Carbon gas fluxes from boreal aquatic sediments

The carbon dioxide (CO2) and methane (CH4) fluxes from aquatic sediments have recently received considerable interest because of the role of these gases in enhancing climate warming. CO2 is the main end product of aerobic respiration and CH4 is produced in large amounts under anaerobic conditions. Shallow, vegetated sediments are an important source of both gases. CH4 may be transported via rhizomes and aerenchymal tissues of aquatic plants from the sediment to the atmosphere, thus avoiding oxidation in the aerated sediment surface and water column. Temperature is known to be a key factor affecting benthic CO2 and CH4 flux rates, but the interplay between other factors that may affect the fluxes from sediments is still poorly known. In order to study the spatial and temporal variability of carbon gas fluxes in boreal aquatic sediments, the area-based CO2 production rates in lake and brackish water sediments and CH4 emissions in vegetated lake littorals were measured in this work. The effects of temperature, sediment quality, plant species, zoobenthos and seasonal variation on flux rates were also estimated. The range of CO2 production rates measured in the field was 0.1–12.0 mg C m–2 h–1 and that of CH4 emission rates 0–14.3 mg C m–2 h–1. When incubated at elevated temperatures (up to 30 °C) in the laboratory, the CO2 production rates increased up to 70 mg C m–2 h–1. Temperature explained 70–94% of the temporal variation in the CO2 production in lake sites and 51% in a brackish water site. In the lake mesocosm, temperature explained 50–90% of the variation of CH4 emission. By contrast, CH4 oxidation rate was not dependent on temperature. The CH4 fluxes through the plants of six emergent and floating-leaved plant species were studied in the field (temperature range 20.4–24.9 °C). Stands of the emergent macrophyte Phragmites australis emitted the largest amounts of CH4 (mean emission 13.9 ± 4.0 (SD) mg C m-2 h–1), the mean emission rate being correlated with mean net primary production (NPP) and mean solar radiation. In the stands of floating-leaved Nuphar lutea the mean CH4 efflux (0.5 ± 0.1 (SD) mg C m–2 h–1) was negatively correlated with mean fetch and positively with percentage cover of leaves on the water surface. On a regional level, stands of the emergents P. australis and Equisetum fluviatile emitted 32% more CH4 than natural open peatland during the growing season, although their areal coverage in the study region was only 41% of that of peatland area. Climate warming will presumably increase the carbon gas emission from vegetated littorals. The model-based estimated increase of CO2 production rate in June was 29% and for CH4 emissions as much as 65% for the time interval of 110 years from 1961–1990 to 2071–2100. The results indicate that carbon gas fluxes from aquatic sediments, especially from vegetated littorals, are significant at the landscape level. They are linked to temperature but also to several other interacting factors such as e.g. water and bottom quality and ecosystem composition. Detailed investigation of the overall links between the causes and effects is urgently needed in order to understand and predict the changes caused by warming climate

Suometsien hoidon tuet ja niiden ilmasto-, vesistö- ja biodiversiteettivaikutukset : Kestävän metsätalouden määräaikaisen rahoituslain (Kemera-lain) mukaisten tukien tarkastelu

