New ways warming water and bleaching damage reefs

Warmer ocean waters that bleach reef corals can fundamentally change the makeup of the reef, maybe permanently.

That change will dictate what our reefs will be like in the future, according to researchers writing in the journal Science.

(Image: Starfish surrounded by decomposing coral on the Great Barrier Reef. Credit: XL Catlin Seaview Survey)

Reef-building corals are complex communities, and the more we study them, the deeper the complexity goes.

A reef coral head isn’t a single entity, but a colony of coral animals called polyps. They lay down a calcium skeleton, which forms much of the rocky part of the reef. Each polyp is host to marine plants called zooxanthellae, which conduct photosynthesis and help feed the polyp. But there’s more. It turns out corals also support a community of smaller life forms, a microbiome of bacteria that, once again, both support and are supported by the coral community.

Researchers Tracy Ainsworth of James Cook University in Australia and Ruth Gates  of the Hawai`i Institute of Marine Biology at the University of Hawai`i, write in the June 24 issue of Science that climate change and coral bleaching events dramatically change that microbiome. Their article is entitled, “Corals’ microbial sentinels: The coral microbiome will be key to future reef health.”

“Corals that survive the multiple impacts of climate change and local disturbance will form the basis of future reefs that will differ in fundamental ways from those considered healthy today,” they write.

Corals are accustomed to a range of ocean temperatures. When the water temperature rises beyond that range, the corals lose their algal partners, which leaves them looking white and “bleached.”

That process also causes changes in the collection of bacteria that form part of the reef’s life, and that can further weaken coral polyps.

“The drastic impact of bleaching on the coral animals and, ultimately, its microbiome, can influence the immune system, alter the metabolic capacity and impair the stress resistance of the surviving corals,” Ainsworth and Gates write.

Since some of those bacteria are critical to the health of the corals, their disappearance can increase things like tissue death and disease. The community of corals, alga and bacteria may reach a new steady stage, but it may be a very different community after significant bleaching events occur, the authors write.

“The emergency of new ecosystem norms on coral reefs will be underpinned by changes to the microbiome and the microbial contribution to organism health and stress resistance, under new environmental norms,” they write.

© Jan TenBruggencate 2016

New ways warming water and bleaching damage reefs

Warmer ocean waters that bleach reef corals can fundamentally change the makeup of the reef, maybe permanently.

That change will dictate what our reefs will be like in the future, according to researchers writing in the journal Science.

(Image: Starfish surrounded by decomposing coral on the Great Barrier Reef. Credit: XL Catlin Seaview Survey)

Reef-building corals are complex communities, and the more we study them, the deeper the complexity goes.

A reef coral head isn’t a single entity, but a colony of coral animals called polyps. They lay down a calcium skeleton, which forms much of the rocky part of the reef. Each polyp is host to marine plants called zooxanthellae, which conduct photosynthesis and help feed the polyp. But there’s more. It turns out corals also support a community of smaller life forms, a microbiome of bacteria that, once again, both support and are supported by the coral community.

Researchers Tracy Ainsworth of James Cook University in Australia and Ruth Gates  of the Hawai`i Institute of Marine Biology at the University of Hawai`i, write in the June 24 issue of Science that climate change and coral bleaching events dramatically change that microbiome. Their article is entitled, “Corals’ microbial sentinels: The coral microbiome will be key to future reef health.”

“Corals that survive the multiple impacts of climate change and local disturbance will form the basis of future reefs that will differ in fundamental ways from those considered healthy today,” they write.

Corals are accustomed to a range of ocean temperatures. When the water temperature rises beyond that range, the corals lose their algal partners, which leaves them looking white and “bleached.”

That process also causes changes in the collection of bacteria that form part of the reef’s life, and that can further weaken coral polyps.

“The drastic impact of bleaching on the coral animals and, ultimately, its microbiome, can influence the immune system, alter the metabolic capacity and impair the stress resistance of the surviving corals,” Ainsworth and Gates write.

Since some of those bacteria are critical to the health of the corals, their disappearance can increase things like tissue death and disease. The community of corals, alga and bacteria may reach a new steady stage, but it may be a very different community after significant bleaching events occur, the authors write.

“The emergency of new ecosystem norms on coral reefs will be underpinned by changes to the microbiome and the microbial contribution to organism health and stress resistance, under new environmental norms,” they write.

