Ice algae resource utilization by benthic macro- and megafaunal communities on the Pacific Arctic shelf determined through lipid biomarker analysis

2020 ◽  
Vol 651 ◽  
pp. 23-43 ◽  
Author(s):  
CW Koch ◽  
LW Cooper ◽  
JM Grebmeier ◽  
K Frey ◽  
TA Brown
Keyword(s):  
Organic Carbon ◽  
Sea Ice ◽  
Feeding Strategy ◽  
Food Sources ◽  
Ice Algae ◽  
Surface Deposit ◽  
Suspension Feeders ◽  
Deposit Feeders ◽  
Lipid Biomarker ◽  
Biomarker Analysis

We studied ice algae utilization by benthic fauna from the northern Bering and Chukchi Seas using highly branched isoprenoid (HBI) biomarkers. We assessed whether various food acquisition strategies influence the observed HBI signatures. The proportion of phytoplankton to ice algae-sourced HBIs was determined through the H-Print approach that is presumed to reflect the percentage of sea ice organic carbon (iPOC) incorporated into tissues, relative to phytoplankton organic carbon. Cluster analysis separated 3 groups based on location and feeding strategy that were significantly influenced by annual sea ice persistence. Ice algae utilization was most significant in the northeast Chukchi Sea, where seasonal sea ice was present the longest. General feeding strategy was determined to be a significant factor in the degree of ice algae utilization. Predominant deposit feeders (both surface and subsurface) used more ice algae relative to suspension feeders. Organic carbon incorporated by predominant suspension feeders was primarily phytoplankton-based. The vast majority of all organisms sampled (~90%) incorporated a measurable quantity of iPOC. Sipunculids and brittle stars had the highest relative dependence on ice algae, while other taxa displayed plastic dietary responses, including the suspension/surface deposit feeder Macoma calcarea. This study indicates that ice algae are widely utilized in Pacific Arctic benthic food webs, but most benthic organisms displayed flexibility in consuming the available food sources. The elevated utilization of ice algae by deposit feeders may prove to be a disadvantage for these organisms if they cannot adapt to the ongoing decline of iPOC as seasonal sea ice declines.

scholarly journals Organic carbon characteristics in yedoma and thermokarst deposits on Baldwin Peninsula, West-Alaska

2018 ◽  
Author(s):  
Loeka L. Jongejans ◽  
Jens Strauss ◽  
Josefine Lenz ◽  
Francien Peterse ◽  
Kai Mangelsdorf ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Lake Sediments ◽  
Lake Basin ◽  
Study Region ◽  
Thermokarst Lake ◽  
Discontinuous Permafrost ◽  
Lipid Biomarker ◽  
Biomarker Analysis ◽  
Thawing Permafrost

Abstract. As Arctic warming continues and permafrost thaws, more soil and sedimentary organic carbon (OC) will be decomposed in northern high latitudes. Still, uncertainties remain in the quantity and quality of OC stored in different deposit types of permafrost landscapes. This study presents OC data from deep permafrost and lake deposits on the Baldwin Peninsula which is located in the southern portion of the continuous permafrost zone in West Alaska. Sediment samples from yedoma and drained thermokarst lake basin (DTLB) deposits as well as thermokarst lake sediments were analyzed for cryostratigraphical and biogeochemical parameters and their lipid biomarker composition to identify the size and quality of belowground OC pools in ice-rich permafrost on Baldwin Peninsula. We provide the first detailed characterization of yedoma deposits on Baldwin Peninsula. We show that three quarters of soil organic carbon in the frozen deposits of the study region (total of 68 Mt) is stored in DTLB deposits (52 Mt) and one quarter in the frozen yedoma deposits (16 Mt). The lake sediments contain a relatively small OC pool (4 Mt), but have the highest volumetric OC content (93 kg/m3) compared to the DTLB (35 kg/m3) and yedoma deposits (8 kg/m3), largely due to differences in the ground ice content. The biomarker analysis indicates that the OC in both yedoma and DTLB deposits is mainly of terrestrial origin. Nevertheless, the relatively high carbon preference index of plant leaf waxes in combination with a lack of degradation trend with depth in the yedoma deposits indicates that OC stored in yedoma is less degraded than that stored in DTLB deposits. This suggests that OC in yedoma has a higher potential for decomposition upon thaw, despite the relatively small size of this pool. These findings highlight the importance of molecular OC analysis for determining the potential future greenhouse gas emissions from thawing permafrost, especially because this area close to the discontinuous permafrost boundary is projected to thaw substantially within the 21st century.

