VIMS research helps clarify role of water clarity in coastal management

Choice of water-clarity metrics impacts management of seagrasses and other light-loving organisms

Peer-Reviewed Publication

VIRGINIA INSTITUTE OF MARINE SCIENCE

 

IMAGE: DR. JESSIE TURNER DEPLOYS A SECCHI DISC INTO THE YORK RIVER FROM THE SEAWATER RESEARCH LAB PIER AT THE VIRGINIA INSTITUTE OF MARINE SCIENCE. © DAVID MALMQUIST/VIMS. view more 

CREDIT: DAVID MALMQUIST

Secchi disks & light sensorsWater clarity is key to the health and restoration of marine plants and animals worldwide, particularly in shallow coastal systems such as the Chesapeake Bay. But it turns out that measuring water clarity isn’t as clear-cut as it might appear.

Research at the Virginia Institute of Marine Science led by Dr. Jessie Turner reveals that the “clarity” of a water parcel depends on the method used to measure it, and that different research questions and management decisions merit different clarity-measuring tools and techniques. Turner and her co-authors, Drs. Kelsey Fall and Carl Friedrichs, lay out their recommendations in a recent article in Limnology and Oceanography Letters. 

“In coastal and inland waters,” says Turner, “the methods we use to gauge water clarity can misrepresent the underwater light climate used to determine restoration goals, such as the potential habitat available for underwater grasses. It’s thus really important to choose the most appropriate measurement method, and to clearly communicate the method used. Not all water-clarity metrics are created equal.”

Underwater grasses serve many key ecological functions and are among the most closely monitored habitats in the Bay. They provide food and shelter for numerous marine species, help oxygenate the water, and can mitigate global warming by removing carbon dioxide from the air. To do so, they need clear water for photosynthesis and growth. Their dependence on clear water makes them a “canary in the coal mine” for water clarity in shallow coastal systems.

Turner (VIMS Ph.D. ’21) is currently a postdoctoral research associate at the University of Connecticut. Fall (VIMS Ph.D. ’20) is now at the U.S. Army Engineer Research and Development Center in Vicksburg, Mississippi. Friedrichs is Glucksman Professor in William & Mary’s School of Marine Science at VIMS and Associate Director of the Chesapeake Bay National Estuarine Research Reserve in Virginia.

Water and beer

To explain the complexities of water clarity and its measurement, Turner turns to an analogy with beer—another liquid whose “clarity” is of widespread interest. Ironically, the scientific principle used to define the clarity of beer and other liquids is known as Beer’s Law (ironic as the principle was first applied to wine, not beer, and doubly so as the law is named after German chemist August Beer, not the hoppy beverage).

“Beer's Law tells us that how much light gets through a liquid depends on the concentration of stuff in the liquid and the distance over which you're measuring,” says Turner. 

What’s the “stuff?” “In beer,” she says, “it’s either particles like yeast and hops, or dissolved things like sugar or tannins from the brewing process. In Chesapeake Bay, the “stuff” can be particles such as tiny pieces of dirt and microscopic plants, or dissolved organic matter and other solutes.” Dissolved organic matter is an earthy tea steeped from leaf litter, crop residue, soil, and other carbon-based materials from the Bay and its watershed.

Crucially, particulate matter and dissolved substances impede light in different ways. “When light hits water or beer it can either get scattered, or it can get absorbed,” says Turner. “Particles scatter light, dissolved substances absorb light.”

The relative abundances of particulate and dissolved materials combine to produce different light environments. In areas of Chesapeake Bay with high levels of both light-scattering particles and light-absorbing solutes, the water is dark like a stout. In areas with lots of light-scattering particles but few light-absorbing solutes, the water is cloudy yet bright, like a hazy ale. Areas with few particles or solutes are clearest, like a cider.

As with water in the Chesapeake Bay and other aquatic ecosystems, the clarity of different beers depends on their concentrations of dissolved and particulate matter.

CREDIT

© David Malmquist/VIMS.

Secchi disks & light sensors

These differences have important ramifications when considered in light of the multiple tools and techniques scientists use to measure water clarity. Two common optical tools are Secchi disks and light sensors. Scientists also directly measure the concentration of suspended particles, dissolved materials, and chlorophyll (the pigment that plants and plankton use to capture sunlight for photosynthesis).

