Comparison of exposed and protected soft-bottom macrobenthic assemblages of the shallow sublittoral of Northern Portugal

Uni e sidade do Minho Escola de Ciências Ana Ca olina Cas o Cos a Compa ison o exposed and p o ec ed so - bo om mac oben hic assemblages o he shallow subli o al o No he n Po ugal ou ub o 2023 Ana Ca olina Cas o Cos a UMinho | 2023 Compa ison o exposed and p o ec ed so -bo om mac oben hic assemblages o he shallow subli o al o No he n Po ugal Uni e sidade do Minho Escola de Ciências Ana Ca olina Cas o Cos a ou ub o 2023 Compa ison o exposed and p o ec ed so -bo om mac oben hic assemblages o he shallow subli o al o No he n Po ugal UMinho | 2023 Uni e sidade do Minho Escola de Ciências Ana Ca olina Cas o Cos a Compa ison o exposed and p o ec ed so - bo om mac oben hic assemblages o he shallow subli o al o No he n Po ugal Disse ação de Mes ado Mes ado em Biodi e sidade, Ecologia e Al e ações Globais T abalho e e uado sob a o ien ação do(a) In es igado Diego Ca ei a Flo es In es igado Ma cos Rubal Ga cia ou ub o de 2023 ii DIREITOS DE AUTOR E CONDIÇÕES DE UTILIZAÇÃO DO TRABALHO POR TERCEIROS Es e é um abalho académico que pode se u ilizado po e cei os desde que espei adas as eg as e boas p á icas in e nacionalmen e acei es, no que conce ne aos di ei os de au o e di ei os conexos. Assim, o p esen e abalho pode se u ilizado nos e mos p e is os na licença abaixo indicada. Caso o u ilizado necessi e de pe missão pa a pode aze um uso do abalho em condições não p e is as no licenciamen o indicado, de e á con ac a o au o , a a és do Reposi ó iUM da Uni e sidade do Minho. A ibuição CC BY h ps://c ea i ecommons.o g/licenses/by/4.0/ iii Ag adecimen os Aos meus o ien ado es, Diego Ca ei a Flo es e Ma cos Rubal Ga cia, pela opo unidade de ealiza es e abalho sob a sua o ien ação, pelo conhecimen o ansmi ido, po oda a ajuda p es ada ao longo dos meses de abalho de labo a ó io e na esc i a des a disse ação, pela le eza com que me ajuda am a enca a os aspe os mais di íceis na ealização des e abalho, e po o na em odo es e p ocesso mais di e ido. A odos os que ize am pa e do meu pe cu so académico e semp e me mo i a am a aze melho , po odos os momen os de aleg ia que i emos e po es a em semp e disponí eis. À minha amiga Inês, pelos almoços no ja dim e no ege a iano, e pela companhia nos dias mais di íceis e soli á ios no labo a ó io. Ao Samuel, pela calma, paciência e con iança que me ansmi iu nos momen os de dú ida ao longo da execução des e abalho. À minha i mã, po oda a ajuda e po e semp e a pala a ce a nos momen os ce os. Po nunca me deixa desis i e po me mo i a semp e a segui os meus sonhos. Aos meus pais, po odo o es o ço, ca inho, dedicação e apoio incondicional que demons a am du an e odo es e pe cu so. Sem ocês nada dis o se ia possí el, ob igada po me incen i a em semp e a lu a pelo que gos o e a nunca desis i , po mui o di ícil que as coisas se o nem. A odos ós, o meu mais since o ob igado! i DECLARAÇÃO DE INTEGRIDADE Decla o e a uado com in eg idade na elabo ação do p esen e abalho académico e con i mo que não eco i à p á ica de plágio nem a qualque o ma de u ilização inde ida ou alsi icação de in o mações ou esul ados em nenhuma das e apas conducen e à sua elabo ação. Mais decla o que conheço e que espei ei o Código de Condu a É ica da Uni e sidade do Minho. Compa ação de comunidades mac oben ónicas dos undos sedimen a es da zona subli o al no No e de Po ugal Resumo Os undos sedimen a es são o maio ecossis ema do plane a, em á ea de cobe u a, e albe gam uma g ande di e sidade de o ganismos mac oben ónicos. As comunidades mac oben ónicas ap esen am um impo an e papel nos ecossis emas ma inhos, na eciclagem de nu ien es, decomposição de ma é ia o gânica, e nas condições do sedimen o. Apesa da sua ex ensão e impo ância, apenas uma pequena pe cen agem da sua comunidade mac oben ónica oi es udada, e mui as espécies con inuam po desc e e . Os p incipais a o es ísicos na de e minação da dis ibuição da auna mac oben ónica são: a ação das ondas, e as ca ac e ís icas do sedimen o, podendo es es se a e ados pela p esença de es u u as a i iciais de p o eção cos ei a. Es e es udo oi ealizado na zona cos ei a do No e de Po ugal, em Viana do Cas elo, em duas á eas: Baía de Co al, uma á ea p o egida pela p esença de um molhe, e em Cabedelo, uma á ea expos a à ação das ondas. Em cada á ea, o am amos ados ês locais escolhidos alea o iamen e, em ês da as di e en es. A auna mac oben ónica ecolhida nes as amos agens oi iden i icada, o am medidos pa âme os ambien ais, e calculados pa âme os como a di e sidade, iqueza de espécies e a abundância de indi íduos. Os esul ados mos a am di e enças signi ica i as en e os dois habi a s: na salinidade, iqueza de espécies e núme o de indi íduos. A análise PERMANOVA mos ou di e enças signi ica i as en e os habi a s, demons ando que as comunidades mac oben ónicas são di e en es, e a análise AMBI mos ou que a á ea p o egida ap esen a um maio g au de pe u bação do que a á ea expos a. Os esul ados ob idos ela i amen e à abundância e iqueza de mac oin e eb ados suge e que a es u u a das comunidades pode es a elacionada com os di e en es ecu sos disponí eis e com as condições hid odinâmicas e do sedimen o, sendo as úl imas al e adas pela p esença do molhe. Pala as-cha e: undos sedimen a es, es u u as a i iciais, molhe, comunidades mac oben ónicas, p o egido, expos o. i Compa ison o exposed and p o ec ed so -bo om mac oben hic assemblages o he shallow subli o al o No he n Po ugal Abs ac So -bo oms a e he la ges ecosys em on Ea h in a eal co e age and ha bo a wide di e si y o mac oben hic o ganisms. Mac oben hic auna plays a e y impo an ole in ma ine ecosys ems in nu ien cycling, decomposing o ganic ma e , and on he condi ions o he sedimen . Al hough so -bo oms a e he la ges ecosys em on ea h, only a small pe cen age o hei mac oben hic auna has been s udied and mos o i s species a e s ill undesc ibed. Two o he main physical ac o s a ec ing mac oben hic auna dis ibu ion a e wa e ac ion and sedimen cha ac e is ics, and hese can be changed by he p esence o a i icial p o ec ion s uc u es. This s udy was conduc ed on he No he n coas o Po ugal, in Viana do Cas elo, in wo a eas: Co al Bay, p o ec ed by a b eakwa e , and Cabedelo, which is exposed o wa e ac ion. In each a ea, h ee andom si es we e sampled on h ee di e en da es. The mac oben hic auna was la e iden