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Cheng-Shiuan Lee, Nicholas S Fisher
Methylmercury (MeHg) is known to biomagnify in marine food chains, resulting in higher concentrations in upper trophic level animals than their prey. To better understand how marine copepods, an important intermediate between phytoplankton and forage fish at the bottom of the food chain, assimilate and release MeHg, we performed a series of laboratory experiments using the gamma-emitting radiotracer (203) Hg(2+) and Me(203) Hg with the calanoid copepod Acartia tonsa. Assimilation efficiencies (AEs) of Hg(2+) and MeHg ranged from 25 to 31% and 58 to 79%, respectively, depending on algal diets...
October 20, 2016: Environmental Toxicology and Chemistry
Robert P Ellis, Mauricio A Urbina, Rod W Wilson
Exponentially rising CO2 (currently ~400 μatm) is driving climate change and causing acidification of both marine and freshwater environments. Physiologists have long known that CO2 directly affects acid-base and ion regulation, respiratory function and aerobic performance in aquatic animals. More recently, many studies have demonstrated that elevated CO2 projected for end of this century (e.g. 800-1000 μatm) can also impact physiology, and have substantial effects on behaviours linked to sensory stimuli (smell, hearing and vision) both having negative implications for fitness and survival...
October 20, 2016: Global Change Biology
Pedro H C Pereira, Marcus Santos, Daniel L Lippi, Pedro Silva
Parrotfish are fundamental species in controlling algal phase-shifts and ensuring the resilience of coral reefs. Nevertheless, little is known on their ecological role in the south-western Atlantic Ocean. The present study analysed the ontogenetic foraging activity and feeding selectivity of the Brazilian endemic parrotfish Scarus zelindae using behavioural observation and benthic composition analyses. We found a significant negative relationship between fish size and feeding rates for S. zelindae individuals...
2016: PeerJ
Liina Pajusalu, Georg Martin, Tiina Paalme, Arno Põllumäe
Anthropogenic carbon dioxide (CO2) emissions to the atmosphere are causing reduction in the global ocean pH, also known as ocean acidification. This change alters the equilibrium of different forms of dissolved inorganic carbon in seawater that macroalgae use for their photosynthesis. In the Baltic Sea, benthic macroalgae live in a highly variable environment caused by seasonality and rapid changes in meteorological conditions. The effect of increasing water CO2 concentration on the net photosynthesis of the red macroalgae Furcellaria lumbricalis (Hudson) Lamouroux was tested in short-term mesocosm experiments conducted in Kõiguste Bay (N Gulf of Riga) in June-July 2012 and 2013...
2016: PeerJ
Ana C Henriques, Rui M S Azevedo, Paolo De Marco
Methanesulfonic acid (MSA) is a relevant intermediate of the biogeochemical cycle of sulfur and environmental microorganisms assume an important role in the mineralization of this compound. Several methylotrophic bacterial strains able to grow on MSA have been isolated from soil or marine water and two conserved operons, msmABCD coding for MSA monooxygenase and msmEFGH coding for a transport system, have been repeatedly encountered in most of these strains. Homologous sequences have also been amplified directly from the environment or observed in marine metagenomic data, but these showed a base composition (G + C content) very different from their counterparts from cultivated bacteria...
2016: PeerJ
Alba Ardura, Elvira Morote, Marc Kochzius, Eva Garcia-Vazquez
Mid-trophic pelagic fish are essential components of marine ecosystems because they represent the link between plankton and higher predators. Moreover, they are the basis of the most important fisheries resources; for example, in African waters. In this study, we have sampled pelagic fish larvae in the Eastern Atlantic Ocean along a latitudinal gradient between 37°N and 2°S. We have employed Bongo nets for plankton sampling and sorted visually fish and fish larvae. Using the cytochrome oxidase I gene (COI) as a DNA barcode, we have identified 44 OTUs down to species level that correspond to 14 families, with Myctophidae being the most abundant...
2016: PeerJ
Clemens Glombitza, Rishi R Adhikari, Natascha Riedinger, William P Gilhooly, Kai-Uwe Hinrichs, Fumio Inagaki
Sulfate reduction is the predominant anaerobic microbial process of organic matter mineralization in marine sediments, with recent studies revealing that sulfate reduction not only occurs in sulfate-rich sediments, but even extends to deeper, methanogenic sediments at very low background concentrations of sulfate. Using samples retrieved off the Shimokita Peninsula, Japan, during the Integrated Ocean Drilling Program (IODP) Expedition 337, we measured potential sulfate reduction rates by slurry incubations with (35)S-labeled sulfate in deep methanogenic sediments between 1276...