“A Secchi disc is a simple black-and-white disc that you lower horizontally through the water,” explains Turner. “The depth at which it disappears from view is known as the Secchi depth.” This cheap, easy-to-deploy, and long-used tool measures water transparency and the depth of object visibility. 

Light sensors measure the loss or attenuation of sunlight as it penetrates deeper into the water, with a focus on the wavelengths plants use for photosynthesis. Recorded values are compared to those collected by a surface sensor to account for differences in incoming light due to clouds and time of day. 

Though advances in electronics and materials have reduced the cost and increased the use of light sensors, Secchi discs remain the everyday workhorse of many water-clarity studies, both by professional researchers and a growing cadre of community scientists.

Problems arise, according to Turner and her co-authors, when practitioners apply a traditional one-size-fits-all equation to estimate light attenuation from Secchi depth values. That’s because the relationship between these two metrics can vary greatly depending on the local light climate—whether an underwater study site is dark like a stout, bright yet cloudy like an ale, or clear like a cider.

“The relationship between these two metrics can vary widely between and within estuaries and other aquatic environments based on latitude, hydrology, and climate,” says Turner. “Using a single conversion factor to estimate light attenuation based on Secchi depth can thus either under- or overestimate the underwater light climate.”

For example, in the turbid waters of the York River, a major Chesapeake Bay tributary, use of the traditional conversion factor would underestimate the light available for seagrasses, and thus short-sell potential restorations targets.

Recommendations

To counter this and related difficulties, Turner and colleagues recommend several changes in how water clarity is measured and reported. Most important is to clearly communicate the method used—whether a Secchi depth from a Secchi disk, light attenuation, or another method.

For studies related to underwater grasses and other light-loving organisms, the authors advise colleagues to collect light-attenuation values directly.

“Measures of light attenuation with depth are most relevant for most research in aquatic ecosystems,” says Turner. “They are well-suited to research involving underwater grasses, kelp, and corals, as these and other similar organisms are adapted to harvest downwelling light.” The authors recommend use of a separate, “scalar” measure of light attenuation when studying phytoplankton, which as floating organisms can harvest light from all directions, both downwelling and scattered from the side and below.

If cost concerns or other factors encourage use of Secchi discs, the authors advise researchers to forgo use of the traditional one-size-fits-all equation, recommending instead they calibrate the Secchi-depth to light-attenuation formula using localized measures. “The equation needs to be locally calibrated because the characteristics of the water’s dissolved and particulate matter vary greatly, sometimes over very short distances,” says Turner. “These characteristics can also vary seasonally.”

Because Secchi depth values measure visibility and transparency, the authors say their direct application is most appropriate for studies of fish and other visual predators. They note they are also of value in a human context, in areas such as in-water recreation and the value of coastal property and viewscapes.

Whatever methods a research team might use, the authors urge them to select the most useful metric or metrics according to the specific research question or management goal.

“When relevant to the goal,” says Turner, “even the simplest water clarity measurements are valuable for environmental monitoring and restoration, whether collected by scientific sampling programs, non-profit organizations, or community scientists.”

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JOURNAL

Limnology and Oceanography Letters

DOI

10.1002/lol2.10301 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

Smaller fishes in the deep ocean to be expected with ocean warming

This is the main conclusion of a new study involving the ICM-CSIC based on the analysis of fish otoliths found in geological formations dating back 700-800 thousand years

Peer-Reviewed Publication

INSTITUT DE CIÈNCIES DEL MAR (ICM-CSIC)

A new study led by the University of Vienna in which the Institut de Ciències del Mar (ICM-CSIC) has participated reveals that fishes living in the dark part of the oceans (essentially below 200 m depth in the water column) would likely decrease in size with climate warming, which may have important ecological effects.

The details of this research are reported in an article published today in Proceedings of the Royal Society B. For its preparation, the authors retrieved fish otoliths — small stones in the inner ear of bony fishes that facilitate the fishes’ sound and balance perception — from sedimentary formations dated 800–700 thousand years ago from the island of Rhodes in the Aegean Sea and measured them to track changes in fishes’ body size through glacial and interglacial periods.

