Quality Assurance of CO2 from Natural Gas Source For the SPRUCE Experiment

The goal of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment project, led by Oak Ridge National Laboratory (ORNL), is to observe and assess ecological responses of peatland ecosystems to increased temperatures and elevated atmospheric CO2 concentrations. Control plots are maintained at ambient temperatures and/or CO2 concentrations. Treatments are applied in a full factorial design; plots are warmed to +2.25, +4.5, +6.75, and +9oC and exposed to an atmospheric CO2 concentration of 800 to 900 ppm. These parameters are set to reflect projected temperatures and atmospheric CO2 levels in the next century. The source for the CO2 that is added comes from natural gas, a fossil fuel, which is depleted in 13C and 14C. New CO2 source tanks are delivered one to two times a week. We wanted to make sure the CO2 was consistently coming from natural gas and not other sources. We measured the δ13C and Δ14C of mixed ambient and elevated CO2 in treatment plots and ambient CO2 in control plots. Using the δ13C and Δ14C for mixed (treatment) and ambient (control) atmospheric CO2, we were able to calculate δ13C and Δ14C for elevated CO2. We found that the CO2 source consistently comes from natural gas

From the Top: Surface-derived Carbon Fuels Greenhouse Gas Production at Depth in a Neotropical Peatland

Tropical peatlands play an important role in global carbon (C) cycling but little is known about factors driving carbon dioxide (CO2) and methane (CH4) emissions from these ecosystems, especially production below the surface. This study aimed to identify source material and processes regulating C emissions from deep in a Neotropical peatland on the Caribbean coast of Panama. We hypothesized that: 1) surface derived organic matter transported down the soil profile is the primary C source for respiration products at depth and 2) high lignin content results in hydrogenotrophic methanogenesis as the dominant CH4 production pathway throughout the profile. We used radiocarbon isotopes to determine whether CO2 and CH4 at depth (measured to 2 m) are produced from modern substrates or ancient deep peat, and we used stable C isotopes to identify the dominant CH4 production pathway. Peat organic chemistry was characterized using 13C solid state nuclear magnetic resonance spectroscopy (13C-NMR). We found that deep peat respiration products had radiocarbon signatures that were more similar to surface dissolved organic C (DOC) than deep solid peat. Radiocarbon ages for deep peat ranged from 1200 – 1800 yrBP at the sites measured. These results indicate that surface derived C was the dominant source for gas production at depth in this peatland, likely because of vertical transport of DOC from the surface to depth. Carbohydrates did not vary with depth across these sites, whereas lignin, which was the most abundant compound (55–70 % of C), tended to increase with depth. These results suggest that there is no preferential decomposition of carbohydrates, but preferential retention of lignin. Stable isotope signatures of respiration products indicated that hydrogenotrophic rather than acetoclastic methanogenesis was the dominant production pathway of CH4 throughout the peat profile. These results suggest, even C compounds that are typically considered vulnerable to decomposition (i.e., carbohydrates) are preserved deep in these tropical peats, highlighting the importance of anaerobic, waterlogged conditions for preserving tropical peatland C

Temperature relations of central Oregon marine intertidal invertebrates : a prepublication technical report to the Office of Naval Research

This report is concerned with environmental and animal internal temperatures in the intertidal zone at low tide. Daily sea surface temperatures at Agate Beach, Ore., are compared to weekly measurements made near-by. Greater range and fluctuations are revealed by daily measurements. Data are provided on animal internal temperatures at low tide in early summer for 16 common invertebrates of the rocky intertidal, and some heating rates for 4 of these species. Internal temperature and heating rates were obtained for the sea urchin, Strongylocentrotus purpuratus, in June, 1968, during a heat-kill period. All species were found to normally sustain as much as 10°C increases above sea surface temperatures at low tide in early summer. Implications of this for other aspects of the biology of the intertidal fauna are discussed. The hypothesis is advanced that intertidal invertebrates require a temperature regime which includes as seasonal variations both the low and high temperatures experienced at low tide. The increased digestive and assimilative efficiency produced by summer low tide high internal temperatures may be necessary for successful food utilization and gonad reserve build-up

Antarctic Marine Biodiversity – What Do We Know About the Distribution of Life in the Southern Ocean?

