Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) have recently been identified in fish and wildlife from the Baltic Sea. Both OH-PBDEs and MeO-PBDEs are known natural products, while OH-PBDEs also may be metabolites of PBDEs. The aim of the present study was to determine if the red macroalga Ceramium tenuicorne could be a source for MeO- and OH-PBDEs in the Baltic environment. Blue mussels (Mytilus edulis) from the same area were also investigated for their content of MeO- and OH-PBDEs. Seven OH-PBDEs and four MeO-PBDEs were present both in the red macroalga and the blue mussels. The mussels also contained a monochlorinated OH-tetraBDE. One of the compounds, 6-methoxy-2,2',3,4,4',5-hexabromodiphenyl ether, has never been reported to occur in the environment. The identification was based on comparison of relative retention times with reference standards, on two gas chromatographic columns of different polarities, together with comparisons of full-scan electron capture negative ionization (ECNI) and electron ionization (EI) mass spectra. It is shown that MeO-PBDEs and OH-PBDEs are present in algae, but at this stage it could not be confirmed if the compounds are produced by the alga itself or by its associated microflora and/or microfauna.

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Mathematical and experimental simulations predict that external fertilization is unsuccessful in habitats characterized by high water motion. A key assumption of such predictions is that gametes are released in hydrodynamic regimes that quickly dilute gametes. We used fucoid seaweeds to examine whether marine organisms in intertidal and subtidal habitats might achieve high levels of fertilization by restricting their release of gametes to calm intervals. Fucus Marine organisms with external fertilization must achieve high probabilities of gamete encounters in an environment that may rapidly dilute gametes in three dimensions. The most important ecological conditions for successful external fertilization are synchrony of gamete release, proximity of individuals, and low water motion (1-8). Synchronous release of gametes has evolved in many marine organisms (e.g., refs. 9 and 10); however, even if release occurs synchronously and from aggregated individuals, a large number of potential recruits could be lost due to the effects of gamete dilution if spawning coincides with high water motion. Experimental field studies (1, 5) show that commonly observed water velocities dilute gametes close to their source, leading to the fertilization of only a small proportion of eggs; in addition, theoretical models (11, 12) predict that fertilization success in turbulent flows may be lower than 1%. An important exception maybe surge channels, where turbulent mixing occurs, but exchange with the adjacent water body is low, thereby reducing dilution of gametes (13). But under such turbulent conditions shear forces still limit fertilization success (14). However, the widespread occurrence of polyspermy blocks (15) and reproductive pheromones (16-18) in organisms living in intertidal and subtidal habitats suggests that fertilization may often occur under calmer conditions than those that usually prevail in these habitats because polyspermy blocks are required when eggs are likely to encounter high densities of sperm at fertilization and pheromones are effective at short range (micrometers to millimeters). Quantitative data on fertilization success during natural events of gamete release show that during periods when the majority of gametes are released, an average of 70-100% of the eggs are fertilized in organisms as diverse as fucoid algae (19), echinoderms (4,7,20,21), and fish (refs. 22 and 23; but also see ref. 24). Whether these high levels of fertilization are widely representative is unknown, although a few observations of simultaneous spawning by many species during slack tides (25, 26) and selection of spawning locations and periods (23) suggest that organisms might regulate reproductive behavior to avoid suffering the reduced fertilization success due to high water motion that modeling and experimental field studies have predicted.Fucoid algae dominate the biomass on many intertidal rocky shores in temperate regions, and in the atidal Baltic Sea the dioecious species Fucus vesiculosus L. is the only widely dist...

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Background: Theory predicts that speciation can be quite rapid. Previous examples comprise a wide range of organisms such as sockeye salmon, polyploid hybrid plants, fruit flies and cichlid fishes. However, few studies have shown natural examples of rapid evolution giving rise to new species in marine environments.