The morphology of these structures is particular to each fish species and their size directly reflects the size of the fish individual they come from, which allows researchers to identify them in order to reconstruct past fish faunas.

“Thanks to the otolith analysis we have found that fishes during the interglacial period were smaller in size by 35%, when the global temperature had increased by 4 °C, which could happen again nowadays due to the ocean warming”, explains the leading author of the study, Konstantina Agiadi, from the University of Vienna.

Small fishes, big impacts

The study, that is one of the few works that have so far addressed the consequences of climate warming on the deeper part of the oceans, the mesopelagic zone (200–1000 m depth), focused on the changes in “lanternfishes”, a group of small mesopelagic fishes that are named for their capacity to produce their own light.

“Knowing the response of these organisms to ocean warming is key, since they contribute to ecosystem stability, reduce atmospheric carbon dioxide, and are a huge food resource for other organisms in the marine food web”, explains the ICM-CSIC researcher and co-author of the study Marta Coll, who adds that “these fish make up more than half the fish biomass in the deep sea, and about 100 times more than the total global annual fishery catches”.

Lately, lanternfishes are important contributors to the biological carbon pump, a natural mechanism for reducing atmospheric carbon dioxide (CO2). Initially, phytoplanktonic organisms absorb CO2 from the atmosphere through photosynthesis. Then, every night, lanternfishes travel hundreds of meters upward to the surface of the oceans and return to the mesopelagic zone, thus bringing huge amounts of carbon from the surface to the deep ocean.

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JOURNAL

Proceedings of the Royal Society B Biological Sciences

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Palaeontological evidence for community-level decrease in mesopelagic fish size during Pleistocene climate warming in the eastern Mediterranean

ARTICLE PUBLICATION DATE

11-Jan-2023

AND WHERE TO AVOID PUTTING WINDTURBINES

New map of “stopover hotspots” provides insights for conservation of eastern US migratory landbirds

Peer-Reviewed Publication

PRINCETON SCHOOL OF PUBLIC AND INTERNATIONAL AFFAIRS

Every autumn, billions of birds migrate across the eastern U.S. en route to their wintering sites. As the birds undertake their journeys, however, they are faced with increasing threats, including habitat loss, storms, feral cats and other predators, pesticides, collisions with buildings, and climate change. Not only are individual species impacted by these threats, but so is the migratory phenomenon itself.

A new study published in the journal Proceedings of the National Academy of Sciences presents the first comprehensive map of autumn stopover hotspots of landbirds for the eastern United States. Stopover sites are locations where birds pause between migratory flights in order to rest and refuel before resuming their journeys. The new map created by the researchers can inform where conservation efforts would be most effective.

“This is the first time we’ve had a comprehensive picture of where songbirds are stopping over for the entirety of the eastern United States,” said David Wilcove, professor of Public Affairs and Ecology and Evolutionary Biology and the High Meadows Environmental Institute and a co-author on the study. “It gives us a powerful new tool for identifying the key habitats these birds are using during their epic migrations,” Wilcove said.

The researchers used data collected from a national network of weather radar stations to identify “stopover hotspots,” or sites that consistently support a high number of migratory birds year to year. Weather radar images capture not only precipitation but also migrating birds, but separating the birds from the precipitation (and other things) requires a great deal of image processing.

The study finds that landbirds migrate across a broad front through the eastern United States, with relatively more birds following the Mississippi River and, to a lesser extent, the Appalachian Mountains. By examining the migration at finer spatial scales, the researchers were able to identify hotspots that support high densities of birds from year to year on their migratory journeys.

The study also reports that at these finer scales, there are high concentrations of birds in the pockets of broadleaf forests remaining in areas that have been largely deforested to grow crops, such as the Midwest. Previously, these forest fragments were seen as having relatively little value for songbirds because they do not generally support large populations of them during the breeding season. But during the fall migration, they become important rest and refueling spots.

“Small pockets of deciduous forest are often neglected in conservation planning because birds have low breeding success in these spaces,” said Fengyi Guo, lead author of the study and a PhD candidate in the department of Ecology and Evolutionary Biology at Princeton University. “But the entire population moves across the continent twice annually. Many of them depend on food and shelter in these forest pockets to complete their migration” Guo said.