2016: Frontiers in Microbiology
Kensuke Hori, Tomohiko Tsuruta, Chihiro Odani, Hitomi Ono, Rieko Ohkubo, Kanoko Shimoji, Junko Murakami, Mio Nakagawa, Lina Tashima, Kimihiko Ito
OBJECTIVES: Treatment for ovarian cancer with bevacizumab(Bmab)has been covered by public medical insurance in Japan since November 2013. It is recommended that the use of Bmab is limited to the first treatment for FIGO stage III or IV ovarian cancer. The OCEAN trial for platinum sensitivity in relapsed patients and the AURELIA trial for platinum-resistance in relapsed patients were performed, and both significantly improved progression-free survival. METHOD: We retrospectively studied patients receiving Bmab with an anticancer agent for recurrent ovarian cancer...
October 2016: Gan to Kagaku Ryoho. Cancer & Chemotherapy
James N Moum, Kandaga Pujiana, Ren-Chieh Lien, William D Smyth
Dynamical understanding of the Madden-Julian Oscillation (MJO) has been elusive, and predictive capabilities therefore limited. New measurements of the ocean's response to the intense surface winds and cooling by two successive MJO pulses, separated by several weeks, show persistent ocean currents and subsurface mixing after pulse passage, thereby reducing ocean heat energy available for later pulses by an amount significantly greater than via atmospheric surface cooling alone. This suggests that thermal mixing in the upper ocean from a particular pulse might affect the amplitude of the following pulse...
October 19, 2016: Nature Communications
Bryony A Caswell, Christopher L J Frid
Global warming during the Early Jurassic, and associated widespread ocean deoxygenation, was comparable in scale with the changes projected for the next century. This study quantifies the impact of severe global environmental change on the biological traits of marine communities that define the ecological roles and functions they deliver. We document centennial-millennial variability in the biological trait composition of Early Jurassic (Toarcian) seafloor communities and examine how this changed during the event using biological traits analysis...
October 18, 2016: Oecologia
Roberto Danovaro, Antonio Dell'Anno, Cinzia Corinaldesi, Eugenio Rastelli, Ricardo Cavicchioli, Mart Krupovic, Rachel T Noble, Takuro Nunoura, David Prangishvili
Viruses are the most abundant biological entities in the world's oceans, and they play a crucial role in global biogeochemical cycles. In deep-sea ecosystems, archaea and bacteria drive major nutrient cycles, and viruses are largely responsible for their mortality, thereby exerting important controls on microbial dynamics. However, the relative impact of viruses on archaea compared to bacteria is unknown, limiting our understanding of the factors controlling the functioning of marine systems at a global scale...
October 2016: Science Advances
Leah Marie Sloan, Sarah Mincks Hardy
Rhizocephalan barnacles in the genus Briarosaccus parasitize and castrate king crab hosts, thereby preventing host reproduction and potentially altering host abundance. To better understand how environmental factors in Alaska may influence Briarosaccus prevalence, we studied the effects of temperature and salinity on the larvae of Briarosaccus regalis (previously B. callosus). Nauplius larvae were reared at 7 temperatures (2 to 16 C) and 8 salinities (19 to 40) to determine larval survival and development rates...
October 18, 2016: Journal of Parasitology
Adam E Brummett, Mishtu Dey
The marine microbial catabolism of dimethylsulfoniopropionate (DMSP) by the lyase pathway liberates ~300 million tons of dimethylsulfide (DMS) per year, which plays a major role in the biogeochemical cycling of sulfur. Recent biochemical and structural studies of some DMSP lyases, including DddQ reveal the importance of divalent transition metal ions in assisting DMSP cleavage. While DddQ is believed to be zinc-dependent primarily based on structural studies, excess zinc inhibits the enzyme. We examine the importance of iron in regulating the DMSP β-elimination reaction catalyzed by DddQ as our as-isolated purple-colored enzyme possesses ~0...
