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Hoeveel reuse-kelp is daar per vierkante meter?

Hoeveel reuse-kelp is daar per vierkante meter?


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In 'n hoë-digtheid reuse kelp (Macrocystis pyrifera) bedding, hoeveel "houvas" of wortels sal daar gemiddeld per vierkante meter seebodem wees?


Die digtheid van Macrocystis pyrifera is redelik veranderlik. Volgens Dayton et al. 1984 langs die kus van Suid-Kalifornië kan dit wissel van minder as 0,1 tot 1,0 $individue/m^2$. Die variasie hang af van die ligging, waar daar verskillende blootstellingsvlakke aan hoë-energiegolwe, opwellings wat voedingstowwe bevat, en predasie deur see-egels is.

Dayton, P. K., Currie, V., Gerrodette, T., Keller, B. D., Rosenthal, R., & Tresca, D. V. (1984). Pleisterdinamika en stabiliteit van sommige Kaliforniese kelp-gemeenskappe. Ekologiese monografieë, 54(3), 253-289. https://doi.org/10.2307/1942498


'n Uitslag om die kelp te red

Geskryf deur

Woord telling

Deel hierdie artikel

Artikel liggaam kopie

Terry Herzik duik al vir meer as 40 jaar vir rooi see-egels in Suid-Kalifornië. Hy ondersteun sy gesin deur die stekelrige ongewerwelde diere se gonades as die soesji-lekkerny te verkoop uni. Maar oor die afgelope eeu was Suid-Kalifornië se reuse-kelp-ekosisteme - die rooi egel se tuisveld - onder aanranding. Aangespoor deur mens-geïnduseerde omgewingsagteruitgang, het 'n bloeiende bevolking van vraatsugtige, kelp-krasende pers egels gehelp om hierdie eens welige woude in kaal woesteny te verander. In so 'n verminderde habitat het die rooi-egels se getalle (en hul gonades) gekrimp.

So, drie jaar gelede, het Herzik by 'n ambisieuse projek aangesluit wat deur die niewinsorganisasie The Bay Foundation gelei is om Suid-Kalifornië se kelpwoude te herstel, en hy het sedertdien pers egels in massas doodgemaak.

"Ons gaan af met geologiehamers en slaan dit stukkend," sê Herzik. Hul benadering is nie besonder hoëtegnologies nie, maar dit werk.

Tot op hede het Herzik en die ander projekdeelnemers (insluitend bioloë, vissers en gemeenskapsvrywilligers) 3,3 miljoen pers egels doodgemaak, wat 142 000 vierkante meter seebodem van die diere skoongemaak het. As gevolg hiervan het die kelp teruggespring.

Die Bay Foundation se kelp-herstelprojek, wat in 2013 begin is, is die grootste van sy soort. Uitvoerende direkteur en mariene bioloog Tom Ford sê die projek se doelwit is om meer as 600 000 vierkante meter seebodem van Kalifornië se Palos Verde-skiereiland (net suid van Los Angeles) te herstel deur die persegelskonsentrasie van soveel as 70 egels per vierkante meter te verminder. tot net twee. Na twee jaar sê Ford dat opvolgmetings van die bevolkings van verskeie mariene spesies wat op die kelp-ekosisteem staatmaak, bewys hul pogings werk.

Herzik stem saam dat die pers egeluitstorting 'n dramatiese effek gehad het. "Ons kan nie eers die gebiede herken waarin ons 'n paar kort jare gelede begin het nie," sê hy. "Dit is 'n heeltemal lewensbelangrike, volwasse kelpbos. Dit is vol lewe, en voorheen was die dorre soos maanlandskappe.”

Kelp groei waar koue, vlak, voedingryke water 'n rotsagtige seebodem bedek. Die geelbruin alge word gereeld tot 35 meter hoog, en bied kos en skuiling vir meer as 800 spesies. Maar soos in Suid-Kalifornië, krimp baie van die wêreld se kelpwoude.

Oor die afgelope eeu het talle oorsake—insluitend waterbesoedeling, afname in egels roofdiere veroorsaak deur oorjag, en klimaatsverandering—het veroorsaak dat die kelpblaadjie in Palos Verde-skiereiland met 75 persent gekrimp het. Die kelp-herstelprojek is nog in die vroeë dae in terme van die herwinning van daardie gebied, maar aanvanklike verslae is belowend. Die navorsers het bevind dat kelp by twee herstelgebiede 100 tot 1 000 keer digter is as voorheen.

Die kelp se vinnige herstel, sê Ford, word aangedryf deur die alge se verstommende vermoë om voort te plant en te groei. Jong kelp, "net een sel, is by die triljoene daar buite na 'n goeie voortplantingseisoen, so vervanging van volwassenes deur die volgende generasie is vinnig en omvattend," sê hy. Reuse-kelp groei ongelooflik vinnig, tot 'n halwe meter per dag. En met die kelp se herstel, het die navorsers die terugkeer gesien van aanwyserspesies, soos alge, wat onder die kelp-afdak leef, en vinvisse soos kelpbas.

Ford sê hierdie vroeë waarnemings is so positief dat hy navrae van wetenskaplikes, natuurbewaarders, hulpbronbestuurders en vissermanne van so ver as Japan, Noorweë, Nieu-Seeland, Australië en Kanada gerig het, wat op soek is na hul resultate.

Herstel is egter nie so eenvoudig soos om miljoene pers see-egels dood te maak nie. Agter die skerms was politieke onderhandelinge en pogings om die vissersgemeenskap te betrek belangrike fasette van die projek.

Om met egelvissers saam te werk was iets van 'n staatsgreep. Histories was vissers taai, doeltreffende lobbyiste om die egels te bewaar, selfs ten koste van die kelpwoude. Geval in punt: in die 1980's het egelvissers die Verenigde State se Kongres aangemoedig om 'n "otter-uitsluitingsone" in Suid-Kalifornië te skep om hierdie roofdier se tol op egelbevolkings te verminder, ten spyte van die feit dat otters 'n beskermde spesie is. (Die beleid is in 2012 deur die US Fish and Wildlife Service herroep omdat baie otters tydens deportasie dood is.)

Ford het twee strategieë gebruik om egelvissers aan boord te kry. Eers het hy hulle betaal. Boonop het hy en die span by The Bay Foundation 'n studie gedoen wat getoon het dat rooi-egels groter gonades (tot 484 persent groter) in kelpwoude as in dorretjies het, wat beteken dat kelp-herstel vissers se oes sal verbeter.

Soos baie vissers, sê Herzik hy was aanvanklik versigtig om met wetenskaplikes te werk. Maar nou is hy geïnspireer deur die werk. "Nadat ons gelukkig genoeg was om 'n gesin uit die oorvloed van die see groot te maak, was hier 'n geleentheid om terug te gee," sê hy.

Regstelling: 'n Vorige weergawe van hierdie artikel het gesê dat see-otters in die 1980's 'n beskermde bedreigde spesie was. See-otters het volgens die IUCN eers in 2000 "bedreigde" status verkry.


Sekwestering van kweekhuisgasse

Aangesien die konsentrasie van kweekhuisgasse soos koolstofdioksied teen ongekende tempo toeneem, is mense daarop gefokus om die hoeveelheid koolstofdioksied wat ons in die lug plaas, te verminder. Terwyl die doeltreffendste manier om dit te doen is deur koolstofvrystellings te verminder, dink kenners toenemend dat dit nie genoeg sal wees nie. Volgens die Interregeringspaneel oor Klimaatsverandering, die toonaangewende internasionale liggaam oor klimaatsverandering, moet ons aktief koolstofdioksied uit die atmosfeer verwyder of sekwestreer om negatiewe koolstofvrystellings te bereik en klimaatkatastrofe te voorkom. Teen 2050 moet ons beplan om netto nul-vrystellings te hê, wat beteken dat alle koolstofvrystellings deur koolstofverwydering gebalanseer moet word.

Een manier om koolstofdioksied te sekwestreer is die gebruik van biologie. Wanneer plante soos bome fotosinteer en groei, word koolstof in die vorm van koolstofdioksied uit die atmosfeer verwyder en in biomassa omgeskakel, soos 'n tak of blaar op 'n groeiende boom. Alhoewel bome koolstof stoor, is hierdie berging kwesbaar aangesien ontbossing of woudegradasie hierdie koolstof terug in die atmosfeer vrystel, wat die voordele ongedaan maak. Wanneer ons aan koolstofsekwestrasie dink, moet ons op permanente oplossings fokus.