Another novel finding is that there are high concentrations of birds in the forests along the edge of the Midwest prairie region, now largely converted to farmland, suggesting that these farmlands may be an obstacle for migratory birds and that the birds are avoiding stopping over in the prairies until they reach more forested places, which provide more suitable habitat for them.

Taken together, the study suggests that a network of protected forested land distributed across the eastern US is key to maintaining healthy populations of migratory landbirds. The authors urge the protection of broadleaf forests, especially the remaining forests in the agriculturally dominated Midwest. Locally based conservation efforts across the eastern U.S. will be key to protecting bird species along their migratory journeys.

“A chain is only as strong as its weakest link. Successful conservation of migratory bird populations requires enough habitat to be protected at all stages of its annual cycle,” Guo said.

The paper, “Autumn stopover hotspots and multiscale habitat associations of migratory landbirds on the eastern U.S.,” was published January 9, 2023 in PNAS. The authors of the report are Fengyi Guo and David Wilcove (Princeton University) and Jeffrey Buler and Jaclyn Smolinsky (University of Delaware). The research was supported by the High Meadows Foundation and USDA NIFA Hatch.

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2203511120 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Autumn stopover hotspots and multiscale habitat associations of migratory landbirds in the eastern United States

ARTICLE PUBLICATION DATE

9-Jan-2023

Toxic toilet paper and long-lasting chemicals found in endangered killer whales

Peer-Reviewed Publication

UNIVERSITY OF BRITISH COLUMBIA

A chemical used in the production of toilet paper and 'forever chemicals' have been found in the bodies of orcas in B.C. , including the endangered southern resident killer whales.

The Institute for the Ocean and Fisheries at UBC, British Columbia Ministry of Agriculture and Food, and Fisheries and Oceans Canada scientists analyzed tissue samples from six southern resident killer whales and six Bigg’s whales stranded along the coast of B.C. from 2006 to 2018, according to a recent study. They discovered that chemical pollutants are prevalent in killer whales, with a chemical often found in toilet paper one of the most prevalent in the samples studied, accounting for 46 per cent of the total pollutants identified.

Called 4-nonylphenol or 4NP, the compound is listed as a toxic substance in Canada and can interact with the nervous system and influence cognitive function, the authors say. “This research is a wake-up call. Southern residents are an endangered population and it could be that contaminants are contributing to their population decline. We can’t wait to protect this species,” said co-author Dr. Juan José Alava, principal investigator of the ocean pollution research unit at the Institute for the Oceans and Fisheries (IOF).

4NP is often used in pulp and paper processing, as well as in soap, detergents and textile processing. It can leak into the ocean via sewage treatment plants and industrial runoffs, where it is ingested by smaller organisms and moves up the food chain to reach top predators such as killer whales. It’s known as a ‘contaminant of emerging concern’ or CEC, which are pollutants found in the environment that are not well-studied and so, regulated. “Very little is known of both the prevalence and health implications of 4NP as it has been studied in few marine mammals. This study is the first to find 4NP in killer whales,” said first author Kiah Lee, who undertook the research as an undergraduate at UBC.

“This investigation is another example of an approach that takes into account the health of people, animals and the environment, using killer whales as a case study to better understand the potential impacts of these and other compounds to animal and ecosystem health,” said co-author Dr. Stephen Raverty, IOF adjunct professor and veterinary pathologist with the B.C. Ministry of Agriculture and Food.

‘Forever chemicals’

Just over half the pollutants identified by the researchers belong to a group of compounds known as ‘forever chemicals’ because they last for a long time in the environment. They are widely used in food-packaging materials, stain and water-repellent fabrics, cookware, and fire extinguishers. Many are listed as new Persistent Organic Pollutants (POPs). These are toxic substances released into the environment through human activities that adversely affect the health of humans and animals. Many are banned in Canada.

The most common pollutant of this group the researchers found was 7:3-fluorotelomer carboxylic acid, or 7:3 FTCA. There are currently no restrictions on the production and use of 7:3 FTCA but one of its potential parent chemicals is on a list of toxic substances proposed to be recognized as new POPs by the European Chemical Agency under an international agreement, the Stockholm Convention on POPs.

“This compound has not been found in B.C. before and it was found in killer whales, which are top predators. That means the contaminants are making their way through the food system,” says Dr. Alava.