October 18, 2016: Biochemistry
Afshin Pourmokhtarian, Charles T Driscoll, John L Campbell, Katharine Hayhoe, Anne M K Stoner
Assessments of future climate change impacts on ecosystems typically rely on multiple climate model projections, but often utilize only one downscaling approach trained on one set of observations. Here, we explore the extent to which modeled biogeochemical responses to changing climate are affected by the selection of the climate downscaling method and training observations used at the montane landscape of the Hubbard Brook Experimental Forest, New Hampshire, USA. We evaluated three downscaling methods: the delta method (or the change factor method), monthly quantile mapping (Bias Correction-Spatial Disaggregation, or BCSD), and daily quantile regression (Asynchronous Regional Regression Model, or ARRM)...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
Teunis Jansen, Søren Post, Trond Kristiansen, Guðmundur J Óskarsson, Jesper Boje, Brian R MacKenzie, Mala Broberg, Helle Siegstad
Geographic redistribution of living natural resources changes access and thereby harvesting opportunities between countries. Internationally shared fish resources can be sensitive to shifts in the marine environment and this may have great impact on the economies of countries and regions that rely most heavily on fisheries to provide employment and food supply. Here we present a climate change-related biotic expansion of a rich natural resource with substantial economic consequences, namely the appearance of northeast Atlantic mackerel (Scomber scombrus) in Greenlandic waters...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Jacob L Moore, Romuald N Lipcius, Brandon Puckett, Sebastian J Schreiber
Structured population models, particularly size- or age-structured, have a long history of informing conservation and natural resource management. While size is often easier to measure than age and is the focus of many management strategies, age-structure can have important effects on population dynamics that are not captured in size-only models. However, relatively few studies have included the simultaneous effects of both age- and size-structure. To better understand how population structure, particularly that of age and size, impacts restoration and management decisions, we developed and compared a size-structured integral projection model (IPM) and an age- and size-structured IPM, using a population of Crassostrea gigas oysters in the northeastern Pacific Ocean...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Guohua Shi, Changhui Peng, Meng Wang, Shengwei Shi, Yanzheng Yang, Junyao Chu, Junjun Zhang, Guanghui Lin, Yan Shen, Qiuan Zhu
The lateral transport of dissolved organic carbon (DOC) plays an important role in linking the carbon cycles of terrestrial and aquatic ecosystems. Neglecting the lateral flow of dissolved organic carbon can lead to an underestimation of the organic carbon budget of terrestrial ecosystems. It is thus necessary to integrate DOC concentrations and flux into carbon cycle models, particularly with regard to the development of models that are intended to directly link terrestrial and ocean carbon cycles. However, to achieve this goal, more accurate information is needed to better understand and predict DOC dynamics...
2016: PloS One
Jia Xu, Zuzhen Huang, Liang Yan, Xu Zhou, Furu Zhang, Teng Long
For modern synthetic aperture radar (SAR), it has much more urgent demands on ground moving target indication (GMTI), which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA) can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target's signal-to-clutter ratio (SCR) as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering...
October 12, 2016: Sensors
Mónica Rouco, Sheean T Haley, Harriet Alexander, Samuel T Wilson, David M Karl, Sonya T Dyhrman
Populations of nitrogen-fixing cyanobacteria in the genus Trichodesmium are critical to ocean ecosystems, yet predicting patterns of Trichodesmium distribution and their role in ocean biogeochemistry is an ongoing challenge. This may, in part, be due to differences in the physiological ecology of Trichodesmium species, which are not typically considered independently in field studies. In this study, the abundance of the two dominant Trichodesmium clades (Clade I and Clade III) was investigated during a survey at Station ALOHA in the North Pacific Subtropical Gyre (NPSG) using a clade-specific qPCR approach...
October 18, 2016: Environmental Microbiology Reports
D Szalaj, M R De Orte, T A Goulding, I D Medeiros, T A DelValls, A Cesar
The study assesses the effects of carbon dioxide capture and storage (CCS) leaks and ocean acidification (OA) on the metal bioavailability and reproduction of the mytilid Perna perna. In laboratory-scale experiments, CCS leakage scenarios (pH 7.0, 6.5, 6.0) and one OA (pH 7.6) scenario were tested using metal-contaminated sediment elutriates and seawater from Santos Bay. The OA treatment did not have an effect on fertilisation, while significant effects were observed in larval-development bioassays where only 16 to 27 % of larva developed normally...
October 18, 2016: Environmental Science and Pollution Research International
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