Kusekosisteme sekwestreer verbasend groot hoeveelhede koolstof weg – hulle kan tot 20 keer meer koolstof per akker as landwoude sekwestreer. Mariene plante wat bydra tot hierdie koolstofsekwestrasie, soos mangroves en seegras, leef in ryk grond. Wanneer hierdie plante doodgaan, word van die blare, takke, wortels en stingels onder water in die grond begrawe – en as gevolg van lae suurstofkonsentrasies onder water, kan die plantmateriaal vir dekades of langer begrawe bly voordat dit afbreek en koolstofdioksied vrystel. Ongelukkig, omdat die koolstof naby die kus gestoor word, kan dit maklik deur afloop, menslike aktiwiteit of storms versteur word en gouer in die atmosfeer vrygelaat word as wat dit andersins sou wees.


Hoeveel reuse-kelp is daar per vierkante meter? - Biologie

As jy al ooit langs die Kaliforniese kus gestap het, moes jy waarskynlik om klompe seewier navigeer. Verstaan ​​​​dit: voordat dit deur die branders opgegooi is en op die strand gelaat is om droog te word, was daardie skynbare jetsam deel van 'n majestueuse onderwaterwoud net langs die kus.

Sterk golwe, wat dikwels deur winterstorms aangevuur word, kan groot kolle buitelandse kelp verwyder en dit op die strande van Kalifornië neersit. (Foto met vergunning van Chad King / NOAA MBNMS)

Reuse-kelpwoude is een van die Aarde se mees produktiewe habitatte, en hul groot verskeidenheid plant- en dierspesies ondersteun baie visserye regoor die wêreld. Die kelp, of Macrocystis, waaruit hierdie onderwaterwoude bestaan, is werklik reusagtig. Hulle is die wêreld se grootste mariene plante en word gereeld tot 35 meter (115 voet) hoog, die grootste reuse-kelp op rekord was 65 meter (215 voet) hoog. Duikers het swem deur volwasse kelpwoude vergelyk met stap deur rooiboswoude.

Anders as rooibosse, is reusekelp kortstondig. Hulle leef hoogstens sewe jaar, en dikwels verdwyn hulle voor dit as gevolg van winterstorms of oorbeweiding deur ander spesies. Soos vissermanne weet, kan reuse-kelpwoude verskyn en verdwyn van seisoen tot seisoen, van jaar tot jaar. Maar is daar 'n langtermyn-tendens of siklus by die werk?

'n Paar jaar gelede was Jarrett Byrnes in 'n bietjie van 'n verknorsing oor hierdie verdwynende woude. As deel van sy nadoktorale navorsing aan die Universiteit van Kalifornië&ndashSanta Barbara (UCSB), het hy reusekelp bestudeer by vier Nasionale Wetenskapstigting-befondsde terreine langs die kus. Sedert 2000 het bioloë hierdie Langtermyn Ekologiese Navorsing (LTER) webwerf gebruik om maandeliks in situ metings van reuse kelp. Maar Byrnes en sy kollegas het gevind dat hulle dikwels nie in die winter metings kon doen nie, want rowwe see het die duik onveilig gemaak.

Kelp is die rooibosse van die see. Die wêreld se grootste mariene plante groei gereeld tot 35 meter (115 voet) hoog. (Foto en kopieer Phillip Colla / Oceanlight.com)

& ldquoStorms verwyder nogal 'n bietjie van die blaredak in die winter. Soms verwyder hulle selfs hele woude as die storms groot genoeg is, & rdquo Byrnes verduidelik. &ldquoMaar om in die winter gereeld by daardie terreine te kom, raak baie uitdagend.&rdquo Die meeste van die duik moes tot die somer wag, en toe het die kelp grootliks herstel of verander, wat dit moeilik maak om te meet hoeveel skade die storms aangerig het.

Om sake te bemoeilik, het kelpwoude verskillende seisoenaliteit, afhangende van waar hulle is. Byvoorbeeld, die woude langs die Sentraal-Kalifornië-kus is op hul maksimum grootte in die herfs in Suid-Kalifornië, hulle bereik dikwels hul hoogtepunt in die winter en lente. Hoe kan hierdie dinamiese habitatte meer gereeld gemonitor word sonder om duikers in gevaar te stel?

Kyle Cavanaugh, destyds 'n UCSB-gegradueerde student, het 'n idee gehad. &ldquoHierdie woude verander so vinnig en op 'n verskeidenheid verskillende tydskale&mdashmaande tot jare tot dekades&mdashso ons het 'n lang rekord met konsekwente, herhaalde waarnemings nodig gehad,&rdquo Cavanaugh gesê. Hy het 'n metode uitgedink om Landsat-satellietdata te gebruik om kelpwoude te monitor.

'n Paar dinge het Landsat 'n ooglopende hulpbron gemaak. Sedert die 1970's het die satelliete 'n gereelde insamelingskedule (twee keer per maand). Hul data en beelde word deur die Amerikaanse Geologiese Opname bestuur en word betroubaar gestoor in 'n argief wat meer as veertig jaar terug dateer. En Landsat&rsquos-beelde word gekalibreer, of gestandaardiseer, oor verskillende generasies satelliete, wat dit moontlik maak om data wat oor 'n paar dekades versamel is, te vergelyk.

Landsat 8 kan naby-infrarooi golflengtes van lig opspoor wat dit makliker maak om aflandige kelpwoude op te spoor. (NASA Earth Observatory-beeld deur Mike Taylor, met behulp van Landsat-data van die U.S. Geological Survey)

Landsat meet die energie wat op baie verskillende golflengtes van die Aarde gereflekteer en uitgestraal word. Deur te weet hoe kenmerke op Aarde energie by sekere golflengtes reflekteer of absorbeer, kan wetenskaplikes veranderinge aan die oppervlak karteer en meet. Die belangrikste kenmerk vir die kelp-navorsers is Landsat&rsquos naby-infrarooi band, wat golflengtes van lig meet wat net buite ons visuele reeks is. Gesonde plantegroei weerspieël sterk naby-infrarooi energie, so hierdie band word dikwels in plantstudies gebruik. Water absorbeer ook baie naby-infrarooi energie en reflekteer min, wat die band besonder goed maak vir die kartering van grense tussen land en water.

&ldquoDie naby-infrarooi is die sleutel vir die identifisering van kelp uit omliggende water,&rdquo Cavanaugh verduidelik. &ldquoSoos ander soorte fotosinteterende plantegroei, het reusekelp hoë reflektansie in die nabye infrarooi. Dit laat die kelp-afdak regtig uit die omliggende water uitstaan.& Rdquo

Vir Byrnes was die benadering 'n deurbraak: &ldquoDit het beteken dat ons die woude kon sien wat ek ontleed het net nadat storms hulle getref het.&rdquo

Groei vinnig en hou vas

Reuse-kelp is vinnige groeiers, en hulle floreer in koue, voedingstofdigte waters, veral waar daar 'n rotsagtige en vlak seebodem is (5 tot 30 meter of 15 tot 100 voet). Hulle heg aan die seebodem met klein wortelagtige strukture (haptera) wat ook, gepas genoeg, 'n houvas genoem word. Die houvas ondersteun 'n steel, of steel, en blaaragtige lemme wat dryf danksy luggevulde sakke (pneumatosiste). Die blaarblare skep digte drywende afdakke op die wateroppervlak, maar hierdie massiewe plante maak staat op houvas van skaars 60 sentimeter (24 duim) breed om hulle gewortel en lewendig te hou.

Gegewe die regte balans van toestande, kan reusekelp soveel as 50 sentimeter (1,6 voet) per dag groei, en hierdie robuuste groei maak dit moontlik vir kelpblare om kommersieel geoes te word. Reuse-kelp is sedert die vroeë 1900's uit die waters van Kalifornië gepluk, en hulle het lank in produkte soos roomys en tandepasta verskyn. Op die industrie se hoogtepunt kon groot skepe wat grassnyeragtige masjinerie gebruik meer as 200 000 nat ton jaarliks ​​oes.

Kelp fronds skep digte drywende afdakke naby die wateroppervlak. Kelp word al vir 'n eeu geoes vir kommersiële produkte wat ook moeilikheid vir bootskroewe veroorsaak. (Foto met vergunning van Chad King / NOAA MBNMS)

&ldquoDie satelliet kon beslis die uitwerking van oes sien, maar die kelp-herstel was baie vinnig,&rdquo het gesê Tom Bell, 'n UCSB-navorser en medewerker met Byrnes en Cavanaugh.

