{"refrec":{"BRefID":259565,"RR":"<b>Stehouwer, P.P.</b> (2016). Effects of various ballast water treatment methods on the survival of phytoplankton and bacteria. University of Groningen: Groningen. ISBN 9789036788083. 100 pp. <a href=\"http://hdl.handle.net/11370/fa2f67d2-a223-4846-b922-a136ceb9955c\" target=\"_blank\">hdl.handle.net/11370/fa2f67d2-a223-4846-b922-a136ceb9955c</a>","BEntID":251576,"PublicFlag":1,"CheckedFlag":0,"wosflag":null,"vabbflag":null,"RefStringPartII":". PhD Thesis. University of Groningen: Groningen. ISBN 9789036788083. 100 pp. <a href=\"http://hdl.handle.net/11370/fa2f67d2-a223-4846-b922-a136ceb9955c\" target=\"_blank\">http://hdl.handle.net/11370/fa2f67d2-a223-4846-b922-a136ceb9955c</a>","DocTypID":5,"DocType":"Book/Monograph","MarineFlag":0,"FreshFlag":0,"BrackishFlag":0,"TerrestrialFlag":0,"Authorstring":"Stehouwer, P.P.","OrigTitleTranslFlag":0,"Authorstringtrunc":"Stehouwer, P.P.","Englishabstract":"Aquatic invasive species are among the worst threats to marine biodiversity. The main vector for the spread of these aquatic invasive species is ships’ ballast water. Because of this, the International Maritime Organization (IMO) adopted the Ballast Water Convention. Part of this convention is the D-2 ballast water performance standard, which sets limits to the amount of viable organisms allowed to be in ballast water upon discharge. The limits of the D-2 standard are: 1. less than 10 viable organisms/m3 in the size class =50 µm; 2. less than 10 viable organisms/mL in the size class =10 - <50 µm; 3. limits on the abundance of toxigenic Vibrio cholera, Escherichia coli and intestinal enterococci. In order to meet this standard, manufacturers developed different types of Ballast Water Treatment Systems (BWTSs). These BWTSs need to be approved according to IMO regulations by an independent party. Several approval tests were performed at the Royal Netherlands Institute of Sea Research (NIOZ). The focus of this thesis was to test the effects of various ballast water treatment methods on the survival of phytoplankton and bacteria. Different methods are used to reduce the numerical abundance of organisms, most notably Ultraviolet-radiation (UV) and ‘active substances’ (chemicals). Both treatment methods were considered in this thesis. To measure the efficacy of different BWTSs, methods had to be developed that are applicable to all types of treatments. The standard IMO regulations state that treated ballast water has to be stored in the dark in simulated ballast water tanks for five days before being tested against the D-2 standard. However, it was questionable if this time period would be sufficient to account for delayed effects of the disinfectant and possible recovery of organisms. In other words, it was not known if re-growth of micro-organisms could occur after this standardized five day period. Therefore, in the present thesis, the possibility of re-growth was examined by executing long term incubation experiments under light-dark conditions simulating the post-discharge situation in the open sea. Phytoplankton and bacterial abundance, composition and diversity were monitored by a range of analytical techniques, including classical microscopy, flow cytometry and molecular fingerprinting. In a first series of experiments, UV and chlorine dioxide (CD) treated water was incubated for 20 days under favorable conditions with respect to irradiance and nutrient availability to stimulate the growth of micro-organisms that had survived the treatment. After both treatments, re-growth of phytoplankton occurred (Chapter 2). This suggests that currently approved BWTSs meet the IMO D-2 standard, but do not completely eliminate the potential spread of aquatic organisms through ballast water. To identify the species that re-grew after ballast water treatment, UV treated samples were incubated and monitored for phytoplankton abundance and species composition. Microscopy showed that ballast water treatment changed the species composition and that certain species were more likely to re-grow after treatment (Chapter 3). However, microscopy was not always