Mother-to-fetus transfer

The researchers were also the first to look at the transfer of pollutants from mother to fetus in one southern resident pair. They found that all the pollutants identified were transferred in the womb, and 95 per cent of 4NP transferred from mother to fetus.

Governments can help protect the southern residents and other marine life by halting production of the chemicals of concern, including 4NP and emerging POPs like 7:3 FTCA, as well as identifying and addressing potential sources of marine pollution in B.C. and Canada.

It's not just the killer whales that are affected, said Dr. Alava. “We are mammals, we eat Pacific salmon as well, so we need to think about how this could affect our health as well as other seafood that we consume.”

This research was supported by funding from the Department of Fisheries, the UBC Student Undergraduate Research Experience and the Nippon Foundation.

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JOURNAL

Environmental Science & Technology

DOI

10.1021/acs.est.2c04126 

ARTICLE TITLE

Emerging contaminants and new POPs (PFAS and HBCDD) in endangered Southern Resident and Bigg’s (Transient) killer whales (Orcinus orca): In utero maternal transfer and pollution management implications

https://libcom.org/article/our-synthetic-environment-murray-bookchin

Our Synthetic Environment - Murray Bookchin - Libcom.org 

Our Synthetic Environment was one of the first books of the modern period in which an author espoused an ecological and environmentalist worldview. It predates ...

Fossils reveal dinosaurs of prehistoric Patagonia

Peer-Reviewed Publication

UNIVERSITY OF TEXAS AT AUSTIN

 

IMAGE: A TIME-AVERAGED ARTIST’S INTERPRETATION OF PATAGONIA DURING THE LATE CRETACEOUS. THE ANIMALS PICTURED INCLUDE NON-AVIAN DINOSAURS, BIRDS AND OTHER VERTEBRATES THAT HAVE BEEN DISCOVERED IN THE FOSSIL RECORD OF THE REGION. THEIR SPECIFIC IDENTIFICATIONS ARE AS FOLLOWS: ORNITHURINE BIRDS (FLYING AND WALKING ON THE GROUND), STEGOUROS (ARMORED DINOSAUR), ORRETHERIUM (MAMMAL), YAMINUECHELYS (TURTLE), A MEGARAPTORID (LARGE CARNIVORE), UNENLAGIINES (PAIR OF CARNIVORES), AND ENANTIORNITHINE BIRDS (IN FOREGROUND) view more 

CREDIT: MAURICIO ALVAREZ AND GABRIEL DIAZ

A study led by The University of Texas at Austin is providing a glimpse into dinosaur and bird diversity in Patagonia during the Late Cretaceous, just before the non-avian dinosaurs went extinct.

The fossils represent the first record of theropods — a dinosaur group that includes both modern birds and their closest non-avian dinosaur relatives — from the Chilean portion of Patagonia. The researchers’ finds include giant megaraptors with large sickle-like claws and birds from the group that also includes today’s modern species.

“The fauna of Patagonia leading up to the mass extinction was really diverse,” said lead author Sarah Davis, who completed this work as part of her doctoral studies with Professor Julia Clarke at the UT Jackson School of Geosciences Department of Geological Sciences. “You’ve got your large theropod carnivores and smaller carnivores as well as these bird groups coexisting alongside other reptiles and small mammals.”

The study was published in the Journal of South American Earth Sciences.

Since 2017, members of the Clarke lab, including graduate and undergraduate students, have joined scientific collaborators from Chile in Patagonia to collect fossils and build a record of ancient life from the region. Over the years, researchers have found abundant plant and animal fossils from before the asteroid strike that killed off the dinosaurs.

The study focuses specifically on theropods, with the fossils dating from 66 to 75 million years ago.

Non-avian theropod dinosaurs were mostly carnivorous, and include the top predators in the food chain. This study shows that in prehistoric Patagonia, these predators included dinosaurs from two groups — megaraptors and unenlagiines.

Reaching over 25 feet long, megaraptors were among the larger theropod dinosaurs in South America during the Late Cretaceous. The unenlagiines — a group with members that ranged from chicken-sized to over 10 feet tall — were probably covered with feathers, just like their close relative the velociraptor. The unenlagiinae fossils described in the study are the southernmost known instance of this dinosaur group.

