The frequency of marine sponges that harbour photosynthetic organisms was examined in a tropical area of the Western Indian Ocean. Out of 77 species from five different habitats in Zanzibar, 55 (71.5%) were found to have photosynthetic activity, as assayed by in situ pulse amplitude modulated (PAM) fluorometry (and validated by measurements of chlorophyll content). A significantly higher percen...

Predators can affect the vertical distribution of mobile intertidal invertebrates in two ways: they can (1) cause greater mortality of prey at certain intertidal levels, and (2) induce prey to seek safer intertidal areas. In this study, we investigate whether low-intertidal and subtidal predators affect the intertidal distribution of two congeneric species of small herbivorous gastropods of nor...

Intertidal sediment distribution is an important factor in the understanding of estuarine ecological, morphological and pollution processes.Airborne remote sensing is identiŽ ed as a cost-eŒective tool that may be used to provide accurate synoptic maps of estuarine sediment distributions.However, prior to the collection and analysis of airborne imagery, spectral characterization of intertidal s...

Many eurythermal organisms alter composition of their membranes to counter perturbing effects of environmental temperature variation on membrane fluidity, a process known as homeoviscous adaptation. Marine intertidal gastropods experience uniquely large thermal excursions that challenge the functional integrity of their membranes on tidal and seasonal timescales. This study measured and compare...

1 The marine intertidal is one of the harshest environments on earth. Organisms inhabiting the transition from land to sea are subject to a host of environmental stresses, including temperature variation, dessication stress, wave force, and salinity [1, 2]. The daily tidal cycle is largely responsible for the drastic, rapid temperature fluctuations typical of the intertidal, exposing organisms ...

Stable isotope analysis was used to determine the relative proportions of terrestrial and marine subsidies of carbon to invertebrates along a tidal gradient (low-intertidal, mid-intertidal, high-intertidal, supralittoral) and to determine the relative importance of terrestrial carbon in food web pathways leading to chum salmon fry Oncorhynchus keta (Walbaum) in Howe Sound, British Columbia. We ...

This paper examines how the use of various taxonomic levels and morphological functional groups influences the interpretation of multivariate analyses when comparing macroalgal assemblages in different regions in the Northeast Pacific. We found that for intertidal assemblages, within-site variation was high at the species level and regions only became discernable from the genus level to the ord...

The Point Conception, California, USA region (hereafter PC) is one of the most important biogeographic and oceanographic discontinuities on the US west coast. Here we address how mesoscale oceanographic variability in the region around PC affects the growth of the competitively dominant species in the rocky intertidal assemblage: the mussel Mytilus californianus. Strong upwelling and high wave ...

On wave-sheltered shores of the northeastern Pacific, the population size structure of Littorina sitkana varies with intertidal height, as larger snails are mostly found only in the upper intertidal. This pattern has been attributed to high predation rates by crabs (and perhaps fish) on large snails inhabiting low-intertidal areas; i.e., large snails are presumed to be rare there simply because...

Rocky shores are one of the most important habitats of marine environment in coastal areas. This study was done in 2010-2011 to investigate the diversity of true crabs in intertidal rocky shores of Qeshm island. Samples were collected from intertidal zones during the low-tide at 5 stations. The specimens were fixed in 70% Etanol and transferred to laboratory for identification. Altogether, 15 c...