A day is the time for Earth to make one complete rotation on its axis, a year is the time for Earth to make one revolution around the Sun — reminders that basic units of time and periods on Earth are intimately linked to our planet’s motion in space relative to the Sun. In fact, we mostly live our lives to the rhythm of these astronomical cycles.

The same goes for climate cycles. The cycles in daily and annual sunlight cause the familiar diel swings in temperature and the seasons. On geologic time scales (thousands to millions of years), variations in Earth’s orbit are the pacemaker of the ice ages (so-called Milanković cycles). Changes in orbital parameters include eccentricity (the deviation from a perfect circular orbit), which can be identified in geological archives, just like a fingerprint.

The dating of geologic archives has been revolutionized by the development of a so-called astronomical time scale, a “calendar” of the past providing ages of geologic periods based on astronomy. For example, cycles in mineralogy or chemistry of geologic archives can be matched to cycles of an astronomical solution (calculated astronomical parameters in the past from computing the planetary orbits backward in time). The astronomical solution has a built-in clock and so provides an accurate chronology for the geologic record.

However, geologists and astronomers have struggled to extend the astronomical time scale further back than about fifty million years due to a major roadblock: solar system chaos, which makes the system unpredictable beyond a certain point.

In a new study published in the journal Science, SOEST oceanography professor Richard Zeebe and Lucas Lourens from Utrecht University now offer a way to overcome the roadblock. The team used geologic records from deep-sea drill cores to constrain the astronomical solution and, in turn, used the astronomical solution to extend the astronomical time scale by about 8 million years. Further application of their new method promises to reach further back in time still, one step and geologic record at a time.

On the one hand, Zeebe and Lourens analyzed sediment data from drill cores in the South Atlantic Ocean across the late Paleocene and early Eocene, ca. 58-53 million years ago (Ma). The sediment cycles displayed a remarkable expression of one particular Milanković parameter, Earth’s orbital eccentricity. On the other hand, Zeebe and Lourens computed a new astronomical solution (dubbed ZB18a), which showed exceptional agreement with the data from the South Atlantic drill core.

“This was truly stunning,” Zeebe said. “We had this one curve based on data from over 50-million-year-old sediment drilled from the ocean floor and then the other curve entirely based on physics and numerical integration of the solar system. So the two curves were derived entirely independently, yet they looked almost like identical twins.”

Zeebe and Lourens are not the first to discover such agreement — the breakthrough is that their time window is older than 50 Ma, where astronomical solutions disagree. They tested 18 different published solutions but ZB18a gives the best match with the data.

The implications of their work reach much further. Using their new chronology, they provide a new age for the Paleocene-Eocene boundary (56.01 Ma) with a small margin of error (0.1%). They also show that the onset of a large ancient climate event, the Paleocene-Eocene Thermal Maximum (PETM), occurred near an eccentricity maximum, which suggests an orbital trigger for the event. The PETM is considered the best paleo-analog for the present and future anthropogenic carbon release, yet the PETM’s trigger has been widely debated. The orbital configurations then and now are very different though, suggesting that impacts from orbital parameters in the future will likely be smaller than 56 million years ago.

Zeebe cautioned, however, “None of this will directly mitigate future warming, so there is no reason to downplay anthropogenic carbon emissions and climate change.”

Regarding implications for astronomy, the new study shows unmistakable fingerprints of solar system chaos around 50 Ma. The team found a change in frequencies related to Earth’s and Mars’ orbits, affecting their amplitude modulation (often called a “beat” in music).

“You can hear amplitude modulation when tuning a guitar. When two notes are nearly the same, you essentially hear one frequency, but the amplitude varies slowly — that’s a beat,” Zeebe explained. In non-chaotic systems, the frequencies and beats are constant over time, but they can change and switch in chaotic systems (called resonance transition). Zeebe added, “The change in beats is a clear expression of chaos, which makes the system fascinating but also more complex. Ironically, the change in beats is also precisely what helps us to identify the solution and extend the astronomical time scale.”

Read more on Discover Magazine, Scientific American, Phys.org and UH News.

The University of Hawaiʻi Sea Grant College Program recently released the Guidance for Disaster Recovery Preparedness in Hawaiʻi (PDF), a publication to help coastal communities plan to recover from disasters before they strike.

The guidance document is intended to help state and county agencies establish recovery practices and protocols before a disaster hits. Its guidance will enable communities to recover quickly while also improving resilience to future disasters, adapting to climate change and sea-level rise, and protecting sensitive environments.

“It is no secret that our shorefront development is highly vulnerable to hurricanes and other events. Impacts from flooding, high waves and erosion will worsen in coming decades with sea level rise and other climate change related effects,” said project leader Brad Romine, Sea Grant coastal management and resilience specialist. “Our emergency management agencies are well-prepared and have worked tirelessly in their response to recent disasters. However, we need to improve our preparedness, particularly for longer-term recovery and rebuilding following a disaster.”