Vandag word net 'n paar duisend ton reuse-kelp elke jaar geoes, sommige met die hand en sommige deur meganiese stropers. Die kelp kan nie laer as 4 voet onder die wateroppervlak gesny word nie, en hierdie volhoubare oes is die ekwivalent van mense wat 'n haarsny kry. Studies het getoon dat negatiewe effekte weglaatbaar is, hoewel sommige vispopulasies tydelik verplaas word.

Reuse-kelp floreer in koue, voedingstofdigte water, veral waar daar 'n rotsagtige, vlak seebodem is. Die Kaliforniese kus bied ideale habitat. (NASA Earth Observatory-beeld deur Mike Taylor, met behulp van Landsat-data van die U.S. Geological Survey)

Wetenskaplikes het jare lank gedebatteer of dit die beskikbaarheid van voedingstowwe of weiders (nie menslike stropers nie, maar see-egels) was wat die meeste invloed op kelpbos se gesondheid, grootte en langlewendheid gehad het. Nadat hy Landsat gebruik het om na langtermynneigings te kyk, en daardie neigings met bekende verskille tussen Sentraal- en Suid-Kalifornië-waters vergelyk het, het Cavanaugh en LTER-hoof Daniel Reed gevind dat 'n derde krag-&mdashgolfversteuring&mdash die koningskap van kelp-dinamika was. Sterk golwe wat deur storms gegenereer word, ontwortel die kelp uit hul houvas en kan die woude baie meer verwoes as enige weiding.

Kelp Navorsing vertak

Toe reuse-kelp Byrnes en Cavanaugh die eerste keer by UCSB bymekaargebring het, was hul werk grootliks op Kalifornië gefokus. Die data wat hulle van die LTER-studiewebwerwe van Santa Barbara ingesamel het, het 'n geweldige hulpbron vir kelpnavorsers geword. Maar daardie werk het vier afsonderlike liggings gedek vir 'n spesie wat oor die hele wêreld voorkom.

Reuse-kelp kan oral groei waar daar koue, vlak, voedingryke water en 'n rotsagtige seebodem is. Toestande vir kelpgroei was histories ideaal langs die weskus van Noord-Amerika, sowel as Chili, Peru, die Falkland-eilande, Suid-Afrika, en rondom Australië, Nieu-Seeland en die sub-Antarktiese eilande.

Deesdae is die toestande egter meer en meer dikwels minder ideaal. Klimaatsverandering het 'n trifekta van kelp-gesels meegebring: warmer waters met minder voedingstowwe nuwe indringerspesies en hewige storms.

Gegewe die regte balans van toestande, kan reusekelp soveel as 50 sentimeter (1,6 voet) per dag groei. (Foto en kopieer Phillip Colla / Oceanlight.com)

Na 'n onlangse vergadering oor kelpwoude en klimaatsverandering, het Byrnes, Cavanaugh en ander kollegas begin om al die beskikbare kelpwouddata van regoor die wêreld te konsolideer. Hulle wou 'n stap neem om te verstaan ​​hoe klimaatsverandering kelp wêreldwyd beïnvloed, maar hulle het vinnig ontdek hulle het 'n yl lappieskombers van inligting.

Byrnes is met 'n gedagte getref. Hulle het Landsat gebruik om hul studies oor tyd uit te brei, so hoekom nie Landsat gebruik om hul studies oor die wêreld uit te brei nie? Kan Landsat gebruik word om globale neigings in kelpbos omvang vas te stel? Die antwoord was ja, maar die probleem was oogappels.

Anders as navorsing oor landplantegroei&mdash, wat Landsat-data en kragtige rekenaarverwerkingsskikkings gebruik om wêreldwye berekeninge te maak&mdash, vereis dit handmatige interpretasie. Terwyl kelpwoude na die menslike oog in naby-infrarooi beelde verskyn, kan rekenaars wat numeries na die data kyk, kelpkolle met landplantegroei verwar. Programme en gekodeerde logika wat waterplantegroei van landplantegroei skei, kan verwar word deur dinge soos wolke, sonbrand en seeskuim.

Natuurlike kleur (bo) en naby-infrarooi (onder) beelde van Landsat 8 wys die kelp-ryk water rondom Kalifornië & rsquos Kanaal-eilande. Wolke, sonbrand en seeskuim maak dit moeilik vir rekenaarprogramme om die ligging van woude op te spoor. Tot dusver werk menslike oë beter. (NASA Earth Observatory-beeld deur Mike Taylor en Jesse Allen, met behulp van Landsat-data van die U.S. Geological Survey)

&ldquoI&rsquove het baie, baie jare na satellietbeelde gestaar en probeer om vorendag te kom met nuwe maniere om die kelp-sein uit daardie beelde te onttrek, en dit is baie tyd en werk intensief, & rdquo gesê Cavanaugh, nou gebaseer by die Universiteit van Kalifornië & ndashLos Angeles. &ldquoMaar outomatiese klassifikasiemetodes lewer nog net aanvaarbare vlakke van akkuraatheid.&rdquo

Byrnes, nou gebaseer aan die Universiteit van Massachusetts&ndashBoston, het besef dat die beste manier om globale kelpveranderinge te bestudeer, was om na burgerwetenskaplikes te wend. Byrnes en Cavanaugh het 'n wetenskapspan saamgestel en aangesluit by Zooniverse, 'n groep wat professionele wetenskaplikes met burgerwetenskaplikes verbind om te help om groot hoeveelhede data te ontleed. Die resultaat was die Floating Forests-projek.

Kry hulp van 'n paar duisend vriende

Die Floating Forest-konsep gaan alles daaroor om meer oogballe op Landsat-beelde te kry. Burgerwetenskaplikes&mdash wat via die internet gewerf is&mdashare het opdrag gegee oor hoe om vir reuse-kelp in satellietbeelde te jag. Hulle word dan Landsat-beelde gegee en gevra om enige reuse-kelpkolle wat hulle vind, te skets. Hul bevindings word gekruis met dié van ander burgerwetenskaplikes en dan aan die wetenskapspan oorgedra vir verifikasie. Die grootte en ligging van hierdie woude word gekatalogiseer en gebruik om globale kelp-neigings te bestudeer.

Benewens die ondersoek van die Kaliforniese kus, wat Byrnes en Cavanaugh goed ken, het die Floating Forests-projek ook gefokus op die waters rondom Tasmanië. Tom Bell en medewerkers in Australië en Nieu-Seeland het die afgelope paar dekades dramatiese afnames in reuse-kelpwoude daar opgemerk. Die afname was so vinnig en omvangryk dat reusekelp nou eers in geïsoleerde kolle gevind word.

Aan die ooskus van Tasmanië het 95 persent van die kelp sedert die 1940's verdwyn. Valskleur Landsat-beelde van September 1999 (bo) en September 2014 (onder) verskaf bewyse van onlangse kelpwoudversteuring. (NASA Earth Observatory-beeld deur Mike Taylor, met behulp van Landsat-data van die U.S. Geological Survey)

Aan Tasmanië se ooskus het 95 persent van die kelp sedert die 1940's verdwyn. Die verlies was so groot dat die Australiese regering Tasmanië se reuse-kelpwoude as 'n bedreigde ekologiese gemeenskap gelys het, die eerste keer dat die land beskerming aan 'n hele ekologiese gemeenskap gegee het. Die verlies is so verstommend, want dit was 'n plek waar kelpwoude eens so dig was dat hulle vermelding op seekaarte verdien het.

Koel, subarktiese waters het Tasmanië se ooskus eens gebad, maar warmer waters (sowat 2,5ºC (4,3ºF) warmer) het baie indringerspesies meegebring wat aan reusekelp smul. Om die saak te vererger, het die oorbevissing van kreef 'n belangrike roofdier van die langdorings see-egels (wat kelp vreet) verwyder. Die ekosisteem se nuwe beskermde status kan help om oorbevissing te bekamp en die kreef te herstel, wat sal help om die bedreiging van see-egels te verminder.

Hierdie grafiek van die Amerikaanse hidrografiese diens van 1925 toon Prosserbaai, Tasmanië, en die verspreiding van reusekelp. (Bron: Edyvane et al, 2003)

Deur Landsat te gebruik om die kelpwoude te monitor en neigings te vestig, kan meer lig werp op wat van Tasmanië af gebeur. &ldquoOns glo die data van Floating Forests sal ons in staat stel om die oorsake van hierdie dalings beter te verstaan,&rdquo het Cavanaugh gesê.

Vanaf November 2014 het meer as 2 700 burgerwetenskaplikes by Byrnes en Cavanaugh aangesluit om kelp in 260 000 Landsat-beelde te soek. Alles saam het die burgerwetenskaplikes nou meer as een miljoen kelp-klassifikasies gemaak. Die reaksie het verwagtinge oortref, en die projek is vinniger uitgebrei as wat oorspronklik beplan is.

