Title Chromophoric dissolved organic matter cycling during a Ross Sea Phaeocystis antarctica bloom
Author Kieber, D.J.; Toole, D.A.; Kiene, R.P.
Author Affil Kieber, D.J., State University of New York, Department of Chemistry, Syracuse, NY. Other: Woods Hole Oceanographic Institution; University of South Alabama
Source p.319-333, ; Smithsonian at the poles, Washington, DC, May 3-4, 2007, edited by I. Krupnik, M.A. Lang and S.E. Miller. Publisher: Smithsonian Institution Scholarly Press, Washington, DC, United States. ISBN: 978-0-9788460-1-50-9788460-1- X
Publication Date 2009
Notes In English. NSF grants OPP-0230499 and OPP-0230497. 63 refs. Ant. Acc. No: 86097. CRREL Acc. No: 63004410
Index Terms algae; ecology; ice; ice cover; plant ecology; ultraviolet radiation; Southern Ocean--Ross Sea; algal blooms; diatoms; dissolved materials; electromagnetic radiation; ice cover distribution; International Polar Year 2007-08; IPY 2007-08 Research Publications; living taxa; nutrients; organic compounds; Plantae; productivity; Ross Sea; sea ice; Southern Ocean
Abstract Chromophoric dissolved organic matter (CDOM) is ubiquitous in the oceans, where it is an important elemental reservoir, a key photoreactant, and a sunscreen for ultraviolet (UV) radiation. Chromophoric dissolved organic matter is generally the main attenuator of UV radiation in the water column, and it affects the remote sensing of chlorophyll a (chl a) such that corrections for CDOM need to be incorporated into remote sensing algorithms. Despite its significance, relatively few CDOM measurements have been made in the open ocean, especially in polar regions. In this paper, we show that CDOM spectral absorption coefficients (alpha lambda ) are relatively low in highly productive Antarctic waters, ranging from approximately 0.18 to 0.30 m-1 at 300 nm and 0.014 to 0.054 m-1 at 443 nm. These values are low compared to coastal waters, but they are higher (by approximately a factor of two to three) than alpha lambda in oligotrophic waters at low latitudes, supporting the supposition of a poleward increase in alpha CDOM in the open ocean. Chromophoric dissolved organic matter alpha lambda and spectral slopes did not increase during the early development of a bloom of the colonial haptophyte Phaeocystis antarctica in the Ross Sea, Antarctica, even though chl a concentrations increased more than one- hundred-fold. Our results suggest that Antarctic CDOM in the Ross Sea is not coupled directly to algal production of organic matter in the photic zone during the early bloom but is rather produced in the photic zone at a later time or elsewhere in the water column, possibly from organic-rich sea ice or the microbial degradation of algal- derived dissolved organic matter exported out of the photic zone. Spectral alpha lambda at 325 nm for surface waters in the Southern Ocean and Ross Sea were remarkably similar to values reported for deep water from the North Atlantic by Nelson et al. in 2007. This similarity may not be a coincidence and may indicate long-range transport to the North Atlantic of CDOM produced in the Antarctic via Antarctic Intermediate and Bottom Water.
URL http://hdl.handle.net/10088/6809
Publication Type monograph
Record ID 292159