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AOML’s Coral Health and Monitoring Program (CHAMP) rolled out a new data source in October as part of its online data query tool. Optimally Interpolated Sea Surface Temperatures, or OISSTs, are data from microwave satellite observation platforms, products that are sourced from Remote Sensing Systems. Whereas other sea surface temperature sources might be missing data due to orbital gaps or non-ideal environmental conditions such as cloud cover or rainfall, the OISST platform corrects for these errors to provide a complete, daily sea surface temperature map that can benefit coral health and monitoring efforts worldwide.

Members of AOML’s Acidification, Climate, and Coral Reef Ecosystems Team (ACCRETE) recently traveled to two remote reef locations to expand the National Coral Reef Monitoring Program’s (NCRMP) network of sentinel climate and ocean acidification monitoring sites. The newly established sites, located in the Flower Garden Banks and the Dry Tortugas, will provide researchers with additional data and insights into the ocean’s changing chemistry and the progression of ocean acidification, as well as the ecological impacts of these variables across the Caribbean basin and the Gulf of Mexico.

This summer, AOML will be diving into a new outreach initiative with the Central Caribbean Marine Institute, a coral reef research organization based in the Cayman Islands. From June through August, NOAA oceanographers from AOML will give a series of talks on various oceanographic topics to the institute’s staff and students participating in the National Science Foundation’s (NSF) Research Experiences for Undergraduates program at the institute’s Little Cayman Research Centre (LCRC).

Central Caribbean Marine Institute is a non-profit organization whose mission is to conduct and facilitate research, education, outreach and conservation programs that will sustain marine diversity. They support key research into addressing global issues such as climate change, marine protection, fisheries management and coral reef impacts. Every summer, the institute hosts undergraduate students at the LCRC as part of the NSF funded research program. Students work with mentors to design, implement, and present research projects within the institute’s research themes of coral reef stress, climate change, ocean acidification, and coral reef resilience and restoration.

This lecture series provides students with an opportunity to gain insight into current coral reef research programs in order to help them refine their summer projects. The series also offers networking opportunities for students and staff and fosters relationships with the AOML research community. Topics will range from ocean-reef interactions, microbiology, ecosystem-based management, and impacts to coral health. Funding for the lecture series is being provided by CCMI.

“I always get bored with minute-detail subjects like molecular studies, but Dr. Chris Kelble’s lecture on the science to inform ecosystem-based management was all about the bigger picture. It’s a topic that I would love to get into,” said Brian Griffiths, an REU student from the University of Delaware. “Dr. Kelble was the first scientist I’ve encountered so far that thinks like I do. He was a great role model to have met!”

In addition to providing lectures, NOAA oceanographers will be teaming up with CCMI scientists and the National Centers for Environmental Information to examine variations of temperature and light at the local scale over the coral reefs surrounding Little Cayman Island. Collecting and analyzing this important data will enhance NOAA’s coral reef ecological forecasting tools and help evaluate the adequacy of regional-scale observations in monitoring for environmental threats to the reefs. This data will also assist other research projects being carried out by various research groups on the Little Cayman reefs including projects focused on constructing a global climate record using coral core samples, connecting water conditions to algal growth on the reefs, and investigating why some reefs are more resilient than others over small distances.

Located on Little Cayman Island, the LCRC is situated next to some of the most biologically diverse reef systems on earth. These reefs are particularly important to coral reef scientists as they are largely unaffected by local human and development impacts. This isn’t the first time NOAA oceanographers will collaborate with the Little Cayman-based research center. NOAA’s Coral Reef Early Warning System (CREWS) established a monitoring station on the reef adjacent to the research center in 2009. CREWS stations are scattered across the Caribbean and contain a suite of oceanographic and atmospheric sensors that monitor environmental conditions in an effort to provide scientists with early warning of climate-related events such as coral bleaching.

