Methyl mercury in zooplankton—the role of size, habitat, and food quality

2002 ◽  
Vol 59 (10) ◽  
pp. 1606-1615 ◽  
Author(s):  
Martin Kainz ◽  
Marc Lucotte ◽  
Christopher C Parrish
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Body Size ◽  
Methyl Mercury ◽  
Size Fraction ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Bacterial Food

Pathways of methyl mercury (MeHg) accumulation in zooplankton include ingestion of organic matter (OM). We analyzed fatty acid (FA) biomarkers in zooplankton to (i) investigate the effect of allochthonous and autochthonous OM ingestion on MeHg concentrations ([MeHg]) in zooplankton and (ii) examine how algal and bacterial food sources affect MeHg bioaccumulation. We partitioned bulk zooplankton samples (i.e., >500, 202, 100, and 53 μm) from Lake Lusignan (Québec) and measured [MeHg] and [FA] in each fraction. [MeHg] increased with increasing body size and was significantly higher in pelagic than in littoral macrozooplankton (>500 μm). The amount of the ingested terrestrial FA biomarker 24:0 indicated that less than 1% of the total FA in zooplankton was derived from allochthonous sources. More than 60% of the ingested FA originated from algal biomarkers and <10% from bacterial biomarkers. Relative amounts of algal-derived essential FA and bacterial FA were not associated with [MeHg] in any size fraction. In pelagic zones, the amount of MeHg in zooplankton related positively to the number of large organisms such as Calanoid copepods and Daphnia. We propose that the accumulation of MeHg in lacustrine zooplankton depends on the zooplankton habitat rather than on the quality of ingested food.

scholarly journals Fixation and redistribution of arsenic during early and late diagenesis in the organic matter-rich members of the Lockatong Formation, Newark basin, USA: implication for the quality of groundwater

2017 ◽  
Vol 53 ◽  
pp. 253-268 ◽  
Author(s):  
Larbi Rddad
Keyword(s):  
Trace Elements ◽  
Organic Matter ◽  
Black Shale ◽  
Anoxic Conditions ◽  
Arsenic In Groundwater ◽  
Late Diagenesis ◽  
Rock Eval ◽  
Newark Basin

The Byram and Walls Island members in the lower and upper sections, respectively, of the Lockatong Formation in the Newark basin near the border between Pennsylvania and New Jersey were chosen to assess (i) the role of euxinic/anoxic conditions in sequestering arsenic (As) and other trace elements and (ii) the redistribution of these elements during catagenetic transformations. ἀese members are rich in organic matter and host pyrite which occurs as disseminations, small patches, and subparallel veins. ἀe sulfur isotope values of pyrite samples range between -7.5 and 0.5 ‰CDT (average = -3.5‰CDT). ἀe negative δ34S values are indicative of Bacterial Sulfate Reduction (BSR) under low temperature and euxinic/anoxic conditions. ἀe total organic carbon (TOC) values in this member ᴀuctuate between 0.5 and 2.1%. ἀese euxinic/anoxic conditions enhanced the incorporation of As and other trace elements in both organic matter and pyrite. ἀe As concentrations range from 13 to 800 mg/kg and from 1.4 to 34 mg/kg in pyrite and black shale samples, respectively. Rock Eval analyses reveal that organic matter is over-mature which altered the correlation between TOC and As. ἀe thermal cracking of organic matter resulted in the removal of these elements from organic matter and their subsequent incorporation in pyrite and bitumen. Organic matter- and pyrite-rich anoxic black shale layers and bitumen veins are potential sources of arsenic in groundwater in the Newark basin, with arsenic values that reach up to 215 μg/L.

scholarly journals Preliminary studies on some waste vegetable contribution to the soil fertility

2013 ◽  
Vol 24 (2) ◽  
pp. 127-130
Author(s):  
Elisabeta Chirila ◽  
Naliana Lupascu ◽  
Simona Raicu
Keyword(s):  
Organic Matter ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Vegetable Waste ◽  
Fruit Waste ◽  
Before And After ◽  
Vegetable Wastes ◽  
Nitrogen Phosphorus

Abstract Researches on the use of waste vegetable (tomatoes, peppers) and fruits (apples, plums) in order to improve the nutritional quality of the soil have been performed. The content in nitrogen, phosphorus, potassium, humus, organic matter have been analyzed in fruits and vegetable waste and also in soil before and after mixing with each waste at a ratio of 1:2.5. Analyses were done by using current analytical methods (chemical and absorption molecular spectrometry) after previous mineralization of samples with appropriate reagents. To investigate the effect of vegetable wastes on the plants growth, wheat has been planted in the witness soil sample and in the mixed soil with wastes. The nutrients concentration in vegetable waste was higher than in fruit waste (33-75%). Available phosphorus concentration increased about two times in soil with fruit waste while in the soil with vegetable the increase was of about 3 times. Potassium concentration increased about three times in soil mixed with both types of waste. Although potassium and organic matter have higher values in the soil amended with fruit waste than in the witness soil, the height of the wheat was similar with those in the control soil due to the limiting role of phosphorus.