i ied and en i onmen al pa ame e s, ichness, di e si y and abundance we e measu ed. The esul s showed signi ican di e ences in salini y, species ichness and numbe o indi iduals be ween he wo habi a s. PERMANOVA analysis showed signi ican di e ences be ween he habi a s, showing he assemblages a e di e en , and AMBI analysis showed ha he p o ec ed habi a was mo e dis u bed han he exposed one. The pa e ns o abundance and ichness o mac oin e eb a es sugges ha assemblage’s s uc u e may be ela ed o di e en esou ces a ailable, sedimen and hyd odynamic cha ac e is ics, ha a e al e ed by he p esence o he b eakwa e . Keywo ds: so -bo oms, a i icial s uc u es, b eakwa e , mac oben hic assemblages, p o ec ed, exposed. ii Index Ag adecimen os ............................................................................................................... iii Resumo .............................................................................................................................. Abs ac ............................................................................................................................ i Lis o Figu es .................................................................................................................. ix Lis o ables ...................................................................................................................... x 1. In oduc ion .............................................................................................................. 2 1.1. Coas al zones ............................................................................................................ 2 1.2. Po uguese coas cha ac e is ics ................................................................................ 4 1.3. So -bo oms .............................................................................................................. 5 1.4. Mac oben hic auna ................................................................................................... 6 1.5. An h opogenic p essu es ........................................................................................... 8 1.6. Goals ........................................................................................................................ 9 2. Ma e ial and Me hods ............................................................................................ 12 2.1. S udy a ea............................................................................................................... 12 2.2. Sampling design ...................................................................................................... 13 2.3. Sample p ocessing .................................................................................................. 15 2.4. S a is ical analysis ................................................................................................... 16 2.5. AMBI (AZTI’s Ma ine Bio ic Index) ............................................................................ 18 3. Resul s ..................................................................................................................... 20 3.1. En i onmen al pa ame e s ....................................................................................... 20 3.1.1. Salini y ........................................................................................................ 20 3.1.2. G anulome y .............................................................................................. 21 3.2. Richness, di e si y and abundance .......................................................................... 21 3.3. Mul i a ia e analysis ................................................................................................ 25 4 1.2. Po uguese coas cha ac e is ics Po ugal is loca ed in he sub opical Lusi anic zone (Fig.1), in sou h-wes Eu ope, occupying mos o he wes e n pa o he Ibe ian Peninsula. Con inen al Po ugal's coas line is pa icula ly cha ac e ized by in e idal and shallow sub idal, ocky and sandy beaches. The sho es a e comple ely wa e-exposed om he No h o he Cen e o he coun y, om whe e hey become mode a ely wa e-exposed un il he Sou h o Po ugal (Gaspa e al., 2019). The sea su ace empe a u e pa e n is di e en in he no h and sou h o Po ugal, in he win e i luc ua es be ween 12ºC in he no h, o 16.5ºC in he sou h. In he summe , he empe a u e a ies om 18°C in he no h, o 22°C in he sou h. F om June o Oc obe occu s a e y impo an phenomenon nea he no he n coas ha b ings cold, mine al- ich, deep wa e o he su ace, he eby dec easing coas al wa e empe a u e o 16°C. This phenomenon is called “Upwelling” esponsible o en iching his egion wi h nu ien s and he e o e inc easing p oduc i i y (CMIA, 2012; Gaspa e al., 2019). In he summe , he wo main cu en s a ec ing he Po uguese coas a e: he Cana y Cu en , o igina ing om he no h and wi h a s ong sou hwa d low (12 cm s−1), and he Azo es Cu en , ha en e s he egion in he sou h, es ablishing a wes o eas ci cula ion. In win e , he Azo es Cu en p esen s wice he eloci y and he e is li le ci cula ion o seawa e in he egion. The No h coas o Po ugal is a ec ed by a semi-diu nal idal egime, wi h he la ges sp ing ides eaching 4m. Wi h a dominan swell om he wes and no hwes , his s aigh coas is highly exposed o a pa icula ly in ense wa e ac ion. The mos common wa e heigh s a e 1.5 o 2m, wi h an in e al pe iod o 11–13s, and du ing win e wa e ex eme e en s, wa e heigh alues can each abou 7– 11 m. In e ms o he salini y o seawa e , i can a y om 35% o 26% along he Po uguese mainland, depending on he p oximi y o esh wa e sou ces (Gaspa e al., 2019). In e ms o li hology, he no h Po uguese coas is a e y agmen ed habi a . This a ea is domina ed by ocky ee s, pebbled bo oms, and so -bo oms esul ing om ma ine e osion (Ca ei a-Flo es e al., 2023). So -bo oms a shallow subli o al a e es ic ed o pa ches su ounded by la ge ex ensions o boulde s and ocky subs a es, he la e being he p edominan habi a (Veiga e al., 2017). These a e some o he unique cha ac e is ics o he Po uguese coas , which is s ongly in luenced by a g ea clima ic di e si y, allowing o g ea biological ichness (bo h lo a and auna) along i s app oxima ely 830 km s ip (B aun-Blanque e al., 1973). 