See below for a complete schedule of the lecture series:

June 23 – 29

– “Synergistic Effects of Eutrophication and Elevated SST in the Early Life Stages of Two Caribbean Corals”

July 30 – August 3

– “Molecular Microbiology in the Marine Environment:  Biocomplexity, Microbial Source Tracking, and Metagenomic Observations”

– “Interactions Between Ocean Health and Human Health”

– “Coral Research at NOAA/AOML’s Ocean Chemistry and Ecosystems Division”

– “Supporting NOAA Coral Reef Research:  the Cooperative Institute for Marine and Atmospheric Studies”

August 3 – August 7

– “Spatial Gradients in Carbonate Chemistry and Their Influence on Ecosystem Processes”

– “Science to Inform Ecosystem-Based Management”

– “Sloshing and Mixing Between Reef and Ocean: Physical Processes Impacting Connectivity and Thermal and Biogeochemical Variability for Cayman Corals”

Photograph of bleached pillar coral on November 13, 2014 at Sand Key. Image credit: NOAA’s Florida Keys National Marine Sanctuary.

2014 was a relatively warm summer in South Florida, and local divers noticed the effects of this sustained weather pattern. Below the ocean surface, corals were bleaching. In the month of August, the Coral Bleaching Early Warning Network, jointly supported by Mote Marine Lab and NOAA’s Florida Keys National Marine Sanctuary, received 34 reports describing paling or partial bleaching and an additional 19 reports indicating significant bleaching. Scientists continue to monitor the impact of this severe bleaching event to determine the extent of coral mortality.

This image, taken on November 13, 2014 by the Florida Keys National Marine Sanctuary, shows a severely bleached pillar coral at Sand Key in the Florida Keys. Images like this one indicate that some regions and species will definitely be affected. Pillar coral is one of the species of coral listed as threatened under the Endangered Species Act.

AOML Coral Ecologists Derek Manzello and Jim Hendee provide insight as to how the environmental conditions they are tracking indicate that a mass bleaching event is possible and even likely in the Florida Keys.

What is coral bleaching?

Coral colonies are made up of hundreds or even thousands of genetically identical individuals called polyps. These polyps have microscopic colorful algae called zooxanthellae living within their tissues. The zooxanthellae work like an internal symbiotic vegetable garden, carrying out photosynthesis and providing energy to their coral hosts, which helps reef-building corals create reef structures. When a coral bleaches, it expels its zooxanthellae, and can die within a matter of weeks unless the zooxanthellae populations are able to recover. The term bleaching is used because the dazzling colors of living corals are due to the zooxanthellae in coral tissue, and when zooxanthellae are lost, corals appear white, or “bleached.”

Extensive bleaching of the soft coral Palythoa caribaeorum on Emerald Reef, Key Biscayne, Fl. (Credit:NOAA)

What causes coral bleaching?

It is well established that elevated sea temperatures cause widespread coral bleaching. Warmer waters “stress” corals and trigger coral bleaching.

There are two types of heat stress that can trigger bleaching:  (1) short-term, acute temperature stress (several days of very high water temperatures) and, (2) cumulative temperature stress (weeks of consistent moderately elevated water temperatures). Scientists have documented that coral communities around the world have different heat stress thresholds that typically trigger bleaching in response to heat stress. Scientists rely on long-term observing stations co-located with coral reefs to identify the specific conditions that correlate to bleaching within different regions.

What specifically triggers bleaching of coral found in the FL Keys?

Using long-term in situ datasets such as the Coastal-Marine Automated Network, or C-MAN, stations in the Florida Keys, AOML scientists identified specific patterns of warm waters on coral reefs that tend to precede bleaching

events.  The indices that proved to be the most reliable indicators for bleaching for the Florida Reef Tract are maximum monthly sea surface temperature and the number of days >30.5 C (86.9 F).

What patterns have scientists noticed leading up to this most recent bleaching event?

