Quality assurance of diatom counts in Europe: towards harmonized datasets

Investigations on organism ecology, biodiversity and biogeography often use large compiled datasets to extract information on species ecological preferences, which then can be used in environmental assessment. Freshwater benthic diatoms are commonly used in this context. However, it is important that the taxonomic information of the separate diatom datasets is compatible. At present, inconsistencies between diatom datasets, mainly due to differences and uncertainties in diatom identification, may misinform diatom taxon-specific ecological preferences, geographical distribution and water quality assessment. It is our opinion that these inconsistencies in diatom datasets can be reduced with quality assurance (QA), such as identification exercises. However, the results of these exercises must be well documented and well communicated; otherwise, gained knowledge may not spread inter-regionally or internationally. As a first step to reach greater consistency in QA/harmonization studies, this article (1) presents and compares information of existing diatom identification and counting QA from published and grey (non-peer reviewed) European literature to identify advantages and drawbacks of each approach; (2) summarizes taxa that can easily be misidentified according to European identification exercises; and (3) suggests a consistent design of identification exercises for diatom dataset QA

Siseveekogud : õpik kõrgkoolidele

Inimeste kõige tavalisemad seosed siseveekogudega on matkamine, kalapüük, suplemine, janu kustutamine ja taimede kastmine. Et veekogude ääres viibimine mõjub paljudele rahustavalt, on jõgedel-järvedel miljonivaadete kaudu kindel koht ka kinnisvaraäris. Veekogudeta ei saa läbi sportlased (purjetajad, sõudjad ja motohuvilised). Leidub selliseidki indiviide, keda meelitavad mittesöödavad või koguni palja silmaga nähtamatud vee-elanikud. Eesti on väike madal maa, millel on pikk mererand, aga kus leidub ka palju siseveekogusid. Eriline on kahe suure järve – Peipsi ja Võrtsjärve – asumine lähestikku. Seisuvete pindala osakaalu järgi kogu riigi pindalast on Eesti Euroopas pärast Soomet ja Rootsit koos Norraga kolmandal-neljandal kohal. Eesti ja tema ümbrus on puhta veega seni niisiis hästi varustatud, kuid see rikkus ühtlasi kohustab veekogusid heaperemehelikult ja jätkusuutlikult majandama. Ka Eestis on muresid nii veevarude, veekogude kui nende seisundiga. Sisevete uurimine on Eestis kestnud juba üle 100 aasta. Seda on süstemaatiliselt korraldanud nii Looduseuurijate Selts, Tartu Riiklik Ülikool, Teaduste Akadeemia kui Maaülikool. Suurte järvede kõrval pole unustatud väikesi järvi ega vooluveekogusid. Uurida vee ja veekogude omadusi, arendada ja kasvatada nende spetsialiste ongi mõistlik seal, kus on, mida tundma õppida. Üha enam leitakse seoseid looduslike ja inimtekkeliste mõjurite ning ökosüsteemide vastuste vahel. Ühtlasi ühendatakse neid seoseid sotsiaalmajanduslike küsimuste ja looduskaitsega. Eesti siseveekogude kohta on peale arvukate ja enamasti võõrkeelsete teadusartiklite ilmunud ka eestikeelseid raamatuid. Siin neist väike loetelu: väikejärved (Eesti järved, 1968; Mäemets, 1977; Laarmaa jt 2019); Võrtsjärv (1973, 2003); Peipsi (1999, 2008), vooluveed (Järvekülg jt 2001; Timm jt 2019). Kalaraamatuid esindavad Mikelsaar (1984) ning Hunt (2019), veetaimi „Eesti taimede määraja“ (2010). Silmaga nähtavate veeselgrootute ülevaate pakub Timm (2015). Ülevaatlikku eestikeelset õpikut siseveekogude ning nende talitlemise kohta seni polnud. Eesti ülikoolides on kõigil kolmel õppetasandil (bakalaureuse-, magistri- ja doktoriõpe) õppekavasid, kus vajatakse teadmisi siseveekogudest. Võõrkeelseid eeskujusid leidub päris mitu, kuid need käsitlevad enamasti kas ainult hüdrobioloogiat või limnoloogiat. Esimene on elustiku-, teine keskkonna-alase suunitlusega. Uus õpik sisaldab mõlemaid ning sobib loodetavasti paljudele loodusteaduslikele ja looduskaitselistele kursustele, eriti bakalaureusetasemel. Õpik koosneb kolmest suurest alajaotusest: (1) siseveekogude füüsikalis-keemiline iseloomustus, levik ja teke; (2) elupaigad veekogudes, olulised elustikurühmad ning nendevahelised suhted; (3) siseveekogude majandamine, kaitse ja tervendamine. Peamiselt vaadeldakse Eesti siseveekogusid, aga seda kogu maailma taustal. Koostajad loodavad, et raamat annab lugejatele nii vastuseid küsimustele kui ka süvendab huvi sisevete kui kaunite, põnevate ning inimestele eluliselt oluliste loodusobjektide suhtes.Õpik on valminud riikliku programmi „Eestikeelsete kõrgkooliõpikute koostamine ja väljaandmine (2008–2012)“ raames ning Eesti Maaülikooli ja Sihtasutuse Archimedes osalisel toel

