Ocean Acidification and Phytoplankton
Water is moved around the globe by the great ocean conveyor belt. As warm surface water is moved away from the tropics, it cools and releases its heat to the atmosphere. The further north this water moves, the cooler and heavier it becomes, eventually sinking to the lower level of the conveyor belt. This cooler water is then carried along the depths of the ocean, picking up nutrients that have gathered there.
As winds move the top layers of the oceans, cold, nutrient rich waters from the depths are brought to the top at “up-welling sites”. These areas are important feeding grounds for phytoplankton — microscopic plants that float in the light filled waters at the top of the ocean. Phytoplankton feed on the nutrients that come from the deep ocean waters and many other species then feed on them. They are the primary producers of the ocean and form the base of many marine food chains.
Scientists predict many ecosystems will be greatly altered or may collapse altogether as a response to global warming. Fresh water is less dense than sea water. Therefore, the addition of significant amounts of fresh water from melting ice caps and glaciers may result in a slowing of the ocean conveyor belt, leading to cooler winters in Western Europe and a disruption of the circulation of vital nutrients to phytoplankton.
Phytoplankton may also be cut off from their food supply as surface temperatures warm, causing the mixing between the warmer top layers and cooler bottom layers to diminish. A decrease in phytoplankton can lead to a collapse of marine food webs, affecting marine mammals (whales, seals and dolphins), sea birds (albatross) and important commercial fish species (cod, salmon and tuna).
Ocean Acidification and Sea Levels
The oceans play an important role in regulating the Earth’s temperature. As the levels of heat and carbon dioxide rise in the atmosphere, so do their levels in the oceans. Rising sea levels are caused by both the warming oceans and melting ice. As water heats above 39.2 F), it expands through a process known as “thermal expansion”. Global warming is causing the oceans to heat up and expand and therefore rise. The melting of glaciers, ice caps, and the Greenland and Antarctic ice sheets are also contributing to the rising seas.
In 2006, the first inhabited island was lost to rising sea levels in the Bay of Bengal. The island of Lohachara sank beneath the surface of of the ocean, and some 10,000 people became the world’s first global warming refugees. This Indian island was situated in an area which has some 70,000 people living on a dozen islands who are all facing the same fate as those of Lohachara. Unlike the area’s human inhabitants, its unique wildlife, including 400 endangered Bengal tigers, are unlikely to survive the rising tides.
Scientists have suggested that by 2080, millions of people are likely to be flooded every year and hundreds of millions more may be displaced by rising seas. Whole island nations could disappear off the map altogether and large swaths of low lying areas are likely to be inundated. Even some of the world’s most important and heavily populated cities, such as New York, London and Bangkok, are at risk of disappearing under the rising waters.
Increasing sea surface temperatures also increases evaporation and the amount of moisture in the atmosphere, which acts as the fuel for thunderstorms. As storms move across the open ocean, they pick up energy from the warm ocean surface and become more powerful. The more heat in the ocean’s surface, the more potential exists for strong winds and heavy rains to be created. It is these winds, rains, and storm surges that can devastate lives and cause billions of dollars of damage.
Hawaiian Birds and ‘Anianiau Breeding
The Hawaiian honeycreeper ‘Anianiau occurs in rugged montane forests from 2000 feet to the highest point of the Hawaiian island. Most common trees in these forests are ‘ohi‘a, koa, ‘olapa, and lapalapa. The ‘Anianiau (Magumma parva) forages mainly on the nectar from flowers of ‘ohi‘a trees, ‘ohelo, and ‘alani. The sides of its brushy-tipped tongue are rolled up to form tube to lap up nectar. It uses its bill to pierce flowers with long corollas (haha‘aiakamanu, ‘ohe naupaka, banana poka) at the base to allow access to nectar. It also captures arthropods by gleaning them from leaves and twigs. Arthropod consumption of caterpillars and spiders probably increases when feeding their young.
Both male and female participate in nest construction which takes 4 to 5 days for the outer shell and 2 to 3 days for the inner lining. It is usually located in the crown of ‘ohi‘a trees, composed of mosses, lichens, ‘ohi‘a leaves and twigs, pukiawe twigs, bark strips, grass and sedge fibers, and rootlets. Median clutch size is 3 eggs. All incubation is done by the female, lasting about 14 days, and the male regularly feeds female off nest during this time.