Daar is reeds 'n ontdekking gemaak. ’n Burgerwetenskaplike het ’n groot stuk reusekelp op die Cortez-bank gevind, ’n onderwater-seeberg sowat 160 kilometer (100 myl) van die kus van San Diego af. Terwyl reusekelp op hierdie onderwater eiland wat op sommige punte binne voet van die oppervlak kom, in die verlede deur duikers en vissermanne gedokumenteer is, was die volle omvang van die kelpbeddings onbekend.

’n Burgerwetenskaplike het satellietbewyse gevind van ’n afgeleë kelpwoud wat voorheen net aan duikers en plaaslike vissermanne bekend was. (NASA Earth Observatory-beeld deur Mike Taylor, met behulp van Landsat-data van die U.S. Geological Survey)

&ldquoDie eerste paar maande van Floating Forests was 'n groot sukses, en ons is hoopvol dat ons binnekort die projek na ander streke sal kan uitbrei,&rdquo Cavanaugh gesê. &ldquoOns uiteindelike doelwit is om al die kuslyne van die wêreld te dek wat reuse-kelpwoude ondersteun.&rdquo

Om te leer hoe om aan die Floating Forests-projek deel te neem, besoek hul webblad.


Hoeveel reuse-kelp is daar per vierkante meter? - Biologie

"Wees 'n baas - Help die albatros"

Kelp PBC se Earth Hero Honoree 2019

Elke jaar kies ons 'n dier of 'n skepsel om die eerbewys van die jaar te wees. Ons het die afgelope paar jaar ons gemeenskap opgevoed oor die seesterre, dolfyne, haaie, skilpaaie ens. Ons is bly dat ons die kelp vir 2019 gekies het, want dit is diep gekoppel aan die see-otters en die gesondheid van ons oseane. Hieronder vind u algemene inligting oor hierdie ongelooflike seewier.

'n Onderwaterbos

Kelps is groot bruin alge seewier wat die orde Laminariales vorm. Daar is ongeveer 30 verskillende genera.

Kelp groei in “onderwaterwoude” (kelpwoude) in vlak oseane, en word vermoedelik in die Mioseen, 23 tot 5 miljoen jaar gelede, verskyn. Die organismes benodig voedingsryke water met temperature tussen 43 en 57 ° F. Hulle is bekend vir hul hoë groeikoers & # 8211 die genera Makrosistis en Nereocystis kan so vinnig as 1,5 voet per dag groei en uiteindelik 100 tot 260 voet bereik.

In die meeste kelp bestaan ​​die tallus (of liggaam) uit plat of blaaragtige strukture bekend as lemme. Lemme ontstaan ​​uit langwerpige stamagtige strukture, die stipes. Die houvas, 'n wortelagtige struktuur, anker die kelp aan die substraat van die see. Gasgevulde blaas (pneumatosiste) vorm aan die basis van lemme van Amerikaanse spesies, soos bv. Nereocystis lueteana, (Mert. & Post & Rupr.) om die kelp lemme naby die oppervlak te hou.

Wat maak ons ​​kelp dood?

Ons oseaniese woude is tans onder beleg van 'n kragtige mengsel van klimaatafwykings, siektes en predasie wat gelei het tot afnames in kelpwoude wat nie in dekades gesien is nie.
In hulle plek, groot “urchin barrens” van kaal rots skoon gepluk deur rondloper grazers. Hierdie versonke ekwivalente van woud-uitsnyde darm die komplekse verhoudings wat 'n gesonde ekosisteem onderhou.

Klimaatverandering
Verswak deur stygende oseaantemperature en aggressiewe storms, was kelpwoude reeds benadeel toe navorsers begin sien het dat egelbevolkings in 2015 toeneem.

Oorbevissing
Oorbevissing van nabykus-ekosisteme lei ook tot die agteruitgang van kelpwoude. Herbivore word vrygestel van hul gewone bevolkingsregulering, wat lei tot oorbeweiding van kelp en ander alge. Dit kan vinnig lei tot onvrugbare landskappe waar slegs 'n klein aantal spesies kan floreer.

Maar die see-otters eet egels, reg?

Tradisioneel het Kalifornië se ikoniese see-otter ingespring om egelbevolkings in toom te hou. Otters voed op see-egels, wat weerhou dat hulle op kelp oorbewei. Sonder otters is die implikasie dat ons enigsins sou ophou om kelpwoude te hê.
So, wat gebeur wanneer otters vergeet net wat op die spyskaart is?
Op dieselfde manier as wat jy baie dinge kan eet, maar dalk verkies om pizza te eet, is dit bekend dat otters algemene in hul dieet is. Maar individue het spesifieke voorkeure wat van moeder na hondjie oorgedra word.

James Watanabe is 'n dosent by Hopkins Marine Station, en hy was die eerste wat voorgestel het dat otters moontlik 'n "kulturele geheueverlies" ontwikkel het.
“Van die groot pols van werwing in die 70's, tot nou toe, toe die egels weer begin verskyn het, was daar drie generasies otters met 'n paar see-egels teenwoordig,” sê hy, “maar nie genoeg vir enige otter nie om te fokus op as die belangrikste deel van die dieet.”

Wat van 'n reuse-suigbuis?

Kommersiële see-egelduiker Jon Holcomb help om een ​​van verskeie pogings met ander duikers en die staat te koördineer om te help om die kelp terug te bring. Holcomb het 'n groot suigbuis gebruik wat 'n lughyser genoem word wat die pers egels van die klipperige bodem af na sy boot trek. Aan wal word sy egels deur 'n afvalverwyderingsmaatskappy opgetel en in kompos verander. Sedert Januarie het hy gesê dat hy ongeveer 120 000 egels versamel het uit 'n klein inham langs die dorpie Caspar, in Mendocino County, en hy hoop om nog 1,5 miljoen teen Julie te lewer. Sy doelwit is om pers egels uit klein gebiede te verwyder waar nog bulkelp oorbly.

"Ons wil 'n soort saadbank op hierdie plekke skep, sodat wanneer die omgewingstoestande weer gunstig word, die kelp dalk kan begin teruggroei," het Sonke Mastrup, die Kaliforniese departement van vis en natuurlewe se programbestuurder vir ongewerwelde visserye, gesê.

Sea Urchin Smashing Party Enige iemand?

Ontspanningsduikers – die meeste van hulle perlemoen-fanatici – dra by tot die poging, met planne om Ocean Cove, in Sonoma County, vanaf Mei skoon te maak, volgens die duiker Josh Russo, president van die Waterman's Alliance. Alhoewel sommige sportduikers egels stukkend geslaan het, sê Russo dat die duikers waarmee hy werk, die diere heeltemal uit die water sal verwyder. (Om egels te slaan oortree 'n staatswet wat die moedswillige vermorsing van mariene hulpbronne verbied.)

Staatsamptenare ondersteun Russo se plan, hoewel hulle nie verplettering sal toelaat nie. Volgens Mastrup oorweeg visserybestuurders dit sterk om die daaglikse persegelssakperk vir sportduikers van 35 egels tot 20 liter te verhoog – wat gelykstaande is aan 'n paar honderd diere.

Terwyl hulle ernstige uitdagings van skaal in die gesig staar, kan Kalifornië se egelbestrydende leër hoop neem in vorige ingrypings in ander streke wat 'n mate van sukses behaal het om egels in kelpbos te omskep.

In Suid-Kalifornië het 'n gekoördineerde poging om oorbevolkte egels met hamers uit te maak - waarvoor staatsamptenare 'n permit toegestaan ​​het - gewerk, hoewel ook op 'n baie klein skaal. Volgens Julie Du Brow, kommunikasie-direkteur van die Bay Foundation, het duikers met hamers 18 hektaar (44 hektaar) van 'n 60 hektaar (152 hektaar) uitgestrekte egels wat onvrugbaar is van die Palos Verdes-skiereiland na welige kelpwoud teruggeplaas. Oor vier jaar het hulle egelsdigthede van so hoog as 100 per vierkante meter tot net twee verminder.

Hoe jy die kelp kan help

Deur mariene besoedeling te stop, kan ons die kelpwoude beskerm.

Mariene bioloë het gevind dat die vermindering van voedingstofbesoedeling in mariene kus-omgewings moet help om kelpwoude te beskerm teen die skadelike gevolge van stygende CO2.