The bird fossils were also from two groups — enantiornithines and ornithurines. Although now extinct, enantiornithines were the most diverse and abundant birds millions of years ago. These resembled sparrows — but with beaks lined with teeth. The group ornithurae includes all modern birds living today. The ones living in ancient Patagonia may have resembled a goose or duck, though the fossils are too fragmentary to tell for sure.

The researchers identified the theropods from small fossil fragments; the dinosaurs mostly from teeth and toes, the birds from small bone pieces. Davis said that the enamel glinting on the dinosaur teeth helped with spotting them among the rocky terrain.

Some researchers have suggested that the Southern Hemisphere faced less extreme or more gradual climatic changes than the Northern Hemisphere after the asteroid strike. This may have made Patagonia, and other places in the Southern Hemisphere, a refuge for birds and mammals and other life that survived the extinction. Davis said that this study can aid in investigating this theory by building up a record of ancient life before and after the extinction event.

Study co-author Marcelo Leppe, the director of the Antarctic Institute of Chile, said that these past records are key to understanding life as it exists today.

“We still need to know how life made its way in that apocalyptic scenario and gave rise to our southern environments in South America, New Zealand and Australia,” he said. “Here theropods are still present — no longer as dinosaurs as imposing as megaraptorids — but as the diverse array of birds found in the forests, swamps and marshes of Patagonia, and in Antarctica and Australia.”

The research was funded by the National Science Foundation, the National Agency for Research and Development of Chile, and the Jackson School of Geosciences.

The study’s co-authors include Clarke and researchers at the University of Chile, Major University, the University of Concepción and the Chilean National Museum of Natural History.

A figure from the study showing teeth from a megaraptor dinosaur from various view points. The black tooth preserves most of the tooth crow. The tan tooth is missing the crown apex and base.

CREDIT

Davis et al.

The researchers in Patagonia in 2017. Lead author Sarah Davis is in the center of the front row in a blue jacket. The researchers include members from the Jackson School of Geosciences, INACH, the University of Chile, and the University of Concepción.

CREDIT

Sarah Davis

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JOURNAL

Journal of South American Earth Sciences

DOI

10.1016/j.jsames.2022.104163 

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

New records of Theropoda from a Late Cretaceous (Campanian-Maastrichtian) locality in the Magallanes-Austral Basin, Patagonia, and insights into end Cretaceous theropod diversity

Offshore and coastal risk analyses may misrepresent wave storms from extreme weather like bomb cyclones

A new study shows that models used across the globe to estimate the height of coastal storm waves — critical information when building ports, reinforcing infrastructure and estimating flooding — can differ by several feet

Peer-Reviewed Publication

UNIVERSITY OF CENTRAL FLORIDA

A new study shows that models used across the globe to estimate the height of coastal storm waves — critical information when building ports, reinforcing infrastructure and estimating flooding — can differ by several feet.

ORLANDO, Jan. 12, 2023 – Extreme weather events, such as the storm waves generated by the cyclone that recently moved across California, may be underestimated in many models used to estimate coastal flooding, according to a new study led by University of Central Florida researchers.

The study, which was published this week in the journal Science Advances, shows that models used across the globe to estimate the height of coastal storm waves —critical information when building ports, reinforcing infrastructure and estimating flooding — can differ by several feet, leading to some areas being possibly under protected during extreme wave events.

The first-of-its-kind study compared wave estimates from 12 global models with historical buoy observations across different ocean areas.

It found that existing models can reliably represent historical buoy observations across many areas, but no model performs well everywhere and estimates of extreme wave heights can vary between models by up to approximately 20 feet at places.

The study shows that such discrepancies largely exceed current projected 21st changes in coastal extreme wave storm events under a high-emission scenario (9 degrees Fahrenheit in warming by 2100).

“Extreme wave events pose a major risk to offshore-coastal infrastructure and can dramatically affect global coastlines and natural ecosystems through widespread flooding and erosion,” says Joao Morim, a coastal climate researcher in UCF’s Department of Civil, Environmental, and Construction Engineering and the study’s lead author. “Understanding their magnitude and frequency for today’s climate is required for offshore and coastal designs and risk assessments, and it’s essential to assess potential future changes.”

Morim says due to a lack of observations with global coverage, wave models are typically used for many different applications, such as coastal flood risk assessments.

