Publications

Antimalarial Bromophycolides J−Q from the Fijian Red Alga <i>Callophycus serratus</i>

Bromophycolides J-Q (1-8) were isolated from extracts of the Fijian red alga Callophycus serratus and identified with 1D and 2D NMR spectroscopy and mass spectral analyses. These diterpene-benzoate macrolides represent two novel carbon skeletons and add to the 10 previously reported bromophycolides (9-18) from this alga. Among these 18 bromophycolides, several exhibited activities in the low micromolar range against the human malaria parasite Plasmodium falciparum.

Within-plant variation in seaweed palatability and chemical defenses: optimal defense theory versus the growth-differentiation balance hypothesis

Crustaceans as Powerful Models in Aquatic Chemical Ecology

Multalism between Harvester Ants and a Desert Ephemeral: Seed Escape from Rodents

The harvester ants Veromessor pergandei and Pogonomyrmex californicus modify the highly localized seed shadow of the Sonoran Desert ephemeral Datura discolor (Solanaceae) through (1) attraction to food bodies attached to seeds released beneath the parent plant, (2) immediate transport of disapores to the ant nest, (3) subsequent removal of the food body in underground granaries, and (4) final expulsion of intact seeds onto the colony midden. D. discolor seed without food bodies are not attractive to ants and remain beneath the parent canopy. At Nude Wash, California, USA, diaspore removal distances are generally small, averaging 2.3 m away from the nearest D. discolor canopy in March—May 1977. Two lines of evidence indicate that this limited transport has a large effect on seed detection and utilization by rodents: (1) seeds placed in ant—proof dishes beneath the D. discolor canopy were about 10 times more likely to be removed by nocturnally foraging rodents than seeds placed in locations similar to those where ants locate their nests; (2) using D. discolor as bait, significantly more rodents were trapped beneath the plant canopy than in open areas where seeds were transported by ants. Manipulation of the density of D. discolor seed in these tests suggests that seed utilization by rodents is distance—responsive to the parent canopy rather than dependent on the density of seeds. Disapore analyses indicate that investment in the transport system is relatively small and represents &lt;5% of the total investment in seeds.

Functional morphology of intertidal seaweeds; adaptive significance of aggregate vs. solitary forms

Many intertidal seaweeds show a tremendous gradient of morphological form ranging from spatially separated thalli, to thalli that are aggregated into dense turfs.Aggregation of seaweeds into turfs decreases productivity per g organic weight due to crowding of thalli but increases resistance to desiccation.The intertidal distribution of the turf growth form is correlated with the intensity of desiccation stress.Also turfs transplanted into tide pools developed the non-turf morphology, while non-turfs transplanted to emergent substrate either developed the turf form or died.The turf growth form is energetically expensive; apparent productivity of turfs was 23 to 48 % less than that of individuals.Increasing light and nutrients available to turfs by separating the thalli increased apparent productivity by 36 to 113 %.We tested the hypothesis that these turfs minimize energetic costs of this aggregated growth form through the spatial partitioning of photosynthetic and respirative activity.The lower portions of turfs showed less apparent photosynthesis than the upper portions (reductions of 37 to 85 %); however, this spatial partitioning was also found in the individual forms (37 to 63 % reductions) of these relatively simple seaweeds.Spatial differentiation of respiration was similar in turfs and nonturfs.The seaweeds, examined are able to alter the extent of thalli compaction in accordance with varying levels of environmental stress.This phenotypic plasticity allows seaweeds to adopt morphological features that maximize fitness in a wide variety of habitats without being developmentally committed.

Faculty Opinions recommendation of Janzen-Connell effects are widespread and strong enough to maintain diversity in grasslands.

Seasonal reproduction and abundance of six sympatric species of Gracilaria Grev. (Gracilariaceae; Rhodophyta) on a Caribbean subtidal sand plain

Faculty Opinions recommendation of Opposing plant community responses to warming with and without herbivores.