5 1.3. So -bo oms So -bo om subs a es co e mos o he wo ld’s ocean bo om, and only a ela i ely small p opo ion is o med o p ima y o seconda y ha d bo oms (Cas elli, A. La dicci e al., 2004). Co e ing abou 70% o he Ea h’s su ace, his is he la ges ecosys em on ou plane in a eal co e age (Snelg o e, 1997). So -bo om sub idal habi a s include all o he unconsolida ed subs a e a eas on he ocean bo om (clay, sand, g anule pebbles), anging om g a el o ine muds (Fig.2). Some sedimen s a e uni o m in g ain size, some a e mixed, some a e biological in o igin and o he s a e geological (Snelg o e, 1997) These habi a s p o ide an essen ial subs a e o he dominan biomass o o ganisms p esen o li e, h i e and main ain a subs an ial pa o he wo ld’s biodi e si y (Snelg o e, 1998). This way, in iew o hei widesp ead dis ibu ion and he impo ance and di e si y o ben hic in aunal assemblages, he so -bo oms con ain se e al sys ems ha a e o ecological in e es (Cas elli, A. La dicci e al., 2004). Al hough so -bo oms a e a la ge ecosys em, only a small pe cen age o hei mac oben hic auna has been s udied and mos o i s species a e s ill undesc ibed (Snelg o e, 1998). As such, i is impo an o imp o e ou knowledge o i s biodi e si y (Bou oumi e al., 2021). In he No h o Po ugal, he e a e ew s udies ega ding so -bo oms and hei mac oben hic assemblages, like, o example, Veiga e al. (2017). The e a e s udies ca ied ou in Viana do Cas elo conce ning so -bo oms, Sousa e al. (2006,2007), bu hese we e ca ied ou in he Lima es ua y and no exac ly in he coas al a ea. The e o e, his is a poo ly s udied habi a and he e is an inc ease in he need o hese ypes o s udies, pa icula ly in he ace o inc easing an h opogenic p essu es and en i onmen al changes. 6 1.4. Mac oben hic auna Mac o auna cons i u es a g oup o animals cha ac e ized by hei size, ha may be abundan in so -bo oms. This habi a is de ined by a combina ion o sedimen s ypes, including sand, mud, and g a el, which se es as an essen ial subs a e o he de elopmen and exis ence o his dominan biomass o o ganisms (Snelg o e, 1998). The size o hese o ganisms is de e mined by he mesh o a sie e on which hey can be ound a e he emo al o some o all o he sedimen pa icles. Fo mac o auna, ha means sie es wi h mesh sizes be ween 500 mm (0.5 mm) and 5 cm (Wa ling, 2019). The mac oben hic communi y is complex and encompasses a huge a ay o li e wi h many phyla in ol ed (Sau abh, 2014) such as: annelids, molluscs (e.g. bi al es and gas opods), and c us aceans (e.g. amphipods and decapods). Ben hic in e eb a es can be di e en ia ed by he posi ion hey occupy on o in bo om sedimen s. The e a e wo g oups: in auna, cha ac e ized by animals ha li e in sedimen s, almos all annelids and bi al es belong o his Figu e 2- Sea loo li hology, a ailable in: h p://po al.gpla es.o g/cesium/? iew=seabed; 7 ca ego y; and epi auna, which a e he o ganisms ha li e on he su ace o bo om sedimen s, many c us aceans and gas opods (Tagliapie a & Sigo ini, 2010). Mac oben hic in e eb a es in so -bo oms a e highly di e se in axonomy, mo phology, unc ionali y, mobili y and li e his o y cha ac e is ics (Óla sson, 2021). Mos mac o aunal species dis ibu ions appea o be ela ed o di e ences in sedimen ype, empe a u e, salini y and physical dis u bance. All o hese a iables ac oge he o c ea e physical and ecological cons ain s on species' dis ibu ions (Snelg o e, 1998). Mac oben hic assemblages play e y impo an oles in he ecology and unc ioning o so -bo oms. They s uc u e and oxygena e he bo om by ewo king sedimen s, h ough bu owing and unneling ac i i ies, hey “s i ” he sedimen and he po ewa e , mo ing pa icles a ound ha migh come in o con ac wi h o he animals who can use hem o ood. A ela ed ac i i y is he c ea ion o new habi a s o smalle meio aunal species, by he cons uc ion o la ge bu ows h ough which oxygena ed wa e is pumped (Wa ling, 2019). Since mac o auna is so abundan and capable o p oducing la ge numbe s o o sp ing, and in some cases o apid ep oduc ion, such o ganisms a e equen ood i ems o a a ie y o la ge animals, including c abs, ish, bi ds, and whales (Wa ling, 2019). The e o e, ben hic in e eb a es play his impo an link be ween p ima y p oduc ion wi h highe ophic le els, by il e ing phy oplank on and hen ac ing as a ood sou ce o la ge o ganisms (Tagliapie a & Sigo ini, 2010). Due o hei abundance and “in e media e” posi ion in he aqua ic ood chain, ben hic o ganisms play an essen ial ole in he na u al low o ene gy and nu ien s. (Sau abh, 2014). Ben hic in e eb a es also o m a majo componen o he o e all animal biodi e si y o aqua ic ecosys ems. The o al axonomic ichness o in e eb a es may exceed he ichness o all e eb a e g oups combined by wo o h ee imes (Sau abh, 2014). In addi ion, se e al ben hic in e eb a es, pa icula ly bi al es and decapods, a e consumed by humans, and o he s, such as annelids, a e used o ec ea ional pu poses as ishing bai (Tagliapie a & Sigo ini, 2010). Ben hic assemblages a e o en used as biological indica o s and a e e ec i e and use ul o he assessmen o coas al sys em quali y because hey can p o ide in o ma ion on en i onmen al condi ions, ei he due o he sensi i i y o single species o because o some gene al ea u e ha makes hem in eg a e en i onmen al signals o e a long pe iod (Tagliapie a & Sigo ini, 2010). A ew o hese ea u es a e, o ins ance: a display o a seden a y li es yle o limi ed mobili y, es ic ing hei abili y o a oid ad e se condi ions, in e media e ophic le el posi ions, ela i ely 8 long li e-span, axonomic and unc ional di e si y, a ying esponses o changes in en i onmen al s ess and hei easily quan i a i e sampling (Ma in e al., 2005). Wi hin so -bo om ecosys ems, subli o al mac oben hic assemblages ha e been less s udied han hose om he in e idal and emain la gely unknown (Veiga e al., 2017). Since shallow ma ine a eas a e among he mos endange ed ecosys ems wo ldwide, and he impac o use and abuse will no doub inc ease, e alua ing and unde s anding mac oben hic biodi e si y in hese habi a s is e y impo an (G ay & Ellio , 2009). 