Einbeziehung einzelner Werte von relativen Grosenverhaltnissen bei der Beschreibung von Arten der Macrophthalminae ohne Bezug auf die Veranderung wahrend der Entwickelung nur geringe oder gar keine Gultigkeit hat., Die Veranderungen von 4 relativen Carapax- und Chela-Masen bei zunehmender Grose wurden an 13 species der genera Macrophthalmus, Australoplax, Cleistostoma und Paracleistostoma aus Australasien beschrieben. Die Schlusfolgerung wird gezogen, das die bisherige Praxis der Einbeziehung einzelner Werte von relativen Grosenverhaltnissen bei der Beschreibung von Arten der Macrophthalminae ohne Bezug auf die Veranderung wahrend der Entwickelung nur geringe oder gar keine Gultigkeit hat.]