{"id":79427,"date":"2022-02-16T02:47:00","date_gmt":"2022-02-16T01:47:00","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=79427"},"modified":"2022-02-15T13:47:45","modified_gmt":"2022-02-15T12:47:45","slug":"seagrasses-continue-to-release-methane-after-their-die-off","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/seagrasses-continue-to-release-methane-after-their-die-off\/","title":{"rendered":"Seagrasses con\u00adtinue to re\u00adlease meth\u00adane after their die-off"},"content":{"rendered":"\n

Meth\u00adane is formed and re\u00adleased from seagrass mead\u00adows, even dec\u00adades after the plants died off.<\/p>\n\n\n\n

Seagrass meadows play an important role in the marine carbon cycle and our climate. On the one hand, they sequester carbon dioxide from the atmosphere and store it underground, on the other hand, they emit the potent greenhouse gas methane. Researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, have now investigated what controls methane production and release from seagrass meadows. They now present their results in the journal Proceedings of the National Academy of Sciences (PNAS).<\/p>\n\n\n\n

Seagrasses cover shal\u00adlow coastal re\u00adgions of tem\u00adper\u00adate and trop\u00adical seas world\u00adwide. Seagrass mead\u00adows form the basis of an es\u00adsen\u00adtial eco\u00adsys\u00adtem that is home to nu\u00admer\u00adous an\u00adim\u00adals, in\u00adclud\u00ading en\u00addangered spe\u00adcies of sea turtles, seahorses, and fishes. They also pro\u00adtect the coasts from erosion and se\u00adquester mil\u00adlions of tons of car\u00adbon di\u00adox\u00adide from the at\u00admo\u00adsphere every year. But seagrass mead\u00adows also emit green\u00adhouse gases, es\u00adpe\u00adcially meth\u00adane, which has a much stronger ef\u00adfect on our cli\u00admate than car\u00adbon di\u00adox\u00adide.<\/p>\n\n\n\n

Where does the meth\u00adane come from?<\/h5>\n\n\n\n

Sina Schorn and her col\u00adleagues from the Max Planck In\u00adsti\u00adtute for Mar\u00adine Mi\u00adcro\u00adbi\u00ado\u00adlogy and Hy\u00addra Mar\u00adine Sci\u00adences first in\u00advest\u00adig\u00adated what the meth\u00adane in the seagrass mead\u00adows is formed from. Seagrasses, like many ter\u00adrestrial plants, form large peat de\u00adpos\u00adits un\u00adder the sed\u00adi\u00adment sur\u00adface. Ter\u00adrestrial peats are known to re\u00adlease large amounts of meth\u00adane from the de\u00adcom\u00adpos\u00adi\u00adtion of the or\u00adganic ma\u00adter\u00adial. Thus, the re\u00adsearch\u00aders ex\u00adpec\u00adted that the mech\u00adan\u00adisms be\u00adhind meth\u00adane pro\u00adduc\u00adtion are sim\u00adilar in seagrass mead\u00adows. However: The op\u00adpos\u00adite was the case.  \u201cHere we ex\u00adper\u00adi\u00adenced our first sur\u00adprise,\u201d ex\u00adplains Schorn, the lead au\u00adthor of the study.<\/p>\n\n\n\n

\u201cIn seagrass sed\u00adi\u00adments, meth\u00adane is formed solely from one class of or\u00adganic com\u00adpounds,\u201d Schorn says. \u201cThese so-called methyl\u00adated com\u00adpounds are pro\u00adduced by the seagrass plant it\u00adself. Spe\u00adcial\u00adized mi\u00adcroor\u00adgan\u00adisms, the meth\u00adano\u00adgenic ar\u00adchaea, then con\u00advert these com\u00adpounds into meth\u00adane.\u201d The com\u00adpounds in\u00adclude, amongst oth\u00aders, be\u00adtaine: a com\u00adpound that helps seagrasses cope with changes in sea\u00adwa\u00adter sa\u00adlin\u00adity. As meth\u00adano\u00adgenic ar\u00adchaea can use these com\u00adpounds dir\u00adectly, meth\u00adane pro\u00adduc\u00adtion in seagrass mead\u00adows is highly ef\u00adfi\u00adcient and ro\u00adbust against en\u00advir\u00adon\u00admental stresses.<\/p>\n\n\n\n