1.5. An h opogenic p essu es The wo ld’s popula ion is unde going a apid u baniza ion, ma ked by a signi ican mig a ion end owa ds coas al egions. Popula ion densi y a he coas is con inuously inc easing, leading o a g ea e concen a ion in coas al ci ies. These ci ies a e hubs o anspo and ade, gi en ha human densi y is s ongly ela ed o esou ce exploi a ion, and ine i ably leads owa ds nea sho e de elopmen (Todd e al., 2019). This de elopmen usually s a s wi h a ha bo , o acili a e na iga ion and ishing ac i i ies, bu e en ually leads o he cons uc ion o o he s uc u es. “Ocean sp awl” is a e m used o desc ibe he p oli e a ion o human-made ha d s uc u es in he ma ine en i onmen . This comp ises coas al in as uc u es, such as a i icial sho e de enses (e.g., b eakwa e s, g oins), as well as acili ies associa ed wi h ha bo s and docks (Todd e al., 2019). Such enginee ing s uc u es, like a i icial coas al p o ec ion s uc u es, a e e y common along Eu opean coas s. They can shel e o expose a sho eline o wa es om speci ic di ec ions, al e ing p ocesses and sedimen in e ac ion, and p oducing land o ms ha would no e ol e in he absence o he s uc u e (Jackson e al., 2015). B eakwa e s a e buil o mi iga e coas al e osion by educing wa e ac ion, and his happens h ough a combina ion o e lec ion and dissipa ion o incoming wa e ene gy. When used o ha bo s, b eakwa e s a e cons uc ed o c ea e su icien ly calm wa e s o na iga ion, p o ec ion o ha bo acili ies, and o he human ac i i ies (Lemos e al., 2017). The e o e, hese s uc u es al e hyd odynamics, by in e up ing wa e ac ion and modi ying he wa e ci cula ion, and hus sedimen a y cha ac e is ics, by a ec ing i s anspo and leading o changes in bo om opog aphy, sedimen g ain size, and o ganic con en o he su ounding habi a s (Be asi e al., 2007; Ma in e al., 2005). Fu he mo e, hey c ea e a ba ie o mo emen along he sho e, leading o al e ed pa e ns o la al supply and ood a ailabili y o he p esen mac o auna (Walke e al., 2008). 9 In some hea ily u banized egions, en i e habi a s ha e been los as a i icial s uc u es p oli e a e o e as dis ances, since hese a e eplaced by conc e e and g ani e. All hese changes al e ecological connec i i y, and ha e signi ican e ec s on ma ine assemblages (Bishop e al. 2017). Mac oben hic communi y s uc u e s ongly depends on a ange o bio ic and abio ic ac o s, ha seem o con ol di ec ly o indi ec ly i s abundance and dis ibu ion (Cas elli e al., 2004) by in luencing ood a ailabili y, bo om-wa e oxygena ion, and la al dispe sion (Veiga e al., 2017). Wa e ac ion, which con ols he physical en i onmen , and sedimen cha ac e is ics a e conside ed one o he main physical ac o s a ec ing he dis ibu ion o shallow so -bo oms ben hic auna (Be asi e al., 2007), wo ac o s widely al e ed due o he p esence o a i icial s uc u es, as e e ed o abo e. Thus, all hese changes and dis u bances a ec he composi ion and s uc u e o mac oben hic assemblages and could esul in di e en colonizing assemblages (Todd e al., 2019). Ocean sp awl is a undamen al and p ominen aspec o u banized ma ine en i onmen s, wi h man-made s uc u es o ming he majo i y o sho elines in many coas al ci ies and al e ing habi a s deep in o he sub idal zone (Todd e al., 2019). Hence, while hese s uc u es p o ide aluable p o ec ion o human in as uc u e, hey also ha e signi ican impac s on so -bo oms ben hic assemblages, as hey in luence species abundances, dis ibu ion pa e ns, and communi y s uc u e (Be asi e al., 2007). 1.6. Goals In Eu ope, he e a e nume ous s udies ega ding he e ec s o a i icial s uc u es on mac oben hic auna. Ma in e al. (2005) is one o many esea ch s udies in eg a ed in an Eu opean-wide s udy o iden i y, desc ibe and quan i y he impac s o a i icial s uc u es on he biodi e si y and unc ioning o so -bo oms mac oben hic assemblages. This s udy included di e en kinds o a i icial s uc u es in di e en coun ies, such as Spain, I aly and he Uni ed Kingdom. Un o una ely, in he No h o Po ugal, he e a e no s udies ega ding he e ec s o a i icial p o ec ion s uc u e on so -bo oms mac oben hic auna. Al hough he e a e s udies ca ied ou in Viana do Cas elo ega ding so -bo oms, Sousa e al. (2006,2007), hese we e ca ied ou in he Lima es ua y, assessing he i e g adien , and hus being a s udy unde di e en hyd odynamic condi ions and di e en en i onmen al pa ame e s om he ones in his s udy. 10 Thus, since he mac oben hic assemblages a e widely undesc ibed in so -bo oms, and he e ec s o a i icial p o ec ion s uc u es on such assemblages is ye highly unknown, and conside ing he high p esence o a i icial s uc u es along he Po uguese coas , he e is a need o hese ypes o s udies o inc ease o a be e unde s anding o ou auna and o help imp o e managemen decisions. This s udy aims o compa e and explo e he di e ences be ween mac oben hic assemblages inhabi ing he shallow so -bo oms in a na u al wa e exposed a ea and an a ea p o ec ed by an a i icial s uc u e. Unde s anding how he p esence o absence o his a i icial p o ec ion in luences he species di e si y and assemblage s uc u e in so -bo oms is a e y impo an goal in managing he impac o hese ha d s uc u es. Fo ha , his s udy was conduc ed on he no he n coas o Po ugal, in Viana do Cas elo, in wo a eas: Co al Bay (41.6836° N, 8.8457° W) and Cabedelo (41.6791° N, 8.8326° W). Co al is a shallow bay p o ec ed by one b eakwa e and Cabedelo is exposed o wa e ac ion, and i is expec ed o obse e di e ences in he mac oben hic assemblages be ween hese wo a eas. The p oposed hypo hesis is “ ha he b eakwa e will modi y wa e and sedimen cha ac e is ics and hus a ec he s uc u e o mac oben hic assemblages”. 11 2. Ma e ial and Me hods 12 2. Ma e ial and Me hods 2.1. S udy a ea This s udy was ca ied ou in he No h o Po ugal in Viana do Cas elo. This ci y has de eloped and occupied he igh ma gin o he Lima Ri e es ua y and he adjacen coas al a ea, he la e being occupied by comme cial ha bo acili ies. In he las 400 yea , Viana do Cas elo ha bo has su e ed coun less ans o ma ions wi h he cons uc ion o di e en s uc u es o imp o e i s p o ec ion and i s na iga ion (Fig.3) (Geopa que Li o al Viana do Cas elo, 2020). Viana’s ha bo wa e s a e p o ec ed by wo b eakwa e s: he ou e and main one, de eloping on a 170º bea ing and wi h 2170 me e s (“Molhe Ex e io ”), and he inne one, wi h abou 700 me e s on a Sou h/sou hwes e ly o ien a ion (“Molhe do Cabedelo”) (Fig.4). These wo hea y cons uc ions we e buil be ween 1977 and 1981 and induced p o ound changes in allu ial anspo , essen ial o he exis ence o he ha bo a ea, namely he ishing and comme cial ha bo s (Vale, 2008). The dis u bance o he p edominan swell di ec ion, om he no hwes , a he head o he main b eakwa e , gene a es a wa e pa e n om sou hwes o he in e io o he mou h o he Lima Ri e , esponsible o he c ea ion o P aia do Co al (Geopa que Li o al Viana do Cas elo, 2020). These wo a eas a e he ones chosen o he sampling, Cabedelo (41.6791° N, 8.8326° W) which is exposed o wa e ac ion and Co al (41.6836° N, 8.8457° W), which is p o ec ed by he main b eakwa e , he a i icial p o ec ion s uc u e we ocused on o his s udy (Fig.4). 