TY - JOUR
T1 - Spatial differences in dissolved silicon utilization in Lake Baikal, Siberia: Examining the impact of high diatom biomass events and eutrophication
AU - Panizzo, V.N.
AU - Roberts, S.
AU - Swann, G.E.A.
AU - McGowan, S.
AU - Mackay, A.W.
AU - Vologina, E.
AU - Pashley, V.
AU - Horstwood, M.S.A.
N1 - CODEN: LIOCA
Funding details: University of Minnesota Duluth, UMD
Funding details: Natural Environment Research Council, NERC, NE/J007765/1, NE/J00829X/1, NE/J010227/1
Funding details: British Geological Survey, BGS
Funding text 1: The authors would like to thank Mike Sturm (EAWAG), Nikolaj M. Budnev (Irkutsk State University), the captain and crew of the Geolog research boat and Dmitry Gladkochub (IEC) in facilitating and organizing all Russian fieldwork. Thanks also go to Alison Ball and Julia Lehman (from Urban Promise Academy in Oakland) who joined our expedition to help on-board the ?Geolog.? In addition, thanks are extended to Simon Chenery and Thomas Barlow (BGS) for ICP-MS analyses of dissolved silicon concentrations. We extend our gratitude to Eugene Silow (Irkutsk State University) and Ted Ozersky (University of Minnesota Duluth) along with their colleagues for their special communications with regards to their preliminary A. baicalensis data from spring-summer 2013 sampling. This work was supported by the Natural Environment Research Council [grant numbers NE/J00829X/1, NE/J010227/1, NE/J007765/1].
PY - 2018
Y1 - 2018
N2 - Recent research has highlighted how Lake Baikal, Siberia, has responded to the direct and indirect effects of climate change (e.g., ice-cover duration), nutrient loading, and pollution, manifesting as changes in phytoplankton/zooplankton populations, community structure, and seasonal succession. Here, we combine and compare analyses of chlorophyll a (an estimate of total algal biomass), carotenoid pigments (biomarkers of algal groups), and lake water silicon isotope geochemistry (δ30SiDSi) to differentiate spatial patterns in dissolved silicon (DSi) uptake at Lake Baikal. A total of 15 sites across the three basins (south, central, and north) of Lake Baikal were sampled in August 2013 along a depth gradient of 0–180 m. Strong, significant correlations were found between vertical profiles of photic zone DSi concentrations and δ30SiDSi compositions (r = −0.81, p < 0.001), although these are strongest in the central basin aphotic zone (r = −0.98, p < 0.001). Data refute the hypothesis of DSi uptake by picocyanobacteria. Algal biomass profiles and high surface δ30SiDSi compositions suggest greater productivity in the south basin and more oligotrophic conditions in the north basin. δ30SiDSi signatures are highest at depth (20 m) in central basin sites, indicating greater (10–40%) DSi utilization at deep chlorophyll maxima. DSi limitation occurs in the pelagic central basin, probably reflecting a high diatom biomass bloom event (Aulacoseira baicalensis). Meanwhile in the more hydrologically restricted, shallow Maloe More region (central basin), both high δ30SiDSi compositions and picocyanobacteria (zeaxanthin) concentrations, respectively point to the legacy of an “Aulacoseira bloom year” and continuous nutrient supply in summer months (e.g., localized eutrophication).
AB - Recent research has highlighted how Lake Baikal, Siberia, has responded to the direct and indirect effects of climate change (e.g., ice-cover duration), nutrient loading, and pollution, manifesting as changes in phytoplankton/zooplankton populations, community structure, and seasonal succession. Here, we combine and compare analyses of chlorophyll a (an estimate of total algal biomass), carotenoid pigments (biomarkers of algal groups), and lake water silicon isotope geochemistry (δ30SiDSi) to differentiate spatial patterns in dissolved silicon (DSi) uptake at Lake Baikal. A total of 15 sites across the three basins (south, central, and north) of Lake Baikal were sampled in August 2013 along a depth gradient of 0–180 m. Strong, significant correlations were found between vertical profiles of photic zone DSi concentrations and δ30SiDSi compositions (r = −0.81, p < 0.001), although these are strongest in the central basin aphotic zone (r = −0.98, p < 0.001). Data refute the hypothesis of DSi uptake by picocyanobacteria. Algal biomass profiles and high surface δ30SiDSi compositions suggest greater productivity in the south basin and more oligotrophic conditions in the north basin. δ30SiDSi signatures are highest at depth (20 m) in central basin sites, indicating greater (10–40%) DSi utilization at deep chlorophyll maxima. DSi limitation occurs in the pelagic central basin, probably reflecting a high diatom biomass bloom event (Aulacoseira baicalensis). Meanwhile in the more hydrologically restricted, shallow Maloe More region (central basin), both high δ30SiDSi compositions and picocyanobacteria (zeaxanthin) concentrations, respectively point to the legacy of an “Aulacoseira bloom year” and continuous nutrient supply in summer months (e.g., localized eutrophication).
U2 - 10.1002/lno.10792
DO - 10.1002/lno.10792
M3 - Article
SN - 1939-5590
VL - 63
SP - 1562
EP - 1578
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 4
ER -