Hier is klein dingetjies wat jy kan doen om CO2 te verminder en die kelp te red:
– Saamry, fiets en stap meer
– Hergebruik, Verminder, Herwin en kompos
– Maak energiedoeltreffendheid 'n primêre oorweging wanneer jy 'n nuwe oond, lugversorgingseenheid, skottelgoedwasser of yskas kies
– Skakel ligte af wat jy nie gebruik nie en wanneer jy die vertrek verlaat. Vervang gloeilampe met kompakte fluoresserende of LED-gloeilampe
– Eet plaaslik-geproduseerde en organiese kos
– As jou dieet dit toelaat, probeer om beesvleis en suiwel te verminder
– Kom na ons Habitat Restoration-geleenthede om te leer oor inheemse plante en voeg sommige by jou tuin
– Sluit aan by ons strandopruimings om meer te wete te kom oor mariene puin en rommel
– Gebruik jou stem om jou kennis te deel


Hoeveel reuse-kelp is daar per vierkante meter? - Biologie

EK HET NET EEN keer 'N PERLEON GEHOU. Die reuse mariene slak, gepluk uit die wit laboratoriumtenk waaraan dit vasgegom was, het my hand vasgegryp asof hy aan die Kaliforniese seebodem net anderkant ons vashou. Ek het na sy oorvormige skulp gekyk, bedek met 'n sterrestelsel van alge - sy tentakels wat die bowaterwêreld ondersoek, sy oë wat nuuskierig rondbeweeg in hul buisvormige voetstukke. Na 'n paar oomblikke het sy greep stywer geword, en die groewe aan sy onderkant, wat soos 'n palm of 'n vingerafdruk lyk, het die lyne op my eie hand begin invul. Gou het dit gevoel asof daar geen spasie tussen ons oor was nie.

Wanneer ek maande later hierdie ervaring terugdink, is dit asof die perlemoen steeds in my hand is, koel soos seewater, maar lewendig, en polsend, en my net so vasgehou het as wat ek dit vasgehou het. Die gevoel, so byna tasbaar, raak my soos 'n spook-ledemaat.

Vir jare het perlemoen ernstige agteruitgang in Kalifornië. Terwyl perlemoenskulpe voortduur, in sypaadjiebanke gevorm, op wegwysers vasgespyker en op ontelbare stamgrafstene gelê word, bly die diere self - waarvan sewe spesies in Kalifornië se waters woon - almal steeds minder uit hul kelpboshuise. This stark reality is the result of decades of abalone overharvesting and climate disruption, the impacts of which have been amplified by trophic cascades.

When I held that living abalone, I felt more than just its grip. I felt the fastening of myself to another being. For a moment, I became a link between the stories of my species and those of another.

Abalone stories span the entire length of human habitation in California, and hold artists, surfers, scientists, watermen, Native tribes, and countless other coastal cultures in their breadth. Losing abalone would mean losing one of California’s oldest and most widespread connections to the natural world.

We are now at an inflection point in the history of these mollusks, where nascent restoration efforts are struggling against various ecological, technological, and cultural barriers to recovery. But a cohort of researchers is pushing through these obstacles, devoted to finding out if abalone can recover, or if their future is leaning inexorably toward extinction in the wild.

THE COMPLICATED HISTORY of abalone in California requires a good deal of time to recount, says Dr. Paul Dayton. His colleague at the Scripps Institution of Oceanography in San Diego, Dr. Ed Parnell, agrees, adding that the story sounds better between bites of freshly-baked pie. And thus, we find ourselves in the so-called “Pie Room” at Scripps, where assorted office chairs line a weathered wooden table covered with plates, forks, and flecks of light scattering off the midday Pacific as it dances beside La Jolla.

Illustration by Dominick Leskiw.

Scripps is the first of nearly 30 stops my advisor, Benjamin Neal, an assistant professor of environmental studies at Colby College, his two young children, and I will make on a 600-mile road trip up the California coast from La Jolla to just north of Bolinas, tracking down abalone devotees from all walks of life. While opening the box of peach pie, then the apple, I mention the particolored campervan that will rattle us along to each of these stops. Parnell and Dayton laugh, saying they could see it from a mile away.

Dayton, professor emeritus at Scripps, can boast a lifetime’s worth of experience in ocean research, much of it spent beneath the waves. He can also describe, in remarkable detail, the sea as it was many eras before his own. “Let’s go back to pre-contact with humans,” he says, to around 15,000 years ago, when the waters off Southern California were bulging with kelp, fish, sea otters, and yes, abalone, too. Though not without natural fluctuations, Dayton notes, this late-Pleistocene kelp forest ecosystem was well-balanced.

Then, around 7,000 years ago, Native peoples began harvesting abalone- and urchin-munching otters for meat and fur. Released from some natural predatory pressure, abalone and sea urchin populations began to swell. Beginning in the 1500s, the Spanish colonists devastated Indigenous populations with violence and diseases, and, along with other Europeans, took over the fur trade. Abalone populations swelled further.

‘One reason the abalone and everyone are in trouble is there’s no food.’

Around the time California gained statehood in 1850, the snails could safely mosey out from under protective rocks and crevices to find more kelp and other food. With ample abalone out and about, voracious sea urchins — which, when unchecked, overwhelm and strip the seafloor clean — couldn’t stick their tubular feet to the ground. “The abalone outcompeted the urchins for space,” Dayton says, describing how one of the abalone’s key ecological roles is placing a check on urchin populations.

As abalone gained a stronger foothold in the Pacific, rumors of gold brought shiploads of people to California, including Chinese immigrants seeking to escape the political unrest, poverty, and opium addictions plaguing their homeland. When gold became scarcer, these immigrants were scorned by white miners and forced into more marginal occupations such as coastal fishing. Soon, they discovered the remarkable abundance of abalone that had proliferated in the absence of harvesting by Indigenous peoples and otters. Chinese fishers used traditional techniques to gather, dry, and export abalone meat to Asia — particularly black abalone, which was easiest to gather from intertidal aggregations — and also began selling the animals’ exquisite shells as ornamentation. By 1879, this fishery had already reached its peak.

Within a few years, however, xenophobia and discriminatory laws put an end to Chinese fishing operations. Japanese and Euro-American divers seized the abalone industry in the early 1900s and used new hardhat technologies to harvest subtidal species from previously inaccessible depths. Small boats could overfill and nearly sink themselves with two tons of abalone per dive, plucking them away from living assemblies up to a dozen animals thick. When anti-Japanese sentiment spiked around the Second World War, Euro-Americans took over the industry, now with more mobile and efficient scuba gear, despite early warnings of abalone decline.

As thousands of large adult abalone were pried off the seafloor, divers were noticing more and more urchins crawling about. That’s because all this time, as abalone were declining due to overharvesting, so too were moray eels, lobsters, sea bass, and other kelp forest animals that helped maintain the ecosystem’s balance.

In the 1990s, as their numbers dwindled drastically, fisheries for each abalone species began to close, one after the other. By the turn of the century, all that was left was a strictly regulated, free-dive only recreational harvest of red abalone along the intimidating Northern California coast. Then, in 2018, that fishery closed, too — and for the first time in the thousands of years of human occupation of California, no wild abalone could be legally harvested anywhere along the coast.

In late 2018, the statewide moratorium was extended to 2021. But it might have come too late. By then, all seven species were struggling to hang on. White abalone and black abalone had already been listed as federally endangered, and pinto, pink, and green abalone had been listed as “species of concern.” Flat abalone populations contracted to the point where the species was no longer common in California waters, and red abalone became more abundant on abalone aquaculture farms than in the wild ocean.

DAYTON EXPLAINS THAT, fundamentally, abalone faced a population density problem. As “broadcast spawners” — animals that breed by casting sperm and eggs out into the sea — abalone need to be within mere meters of each other for successful fertilization. Intense harvesting broke up the aggregations of abalone that were key to their reproduction. Any remaining large, fecund individuals are now effectively sterile given the ever-widening distance between mates.

One of the abalone’s key ecological roles is placing a check on sea urchin populations. When left unchecked, urchins can overwhelm and strip the seafloor and kelp forests clean, as is happening now in California’s coastal waters. Photo by Michael Zeigler / Istockphoto.

Overfishing of other kelp forest species like black sea bass and other large-bodied predatory fish hasn’t helped either. Octopus — another major source of abalone mortality — have proliferated in the absence of predators. Diseases, too, such as the nefarious withering syndrome that affects abalones’ digestive organs, periodically kill off enormous portions of abalone populations. Moreover, carpets of purple urchins, sometimes with up to 100 individuals per square meter, eat every kelp in sight, since abalone no longer occupy great swaths of seafloor from which to exclude them. “I’m worried about the kelps,” Dayton says. “One reason the abalone and everyone are in trouble is there’s no food.”

