TY - JOUR
T1 - Differentiating the role of different-sized microorganisms in peptide decomposition during incubations using size-fractioned coastal seawater
AU - Liu, Shuting
AU - Riesen, Alyssa
AU - Liu, Zhanfei
N1 - Publisher Copyright:
© 2015 Elsevier B.V..
PY - 2015/11/1
Y1 - 2015/11/1
N2 - Peptide decomposition by different-sized microorganisms was compared by incubating tetrapeptide alanine-valine-phenylalanine-alanine (AVFA), a fragment of RuBisCO, in coastal seawater after size-fraction by filtration. The size-fractioned seawater included < 0.8-μm filtered (free-living bacteria), < 5-μm filtered (free-living bacteria + heterotrophic nanoflagellates), < 20-μm filtered (free-living and particle-attached bacteria + heterotrophic nanoflagellates + other small protists), and unfiltered whole water collected from Texas coast in the western Gulf of Mexico. Decomposition rates of AVFA in the < 20-μm and unfiltered seawater were significantly higher than those in the < 0.8-μm and < 5-μm seawater in the December 2011 incubation. The higher decomposition rate in the large size fractions can be attributed to activities of particle-attached bacteria and/or large-size microorganisms, such as osmotrophic protists. However, the role of particle-attached bacteria in explaining this decomposition difference might be limited, as bacterial abundance and community structure did not differ much among the 4 treatments. Consistently, the June 2013 incubation indicated that AVFA decomposed most rapidly in the unfiltered seawater with > 20-μm microorganisms. This study provides insights into the relative role of different-sized microorganisms in regulating the recycling of labile organic matter in coastal waters.
AB - Peptide decomposition by different-sized microorganisms was compared by incubating tetrapeptide alanine-valine-phenylalanine-alanine (AVFA), a fragment of RuBisCO, in coastal seawater after size-fraction by filtration. The size-fractioned seawater included < 0.8-μm filtered (free-living bacteria), < 5-μm filtered (free-living bacteria + heterotrophic nanoflagellates), < 20-μm filtered (free-living and particle-attached bacteria + heterotrophic nanoflagellates + other small protists), and unfiltered whole water collected from Texas coast in the western Gulf of Mexico. Decomposition rates of AVFA in the < 20-μm and unfiltered seawater were significantly higher than those in the < 0.8-μm and < 5-μm seawater in the December 2011 incubation. The higher decomposition rate in the large size fractions can be attributed to activities of particle-attached bacteria and/or large-size microorganisms, such as osmotrophic protists. However, the role of particle-attached bacteria in explaining this decomposition difference might be limited, as bacterial abundance and community structure did not differ much among the 4 treatments. Consistently, the June 2013 incubation indicated that AVFA decomposed most rapidly in the unfiltered seawater with > 20-μm microorganisms. This study provides insights into the relative role of different-sized microorganisms in regulating the recycling of labile organic matter in coastal waters.
KW - Free-living bacteria
KW - Gammaproteobacteria
KW - Osmotrophic protists
KW - Particle-attached bacteria
KW - Peptide decomposition
KW - Size-fractioned coastal seawater
UR - http://www.scopus.com/inward/record.url?scp=84937213966&partnerID=8YFLogxK
U2 - 10.1016/j.jembe.2015.07.004
DO - 10.1016/j.jembe.2015.07.004
M3 - Article
AN - SCOPUS:84937213966
SN - 0022-0981
VL - 472
SP - 97
EP - 106
JO - Journal of Experimental Marine Biology and Ecology
JF - Journal of Experimental Marine Biology and Ecology
ER -