Ecosystems

The black lava sand is one of the characteristics of Bali. It makes the colour of these nudibranchs stand out too.

Why are the Balinese waters so rich?

It all starts east of the Philippines where the constant blowing of the tradewinds and the ocean currents forces huge masses of water up against the Philippines, where it is trapped and forced southwards. 

Most of this current is directed by ocean bottom morphology to flow into the Sulawesi basin and down between Borneo and Sulawesi—the fat red arrow on the figure above. The only thing sitting in this giant current’s way is the lesser Sunda Islands, predominantly Bali, Lombok, Sumbawa, Flores and Timor—with Bali sitting right in the ideal position to benefit from this flow.

Previous studies of shipwrecks in the United Kingdom and the Red Sea have shown that such artificial reefs often create new and different types of habitat than natural reefs.

Fish thrive on WWII shipwrecks

In 2016, the National Oceanic and Atmospheric Administration (NOAA) undertook a closer examination of the wrecks of the German U-boat U-576 and the Nicaraguan freighter SS Bluefields, using glass-domed submersibles. The two historically significant and deep (200m) shipwrecks sank near one another on the continental shelf of North Carolina, USA, during World War II.

Giant kelp (Macrocystis pyrifera) is a species of kelp (large brown algae)

Kelp forests help the climate

Kelp is an ecologically and economically important foundation species in California, where forests line nutrient-rich, rocky bottom coasts. It also might alleviate acidification caused by too much atmospheric carbon being absorbed by the seas.

A new interdisciplinary analysis of giant kelp in Monterey Bay off the coast of California shows that near the ocean’s surface, the water was less acidic, suggesting the kelp canopy does reduce acidity.

Coral larvae being collected at Palmyra Atoll National Wildlife Refuge. This allows researchers to enumerate the number of baby corals settling on a reef.

Corals seek cooler pastures in subtropical waters

Coral reefs have been seeking new pastures, as rising temperatures heat up their natural habitats.

Over the last four decades, coral reefs have been progressively shifting their homes from equatorial waters to more temperate regions.

The reason? Climate change.

“Climate change seems to be redistributing coral reefs, the same way it is shifting many other marine species,” said Nichole Price, a senior research scientist at Bigelow Laboratory for Ocean Sciences and lead author of the paper on the topic.

Offshore coral reefs are healthier

Researchers from the Woods Hole Oceanographic Institution (WHOI) and the Centro de Investigaciones Marinas—Universidad de La Habana (CIM-UH) have discovered that offshore coral reefs that are also protected tend to be healthier than nearshore ones.

In the study, seawater from 25 reefs in Cuba and the Florida Keys in the US were tested for nutrients and other parameters that would give researchers a glimpse into the microbial community present.

Using sounds of healthy reefs to attract young fish

Healthy coral reefs are full of sounds of life—with the whistles, pops and grunts of fish, the crackle of snapping shrimp, etc. These sounds travel out through the ocean currents, and “advertise” to young fish to come and settle down at this particular reef ecosystem.

However, when reefs are degraded or dying, the environment falls silent. Literally.

As a result, young fish do not find their way to such reefs, and this exasperates the reef's dire situation.

River Treasures: Freshwater Biodiversity in Italy

The trench live in freshwater lakes and streams. Photo by Marco Colombo.

When considering underwater photography, we usually think about images of wonderful coral reefs, colourful fish, clear waters and undersea landscapes. In fact, 70 percent of our planet is covered by water on its surface, and, even though 97 percent of this is saltwater, the remaining three percent is freshwater in rivers, streams, lakes, ponds, marshes and groundwater.