Primary production in Lake La Cruz (Spain) over the last four centuries: reconstruction based on sedimentary signal of photosynthetic pigments |
| |
Authors: | Lidia Romero-Viana Brendan J Keely Antonio Camacho Eduardo Vicente M Rosa Miracle |
| |
Institution: | 1.Department of Microbiology and Ecology, Institute Cavanilles of Biodiversity and Evolutionary Biology,University of Valencia,Burjassot, Valencia,Spain;2.Institut für Geowissenchanften,Universit?t Potsdam,Potsdam,Germany;3.Department of Chemistry,University of York,Heslington, York,UK |
| |
Abstract: | We analysed photosynthetic pigments in annually laminated sediment of meromictic Lake La Cruz, Spain, to cope with the timing
and characterisation of primary productivity changes over the last four centuries. The photosynthetic pigments identified
included chlorophyll a and b (and its derivatives) and specific carotenoids of different algal groups, such as zeaxanthin, lutein, alloxanthin, diadinoxanthin
and diatoxanthin among others. Marker pigments of phototrophic sulfur bacteria were also observed, including bacteriochlorophyll
a derivatives, homologue series of bacteriophaeophytins d and bacterial carotenoids okenone and chlorobactene. We investigated the diagenetic processes of pigment alteration in anoxic
sediments and the possible implications for paleoproductivity reconstruction and interpretation. The lack of systematic down-core
changes in diagenetic indicators suggests that variability of sedimentary pigment concentrations is the result of changes
in lake productivity. The lower concentration of algal photosynthetic pigments in the bottom of sediment sequence corresponds
to the onset of meromictic conditions. Before that, sediment was not continuously anoxic and the preservation of pigments
was reduced. Regarding photosynthetic bacteria, green sulfur bacteria derivatives indicate that population growth was limited
until the settled organic matter was sufficient to provide enough sulphide. Moreover, the presence of bacterioviridine, an
oxidised derivative of bacteriochlorophyll a, suggest the competitive relation among photosynthetic bacteria. The high relative abundance of zeaxanthin indicates the
dominance of picocyanobacteria in the primary productivity over the last centuries. Fluctuations of the pigment signal observed
in the sediment sequence during the meromictic period were well correlated with fluctuations of solar activity. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|