A new threat to local marine biodiversity: filamentous mats proliferating at mesophotic depths off Rapa Nui

Mesophotic and deeper habitats (∼40 to 350 m in depth) around Rapa Nui (Easter Island) were investigated using a remotely operated vehicle. We observed extensive fields of filamentous cyanobacteria-like mats covering sandy substrates and mostly dead mesophotic Leptoseris spp. reefs. These mats covered up to 100% of the seafloor off Hanga Roa, the main village on the island, located on its western side. The highest mortality of corals was observed at depths between 70 and 95 m in this area. Healthy Leptoseris reefs were documented off the northern and southeastern sides of the island, which are also the least populated. A preliminary morphologic analysis of samples of the mats indicated that the assemblage is composed of at least four filamentous taxa, including two cyanobacteria (cf. Lyngbya sp. and Pseudoanabaena sp.), a brown alga (Ectocarpus sp.), and a green alga (Cladophora sp.). An ongoing eutrophication process is suggested as a potential driver of the proliferation of these filamentous mats off Hanga Roa village.

Interference of fixatives and fixation period on the morphologic analysis of ovarian preantral follicles

Summary Ovine ovarian fragments (3 × 3 × 1 mm) were fixed in neutral buffered formalin (NBF), Carnoy’s solution (CAR), Davidson’s solution (DAV), or paraformaldehyde (PFA) for 12 h or 24 h. After this fixation time, each fragment was prepared for histological analysis. Although fixative and fixation period did not affect follicular and stromal cells density, the percentages of morphologically normal primordial and primary follicles was affected by the fixative type and period of fixation. Paraformaldehyde was not indicated as a fixative for ovarian fragments. Formalin was a suitable fixative only when the period of fixation was 12 h, while Carnoy was efficient after a fixation period of 24 h. In conclusion, the most indicated fixative for the morphological evaluation of ovarian preantral follicles was DAV, regardless of the fixation period, that is 12 or 24 h.

Plastic toy soldiers, a lost battle? – an analytical perspective

The conservation and preservation of museum collections requires a detailed understanding of their constituent materials which are often natural, synthetic or semi-synthetic polymers. The use of a wide variety of instrumental techniques can give an extraordinary amount of quality information, by delivering complementary data regarding composition and structure. This study was triggered by the Oporto Military Museum (Museu Militar do Porto) conservators who observed that a set of plastic toy soldiers dating back to the middle of the 20th century from the museum exhibition started to present severe and accelerated degradation process. With this is mind, the authors envisaged a methodology for the characterisation of these soldier toys that compromised elemental, structural and morphologic analysis, to allow the identification of polymers, their additives, and the degradation products. The methodology comprised stereoscopic microscopy and VP-SEM-EDS to recognize the micromorphology, ATR-FTIR to identify the polymer, 1H and 13C NMR to identify their additives, and micro-XRD to identify degradation products with a crystal structure. With this complementary analytical approach the composition of the toy soldiers was identified as being made of cellulose acetate plastic with triphenyl phosphate and dimethyl phthalate as major additives, and crystallyne efflorescence of triphenyl phosphate were identified as a degradation product. This methodology shows to be very adequate for a detailed characterization of plastic artefacts in museum environments.