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.

Help protect the Coral Reefs

Our coral reefs are now under threat not only from the global warming, pollution and exploitation but also by the conduct of divers in these sensitive areas. The reefs are now calling for our protection both when we dive and as contributors to the ongoing struggle to preserve these unique ecosystems for future generations.

The coral sanctuary is a wildlife hotspot, teeming with spinner dolphins (shown in this archive photo) and boasting rare species, including prehistoric fish and dugongs.

Flourishing coral sanctuary discovered off East Africa

The coral sanctuary is a wildlife hotspot where species are thriving despite warming events that have killed their neighbours

The coral refuge, which stretches from Shimoni, 50 miles south of Mombasa, in Kenya to Dar es Salaam in Tanzania, is fed by cool water from deep channels formed thousands of years ago by glacial runoff from Kilimanjaro and the Usambara mountains. Outside that area, the corals are bleached and dying. But inside the area, of around 400 sq km [150 sq miles] they retain their colour and their health.

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.

Andrew A Shantz places an enclosure over corals on the sea floor at Florida Keys.

Selective fishing of larger parrotfish lets algae flourish

Scientists at Pennsylvania State University and the University of California, Santa Barbara have discovered that when fishermen selectively catch large and medium-sized parrotfish at coral reefs facing decline due to climate change, algae has a better chance of growing and overtaking the corals.

Nonetheless, according to the research, the reef’s biomass is maintained. This is because even with less of the large and medium-sized parrotfish, there would be many smaller parrotfish that would take their place.

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.