F. A. Mclaughlin

Fisheries and Oceans Canada | DFO

To better understand the current carbon cycle and potentially detect its change in the rapidly changing Arctic Ocean, we examined sinking particles collected quasi-continuously over a period of 7 years (2004-2011) by bottom-tethered sediment trap moorings in the central Canada Basin. Total mass flux was very low (< 100 mgm−2d−1) at all sites and wa...

Time series of ice draft from 2003-2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the Beaufort Gyre (BG), culminating in the extreme minimum in 2012. Negative trends in median ice drafts and most ice fractions are observed, while open water and thinnest ice fractions (<0....

Hydrographic data from the Arctic Ocean show that freshwater content in the Lincoln Sea, north of Greenland, increased significantly from 2007 to 2010, slightly lagging changes in the eastern and central Arctic. The anomaly was primarily caused by a decrease in the upper ocean salinity. In 2011 upper ocean salinities in the Lincoln Sea returned to...

Arctic warming is projected to continue through-out the coming century. Yet, our currently limited under-standing of the Arctic Ocean carbon cycle hinders our abil-ity to predict how changing conditions will affect local Arc-tic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-is...

Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotop...

In 2008, surface waters in the Canada Basin of the Arctic Ocean were found to be undersaturated with respect to aragonite. This is associated with recent extensive melting of sea ice in this region, as well as elevated sea surface temperature and atmospheric CO2 concentrations. We have estimated the relative contribution of each of these controllin...

Understanding the processes driving the carbon cycle in the Arctic Ocean is of fundamental importance for assessing the impacts of the predicted climate change in this critical region. We analyzed sinking particle samples intercepted below the marginal ice zone of the Beaufort Sea at a depth of 3067m (Station A, 75N, 150W) in the Canada Basin from...

We have measured full water column depth Delta14C profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and suspended particulate organic carbon (POC) collected in 2008 at two sites in the Canada Basin in the Arctic Ocean. One site is seasonally ice-covered (CB-4; 75°N, 150°W) and the other is permanently ice-covered (CB-9;...

It is expected that coastal erosion, upwelling and increased river runoff from Arctic warming will increase the concentration of suspended particles in the Arctic Ocean. Here we analyze in situ transmissometer and fluorometer data from the summers of 2003 through 2008 and bottle-derived particulate organic carbon (POC) and total suspended solids (T...

It is expected that coastal erosion, upwelling, and increased river runoff from Arctic warming will increase the concentration of suspended particles in the Arctic Ocean. Here we analyze in situ transmissometer and fluorometer data from the summers of 2003 through 2008 and bottle-derived particulate organic carbon (POC) and total suspended solids (...

Sea ice in the Canada Basin of the Arctic Ocean has decreased significantly in recent years, and this will likely change the properties of the surface waters. A near-surface temperature maximum (NSTM) at typical depths of 25-35 m has been previously described; however, its formation mechanisms, seasonal evolution, and interannual variability have n...

In 2008, there was an unprecedented amount of fresh water in the surface layer of the Arctic Ocean. The source of the fresh water was melting sea ice. The heating of the ocean in areas of extreme summer sea ice loss (for instance, summer surface water temperatures in the Beaufort Sea were more than 3°C above average) was contributing to record high...

The extent of summer Arctic sea ice has reduced dramatically in recent years and, simultaneously, we have observed surface freshening over the Canada Basin in 2006 and 2007. In order to identify the source of this fresh water, either meteoric or sea ice meltwater, salinity, δ18O, and alkalinity were analyzed. Results show that sea ice meltwater inc...

The contribution of freshwater components (e.g., meteoric, sea ice, and Pacific water) in the Canada Basin is quantified using salinity, delta 18O, and nutrient data collected in 2003 and 2004. The penetration depth of sea ice meltwater is limited to the upper 30 m, and brine, rejected during sea ice formation, is observed from 30 to 250 m depth. T...

1] The Arctic shelf is currently undergoing dramatic thermal changes caused by the continued warming associated with Holocene sea level rise. During this transgression, comparatively warm waters have flooded over cold permafrost areas of the Arctic Shelf. A thermal pulse of more than 10°C is still propagating down into the submerged sediment and ma...

The composition of Canada Basin waters in 2003 and 2004 is quantified using salinity, nutrients, and 18O. Meteoric water is the main source of freshwater in the top 50 m of the water column, whereas Pacific water is the main source between 50 m and the Atlantic water layer below. The influence of Atlantic water is limited to waters below the nutrie...

There are very few researches which investigated the relation between the large scale distributions of nutrients and biological activity in the Arctic basin. In this study, we examine the distribution of algal biomass (chlorophyll a) in an open water region of the Canada Basin, especially focused on the difference in the algal biomass between the e...