Quantification of biomarkers as an estimation of soil organic matter turnover and sources under a crop rotation

2021 ◽  
Author(s):  
Layla M. San-Emeterio ◽  
Ian D. Bull ◽  
Jens Holtvoeth ◽  
Rafael López ◽  
Francisco J. González-Vila ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Crop Rotation ◽  
Total Lipid ◽  
C3 Plant ◽  
Organic Matter Turnover ◽  
Lipid Biomarker ◽  
Biomarker Analysis ◽  
The Impact

<p>Lipid biomarker analysis is an efficient tool for tracing organic matter sources in diverse environments. The quantification of biomarkers facilitates the location of soil organic carbon (SOC) from different sources in a soil profile. According to their structure, biomarkers from total lipid extracts (TLE) would exhibit different degrees of susceptibility to degradation, affecting thus their preservation in soils. Hence, it is crucial to better identify these biomarkers according to diverse stability scales. The aim of this study is to assess SOC contributions from aboveground and to develop a wider approach based on the allocation of C to quantitatively assess the sources of organic matter in low SOM content, highly weathered Mediterranean soils, following a C3-C4 rotation experiment.</p><p>Soil samples were taken from three depth intervals (0-5, 5-20, 20-40 cm) from a Mediterranean agricultural soil at “La Hampa” experimental station used for a crop rotation experiment with wheat (C3 plant) and maize (C4 plant). Lipids were extracted and quantified as described in [1].</p><p>The total lipid extracts were dominated by a homologous series of n-alkanols (saturated alcohols), short-, mid- and long-chain fatty acid methyl ester (FAME), branched FAME, unsaturated (mono- and polyunsaturated) FAME and sterols. Short-chain FAME, monounsaturated FAME were the most abundant fractions of free lipids. Mono-unsaturated alkanoic acids (Cn:1 FA) were detected in considerable amounts in all samples, namely various isomers of C16:1, C18:1, C20:1 and C22:1; these are believed to be mainly synthesised by soil bacteria. A significant increase of these compounds in rotation plots leads to an effective microbial consumption of labile organic matter in the surface soil [2]. Regarding FAME, the observed chain lengths ranged from C13 to C32, showing a unimodal distribution maximising at C16 and C18. These compounds are attributed also to microbial products, supporting our findings from the high proportion of the monounsaturated compounds found. In general, and in relation with all compounds, the abundances increased up to 20% compared with the control plots representing the initial content.</p><p>These results indicate that, only after three years of crop rotation, a considerable contribution of soil organic carbon is inherited from bacterial activity. The combination of extractable lipids has been shown to validate the use of TLE as a proxy for source and other information on vegetation change and soil processes. This work will bring a discussion on the use of these compounds for tracing the impact of crop rotation on carbon storage.</p><p>Acknowledgement: Ministerio de Ciencia Innovación y Universidades (MICIU) for INTERCARBON project (CGL2016-78937-R). L. San Emeterio also thanks MICIU for funding FPI research grants (BES-2017-07968). Mrs Desiré Monis is acknowledged for technical assistance.</p><p>[1] M. San-Emeterio, L., Bull, I. D., Holtvoeth, J., and González-Pérez, J. A.: Compound-specific isotopic analysis of fatty acids in three soil profiles to estimate organic matter turnover in agricultural soils., <em>EGU General Assembly 2020</em>, Online, 4–8 May 2020, EGU2020-18526, https://doi.org/10.5194/egusphere-egu2020-18526, 2020.</p><p>[2] Tu, T. T. N., Egasse, C., Anquetil, C., Zanetti, F., Zeller, B., Huon, S., & Derenne, S. (2017). Leaf lipid degradation in soils and surface sediments: A litterbag experiment. <em>Organic Geochemistry</em>, 104, 35-41.</p>

scholarly journals Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255686
Author(s):  
Chelsea W. Koch ◽  
Lee W. Cooper ◽  
Ryan J. Woodland ◽  
Jacqueline M. Grebmeier ◽  
Karen E. Frey ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sea Ice ◽  
Nitrogen Isotopes ◽  
Chukchi Sea ◽  
Trophic Position ◽  
Ice Algae ◽  
Pacific Walrus ◽  
Odobenus Rosmarus Divergens ◽  
Odobenus Rosmarus ◽  
The Pacific

