Tag: USGS

Categories
Arctic Change

Seabirds and Sea Ice

MODIS June
MODIS image from June 5; snow and ice have blue/cyan color, while clouds will be lighter gray/white. Image Credit: David Douglass/USGS

Over most of its range the Black Guillemot is a nearshore seabird, occupying coastal waters during both the breeding and nonbreeding seasons, as do other members of the genus Cepphus. Pelagic or open ocean waters can offer abundant prey resources, but these options are often distant, patchy and unpredictable.

The nearshore typically offers seabirds a smaller but more reliable source prey base consisting of forage fish and benthic fauna from the ocean floor such as crustaceans or mussels.

The Arctic Ocean has extensive sea ice cover in the nearshore for the majority of the year; this presents a number of challenges to a nearshore species. Our work on the Cooper Island Black Guillemots has revealed a number of ways in which the species has met these challenges.

The current view from my cabin window illustrates one of the major problems guillemots face in the Arctic. Sea ice extends from the north beach of the island to the horizon and covers Elson Lagoon to the south. The only water available to the guillemots is a brackish pond in the center of the colony that provides no prey but is deep enough to provide sanctuary if the guillemots need to dive when pursued by an owl or falcon — regular visitors to the island.

MODIS July
MODIS image from July 9; snow and ice have blue/cyan color, while clouds will be lighter gray/white. Image Credit: David Douglass/USGS

While guillemots arrived on the island almost a month ago and egg laying is now complete, until recently the closest predictable open water where guillemots could find prey was approximately 20 miles away, off Point Barrow where winds and currents shift the sea ice creating an area of open water. This opening is called a lead. The Cooper Island guillemots stage there in April and May before coming to the island. (Editor’s note: Leads are important for wildlife, because they allow for access to oxygen in the case of seals and walruses and prey in the case of seabirds; you can read more from the National Snow and Ice Data Center here.)

This distance between the Cooper Island guillemots’ nesting colony and access to their prey resources during egg laying and incubation is in sharp contrast to what guillemots breeding in subarctic or temperate waters find at their breeding colonies. These birds occupy waters directly adjacent to colonies well before egg laying and foraging areas may even be within sight of nests. The birds breeding on Cooper Island (and likely all colonies of Mandt’s Black Guillemot Cepphus grylle mandti, the high Arctic subspecies of Black Guillemot) have responded to this spatial disconnect by having a well-defined periodicity in their daily colony attendance. Every day, the parent not incubating eggs and all nonbreeding individuals vacate the colony from approximately noon until midnight. The birds fly individually or in small groups to open water where they can feed for almost half the day before returning to the colony just as the “midnight sun” is at its lowest point in the sky.

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Cooper Island beach with nesting boxes from 2015. Image Credit: George Divoky

While it seems individual birds could fly offshore to open water to feed anytime during the day, there are a number of possible reasons the observed colony-wide pattern of attendance and abandonment developed. For the half of the day when the guillemots are absent – from approximately noon to midnight – there is no evidence that Cooper Island supports a colony of Black Guillemots. It appears to be just a barren sandbar that happens to inexplicably have 200 scattered black plastic cases along with a small cabin surrounded by a bear fence. Falcons, Snowy Owls, and other predators moving along the barrier islands would have little reason to be attracted to this place.

The timing of the birds’ departure and return may be related to changes in air temperature and its effect on ice formation. On nights when the air temperature is below freezing (as it was last night), I have frequently observed the formation of new ice on the surface of the few spaces of open water in the sea ice directly adjacent to shore. This newly formed ice melts in the morning as air temperatures rise. Nocturnal formation of new ice in the waters adjacent to the pack ice reduces the amount of open water available for guillemots to dive for the prey.

This temporary daily reduction in foraging area could be expected to have been pronounced during the Last Glacial Maximum when air temperatures were lower and the ancestors of the Cooper Island guillemots occupied an Arctic refugium. The current pattern of colony attendance for the Cooper Island colony – foraging during the warmest part of the day and attending the breeding colony at night – could have evolved as a way of maximizing the amount of open water available for guillemots.

The large expanse of shorefast ice north of the island this year is persisting later than expected compared to recent years. While the nearshore ice may now be forcing the Cooper Island guillemots to fly further in search of prey, it could benefit the colony later this summer should ice remain in the nearshore close to the colony. In recent years a lack of sea ice when the guillemots are feeding young resulted in increased nestling mortality as higher sea surface temperatures reduced the availability of Arctic Cod, the guillemots’ preferred prey.

