Ant Atoll, 9 miles southwest from Pohnpei and now Micronesia’s 2nd official UNESCO Biosphere Reserve due to the efforts of the CPS (Conservation Society of Pohnpei).

We wait patiently as the boys get their nutriment for the day ahead. Ant Atoll is our destination and the suspense is rising. The ocean is mirror calm, the weather benign — perfect for our 1.5 hour journey across the water. Our initial sojourn to the south side two days ago equated such conditions and the reef did not disappoint: pure joy! Therefore, we anticipate more of the same.

Greeted by a curious white tip reef shark (Triaenodon obesus) before descent into the twilight depths on the western side of Ant Atoll. Photo: Sonia J. Rowley.

Greeted by a curious white tip reef shark (Triaenodon obesus) before we descend the sheer wall into the twilight depths on the western side of Ant Atoll. Photo: Sonia J. Rowley.

Ant Atoll is, in fact, a considerable size, being half the size of Pohnpei (129 square miles/334.1 square km), yet with a human population of 10 — how peaceful! Today we target the west side, with a supermoon rendering the corals of the reef flat exposed. From the reef crest a shear wall descends to more than 300 m (1000 ft) in depth, a small ledge is located and we anchor in. I drop in first and whilst awaiting the boys, am met by a curious and somewhat territorial White-tip reef shark.

Brian D. Greene having captured Chromis circumaurea (Pyle et al. 2008) from 120 m (394 ft) on the western side of Ant Atoll. Photo: Sonia J. Rowley.

Brian D. Greene having captured Chromis circumaurea (Pyle et al. 2008) from 122 m (400 ft) on the western side of Ant Atoll. Photo: Sonia J. Rowley.

On descent the thermocline is unusually mild as we hit ~122 m (400 ft); now it’s time to get busy. Brian is to the right capturing an old friend: Chromis circumaurea Pyle et al. 2008, described previously by himself, Richard Pyle and John Earle.

Chaos of gorgonians at 120 m (394 ft) on the western side of Ant Atoll. Such an abundance and diversity of gorgonian corals are typical of twilight reefs. Photo: Sonia J. Rowley.

Chaos of gorgonians at 120 m (394 ft) on the western side of Ant Atoll. Such an abundance and diversity of gorgonian corals are typical of twilight reefs. Photo: Sonia J. Rowley.

I’m surrounded by gorgonians sufficiently so that it’s overwhelming, perched on an overhang I collect in earnest, there’s not a moment to waste. Acanthogorgia, Paracis, Keroeides, Heliania, Annella, Astrogorgia…. hmmm finding those a little deep, interesting, yes Parisis – now I know we’re past the temperature gradient, this one’s fantastic and most definitely new. Brian glides past now to my left; “how’s it going Sonia?” “Awesome!” I reply in the typical ‘Smurf’ through-Trimix dialect; you can’t help but giggle when you sound like an animation – it never gets old.

New species aren't always glamorous! Taken at 122 & 115 m (400 & 377 ft) respectively. Note the sediment and algae present. Photo: Sonia J. Rowley.

New species aren’t always glamorous! Taken on the western side of the atoll at 122 & 115 m (400 & 377 ft) respectively. Note the sediment and algae present. Photo: Sonia J. Rowley.

BOOM! This one is a new genus…. more comparative investigation awaits! At Bishop Museum we have an excellent library of taxonomic literature, which is a peaceable past time to dissolve into: numerous different languages and subjective taxonomic opinions renders an interesting experience that crowns the delight of collecting the colonies in the first place.

A delicate Acanthogorgia colony at 90 m (295 ft) depth on the western side of Ant Atoll. Photo: Sonia J. Rowley.

A delicate Acanthogorgia colony at 90 m (295 ft) depth on the western side of Ant Atoll. Photo: Sonia J. Rowley.

The rush of being at depth and doing the work masks any awareness of the cold, which is typically less than 17°C/62 F. On ascent passing into warmer clines is always a welcome surprise, but not, however, for my catch! Gorgonians are particularly sensitive to temperature even moreso than pressure — numerous species oxidise (begin to turn black) at elevated temperatures when bought up from the deep ocean (e.g., > 500 m) and this is also true for colonies at twilight depths.

The water clarity on the western side of Ant Atoll from ~ 40 m (130 ft). The ocean is a majestic sapphire blue that captures the soul and stills the mind. Photo: Sonia J. Rowley.

The water clarity on the western side of Ant Atoll from ~ 40 m (130 ft). The ocean is a majestic sapphire blue that captures the soul and stills the mind. Photo: Sonia J. Rowley.

Here, on the western side of the atoll, there appears two distinct differences to that of the southern side; firstly there is only a mild temperature gradient, whereas two thermoclines exist towards the twilight zone on the southern side. Secondly the topography involves a shear wall with enticing caves on the western side compared to a gradual incline on the south side. Both yield different results in terms of the biodiversity present, confirming the influence of the environment on the reef and thus inherently intriguing to us all. The water clarity however, is astounding at both sites > 50 m (164 ft) for sure.

Twilight reefs at Ant Atoll. The left is the south side with a sloping sandy-rocky substratum; the right is the west side with a shear wall with ledges as you descend beyond 100 m (330 ft). Photo: Sonia J. Rowley.

Twilight reefs at Ant Atoll. The left is the south side with a sloping sandy-rocky substratum (with Richard Pyle); the right is the west side with a shear wall with ledges as you descend beyond 100 m (330 ft). Photo: Sonia J. Rowley.

To me diving takes me to a place that is without definition, and for fear of sounding corny or shooting for a plug, I can honestly say that using the Poseidon SE7EN is like a second skin! Feeling so free and nimble under the water is ideal for what we do. Everything runs like clockwork, yet to understand the true algorithms behind this technology is no easy feat. The bottom line is that there are more built-in safety tests in this electronically-controlled rebreather to ensure the optimal diving experience and comfort than anything before.

Greeted by our friend from the beginning of the dive; Triaenodon obesus whilst I investigate gorgonians in a shallow cave during decompression. Photo: Sonia J. Rowley.

Greeted by our friend from the beginning of the dive; Triaenodon obesus whilst I investigate gorgonians in a shallow cave during decompression. Photo: Sonia J. Rowley.

Greeted by my friend from the start, will he be there tomorrow?