scholarly journals Aplikasi Pemupukan Organik dan Hayati di Sawah Kabupaten Tasikmalaya Jawa Barat

2019 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Reginawanti Hindersah ◽  
Sondi Kuswaryan
Keyword(s):  
Organic Matter ◽  
Community Service ◽  
Paddy Soil ◽  
Group Discussion ◽  
Paddy Fields ◽  
Plant Production ◽  
Basic Knowledge ◽  
Extension Program

ABSTRAKSebagian sawah di  Kecamatan Sukaratu, Kabupaten Tasikmalaya tertimbun material letusan Gunung Galunggung pada 1982 sehingga kualitas sawah tidak sebaik sebelum letusan. Peningkatan kualitas tanah sawah dapat dilakukan dengan bahan organik dan pupuk hayati. Tujuan Pengabdian kepada Masyarakat ini adalah memberikan pengetahuan dasar tentang pupuk hayati kepada petani di desa Sinagar dan Linggajati serta meningkatkan keterampilan petani dalam aplikasi pupuk hayati disertai kompos. Untuk mencapai tujuan tersebut, telah dilakukan diskusi kelompok terfokus dan penyuluhan mengenai pupuk hayati, praktek pembuatan kompos dan apliksi pupuk hayati konsorsium di sawah. Hasil kegiatan ini adalah 20 orang petani memahami  peran mikroba dan pupuk kotoran ternak serta komps dalam produksi tanaman; tetapi  mereka belum mampu membuat pupuk organik sesuai standard. Hanya satu orang petani yang mengaplikasikan pupuk hayati disertai penambahan kompos di tanah sawah sehingga meningkatkan produksi sebesar 1%.  Program ini memberikan gambaran bahwa teknologi pupuk hayati dapat diadopsi oleh petani di Kecamatan Sukaratu.Kata kunci: bahan Organik;  kotoran ternak; padi sawah; pupuk hayati.ABSTRACTSome of the paddy fields in Sukaratu Sub-district, Tasikmalaya Regency were buried by Mount Galunggung's eruption material in 1982 so that the quality of soil was worse than that before the eruption. Improving the quality of paddy soil can be established with biological fertilizers. The purpose of this community service was to introduce the basic knowledge about biofertilizer to farmers in the Sinagar and Linggajati Village; and to improve farmers' skills in the application of biological fertilizers and compost. To achieve the goals, we conducted a focused group discussion, short extension program on biological fertilizers, compost production, and consortium biofertilizer application in paddy fields. The result verified that 20 farmers has knowledge about the role of beneficial microbes, manure and compost for plant production but they did not able to prepare standardized organic matter. However one farmer was interested to apply biofertilizers along with compost to paddy fields. This program illustrates that biofertilizer technology can be adopted by farmer in Sukaratu Sub-district.Key Words: biofertilizer; cattle manure; organic matter; paddy soil

scholarly journals Trophic diversity of seagrass detritus copepods: A consequence of species-specific specialization or a random diet?

2016 ◽  
Author(s):  
Thibaud Mascart ◽  
Marleen De Troch ◽  
François Remy ◽  
Loïc Michel ◽  
Gilles Lepoint
Keyword(s):  
Organic Matter ◽  
Trophic Ecology ◽  
Harpacticoid Copepod ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Copepod Community ◽  
Suspended Organic Matter ◽  
Trophic Diversity ◽  
Seagrass Meadows ◽  
Species Specific

One of the major ecological research questions is understanding how biodiversity influences ecosystem functioning. Unravelling interspecific feeding preferences of organisms with overlapping trophic niches will give part of the answer. Subsequently, the present study displays the trophic diversity of a benthic copepod community in a North-Western Corsican Posidonia oceanica seagrass ecosystem. These seagrass meadows are often interrupted by bare sand patches serving as deposition area for loose detritus. The accumulated macrophytodetritus, mainly derived from senescent macrophytes, harbour a diverse community of Harpacticoida (Crustacea, Copepoda). The most abundant copepods (i.e. three harpacticoids and one calanoid, belonging to different eco-morphological types) and their potential food sources (i.e. macrophytodetritus, epiphytic biofilm and suspended organic matter) were analysed for stable isotope ratios (δ13C, δ15N) and total lipids content. The results revealed a harpacticoid copepod feeding preference towards the epiphytic biofilm, while calanoid copepods preferred suspended organic matter. Additionally, a species-specific composition variation revealed finer partitioning of food resources (e.g. different micro-organisms present in the biofilm like bacteria, diatoms, fungi) over time.In conclusion, results showed species-specific food preferences, resulting in trophic niche and resource partitioning. Every eco-morphological type seems to cope in different ways with temporal fluctuations of food sources to comply with their nutritional needs. This illustrates the high resilience of the copepod community present in macrophytodetritus accumulations. Moreover, our results underlined the importance of multiple biomarker species-specific analysis in trophic ecology studies, especially in complex and dynamic environments offering numerous food items to consumers.