13 2.2. Sampling design Sampling was conduc ed on h ee da es: July 2021, Decembe 2021, and May 2022. A h ee- ac o sampling design was used o explo e he mac oben hic assemblages p esen in p o ec ed and exposed shallow sub idal so -bo oms. A each locali y, h ee si es we e andomly chosen (Fig.4). Sedimen samples wi hin each si e we e andomly collec ed, using a Van Veen g ab (sampling su ace o 0.12 m2) o a maximum dep h o 10m. A each si e, a o al o h ee g abs we e collec ed o mac o aunal iden i ica ion. Once on boa d he boa , he g ab was opened abo e a plas ic bucke and he sample was gen ly emo ed and hen labeled (Fig.5). A sample o 100ml o sedimen o each habi a was e ie ed o pos e io g anulome ic composi ion. The salini y o he wa e was measu ed a jus one si e in each habi a , on each da e, making a o al o 6 measu emen s. Figu e 3- Map om 1913 ep esen ing Viana do Cas elo coas al a ea, o e layed wi h a sa elli e image o Viana in 2022; 20 3. Resul s 3.1. En i onmen al pa ame e s 3.1.1. Salini y The ANOVA analysis showed ha he e we e signi ican di e ences in he Da e and Da e x Habi a ac o s (Table 1). The pos hoc analysis showed he e a e signi ican di e ences in he July 2021 and Decembe 2021. The mean alue o salini y in July was ≈32 and ≈35 o Co al and Cabedelo, espec i ely, and in Decembe his alue was ≈25 and ≈33 o Co al and Cabedelo, espec i ely (Fig.8). Table 1- Resul s o ANOVA salini y. *p<0.05, signi ican di e ences indica ed in bold; Sou ce DF MS F P F e sus Da 2 40.6739 130.74 0* RES Ha 1 67.2800 3.21 0.2152 DaxHa DaxHa 2 20.9817 67.44 0* RES RES 12 0.3111 To al 17 Figu e 8- Salini y o he wo habi a s on he h ee di e en da es. *indica es he signi ican di e ences; * * 21 3.1.2. G anulome y This analysis showed ha Co al sedimen s had a highe con en o o ganic ma e , wi h a alue o 3.1%, whe eas Cabedelo sedimen s had a alue o 0.9%. In e ms o g anulome y, Co al had highe pe cen ages o ine sedimen s: e y ine sand (20.4%) and ine sand (58.5%); and Cabedelo had highe pe cen ages o medium sand (34.2%), coa se sand (42.8%), e y coa se sand (3.9%) and ine g a el (3.2%) (Table 2). Table 2- G anulome y o he collec ed sedimen samples. Fine g a el (2-4 mm), e y coa se sand (1-2 mm), coa se sand (0.5-1 mm), medium sand (0.25-0.5 mm), ine sand (0.125-0.25 mm), e y ine sand (0.063-0.125 mm) and sil /clay (<0.063 mm). Habi a MO (%) %(<63um) %63um %125um %250um %500um %1mm %(>2mm) Co al 3.1 3.5 20.4 58.5 15.3 1.82 0.32 0.08 Cabedelo 0.9 3.8 4.8 7.3 34.2 42.8 3.9 3.2 3.2. Richness, di e si y and abundance In his s udy, a o al o 18 samples we e collec ed in wo di e en habi a s, in which 6537 indi iduals we e iden i ied belonging o 97 species (Appendix 1). Co al July 2021 p esen ed he highes abundance o indi iduals and Cabedelo Decembe 2021 he lowes , wi h 2488 and 244 indi iduals espec i ely. In e ms o species ichness, Co al July 2021 p esen ed he highes numbe o species, and he lowes numbe o species eco ded was 33, in Co al in Decembe 2021 as well as Cabedelo in May 2022 (Table 3). Table 3- Numbe o indi iduals and species ichness in each habi a on he h ee di e en da es; July 2021 Decembe 2021 May 2022 Numbe o indi iduals Co al 2488 783 2010 Numbe o species Co al 70 33 44 Numbe o indi iduals Cabedelo 481 244 531 Numbe o species Cabedelo 34 36 33 22 The iden i ied mac o auna we e dis ibu ed by 5 Phylum: Mollusca, Annelida, Nema oda, Echinode ma a and A h opoda. The phylum wi h he highes numbe o indi iduals was Annelida (3929 in a o al o 6536), as well as species (44 in a o al o 98) in all da es and habi a s. The phylum wi h highes abundance ollowing Annelida, was Mollusca (1256 indi iduals) and A h opoda (971 indi iduals) (Fig.9). The mos abundan axa in Co al July 2021 was Capi ella capi a a (Fab icius, 1780), in Cabedelo July 2021 was Nep hys longose osa (Ö s ed, 1842), in Co al Decembe 2021 was Chae ozone sp. (Malmg en, 1867), and in Cabedelo Decembe 2021 was Donax unculus (Linnaeus, 1758). Finally, in Co al May 2022 he mos abundan axa was Oligochae a, and in Cabedelo May 2022 was Spio sp. (Fab icius, 1785) (Appendix 1). Figu e 9- To al numbe o indi iduals (A) and pe cen age (B) o each Phylum in he wo habi a s h oughou he di e en da es; A B 23 The Shannon di e si y index ANOVA displayed signi ican di e ences in he ac o Da e (Da) (p<0.05) (Table 4). The pos hoc analysis didn’ show any signi ican di e ences and he g aph (Fig.10) shows ha his index is e y simila in he wo habi a s in he h ee di e en da es, being July 2021 he one wi h highe alues and a sligh ly bigge di e ence, wi h Co al p esen ing a mean alue o 2.41 and Cabedelo a mean alue o 2.11. Table 4- Resul s o ANOVAs o Shannon di e si y index (H), Numbe o indi iduals (N) and Species ichness (S). * p<0.05, signi ican di e ences indica ed in bold; SOURCE d H N S MS F MS F MS F Da 2 1.1175 9.64* 114.3389 3.10* 466.7963 6.94* Ha 1 0.2186 2.23 539.2886 21.07* 755.6296 2.68 Si (DaxHa) 12 0.1159 0.92 36.9032 10.06* 67.2222 13.7* DaxHa 2 0.0978 0.84 25.5975 0.69 282.0185 4.2* Residual 36 0.1257 3.6682 4.9074 To al 53 T ans . None Sq (X+1) None Coch an’s es 0.3167 ns 0.3016 ns 0.2415 ns Figu e 10- Shannon di e si y index o he wo habi a s on he h ee di e en da es; 24 The numbe o indi iduals ANOVA displayed signi ican di e ences (p<0.05) (Table 4). The pos hoc analysis showed signi ican di e ences in he ac o Da e, Habi a , and Si (DaxHa), and he e we e signi ican di e ences in he numbe o indi iduals in he wo habi a s (Fig.11). The mean o indi iduals in Co al was ≈13 and he mean in Cabedelo was ≈7. The species ichness ANOVA displayed signi ican di e ences (p<0.05) (Table 4). The pos hoc analysis showed signi ican di e ences be ween he ac o Habi a and Da e, and he e we e signi ican di e ences in he i s da e, July 2021, be ween he wo habi a s (Fig.12). In Co al he mean numbe o species was close o 30 and in Cabedelo was almos 13. Figu e 11-Numbe o indi iduals o he wo habi a s on he h ee di e en da es. * indica es he signi ican di e ences; 25 3.3. Mul i a ia e analysis 3.3.1. Pe mano a, PERMDISP and nMDS Resul s o PERMANOVA analysis o he composi ion o assemblages showed a signi ican in e ac ion be ween Habi a and