Environmental impact and recovery at two dumping sites for dredged material in the North Sea.

The environmental impact and recovery associated with the long and uninterrupted disposal of large volumes of moderately contaminated dredged material from the port of Rotterdam was studied at nearby dumping sites in the North Sea. Observations were made on sediment contamination, ecotoxicity, biomarker responses and benthic community changes shortly after dumping at the 'North' site had ceased and at the start of disposal at the new dumping site 'Northwest'. During the period of dumping, very few benthic invertebrates were found at the North site. Concentrations of cadmium, mercury, polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs) and tributyltin (TBT) in the fine sediment fraction (<63 microm) from this site were 2-3 times higher than at the reference site. In four different bioassays with marine invertebrates the sediments showed no acute toxic effects. In tissue (pyloric caeca) of resident starfish Asterias rubens, residual levels of mercury, zinc, PCBs and dioxin-like activity were never more than twice those at the reference site. Four different biomarkers (DNA integrity, cytochrome P450 content, benzo[a]pyrene hydroxylase activity and acetylcholinesterase inhibition) were used on the starfish tissues, but no significant differences were found between North and the reference site. Minor pathological effects were observed in resident dab Limanda limanda. One year after dumping had ceased at the North site, a significant increase in the species richness and abundance of benthic invertebrates and a concomitant decrease in the fine sediment fraction of the seabed were observed. After 8.2 million m3 of moderately contaminated dredged material had been dumped at the new dumping site Northwest, the species richness and abundance of benthic invertebrates declined over an area extending about 1-2 km eastwards. This correlated with a shift in sediment texture from sand to silt. The contamination of the fine sediment fraction at the Northwest location doubled. It is concluded that marine benthic resources at and around the dumping sites have been adversely affected by physical disturbance (burial, smothering). However, no causal link could be established with sediment-associated contaminants from the dredged spoils.

Cellular location of (2R, 3R, 7Z)-2-aminotetradec-7-ene-1, 3-diol, a potent antimicrobial metabolite produced by the Caribbean sponge Haliclona vansoesti.

The Caribbean sponge Haliclona vansoesti has been found to contain large amounts of a new sphingosine derivative, (2R, 3R, 7Z)-2-aminotetradec-7-ene-1, 3-diol (compound 1). To determine the localization of this compound within the organism, cell distribution and quantitative determination of the aminodiol content of cell fractions obtained by differential centrifugation have been performed. Results show that choanocytes and archaeocytes are the major sponge cell types and that H. vansoesti harbour small photosynthetic symbionts (cyanobacteria) and few heterotrophic bacteria. Reverse-phase HPLC analyses of the cell fractions reveal that the aminodiol 1 is not associated with the prokaryotic endobionts but with the sponge cells, in particular the archaeocytes. This is clearly established by the positive significant correlation existing between the numbers of archaeocytes and the amounts of aminodiol 1. The mean aminodiol concentration is estimated to be 2 microg/10(5) archaeocytes. The aminodiol 1 is also found in substantial amounts in primary cell cultures, so that cell culture can be envisaged as an option for its production. Sponge cell suspensions display potent antibacterial and antiyeast activities, in correlation with their aminodiol content, indicating that this compound is at least in part responsible for these activities in the sponge. The release of the aminodiol I into the external medium suggests that this substance may be involved in the defence mechanisms of the sponge.

(2R,3R,7Z)-2-Aminotetradec-7-ene-1,3-diol, a new amino alcohol from the caribbean sponge Haliclona vansoesti.

The Caribbean marine sponge Haliclona vansoesti was found to contain a high amount (5% dry wt) of a new analogue of 4-sphingenine, (2R,3R, 7Z)-2-aminotetradec-7-ene-1,3-diol (1). Its structure was determined by detailed spectroscopic analysis. The relative configuration was deduced from the NMR data of the corresponding acetonide 5, while the absolute configuration was secured via protection of the primary alcohol and amino groups, and esterification of the secondary alcohol with Mosher's reagent.

New sesquiterpene/quinones from two sponges of the genus Hyrtios.

Two sponges of the genus Hyrtios have been found to contain new sesquiterpene/quinones identified by detailed spectroscopic analysis. Four new compounds with a 4,9-friedodrim-3-ene skeleton [hyrtiophenol (2), 5-epihyrtiophenol (3), 18-hydroxy-5-epihyrtiophenol (4), and 18-hydroxyhyrtiophenol (5)] were isolated from Hyrtios sp. (Seychelles Islands) along with isospongiaquinone (1). Moreover, the new compound 21-hydroxy-19-methoxyarenarone (8), which bears the 4, 9-friedodrim-4(15)-ene skeleton, was isolated from Hyrtios tubulatus (Curaçao) along with arenarol (6) and 5-epiilimaquinone (7). Assignment of the (13)C NMR signals of four types of 4, 9-friedodrimene skeletons found in sponges is presented.