Vuonna 2015 voimaan tulleen kestävän metsätalouden rahoituslain (KMRL 34/2015) voimassaoloa on ehdotettu jatkettavan vuodesta 2020 vuoden 2021 loppuun. Rahoituslain tavoitteena on ollut lisätä metsien kasvua ja ekologista kestävyyttä sekä hillitä vesistökuormitusta ja turvata monimuotoisuutta. Rahoituslain perusteella myönnettyjen julkisten tukien (noin 55 milj. euroa vuodessa) painopiste on suometsien osalta ollut selkeästi metsien kasvua lisäävissä toimenpiteissä. Tutkimus on tuottanut viime vuosina aikaisempaa tarkempaa tietoa suometsien aiheuttamasta vesistökuormituksesta ja niiden maaperän kasvihuonekaasupäästöistä. Tulosten mukaan ojitettujen suometsien merkitys vesistökuormitukselle on aiemmin luultua huomattavasti suurempi, ja suometsien maaperä on Suomen kasvihuonekaasuinventaariossa suuri päästölähde. Ojitetuilla suometsillä on luonnontilaisiin soihin verrattuna vähäinen merkitys monimuotoisuudelle. Nykyisellä rahoituslailla ja sen edeltäjillä on tuettu toimenpiteitä, joilla on uuden tutkimuksen mukaan haitallisia vaikutuksia ympäristöön. Suomi on sitoutunut päästövähennyksiin Pariisin ilmastosopimuksessa, ja tavoittelee viimeisessä hallitusohjelmassaan hiilensidonnan vahvistamista maankäyttösektorilla, vesistöpäästöjen pienentämistä ja luonnon monimuotoisuuden turvaamista. Tämän selvityksen tavoitteena on taustoittaa nykymuotoisen tukijärjestelmän ympäristövaikutuksia siten, että se tukee uuden rahoituslain sekä muun suometsien hoitoa ja käyttöä koskevan oikeudellisen sääntelyn valmistelua. Selvitys kuvaa suometsien hoidon tukijärjestelmää ja siihen osallistuvia toimijoita rooleineen, tarkastelee suometsille soveltuvien tukien ilmasto- (kasvihuonekaasut ja hiilen kierto), vesistö- ja monimuotoisuusvaikutuksia, ja ehdottaa ympäristön kannalta kestävämpiä suometsien hoito-, tuki- ja sääntelyvaihtoehtoja. Voimassa olevan rahoituslain mukaisista työlajeista suometsän hoidon tukeen liittyvä kunnostusojitus aiheuttaa lisääntyviä vesistö- ja kasvihuonekaasupäästöjä ja ylläpitää ojituksen aiheuttamaa monimuotoisuuden heikkenemistä. Metsänuudistamisen ja taimikonhoidon tuet kannustavat metsänomistajia tasaikäiseen metsänkasvatukseen. Tuettujen toimenpiteiden seurauksena suometsät päästävät ravinteita ja kiintoainesta vastaanottaviin vesistöihin, ja niiden maaperä on huomattava kasvihuonekaasujen päästölähde. Terveyslannoituksen tuen vaikutukset vesistö- ja kasvihuonekaasupäästöille ovat ainakin lyhyellä aikavälillä pieniä, mutta sen kriteerit on määritelty tasaikäisen metsänkasvatuksen perusteella. Nykyisen rahoitusjärjestelmän tuilla (metsäluonnon hoitohankkeiden tuki) voidaan myös ennallistaa soita, mikä on tehokas tapa palauttaa suon monimuotoisuutta, mutta tuen käyttö on jäänyt suhteellisen vähäiseksi. Tukia ja oikeudellista sääntelyä uudelleen suuntaamalla voidaan pienentää suometsien hoidon aiheuttamia ympäristövaikutuksia. Ympäristölle haitallisista tuista olisi luovuttava, ja niiden tilalle kehitettävä sellaisia tukia ja sääntelyä, joiden tavoitteena on vesistövaikutuksien ja monimuotoisuuden suojelun lisäksi myös suometsien hiilinielun vahvistaminen turpeen hävikkiä vähentämällä. Uuden tukijärjestelmän ja oikeudellisen sääntelyn ei tulisi kannustaa suometsien maaperän liialliseen kuivattamiseen, eikä niiden uudistamiseen tasaikäiseksi metsäksi. Havaitut ympäristövaikutukset puoltavat ennemminkin jatkuvapeitteisen, eri-ikäisrakenteisen metsänkasvatuksen käyttöä, mitä tukijärjestelmän ja muun sääntelyn tulisi edistää. Joidenkin suometsäkohteiden osalta tulisi harkita tukia ja sääntelyä, jotka mahdollistaisivat kevyemmän metsätalouden, ja jopa metsätaloudesta vähittäisen luopumisen. Suon aktiiviseen ennallistamiseen tulisi kannustaa monimuotoisuuden kannalta tärkeillä kohteilla. Tukijärjestelmää kehitettäessä on huomioitava suometsäalueiden vesitalouden näkökulma. Vesitalouteen vaikuttamisella on alueellisia heijastevaikutuksia kasvihuonekaasu- ja vesistöpäästöihin sekä monimuotoisuuteen. Alueellisella suunnittelulla voitaisiin saavuttaa suurempia kokonaishyötyjä vesitalouteen vaikuttavien tukien ja toimien sopivalla kohdentamisella. Myös tukien kohdistamiseen säädösten ja muiden tukiehtojen mukaisesti tulisi jatkossa kiinnittää aikaisempaa enemmän huomiota. Suomen metsäkeskuksen tarkastustulosten mukaan suometsän hoidon ja tuhkalannoituksen tukien osalta tässä on ollut ongelmia. Niiden seurauksena tukien myönteiset vaikutukset ovat usein jääneet tavoiteltua pienemmiksi ja vastaavasti haitalliset ympäristövaikutukset ovat voineet muodostua tarkoitettua suuremmiksi.202