Read more about it in the UH System News.

Research conducted at the University of Hawaiʻi (UH) at Mānoa School of Ocean and Earth Science and Technology (SOEST) on a marine sponge in Kāneʻohe Bay, Oʻahu revealed a unique feeding strategy, wherein the sponge animal acquires important components of its diet from bacteria living within the sponge.

Coral reefs are one of Hawaiʻi’s most important natural resources and support fisheries and the state’s economy. Marine sponges are important components of coral reef ecosystems, but in Hawaiʻi, the Indo-Australian sponge Mycale grandis is an invasive alien species that was only first documented in the islands in the late 1990s. M. grandis is now found in and near major harbors of the Main Hawaiian Islands as well as within Kāneʻohe Bay.

In a study led by Dr. Joy Leilei Shih for her doctoral research at UH Mānoa, the diet of M. grandis sponges collected from Kāneʻohe Bay was elucidated by using a new application of a technique that relies on naturally occurring stable isotopes to understand the origin of specific compounds in the tissues of plants and animals.  In this case, the team tested where amino acids, the building blocks of proteins in tissues, in the sponge came from. Did they originate from food caught and filtered from seawater or were they supplied to the sponge from the microbes living within the sponge itself?

When one organism consumes another, elemental properties in the prey are conserved and leave behind a unique chemical pattern with the predator. By assessing the chemical difference between predator and prey tissues, Shih and colleagues found the diet of sponges did not originate from photosynthesizing microbes (such as seen in corals) and M. grandis feeding did not follow general patterns of other multicellular animals.  Instead, the isotopic patterns of the sponge and its symbiotic microbes were not different from one another, indicating the sponge obtains nutrition through the uptake of amino acids originating from their symbiotic microbes.

“While we knew that the symbionts of sponges play an important role in their diet, the mechanism by which it occurred was unknown,” said Shih. “The only way to produce the observed amino acid isotopic pattern, or fingerprint, if you will, is through the direct transfer of amino acids from their symbiotic bacteria.”

“The patterns we detected in M. grandis and its symbionts are very interesting, as they suggest sponges may be actively capturing materials in seawater to support the needs of their microbial community, which in turn supply the sponge with essential tissue building blocks,” said Dr. Chris Wall, a postdoctoral researcher at UH Mānoa and a co-author on the study.

“The symbiosis we see between the sponge and its microbial community is remarkable,” said Shih. “The intimate relationship between sponges and their symbionts developed over their long evolutionary history. Sponges are the oldest multi-cellular animal on earth. That’s why they are so well-adapted and resilient.”

The researchers’ new approach to investigating sponge feeding strategies can be applied to future research on other marine sponges in Hawai‘i and elsewhere.  Sponges play an important role in the nutrient dynamics of coral reefs, and in the future, sponges may rise to dominate coral reefs as corals decline from direct pressure from human activity and climate change. This work can help policymakers design better informed conservation plans and provides new insights into the biology of sponges and shows the importance of marine microbes to the diet of an invasive sponge.

Read also on The Scientist and Science Daily.

New research, led by University of Hawai‘i (UH) at Mānoa scientists and published today in the journal Nature Climate Change, has found that Antarctic icebergs can weaken and delay the effect of global warming in the Southern Hemisphere.

Unabated global warming threatens the stability of the Antarctic ice sheet. Ice loss can occur in the form of melt-induced (liquid) freshwater discharge into the ocean, or through ‘calving’, the release of icebergs from ice shelves. Recent observations reveal a rapid thinning of the Pine Island and Thwaites glacier regions in Antarctica, which can be attributed partly to warming oceans. These findings have raised concerns of an accelerated ice loss of the West Antarctic ice sheet and potential contributions to global sea level rise.

Climate researchers at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), the IBS Center for Climate Physics (South Korea), Penn State University and University of Massachusetts have quantified for the first time the effect of Antarctic iceberg calving on future Southern Hemisphere climate.

The team ran a series of global warming computer simulations, which included the combined freshwater and cooling effects of icebergs on the ocean. The size and number of icebergs released in their model mimics the gradual retreat of the Antarctic ice sheet over a period of several hundred years. By turning on and off the “iceberg effect” in their climate model, the researchers discovered that icebergs can significantly slow down human-induced warming in the Southern Hemisphere, impacting global winds and rainfall patterns.

“Our results demonstrate that the effect of Antarctic melting and icebergs needs to be included in computer model simulations of future climate change. Climate models currently used in the 6^th climate change assessment of the Intergovernmental Panel on Climate Change (IPCC) do not account for this process,” said Fabian Schloesser, researcher at UH Mānoa SOEST and lead author of the study.

