Hydrography and geostrophy around Easter Island

Moraga, Julio; Valle‐Levinson, Arnoldo; Olivares, Jorge

doi:10.1016/s0967-0637(98)00083-1

Cited by 14 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Silica has usually been observed to be higher than nitrate, shows little fluctuation in surface gyre waters, and has been suggested not to be a limiting nutrient (discussed above), so silica would not be expected to explain these changes. Also, the lowest silica concentrations reported (<0.8 µmol L -1 ) are near Easter Island (Moraga et al, 1999), possibly indicating consumption by diatoms. Dinoflagellates showed no similar patterns in composition (Fig.…”

Section: Analysis Of a Possible Island-mass Effect Around Easter Islamentioning

confidence: 93%

Biological oceanography, biogeochemical cycles, and pelagic ecosystem functioning of the east central South Pacific Gyre: focus on Easter Island and Salas y Gomez Island

Dassow

Collado-Fabbri

2014

lajar

View full text Add to dashboard Cite

ABSTRACT. The Exclusive Economic Zone of Chile defined by Easter Island and Salas y GómezIsland is in the South Pacific Sub-tropical Gyre (SPSG), putting it at the center of the most oligotrophic and biomass poor waters in the world. Only 10 biological oceanographic expeditions have entered this zone in 105 years . We review key aspects of the plankton ecosystem and biogeochemical function relevant for the understanding of and conservation planning for marine environments. Plankton production is limited by lack of dissolved inorganic fixed nitrogen, not phosphorous. Higher organic nitrogen levels might be biologically unavailable. Short-term experiments suggested iron is not limiting, yet iron still likely limits nitrogen fixation, and thus production, at longer time scales, as the presence of nitrogen-fixers is exceptionally low compared to other ocean gyres. Plankton function is dominated by the smallest unicellular organisms, picoplankton (<3 µm in diameter). The SPSG represents a center of high biodiversity for picoplankton, as well as heterotrophic organisms such as tinntinids, siphonophores, and possibly amphipods, although data for key zooplankton, such as copepods, are lacking. Many groups exhibit negative relationships between diversity and total plankton biomass. High diversity might result from dispersal from a very large metacommunity and minimal competition within functional groups. Whether an island-mass effect causes a real or apparent increase in plankton biomass around Easter Island must be confirmed by high-resolution sampling in situ. Long-term threats to the planktonic ecosystem may include climate change-enhanced ocean stratification and plastic marine debris accumulation. Finally, priorities for future research are highlighted.

show abstract

Section: Analysis Of a Possible Island-mass Effect Around Easter Islamentioning

confidence: 93%

Biological oceanography, biogeochemical cycles, and pelagic ecosystem functioning of the east central South Pacific Gyre: focus on Easter Island and Salas y Gomez Island

Dassow

Collado-Fabbri

2014

lajar

View full text Add to dashboard Cite

show abstract

“…The island hosts a diverse algal population (Santelices and Abbott, 1988), but its primary production is limited by low nutrient levels in the water typical of the mid-Southeast Pacific gyre in which it is situated (Moraga et al, 1999). The island's leafy algal species, primarily Sargassum skottsbergi and Zonaria stipitata, are unpalatable for most fishes and invertebrates as indirectly suggested by our personal observations, data reported below, and Duhart and Ojeda (1994).…”

Section: Introductionmentioning

confidence: 76%

“…Since our survey publication (DiSalvo et al, 1988), new data have become available on oceanographic characteristics of the sea around Easter Island, including nutrients, temperature and currents (Moraga et al, 1999). Other studies have added knowledge of faunal groups of the island such as the sponges (Desqueyroux-Faundez, 1990), corals (Glynn et al, 2003), molluscs (Raines, 2002) and macrocrustaceans (Poupin, 2003) as well as certain less conspicuous groups including the Foraminifera (Zapata and Olivares 2000), the Ostracoda (Whatley et al, 2000) and the Isopoda (Kensley, 2003).…”