Should this year’s nearshore ice break up slowly over the next month, Arctic Cod could remain in the guillemots’ foraging range and allow increased chick growth and fledging success. The latter is urgently needed for the colony to reduce its current population decline. First eggs will be hatching in about two weeks and our daily weighing of nestlings and prey observations should demonstrate how much this year’s persistent sea ice has affected the guillemots’ nearshore environment.

This field report is part of an ongoing series titled Arctic Change centered around George Divoky’s 44th field season studying Black Guillemots, sea ice, and climate change on a remote Arctic island off the coast of Alaska. To donate and support Divoky’s work on Cooper Island, visit the Friends of Cooper Island website.

Read more

Arctic Sea Ice a Major Determinant in Mandt’s Black Guillemot Movement and Distribution During Non-Breeding Season by G. J. Divoky, D. C. Douglas, I. J. Stenhouse

All About Sea Ice by National Snow and Ice Data Center

Summertime and the Sea Ice is Leaving by Jenny Woodman

Take the A-Train to the Arctic by Jenny Woodman

 

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Categories
Exploring Ocean Worlds Sea Sentries

The Uncommon Common Murre

Common Murres on Farallon Islands. Image Credit: Point Blue Conservation Science

 

 

Common Murres in flight, some with fish. Image Credit: Julie Chase/ACCESS/NOAA/Point Blue

Common Murre are abundant here; many can be seen carrying fish on a return flight to the Farallon Islands, where hungry babies eagerly wait for their next meal. The islands — uninhabited by humans except for a small group of scientists — are nesting grounds for thirteen species of seabirds and six species of marine mammals that breed or haul out on the islands each year.

According to U.S. Fish & Wildlife service, the Farallons host the largest seabird nesting colony south of Alaska with numbers greater than 350,000 in the summer, including nesting Common Murres, Tufted Puffins, Pigeon Guillemots, and Western Gulls.

Just 27 miles west of San Francisco, these rocky islands weren’t always an ideal habitat for seabirds. During the California Gold Rush, a lack of agricultural infrastructure led hungry prospectors and entrepreneurial foragers to the Farallons for eggs, which pushed the Common Murre to the brink of extinction.

Over the years, a combination of exploitation from hunting and foraging to military uses left the island in a state of disarray. Feral cats and nonnative rabbits introduced by previous inhabitants obliterated many seabirds. Oil spills and pollution also took a toll on the habitat, which was established as a national wildlife refuge in 1909 by Theodore Roosevelt. Since the late 1960s, partnerships between U.S. Fish & Wildlife, NOAA, and Point Blue Conservation Science have helped to restore and maintain the Farallons for wildlife and research.

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Computer imagery shows the topography of the seafloor of Greater Farallones National Marine Sanctuary and the steep drop-off of the continental slope west of the Farallon Islands. Image Credit: USGS/Woods Hole

We’re here on the second day of an Applied California Current Ecosystem Studies, or ACCESS, cruise. It is part of a long-term effort, now in its 15th year, to monitor and understand the oceanographic conditions, prey availability, and abundance and distribution of seabirds and whales in the region.

The data collected on these cruises, which take place three to five times per year, are used to help inform decision-making and research priorities in Northern and Central California National Marine Sanctuaries. ACCESS is a partnership between NOAA National Marine Sanctuaries and Point Blue Conservation Science.

Seabirds and marine mammals are drawn to the region by a process called upwelling. In the spring, strong winds move across the surface of the ocean circulating and drawing cold, nutrient-rich water from the deep ocean areas that lie below the edge of the Continental Shelf and Slope. This process is part of what makes these waters, according to NASA, “some of the most biologically productive in the world.”

When these nutrients reach the sunlight at the surface, the perfect environment is created for marine plant life — from phytoplankton to kelp forests. The plants, in turn, feed the wildlife.

Krill thrive in these nutrient-rich waters. “Its size is tiny, but its significance is colossal,” Mary Jane Schramm writes. “Krill – a shrimp-like crustacean – forms the basis of the marine food web for whales, seabirds, fish, squid, seals, and sharks throughout the world’s oceans.”

As we zigzag along the coast via predetermined transect lines, this productivity is evident in both the variety and quantity of life seen here.