A comparison of national approaches to setting ecological status boundaries in phytobenthos assessment for the European Water Framework Directive: results of an intercalibration exercise

The European Union (EU)'s Water Framework Directive (WFD) requires that all Member States participate in intercalibration exercises in order to ensure that ecological status concepts and assessment levels are consistent across the EU. This paper describes one such exercise, performed by the countries in the Central/Baltic Geographical Intercalibration Group stretching from Ireland in the west to Estonia in the east and from the southern parts of Scandinavia to the northern regions of Spain and Italy (but excluding alpine regions, which were intercalibrated separately). In this exercise, methods used to measure ecological status of rivers using benthic diatoms were compared. Ecological status is estimated as the ratio between the observed value of a biological element and the value expected in the absence of significant human impact. Approaches to defining the 'reference sites', from which these 'expected' values were derived, varied from country to country. Minimum criteria were established as part of the exercise but there was still considerable variation between national reference values, reflecting typological differences that could not be resolved during the exercise. A simple multimetric index was developed to compare boundary values using two widely used diatom metrics. Boundary values for high/good status and good/moderate status set by each participant were converted to their equivalent values of this intercalibration metric using linear regression. Variation of ±0.05 EQR units around the median value was considered to be acceptable and the exercise provided a means for those Member States who fell significantly above or below this line to review their approaches and, if necessary, adjust their boundaries

Global Patterns and Controls of Nutrient Immobilization On Decomposing Cellulose In Riverine Ecosystems

Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low-nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing climate. Nonetheless, environmental controls on immobilization are poorly understood because rates are also influenced by plant litter chemistry, which is coupled to the same environmental factors. Here we used a standardized, low-nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates. In rivers, P immobilization rates were controlled by surface water phosphate concentrations, but N immobilization rates were not related to inorganic N. The N:P of immobilized nutrients was tightly constrained to a molar ratio of 10:1 despite wide variation in surface water N:P. Immobilization rates were temperature-dependent in riparian zones but not related to temperature in rivers. However, in rivers nutrient supply ultimately controlled whether microbes could achieve the maximum expected decomposition rate at a given temperature

Phosphorus in Estonian soils, surface waters and lake sediments : [presentation]

Presentation at the 11th International Shallow Lakes Conference, Estonia 11.-16.06.2023.We acknowledge the Estonian Research Council grants PRG709 and PRG1167, also European Union's Horizon 2020 research and innovation programme (project TREICLAKE) under grant agreement No 951963 for providing financial support for the project.We acknowledge the Estonian Research Council grants PRG709 and PRG1167, also European Union's Horizon 2020 research and innovation programme (project TREICLAKE) under grant agreement No 951963 for providing financial support for the project