In the Arctic Ocean, Pacific source water can be distinguished from Atlantic source water by nitrate-phosphate concentration relationships, with Pacific water having higher phosphate concentrations relative to those of nitrate. Furthermore, Pacific water, originally from the inflow through Bering Strait, is clearly recognizable in the outflows of l...

Salinity and measurements were made along a shelf-basin section out to the initial SHEBA site in the Beaufort Gyre and along the SHEBA drift track to determine the sources and amounts of surface freshening observed in the Canada Basin. Abundant amounts of Mackenzie River runoff, up to of inventory in the top of the water column, were found in the i...

The effects of upstream events on southern Canada Basin waters were examined using physical and geochemical data collected at one location between 1989 and 1995. These events included Atlantic layer warming, relocation of the Atlantic/Pacific water mass boundary, and increased ventilation of boundary current waters. Early signals of change in the C...

1] This paper presents a new hypothesis along with supporting evidence that the Beaufort Gyre (BG) plays a signific ant role in regulating the Arctic climate variabili ty. We propose and demonstrate that the BG accumulates a significant amount of fresh water (FW) during one climate regime (anticyclonic) and releases this water to the North Atlantic...

Copyrighted by the American Geophysical Union During SHEBA, thin ice and freshening of the Arctic Ocean surface in the Beafort Sea led to speculation that perennial sea ice was disappearing [McPhee et al., 1998]. Since 1987, we have collected salinity, δ¹⁸O and Ba profiles near the initial SHEBA site and, in 1997, we ran a section out to SHEBA. Res...

Major changes in temperature and tracer properties within the Arctic Ocean are evident in a comparison of data obtained during the 1994 Arctic Ocean Section to earlier measurements. (1) Anomalously warm and well-ventilated waters are now found in the Nansen, Amundsen and Makarov basins, with the largest temperature differences, as much as 1 °C, in...

Hydrographic measurements from the 1994 Arctic Ocean Section show how the Makarov and Canada basins of the Arctic Ocean are related, and demonstrate their oceanographic connections to the Eurasian Basin. The inflow into the Makarov Basin consists largely of well-ventilated water within a broad band of densities from a boundary flow over the Siberia...

Temperature, salinity, nutrients, oxygen, and halocarbon data collected in the Arctic Ocean reveal a frontal structure previously unrecognized in the hydrography of the Canadian Basin. Samples were collected on a 1300-km section extending from the Beaufort Sea in the Canada Basin to the East Siberian Sea in the Makarov Basin. These data, collected...

Potential temperature (Theta) and salinity (S) data obtained along the perimeter of the southern Canadian Basin north of the East Siberian Sea in 1993 aboard the CCGS Henry Larsen show higher temperatures in waters of Atlantic origin than in available climatological data for the Canadian Basin. In particular, a front is observed near the Mendeleyev...

To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that na...

The identity and form of dissolved organic matter in rivers and oceans are fundamental to the biogeochemical cycle of carbon. In particular, understanding the phase distribution of hydrocarbon compounds is a prerequisite to predicting the transfer between phases and the impact of anthropogenic inputs of fossil fuels to the aquatic environment. Afte...

The allochthonous inputs of hydrocarbon to the Canadian Beaufort Shelf were studied by applying principal components analysis (PCA) to well-validated and rigorously blank-corrected samples. Incorporation of a wide range of perdeuterated n-alkanes and PAH into the analysis scheme ensured that only reliably quantified variables were used to interpret...

The distributions of delta(0-18), salinity, temperature, and nutrients have been used to quantify water sources to the Mackenzie shelf in the Beaufort Sea. Comparison of water mass analyses with satellite imagery confirms that the meteoric (runoff) water is associated with the Mackenzie plume. The seasonally variable surface layer for the shelf is...

Photo-oxidation analysis of colloidal organic material from the Mackenzie River and Beaufort Sea indicates that organic colloids in riverine, brackish, and marine waters match organic particulate material in magnitude and distribution. Comparison with data obtained by CHN analysis of organic colloids g > 0.2 μm in size indicates that most of the ri...

Chromosorb T and XAD-2 resins are compared for the in situ extraction of alkane and polycyclic aromatic hydrocarbons (PAHs) from fresh- and seawater. In column efficiency experiments, Chromosorb T yielded higher recoveries than XAD-2 for n-alkanes at 3 and 0.6 ng/L concentrations per component. Chromosorb T columns gave good recoveries for PAHs of...

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Four samples of coastal and estuarine waters collected from the Straits of Georgia were examined for the effects of storage on nutrients. Within the context of non-parametric analysis of variance the effects of freezing, quick freezing, filtering and storage time were examined. Quick freezing offered distinct advantages for phosphate storage with f...