With projected future shrinking of the Antarctic ice sheet, scientists expect an intensification of iceberg discharge. Icebergs can persist for years and are carried by winds and currents through the Southern Ocean until they reach warmer waters and ultimately melt. The melting process cools ocean waters like ice cubes in a water glass. Furthermore, freshwater discharge from icebergs impacts currents by lowering ocean salinity. Whether this “iceberg effect’’ can slow down or alter future climate change in the Southern Hemisphere has remained an open question.

Melting icebergs takes massive amounts of energy—energy that is taken from the ocean as heat, which slows down warming in parts of the Southern Hemisphere.

Tobias Friedrich, SOEST researcher and co-author of the study, added, “To melt the icebergs released over the 21^st century in one of our extreme Antarctic ice-sheet retreat scenarios would require 400 times the current annual world energy consumption. Global sea level would rise by about 80 cm, impacting many coastal regions and communities worldwide.”

Previous studies have suggested that the impact of Antarctic meltwater discharge on the ocean could lead to further acceleration of ice sheet melting and global sea level rise. The present study paints a more complex picture of the underlying dynamics. Including the cooling effect of icebergs largely compensates for the processes that were previously thought to accelerate Antarctic melting.

“Our research highlights the role of icebergs in global climate change and sea level rise. Depending on how quickly the West Antarctic ice sheet disintegrates, the iceberg effect can delay the effects of global warming in cities such as Buenos Aires and Cape Town by 10-50 years,” said Axel Timmermann, corresponding author of the study and director of the IBS Center for Climate Physics.

The research team plans to further quantify the interplay between ice and climate and its effect on global sea level with a new computer model that they developed.

Read more on Hawaii Public Radio and UH News.

August 1, 2019 marks a transition to new leadership for one of the longest running open ocean research programs in the world. Angelicque White, a newly-hired oceanography associate professor at the University of Hawai‘i (UH) at Mānoa School of Ocean and Earth Science and Technology (SOEST) will lead the next chapter of the monumental Hawai‘i Ocean Time-series (HOT) program.

In 1988, with focus on the biology and chemistry of the open ocean north of the Hawaiian Islands, the HOT program was established by David Karl and Roger Lukas, both professors of oceanography in SOEST. The initiation of the program was in response to a recognized lack of scientific understanding of the structure, dynamics, and controls on major biogeochemical cycles in the sea, especially the carbon cycle.

For more than 30 years, the HOT program has provided consistent, long-term observations of physical, biological and chemical properties of the open ocean in the North Pacific Subtropical Gyre and has led to many discoveries in marine ecology and ocean and climate sciences.

In a ceremony to commemorate the transition, Karl, White and a group of past and present HOT faculty, staff and students; captain and crew of UH research vessels; and SOEST administration gathered at the UH Marine Center prior to the departure of the 314^th cruise of the HOT program. Past and current members of the program spoke of the breadth of scientific findings made possible by the program and the educational and personal importance of their involvement in the time-series.

“Science is a team sport, and we have assembled the best team on the planet to address research with great scientific and societal relevance—research that matters!” said Karl in his opening remarks.

“Sustained observation of our planet is a moral imperative for our generation and those to come.  I am proud to lead this program forward with an incredible team at my side,” said White during the ceremony.

White will lead this next chapter of the program, SOEST researcher James Potemra will be a co-investigator and, for the next four years, Karl will remain with the program as co-investigator.

The HOT program receives primary funding from the U.S. National Science Foundation (NSF) in partnership with the Simons Foundation, the Gordon and Betty Moore Foundation and the State of Hawai‘i.

Whether the next two storms come close, it’s not too early to take the necessary precautions to protect yourselves and your property. An expert says little things that you do now or ahead of time can go a long way in preventing rain and wind damage.

Heavy rain during a storm can not only flood your home but can also lead to tragedy. So keeping water away from your property is a priority. Something as simple as cleaning out your rain gutters is an important preparation for upcoming storms.

“A lot of times there’s leaves or other debris that collect in gutters. It clogs, once it clogs up and it starts raining they get heavy and they’re likely to collapse,” said Dennis Hwang from the University of Hawai‘i Sea Grant College Program.

Once the rain gutters collapse, the pieces of metal can also fly around like projectiles to cause more damage. Hwang, who is the co-author of the Homeowner’s Handbook to Prepare for Natural Hazards, says homeowners should also clear drainage paths leading out of your property.

As for the winds, Hwang says the best protection is making sure you have hurricane clips, which attach your walls to the roof. To protect your windows, install storm panel screws well ahead of time so you can put the plywood on quickly when needed. “The key is to do this beforehand. It takes one hour to prepare each panel but once you’re prepared it takes five minutes to put up,” said Hwang.

UPDATE: Read more about it and watch the video reports at KHON2: an initial overview and a more detailed preparedness report.