© Jan TenBruggencate 2016

Eastern Polynesians made long canoe voyages right into the time of European exploration

Is it possible that the most important trade goods in the Polynesian Pacific were blocks of rock?

Increasing evidence indicates that stone tools and tool blanks were carried during numerous heroic long-distance canoe voyages, and that those voyages continued at least into the period when Europeans appeared in the Pacific.

Perhaps the more important message of the traveling stones is that the Eastern Polynesian island communities stayed connected for centuries after initial colonization. 

“In East Polynesia, long-distance interaction between island societies was a fundamental colonization strategy linking parent with multiple daughter communities to support the establishment of socially and economically viable groups,” says a new report in PNAS, the Proceedings of the National Academy of Sciences. 

The authors of “Cook Island artifact geochemistry demonstrates spatial and temporal extent of pre-European interarchipelago voyaging in East Polynesia” include an international set of geological and anthropolical superstars: Marshall Weisler, Robert Bolhar, Jinlong Ma, Emma St Pierre, Peter Sheppard, Richard K. Walter, Yuexing Feng, Jian-xin Zhao, and Patrick V. Kirch.

They report on the provenance of stone adzes and associated materials found in a venerable rock shelter on the Cook Islands island of Mangaia. The shelter is called Tangatatau, and it was used for hundreds of years. The stone adzes were found in layers of sediment that could be dated.

Here is a report on the research from the Australian network, ABC. 

Researchers have known for some time that adzes did a lot of traveling. We reported in 2007 on an adze found in the Tuamotu chain, which came from an adze quarry on Kaho`olawe, in Hawai`i.

So it was, perhaps, not surprising that the Mangaia rock shelter had adzes from around the eastern Pacific. Some sources were just a few hundred miles away, in the Cooks and the Austral Islands, but there was also material that could be linked to quarries in Samoa and the Marquesas—more than 1,000 miles away. Those were significant distances, and there were indications of repeat voyages.

The Samoan connection is notable because Samoa is considered part of West Polynesia. It is considered the jumping-off point for inhabitation of the Eastern Pacific Islands (Tahiti, Marquesas, Hawaii, Cooks, Australs. Rapa Nui, Pitcairn, etc.) And until now, it was assumed that contact between West and East Polynesia died out early, allowing the Eastern Polynesian culture to develop on its own. 

“This evidence for continued voyaging contact between the Cook Islands and Samoa is … of considerable import because it has often been tacitly assumed that there was little or no contact between the island groups of East Polynesia and the West Polynesian homeland region, after the initial settlement of East Polynesia,” the authors write.

Another issue is why is all the stone tool voyaging only brought tools into Mangaia, and not the other way. Why were the Marquesas, Samoa and the Australs entirely exporters of stone, and Mangaia entirely an import culture?  Or will further archaeology show it was a two-way transport?

Two big questions: Why did the voyaging continue for so long? And why did it end?

Here’s how Weisler and his team answer the first question.

“Postcolonization voyaging and interaction supported socially mediated imperatives such as the acquisition of high status goods, the fostering and maintenance of strategic alliances, and establishing individual and group prowess or ‘mana.’”

They assume some ceremonial component, since Mangaia has its own adz quarries, unlike the Tuamotu archipelago, where most islands are atolls and hard basalt rock is difficult to acquire. Mangaia didn't need the stone, but still, voyagers brought the stone.

The authors don’t have a ready answer for the second question—why the voyaging stopped. There is indication that the most distant island groups dropped out of the trade web earliest. Hawai`i is by far the most distant group from the others, and its presence in the artifacts of the South Pacific thus far has only been established by the one adze found on the Tuamotu atoll of Napuka, 2,500 miles from Kaho`olawe.

The researchers of the Mangaia stone tools report that materials continued to flow in a one-way pattern into Mangaia for as long as 300 years.

“A large corpus of radiocarbon age determinations and associated imported adze material from Tangatatau documents the time span of interarchipelago voyaging from the early AD 1300s to at least the 1600s,” they wrote.

The paper does not address it, but there was something else happening in the Eastern Pacific about the time of the end of voyaging. 

European ships were appearing.

The Portuguese explorer Magellan came through the Pacific from east to west in 1520, although he missed Polynesia and made his first landfall on Guam. 

The Marquesas were visited perhaps as early as 1526 by the Spanish, and were given their European name by Spanish explorer Alvaro de Mendana in 1595. De Mendana also spotted Pukapuka in what would be the Cook Islands. His navigator de Quiros was in the Tuamotu in 1606, and walked on the Cooks’ Rakahanga shortly afterward. 