Changes in particulate organic matter passing through a large shallow lowland lake

Different sources of particulate organic matter (POM) as well as its composition affect the biological food web and hence the self-purification potential and water quality of rivers. We studied the effect of a large shallow lake on the POM pool of the water passing through it. Over four years, we analysed monthly the amount and composition of POM and a set of environmental variables in the inflows and in the outflow of Lake Võrtsjärv (Estonia). In the inflows, the live pool of POM consisted of phytoplankton – small crypto-, dino-, and chlorophytes. The concentration of chlorophyll a (Chl a), as a proxy of phytoplankton biomass, was positively correlated with temperature and total phosphorus and negatively with dissolved silica, total nitrogen, and discharge. In the outflow, the share of the live component of POM was much larger than in the inflows but was also dominated by phytoplankton represented by grazing resistant filamentous cyanobacteria. Chl a was positively correlated with total phosphorus, temperature, pH, and precipitation, and negatively with dissolved silica, total nitrogen, and discharge in the outflow. The different amounts, composition, and seasonal dynamics of POM in the inflows and in the outflow have potentially substantial impacts on the food web with a predominating classical pathway in the inflows versus a detrital pathway in the outflow.This study was supported by the institutional research funding (IUT 21-2) of the Estonian Ministry of Education and Research and by the MARS project ‘Managing Aquatic Ecosystems and Water Resources under Multiple Stress’ funded under the 7th EU Framework Programme, Theme 6 ‘Environment including climate change’ (Contract No. 603378). We are grateful to Dr. Jonne Kotta and to the two anonymous reviewers for valuable comments on the manuscript. Mrs Ester Jaigma kindly revised the English text of the manuscript. The publication costs of this article were covered by the Estonian Academy of Sciences.This study was supported by the institutional research funding (IUT 21-2) of the Estonian Ministry of Education and Research and by the MARS project ‘Managing Aquatic Ecosystems and Water Resources under Multiple Stress’ funded under the 7th EU Framework Programme, Theme 6 ‘Environment including climate change’ (Contract No. 603378). We are grateful to Dr. Jonne Kotta and to the two anonymous reviewers for valuable comments on the manuscript. Mrs Ester Jaigma kindly revised the English text of the manuscript. The publication costs of this article were covered by the Estonian Academy of Sciences

Defining reference conditions for coastal areas in the Baltic Sea

The overall aim of DEFINE is to provide a methodology to define reference conditions for nutrient concentrations in the coastal zone of the Baltic Sea. This will aid the national authorities that surround the Baltic basin in implementing the EU's Water Framework Directive (WFD) by providing decision-makers with a methodology to assess reference conditions and the degree of past and present departure from this state, such that appropriate policy and management measures can be taken at national and European levels. DEFINE adopts a palaeoecological approach grounded on diatom-based transfer functions, which can then be applied to define background total nitrogen (TN) concentrations in estuaries and coastal areas over the entire Baltic Sea. All transfer functions and necessary supporting documentation will be publicly available as a coherent management tool and accessible via the MOLTEN/DEFINE web page (http://craticula.ncl.ac.uk/Molten/jsp/)

Järvede seisundi parandamiseks vajalike uuringute teostamine ja meetmekavade väljatöötamine : projekti lõpparuanne : Pullijärve meetme- ja tegevuskava