 “We show that depending on the product used, estimated flooding can vary by several feet,” Morim says.

The researchers found that to more accurately assess offshore and coastal risk and inform future mitigation and adaptation responses, decision and policy makers must account for differences between global wave models and take into account observation measurements based on today’s climate.

This means considering different models and using additional, modern observational data to better constrain extreme wave estimates under current climate conditions.

This should be done before considering changes due global warming and sea level rise, which is the main focus of many of the current global and regional flood risk assessments, the researchers say.

The additional data could include long-term observational records from satellite missions and more data from buoys.

“I feel that our results provide a clear message that published broad-scale offshore and coastal risk assessments for present and future climate using extreme wave data taken from specific global and regional wave model products can be misleading and need to consider multiple products to fully assess offshore-coastal impacts and make robust conclusions,” Morim says.

“The results, which are surprising given that current differences between models can differ by several feet, show that we need to consider uncertainties in extreme wave event estimates for today’s climate while also addressing projected future changes due to global climate change,” he says.

For Florida, there are considerable uncertainties concerning wave flooding estimates for the west coast of the state, stemming from the wave models analyzed and the discrepancies between them, which partly result from their different ability in resolving extremes wave storms due to tropical cyclone, the study shows.

“We feel that our research improves our current knowledge and makes a clear point that no uncertainty can be neglected when considering global and regional adaptation,” Morim says.

Study co-authors were Thomas Wahl, an associate professor in UCF’s Department of Civil, Environmental and Construction Engineering; Sean Vitousek with the Pacific Coastal Marine Science Center, U.S. Geological Survey; Sara Santamaria-Aguilar, a postdoctoral researcher in UCF’s Department of Civil, Environmental, and Construction Engineering;  Ian Young with the Department of Infrastructure Engineering, University of Melbourne, Parkville, Victoria; and Mark Hemer with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart, Tasmania, Australia.

The research was funded with support by the UCF Pre-eminent Postdoctoral Program; the NASA Sea Level Change Team; the U.S. National Science Foundation; the U.S. Geological Survey; the Australian Research Council; the Australian Commonwealth National Environmental Science Program and CSIRO’s Climate Science Centre.

Morim received his doctorate in climate change and coastal risk from Griffith University on the Gold Coast, Queensland, Australia. He joined UCF in 2021.

Wahl earned his doctorate in civil engineering from the University of Siegen, Germany, and joined UCF’s Department of Civil, Environmental and Construction Engineering, part of UCF’s College of Engineering and Computer Science, in 2017. He is also a member of UCF’s National Center for Integrated Coastal Research and Sustainable Coastal Systems faculty cluster.

Study title: Understanding uncertainties in contemporary and future extreme wave events for broad-scale impact and adaptation planning

CONTACT: Robert H. Wells, Office of Research, robert.wells@ucf.edu

 

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JOURNAL

Science Advances

DOI

10.1126/sciadv.ade3170 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Understanding uncertainties in contemporary and future extreme wave events for broad-scale impact and adaptation planning

ARTICLE PUBLICATION DATE

11-Jan-2023

Mapping out key sources of emissions for climate change mitigation

Peer-Reviewed Publication

NATIONAL INSTITUTE FOR ENVIRONMENTAL STUDIES

 

IMAGE: REGIONAL FORCING CONTRIBUTIONS IN 2016 UNDER THE HISTORICAL SCENARIO (A-1) AND IN 2100 UNDER THE 1.9 WM-2 (A-2) AND 2.6 WM-2 (A-3) SCENARIOS. PANEL B SHOWS THE FORCING CONTRIBUTIONS IN 2100 RELATIVE TO 2016 LEVELS UNDER THE 1.9 WM-2 (B-1) AND 2.6 WM-2 (B-2) SCENARIOS. THE VALUE ON TOP OF THE BAR INDICATES THE MEAN, AND THE ERROR BAR INDICATES THE ONE-SIGMA UNCERTAINTY OBTAINED FROM THE ENSEMBLE OF EMULATED CLIMATE MODELS. view more 