able to identify the exact species. Because of this the application of flow cytometry, microscopy and DNA-sequencing as methods of species identification were investigated. Flow cytometry provided fast quantification of phytoplankton, but could only provide a rough indication of phytoplankton diversity. Microscopy provided a more qualitative method of identification, but could not always identify the phytoplankton to the species level. DNA-sequencing provided accurate species identification but proved to be time-consuming and only identified one or two of the most dominant species in the sample. The most common re-growing species after UV treatment proved to be Thalassiosira weissflogii. This indicates that some species are more likely to survive ballast water93treatment than others and that ballast water treatment may apply selective force to create resistant species (Chapter 4). In the follow-up experiment, phytoplankton re-growth was monitored in six BWTSs; three systems were based on UV, two based on electrochlorination (EC) and one based on chlorine dioxide (CD). All BWTSs incubation experiments were performed for 20 days with treated ballast water, during which growth, photosynthetic efficiency and phytoplankton species composition were followed. The three UV systems all showed the same pattern after the initial UV exposure, notably a gradual decrease in phytoplankton abundances followed by re-growth. Treatments using 200 % or 400 % of the normal UV dose reduced phytoplankton numbers more strongly, but did not prevent their re-growth. Results of EC and CD BWTSs were comparable to each other. However, UV and active substance-based treatment systems showed significantly different responses. Both types of systems showed an immediate reduction in phytoplankton photosynthetic efficiency. However, for UV treatment systems phytoplankton abundances decreased over several days while for chlorine-based treatment systems the drop in phytoplankton abundance was immediate. The species composition of re-growing phytoplankton also differed between UV and EC treatment. Overall, all BWTSs reduced phytoplankton abundances to below the values of the D-2 standard, which represents a reduced risk of future aquatic invasions through ballast water. However, all (but one) re-growing species were smaller than 10 µm, which means they are not covered by the D-2 standard (Chapter 5). To assess possible environmental risks associated with BWTSs that use ‘active substances’, a BWTS that uses a chemical mixture known as Peraclean® Ocean (PO) was evaluated. The residual of PO is acetate that might be present in concentrations exceeding 100 mg/L in discharged ballast water. To study the potential environmental impact of PO, microbial dynamics and acetate degradation were measured during incubation of discharge water following PO treatment. In addition, microbial dynamics and acetate degradation were studied at different temperatures in dark microcosms that simulated enclosed ballast water tanks. After about nine days bacteria abundances greatly increase in PO treated waters to almost ten times of initial control abundances. Furthermore, bacterial diversity was also altered by the changes in water chemistry. Breakdown of acetate occurred faster at higher temperatures. At the lowest temperatures almost no acetate breakdown occurred, but even at the highest temperature the acetate pool was not depleted. This implies that not all acetate will be broken down in ballast water tanks, even during long voyages in warm waters. It was concluded from this study that regular discharge of acetate-containing ballast water in harbors and bays may stimulate growth of heterotrophic bacteria, causing oxygen depletion and changes in the microbial community, especially in colder regions (Chapter 6). The D-2 standard does not consider total heterotrophic bacterial abundances. Increases in bacterial abundance as shown for this BWTS are allowed under current IMO regulations. The potential harmful effects on the ecosystem presented by the discharge of bacteria-rich ballast water demonstrate the necessity to