Da e (Table 5). Pos hoc analysis e ealed signi ican di e ences in mac o aunal assemblages be ween habi a s a each da e (Table 6), showing ha he assemblages in he wo habi a s we e di e en . Figu e 12- Species ichness in he wo habi a s on he h ee di e en da es. * indica es he signi ican di e ences; 26 Table 5- Resul s o PERMANOVA es ing di e ences in mac oben hic assemblage s uc u e ac oss he s udied habi a s. Analyses based on B ay-Cu is dissimila i y ma ix om squa e- oo ans o med da a. All es s used 999 andom pe mu a ions. Resul s o PERMDISP analysis. * p<0.05, signi ican di e ences indica ed in bold; Table 6- Pos hoc analyses o PERMANOVA. * p<0.05, signi ican di e ences indica ed in bold; Despi e he PERMDISP analysis indica ing ha he dispe sion o eplica es was signi ican among habi a s (Table 5), he PERMDISP pai wise compa isons showed ha he dispe sion o eplica es did no p o ide a signi ican con ibu ion o he obse ed di e ences be ween Co al and Cabedelo in e e y da a (Table 7), which we e clea ly sepa a ed in he nMDS plo (Figu e 13). Table 7 - PERMDISP pai wise compa ison esul s; Sou ce d MS Pseudo-F p Unique pe ms Ha 1 36086 5.6851 0.09 38 Da 2 14544 5.045 0.001* 999 HaxDa 2 6347.5 2.2019 0.002* 998 Si (HaxDa) 12 2882.8 2.569 0.001* 998 Residual 36 1122.1 To al 53 PERMDISP F: 4.793 P(pe m): 0.006 G oups Co alxCabedelo p (pe m) Unique pe ms p (MC) July 2.279 0.1018 10 0.0093* Decembe 1.69 0.0983 10 0.0333* May 4.0295 0.1009 10 0.0002* G oups p(pe m) Co al July, Cabedelo July 1.4982 0.241 Co al Dec., Cabedelo Dec. 1.7506 0.113 Co al May; Cabedelo May 1.5273 0.193 27 3.3.2. Simpe analysis The dissimila i y be ween Co al July 2021 and Cabedelo July 2021 was 79.41%, wi h 44 axa being esponsible o 90.37% o his dissimila i y. I is possible o e i y ha he species wi h he highes con ibu ion belonged o Bi al ia and Polychae a. The highes con ibu ion belonged o Ab a alba (W. Wood, 1802), wi h a pe cen age o 7.82, ollowed by Capi ella capi a a wi h a pe cen age o 6.83. The species wi h he leas con ibu ion in his da e was Glyce a idac yla (Schma da, 1861), wi h a pe cen age o 0.76%. The mos abundan species in Co al is Ab a alba and in Cabedelo was Neph ys longose osa (Table 8). In July 2021, 18 axa we e exclusi e o Co al and only one axa was exclusi e o Cabedelo. The e we e 25 species associa ed wi h bo h habi a s (Fig.14). O all he axa p esen in his analysis, 12 belonged o Polychae a , mos ly belonging o he ollowing O de s: Phyllodocida, Spionida and Te ebellida. The es o he axa was dis ibu ed ac oss Bi al ia, Amphipoda, Cumacea, Gas opoda, Oligochae a, Nema oda, Decapoda, Copepoda, Echinode ma a, Isopoda and Malacos aca. -Co al July 2021 -Cabedelo July 2021 -Co al Decembe 2021 -Cabedelo Decembe 2021 -Co al May 2022 -Cabedelo May 2022 Figu e 13- nMDS plo o cen oids Co al (black) and Cabedelo (whi e) a h ee da es o sampling; 28 Table 8- A e age abundance, con ibu ion o indi idual axa and cumula e pe cen age (Cum %) om Co al and Cabedelo in July 2021; Co al Cabedelo Taxa A . Abund A . Abund Con ib.% Cum.% Ab a alba 5.97 0.19 7.82 7.82 Capi ella capi a a 5.5 0.3 6.83 14.65 Mediomas us agilis 4 0.36 4.7 19.35 Ensis siliqua 2.21 0 3.2 22.56 Ampelisca b e ico nis 2.23 0 3.19 25.74 Th acia phaseolina 1.83 0 3.17 28.92 Oligochae a 2.77 0 3.12 32.04 Ba hypo eia sp. 0.16 1.92 2.86 34.9 Spisula sub unca a 2.12 0.3 2.74 37.64 Owenia usi o mis 2.1 0.3 2.58 40.22 Donax unculus 0.11 1.7 2.56 42.78 T i ia e icula a 1.8 0 2.54 45.32 Diogenes pugila o 0.41 1.76 2.48 47.8 Cumopsis longipes 0.54 1.94 2.46 50.26 Chae ozone sp. 1.98 0 2.4 52.66 Scolelepis can ab a 0.16 1.37 2.25 54.91 Spio sp. 3.37 2.62 2.21 57.12 Neph ys longose osa 1.59 2.85 1.93 59.05 Co ophium sp. 1.43 0.22 1.81 60.86 Eu ydice 0.3 1.02 1.72 62.58 Pa ica dium minimum 1.07 0 1.64 64.22 P ionospio sp. 1.41 0 1.62 65.84 No o opis alca us 1.74 1.07 1.55 67.38 Cylichna cylind acea 1.29 0 1.54 68.92 Calanoida 0.74 0.75 1.45 70.37 Cap ella sp. 1.11 0.11 1.43 71.8 Echinode ma a la a 2 1.05 0 1.41 73.21 Ophiu a sp. (ju enile) 0.79 0.11 1.29 74.5 S henelais boa 1.07 0 1.28 75.78 E eone pic a 0.83 0.22 1.22 77.01 Echinoca dium co da um 0.52 0 1.15 78.16 Lagis ko eni 0.94 0 1.11 79.27 Nema oda 0.92 0.11 1.11 80.39 Echinode ma a la a 1 0.57 0.51 1.1 81.49 Tanaissus bambe i 0.46 0 1.05 82.54 Pon oc a es a ena ius 0.22 0.66 1.04 83.58 T i ia sp. (ju enile) 0.33 0.19 0.96 84.53 Mac oclymene san ande ensis 0.84 0 0.95 85.48 Eocuma doll usi 0 0.57 0.92 86.4 Lanice conchilega 0.71 0 0.85 87.25 29 The dissimila i y be ween Co al Decembe 2021 and Cabedelo Decembe 2021 was 78.79%, wi h 30 axa being esponsible o 90.77% o his dissimila i y. The axa wi h he highes con ibu ion o he dissimila i y belonged o Spionida and Nema oda. The highes con ibu ion belonged o P ionospio sp. (Malmg en, 1867), wi h a pe cen age o 7.86, ollowed by Nema oda wi h a con ibu ion o 7.69%. The species wi h he lowes con ibu ion in his da e was Rissoa pa a (da Cos a, 1778), wi h a con ibu ion o 0.99%. In bo h habi a s he mos abundan species was Donax unculus (Table 9). In Decembe 2021, he e we e 6 axa exclusi e o Co al and 9 we e exclusi e o Cabedelo. In o al, he e we e 15 axa associa ed o bo h si es (Fig.15). Among all he species, 12 belonged o Polychae a, wi h he majo i y belonging o he ollowing O de s: Phyllodocida, Spionida and Te ebellida. The es o he axa was dis ibu ed h ough Bi al ia, Amphipoda, Gas opoda, Nema oda, Decapoda, Copepoda and Malacos aca. Tapes homboides 0.64 0 0.8 88.05 Eumida so. 0.65 0 0.78 88.83 Magelona ili o mis 0.11 0.5 0.77 89.6 Glyce a idac yla 0.49 0.22 0.76 90.37 Figu e 14- Exclusi e and common species in he habi a s in July 2021; 36 4. Discussion Hyd odynamic and sedimen cha ac e is ics a e key d i e s in shaping mac oben hic assemblages on nea -sho e ecosys ems, he e o e any modi ica ion ha may al e hese p ocesses may ha e an una oidable impac on he ecology o mac oben hic assemblages. Any s uc u e placed wi hin a coas al en i onmen changes he wa e egime and sedimen a y p ocesses, a ec ing he species composi ion, abundance and ophic s uc u e o in e eb a e assemblages ha inhabi so - bo oms en i onmen s (Ma in e al., 2005). Co al bay is si ua ed igh nex o he mou h o he Lima Ri e and is p o ec ed by he 2170-me e b eakwa e . When he i e lows in o he coas al a ea and he wo di e en habi a s come in con ac , o ganisms, o ganic ma e and nu ien s can be ans e ed