scholarly journals What can we learn from amino acids about oceanic organic matter cycling and degradation?

2021 ◽  
Author(s):  
Birgit Gaye ◽  
Niko Lahajnar ◽  
Natalie Harms ◽  
Sophie Anna Luise Paul ◽  
Tim Rixen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Column ◽  
Deep Ocean ◽  
Principal Component ◽  
Suspended Particles ◽  
Organic Matter Cycling ◽  
Biogeochemical Indicators ◽  
Chemical Conditions

Abstract. Amino acids (AA) mainly bound in proteins are major constituents of living biomass and non-living organic material in the oceanic particulate and dissolved organic matter pool. Uptake and cycling by heterotrophic organisms lead to characteristic changes in AA composition so that AA based biogeochemical indicators are often used to elucidate processes of organic matter cycling and degradation. We analyzed particulate AA in a large sample set collected in various oceanic regions covering sinking and suspended particles in the water column, sediment samples as well as dissolved AA from water column and pore water samples. The aim of this study was to test and improve the use of AA derived biogeochemical indicators as proxies for organic matter sources and degradation, and to better understand particle dynamics and interaction between the dissolved and particulate organic matter pools. A principal component analysis (PCA) of all data delineates diverging AA compositions of sinking and suspended particles with increasing water depth. A new sinking particle and sediment degradation indicator (SDI) allows a fine-tuned classification of sinking particles and sediments with respect to the intensity of degradation, which is associated with changes of bulk δ15N ratios. This new indicator furthermore is sensitive to sedimentary redox conditions and can be used to detect past anoxic early diagenesis. A second indicator emerges from the AA spectra of suspended particulate matter (SPM) in the epipelagic and that of the meso- and bathypelagic ocean and is a residence time indicator (RTI). The characteristic changes in AA patterns from shallow to deep SPM are recapitulated in the AA spectra of the dissolved organic matter (DOM) pool, so that deep SPM is more similar to DOM than to any of the other organic matter pools. This implies that there is equilibration between finely dispersed SPM and DOM in the deep sea, which may be driven by microbial activity combined with annealing and fragmentation of gels. As these processes strongly depend on physico-chemical conditions in the deep ocean, changes in quality and degradability of DOM may strongly affect the relatively large pool of suspended and dissolved AA in the ocean that amounts to 15 Pg amino acid carbon (AAC) and 89 ± 29 Pg AAC, respectively.  

scholarly journals Impact of aquaculture on distribution of dissolved organic matter in coastal Jeju Island, Korea, based on absorption and fluorescence spectroscopy

2021 ◽  
Author(s):  
Jeonghyun Kim ◽  
Yeseul Kim ◽  
Sung Eun Park ◽  
Tae-Hoon Kim ◽  
Bong-Guk Kim ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Fluorescence Spectroscopy ◽  
Dissolved Organic Matter ◽  
Coastal Water ◽  
Coastal Region ◽  
Principal Component ◽  
Distribution Patterns ◽  
Organic Pollution ◽  
Jeju Island

AbstractIn Jeju Island, multiple land-based aquafarms were fully operational along most coastal region. However, the effect of effluent on distribution and behaviours of dissolved organic matter (DOM) in the coastal water are still unknown. To decipher characteristics of organic pollution, we compared physicochemical parameters with spectral optical properties near the coastal aquafarms in Jeju Island. Absorption spectra were measured to calculate the absorption coefficient, spectral slope coefficient, and specific UV absorbance. Fluorescent DOM was analysed using fluorescence spectroscopy coupled with parallel factor analysis. Dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) were measured using high-temperature catalytic oxidation. The DOC concentration near the discharge outlet was twice higher than that in natural groundwater, and the TDN concentration exponentially increased close to the outlet. These distribution patterns indicate that aquafarms are a significant source of DOM. Herein, principal component analysis was applied to categorise the DOM origins. There were two distinct groups, namely, aquaculture activity for TDN with humic-like and high molecular weights DOM (PC1: 48.1%) and natural biological activity in the coastal water for DOC enrichment and protein-like DOM (PC2: 18.8%). We conclude that the aquafarms significantly discharge organic nitrogen pollutants and provoke in situ production of organic carbon. Furthermore, these findings indicate the potential of optical techniques for the efficient monitoring of anthropogenic organic pollutants from aquafarms worldwide.