include total heterotrophic bacteria in the D-2 standard. In conclusion, the present thesis has revealed two major shortcomings in the ballast water regulations and particularly in the D-2 standard. It is recommended that the D-2 standard is amended to include limit values for viable phytoplankton and zooplankton organisms < 10 µm as well as total heterotrophic bacteria.","AbstractOtherLang":"Aquatische invasieve soorten vormen een van de grootste bedreigingen voor de mariene biodiversiteit. De voornaamste bron van verspreiding van deze aquatische invasieve soorten is het ballastwater van schepen. Dit is de reden dat de Internationale Maritieme Organisatie (IMO) de Ballast Water Conventie aannam. Een onderdeel van de conventie is de zogenaamde D-2 ballast water prestatie standaard, die grenzen stelt aan het aantal organismen in het ballastwater bij lozing. De grenzen van de D-2 standaard zijn: 1. minder dan 10 organismen/m3 in de grootteklasse =50 µm; 2. minder dan 10 organismen/mL in de grootteklasse =10 - <50 µm; 3. vaststelling van maximaal toelaatbare concentraties van toxigene Vibrio cholerae, Escherichia coli en intestinale Enterococci. Om aan deze standaard te voldoen moeten schepen uitgerust worden met een ballastwater behandelingssysteem (BWBS). Deze BWBS moeten getest worden volgens de IMO regels door een onafhankelijk testinstituut. Een aantal van deze tests is uitgevoerd bij het Koninklijk Nederlands Instituut voor Onderzoek der Zee (NIOZ). Het doel van dit proefschrift is om de effecten van verschillende BWBS op het overleven van phytoplankton en bacterien te testen. Verschillende behandelingsmethoden worden toegepast om de aantallen organismen te reduceren. De meest gebruikte behandelingsmethoden zijn blootstelling aan Ultraviolette straling (UV) en ‘actieve substanties’ (chemicaliën). Om de efficientie van deze verschillende behandelingsmethoden nauwkeuring te bepalen zijn tests nodig die bij ieder type behandeling werken. Volgens de IMO regels moet behandeld ballastwater vijf dagen in een donkere gesimuleerde ballastwatertank opgeslagen worden voordat getest word of het water aan de D-2 standaard voldoet. Het is echter niet duidelijk of deze vijf dagen voldoende zijn om te testen voor vertraagde effecten van de disinfectie methode en mogelijk herstel van de organismen. Kort samengevat, het was niet bekend of organismen zich weer zouden kunnen gaan vermenigvuldigen (vanaf hier hergroei genoemd) na deze periode van vijf dagen. Daarom werd in dit proefschrift het punt hergroei onderzocht aan de hand van incubatie experimenten onder licht-donker condities. Fytoplankton- en bacterie-aantallen, samenstelling en diversiteit werden gecontroleerd met verschillende analytische methoden, waaronder microscopie, flow cytometrie en genetische analyse. In een eerste serie experimenten werd water dat met UV of chloordioxide (CD) behandeld was 20 dagen onder gunstige condities qua licht en nutriënten geïncubeerd om de groei van micro-organismen die de behandeling overleefd hadden te stimuleren. Bij beide behandelingen vond hergroei van phytoplankton plaats (Hoofdstuk 2). Dit betekent dat zelfs wanneer BWBS-en aan de IMO D-2 standaard voldoen, dit niet betekent dat er geen risico meer is van verspreiding van aquatische organismen via ballastwater. Om de soorten te identificeren die na behandeling hergroeien werden UV-behandelde ballastwater monsters geïncubeerd en de fytoplankton aantallen en soortensamenstelling gevolgd. Met behulp van microscopie werd duidelijk dat ballastwater behandeling de soortensamenstelling verandert, daarnaast kwamen sommige soorten vaker terug na behandeling (Hoofdstuk 3). Omdat microscopie niet altijd de precieze soort kon identificeren werden flow cytometrie, microscopie en DNA-sequencing toegepast om te vergelijken welke methode het beste is voor de soortenidentificatie in ballastwater monsters. Flow cytometrie leverde snel fytoplankton aantallen, maar gaf slechts een ruwe indicatie van de soortensamenstelling. Microscopie leverde een meer kwalitatieve identificatiemethode, maar kon niet altijd tot op soortsniveau gaan. DNA-sequencing