Euroopa Liidu Veepoliitika Raamdirektiiv (VRD) reguleerib vee kasutamise ja selle hea seisundi säilitamisega seotud seaduseid ning regulatsioone liikmesriikides. Vesi on hindamatu ressurss, mistõttu nõuab dokument liikmesriikidelt pingutusi ja tegevusi, et saavutada pinnavete hea keemiline ja ökoloogiline seisund. Pullijärv1 on pehme ja heleda veega eutrofeerunud oligotroofne järv ning siin elavad mitmed haruldased looduskaitsealused liigid. Lisaks on järv olulise rekreatsioonilise väärtusega kohalike seas. Viimaste uuringute käigus on järve ökoloogiline seisund olnud kesine ja mitmed kvaliteedinäitajad on oluliselt halvenenud. Seetõttu on vajalik uurida “mittehea” seisundi põhjuseid ja töötada välja tõhusad meetmed järve seisundi parandamiseks. Eesti Maaülikool esitas Keskkonnainvesteeringute Keskuse (KIK) poolt läbiviidud taotlusvooru projekti nr 14705 “Järvede seisundi parandamiseks vajalike uuringute teostamine ja meetmekavade väljatöötamine” taotluse, mis rahastati pooles mahus. Läbirääkimiste tulemusel kooskõlastati uus lähteülesanne Keskkonnaameti poolt 28.09.2018. a (nr 7-18/18/3808-6). Uus lähteülesanne keskendub Pullijärve (VEE2155200) mittehea seisundi põhjuste väljaselgitamisele. Uuringute käigus selgitati olemasolevate andmete alusel Pullijärve seisundi dünaamikat alates 1950. aastatest tänapäevani, uuriti sise- ja väliskoormust ning pakuti välja meetmed järve seisundi parandamiseks. Uurimismeetodid, mida kasutati hüdrokeemilistel analüüsidel ja elustiku uuringutel, on standardiseeritud või interkalibreeritud ja vastavad seadustes äratoodud nõuetele ning nendega on võimalik tutvuda põhjalikumalt töö metoodika peatükkides. Parameetrite seisundi klassipiirid pärinevad keskkonnaministri määrusest nr 44 (Pinnaveekogumite…, 2009). Töö eesmärk on välja töötada meetme- ja tegevuskava Pullijärve hea ökoloogilise seisundi saavutamiseks järgmise veemajanduskava perioodi jooksul (2020-2027). Uuringu lõpparuanne koosneb kahest osast: Esimeses osas (järve seisundi dünaamika) antakse ülevaade Pullijärve funktsioneerimisest ja kvaliteedielementide dünaamikast. Esitatakse välis- ja sisekoormuse uuringute tulemused. Teises osas (meetme- ja tegevuskava) kirjeldatakse kliima mõju pehme- ja heledaveelisele järvele, antakse ülevaade ökosüsteemiteenustest ning pakutakse välja meetme- ja tegevuskava koos ajakavaga. Uuringut viisid läbi ja aruande koostasid Eesti Maaülikooli Põllumajandus- ja keskkonnainstituudi Hüdrobioloogia ja kalanduse õppetooli teadlased: prof. Ingmar Ott, Ph.D. (vastutav täitja), M.Sc. Ronald Laarmaa, M.Sc. Kairi Maileht, Ph.D. Sirje Vilbaste, Ph.D. Margot Sepp, M.Sc. Katrin Saar, Ph.D Henn Timm, M.Sc. Anu Palm ja Katrin Ott

Quality assurance of diatom counts in Europe: towards harmonized datasets

Investigations on organism ecology, biodiversity and biogeography often use large compiled datasets to extract information on species ecological preferences, which then can be used in environmental assessment. Freshwater benthic diatoms are commonly used in this context. However, it is important that the taxonomic information of the separate diatom datasets is compatible. At present, inconsistencies between diatom datasets, mainly due to differences and uncertainties in diatom identification, may misinform diatom taxon-specific ecological preferences, geographical distribution and water quality assessment. It is our opinion that these inconsistencies in diatom datasets can be reduced with quality assurance (QA), such as identification exercises. However, the results of these exercises must be well documented and well communicated; otherwise, gained knowledge may not spread inter-regionally or internationally. As a first step to reach greater consistency in QA/harmonization studies, this article (1) presents and compares information of existing diatom identification and counting QA from published and grey (non-peer reviewed) European literature to identify advantages and drawbacks of each approach; (2) summarizes taxa that can easily be misidentified according to European identification exercises; and (3) suggests a consistent design of identification exercises for diatom dataset QA