CREDIT: XUANMING SU

Different regions of the world and different sectors of activity emit various amounts of greenhouse gases and other air pollutants affecting climate change. Knowing the details of these contributions can help policy makers in deciding where to focus their efforts to meet their targets regarding the Paris Agreement. This treaty, signed in 2015, set goals to limit global warming well below 2°C and pursue efforts to limit the increase to 1.5°C above preindustrial levels, to avoid dangerous impacts of climate change. Different regions and sectors (i.e., energy, transportation, agriculture) emit different amounts of greenhouse gases and other air pollutants to the atmosphere. Each of these gases interacts with incoming and outgoing heat (or radiation) in different ways and together determine the amount of warming (or cooling) and climate change we experience. It is therefore important to understand how these interactions with heat or “radiative forcings” might change between regions and sectors over time so we can mitigate climate change effectively.
It is the objective of a team of researchers that conducted a study on how these contributions from different regions of the world, sectors or type of climate forcers may vary. And their study covers both the historical contributions and future scenarios that were developed by research groups around the world, with two low forcing targets of 1.9 W/m-2 (radiative forcing corresponding to a temperature increase of 1.5°C) and 2.6 W/m-2 (2°C). They use a large computational resource to calculate the contributions from different regions, sectors, and climate forcers through a climate model. The authors mention that their analysis is wider than previous studies, adding that no study has yet to assess the contributions from different regions, sectors, and climate forcers at multiple points in the past and the future within a single analytical framework. Their comprehensive attribution assessment shows that achieving these low forcing levels strongly relies on negative CO2 emissions, related to carbon capture and storage methods, under the future scenarios evaluated by them. It also shows that most developing regions and certain sectors, such as housing and transport, can produce larger forcings in 2100 than present even though they are projected to invest substantial efforts to decarbonize. Lastly, it highlights that China, followed by the US, has a crucial role to play in succeeding to bring down the current trajectory to meet these goals.

Regional contributions
Figure 1 from the study puts forward three regions accounting for nearly half of the total radiative forcing, both for the historical and future scenarios: the USA, China and the European Union. While the USA (green) and the European Union (violet) shares are projected to decrease in both low forcing scenarios, China’s contribution is projected to increase, as for many developing regions (India, Middle East and North Africa, Sub-Saharan Africa and Other Asia).

Sectoral contributions
Figure 2 shows that energy and industry would remain the two main sectors contributing to radiative forcings in both low forcing scenarios. In addition, the negative CO2 emissions (grey) would be essential to keep these low forcing levels in 2100, with technologies of carbon capture and storage or BECCS (Bioenergy with carbon capture and storage). As shown by the figure, the major contribution to radiative forcing is CO2 (red). The researchers mention this is related to the life-expectancies of the gases. The scenarios assume that measures to reduce emissions of air pollutants will continue in the coming decades, and the radiative forcings of methane and tropospheric ozone associated with these measures are relatively short-lived (in decades), leaving little impact in 2100. However, CO2 is a long-lived gas, and even though strong emission reductions are assumed in the near term under both scenarios, the abated CO2 emissions will still have a strong footprint on radiative forcing at the end of the century. This highlights the need for putting cutting CO2 emissions as the first priority for long-term climate mitigation. It is interesting to note that the agricultural sector still holds an important share by 2100, reflecting that reducing emissions in this sector (mainly methane and nitrous oxide) would still be a difficult task by the end of the century.

This international study involving research institutes in Japan and France is a comprehensive assessment showing the contribution to radiative forcing by region, sector and climate forcer, both for the historical and future scenarios. It comes as a precious tool to map out how to put efforts efficiently to align on these low forcing scenarios and meet the goals to limit global warming well below 2°C.

Forcing contributions of climate forcers in different sectors in 2016 under the historical scenario (A) and in 2100 under the 1.9 Wm-2 (B) and 2.6 Wm-2 (C) scenarios. The value on top of the bar indicates the mean, and the error bar indicates the one-sigma uncertainty obtained from the ensemble of emulated climate models. Open burning includes agricultural waste burning, forest burning and grass burning. Industry includes industry and solvents. Transport includes the surface transport, aviation and international shipping values.

CREDIT

Xuanming Su

JOURNAL

One Earth

DOI

10.1016/j.oneear.2022.10.009 

METHOD OF RESEARCH

News article

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Identifying crucial emission sources under low forcing scenarios by a comprehensive attribution analysis