leverde een precieze identificatie op soortsniveau, maar bleek zeer tijdrovend en kon alleen de meest dominante soorten onderscheiden. De meest frequent hergroeiende soort na UV-95behandeling was Thalassiosira weissflogii. Dit wijst er op dat sommige soorten ballastwater behandeling beter kunnen overleven en dat ballastwaterbehandeling daardoor selectie-druk uit kan oefenen om resistente soorten te creëeren (Hoofdstuk 4). In het aansluitende experiment werd de fytoplankton hergroei van zes BWBS-en vergeleken; drie systemen gebruikten UV, twee gebruikten electrochlorinatie (EC) en een gebruikte CD. Bij alle BWBS werden 20 dagen incubatie experimenten met behandeld ballastwater uitgevoerd. Tijdens deze incubatie experimenten werd groei, fotosynthese-efficiëntie en fytoplankton soortensamenstelling gevolgd. De drie UV BWBS-en hadden allemaal hetzelfde patroon van geleidelijke afname in fytoplanktonaantallen na behandeling gevolgd door hergroei. Behandelingen met 200 % of 400 % van de normale UV dosis reduceerden fytoplanktonaantallen sterker, maar er vond nog steeds hergroei plaats. De resultaten van EC en CD waren vergelijkbaar met elkaar. Daarentegen waren de resultaten van BWBS-en op basis van UV en chemicaliën significant verschillend. Beide types BWBS reduceerden de fotosynthese-efficiëntie onmiddelijk, maar bij de UV BWBS-en namen de fytoplankton aantallen geleidelijk over meerdere dagen af terwijl bij actieve substantie BWBS de afname in fytoplankton aantallen onmiddelijk plaatsvond. De soortsamenstelling van hergroeiend fytoplankton verschilde ook tussen UV en chemicaliën BWBS-en. Alle geteste BWBS-en reduceerden plankton aantallen tot onder de D-2 standaard, wat een verminderd risico van toekomstige aquatische invasies impliceert. Echter, alle (op één na) hergroeiende soorten waren kleiner dan 10 µm, wat betekent dat ze niet onder de D-2 standaard vallen (Hoofdstuk 5). Om de mogelijke gevaren van BWBS die ‘actieve substanties’ gebruiken in te schatten werd een BWBS dat de chemische mix Peraclean® Ocean (PO) gebruikt geevalueerd. Het residu van PO is acetaat dat bij lozen in concentraties van meer dan 100 mg/L in het ballastwater kan voorkomen. Om de potentiële effecten van PO op het milieu te beoordelen werden microbiële dynamiek en acetaatafbraak tijdens incubatie van PO behandeld ballastwater gevolgd. Daarnaast werd de microbiële dynamiek en acetaat afbraak gevolgd bij verschillende temperaturen in donkere microcosmi die gesloten ballastwatertanks simuleerden. Na ongeveer negen dagen namen de bacterieconcentraties sterk toe in PO behandeld ballastwater, tot bijna 10 keer de beginwaarde van de controle. Daarnaast was de bacteriële diversiteit ook beïnvloed. De afbraak van acetaat was sneller bij hogere temperaturen. Bij de laagste temperaturen vond bijna geen afbraak van acetaat plaats, maar zelfs bij de hoogste temperaturen werd niet alle acetaat afgebroken binnen de duur van het experiment (20 dagen). Dit wijst er op dat niet alle acetaat in de ballastwater tanks afgebroken word, zelfs niet bij lange reizen in warm water. Dit betekent dat regelmatig lozen van acetaat-verrijkt ballastwater in havens en baaien eutrofiëring en veranderingen in de microbiële gemeenschap kan veroorzaken, vooral in koudere gebieden (Hoofdstuk 6). De D-2 standaard heeft geen grenzen voor heterotrofe bacterie-concentraties. Toenames in bacterieconcentraties zoals bij dit BWBS zijn toegestaan onder de huidige regelgeving. Echter, deze resultaten laten zien dat het nodig is om totale heterotrofe bacterien in de D-2 standaard op te nemen. Dit proefschrift brengt twee belangrijke tekortkomingen van de ballastwater regelgeving en vooral de D-2 standaard aan het licht. De D-2 standaard moet aangepast worden door het toevoegen van grenswaardes voor phytoplankton en zooplankton < 10 µm en totale heterotrofe bacteriën.","BibLvlCode":"M","StandardTitle":"Effects of various ballast water treatment methods on the survival of phytoplankton and bacteria","OrigTitleLangCode":"en","OrigTitleLangCodeExtended":"eng","OrigTitleLangID":15,"DateLastModified":{"date":"2024-12-10 