39 research outputs found
Seasonal and annual fluxes of nutrients and organic matter from large rivers to the Arctic Ocean and surrounding seas
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 35 (2012): 369-382, doi:10.1007/s12237-011-9386-6.River inputs of nutrients and organic matter impact the biogeochemistry of arctic
estuaries and the Arctic Ocean as a whole, yet there is considerable uncertainty about the
magnitude of fluvial fluxes at the pan-arctic scale. Samples from the six largest arctic
rivers, with a combined watershed area of 11.3 x 106 km2, have revealed strong seasonal
variations in constituent concentrations and fluxes within rivers as well as large
differences among the rivers. Specifically, we investigate fluxes of dissolved organic
carbon, dissolved organic nitrogen, total dissolved phosphorus, dissolved inorganic
nitrogen, nitrate, and silica. This is the first time that seasonal and annual constituent
fluxes have been determined using consistent sampling and analytical methods at the pan
arctic scale, and consequently provide the best available estimates for constituent flux
from land to the Arctic Ocean and surrounding seas. Given the large inputs of river water
to the relatively small Arctic Ocean, and the dramatic impacts that climate change is
having in the Arctic, it is particularly urgent that we establish the contemporary river
fluxes so that we will be able to detect future changes and evaluate the impact of the
changes on the biogeochemistry of the receiving coastal and ocean systems.This work was supported by the National Science Foundation through grants
OPP-0229302, OPP-0519840, OPP-0732522, and OPP-0732944. Additional support was
provided by the U. S. Geological Survey (Yukon River) and the Department of Indian
and Northern Affairs (Mackenzie River)
The processing and impact of dissolved riverine nitrogen in the Arctic Ocean
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 35 (2012): 401-415, doi:10.1007/s12237-011-9417-3.Although the Arctic Ocean is the most riverine-influenced of all of the worldâs oceans, the importance of terrigenous nutrients in this environment is poorly understood. This study couples estimates of circumpolar riverine nutrient fluxes from the PARTNERS (Pan-Arctic River Transport of Nutrients, Organic Matter, and Suspended Sediments) Project with a regionally configured version of the MIT general circulation model to develop estimates of the distribution and availability of dissolved riverine N in the Arctic Ocean, assess its importance for primary production, and compare these estimates to potential bacterial production fueled by riverine C. Because riverine dissolved organic nitrogen is remineralized slowly, riverine N is available for uptake well into the open ocean. Despite this, we estimate that even when recycling is considered, riverine N may support 0.5â1.5 Tmol C yearâ1 of primary production, a small proportion of total Arctic Ocean photosynthesis. Rapid uptake of dissolved inorganic nitrogen coupled with relatively high rates of dissolved organic nitrogen regeneration in N-limited nearshore regions, however, leads to potential localized rates of riverine-supported photosynthesis that represent a substantial proportion of nearshore production.Funding for this work was provided through NSFOPP-
0229302 and NSF-OPP-0732985.Support to SET was additionally
provided by an NSERC Postdoctoral Fellowship
Hydroclimatic variability and predictability: A survey of recent research
Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land-atmosphere coupling, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative examples of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative examples clearly show that current research into hydroclimatic variability is strong, vibrant, and multifaceted