The expert wildlife observers are armed with details to make each sighting even more exciting. When prompted, Dru Devlin, research associate for Greater Farallones Association, offers up a litany of fascinating details about the Common Murres, which nest on steep, rocky cliffs.

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Common Murres on Farallon Islands. Image Credit: Point Blue Conservation Science

The female lays one large blue egg, which she sits on for the duration without nourishment. When the egg finally hatches, she takes off to replenish her strength for whatever lies ahead and the father steps in to take care of the baby chick. (In Far from Land: The Mysterious Life of Seabirds, Michael Brooke points out that seabirds generally only produce one to two eggs per year, which he adds is smart evolutionary strategy, because otherwise the ocean would be full of birds with nothing to eat!)

Murre chicks leave the nest, before they’ve fledged, meaning they haven’t grown flight feathers. When the time comes, the father and chick leap off the steep cliff and into the water below where the little one floats for up to two months, waiting for its flight feathers to come in.

Yesterday, we heard a cacophony of bird calls throughout the day; Devlin explained that we were hearing the father birds calling out to their chicks as they returned from fishing for food. Devlin concludes her explanation by asking me to imagine what it must be like to look for your baby in the midst of rough seas and large swells and I find myself, once again, awestruck by the tenacity of seabirds.

 

 

Black-footed albatross in flight. Image Credit: Julie Chase/ACCESS/NOAA/Point Blue
Pacific White-Sided Dolphins. Image Credit: Jenny Woodman/ACCESS/NOAA/Point Blue

In a very short period of time, I’ve seen so much. As a city kid from Philadelphia, my encounters with animals outside of zoos were limited to squirrels and pigeons, so much of these sightings are pretty big firsts for me. While everyone was busy deploying equipment on a side deck after breakfast, I ducked around a corner for a quiet moment and found myself alone with a pod of Pacific white-sided dolphins, playfully lingering alongside our vessel.

Observing these creatures is a rare treat made even better when accompanied by a team of biologists and wildlife experts to explain what I see and fill me with a sense of wonder for new favorites like the uncommon Common Murres.

Spotted Wednesday, July 4:

Common Murres

Sooty Shearwaters

Sabine’s Gulls

Herring Gulls

Brown Pelicans

Cassin’s Auklets

Blue Whales

Humpback Whales

Unidentified Whales

California Sea Lions

Jenny Woodman, Proteus founder and executive director, is a science writer and educator living in the Pacific Northwest. Follower her on Twitter @JennyWoodman.

This article was updated on July 5.

Read more

History of Farallon Islands by U.S. Fish & Wildlife Service

Farallon National Wildlife Refuge by U.S. Fish & Wildlife Service

California Coastal Current by NASA Earth Observatory

The Farallon Islands are Off Limits to Humans – but Not Wildlife by Bonnie Tsui

Common Murre Identification by Cornell Lab of Ornithology

Tiny Krill: Giants in the Marine Food Chain by Mary Jane Schramm for NOAA National Marine Sanctuaries

Categories
Arctic Change

Take the A-Train to the Arctic

This Aqua satellite was launched in 2004; it collects about 89 Gigabytes of data per day about elements of the Earth’s water cycle -- including water in liquid, solid, and vapor form. Image Credit: NASA’s Earth Observing System
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This Aqua satellite was launched in 2004; it collects about 89 Gigabytes of data per day about elements of the Earth’s water cycle — including water in liquid, solid, and vapor form. Image Credit: NASA’s Earth Observing System

In the Arctic, much depends on ice. Pack ice. Drift ice. Old ice. New ice. For some wildlife, ice provides safe haven from predators and for others, it offers access to prey. For humans, many of whom are living in isolated coastal communities with no roads in or out, ice is everything.

Sailors and explorers have kept sporadic records about ice conditions dating back thousands of years, but only since 1979, with the launch of Earth observing satellites, have streams of near-constant information about Arctic sea ice been available. Using images and observations captured daily, scientists are able to measure ice thickness, area of coverage, and seasonal fluctuations in the advance and retreat of ice coverage.

