On the surface, Monterey Bay has a few things in common with the coasts of Peru and Chile: marine researchers, military bases, poetic summer fog, chilly beaches. Dolphins draw boatloads of life-jacketed tourists, and fishermen haul prolific catches onto bustling wharfs.

But the unfathomable ocean only begins at its surface. What life flourishes under that endless gray plane? How do ecosystems compare along the productive cold currents of the eastern Pacific coast?

I aim to find out by scuba diving in the three countries.

The first stop is a late summer dip off Lovers Point in Pacific Grove. It’s supposed to be the warmest time of year, when upwelling subsides and the sun has a chance to heat up the surface of Monterey Bay. But the chill of the water makes me gasp, even through 5 millimeters of neoprene.

I sink below the surface with divemaster Lonny Lundsten – who is also, conveniently, an MBARI video analyst and deep-sea marine biologist. Fishing is allowed in this area, Lundsten explains, so it’s not as biodiverse as the underworld at protected Point Lobos. But it looks rich to me.

The sea floor at 34 feet sways with life, a forest dominated by macrocystis kelp anchored to rocks in the sand. We see krill, limpets, crabs and snails beneath waving fronds of various seaweeds: feather boa kelp, bubble kelp, Turkish towel. Perch, rockfish and slender lovelies called señoritas hide behind sprouts of grasses. Tiny shards of white plastic impersonate shells.

We also see some of the animals that could be most vulnerable to acidification: coralline-encrusting algae and orange cup corals. As the ocean’s pH declines, they’ll have a harder time building their calcified armor.

Almost three weeks later I’m suited up like a space-seal in Pucusana, Peru, flippering through the green with divemaster Luis Rodriguez. Dense clusters of white anemones cling to rock walls in the green water. Groups of Peruvian morwong, small rusty fish with white zebra stripes, dart between the kelp. I swim over several purple sea suns. Chitons, urchins, anemones and snails with algae-encrusted shells nestle under swaying kelp fronds. Rodriguez points out an unblinking little ray called a guitarfish sprawled clandestinely on the sea floor.

After analyzing Rodriguez’s video and my still shots of the dive, Lundsten determines that most of the Peruvian species I’ve seen are different from the Monterey varieties. The ecosystem appears less diverse, he says, possibly because of the sandstone substrate or overfishing.

Rodriguez thinks it’s the latter. He laments the carelessness of the Pucusana fishermen, who, he says, will keep any and all fish they catch. That’s why the fish we’ve seen are so small, he says.

He also blames the contractors who dump waste into the sea. We’d seen the evidence during our dive: cement settled into the sand, algae wrapped around rusty rebar.

A week later, in Herradura Bay off the coast of Coquimbo, Chile with scuba instructor Helmo Perez Ortiz, we’re suited up in wetsuits, fins and masks, but we don’t use tanks or regulators, instead holding our breath to dive 12 feet to the bay floor.

The water is a cool 55 degrees Fahrenheit at the beginning of upwelling season. We see six kinds of kelp, shape-shifting in shades of red, green and brown. I recognize anemones, sea stars and sea suns. Ortiz identifies various small furtive fish as blanquillo (tilefish), pez agujilla (needle fish) and bilagay (morwong). The find of the day is a rough gray abalone – in Spanish dubbed loco, despite its calm temperament.

Afterward, Ortiz and I chat. “Mi etorno fue el mar,” he says. He was born on the coast and grows old on the coast – his life has always been the sea. But he’s worried about the changes he’s seen.

Now there are fewer of every kind of fish – especially big, edible ones – than when he first learned to dive. Additionally, Ortiz sees more jellyfish. As global warming rearranges marine ecosystems, the pulsing zooplankton appear adaptable to changes other species can’t stomach.

And another thing. Ortiz grabs a white plastic grocery bag off his desk and shakes it; outside his office window, an identical bag bobs in the bay. “These bags from stores are everywhere,” he says.

The equator may separate different species of fish, but that bag is universal. The garbage, the overfishing, the shifty climate changes that outpace scientific understanding – this is the language of the sea that needs no translation.

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VIDEO -- Kera in Pucusana, Lima, Peru

<a href="http://video.msn.com/video.aspx?vid=9a49eba4-eb06-4db5-bd23-53f8b29c5992" target="_new" title="KERA EN PUCUSANA LIMA PERU ">Video: KERA EN PUCUSANA LIMA PERU </a>