Strong Impacts of Grazing Amphipods on the Organization of a Benthic Community

MARINE PLANT-HERBIVORE INTERACTIONS: The Ecology of Chemical Defense

Herbivory has a profound effect on seaweeds in both temperate and tropical communities (11, 17, 21, 33, 43, 47, 80, 124). This is especially true on coral reefs where 60-97% (11, 42) of the total seaweed production may be removed by herbivores. To persist in marine communities, seaweeds must escape, deter, or tolerate herbivory. The ecological and evolutionary importance of spatial and temporal escapes has been extensively studied for seaweeds and adequately reviewed in the recent literature (33, 45, 47, 71, 80). The ability of seaweeds to tolerate herbivory has received limited attention. On coral reefs, rapidly growing filamentous algae are heavily grazed, but the algae quickly replace these losses and appear to be dependent upon herbivores to prevent their habitat from being overgrown by larger but less herbivoretolerant species (11, 71). Additionally, several seaweeds have spores or vegetative portions that can withstand gut passage; in some cases this significantly increases the growth rates of the newly settled spores (6, 122). These types of seaweeds may be considered herbivore tolerant. Although numerous seaweed characteristics can deter some herbivores, the effects of morphology and chemistry have been studied most thoroughly. The

Effects of Food Deprivation on Midbrain 5-HT 1A Autoreceptors in Lewis and SHR Rats

Successful restoration of seagrass beds

Ecosystem Recovery Since 1999, broadcasting more than 70 million seeds of the seagrass Zostera marina into coastal lagoons in Virginia has led to the reestablishment of more than 3600 hectares of previously lost seagrass beds. Orth et al. found that seagrass recovery led to rapid increases in the production and diversity of animals, increases in carbon and nitrogen sequestration, decreases in turbidity, and increases in previously depleted bay scallops. This is one of the larger success stories of ecosystem restoration and demonstrates that reversal of ecological collapse is possible when sustained initial efforts lead to positive feedbacks that support ecosystem recovery. Sci. Adv. 10.1126/sciadv.abc6434 (2020).

Two antifeedant lignans from the freshwater macrophyte Saururus cernuus

Ambiguous role of phlorotannins as chemical defenses in the brown alga Fucus vesiculosus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 277:79-93 (2004) - doi:10.3354/meps277079 Ambiguous role of phlorotannins as chemical defenses in the brown alga Fucus vesiculosus Julia Kubanek1,2,*, Sarah E. Lester3, William Fenical4, Mark E. Hay1 1School of Biology, and 2School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0230, USA 3Department of Ecology, Evolution and Marine Biology, University of California at Santa Barbara, Santa Barbara, California 93106, USA 4Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204, USA *Email: julia.kubanek@biology.gatech.edu ABSTRACT: Brown seaweeds (Fucales) produce phlorotannins that are often considered chemical defenses against herbivores. The many correlative and fewer direct tests conducted have shown effects of phlorotannins on herbivore feeding behavior to be variable. In an attempt to clarify the roles of phlorotannins versus other metabolites in defending brown algae, we conducted bioassay-guided fractionation of herbivore-deterrent extracts from the commonly studied brown alga Fucus vesiculosus. Feeding by the amphipods Ampithoe valida and A. longimana and the sea urchin Arbacia punctulata was suppressed by crude and water-soluble extracts of F. vesiculosus, but this deterrence was lost following storage or fractionation of the active, water-soluble extract. Phlorotannins in these extracts did not decompose in parallel with the loss of feeding deterrence. F. vesiculosus phlorotannins were fed to herbivores at 3 to 12× the isolated yield (or 4.2 to 16.8% of plant dry mass). No herbivore was deterred from feeding by concentrations of 3 or 6×, but A. valida (the only test herbivore that readily consumes F. vesiculosus in the field) was deterred at 12× isolated yield. When juvenile A. valida were raised on an artificial diet containing F. vesiculosus phlorotannins at 3× isolated yield, the phlorotannin-rich diet significantly enhanced, rather than reduced, amphipod survivorship and growth relative to an equivalent diet without phlorotannins. Females ovulated only on the phlorotannin-rich diet. Compounds other than phlorotannins appear to defend the F. vesiculosus populations we investigated, but we were unable to identify these unstable compounds. KEY WORDS: Phlorotannin · Fucus vesiculosus · Chemical defense · Plant-herbivore interaction · Amphipod · Urchin Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 277. Online publication date: August 16, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Effects of ocean acidification on the potency of macroalgal allelopathy to a common coral

Faculty Opinions recommendation of Effect of natural iron fertilization on carbon sequestration in the Southern Ocean.

Bioassays with Marine and Freshwater Macroorganisms