And something else is dif\u00adfer\u00adent in seagrass mead\u00adows than on land: The re\u00adlease of meth\u00adane into the wa\u00adter column is very fast. First of all, the plant tis\u00adsue acts as a straw, help\u00ading the gas to es\u00adcape from the seabed into the wa\u00adter. Be\u00adcause seagrasses only grow in shal\u00adlow wa\u00adter, pela\u00adgic mi\u00adcroor\u00adgan\u00adisms have little op\u00adpor\u00adtun\u00adity to con\u00adsume the meth\u00adane be\u00adfore it ends up in the at\u00admo\u00adsphere. Ad\u00addi\u00adtion\u00adally, the sea\u00adwa\u00adter flow\u00ading through the sands on which these seagrasses grow, quickly \u2018washes out\u2019 meth\u00adane from the sed\u00adi\u00adment.<\/p>\n\n\n\n

Also dead seagrass mead\u00adows are sources of meth\u00adane<\/h5>\n\n\n\n

As part of their study, the Bre\u00admen re\u00adsearch\u00aders sampled a dead seagrass meadow. \u201cHere we en\u00adcountered an\u00adother sur\u00adprise,\u201d re\u00adports Jana Milucka, senior au\u00adthor of the study and head of the Green\u00adhouse Gases Re\u00adsearch Group at the Max Planck In\u00adsti\u00adtute for Mar\u00adine Mi\u00adcro\u00adbi\u00ado\u00adlogy. \u201cThe rates of meth\u00adane pro\u00adduc\u00adtion were sim\u00adilar to those in the in\u00adtact seagrass meadow.\u201d Ob\u00advi\u00adously, meth\u00adane is still formed in dead seagrass sed\u00adi\u00adments. \u201cWe be\u00adlieve that the reason be\u00adhind this con\u00adtinu\u00ading meth\u00adane pro\u00adduc\u00adtion is that methyl\u00adated com\u00adpounds per\u00adsist in the plant tis\u00adsue for a very long time,\u201d Milucka says. They could even be de\u00adtec\u00adted in plant tis\u00adsue that had died more than two dec\u00adades ago.<\/p>\n\n\n\n

Meth\u00adane emis\u00adsions par\u00adtially off\u00adset the blue car\u00adbon ef\u00adfect<\/h5>\n\n\n\n

\u201cCur\u00adrently, we are see\u00ading a die-off of seagrass mead\u00adows world\u00adwide which has a dev\u00adast\u00adat\u00ading ef\u00adfect on the coastal eco\u00adsys\u00adtems. Our res\u00adults cau\u00adtion that whereas upon the death of the plant car\u00adbon di\u00adox\u00adide from the at\u00admo\u00adsphere will no longer be se\u00adquestered and stored in the sed\u00adi\u00adment as ‘blue car\u00adbon’, meth\u00adane may still con\u00adtinue to be re\u00adleased\u201d, Milucka ex\u00adplains.<\/p>\n\n\n\n

The work re\u00adin\u00adforces the im\u00adport\u00adance of seagrass mead\u00adows for our cli\u00admate and high\u00adlights the need to bet\u00adter un\u00adder\u00adstand and con\u00adserve these eco\u00adsys\u00adtems. Seagrass mead\u00adows are nearshore hab\u00adit\u00adats, and coastal re\u00adgions are most dra\u00admat\u00adic\u00adally af\u00adfected by an\u00adthro\u00adpo\u00adgenic changes. \u201cWe need to un\u00adder\u00adstand how the seagrass meadow eco\u00adsys\u00adtem func\u00adtions in or\u00adder to de\u00adterm\u00adine the im\u00adpact of the on\u00adgo\u00ading global change on it,\u201d Schorn em\u00adphas\u00adizes.<\/p>\n\n\n\n

Next, the re\u00adsearch\u00aders at the Max Planck In\u00adsti\u00adtute for Mar\u00adine Mi\u00adcro\u00adbi\u00ado\u00adlogy plan to ex\u00adtend their meas\u00adure\u00adments to other re\u00adgions and other seagrass spe\u00adcies. They also plan to study the mi\u00adcroor\u00adgan\u00adisms in\u00advolved in meth\u00adane pro\u00adduc\u00adtion in greater de\u00adtail, as they are sur\u00adpris\u00adingly di\u00adverse and largely un\u00adder\u00adstud\u00adied.<\/p>\n\n\n\n