Data from the Molasses Reef C-MAN station showed that the winter of 2014 was the warmest on record since these stations began recording data in 1988.  The second warmest winter on record was the winter of 1996/97, which preceded back-to-back bleaching years in the Keys (1997/98) and was the worst bleaching event ever documented in the Florida Keys.  The most recent significant bleaching event in the Florida Keys occurred in 2005, and there have been mild localized bleaching events since then.

The images above were taken from a coral colony at Cheeca Rocks in the Florida Keys. On the left shows the coral colony from July 2013. The image at the right shows the same coral colony in August 2014, with the colony now bleached. (Credit: NOAA)

The warm winter and warm water temperatures this spring caused scientists to start watching the long-term average water temperatures at these stations to see if the average daily temp was regularly reaching or exceeding 30.4 C, the trigger point for previous bleaching in the FL Keys. The Molasses Reef C-MAN site quickly approached this temperature threshold in July and August. Average temperatures were also warmer than normal at the Fowey Rocks C-MAN station and the Cheeca Rocks Atlantic Ocean Acidification Testbed in the northern Keys. With water temperatures now exceeding this threshold for more than thirty days, and reports of bleaching beginning to pour in, there are concerns about widespread bleaching throughout the region.  To assess the extent of the bleaching event, Florida Keys National Marine Sanctuary has been working with its partners to monitor the current state of corals along the reef tract.

Jim Hendee is the acting division director of AOML’s Ocean Chemistry and Ecosystems Division. Jim leads the coral group at AOML and studies the environmental conditions that cause ecosystem-wide changes on coral reefs using in situ observing stations. Derek Manzello is a coral ecologist at AOML and leads research of the impacts of ocean acidification on coral reefs. Derek also studies the impact of other changes in environmental conditions on reefs such as temperature and tropical storm impacts.

Originally Published September 2014 by Shannon Jones

Ian Enochs, a scientist with NOAA’s Cooperative Institute for Marine and Atmospheric Studies at the University of Miami, traveled in May to the Island of Maug in the Pacific Ocean as part of a NOAA expedition aboard NOAA Ship Hi’ialakai to study coral reef ecosystems. The expedition was led by NOAA’s Pacific Island Fisheries Science Center Coral Reef Ecosystem Division and the Pacific Marine Environmental Lab’s Earth-Ocean Interaction group. Enochs focused his research on underwater vents that seep carbon dioxide into the Pacific.

Why journey to the Island of Maug to study ocean acidification?

Maug is a unique natural laboratory that allows us to study how ocean acidificationaffects coral reef ecosystems. We know of no other area like this in U.S. waters. Increasing carbon dioxide in seawater is a global issue because it makes it harder for animals like corals to build skeletons.

What is the Island of Maug like?

Maug is an uninhabited volcanic island in the Commonwealth of the Northern Mariana Islands about 450 miles north of Guam. The volcano breaks through the ocean surface in three areas to form islands and the relatively shallow water surrounding these islands is full of coral reefs. The underwater vents that seep carbon dioxide are found on the side of the caldera or crater formed by the volcano. Usually when I scuba dive, the moment I enter the water, air bubbles surround me and fade away quickly. On Maug, the bubbles never ceased and it felt like I was swimming in a glass of champagne.

A funel is used to collect carbon dioxide gas bubbles from the seeps near the coral reefs. Photo credit: Open Boat Films/NOAA

What are your goals for studying the carbon dioxide vents?

We’re mapping carbonate chemistry over time and space to examine the extent of carbon dioxide at the site. We’re looking at how that chemistry changes over this area as you get farther from the vents and what corresponding changes there are in the coral community. We hope to learn more about which coral species are especially sensitive to elevated carbon dioxide and which may be resilient. Finally, we will look at how elevated carbon dioxide levels in seawater may influence the response of various organisms over time, including their growth rate.

What does your sampling show so far?

