Sand fraction, organic carbon and nitrogen data, and calculated marine and terrestrial organic carbon fractions of surface sediments in the western Barents Sea

There is generally a lack of knowledge on how marine organic carbon accumulation is linked to vertical export and primary productivity patterns. In this study, a multi-proxy geochemical and organic-sedimentological approach is coupled with organic facies modelling focusing on regional calculations of carbon cycling and carbon burial on the western Barents Shelf between northern Scandinavia and Svalbard. OF-Mod 3D, an organic facies modelling software tool, is used to reconstruct the marine and terrestrial organic carbon fractions and to make inferences about marine primary productivity in this region. The model is calibrated with an extensive sample dataset and reproduces the present-day regional distribution of the organic carbon fractions well. Based on this new organic facies model, we present regional carbon mass accumulation rate calculations for the western Barents Sea. The calibration dataset includes location and water depth, sand fraction, organic carbon and nitrogen data and calculated marine and terrestrial organic carbon fractions.

Short- and long-term conditioning of a temperate marine diatom community to acidification and warming

Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated pCO2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and pCO2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into 'artificial' communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned 'artificial' community experiments was similar, despite differences such as the loss of two species in the latter. pCO2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes.

Extraordinarily high spider densities on islands: flow of energy from the marine to terrestrial food webs and the absence of predation.

Some islands in the Gulf of California support very high densities of spiders. Spider density is negatively correlated with island size; many small islands support 50-200 spiders per m3 of cactus. Energy for these spiders comes primarily from the ocean and not from in situ productivity by land plants. We explicitly connect the marine and terrestrial systems to show that insular food webs represent one endpoint of the marine web. We describe two conduits for marine energy entering these islands: shore drift and seabird colonies. Both conduits are related to island area, having a much stronger effect on smaller islands. This asymmetric effect helps to explain the exceptionally high spider densities on small islands. Although productivity sets the maximal potential densities, predation (by scorpions) limits realized spider abundance. Thus, prey availability and predation act in concert to set insular spider abundance.

Mixed-charge copolymer as environmentally friendly low fouling marine coatings

Thesis (Master's)--University of Washington, 2016-06

Does terrestrial epidemiology apply to marine systems?

Most of epidemiological theory has been developed for terrestrial systems, but the significance of disease in the ocean is now being recognized. However, the extent to which terrestrial epidemiology can be directly transferred to marine systems is uncertain. Many broad types of disease-causing organism occur both on land and in the sea, and it is clear that some emergent disease problems in marine environments are caused by pathogens moving from terrestrial to marine systems. However, marine systems are qualitatively different from terrestrial environments, and these differences affect the application of modelling and management approaches that have been developed for terrestrial systems. Phyla and body plans are more diverse in marine environments and marine organisms have different life histories and probably different disease transmission modes than many of their terrestrial counterparts. Marine populations are typically more open than terrestrial ones, with the potential for long-distance dispersal of larvae. Potentially, this might enable unusually rapid propagation of epidemics in marine systems, and there are several examples of this. Taken together, these differences will require the development of new approaches to modelling and control of infectious disease in the ocean.

Integration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group

The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric 'teleconnection' and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. Copyright (c) 2006 John Wiley & Sons, Ltd.

The importance of marine subsidies for terrestrial consumers in coastal Peru

The Peruvian coast is one the best examples of cross-ecosystem food web exchanges, in which resources from one of the richest marine ecosystems subsidize consumers in one of the driest deserts on Earth. Marine subsidies are resources that originate in the marine ecosystem, and that contribute to increase the density of consumers in the recipient ecosystem. I examined the effects of marine subsidies on animal populations in the Peruvian coastal desert. ^ I combined several approaches to study the linkages between marine resources and terrestrial consumers, such as surveying the spatial distribution and estimating the relative abundance of terrestrial consumers, studying the diet of geckos and lizards through stomach content analyses, and examining the desert food web with carbon and nitrogen stable isotope analyses. ^ I found that the distribution and diet of desert consumers were tightly coupled to the availability of marine subsidies. I revealed linkages along two pathways of nutrient fluxes: tidal action that washes ashore macroalgae and cadavers of marine organisms, and animal transport in places where pinnipeds and seabirds congregate for reproduction. In the first pathway, intertidal algivivores made marine resources available to terrestrial consumers by moving between the intertidal and supratidal zone. The relative contribution of terrestrial and algal carbon sources varied among terrestrial consumers, because scorpions assimilated a lower proportion of energy from macroalgae than did geckos and solifuges. In the second pathway, I found that pinniped colonies influenced the diet of desert consumers, and contributed to support large populations of lizards and geckos. By combining field observations, and stomach and stable isotope analyses, I constructed a simplified food web for a large sea lion colony, showing the number of trophic levels that originate from pinniped-derived nutrients. ^ My study demonstrates the enormous importance of marine resources for the diet of desert consumers. The near absence of rainfall along the Peruvian coast promotes an extreme dependence of terrestrial consumers on marine resources, and causes permanent food web effects that are affected by temporal variability in marine productivity, rather then temporal patterns of desert plant growth. ^

Pollen profile and age determination for sediment core M72/5_619-1 (22-GC3)

