Longer and less overlapping food webs in anthropogenically disturbed marine ecosystems: confirmations from the past

The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs.

Synthesis and structure - Activity relationship study of potent cytotoxic analogues of the marine alkaloid Lamellarin D

The marine alkaloid, Lamellarin D (Lam-D), has shown potent cytotoxicity in numerous cancer cell lines, and was recently identified as a potent topoisomerase I inhibitor. A library of open lactone analogs of Lam-D was prepared from a methyl 5,6-dihydropyrrolo[2,1-a]isoquinoline-3- carboxylate scaffold (1) by introducing various aryl groups through sequential and regioselective bromination, followed by Pd(0)-catalyzed Suzuki cross-coupling chemistry. The compounds were obtained in a 24-44% overall yield, and tested in a panel of three human tumor cell lines, MDA-MB- 231 (breast), A-549 (lung), and HT-29 (colon), to evaluate their cytotoxic potential. From these data the SAR study concluded that more than 75% of the open-chain Lam-D analogs tested showed cytotoxicity in a low micromolar GI50 range.

Synthesis and structure - Activity relationship study of potent cytotoxic analogues of the marine alkaloid Lamellarin D

The marine alkaloid, Lamellarin D (Lam-D), has shown potent cytotoxicity in numerous cancer cell lines, and was recently identified as a potent topoisomerase I inhibitor. A library of open lactone analogs of Lam-D was prepared from a methyl 5,6-dihydropyrrolo[2,1-a]isoquinoline-3- carboxylate scaffold (1) by introducing various aryl groups through sequential and regioselective bromination, followed by Pd(0)-catalyzed Suzuki cross-coupling chemistry. The compounds were obtained in a 24-44% overall yield, and tested in a panel of three human tumor cell lines, MDA-MB- 231 (breast), A-549 (lung), and HT-29 (colon), to evaluate their cytotoxic potential. From these data the SAR study concluded that more than 75% of the open-chain Lam-D analogs tested showed cytotoxicity in a low micromolar GI50 range.

Calcium phosphate biomaterials from marine algae. Hydrothermal synthesis and characterisation

Calcium phosphate compounds such as Hydroxyapatite (HAp) were prepared by hydrothermal synthesis with phycogenic CaCO3 as starting material. Material obtained was characterised by usual methods (XRD, FTIR, TG, N2-adsorption, SEM and EDX) in order to study its physical-chemical characteristics. The prepared HAp showed that it may be suitable for use as a biomaterial.

Geographic patterns of genetic variation in a broadly distributed marine vertebrate: new insights into loggerhead turtle stock structure from expanded mitochondrial DNA sequences

Previous genetic studies have demonstrated that natal homing shapes the stock structure of marine turtle nesting populations. However, widespread sharing of common haplotypes based on short segments of the mitochondrial control region often limits resolution of the demographic connectivity of populations. Recent studies employing longer control region sequences to resolve haplotype sharing have focused on regional assessments of genetic structure and phylogeography. Here we synthesize available control region sequences for loggerhead turtles from the Mediterranean Sea, Atlantic, and western Indian Ocean basins. These data represent six of the nine globally significant regional management units (RMUs) for the species and include novel sequence data from Brazil, Cape Verde, South Africa and Oman. Genetic tests of differentiation among 42 rookeries represented by short sequences (380 bp haplotypes from 3,486 samples) and 40 rookeries represented by long sequences (~800 bp haplotypes from 3,434 samples) supported the distinction of the six RMUs analyzed as well as recognition of at least 18 demographically independent management units (MUs) with respect to female natal homing. A total of 59 haplotypes were resolved. These haplotypes belonged to two highly divergent global lineages, with haplogroup I represented primarily by CC-A1, CC-A4, and CC-A11 variants and haplogroup II represented by CC-A2 and derived variants. Geographic distribution patterns of haplogroup II haplotypes and the nested position of CC-A11.6 from Oman among the Atlantic haplotypes invoke recent colonization of the Indian Ocean from the Atlantic for both global lineages. The haplotypes we confirmed for western Indian Ocean RMUs allow reinterpretation of previous mixed stock analysis and further suggest that contemporary migratory connectivity between the Indian and Atlantic Oceans occurs on a broader scale than previously hypothesized. This study represents a valuable model for conducting comprehensive international cooperative data management and research in marine ecology.