om one habi a o ano he (Ba os e al., 2001). When he eshwa e lows in o he coas al a ea, he e is an immedia e inpu o pollu an s, nu ien s, and o ganic ma e in o he ocean basin (Snelg o e, 1998). A i icial s uc u es, such as he Viana’s main b eakwa e , modi y local cu en s, en apping he o ganic ma e and he exis ing o ganic ma e ial, such as algae and deb is, which c ea es an o ganic build- up in he adjacen sedimen s (Be asi e al., 2007). Since his a ea is iche in o ganic ma e han Cabedelo a ea (Table 2), he e is a g ea quan i y o po en ial ood esou ces, and hus deposi eede s domina e he communi y, as p e iously epo ed by o he au ho s (Ma in e al., 2005; Sousa e al., 2006). The mos abundan axa in he p o ec ed a ea, Co al, in all da es a e mos ly Annelida (Fig.9): C. capi a a, Mediomas us agilis (Rasmussen, 1973), Chae ozone sp. and Oligochae a; bu he e is also a high p esence o he bi al e A. alba (Appendix 1). Ou esul s ag ee wi h Ga y and Ellio (2009) and Sousa e al. (2007), ha obse ed high abundance o C. capi a a and Chae ozone sp . in a eas wi h: ine sedimen s ich in o ganic ma e and inc eased o ganic ma e loading a eas. Ou esul s also ag ee wi h Be asi e al. (2007) ha epo ed ha he a ea p o ec ed by an a i icial p o ec ion s uc u e hos ed an in aunal communi y cha ac e ized by deposi eede s and sub-su ace deposi eede s, such as C. capi a a . The p esence o C. capi a a popula ions, in a eas whe e a i icial p o ec ion s uc u es a e p esen , is an index o assessing he dis u bance e ec s on assemblages, pa icula ly as ega ds o ganic en ichmen (Ma in e al., 2005). In ac , Ma in e al. (2005) concluded ha his species was mo e abundan in a eas p o ec ed om wa e mo emen by an a i icial p o ec ion s uc u e. 37 Oligochae a, Chae ozone sp. , M. agilis and C.capi a a a e conside ed oppo unis ic, which is de ined as a species who adap s o li e in a lee ing and unp edic able habi a by elying on a high g ow h a e o make use o momen a y esou ces (G assle & G assle, 1974). These ypes o species ha e he capabili y o espond apidly o he sudden appea ance o inc eased o ganic ma e ha can be used as ood (Wa ling, 2019), ep oduce apidly o use up he esou ces be o e o he compe ing species can exploi he habi a , and hen dispe se in sea ch o o he new habi a s as he exis ing becomes unsui able (G assle & G assle, 1974). Oligochae a and Chae ozone sp. a e exclusi e o Co al, no being ound in Cabedelo, and C. capi a a and M. agilis a e disp opo ionally mo e abundan in Co al when compa ed o he numbe s ound in Cabedelo (Appendix 1). This ein o ces once mo e ha he p esence o he b eakwa e leads o a buildup o o ganic ma e and he appea ance o oppo unis ic species, such as hese ones. Acco ding o Sousa e al. (2006, 2007), he bi al e A. alba is e y abundan in a eas wi h high o ganic loads, and Be asi e al. (2007) concluded ha A. alba p e e s hyd odynamically less s essed a eas and o ganically en iched bo oms, and ha his bi al e g ows quickly when ood is a ailable. Ou esul s showed ha he numbe o indi iduals o A. alba ound in Co al we e much highe han hose ound in Cabedelo (Appendix 1) con i ming he p e e ences o his bi al e o o ganic ich habi a s. Cabedelo is exposed o wa e ac ion and is unde e y di e en condi ions om hose o Co al. In Cabedelo, he mos abundan axa a e: Neph ys longose osa and Cumopsis longipes (Doh n, 1869) in July 2021, D. unculus in Decembe 2021 and Spio sp. in May 2022 (Appendix 1). The communi y in his habi a is di e en om Co al, being composed by suspension eede s and p eda o s. Species om he genus Donax ypically occupy he shallow subli o al o exposed beaches, high ene gy en i onmen s wi h s ong wa e ac ion o high cu en speed. Despi e he equen dis u bances on he sedimen , caused by hyd odynamic condi ions, hese o ganisms a e well adap ed o main ain hei posi ions in such condi ions Donax species a e pa icula ly cha ac e is ic o highly p oduc i e a eas and ely on he collec ion o suspended pa icles om he wa e (Ansell, 1983). The polychae e N. longose osa is a ca ni o ous p eda o ha can be ound in he lowe in e idal zone, and mos commonly in well-so ed ine o medium sands (Ra a a e al., 2010). C. longipes is a species adap ed o li e in dynamic ecosys ems, being bo h apid and s ong enough in o de o cope wi h wa e condi ions, and eeds by il a ing he pa icles in he wa e column (Quillien e 38 al., 2018). Species o he genus Spio ha e di e en eeding habi s. Al hough hey can be deposi eede s and eed on o ganic ma e p esen , hey a e no necessa ily an indica o o o ganic ma e en ichmen . These species can also eed by il e ing he wa e column, such as D. unculus and C. longipes . Fu he mo e, in he AMBI analysis his species is anked in he III ecological g oup, whe eas Oligochae a, C. capi a a and Chae ozone sp. a e anked as IV and IV ecological g oups. The p esence o hese species indica es ha he condi ions and ood esou ces in Cabedelo a e e y di e en han he ones in he b eakwa e p o ec ed habi a . Since he e is no accumula ion o o ganic ma e in his habi a , he species he e p esen mus ind o he ways o subsis , o example p eda ion and il a ion. The eshwa e inpu om he Lima Ri e di ec ly a ec s he salini y in he p o ec ed a ea o Co al. Acco ding o Snelg o e (1998), his is an impo an a iable in coas al en i onmen s, due o i s ole in de ining he dis ibu ions o coas al species. This causes he wo ypes o wa e o mix, he eshwa e s ays a he su ace, and he sal wa e , which is dense , s ays close o he bo om, c ea ing a “ ood ap”, whe e he nu ien s ge apped in his mix u e o wa e ypes (Mendes, 2009). Addi ionally, his in lux causes he salini y le els o lowe in Co al. Whils in Cabedelo, a habi a a ec ed by high hyd odynamics, and a o ally ma ine habi a (appa en ly una ec ed by he i e ), hese salini y alues a e highe and s able h oughou he yea . This could explain he di e ence be ween he alues ob ained when compa ing he wo habi a s o his s udy (Fig.8). The communi y s uc u e in bo h habi a s had empo al oscilla ions in abundance and di e si y, p esen ing lowe alues in he win e , in Decembe 2021, and highe alues in May 2022, and in he summe ime, in July 2021 (Table 3). The assemblages main ained some s abili y h ough such empo al luc ua ions, wi h he dominan popula ions always p esen (Fig.9). The esul s o his s udy, abou he di e ences in he assemblages in he di e en habi a s, a e in line wi h o he s udies. Be asi e al. (2007) de ec ed