The Dutch were in the region in 1616 (Schouten and Le Maire), 1643 (Tasman) and again in 1722 (Roggeveen). 

The British didn’t show up until the late 1700s, but ended up spending more time in Eastern Polynesia than any of the others. Capt. James Cook spotted Mangaia in 1777, the year before he sailed into Hawai`i.

But it was the Polynesian voyaging era that was the most historic. The Europeans came through in discovery vessels. But the Polynesians migrated. They brought their whole culture and created new island communities.

“Oceania, the last region settled on Earth, witnessed the greatest maritime migration in human history,” wrote authors of the Mangaia stone artifact study.

© Jan TenBruggencate 2016

Another set of Kauai drinking water quality tests, another clean bill of health

The Kauai Department of Water’s latest water quality reports reconfirm its earlier indications that pesticide and chemical contamination of drinking water is rare on Kauai.

Where it exists it is primarily from old agricultural or non-agricultural sources.

The testing confirms what county water officials have asserted for years--that the drinking water that feeds the county's water systems is extremely low in contaminants, and that most of those contaminants are from natural sources and things like corrosion of household plumbing systems.

"Our drinking water meets, or is better than, state and federal standards. We spend in excess of $400,000 in chemical and microbial testing each year to assure the safety of your water," the department said in its water quality report.

It seems to be just another confirmation of what the Kauai Pesticide Joint Fact Finding study found about chemical contamination of our community—nothing much.

The newest water studies—for 2015—are available for all Kauai communities served by the county on the Department of Water website.

The Water Department tests regularly for dozens of regulated and unregulated chemicals in drinking water.

In the West Kauai community of Waimea-Kekaha, which has been decried by some as “ground zero” for pesticide “drenching,” no pesticides at all were detected. All inorganic compounds detected are from natural soil erosion, although low levels of nitrates could be from leaking septic systems or from agricultural or residential fertilization. Nitrate levels were at less than a third of the EPA’s concern level.

Total trihalomethane, a byproduct of drinking water chlorination, was found at less than 10 percent the concern level. Lead and copper were also detected at levels below the action level—and they are believed to be from residential plumbing system corrosion.

The Hanapepe-Eleele system had similar results, with no pesticides other than water chlorination residue. The Kalaheo-Koloa system was similar again, with one exception. It showed below-action-level detection of trichloropropane, a soil fumigant also used in industrial applications like dry cleaning and as a solvent.

The Lihue-Kapaa system had a number of chemical detections, including those listed above. The tests found low levels of bromochloromethane, a fire retardant, and remnants of two pesticides, DCPA, which is used in weed control of vegetable crops, and dioxane, an industrial chemical and pesticide.

Both were measured at a fraction of a part per billion, with some samples undetectable.

Anahola’s water system was similar to Waimea-Kekaha’s, with chemicals from home plumbing systems, from natural soil and rock erosion, chlorination byproducts and very low levels of nutrients that could come from waste disposal systems or fertilizer runoff. 

Kilauea and the other North Shore Department of Water systems had generally lower levels than the already low levels of other areas. 

The reports are generally in line with a series of tests conducted earlier this year at the insistence of County Councilman Gary Hooser, who repeatedly demanded the department conduct specialized testing for the pesticide chlorpyrifos.

The Department of Water had informed Hooser that chlorpyrifos was an unlikely contaminant in groundwater, because it degrades quickly and because it is applied to the plant and not to the ground. The department noted that the University of Hawai`i and Department of Health had determined that chlorpyrifos is unlikely to leach into water. 

In spite of the department’s assertion, and after his second demand, the Department of Water in March 2016 conducted the tests and, as expected, found zero detectable chlorpyrifos in the four Kaua`i water systems tested.

They tested the water systems most likely to be exposed to chlorpyrifos—wells in Mana, Waimea and Lihue, and the Kapaia surface water treatment system. As an additional precaution, they asked their testing lab to conduct another kind of test for a series of pesticides, including chloryprifos. Once again, no detectable levels were found, the department reported.

The Department of Water response, the test results and Hooser’s letters can be found here.

Agricultural chemical detection in groundwater was more common decades ago, during the years when major sugar and pineapple farming were active, and in the years thereafter. Many of the chemicals that were at detectable levels then are no long being detected.

© Jan TenBruggencate 2016