01:33:17.368041","timezone_type":1,"timezone":"+01:00"},"UserAccessRight":null,"UserAccID":null,"AuthorKeywords":null,"OtherDescriptors":null,"Notes":null,"AnaPub":null,"MonPub":2016,"DateUpdate":"2016-07-05","DateCreate":"2016-07-05","SecASFANote":null,"ConfID":null,"PeerRev":0,"VlizCoreFlag":1,"WoScode":null,"VABBcode":null,"OpenAcc":1,"Handle":"11370/fa2f67d2-a223-4846-b922-a136ceb9955c"},"refs":null,"anarec":null,"monrec":{"MonID":259565,"ISBN":"9789036788083","PubliDate":2016,"IssueDate":null,"Volume":null,"Issue":null,"Pagination":"100","Place":"Groningen","Edition":null,"BRefXtra":null,"BRefXtraRR":null,"SerID":null,"SerRR":null,"Ser2BRefID":null,"Ser2RR":null,"StandardTitleSer":null,"ISSN":null,"AbbrevSer":null,"Degree":"PhD","ThesisID":259565,"InsID":null,"Acronym":null,"FullStandardName":null,"ToPubliDate":null,"SerNotes":null,"eISBN":null,"Pages":100},"serrec":null,"relations":null,"relationsRev":null,"addrec":null,"othpubs":null,"ownerships":null,"authors":[{"AutName":"Stehouwer","Firstname":"Peter","Initials":"P.P.","Affiliation":"EDS","Discriminator":null,"CorporateFlag":0,"BEntID":251576,"AutID":233509,"OrderNr":1,"DegrID":null,"EditorFlag":0,"CorrespFlag":0,"IllustratorFlag":0,"ReviserFlag":0,"TranslatorFlag":0,"InsAcronym":"EDS","InsFSN":"Koninklijk Nederlands Instituut voor Onderzoek der Zee; Estuarine and Delta Systems","ORCID":null,"PersID":29967,"InsID":13657}],"mapdetails":null,"datasets":null,"monographs":null,"monparts":null,"serparts":null,"BEntOpen":251576,"BEntPrivate":null,"availability":[{"BInstID":292819,"LibID":2779,"BRefID":259565,"EmbargoDate":null,"FullEmbargoDate":null,"PhysMedID":16,"hasOCRd":1,"ShelfLocCode":"292819","RFID":null,"PaidValue":null,"Medium":"Server","Description":null,"Acronym":null,"Library":"NIOZ","DutchTerm":null,"URL":null,"ClassifID":260,"Classification":"NIOZ Open Repository","ReqLink":null,"ClassifTypID":1,"URLLocation":"https://www.vliz.be/imisdocs/publications/","SubDir":1,"InternalReq":null,"LoggedInReq":null,"Disclaimer":"Disclaimer_NIOZ","DutchDisclaimer":null,"FileFormat":".pdf","FileDescr":"pdf","InsPub":1,"InsID":397,"FileFormID":6,"LendableFlag":null,"PublicFlag":1,"orderLib":"NIOZ","Notes":null,"AccConID":null,"AccessConstraint":null,"LicURL":null}],"litstyles":[{"LitStyID":7,"Style":"Dissertation"}],"thespers":[{"PersID":29210,"Surname":"Peperzak","Firstname":"Louis","Initials":"L.","Role":"Promotor"}],"arch2discl":805,"SERpubls":null,"MONpubls":null,"pictures":[],"thestermsPath":null,"thestermsASFA":null,"taxtermsASFA":null,"geotermsASFA":null,"collections":null,"conf":null,"proj":null,"Physdatasets":null,"spcols":{"805":{"SpName":"Koninklijk Nederlands Instituut voor Onderzoek der Zee","SpColID":805,"ParSpColID":null,"TopParID":null,"ShortName":"NIOZ","URLLocation":"https://www.vliz.be/imis/nioz/imis.php?refid=","LibID":2779,"OpenRepoFlag":1,"SpTypID":1,"TopParIDNotWebsite":null,"SpColPath":"NIOZ"}},"doi":null,"publs":[{"PublID":14465,"PublName":"University of Groningen","InsID":399,"PersID":null,"INBOID":10928,"OrderNr":1}],"serparttypes":null,"monauthors":null,"MParts":null,"SParts":null,"hLibs":null,"langs":[{"BEntID":251576,"AbstractFlag":0,"LangID":15,"LangCode":"en","Lang":"English","DutchTerm":"Engels","LangCodeExtended":"eng"},{"BEntID":251576,"AbstractFlag":1,"LangID":15,"LangCode":"en","Lang":"English","DutchTerm":"Engels","LangCodeExtended":"eng"}],"urls":[{"URL":"http://hdl.handle.net/11370/fa2f67d2-a223-4846-b922-a136ceb9955c","externalID":"11370/fa2f67d2-a223-4846-b922-a136ceb9955c","URLTypeCode":"Handle","URLID":49047,"URLTypID":32,"URLType":"Handle","URLPrefix":"https://hdl.handle.net/"}],"thesterms":null,"taxterms":null,"geoterms":null,"othterms":null,"asfacodes":null,"asfa2codes":null,"thestermsFRIS":null,"taxtermsFRIS":null,"geotermsFRIS":null,"othtermsFRIS":null,"resmessage":"","complete":1,"sessions":{"newSesName":"Leonne.van.der.Weegen@nioz.nl","newSesDate":{"date":"2016-07-05 14:05:55.070000","timezone_type":3,"timezone":"Europe/Brussels"},"updSesName":"Leonne.van.der.Weegen@nioz.nl","updSesDate":{"date":"2016-07-05 14:05:55.070000","timezone_type":3,"timezone":"Europe/Brussels"}}}