scholarly journals An aquatic vertebrate can use amino acids from environmental water

2016 ◽  
Vol 283 (1839) ◽  
pp. 20160996 ◽  
Author(s):  
Noboru Katayama ◽  
Kobayashi Makoto ◽  
Osamu Kishida
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Dissolved Organic Matter ◽  
Larval Growth ◽  
Environmental Water ◽  
Acid Solutions ◽  
Aquatic Vertebrates ◽  
Amino Acid Solutions ◽  
Salamander Larvae

Conventional food-web theory assumes that nutrients from dissolved organic matter are transferred to aquatic vertebrates via long nutrient pathways involving multiple eukaryotic species as intermediary nutrient transporters. Here, using larvae of the salamander Hynobius retardatus as a model system, we provide experimental evidence of a shortcut nutrient pathway by showing that H. retardatus larvae can use dissolved amino acids for their growth without eukaryotic mediation. First, to explore which amino acids can promote larval growth, we kept individual salamander larvae in one of eight different high-concentration amino acid solutions, or in control water from which all other eukaryotic organisms had been removed. We thus identified five amino acids (lysine, threonine, serine, phenylalanine, and tyrosine) as having the potential to promote larval growth. Next, using 15 N-labelled amino acid solutions, we demonstrated that nitrogen from dissolved amino acids was found in larval tissues. These results suggest that salamander larvae can take up dissolved amino acids from environmental water to use as an energy source or a growth-promoting factor. Thus, aquatic vertebrates as well as aquatic invertebrates may be able to use dissolved organic matter as a nutrient source.

Efficient export of carbon to the deep ocean through dissolved organic matter

Nature ◽  
2005 ◽  
Vol 433 (7022) ◽  
pp. 142-145 ◽  
Author(s):  
Charles S. Hopkinson ◽  
Joseph J. Vallino
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Deep Ocean

scholarly journals Chloroflexi CL500-11 Populations That Predominate Deep-Lake Hypolimnion Bacterioplankton Rely on Nitrogen-Rich Dissolved Organic Matter Metabolism and C1Compound Oxidation

2015 ◽  
Vol 82 (5) ◽  
pp. 1423-1432 ◽  
Author(s):  
Vincent J. Denef ◽  
Ryan S. Mueller ◽  
Edna Chiang ◽  
James R. Liebig ◽  
Henry A. Vanderploeg
Keyword(s):  
Gene Expression ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Column ◽  
Lake Michigan ◽  
Expression Patterns ◽  
Metagenomic Data ◽  
Type I ◽  
Deep Lake ◽  
Additional Energy

ABSTRACTTheChloroflexiCL500-11 clade contributes a large proportion of the bacterial biomass in the oxygenated hypolimnia of deep lakes worldwide, including the world's largest freshwater system, the Laurentian Great Lakes. Traits that allow CL500-11 to thrive and its biogeochemical role in these environments are currently unknown. Here, we found that a CL500-11 population was present mostly in offshore waters along a transect in ultraoligotrophic Lake Michigan (a Laurentian Great Lake). It occurred throughout the water column in spring and only in the hypolimnion during summer stratification, contributing up to 18.1% of all cells. Genome reconstruction from metagenomic data suggested an aerobic, motile, heterotrophic lifestyle, with additional energy being gained through carboxidovory and methylovory. Comparisons to other available streamlined freshwater genomes revealed that the CL500-11 genome contained a disproportionate number of cell wall/capsule biosynthesis genes and the most diverse spectrum of genes involved in the uptake of dissolved organic matter (DOM) substrates, particularly peptides.In situexpression patterns indicated the importance of DOM uptake and protein/peptide turnover, as well as type I and type II carbon monoxide dehydrogenase and flagellar motility. Its location in the water column influenced its gene expression patterns the most. We observed increased bacteriorhodopsin gene expression and a response to oxidative stress in surface waters compared to its response in deep waters. While CL500-11 carries multiple adaptations to an oligotrophic lifestyle, its investment in motility, its large cell size, and its distribution in both oligotrophic and mesotrophic lakes indicate its ability to thrive under conditions where resources are more plentiful. Our data indicate that CL500-11 plays an important role in nitrogen-rich DOM mineralization in the extensive deep-lake hypolimnion habitat.

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