The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus (Odobenus rosmarus divergens). The ability to track the trophic transfer of iPOC is critical to understanding its value in the food web, but prior methods have lacked the required source specificity. We analyzed the H-Print index, based on biomarkers of ice algae versus phytoplankton contributions to organic carbon in marine predators, in Pacific walrus livers collected in 2012, 2014 and 2016 from the Northern Bering Sea (NBS) and Chukchi Sea. We paired these measurements with stable nitrogen isotopes (δ15N) to estimate trophic position. We observed differences in the contribution of iPOC in Pacific walrus diet between regions, sexes, and age classes. Specifically, the contribution of iPOC to the diet of Pacific walruses was higher in the Chukchi Sea (52%) compared to the NBS (30%). This regional difference is consistent with longer annual sea ice persistence in the Chukchi Sea. Within the NBS, the contribution of iPOC to walrus spring diet was higher in females (~45%) compared to males (~30%) for each year (p < 0.001), likely due to specific foraging behavior of females to support energetic demands associated with pregnancy and lactation. Within the Chukchi Sea, the iPOC contribution was similar between males and females, yet higher in juveniles than in adults. Despite differences in the origin of organic carbon fueling the system (sea ice versus pelagic derived carbon), the trophic position of adult female Pacific walruses was similar between the NBS and Chukchi Sea (3.2 and 3.5, respectively), supporting similar diets (i.e. clams). Given the higher quality of organic carbon from ice algae, the retreat of seasonal sea ice in recent decades may create an additional vulnerability for female and juvenile Pacific walruses and should be considered in management of the species.

Macrophyte-derived detritus in shallow coastal waters contributes to suspended particulate organic matter and increases growth rates of Mytilus edulis

2020 ◽  
Vol 644 ◽  
pp. 91-103
Author(s):  
D Bearham ◽  
MA Vanderklift ◽  
RA Downie ◽  
DP Thomson ◽  
LA Clementson
Keyword(s):  
Organic Matter ◽  
Mytilus Edulis ◽  
Particulate Organic Matter ◽  
Coastal Waters ◽  
Gill Tissue ◽  
Suspension Feeder ◽  
Food Sources ◽  
Suspension Feeders ◽  
Blue Mussels ◽  
Suspended Particulate

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.

scholarly journals Analyses of depositional environments of the Marcellus formation in New York using biomarker and trace metal proxies

2021 ◽  
Author(s):  
Reilly M. Blocho ◽  
Richard W. Smith ◽  
Mark R. Noll
Keyword(s):  
Fatty Acids ◽  
New York ◽  
Organic Matter ◽  
New York State ◽  
Depositional Environments ◽  
Average Chain Length ◽  
Lipid Biomarker ◽  
Two Samples ◽  
Biomarker Analysis ◽  
Marcellus Formation

AbstractThe purpose of this study was to observe how the composition of organic matter (OM) and the extent of anoxia during deposition within the Marcellus Formation in New York varied by distance from the sediment source in eastern New York. Lipid biomarkers (n-alkanes and fatty acids) in the extractable organic component (bitumen) of the shale samples were analyzed, and proxies such as the average chain length (ACL), aquatic to terrestrial ratio (ATR) and carbon preference index (CPI) of n-alkanes were calculated. Fatty acids were relatively non-abundant due to the age of the shale bed, but n-alkane distributions revealed that the primary component of the OM was terrigenous plants. The presence of shorter n-alkane chain lengths in the samples indicated that there was also a minor component of phytoplankton and algal (marine) sourced OM. Whole rock analyses were also conducted, and cerium anomalies were calculated as a proxy for anoxia. All samples had a negative anomaly value, indicating anoxic conditions during deposition. Two samples, however, contained values close to zero and thus were determined to have suboxic conditions. Anoxia and total organic matter (TOM) did not show any spatial trends across the basin, which may be caused by varying depths within the basin during deposition. A correlation between nickel concentrations and TOM was observed and indicates that algae was the primary source of the marine OM, which supports the lipid biomarker analysis. It was determined that the kerogen type of the Marcellus Formation in New York State is type III, consistent with a methane-forming shale bed.