Effects of artisanal fisheries on the scorpaenids (Scorpaena spp.) reproduction in the marine protected area of Cap de Creus (NW Mediterranean)

Rockfish species are considered important to the ecology of rocky-reef communities which constitute a key habitat in many coastal marine protected areas (MPAs). These species, which are commercially valuable for artisanal fisheries in the Mediterranean, display particular biological traits that could render them vulnerable to fishing. In this study we monitored the artisanal fisheries of scorpaenids (Scorpaena spp.) in the MPA of Cap de Creus (northwestern Mediterranean) in order to estimate the status of their populations, to link captures with the reproduction of these species, and to evaluate the potential impact that artisanal fishing may have on them. Data from onboard sampling with artisanal fishermen and from fisheries statistics (total landings) were used. Total landings and catch per unit of effort (CPUE) follow a clearly seasonal cycle, with a prominent peak during the summer months coinciding with their spawning season, which may be due to mating behavior prior to fertilization. Although maximum sizes are bigger inside the MPA than in non-protected areas situated close by, a significant percentage of individuals caught inside the MPA are below their size at sexual maturity. Although rockfish seem to be favored by the partial protection of the MPA, the allowed artisanal fisheries are probably impacting the reproduction of these species

A multi-screening approach for marine-derived fungal metabolites and the isolation of cyclodepsipeptides from Beauveria felina

Extracts obtained from 57 marine-derived fungal strains were analyzed by HPLC-PDA, TLC and ¹H NMR. The analyses showed that the growth conditions affected the chemical profile of crude extracts. Furthermore, the majority of fungal strains which produced either bioactive of chemically distinctive crude extracts have been isolated from sediments or marine algae. The chemical investigation of the antimycobacterial and cytotoxic crude extract obtained from two strains of the fungus Beauveria felina have yielded cyclodepsipeptides related to destruxins. The present approach constitutes a valuable tool for the selection of fungal strains that produce chemically interesting or biologically active secondary metabolites.

Validation of an analytical methodology for the quantitative analysis of petroleum hydrocarbons in marine sediment samples

This work describes a validation of an analytical procedure for the analysis of petroleum hydrocarbons in marine sediment samples. The proposed protocol is able to measure n-alkanes and polycyclic aromatic hydrocarbons (PAH) in samples at concentrations as low as 30 ng/g, with a precision better than 15% for most of analytes. The extraction efficiency of fortified sediments varied from 65.1 to 105.6% and 59.7 to 97.8%, for n-alkanes and PAH in the ranges: C16 - C32 and fluoranthene - benzo(a)pyrene, respectively. The analytical protocol was applied to determine petroleum hydrocarbons in sediments collected from a marine coastal zone.

The syntheses of the marine metabolites 3-bromoverongiaquinol and 5-monobromocavernicolin

An efficient synthesis of the marine metabolite 3-bromoverongiaquinol (1) and the first total synthesis of 5-monobromocavernicolin (2), both isolated from the marine sponge Aplysina cavernicola, have been described based on the 1,2 addition of the lithium enolate of N,O-bistrimethylsilylacetamide (BSA, 4) to 1,4-benzoquinone (3). Bromination and purification of the crude product on silica gel chromatography provided 3-bromoverongiaquinol (1) in 50% overall yield. Under alkaline conditions, the crude product of the bromination reaction was converted to 5-monobromocavernicolin (2) in 20% yield which was also obtained in 13% yield (25% yield based on recovered starting material) from 3-bromoverongiaquinol (1).

Antiparasitic bromotyrosine derivatives from the Caribbean marine sponge Aiolochroia crassa

Six bromotyrosine-derived compounds were isolated from the Caribbean marine sponge Aiolochroia crassa: 3-bromo-5-hydroxy-O-methyltyrosine (1), 3-bromo-N,N,N-trimethyltyrosinium (2), 3-bromo-N,N,N,O-tetramethyltyrosinium (3), 3,5-dibromo-N,N,N-trimethyltyrosinium (4), 3,5-dibromo-N,N,N,O-tetramethyltyrosinium (5), and aeroplysinin-1 (6). Structural determination was performed using NMR, MS and comparison with literature data. All isolated compounds were screened for their in vitro activity against Leishmania panamensis, Plasmodium falciparum and Trypanosoma cruzi. Compound 4 showed selective antiparasitic activity against Leishmania and Plasmodium parasites. This is the first report of compounds 1, 4 and 5 in the sponge A. crassa and the first biological activity reports for compounds 2-4. This work shows that bromotyrosines are potential antiparasitic agents.

Biomolecules produced in liquid-state fermentation by a marine-derived fungus, Penicillium roqueforti

Screening of biomass of a new marine-derived strain of Penicillium roqueforti, as produced by liquid-state fermentation, led to the identification of several volatile organic compounds active in the fatty acid pathway as well as fragments produced by their catabolism, terpenoids, and metabolites from the shikimic acid pathway. In addition, five non-volatile organic compounds, triolein, ergosterol peroxide, 9(11)-dehydroergosterol peroxide, 4-hydroxybenzaldehyde, and d-mannitol, were isolated and identified by spectroscopy. The results showed that this fungal strain did not produce any mycotoxin in the culture conditions applied, and thus is useful for industrial applications, where high value-added biomolecules are generated.