The remote and hostile Southern Ocean is home to a diverse and rich community of life that thrives in an environment dominated by glaciations and strong currents. Marine biological studies in the region date back to the nineteenth century, but despite this long history of research, relatively little is known about the complex interactions between the highly seasonal physical environment and the species that inhabit the Southern Ocean. Oceanographically, the Southern Ocean is a major driver of global ocean circulation and plays a vital role in interacting with the deep water circulation in each of the Pacific, Atlantic, and Indian oceans. The Census of Antarctic Marine Life and the Scientific Committee on Antarctic Research Marine Biodiversity Information Network (SCAR-MarBIN) have strived to coordinate and unify the available scientific expertise and biodiversity data to improve our understanding of Southern Ocean biodiversity. Taxonomic lists for all marine species have been compiled to form the Register of Antarctic Marine Species, which currently includes over 8,200 species. SCAR-MarBIN has brought together over 1 million distribution records for Southern Ocean species, forming a baseline against which future change can be judged. The sample locations and numbers of known species from different regions were mapped and the depth distributions of benthic samples plotted. Our knowledge of the biodiversity of the Southern Ocean is largely determined by the relative inaccessibility of the region. Benthic sampling is largely restricted to the shelf; little is known about the fauna of the deep sea. The location of scientific bases heavily influences the distribution pattern of sample and observation data, and the logistical supply routes are the focus of much of the at-sea and pelagic work. Taxa such as mollusks and echinoderms are well represented within existing datasets with high numbers of georeferenced records. Other taxa, including the species-rich nematodes, are represented by just a handful of digital records

Genetic Population Structure in the Antarctic Benthos: Insights from the Widespread Amphipod, Orchomenella franklini

Currently there is very limited understanding of genetic population structure in the Antarctic benthos. We conducted one of the first studies of microsatellite variation in an Antarctic benthic invertebrate, using the ubiquitous amphipod Orchomenella franklini (Walker, 1903). Seven microsatellite loci were used to assess genetic structure on three spatial scales: sites (100 s of metres), locations (1–10 kilometres) and regions (1000 s of kilometres) sampled in East Antarctica at Casey and Davis stations. Considerable genetic diversity was revealed, which varied between the two regions and also between polluted and unpolluted sites. Genetic differentiation among all populations was highly significant (FST = 0.086, RST = 0.139, p<0.001) consistent with the brooding mode of development in O. franklini. Hierarchical AMOVA revealed that the majority of the genetic subdivision occurred across the largest geographical scale, with Nem≈1 suggesting insufficient gene flow to prevent independent evolution of the two regions, i.e., Casey and Davis are effectively isolated. Isolation by distance was detected at smaller scales and indicates that gene flow in O. franklini occurs primarily through stepping-stone dispersal. Three of the microsatellite loci showed signs of selection, providing evidence that localised adaptation may occur within the Antarctic benthos. These results provide insights into processes of speciation in Antarctic brooders, and will help inform the design of spatial management initiatives recently endorsed for the Antarctic benthos

The genetic mating system of a sea spider with male-biased sexual size dimorphism: evidence for paternity skew despite random mating success

Male-biased size dimorphism is usually expected to evolve in taxa with intense male–male competition for mates, and it is hence associated with high variances in male mating success. Most species of pycnogonid sea spiders exhibit female-biased size dimorphism, and are notable among arthropods for having exclusive male parental care of embryos. Relatively little, however, is known about their natural history, breeding ecology, and mating systems. Here we first show that Ammothella biunguiculata, a small intertidal sea spider, exhibits male-biased size dimorphism. Moreover, we combine genetic parentage analysis with quantitative measures of sexual selection to show that male body size does not appear to be under directional selection. Simulations of random mating revealed that mate acquisition in this species is largely driven by chance factors, although actual paternity success is likely non-randomly distributed. Finally, the opportunity for sexual selection (Is), an indirect metric for the potential strength of sexual selection, in A. biunguiculata males was less than half of that estimated in a sea spider with female-biased size dimorphism, suggesting the direction of size dimorphism may not be a reliable predictor of the intensity of sexual selection in this group. We highlight the suitability of pycnogonids as model systems for addressing questions relating parental investment and sexual selection, as well as the current lack of basic information on their natural history and breeding ecology

The Asian decapod Hemigrapsus penicillatus (de Haan, 1835) (Grapsidae, Decapoda) introduced in European waters: status quo and future perspectives

The Asian decapod Hemigrapsus penicillatus (de Haan, 1835) was first recorded in European waters in 1994. The first specimens were collected in the estuary of Charente Maritime on the west coast of France close to La Rochelle. The current range in Europe covers Spanish shallow water habitats of the Bay of Biscay to areas north of La Rochelle (France). Densities of up to 20 specimens per square metre occur. This species has a high temperature and salinity tolerace and will expand its distribution in European waters. It is not clear whether this crab was introduced by shipping in ballast water or as a fouling organism. Based on a study of ship hull fouling in German dry docks this account provides evidence that hull fouling is a likely vector for the introduction of this crab. In August 1993, six juvenile specimens of H. penicillatus were removed from the hull of a car-carrier. After its journey from Japan into European waters this vessel docked in the port of Bremerhaven (Germany) for a routine inspection and coating with antifouling paint