The carbon dioxide appears to be strongly influencing the growth of corals and algae in a small area around the vents. While there is weedy algae near the vent due to high levels of carbon dioxide, this gives way to healthier coral reefs as you get farther away from the site.

How do you measure these effects over time?

This first trip has allowed us to begin measuring the effects of carbon dioxide and to place instruments in the area that will continuously measure temperature, light, the partial pressure of carbon dioxide, seawater pH, and water currents. When we return in August, we’ll have three months of data on how this special environment has been changing day to day. Additionally, we are able to measure coral growth over time by taking core samples and by using a special dye to measure new growth.

How can this research help our understanding of this and other areas of the ocean?

Research at the Maug site will help us determine the effects of elevated carbon dioxide on an entire natural ecosystem. Using this information, we’ll have a better understanding of how the rest of the ocean’s coral reefs may react to global increases in carbon dioxide and acidification. If the predictions of the Intergovernmental Panel on Climate Change remain the same, by the end of the century, the impact of ocean acidification on coral reefs around the world will be comparable to what we see on the reefs near Maug’s carbon dioxide seeps today.

Note: Ian Enochs’ research is part of a much larger research mission involving NOAA Fisheries, NOAA’s Coral Program, NOAA Research’s Pacific Marine Environmental Lab, the National Institute of Standards and Technology and other partners, including Scripps Institution of Oceanography, the University of Guam, and Open Boat Films. NOAA worked closely with CNMI coral management and monitoring experts at the Division of Coastal Resource Management and the Department of Environmental Quality. More information on the research mission is posted online.

While tropical cyclones can dramatically impact coral reefs, a recent study reveals their passage also exacerbates ocean acidification, rendering reef structures even more vulnerable to damage. Calcifying marine organisms such as corals that thrive in alkaline-rich waters are increasingly imperiled as seawater becomes more acidic due to the ocean’s uptake of carbon dioxide. The detrimental effects upon these organisms have been documented, but less is known about how reefs might react to ocean acidification when coupled with an additional stress factor such as a tropical cyclone.

To assess how reefs might respond to such a scenario, coral researchers Derek Manzello, Ian Enochs, and Renee Carlton from the Cooperative Institute for Marine and Atmospheric Studies at the University of Miami’s Rosenstiel School and NOAA’s Atlantic Oceanographic and Meteorological Laboratory, along with researchers from the University of Washington and NOAA’s Ocean Acidification Program, collected data from reefs in the Florida Keys before, during, and after the passage of Tropical Storm Isaac in August-September 2012. Their findings appear online in the Journal of Geophysical ­Research.

Tropical Storm Isaac as it passes over the Florida Keys on August 26, 2012. Image Credit: NOAA

The team analyzed seawater carbonate chemistry and environmental data from Cheeca Rocks and Little Conch Reef, both coral monitoring sites, as well as data from a coastal marine automated network station at Molasses Reef.

They found that Tropical Storm Isaac caused both an immediate and prolonged decline in seawater pH and carbonate saturation state at the two coral reef sites studied. The post-storm pH levels were the lowest recorded values to date from over two years of high-resolution data measured at the Cheeca Rocks ocean acidification monitoring site, and this depression in pH lingered for more than a full week.

Prior concerns regarding ocean acidification and coral reefs assumed carbonate undersaturation would not occur at reefs in the foreseeable future due to their location within the highly supersaturated tropical oceans. However, the study demonstrates that carbonate undersaturation at reefs will occur from even the passage of a modest tropical storm when coupled with ocean acidification.

Coral bleaching at Cheeca Rocks in the Florida Keys. Image credit: NOAA

With climate models projecting a steady increase in the rate of ocean acidification, along with stronger, more frequent tropical cyclones, the future for coral reefs thus appears bleak. In the coming decades, tropical cyclones could depress carbonate seawater saturation ­levels to such an extent that reefs will undergo periods of post-storm dissolution, weakening coral reef frameworks and worsening the widespread ecological and economic consequences of the coral reef crisis.