signi ican di e ences in mac oben hic assemblages be ween loca ions p o ec ed by a i icial s uc u es and loca ions exposed o wa e ac ion. The loca ions shel e ed by a i icial s uc u es demons a ed an inc ease in mac oben hic species numbe and, in con as , he exposed zones p esen ed a poo le el o species and less di e si ica ion. They also concluded ha he ela i ely la ge mac oben hic auna occupied he mos exposed and shallowes loca ion, while he small ones se led in he mos shel e ed zones since he wa e agi a ion ends o inhibi hei deposi ion as well as he deposi ion o ine pa icles. Ou s udies also ag ee wi h Ma in e al. (2005), a s udy ha e alua ed a ious a i icial p o ec ion s uc u es all o e Eu ope, concluding ha “ he p esence o a i icial p o ec ion s uc u es induced 39 an o e all inc ease in di e si y a all he s udied a eas”. These esul s help suppo and explain he signi ican di e ences in he alues o numbe o indi iduals and species ichness (Table 3; Fig11,12). The sedimen cha ac e is ics is an impo an ac o in s uc u ing mac oben hic assemblages and also de e mining he ophic s a us o hese assemblages (Ma in e al., 2005). This a iable can be al e ed by he p esence o he b eakwa e , and he e o e, al e de communi y p esen in such habi a . Fo ins ance, ine o ganically ich muds end o con ain mo e bu owing deposi eede s, such as C. capi a a , whe eas coa se sedimen s usually ha bo mo e mobile animals and suspension eede s, o example D. unculus (Table 2) (Ma in e al., 2005). The e is an e iden di e ence be ween he assemblages in he wo habi a s. The wo habi a s a e unde di e en hyd odynamic condi ions due o he b eakwa e , which ul ima ely a ec s he ype o assemblages ha o m he e. Co al is p o ec ed om wa e ac ion by he b eakwa e , ha seems o ha e high in luence in sedimen cha ac e is ics and in he o ganic ma e buildup (Table 2). The ac ha Co al bay is loca ed igh nex o he i e mou h also inc eases he di e ences be ween he wo habi a s, since he i e can ha e a ma ked in luence on he sedimen dynamics and o ganic load and, hus, on he in aunal s uc u e and unc ioning (Ma in e al., 2005). In his habi a , whe e he e can be a ce ain le el o s ess and pollu ion, he mos sensi i e species become a e o pe ish and a e eplaced by oppo unis ic species (Sousa e al., 2007). This means ha , species p esen unde na u al condi ions migh disappea due o he p esen o he b eakwa e , bu a he same ime, di e en species a e able o colonize he new habi a as a esul o hese new condi ions (Ma in e al., 2005). In he o he hand, Cabedelo is subjec o in ense wa e ac ion, high cu en s, and sedimen dis u bance, meaning ha hese assemblages ha e di e en esou ces a ailable and di e en cha ac e is ics ha allow hem o inhabi such condi ions. Al hough he e is e idence in ano he s udy, (Veiga e al., 2014), wi h di e en en i onmen al pa ame e s measu ed, ha he i e s ills as e ec s in some coas al a eas a iables a ew kilome e s o he i e mou h, in his s udy ha does no happen. Cabedelo doesn’ seem o be a ec ed by he Lima Ri e , being only a ec ed by he condi ions o Viana sea. These di e ences a e also e iden in he AMBI analysis, ha shows he le els o dis u bance in each habi a . Co al is mo e dis u bed han Cabedelo, luc ua ing be ween “Sligh ly dis u bed” and “Mode a ely dis u bed” and ha ing species a ibu ed o ecological g oups wi h high ankings, meaning ha his could be a s essed and o ganic pollu ed habi a (Fig.17,18). 40 As expec ed, he mac oben hic assemblage a e di e en in esponse o he p esence o he b eakwa e . Th oughou his s udy is possible o see he clea e ec s o he b eakwa e on he sedimen and hyd odynamic cha ac e is ics and, consequen ly, on he s uc u e o mac oben hic assemblages o he so -bo oms o Viana do Cas elo. The e o e, he p oposed hypo hesis “ he b eakwa e will modi y wa e and sedimen cha ac e is ics and hus a ec he s uc u e o mac oben hic assemblages” is accep ed. The e is li le knowledge o he consequences o ocean sp awl on la ge spa ial a eas, bu gi en hei p ominence and scale hey a e likely o be signi ican (Todd e al., 2019). The spa ial scale o impac s om a i icial s uc u es depends on he ype o s uc u e, local hyd odynamic condi ions, and a a ie y o o he pa ame e s (Todd e al., 2019). As a i icial s uc u es sp ead ac oss long dis ances, in some o he mos densely u banized egions, en i e habi a s ha e been los . In o de o a oid hese la ge scale e ec s o habi a loss, agmen a ion and communi y change, he e ec s o a i icial s uc u es should always be minimized and he numbe o hese s uc u es should be educed o he minimum necessa y o p o ec he coas (Ma in e al., 2005). A i icial p o ec ion s uc u es ha ha e al eady been cons uc ed, canno ealis ically be emo ed. Finding ways o imp o e he ecological and social alue o hese coas al a eas, whils main aining hei enginee ing unc ions, is c ucial gi en ha he e a e likely o be mo e human sho elines buil in he o eseeable u u e (Todd e al., 2019). Fu he mo e, i is also e y impo an o y o ob ain u he e idence on he ecological impac s o such s uc u es, o help imp o e decision making p ocesses (Walke e al., 2008). Since he Po uguese coas is e y long, and he e a e many o he a i icial s uc u es dis ibu ed along he coas al a ea, mo e in es iga ions a e needed in his coun y so he e’s a be e unde s anding o he ull ex en o he changes caused by hese s uc u es and o see i he e is a pa e n along he coas . 41 5. Conclusion 42 5. Conclusion O e all, he main conclusions o his s udy a e: • The p esence o he b eakwa e a ec s and changes he so -bo om mac oben hic assemblages o he p o ec ed a ea, Co al, when compa ing hem o he assemblages o he exposed a ea, Cabedelo; • The mac oben hic assemblages o he p o ec ed a ea a e cha ac e ized by deposi - eede s, oppo unis ic species and, in gene al, by species wi h p e e ence o o ganically en iched bo oms; • The mac oben hic assemblages o he exposed a ea a e subjec o di e en condi ions and esou ces, so hey p esen di e en eeding habi s, such as il a ion and p eda ion; • The p o ec ed a ea is mo e di e se and has highe numbe o indi iduals han he exposed a ea; • The AMBI analysis shows ha he p o ec ed a ea is mo e dis u bed, and has mo e species a ibu ed o ecological g oups wi h high ankings han he exposed a ea; 43 6. Re e ences 44 6. Re e ences A onso, E., A nal, I., A on es, J., A zel, P., & Aug is, C. (2000). 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