Design of marine generators for alternative diesel-electric power systems

This study compares different electric propulsion systems. Results of the analysis of all the advantages and disadvantages of the different propulsion systems are given. This thesis estimates possibilities to apply different diesel-electric propulsion concepts for different vessel types. Small and medium size vessel’s power ranges are studied. The optimal delivery system is chosen. This choice is made on the base of detailed study of the concepts, electrical equipment market and comparison of mass, volume and efficiency parameters. In this thesis three marine generators are designed. They are: salient pole synchronous generator and two permanent magnet synchronous generators. Their electrical, dimensional, cost and efficiency parameters are compared. To understand all the benefits diagrams with these parameters are prepared. Possible benefits and money savings are estimated. As the result the advantages, disadvantages and boundary conditions for the permanent magnet synchronous generator application in marine electric-power systems are found out.

Public-private partnership in marine litter waste management

Marine litter is an international environmental problem that causes considerable costs to coastal communities and the fishing industry. Several international and national treaties and regulations have provisions to marine litter and forbid disposal of waste into the sea. However, none of these regulations state a responsibility for public authorities to recover marine litter from the sea, like they do for marine litter that washes up on public beaches. In a financial evaluation of a value chain for marine litter incineration it was found out that the total costs of waste incineration are approximately 100 ─ 200 % higher than waste fees offered by waste contractors of ports. The high costs of incineration are derived from the high calorific value of marine litter and therefore a high incineration cost for the waste, and long distances between ports that are taking part in a project for marine litter recovery from the sea and an Energy-from-Waste (EfW) facility. This study provides a possible solution to diverting marine litter from landfills to more environmentally sustainable EfW use by using a public-private partnership (PPP) framework. PPP would seem to fit as a suitable cooperative approach for answering problems of current marine litter disposal in theory. In the end it is up to the potential partners of this proposed PPP to decide whether the benefits of cooperation justify the required efforts.

The Sedimentology, Ichnology and Hydrogeochemistry of the Late Miocene, Marginal Marine, Upper Pebas and Nauta Formations, Amazonian Foreland Basin, Peru

This thesis includes detailed sedimentological and ichnological studies on two geological units: the Pebas Formation, with a special focus in its informal upper member, and the Nauta Formation. Both formations were deposited during the Miocene in Northeastern Peruvian Amazonia, in the Amazon retroarc foreland basin. The Pebas and Nauta successions mainly consist of non-consolidated, clastic sedimentary deposits arranged into sand- to mud-dominated heterolithic successions, which can be upward-coarsening to upward-fining. Sediments in both the Pebas and Nauta successions range from mud to fine- to medium-grained sand. The main facies observed were 1) mud-dominated horizontal heterolithic couplets; 2) rooted brownish mud; 3) lenticular, mud-draped, cross-stratified sand; 4) mud- to sand-dominated, inclined heterolithic stratification; 5) sand-dominated horizontal heterolithic couplets; and 6) mud-draped, trough cross-stratified sand. Locally, tidal rhythmites were documented. The facies are interpreted as: 1) muddy, shallow, subaqueous flats/shoals; 2) palaeosols; 3) secondary tidal channels or run-off creeks; 4) tidally influenced point bars; 5) shoreface deposits; and 6) subtidal compound dunes. Thalassinoides-dominated Glossifungites ichnofacies, low-diversity expressions of the Skolithos ichnofacies and depauperate suites consisting of elements common to the Cruziana ichnofacies strongly indicate brackish-water conditions. However, continental trace fossil assemblages, with possible elements common to the Scoyenia ichnofacies, have also been identified. In addition to the palaeoenvironmental study, a local hydrogeochemical characterisation of the Pebas and Nauta formations was also conducted. The geochemistry of the groundwaters reflects the characteristics and the soil geochemistry of the geological formations studied. The Pebas formation has low hardness, acid to neutral waters, whereas the upper Pebas has high hardness, acid to neutral waters. In both units, the arsenic content is locally high. The Nauta formation has low hardness acid groundwaters. A regional review of the Pebas and Nauta formations placed the local observations into a continental perspective and suggests that the whole Pebas-Nauta system was a probably shallow (some tens of metres at maximum), brackish- to freshwater, tidally-influenced epicontinental embayment with a probable semi-diurnal to mixed tidal regime and a microtidal range, surrounded by continental environments such as forest floors, lagoons, rivers and their flood plains, and lakes.