Sediments from the Black Sea, a region historically dominated by forests and steppe landscapes, are a valuable source of detailed information on the changes in regional terrestrial and aquatic environments at decadal to millennial scales. Here we present multi-proxy environmental records (pollen, dinoflagellate cysts, Ca, Ti and oxygen isotope data) from the uppermost 305 cm of the core 22-GC3 (42°13.53' N, 36°29.55' E) collected from a water depth of 838 m in the southern part of the Black Sea in 2007. The records span the last ~ 18 kyr (all ages are given in cal kyr BP). The pollen data reveal the dominance of the Artemisia-steppe in the region, suggesting rather dry/cold environments ~ 18-14.5 kyr BP. Warming/humidity increase during melt-water pulses (~ 16.1-14.5 kyr BP), indicated by d18O records from the 22-GC3 core sediment and from the Sofular Cave stalagmite, is expressed in more negative d13C values from the Sofular Cave, usually interpreted as the spreading of C3 plants. The records representing the interstadial complex (~ 14.5-12.9 kyr BP) show an increase in temperature and moisture, indicated by forest development, increased primary productivity and reduced surface run-off, whereas the switch from primary terrigenous to primary authigenic Ca origin occurs ~ 500 yr later. The Younger Dryas cooling is clearly demonstrated by more negative d13C values from the Sofular Cave and a reduction of pines. The early Holocene (11.7-8.5 kyr BP) interval reveals relatively dry conditions compared to the mostly moist and warm middle Holocene (8.5-5 kyr BP), which is characterized by the establishment of the species-rich warm mixed and temperate deciduous forests in the low elevation belt, temperate deciduous beech-hornbeam forests in the middle and cool conifer forest in upper mountain belt. The border between the early and middle Holocene in the vegetation records coincides with the opening of the Mediterranean corridor at ~ 8.3 kyr BP, as indicated by a marked change in the dinocyst assemblages and in the sediment lithology. Changes in the pollen assemblages indicate a reduction in forest cover after ~ 5 kyr BP, which was likely caused by increased anthropogenic pressure on the regional vegetation.

Hydrogen isotope compositions of terrestrial plant-wax n-alkanes analysed on a transect of marine surface sediment samples from 1°N to 28°S off southwest Africa

A transect of marine surface sediment samples from 1° N to 28° S off southwest Africa was analysed to verify the application of hydrogen isotope compositions of terrestrial plant-wax n-alkanes preserved in ocean sediments as a proxy for continental hydrological conditions. Conditions on the adjacent continent range from humid evergreen forests to deciduous forests, wood- and shrub land and further to arid grasslands and deserts. The hydrogen isotope values for the dominant n-alkane homologues (C29, C31 and C33) vary from -123 per mil to -141 per mil VSMOW and correlate with the modelled hydrogen isotope composition of mean annual and growing season precipitation of postulated continental source areas (r up to 0.8, p < 0.01). The apparent hydrogen isotope fractionation between alkanes and mean annual precipitation is remarkably uniform (-109 per mil on average, Sigma <= 5 per mil, n = 27). Potentially, effects of aridity on the apparent hydrogen isotope fractionation are concealed by the contribution of different plants (C3 dicotyledons vs C4 grasses). Thus, isotope ratios of leaf wax n-alkanes preserved in ocean margin sediments in these and similar tropical regions may be directly converted to dD ratios of ancient precipitation by employing a constant hydrogen isotope fractionation.

Co-digestion of terrestrial plant biomass with marine macro-algae for biogas production

This paper investigates factors affecting anaerobic degradation of marine macro-algae (or seaweed), when used as a co-substrate with terrestrial plant biomass for the production of biogas. Using Laminaria digitata, a brown marine seaweed species and green peas, results showed that when only 2% of feedstock of a reactor treating the green peas at an organic loading rate (OLR) of 2.67 kg VS.m3.day-1 was replaced with the seaweed, methane production was disrupted, whilst acidogenesis, seemed to be less adversely affected, resulting in excessive volatile acids accumulation. Reactor stability was difficult to achieve thereafter. The experiment was repeated with a lower initial OLR of green peas of 0.70 kg VS.m3.day-1 before the addition of the seaweed. Although similar symptoms as in first trial were observed, process stability was restored through the control of OLR and alkalinity. These measures led to an increase in overall OLR of 1.25 kg VS.m3.day-1 comprising of 35% seaweed. This study has shown that certain seaweed constituents are more inhibitory to the methanogens even at trace concentrations than to the other anaerobic digestion microbial groups. Appropriate adaptation strategy, involving initial low proportion of the seaweed relative to the total OLR, and overall low OLR, is necessary to ensure effective adaptation of the microorganisms to the inhibitory constituents of seaweed. Where there is seasonal availability of seaweed, the results of this study suggest that a fresh adaptation or start-up strategy must be implemented during each cycle of seaweed availability in order to ensure sustainable process stability.

Brachyuran soft-bottom assemblage from marine shallow waters in the southeastern Brazilian littoral.

The present investigation examined the assemblages of brachyuran crabs in three bays of southeastern So Paulo State, analyzing the numbers of species and individuals, biomass, and diversity. The crabs were collected monthly in Ubatumirim, Ubatuba, and Mar Virado bays in the Ubatuba region over 2 years (1998 and 1999). In each bay, six tows were made from a fishing boat. A total of 39,820 specimens, representing 11 super families, 39 genera, and 65 species of brachyurans, were obtained. The mean number of specimens and biomass varied seasonally, which can be mainly related with the population tendencies of two dominant species in the area (Callinectes ornatus and Hepatus pudibundus). The highest numbers of individuals and species were found in Ubatuba Bay, followed by Ubatumirim and Mar Virado. The highest diversity index was estimated for Ubatumirim (H' = 2.44), followed by Ubatuba (H' = 2.37) and Mar Virado (H' = 1.86). In general, the coastal region supported high abundance and species richness concerning brachyurans, with high diversity indices, probably because of its more-heterogeneous substrate, which may afford more refuges for certain species. These results suggested that environmental conditions in this area, although they showed certain differences, are favorable for the establishment and development of a diverse brachyuran guild.