Grey wolf genomic history reveals a dual ancestry of dogs

The grey wolf (Canis lupus) was the frst species to give rise to a domestic population, and they remained widespread throughout the last Ice Age when many other large mammal species went extinct. Little is known, however, about the history and possible extinction of past wolf populations or when and where the wolf progenitors of the present-day dog lineage (Canis familiaris) lived1–8 . Here we analysed 72 ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. We found that wolf populations were highly connected throughout the Late Pleistocene, with levels of diferentiation an order of magnitude lower than they are today. This population connectivity allowed us to detect natural selection across the time series, including rapid fxation of mutations in the gene IFT88 40,000–30,000 years ago. We show that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east. However, we also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, refecting either an independent domestication process or admixture from local wolves. None of the analysed ancient wolf genomes is a direct match for either of these dog ancestries, meaning that the exact progenitor populations remain to be located

Changes in parental smoking during pregnancy and risks of adverse birth outcomes and childhood overweight in Europe and North America : An individual participant data meta-analysis of 229,000 singleton births

Author summaryWhy was this study done? Maternal smoking during pregnancy is an important risk factor for various birth complications and childhood overweight. It is not clear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy. The associations of paternal smoking with birth and childhood outcomes also remain unknown. What did the researchers do and find? We conducted an individual participant data meta-analysis using data from 229,158 families from 28 pregnancy and birth cohorts from Europe and North America to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight. We observed that smoking in the first trimester only did not increase the risk of preterm birth and small size for gestational age but was associated with a higher risk of childhood overweight, as compared to nonsmoking. Reducing the number of cigarettes during pregnancy, without quitting, was still associated with higher risks of these adverse outcomes. Paternal smoking seems to be associated, independently of maternal smoking, with the risks of childhood overweight. What do these findings mean? Population strategies should focus on parental smoking prevention before or at the start of, rather than during, pregnancy. Future studies are needed to assess the specific associations of smoking in the preconception and childhood periods with offspring outcomes. Background Fetal smoke exposure is a common and key avoidable risk factor for birth complications and seems to influence later risk of overweight. It is unclear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy, or when only fathers smoke. We aimed to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight. Methods and findings We performed an individual participant data meta-analysis among 229,158 families from 28 pregnancy/birth cohorts from Europe and North America. All 28 cohorts had information on maternal smoking, and 16 also had information on paternal smoking. In total, 22 cohorts were population-based, with birth years ranging from 1991 to 2015. The mothers' median age was 30.0 years, and most mothers were medium or highly educated. We used multilevel binary logistic regression models adjusted for maternal and paternal sociodemographic and lifestyle-related characteristics. Compared with nonsmoking mothers, maternal first trimester smoking only was not associated with adverse birth outcomes but was associated with a higher risk of childhood overweight (odds ratio [OR] 1.17 [95% CI 1.02-1.35],Pvalue = 0.030). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08 [95% CI 1.02-1.15],Pvalue = 0.012), small size for gestational age (OR 2.15 [95% CI 2.07-2.23],Pvalue <0.001), and childhood overweight (OR 1.42 [95% CI 1.35-1.48],Pvalue <0.001). Mothers who reduced the number of cigarettes between the first and third trimester, without quitting, still had a higher risk of small size for gestational age. However, the corresponding risk estimates were smaller than for women who continued the same amount of cigarettes throughout pregnancy (OR 1.89 [95% CI 1.52-2.34] instead of OR 2.20 [95% CI 2.02-2.42] when reducing from 5-9 to = 10 to 5-9 andPeer reviewe

Grey wolf genomic history reveals a dual ancestry of dogs

The grey wolf (Canis lupus) was the first species to give rise to a domestic population, and they remained widespread throughout the last Ice Age when many other large mammal species went extinct. Little is known, however, about the history and possible extinction of past wolf populations or when and where the wolf progenitors of the present-day dog lineage (Canisfamiliaris) lived(1-8). Here we analysed 72 ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. We found that wolf populations were highly connected throughout the Late Pleistocene, with levels of differentiation an order of magnitude lower than they are today. This population connectivity allowed us to detect natural selection across the time series, including rapid fixation of mutations in the gene IFT8840,000-30,000 years ago. We show that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east. However, we also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, reflecting either an independent domestication process or admixture from local wolves. None of the analysed ancient wolf genomes is a direct match for either of these dog ancestries, meaning that the exact progenitor populations remain to be located.Peer reviewe

Origins and genetic legacy of prehistoric dogs

Dogs were the first domestic animal, but little is known about their population history and to what extent it was linked to humans. We sequenced 27 ancient dog genomes and found that all dogs share a common ancestry distinct from present-day wolves, with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow. By 11,000 years ago, at least five major ancestry lineages had diversified, demonstrating a deep genetic history of dogs during the Paleolithic. Coanalysis with human genomes reveals aspects of dog population history that mirror humans, including Levant-related ancestry in Africa and early agricultural Europe. Other aspects differ, including the impacts of steppe pastoralist expansions in West and East Eurasia and a near-complete turnover of Neolithic European dog ancestry

Biochar addition to agricultural soil increased CH4 uptake and water holding capacity - Results from a short-term pilot field study

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