Ar wyliau Nadolig swnllyd yn Awstralia, roedd yr haul yn treiddio drwy'r awyr las uwchben Rhwyf Mawr y Bae.

During a noisy Christmas vacation in Australia, the sun pierced through the blue sky above Rhwyf Mawr y Bae.

Roedd lliwiau bywiog y cyrff coralgwyn yn creu symffoni o liwiau o dan y dŵr.

The vibrant colors of the coral bodies created a symphony of colors underwater.

Ar y dŵr, roedd clychau cerdd ddrwg yn y clywedu, yn atseinio wrth i bobl fwynhau hwyl yr ŵyl o'u cychod i gerddorfa poblogaidd.

On the water, bells of bad music were heard, echoing as people enjoyed the festive fun from their boats to a popular orchestra.

Ger caribiad y venue hwn, roedd Geraint, biolegydd morol o Gymru, yn ychwanegu't tro.

Near this venue's harbor, Geraint, a marine biologist from Wales, was adding his touch.

Roedd rhyfeddod yng ngolwg ei lygaid glas wrth iddo sganio'r cilfachau cyfoethog.

There was wonder in his blue eyes as he scanned the rich coves.

Roedd yn pasiedig, ond nid trafferth.

He was experienced, but not troubled.

Y defrysi yn ogystal â pheryglon y bywyd o dan y môr oedd agos i'w galon.

The fascination as well as the dangers of life under the sea were close to his heart.

Roedd y pwysau o gwblhau ei ymchwil cyn y Nadolig yn pwyso ar ei ysgwyddau.

The pressure to complete his research before Christmas was weighing on his shoulders.

Tra oedd Geraint yn golofni dan yr eigion glas, roedd ei ben yn sydyn yn byw.

While Geraint was focused under the blue ocean, his mind suddenly sharpened.

Gwyliodd Rhiannon, ffrind a cilydd ymchwilydd, fel y pydai'n taro ei hunan ag endid merch ogof ddiethr.

Rhiannon, a friend and fellow researcher, watched as she drifted closer to a peculiar underwater cavern.

Profodd Geraint yr hydydoleg mewn corff piwllog a gwellach.

Geraint experienced the hydrography in a shimmering, inviting pool.

Gynifer llithriog o chwiliaid yn gyflawn, ond llawer hefyd yn dendrocii.

Several slippery creatures were complete, but many were also elusive.

Aeth ei corff yn gyflym i redeg walch yn erbyn hyrddiat.

His body quickly moved to outrun a surge.

"Na, rhaid i mi fynd ymlaen," meddai Geraint wrth ei hunan yn benderfynol.

"No, I must go on," Geraint said to himself determinedly.

Er gwaethaf ei boen, cafodd y data angenrheidiol, mae'n gwybod byddai'n gallu cyflawni ei benderfyniadau ymchwil.

Despite his discomfort, he obtained the necessary data, knowing he would be able to fulfill his research goals.

Pan ddaeth i'r arwyneb, roedd ei wyneb yn wyn fel cynnig pethau newydd, a safodd Rhiannon wrth ei ochr.

When he surfaced, his face was as pale as starting new tasks, and Rhiannon stood by his side.

"Ti'n iawn, Geraint?

"Are you alright, Geraint?"

" gofynnodd hi'n ofalus, yn nodi bod rhaid iddynt weithredu'n gyflym.

she asked carefully, noting that they needed to act quickly.

Gyda'i chefnogaeth, cydweithiodd y pâr yn galed, y wybodaeth yn cael ei gweld dan olau newydd fyddai'n lleihaur cânt.

With her support, the pair worked hard, the information being seen in a new light that would reduce their concerns.

Penderfynodd Geraint wneud defnydd gorau o'r data.

Geraint decided to make the best use of the data.

Cyhoeddodd eu canfyddiadau ar frys, yn rhannu'r neges brys ar wyryf coralgwyn.

He published their findings quickly, sharing the urgent message about the pristine coral.

Yn ei cwmdir gwerthfawrogodd fyd nad ydy ef bellach yn ei gyfrif ei ucht ei fynd sef.

In his surroundings, he appreciated a world he no longer took for granted.

Er bod y profiad yn unig i'w fynd, tanlinellodd pob rhinweddoldeb bywyd, ymrwymodd Geraint i gydbwyso ei angerdd er y gad y môr a'i iechyd ei hun, gan adnewyddu'r adduned i ddim amheuir.

Though the experience was solely his, it underscored every virtue of life, and Geraint committed to balancing his passion for the sea with his own well-being, renewing the promise to leave no doubt.

Ar ol eu llwyddiant, eisteddodd Geraint a Rhiannon ar lan y môr, y golygw teryou o garolau a'r nos yn gorso i mewn.

After their success, Geraint and Rhiannon sat by the seashore, with the vibrant sights of carols and the evening closing in.

Roedd Nadolig yn dod, ac roedd y wlad hefyd yn ei bwysleisio.

Christmas was approaching, and the country was also feeling its significance.