And then there’s climate change, which further threatens the kelp forests on which abalone depend. In Southern California, intensifying El Niño and “warm blob” events bring unusually high ocean temperatures, and limit the dissolved nutrients that Macrocystis , commonly known as giant kelp, needs for growth. Farther north, when Nereocystis , or bull kelp, aren’t being chewed down by urchins, they’re likely to be torn away by increasingly harsh winter storms.

“It’s a sad story of serial screwing-up of the ecosystem,” Parnell says wistfully. “You have a trend where abalone food supply is decreasing at the same time that they’ve been hammered by warm water, associated diseases, and overharvesting.”

I look from the empty pie boxes to Dayton and Parnell. We sit quietly for a moment as the sea outside shifts in the afternoon sun. Parnell leaves for a bit and comes back with a handful of small shells, some numbered, others half-covered in wax — remnants of a juvenile abalone recovery project. This experiment, long abandoned, served as a predecessor to what is quickly becoming one of the most important components of abalone restoration today — outplanting.

A SMALL, SUN-WEATHERED building situated amidst the ceaseless industrial stir of Terminal Island — a primarily artificial slab of land more or less divided between the Port of Los Angeles and the Port of Long Beach — seems like a strange place to raise endangered marine invertebrates. Yet, that is exactly what Director of Marine Operations Heather Burdick and her team at the Santa Monica Bay Foundation have set out to do.

“We’ve been doing captive spawning here in our lab with greens and reds, and now we’re starting to work with white abalone,” Burdick announces from the parking lot, over a thrum of shipping trucks and ocean freighters. She leads us into her lab, which burbles with the sound of filters, while water in trough-shaped tanks glints with UV-light from overhead. Peering around, I see a handful of tiny pink and olive shells clinging to the tank walls. These are critically endangered baby white abalone, Burdick’s colleague, Armand Barilotti, says.

These young mollusks are the result of a hydrogen peroxide spawning method that has worked to induce in-house reproduction nearly a dozen times in the “Ab Lab.” Essentially, an enzyme naturally activated by low levels of hydrogen peroxide causes the abalone to produce the reproductive hormone prostaglandin endoperoxide, and spawn. This method has enabled semi-predictable spawning in the lab and has generated juvenile white abalone for eventual release in the wild. Leaning in to look at the minuscule animals attached to the walls of the tanks, Burdick goes on to mention a newer “deck spawning” technique that is also already being practiced. This method involves spawning adult abalone aboard research vessels, releasing them immediately afterward, and going on to raise the larvae back in the lab. In other words, researchers facilitate reproduction while reducing disturbance to wild adult abalone, who don’t ever have to leave the vicinity of their home reefs. Efforts akin to those made by the Bay Foundation are now in motion across the state, all with the goal of raising abalone in captivity, for eventual outplanting back into the sea.

“There are so many people involved, and everybody sort of has a niche,” Burdick says. “We’re going to be the staging center for outplanting. Bodega Bay [in Northern California] is leading the captive breeding program, and then you have people at NOAA going out and trying to find existing white abalone so we can learn more about their habitats.”

Most abalone in labs have never seen a wild environment, so researchers don’t know how they will react to threats once outplanted. Photo by Dominick Leskiw.

These efforts are an important start for abalone restoration, and they are backed by passion and momentum. But the program is still nascent, and it lacks the funding required to conduct operations consistently and on a scale large enough to combat the dozens of confounding elements working against abalone recovery today.

Not to mention that dependably breeding and raising abalone in captivity is no easy feat. For one thing, abalone reproductive cycles can be difficult to time properly in lab settings because abalone do not breed at regular intervals. Their gametes are also often lost down the drain, as broadcast spawning requires constant, sweeping water flow to work. Even if all goes well and baby abalone are born, no one is sure what levels of light, temperature, and filtration best suit their long-term growth while in captivity.

Outplanting also brings challenges. Scientists do not yet know the best locations to outplant, since the entire California coast is experiencing harsh fluctuations in temperature and food levels due to changing climate. Predators and people, too, often slow the process — like the octopus who has no idea how resource-laden and politically vested its meal is, or the poacher who wants to make a few hundred dollars by selling a recently-outplanted abalone illegally on the black market. Young abalone also hide for a few years when first settled onto reefs, so it can be impossible to gauge outplanting success at the outset, adding an additional challenge for researchers trying to assess outcomes and fine-tune their efforts.

For instance, following an outplanting project conducted in 2015, in which 800 baby green abalone were placed in net-covered PVC pipes to protect them from predators, Barilotti recorded extremely low numbers of survivors for the first year-and-a-half. Then, their numbers appeared to resurge. “Abalone counts went from the low teens to 40, then 70, then up to about 150 animals within a 10 by 10 meter site,” he says, indicating that outplanted abalone may actually thrive given the right conditions and enough time.

‘We don’t know enough yet to say we shouldn’t keep trying.’

Abalone behavior after outplanting poses yet another uncertainty. Because most of the abalone in labs have never seen a wild environment, researchers do not know how they will react to threats like sea stars or other predators once outplanted. Is predator response for these animals, which have no obvious brain structure, innate? Must it be learned? If so, are captive abalone capable of being “taught” typical behaviors like hiding or twisting their shells back and forth until predators are shaken off?

These questions are still being worked out by researchers like Melissa Neuman, Abalone Recovery Coordinator for NOAA Fisheries, who has just begun testing predator responses by placing sea stars atop captive abalone and observing how the snails react.

Despite these challenges, the organizations and people working with abalone are determined not to give up. Jessica Brasher, animal husbandry manager at the Ocean Institute in Southern California’s Dana Point, puts it simply: “We don’t know enough yet to say that we shouldn’t keep trying.” Right now, she explains, “success” does not mean recovery, but rather proving we can figure out the methods necessary to get there.

Consultation and collaboration with Indigenous stakeholders could facilitate this effort. But so far, to the frustration of many coastal tribes, abalone science and data collection in California have largely not involved Native peoples.

The absence of Native voices does not reflect a lack of interest from the tribes. Hillary Renick and Javier Silva of the Sherwood Valley Band of Pomo Indians are immensely concerned about the abalone’s plight in California, and have persistently voiced their need to be heard alongside other groups working on abalone declines. “Discussion should always begin with people indigenous to the land, wherever you are,” Renick asserts. “You’re talking about our habitat and ecology and the cultural significance that goes along with our foods, our plants, our medicines, our homelands, our aboriginal ties to the landscape.”

Silva acknowledges that there is no hard-and-fast answer, no one solution that traditional ecological knowledge — whether from the Pomo people or any other Native tribe — will provide as abalone populations continue to decline. But deliberate and progressive co-management between tribes and other groups involved in abalone recovery would only strengthen restoration efforts.

BODEGA MARINE LABORATORY sits on a foggy, heath-colored headland a mile or so outside the sea-worn village of Bodega Bay, just about an hour-and-a-half drive north of San Francisco. On a damp July afternoon, with droplets of marine layer in my hair and the tang of fresh-caught crab lingering in my nose, I enter the lab to find a small white office where Dr. Laura Rogers-Bennett, research associate for the University of California, Davis and senior environmental scientist for the California Department of Fish and Wildlife, has built her life around abalone. She is perhaps more involved than any individual in efforts to recover the sea snails today.

Biologist Laura Rogers-Bennett, who is raising critically endangered white abalone at the Bodega Marine Laboratory, says “the only thing we can do with this species is captive rearing and putting them out there.” Photo by Dominick Leskiw.

Rogers-Bennett tells me she is raising critically endangered white abalone. The most recent population models estimate that only 3,600 white abalone remain in the wild — just 1 percent of what their population was 20 years ago. With a natural mortality rate of 12 percent each year, the entire species will almost certainly reach quasi-extinction if outplanting is not implemented within the next few years. “The only thing we can do with this species is captive rearing and putting them out there,” she says. Rogers-Bennett is more prepared than anyone to do so — there are over 50 times more white abalone in her lab than there are left in the ocean.

In the meantime, the team at Bodega Marine Laboratory has been outplanting red abalone as a proxy for whites, reestablishing wild red populations where possible, and along the way learning what techniques might be applicable to white abalone outplanting in the future.

