Floristic account of the marine benthic algae from Jarvis Island and Kingman Reef, Line Islands, Central Pacific

The marine benthic algae from Jarvis Island and Kingman Reef were identified from collections obtained from the Whippoorwill Expedition in 1924, the Itasca Expedition in 1935, the U.S. Coast Guard Cutter Taney in 1938, the Smithsonian Institution’s Pacific Ocean Biological Survey Program in 1964 and the U.S. National Oceanic and Atmospheric Administration’s Reef Assessment and Monitoring Program (RAMP) in 2000, 2001, 2002, 2004 and 2006. A total of 124 species, representing 8 Cyanobacteria (blue-green algae), 82 Rhodophyta (red algae), 6 Heterokontophyta (brown algae) and 28 Chlorophyta (green algae), are reported from both islands. Seventy-nine and 95 species of marine benthic algae are recorded from Jarvis Island and Kingman Reef, respectively. Of the 124 species, 77 species or 62% (4 blue-green algae, 57 red algae, 2 brown algae and 14 green algae) have never before been reported from the 11 remote reefs, atolls and low islands comprising the Line Islands in the Central Pacific

Phylogeny and taxonomy of <i>Halimeda incrassata</i>, including descriptions of <i>H. kanaloana</i> and <i>H. heteromorpha</i> spp. nov (Bryopsidales, Chlorophyta)

The tropical green algal genus Halimeda is one of the best studied examples of pseudo-cryptic diversity within the algae. Previous molecular and morphometric studies revealed that within Halimeda section Rhipsalis, Halimeda incrassata included three pseudo-cryptic entities and that the morphological boundaries between H. incrassata and Halimeda melanesica were ill-defined. In this paper, the taxonomy of H. incrassata is revised: two pseudo-cryptic entities are described as new species, Halimeda kanaloana and Halimeda heteromorpha, while H. incrassata is redefined to encompass a single, monophyletic entity. Similarities and differences between the three species and H. melanesica are discussed. Monophyly of H. heteromorpha, which was questioned in a former study, is reinvestigated using sets of 32 ITS1-ITS2 and 21 plastid rps3 sequences and various alignment and inference methods. The phylogenetic relationships within Halimeda section Rhipsalis are inferred from nuclear 18S-ITS1-5.8S-ITS2 and concatenated plastid sequences (tufA & rpl5-rps8-infA) and interpreted in a biogeographic context

Field biology of Halimeda tuna (Bryopsidales, Chlorophyta) across a depth gradient: comparative growth, survivorship, recruitment, and reproduction

Growth, survivorship, recruitment, and reproduction of Halimeda tuna, a dominant green alga in many reef systems of the Florida Keys, were monitored at a shallow back reef ( 4 - 7m) and deep reef slope ( 15 - 22 m) on Conch Reef. Despite lower light intensities and similar grazing pressures, amphipod infestations, and epiphyte loads at both sites, the deeper site exhibited significantly higher growth rates in summer months over a 4-year period than found for the shallow population, possibly because of higher nutrient levels at depth and photoinhibition of shallow plants. Sexual reproductive events occurred simultaneously across the entire reef, with up to 5% of the population at both sites developing gametangia. New upright axes formed from zygotes, asexual fragmentation, or vegetative runners. Plants appear to have persistent basal stumps that survive harsh environmental conditions, even if upright, photosynthetic axes are removed. Sexual reproduction and 'smothering' by epiphyte overgrowth are hypothesized to be two causes of death for individuals

Field biology of Halimeda tuna (Bryopsidales, Chlorophyta) across a depth gradient:comparative growth, survivorship, recruitment, and reproduction

Growth, survivorship, recruitment, and reproduction of Halimeda tuna, a dominant green alga in many reef systems of the Florida Keys, were monitored at a shallow back reef ( 4 - 7m) and deep reef slope ( 15 - 22 m) on Conch Reef. Despite lower light intensities and similar grazing pressures, amphipod infestations, and epiphyte loads at both sites, the deeper site exhibited significantly higher growth rates in summer months over a 4-year period than found for the shallow population, possibly because of higher nutrient levels at depth and photoinhibition of shallow plants. Sexual reproductive events occurred simultaneously across the entire reef, with up to 5% of the population at both sites developing gametangia. New upright axes formed from zygotes, asexual fragmentation, or vegetative runners. Plants appear to have persistent basal stumps that survive harsh environmental conditions, even if upright, photosynthetic axes are removed. Sexual reproduction and 'smothering' by epiphyte overgrowth are hypothesized to be two causes of death for individuals.</p