scholarly journals Assimilation of shrimp farm sediment by Holothuria scabra: a coupled fatty acid and stable isotope approach

2020 ◽  
Vol 33 ◽  
pp. 3
Author(s):  
Margaux Mathieu-Resuge ◽  
Fabienne Le Grand ◽  
Gauthier Schaal ◽  
Edouard Kraffe ◽  
Anne Lorrain ◽  
...  
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Stable Isotope ◽  
Fish Meal ◽  
Shrimp Farming ◽  
Food Sources ◽  
Alternative Source ◽  
Additional Food ◽  
Integrated Aquaculture ◽  
Holothuria Scabra

Deposit-feeding sea cucumbers are efficient nutrient recyclers and have the potential to contribute to the limitation of organic matter load in polyculture or integrated aquaculture systems. Assessing how they assimilate organic matter originating from other farmed species is therefore important for the development of such multi-species farming systems. Here, a coupled stable isotope − fatty acid approach was used to characterize the assimilation of organic matter from shrimp (Penaeus stylirostris) farming by Holothuria scabra in an experimental culture system. H. scabra were reared in mesocosms on shrimp farming-originating sediment with and without additional food sources (maize and fish meals). Although fatty acid results did indicate that shrimp-farming sediment was assimilated by holothurids, we found no evidence of maize waste and fish meal contribution to H. scabra organic carbon (no effect on δ13C, no accumulation of meal-specific fatty acids). However, a strong effect of fish meal on H. scabra δ15N was observed, suggesting that this additional food source could represent an alternative source of nitrogen for holothurids. Finally, this study supports the culture of H. scabra as a perspective to reduce sedimentary organic matter excess associated with shrimp farms, and suggest that the addition of selected food sources might contribute to increasing the content in some nitrogen organic compounds in holothurid tissues.

scholarly journals The quality of dissolved organic matter shapes the biogeography of the active bathypelagic microbiome

2021 ◽  
Author(s):  
Marta Sebastian ◽  
Pablo Sanchez ◽  
Guillem Salazar ◽  
Xose A Alvarez-Salgado ◽  
Isabel Reche ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Environmental Changes ◽  
Large Fraction ◽  
Free Living ◽  
Lower Growth ◽  
Differential Abundance ◽  
Differential Abundance Analysis

The bathypelagic ocean (1000-4000 m depth) is the largest aquatic biome on Earth but it is still largely unexplored. Due to its prevalent low dissolved organic carbon concentrations, most of the prokaryotic metabolic activity is assumed to be associated to particles. The role of free-living prokaryotes has thus been mostly ignored, except that of some chemolithoautotrophic lineages. Here we used a global bathypelagic survey of size-fractionated metagenomic and 16S (genes and transcripts) data and performed a differential abundance analysis to explore the functional traits of the different prokaryotic life-strategies, their contribution to the active microbiome, and the role that the quality of the dissolved organic matter (DOM) plays in driving this contribution. We found that free-living prokaryotes have limited capacity to uplift their metabolism in response to environmental changes and display comparatively lower growth rates than particle associated prokaryotes, but are responsible for the synthesis of vitamins in the bathypelagic. Furthermore, their contribution to the active prokaryotic microbiome increased towards waters depleted of labile DOM, which represented a large fraction of the tropical and subtropical ocean sampled stations. This points to a relevant yet overlooked role of free-living prokaryotes in DOM cycling in the vast bathypelagic desert.

scholarly journals Separate Feeding Between the Pelagic Stage of the Squat Lobster Munida gregaria and the Larger Sized Zooplankton Crustacean Groups in the Beagle Channel as Revealed by Stable Isotopes

2021 ◽  
Vol 8 ◽  
Author(s):  
Leonardo R. Castro ◽  
Humberto E. González ◽  
José Garcés-Vargas ◽  
Pamela Barrientos
Keyword(s):  
Organic Matter ◽  
Body Size ◽  
Vertical Distribution ◽  
Water Column ◽  
Food Sources ◽  
Isotopic Niche ◽  
Squat Lobster ◽  
Beagle Channel ◽  
Winter Conditions ◽  
Pelagic Stage