Real-time sea ice images and data are vital for the safety of researchers like George Divoky and for people in Arctic communities who depend on ice for subsistence hunting and fishing. Anthony Fischbach is a wildlife biologist for the United States Geological Survey (USGS) in the Alaska Science Center Walrus Research Program, where he has worked since 1994. Fishbach delivers a daily “Ice Mail” to just over 100 people interested in up-to-date information on Arctic sea ice. Subscribers include Divoky, scientists in Russia, and remote Inuit communities who may not have easy access to internet connections capable of retrieving large amounts of data.

“The main niche I’m trying to fill is a way to get meaningful sea ice imagery and charts in the palm of your hand or on the deck of a ship where you’ve got really minimal bandwidth,” said Fischbach. “If you’re in a remote community that has 2G cell phone connection or if you’re on an Iridium-linked vessel, the existing ways of accessing the data just don’t meet the need.”

He described his own experiences of working in Arctic coastal communities or being on board a retrofitted crabber, “We just struggled to get the data through the existing methods and we couldn’t get all the data we wanted.”

Today, Fischbach relies heavily on two satellites we’ll be following closely this summer — Aqua and Terra. Both are part of NASA’s Afternoon Constellation or A-Train, which is a convoy of satellites operated by NASA and international partners. The satellites travel together, completing a polar orbit twice a day; because of the Earth’s rotation, a polar orbit means that the satellites will observe the entirety of the planet’s surface every one to two days.

The A-Train crosses the equator at about 1:30 a.m and 1:30 p.m.; the Terra satellite passes the equator in the early morning, Aqua in the afternoon. This timing and repetition allows scientists to generate cloud-free images and to study how temperatures over land and water change from day to day.

By flying satellites loaded with a host of Earth-observing instruments in a formation, scientists are able to gather a great deal of meaningful data. According to NASA, flying in concert “allows for synergy between the missions—synergy means that more information about the condition of the Earth is obtained from the combined observations than would be possible from the sum of the observations taken independently.”

While each satellite is tasked with different mission objectives, the data from individual instruments can be combined to paint a more vivid and informative picture of the Earth’s climate and atmospheric systems.

This visualization shows the orbits of NASA-related near-Earth science missions that are considered operational as of March 2017. Video Credit: Greg Shirah for NASA Visualization Studio

A key instrument on board Aqua and Terra is a moderate resolution imaging spectroradiometer, or MODIS for short, which is capable of of observing across 36 spectral bands or wavelengths at different resolutions (250, 500, and 1000 meters). (A complete technical profile of this instrument and the data it provides can be found here.)

MODIS is an integral instrument for studying the ocean, because it aids in the creation of ocean color maps. Ocean color reveals much about phytoplankton productivity, which, according to NASA, forms the basis of the ocean’s food chain and plays a big part in carbon storage and movement. MODIS also allows for detailed maps of sea surface temperatures, which are known to influence weather patterns. Since MODIS is able to study water in liquid, solid or gas form, the instrument aids measurement of snow and sea ice and how much solar energy is being absorbed or reflected back to space.

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This ice map for May 24, 2018, generated by United States Geological Survey (USGS) in Alaska, combines MODIS images from Aqua and Terra with National Ice Center data. Image Credit: Anthony Fischbach for USGS

Fischbach explains that the images in his daily emails (seen above) are processed with false color so you can distinguish the white of the clouds with the white of the sea ice; sea ice is aqua-colored and the clouds appear white. The images show detail down to 250 meter resolution, meaning you can clearly see objects that are 250 meters or 820 feet wide.

To people living and working in the the Arctic, these sea ice data could be comparable to monitoring hazards on roadways in the lower 48, because the ice and water provide access for both transportation and food.

The ice is moving constantly, which creates precarious decision-making choices in remote regions without the right information. With several days of ice data in hand, people in the field  like Fishbach and Divoky can make better choices.

“I’d really like to know as much as I can about how the ice is moving. Is there more ice coming this way? Is it going to be congesting? Is it going to be opening up?” he asks. “You know, do I launch boat out in to the ice —  the shifting seascape — where I could get pinned in and trapped and not make it home?”

This story is part of an ongoing series titled Arctic Change centered around George Divoky’s 44th field season studying Black Guillemots, sea ice, and climate change on a remote Arctic island off the coast of Alaska. To donate and support Divoky’s work on Cooper Island, visit the Friends of Cooper Island.

Read More

Arctic Sea Ice By NASA Earth Observatory

50 Years of Earth Observation by European Space Agency

Monitoring Sea Ice by NASA Earth Observatory