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- Influence of disturbance and nutrient enrichment on early successional fouling communities in an oligotrophic marine systemPublication . Canning-Clode, João; Kaufmann, Manfred; Molis, Markus; Wahl, Martin; Lenz, MarkDisturbance and productivity are often cited as the main factors determining temporal and spatial patterns in species distribution and the diversity of com munities. A field experiment was conducted to test the role of these factors in the structuring of early successional fouling communities in a nutrient limited system at the south coast of Madeira Island. Macro-benthic sessile communi ties, established on artificial settlement substrata, were manipulated and sur veyed over a 9-week period. We applied mechanical disturbances of four different frequencies crossed with three levels of inorganic nutrient enrichment. Fertilization enhanced community diversity by favouring the establishment and growth of macroalgae. Disturbance reduced diversity by eliminating species – but only at the highest nutrient level. This is explained by a multiple-stressor model; species most sensitive to nutrient deficiency (only present in the highest enrichment treatment) were simultaneously the most sensitive to disturbance.
- First report of Ciguatoxins in two starfish species: Ophidiaster ophidianus and Marthasterias glacialisPublication . Silva, Marisa; Rodriguez, Inés; Barreiro, Aldo; Kaufmann, Manfred Josef; Neto, Ana Isabel; Hassouani, Meryem; Sabour, Brahim; Alfonso, Amparo; Botana, Luis M.; Vasconcelos, VitorCiguatera fish poisoning (CFP) is a syndrome caused by the ingestion of fish contaminated with Ciguatoxins (CTXs). These phycotoxins are produced mainly by dinoflagellates that belong to the genus Gambierdiscus that are transformed in more toxic forms in predatory fish guts, and are more present in the Indo-Pacific and Caribbean areas. It is estimated that CFP causes per year more than 10,000 intoxications worldwide. With the rise of water temperature and anthropogenic intervention, it is important to study the prevalence of CFP in more temperate waters. Through inter- and subtidal sampling, 22 species of organisms were collected, in Madeira and Azores archipelagos and in the northwestern Moroccan coast, during September of 2012 and June and July of 2013. A total of 94 samples of 22 different species of bivalves, gastropods, echinoderms and crustaceans where analyzed by Ultra Performance Liquid Chromatography-Mass Spectometry-Ion Trap-Time of Flight (UPLC-MS-IT-TOF) and Ultra Performance Chromatography- Mass Spectrometry (UPLC-MS). Our main aim was to detect new vectors and ascertain if there were some geographical differences. We detected for the first time putative CTXs in echinoderms, in two starfish species—M. glacialis and O. ophidianus. We detected differences regarding uptake values by organisms and geographical location. Toxin amounts were significant, showing the importance and the need for continuity of these studies to gain more knowledge about the prevalence of these toxins, in order to better access human health risk. In addition, we suggest monitoring of these toxins should be extended to other vectors, starfish being a good alternative for protecting and accessing human health risk.
- Daytime dive characteristics from six short-finned pilot whales Globicephala macrorhynchus off Madeira IslandPublication . Alves, Filipe; Dinis, A.; Ribeiro, C.; Nicolau, C.; Kaufmann, M.; Fortuna, C. M.; Freitas, L.
- Local benthic assemblages in shallow rocky reefs find refuge in a marine protected area at Madeira IslandPublication . Alves, Filipe; Canning-Clode, João; Ribeiro, Cláudia; Gestoso, Ignacio; Kaufmann, ManfredThe patterns of variability in the composition and structure of benthic communities along two depth strata (5 and 10 m) and the presence of sea urchins in structuring the subtidal rocky reefs were quantified in a long-established coastal marine protected area (Garajau MPA) and in two size equivalent and contiguous impacted areas (one highly urbanized and other with high fishing pressure) at Madeira Island (northeast Atlantic). Results suggest i) the MPA could be acting as a refuge for local biodiversity, ii) communities from the highly fished area could be suffering an impoverishment of local biodiversity, and iii) communities from the highly urbanized area would be enriched by the establishment of opportunistic species. These findings support that the level of human-pressure likely plays an important role in the composition of benthic communities in this insular ecosystem, although this was more relevant at the shallower stratum where the key grazer Diadema africanum explained 65% of the variance of benthic assemblages. It is suggested that this MPA small dimension and proximity to human impacted areas are limiting the survival of predators of the D. africanum.
- New invertebrate vectors of Okadaic acid from the North Atlantic Waters - Portugal (Azores and Madeira) and MoroccoPublication . Silva, Marisa; Rodriguez, Inés; Barreiro, Aldo; Kaufmann, Manfred Josef; Neto, Ana Isabel; Hassouani, Meryem; Sabour, Brahim; Alfonso, Amparo; Botana, Luis M.; Vasconcelos, VitorOkadaic acid and its analogues are potent phosphatase inhibitors that cause Diarrheic Shellfish Poisoning (DSP) through the ingestion of contaminated shellfish by humans. This group of toxins is transmitted worldwide but the number of poisoning incidents has declined over the last 20 years due to legislation and monitoring programs that were implemented for bivalves. In the summer of 2012 and 2013, we collected a total of 101 samples of 22 different species that were made up of benthic and subtidal organisms such echinoderms, crustaceans, bivalves and gastropods from Madeira, São Miguel Island (Azores archipelago) and the northwestern coast of Morocco. The samples were analyzed by UPLC-MS/MS. Our main objective was to detect new vectors for these biotoxins. We can report nine new vectors for these toxins in the North Atlantic: Astropecten aranciacus, Arbacia lixula, Echinaster sepositus, Holothuria sanctori, Ophidiaster ophidianus, Onchidella celtica, Aplysia depilans, Patella spp., and Stramonita haemostoma. Differences in toxin contents among the species were found. Even though low concentrations were detected, the levels of toxins that were present, especially in edible species, indicate the importance of these types of studies. Routine monitoring should be extended to comprise a wider number of vectors other than for bivalves of okadaic acid and its analogues.