Like other Hawaiian honeycreepers, males probably begin to sing by spring of first year. Their song is a sweet, high-pitched trill, with individual repeated elements like – weesee-weesee-weesee-weesee or weesity-weesity-weesity-weesity – that drops to a lower pitch two-thirds of the way through song. Simpler trilling songs are given by Kaua‘i ‘Amakihi, ‘Akeke‘e, and ‘Akikiki. ‘Anianiau also have extended, soft vocalizations that are widely referred to as Whisper Song, characterized by short repeated notes with mimicry of other species’ calls and their own songs that may continue for several minutes without pausing. They sing during breeding season from dawn to dusk, most frequently in early morning and late afternoon. Photo by Jack Jeffrey.
Hear the ‘Anianiau produced by SoundsHawaiian
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Hawaiian Reef Fish and Milletseed Butterflyfish
The Milletseed Butterflyfish (Chaetodon miliaris) is endemic to the Hawaiian Islands. Their Hawaiian name is Lauwiliwili, and are friendly, bright yellow fish, growing up to 6 inches. They have vertical rows of dark spots lining the sides of the fish, with a dark bar over the eye region and a dark spot at the base of the tail.
Milletseed Butterflyfish live in aggregations, and it is common to see shoals of these bright yellow fish moving along the reef together, looking for food. Their preferred food is zooplankton, benthic invertebrates, detritus, and fish eggs. Milletseeds sometimes perform as cleaners of other fish, too.
They are especially common near reefs and rocky outcrops to 800 feet. If you dive or snorkel in coral reef environments in Hawaii you are almost certain to encounter these beautiful yellow reef fish.
Hawaiian Birds and Nene Decline
The Nene evolved in a safe, predator-free environment, and their decline began after the Polynesians arrived, bringing to the islands pigs, goats, dogs, and rats, which feasted upon these gentle, trusting, and mostly flightless birds. Later, mongooses were introduced as a means of pest control, and became the scourge of Hawaii, as well as the Nene (Branta sandvicensis).
With the introduction of humans to the islands, the natural balance changed drastically. The habitat was in upheaval due to lowland deforestation, agriculture, and development. Trees were being harvested. Lands were being cleared. Construction of commercial and residential buildings replaced the lush, tropical vegetation. Sugar cane and pineapple crops replaced thousands of acres of native plants, primarily used in the Nene’s diet. Because of the degradation of their ecosystem, nutritional food sources were lacking and led to deficiencies and a higher mortality rate.
The mongoose that had been brought to the Islands to control the rat population, learned to prey upon the nests of the Nene, stealing many of the eggs. The nesting season lasts from August through April, the longest nesting season of any wild goose species, and relatively small numbers of laid eggs survived to the hatching stage. To magnify the problem already facing the young Nene, goslings grow far more slowly than other species of geese, taking them up to three months to fledge, increasing their vulnerability.
In the eighteenth century, the Nene population numbered approximately 25,000 on the Islands of Hawaii, Maui, and Kauai. By 1947 the Nene population had plummeted to only thirty birds. It wasn’t until 1967, that this bird became recognized as an endangered species. Also, the Nene is the only goose endemic to the Hawaiian Archipelago which still exists – at least eight other endemic goose species are known to have become extinct. Today the Nene population has grown to an estimated 1300 living in the wild. The Nene has been saved from being completely wiped out by the implementation of captive breeding and release programs, and 1500-2000 living in captivity. Photo by U.S. Fish and Wildlife Service.
Hawaiian Reef Fish and Bluestripe Butterflyfish
The Bluestripe Butterflyfish, who’s Hawaiian name is Kikakapu, is endemic to the Hawaiian Islands. The Bluestripe Butterflyfish (Chaetodon fremblii) is common among the shallow nearshore reefs to 200 feet from Oahu to Kure Atoll.
It grows up to six inches with bright blue bands running diagonally to obliquely along the fish’s yellow body, which becomes a darker yellow when the fish is alarmed. The fish also has a black spot above and behind the eye, and a black spot at the rear of the fish, extending onto the base of the tail and the dorsal fin.
They are often seen alone feeding on algae, tubeworm tentacles, and other invertebrates. Known as a relic species, the bluestripe butterflyfish has no obvious close relatives (which means that it has likely been in Hawaiian waters a very long time).