Section: Introductionmentioning

confidence: 99%

Stomach contents and feeding observations of some Easter Island fishes

DiSalvo¹,

Randall²,

Cea³

2007

Atoll Research Bulletin

View full text Add to dashboard Cite

Stomach contents of 42 species in 25 familes of Easter Island shore fishes were examined in comparative terms to determine prey items and feeding behavior at this isolated island outpost in the southeastern Pacific. The island's impoverished marine fauna and flora have resulted in considerable dietary overlap among the inshore fishes. Some endemic species appear to feed mainly on endemic invertebrates. Some prey species which were found in the fish stomachs, such as the stomatopod Odontodactylus hawaiiensis, the pandalid shrimp Plesionika edwardsi, and several tiny molluscs were previously unrecorded for the island.

show abstract

“…Winds blow throughout the year and are predominantly from east−southeast, but the influence of strong easterlies on the ocean surface can be felt even on the leeward northwest coast as energy is refracted and diffracted around the tips of the island. Unfortunately, local nearshore circulation patterns around the island are unknown, although surface circulation in the region is generally east to west (Glynn et al 2007), and the island itself does modify the predominantly northwestern large-scale geostrophic flows (Moraga et al 1999). Like most sites along the western and northern coasts where coral communities are particularly well developed, Tautara is characterized by overall high coral cover (80%), with Pocillopora verrucosa and Porites lobata contributing similarly to total coral abundance (see Wieters et al 2014 for quantitative description of temporal and geographic patterns in functional structure and coral abundances around the island).…”

Section: Study Sitementioning

confidence: 99%

Patterns in sexual reproduction of the dominant scleractinian corals at Rapa Nui (Easter Island): Pocillopora verrucosa and Porites lobata

Buck-Wiese¹,

Burgués²,

Medrano³

et al. 2018

Aquat. Biol.

View full text Add to dashboard Cite

Sexual reproduction is fundamental to the maintenance and recovery of coraldominated communities in high-latitude and isolated locations, where replenishment often depends on local reproductive activity rather than recruitment from distant reefs. Rapa Nui (Easter Island) is one of the most remote islands in the Pacific, lying at the southern, subtropical edge of the range of reef-building scleractinians. Here, we describe the sexual reproduction and timing of the 2 dominant corals, Pocillopora verrucosa and Porites lobata. Reproductive activity was inferred from the identification and staging of gametes via histological analyses of monthly samples collected from December 2012 to May 2014 at 12 m depth at Motu Tautara (27°6.6' S, 109°25.5' W) with in situ temperature records. In P. verrucosa, the observed hermaphroditic activity spanned from December to January, resulting in mature oocytes of 117 µm mean diameter. In P. lobata, observed gonochoric activity spanned from December to March, resulting in mature oocytes of 180 µm mean diameter. The observed initiation of gametogenic cycles coincided with the onset of spring warming in both species. Inferred spawning of P. verrucosa followed a relatively calm period of daily variance reduction in local in situ temperature and wind speed prior to the peak in thermal conditions, whereas inferred spawning of P. lobata coincided with peak temperatures in one year but not the other. We suggest temporal restrictions of disruptive coastal activities such as dredging during coral spawning periods and mitigation of land-based sources of pollution and watershed discharge that may reduce water quality.

show abstract

Hydrography and geostrophy around Easter Island

Cited by 14 publications

References 0 publications

Biological oceanography, biogeochemical cycles, and pelagic ecosystem functioning of the east central South Pacific Gyre: focus on Easter Island and Salas y Gomez Island

Biological oceanography, biogeochemical cycles, and pelagic ecosystem functioning of the east central South Pacific Gyre: focus on Easter Island and Salas y Gomez Island

Stomach contents and feeding observations of some Easter Island fishes

Patterns in sexual reproduction of the dominant scleractinian corals at Rapa Nui (Easter Island): Pocillopora verrucosa and Porites lobata

Contact Info

Product

Resources

About