scholarly journals Microbial signature lipid biomarker analysis - an approach that is still preferred, even amid various method modifications

2015 ◽  
Vol 118 (6) ◽  
pp. 1251-1263 ◽  
Author(s):  
C. Willers ◽  
P.J. Jansen van Rensburg ◽  
S. Claassens
Keyword(s):  
Lipid Biomarker ◽  
Biomarker Analysis

scholarly journals Windows in Arctic sea ice: Light transmission and ice algae in a refrozen lead

2017 ◽  
Vol 122 (6) ◽  
pp. 1486-1505 ◽  
Author(s):  
Hanna M. Kauko ◽  
Torbjørn Taskjelle ◽  
Philipp Assmy ◽  
Alexey K. Pavlov ◽  
C. J. Mundy ◽  
...  
Keyword(s):  
Sea Ice ◽  
Light Transmission ◽  
Arctic Sea Ice ◽  
Ice Algae ◽  
Arctic Sea

scholarly journals The impact of dissolved organic carbon and bacterial respiration on pCO2 in experimental sea ice

2016 ◽  
Vol 141 ◽  
pp. 153-167 ◽  
Author(s):  
J. Zhou ◽  
M. Kotovitch ◽  
H. Kaartokallio ◽  
S. Moreau ◽  
J.-L. Tison ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sea Ice ◽  
Dissolved Organic Carbon ◽  
Bacterial Respiration ◽  
The Impact

scholarly journals Micrometer scale imaging of sedimentary climate archives – Sample preparation for combined elemental and lipid biomarker analysis

2019 ◽  
Vol 127 ◽  
pp. 81-91 ◽  
Author(s):  
Susanne Alfken ◽  
Lars Wörmer ◽  
Julius S. Lipp ◽  
Jenny Wendt ◽  
Heidi Taubner ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Lipid Biomarker ◽  
Biomarker Analysis ◽  
Micrometer Scale

scholarly journals Opportunistic feeding on various organic food sources by the cold-water coral <i>Lophelia pertusa</i>

2014 ◽  
Vol 11 (1) ◽  
pp. 123-133 ◽  
Author(s):  
C. E. Mueller ◽  
A. I. Larsson ◽  
B. Veuger ◽  
J. J. Middelburg ◽  
D. van Oevelen
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
De Novo ◽  
Cold Water ◽  
Feeding Strategy ◽  
Food Sources ◽  
Coral Tissue ◽  
Lophelia Pertusa ◽  
Opportunistic Feeding ◽  
Water Coral

Abstract. The ability of the cold-water coral Lophelia pertusa to exploit different food sources was investigated under standardized conditions in a flume. The tested food sources, dissolved organic matter (DOM, added as dissolved free amino acids), bacteria, algae, and zooplankton (Artemia) were deliberately enriched in 13C and 15N. The incorporation of 13C and 15N was traced into bulk tissue, fatty acids, hydrolysable amino acids, and the skeleton (13C only) of L. pertusa. Incorporation rates of carbon (ranging from 0.8–2.4 μg C g−1 DW d–1) and nitrogen (0.2–0.8 μg N g−1 DW d–1) into coral tissue did not differ significantly among food sources indicating an opportunistic feeding strategy. Although total food assimilation was comparable among sources, subsequent food processing was dependent on the type of food source ingested and recovery of assimilated C in tissue compounds ranged from 17% (algae) to 35% (Artemia). De novo synthesis of individual fatty acids by L. pertusa occurred in all treatments as indicated by the 13C enrichment of individual phospholipid-derived fatty acids (PLFAs) in the coral that were absent in the added food sources. This indicates that the coral might be less dependent on its diet as a source of specific fatty acids than expected, with direct consequences for the interpretation of in situ observations on coral nutrition based on lipid profiles.

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