Yet, white abalone recovery only makes up about 40 percent of the work Rogers-Bennett and her team do. The rest, she notes enthusiastically, focuses on urchin management, kelp recovery, and restoration possibilities for the other imperiled abalone species of the California coast. Abalone cannot recover just through outplanting if whites or any species of abalone are to make a comeback, we must concurrently work toward restoring the entire coastal kelp forest ecosystem, Rogers-Bennett explains. She, along with Dayton and many others involved in abalone recovery, consider the establishment and enforcement of Marine Protected Areas one of the best ways to do this. There are currently more than 120 Marine Protected Areas covering some 850 square miles of California’s coastal and ocean habitat. Many of these — like the San Diego-Scripps Coastal State Marine Conservation Area and the much larger Richardson Rock State Marine Reserve off San Miguel Island — already provide relatively safe havens and ecological recovery zones for abalone, kelp, and myriad ocean life.

Education also offers an opportunity to change perceptions around abalone, Rogers-Bennett says. Given the moratorium on harvesting, we have the rare chance to adjust how people view these animals, a chance to teach new generations to see abalone less as a commodity and appreciate them as fellow beings, organisms that must be treated with respect and care especially when we choose to interact with them consumptively.

The Ocean Institute in Dana Point, which receives around 100,000 visitors each year, half of which are young students enrolled in marine-related school programs, is doing just that. Students learn and contribute to ocean research through activities such as dissecting squid, identifying animals in tidal pools, and exploring the ocean on a traditional sailing brig to count marine mammals. The institute has now taken steps to incorporate abalone into their programs, too, including the one which grazes slowly around a tank at the entrance, greeting children and adult visitors alike. It often pauses to rest right up against the glass of the tank, photogenically posed on the rim of another, long-passed, abalone’s shell.

THIS PAST AUTUMN, I was given a boxful of abalone shells to use as models for some natural history illustrations I’m working on. One, found many years ago half-buried along a beach in Cambria, a small seaside town on the central California coast, came from a red abalone it’s almost the size of a dinner plate. I pick this shell up in my left hand, the same hand that remembers how it felt to hold, and be held by, a living abalone. Its outer surface is coarse, pocked with four open respiratory holes and ridged by countless, intricate calcium carbonate accretions. Pink and green concentric growth lines, each one matching the color of algae the animal had been eating at the time, ripple across the shell’s surface like rings on a tree trunk. Old tube worm cases, long abandoned, are affixed to it, as are the sun-bleached remains of tiny bryozoans. These aquatic invertebrates are hitchhikers, and serve as reminders that in the vast, mysterious ocean, even a single abalone can become the world to other lifeforms.

Pink and green concentric growth lines matching the color of algae the abalone had been eating at the time ripple across their shells. Photo by Dominick Leskiw.

I flip the shell over to inspect the iridescent interior. Every tilt of my hand reveals a new palette of shimmering hues — violet, brown, blue-green, silver. A hint of orange reminds me of the bright, shiny waders I saw aquaculturists wearing while gathering kelp for their abalone below a dim wooden pier in Monterey. Their sustainable storefront is doing well for now, but rising sea levels may result in its closure in a few years. Dark purple, deep in the shell’s apex, is reminiscent of the urchins, crawling, eating, and clearing the sea floor. “Urchins are not the enemy,” I recall Silva saying during our conversation a few weeks earlier. “They’re changing, and trying to survive, too.” Somewhere between turquoise and olive green, I catch a glimpse of the kelp forest itself, the once-countless fronds which are sparse now, but still swaying and reaching up to the surface.

These colors are real reminders of our ties to a deceased animal, and a potentially dying species. Every long-vacant, ear-shaped abalone shell rings with an opalescent plea, begging us to listen to, and learn from, the plight of these shellfish. Abalone will almost certainly fail to see any significant recovery without human intervention. What ends up happening to these sea snails will reveal our capacity to reinstate and nurture the ecological and cultural complexity of our world that we continue to destroy.

Dr. Benjamin Neal, a marine benthic ecologist at Colby College in Waterville, Maine, served as Leskiw’s advisor at the time of this article’s publication. Leskiw would like to express continuing gratitude for Dr. Neal’s guidance and support throughout the research, travel, and writing processes.


What is a kelp forest?

Kelp forests can be seen along much of the west coast of North America. Kelp are large brown algae that live in cool, relatively shallow waters close to the shore. They grow in dense groupings much like a forest on land. These underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

Kelp forests harbor a greater variety and higher diversity of plants and animals than almost any other ocean community. Many organisms use the thick blades as a safe shelter for their young from predators or even rough storms.

Among the many mammals and birds that use kelp forests for protection or feeding are seals, sea lions, whales, sea otters, gulls, terns, snowy egrets, great blue herons, cormorants, and shore birds.

These dense canopies of algae generally occur in cold, nutrient-rich waters. Because of their dependency upon light for photosynthesis, kelp forests form in shallow open waters and are rarely found deeper than 49-131 feet .

NOAA scientists study kelp forests by visiting the same locations over and over to assess the presence and abundance of a variety of organisms. Monitoring allows marine scientists to determine if the kelp forest is changing over time and to identify the cause of those changes, whether natural or human.


Under the sea: Smashing urchins, restoring kelp forests

Diver and Long Beach resident Ali Krajewski is a volunteer with L.A. Waterkeeper, one of several area organizations working on kelp forest restoration. The Cal State Dominguez Hills master’s student dives with the environmental nonprofit about once a month.

Diver Ali Krajewski in the kelp off Cabrillo Beach. Krajewski is a dive volunteer with L.A. Waterkeeper – one of several area organizations working on kelp forest restoration. She does most of her work 50 yards from shore at Underwater Arch Cove on Palos Verdes Peninsula.

Diver Ali Krajewski in the kelp off Cabrillo Beach. Krajewski is a dive volunteer with L.A. Waterkeeper – one of several area organizations working on kelp forest restoration.

Diver Ali Krajewski in the kelp off Cabrillo Beach. Krajewski is a dive volunteer with L.A. Waterkeeper – one of several area organizations working on kelp forest restoration. She does most of her work 50 yards from shore at Underwater Arch Cove on Palos Verdes Peninsula.

Diver Ali Krajewski with a crab she found in the kelp off Cabrillo Beach. Krajewski is a dive volunteer with L.A. Waterkeeper – one of several area organizations working on kelp forest restoration. She does most of her work 50 yards from shore at Underwater Arch Cove on Palos Verdes Peninsula.

Kelp forest restoration volunteers lay out measuring tape to keep track of their progress.

Purple sea urchins cling to a rock off the coast of Palos Verdes during a kelp forest restoration dive in May.

A perch lingers near purple sea urchins off the coast of Palos Verdes on a kelp forest restoration dive in May.

Diver Ali Krajewski pauses in the kelp off Cabrillo Beach. Krajewski is a dive volunteer with L.A. Waterkeeper, one of several area organizations working on kelp forest restoration. She does most of her work 50 yards from shore at Underwater Arch Cove on Palos Verdes Peninsula.

When you smash a sea urchin, you have to hammer it good and hard to make sure it not only is dead but lyk dood.

That&rsquos one of the tricks of restoring kelp forest, according to Ali Krajewski, a dive volunteer with L.A. Waterkeeper, which is one of several area organizations working on kelp forest restoration.

Volunteer divers like Krajewski spend an hour at a time beneath the waves killing sea urchins where the small creatures have taken over and made barren the ocean floor.

With the urchins gone, the kelp forests &ndash an essential habitat for hundreds of ocean critters decimated over the last century &ndash can regrow.

On a recent day, Krajewski, two other volunteers and a staffer from L.A. Waterkeeper prepare to dive, shimmying into wetsuits and mapping out where on the ocean floor each person will work as their boat rocks in the swell 50 yards from shore at Underwater Arch Cove on the Palos Verdes Peninsula.

This is the main site of Southern California restoration these days. From 2001 to 2008, a separate restoration project sponsored by the Coast Keeper Alliance did restoration work from Ventura County to San Diego County using a different technique. In Orange County, kelp forests have rebounded, though work still needs to be done.

The reason you have to thoroughly dismember the urchins, Krajewski says, is so other divers behind you don&rsquot try to kill an urchin you&rsquove already exterminated. Another tip: if you&rsquore hammering at sea urchins on a rock or in a crevasse, you need to take out the ones at the bottom before the ones at the top, so that debris from the upper urchins doesn&rsquot float down and obscure the still-living urchins at the bottom.

Goggles on, Krajewski hunkers onto the gunwale of the boat, splashes backward into the water, and sinks through the murky depths on her way to continue the systematic slaughter of the urchins.

At first she felt a little guilty taking the lives of so many urchins. But no more.

The urchins &ndash runty, small and underdeveloped by urchin standards &ndash have taken over areas off the Palos Verdes coast that once thrived with kelp forests. Upward of 70 urchins per square meter dominate in these barrens, eating young kelp before it has a chance to establish itself. In the past 100 years, 75 percent of the kelp forests off Palos Verdes have disappeared.