In southern Patagonia, the Beagle Channel shows very low production during winter but simultaneously sustains very dense aggregations of the pelagic stage of squat lobster (Munida gregaria), a benthic decapod whose pelagic juveniles have the largest body size within the chitinous pelagic community. To assess the coexistence of the mesozooplankton community and the pelagic M. gregaria stage under the harsh feeding winter conditions, we conducted a research cruise at two locations connected to the Beagle Channel, Yendegaia Bay (land terminating-glacier) and Pia Fjord (marine-terminating glacier). Our results showed that the zooplankton communities were similar in these two fjords, that a single pelagic group dominated in terms of biomass (pelagic Munida gregaria), and that differences in vertical distribution existed between most of the principal crustacean zooplankton and pelagic M. gregaria. All groups showed consumption of terrestrially derived organic matter, as revealed by their δ13C values. However, the isotopic composition, trophic positions (TP), and isotopic niche areas of the groups separated pelagic M. gregaria, presenting some of the lowest δ15N and the highest δ13C values, and the narrowest isotopic niche width. Pelagic M. gregaria was dominated by a single body size class along the 0–100 m water column, with no diel changes in vertical distribution, remained mostly in the upper layers (0–50 m), and benefited from the slightly higher phytoplankton concentrations at shallower depths as revealed by their higher δ13C values and low trophic position. In contrast, the other groups, including zoea M. gregaria stages, developed changes in distribution between day and night or remained deeper in the water column. These groups showed higher δ15N values, higher TP, and lower δ13C values, most of which probably fed on a nanoheterotrophs and terrestrial particulate organic matter mixture at deeper layers. Thus, the different vertical distributions, different trophic level food sources, and slightly different organic carbon sources apparently reduced any potential competence for food resources and form part of the feeding strategy that may facilitate the coexistence of the different large pelagic crustaceans under harsh feeding winter conditions in this high latitude austral region.

scholarly journals Trophic diversity of seagrass detritus copepods: A consequence of species-specific specialization or a random diet?

2016 ◽  
Author(s):  
Thibaud Mascart ◽  
Marleen De Troch ◽  
François Remy ◽  
Loïc Michel ◽  
Gilles Lepoint
Keyword(s):  
Organic Matter ◽  
Trophic Ecology ◽  
Harpacticoid Copepod ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Copepod Community ◽  
Suspended Organic Matter ◽  
Trophic Diversity ◽  
Seagrass Meadows ◽  
Species Specific

One of the major ecological research questions is understanding how biodiversity influences ecosystem functioning. Unravelling interspecific feeding preferences of organisms with overlapping trophic niches will give part of the answer. Subsequently, the present study displays the trophic diversity of a benthic copepod community in a North-Western Corsican Posidonia oceanica seagrass ecosystem. These seagrass meadows are often interrupted by bare sand patches serving as deposition area for loose detritus. The accumulated macrophytodetritus, mainly derived from senescent macrophytes, harbour a diverse community of Harpacticoida (Crustacea, Copepoda). The most abundant copepods (i.e. three harpacticoids and one calanoid, belonging to different eco-morphological types) and their potential food sources (i.e. macrophytodetritus, epiphytic biofilm and suspended organic matter) were analysed for stable isotope ratios (δ13C, δ15N) and total lipids content. The results revealed a harpacticoid copepod feeding preference towards the epiphytic biofilm, while calanoid copepods preferred suspended organic matter. Additionally, a species-specific composition variation revealed finer partitioning of food resources (e.g. different micro-organisms present in the biofilm like bacteria, diatoms, fungi) over time.In conclusion, results showed species-specific food preferences, resulting in trophic niche and resource partitioning. Every eco-morphological type seems to cope in different ways with temporal fluctuations of food sources to comply with their nutritional needs. This illustrates the high resilience of the copepod community present in macrophytodetritus accumulations. Moreover, our results underlined the importance of multiple biomarker species-specific analysis in trophic ecology studies, especially in complex and dynamic environments offering numerous food items to consumers.

Cognitive Health Counseling 40+

2013 ◽  
Vol 21 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Anne Eschen ◽  
Franzisca Zehnder ◽  
Mike Martin
Keyword(s):  
Outcome Variable ◽  
Pilot Phase ◽  
Subjective Memory ◽  
Cognitive Health ◽  
Health Counseling ◽  
Agents Of Change ◽  
Main Outcome Variable ◽  
Further Development

This article introduces Cognitive Health Counseling 40+ (CH.CO40+), an individualized intervention that is conceptually based on the orchestration model of quality-of-life management ( Martin & Kliegel, 2010 ) and aims at improving satisfaction with cognitive health in adults aged 40 years and older. We describe the theoretically deduced characteristics of CH.CO40+, its target group, its multifactorial nature, its individualization, the application of subjective and objective measures, the role of participants as agents of change, and the rationale for choosing participants’ satisfaction with their cognitive health as main outcome variable. A pilot phase with 15 middle-aged and six older adults suggests that CH.CO40+ attracts, and may be particularly suitable for, subjective memory complainers. Implications of the pilot data for the further development of the intervention are discussed.

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