Inexpensive Video Drop-camera for Surveying Sensitive Benthic Habitats: Applications from Glass Sponge (Hexactinellida) Reefs in Howe Sound, British Columbia

Where marine waters are shallow and bathymetric features are steep, the typically employed multi-beam side scan sonar is not always reliable for identifying complex biological structures. Here, we present a cost-efficient method used in Howe Sound, British Columbia, for bathymetric mapping, exploration, and ground-truthing of glass sponge bioherms. A simple depth sounder and software package was used to produce bathymetric maps. From these maps, prospective sites were selected and surveyed to investigate bioherm presence with a simple drop-camera towed off the bow of a small drifting vessel during calm seas. This method was used during a 4-year citizen science initiative that led to the discovery of 12 glass sponge bioherms in Howe Sound, the first step in protecting these globally unique reefs from the impact of bottom-contact fishing, anchoring, and potential industrial contamination. Before our work using this method, only two glass sponge bioherms had been identified in Howe Sound. The method also proved effective as a means to quantify damage to bioherms from fishing gear.

Micropalaeontology of the Permian Marls of Merbah el Oussif (Jebel Tebaga, Tunisia) with special emphasis on the Ostracods

The Marls of Merbah el Oussif are part of the Permian series of the Jebel Tebaga of Médénine in Tunisia. They belong to the uppermost Murghabian, a stage intermediate between the Wordian and the Capitanian. These green marls were deposited in lows at the base of sponge bioherms. The sedimentation rate was high and the environment well oxygenated. The marls contain a relatively rich assemblage of isolated sponges, gastropods, smaller foraminifera, fusulinids, dasycladacean algae and ostracods. Amongst those, for the first time reported from the Permian of Tunisia, 14 species have been identified and one new species described, Bairdiacypris postrectiformis sp. nov. The geographic and stratigraphic distribution of several species are discussed. This ostracod fauna indicates a shallow nearshore environment and suggests a western, not eastern connection between the Tethys and the Texas Sea.

Etude geochimique d'une sequence des 'terres noires'; application au probleme de l'ecologie de spongiaires constructeurs

The 'black earths' of Diois (French Prealps) and the Laragne region are a monotonous succession of argillaceous and marly beds of late Bajocian to early Oxfordian age. They contain platy limestones and associated lentils of abundant sponge spicules, apparently bioherms, especially near the middle of the sequence. Variable but high sulfur content, constant high boron content, and constant contents of Cr, V, Ba, Sr, and Ga in these rocks indicate euxinic conditions of deposition. The platy limestones represent influxes of colder, more oxygenated water, brought into the deep part of the basin by intermittent currents, making possible the development of the sponge bioherms under semi-euxinic conditions.