Without the kelp forests, other marine creatures have nowhere to go, nowhere to live.

&ldquoI have to explain how emaciated the sea urchins are inside, and it&rsquos not a good life for them. The ones that survive are more healthy,&rdquo says Krajewski, who estimates she&rsquos been on 50 dives with L.A. Waterkeeper.

And the runty urchins can&rsquot be harvested for uni, a popular sushi made from urchin gonads. It&rsquos not worth it with the urchins so small.

The Long Beach resident and Cal State Dominguez Hills master&rsquos student dives with L.A. Waterkeeper about once a month and has a ritual worked out: wake up at 5 a.m., mix a breakfast smoothie, brew some coffee for later, heat some soup to put in a thermos &ndash hot soup after a cold dive feels good &ndash hit the road.

Krajewski describes the decimation of the kelp forests off Palos Verdes as the perfect storm. Sea otters, which are urchin predators, had been hunted to near extinction in Southern California, though some remained farther north. Other urchin predators like California spiny lobster and California sheephead were also decimated by fishing. When human development on the peninsula started, it washed sediment, pollution and chemicals into the water, killing kelp.

With the kelp forests dying, the urchins moved in. But they overpopulated.

The restoration work under the water is monotonous, and there is no conversation, no music, no noise. That&rsquos exactly how Krajewski likes it.

&ldquoOnce every five or 10 minutes, I have to stop and appreciate it. I&rsquom in a gorgeous environment,&rdquo says Krajewski, 33.

Krajewski, who was raised in Los Angeles, spent a couple of years at Glendale Community College before transferring to Cal State Long Beach to finish her degree in marine biology. She works part time at Cabrillo Marine Aquarium in San Pedro, but pays the bills with a job at Trader Joe&rsquos.

From above, barely anything is visible below the waves, where the volunteers first measure out transect lines &ndash 2 meters apart, lines within which to work. Every couple of minutes a column of air bubbles burbles up, or a bright yellow air tank gleams.

Krajewski initially had to overcome fears of dangerous creatures in the opaque water.

&ldquoJust going in there, you can&rsquot see through the water, stuff is brushing up against your legs, it&rsquos a little freaky. So learning exactly what is down there, and understanding it and getting to the point where I know what&rsquos down there, there isn&rsquot much to be afraid of,&rdquo she says.

After a second dive, Krajewski brings up several urchins. She demonstrates how to smash them against the gunwale of the boat, saying you can pierce the shells with the pick end of the hammer or smash them with the blunt end. The urchins break like thick, hollow egg shells, and urchin guts spread across the gunwale.

For fish that live near the urchin barrens, hammer time is a buffet of freshly prepared uni. The fish flit near the divers even before the smashing begins, waiting to feast on edible urchin parts.

&ldquoThey figured it out by about the second week after we started,&rdquo Krajewski says. &ldquoI have to be pretty careful when I&rsquom hammering. Fish will dart in and I will have to try not to hit it with the hammer. They&rsquore pretty brazen.&rdquo

After two dives, the volunteers pull anchor and start back to Marina del Rey. A day that started chilly and cool has warmed up, with sunshine streaming down. The boat tears through the waves.

When Krajewski returns, the kelp may already be growing back. The algae is one of the quickest growing species in the world, rising as much as 2 feet per day. With the kelp will come the fish and other ocean critters that call the forests home.

&ldquoIt confirms for me that I&rsquom doing the right thing in conservation work. Even just a couple weeks later, going to the same spot and noticing all the life that was hidden before, that couldn&rsquot have crawled around before because of the spiky sea urchins. There&rsquos more color, biodiversity,&rdquo she says.

&ldquoYou&rsquore taking it back to what it should be, and it&rsquos the most beautiful thing.&rdquo


Purple reign

The research vessel Xenarcha is about 10 minutes out of the Port of Los Angeles on an overcast March morning. A gray whale breaches off the boat’s bow, its tail sending a spray of seawater skyward. The 28-foot boat belongs to the Bay Foundation, which has restored nearly 53 acres of Palos Verdes Peninsula’s kelp forests since 2013.

That’s a fraction of the 2,500 acres of seaweed estimated to exist a century ago. But it’s a huge increase since the late 1960s, when kelp had become all but extinct in that area.

Rough water gives way to the glassy calm of Honeymoon Cove and its eight acres of giant kelp, roots anchored to rocky reefs some 18 to 30 feet below.

For decades, this cove was largely devoid of life, devastated by seaweed-eating purple urchins. The urchins resemble small, spikey balls and are a natural part of kelp ecosystems. But when the predators that keep their numbers in check disappear, the population booms and can quickly consume a kelp forest, creating what is called an urchin barren. Once their food is gone, the urchins, which can live for more than 50 years, lower their metabolism and essentially hibernate.

Over the past half century, overfishing and pollution killed off sheepshead fish, abalone, and other marine animals along the Los Angeles Coast that either preyed on purple urchins or competed with them for habitat. Commercially valuable species like the red urchin also vanished once their only food source, kelp, was lost. And most purple urchins aren’t marketable because their only edible parts, their gonads, are considered too small.

Before kelp restoration began in 2013, Honeymoon Cove was “a complete barren, with densities of urchins approaching 70 per square meter,” says Ford.

The Bay Foundation now hires out-of-work red urchin divers to methodically cull the purples by smashing them with hammers.


Materiale en Metodes

Data Compilation and Field Sampling

A comprehensive field sampling was performed in 2012 to gather data on Norwegian L. hyperborea forest characteristics along gradients of latitude, wave exposure and depth. Due to logistical reasons when aiming to cover huge areas along Norway’s 100 000 km coastline, as well as challenges of conducting safe diving in the most wave exposed areas, the 2012-study lack data from the most remote and wave exposed areas. These data were therefore supplemented with existing data collated from a range of studies, published in scientific articles and technical reports, where also sampling methods were thoroughly described (Rinde et al., 1992 Rinde and Christie, 1992 Skadsheim et al., 1993 Christie et al., 1994, 1995 Skadsheim and Rinde, 1995 Bekkby et al., 2014b) from 1991 to 2008. The final dataset consisted of 630 observations from 74 field stations (Figure 1). This provided data of L. hyperborea canopy density and individuals measured for age, length (stipe and lamina), weight (holdfast, stipe and lamina) and stipe-associated epiphytic algal biomass (all drip-dried fresh weights). The data from 2012, accounting for 51% of the total dataset, were sampled with a systematic design to cover gradients in depth, wave exposure and latitude. Five out of the six Norwegian ecoregions were covered (Figure 1). Another 44% of the dataset came from Bekkby et al. (2014b), which also followed a systematic sampling scheme along a wave exposure and ocean current gradient, although restricted to one depth (5 m) and one ecoregion only (Table A, Supplementary Material). All data were collected using scuba diving at pre-selected stations, based on maps and models of bathymetry and wave exposure covering the suitable habitat of L. hyperborea in the NE Atlantic. For kelp canopy density measurements, the number of canopy plants (easily recognized from the medium and lower understory layers by their length) per m 2 was recorded for usually 10 (but see below) replicate 50 × 50 cm frames, randomly dropped along transects at 5, 10, and 15-20 m depths (15 m was chosen when kelp was not found at 20 m) recorded from the dive computer (see Table 1 for number of replicates within each ecoregion and depth interval). Measurements of relative depth were adjusted according to the time- and site-specific deviation from low tide, which in Norway is a maximum of 2.5 m in the north (Barents Sea) and less than 0.5 m in the south (Skagerrak). One representative canopy plant was randomly collected within each of three of the frames at each depth interval. The plants were brought to the surface for measurements of length (lamina and stipe), drip-dry fresh weight (lamina, stipe, holdfast, and stipe-associated epiphytic algae), and age (growth rings at stipe base, following the procedures of Kain, 1963). The compiled data from 1991 to 2008 had been sampled with five or more replicates at each station (Rinde et al., 1992 Skadsheim et al., 1993 Christie et al., 1994, 1995 Skadsheim and Rinde, 1995 Bekkby et al., 2009). The total dataset covered a spatial gradient from 58.2 to 70.7°N and from 5.4 to 30.1଎ (Figure 1). Some of the northernmost parts of the coastline were heavily grazed by green sea urchins, Strongylocentrotus droebachiensis (Rinde et al., 2014), thus no sampling could be performed there. Also, the most exposed coastlines were too rough for secure diving and therefore not sampled.

Figuur 1. Location of the 74 stations (red dots) visited in this study and the six Norwegian coastal ecoregions. For more information on sample sizes, see Table 1.


Kyk die video: Kelp drying (September 2022).