Frank Cipriano

N2 Fixation by Unicellular Bacterioplankton from the Atlantic and Pacific Oceans: Phylogeny and In Situ Rates

ABSTRACT N2-fixing proteobacteria (α and γ) and unicellular cyanobacteria are common in both the tropical North Atlantic and Pacific oceans. In near-surface waters proteobacterial nifH transcripts were present during both night and day while unicellular cyanobacterial nifH transcripts were present during the nighttime only, suggesting separation of N2 fixation and photosynthesis by unicellular cyanobacteria. Phylogenetic relationships among unicellular cyanobacteria from both oceans were determined after sequencing of a conserved region of 16S ribosomal DNA (rDNA) of cyanobacteria, and results showed that they clustered together, regardless of the ocean of origin. However, sequencing of nifH transcripts of unicellular cyanobacteria from both oceans showed that they clustered separately. This suggests that unicellular cyanobacteria from the tropical North Atlantic and subtropical North Pacific share a common ancestry (16S rDNA) and that potential unicellular N2 fixers have diverged (nifH). N2 fixation rates for unicellular bacterioplankton (including small cyanobacteria) from both oceans were determined in situ according to the acetylene reduction and 15N2 protocols. The results showed that rates of fixation by bacterioplankton can be almost as high as those of fixation by the colonial N2-fixing marine cyanobacteria Trichodesmium spp. in the tropical North Atlantic but that rates are much lower in the subtropical North Pacific.

GENETIC EVIDENCE ON THE DEMOGRAPHY OF SPECIATION IN ALLOPATRIC DOLPHIN SPECIES

Abstract Under a neutral model, the stochastic lineage sorting that leads to gene monophyly proceeds slowly in large populations. Therefore, in many recent species with large population size, the genome will have mixed support for monophyly unless historical bottlenecks have accelerated coalescence. We use genealogical patterns in mitochondrial DNA and in introns of four nuclear loci to test for historical bottlenecks during the speciation and divergence of two temperate Lagenorhynchus dolphin species isolated by tropical Pacific waters (an antitropical distribution). Despite distinct morphologies, foraging behaviors, and mitochondrial DNAs, these dolphin species are polyphyletic at all four nuclear loci. The abundance of shared polymorphisms between these sister taxa is most consistent with the maintenance of large effective population sizes (5.09 × 104 to 10.9 × 104) during 0.74–1.05 million years of divergence. A variety of population size histories are possible, however. We used gene tree coalescent probabilities to explore the rejection region for historical bottlenecks of different intensity given best estimates of effective population size under a strict isolation model of divergence. In L. obliquidens the data are incompatible with a colonization propagule of an effective size of 10 or fewer individuals. Although the ability to reject less extreme historical bottlenecks will require data from additional loci, the intermixed genealogical patterns observed between these dolphin sister species are highly probable only under an extended history of large population size. If similar demographic histories are inferred for other marine antitropical taxa, a parsimonious model for the Pleistocene origin of these distributions would not involve rare breaches of a constant dispersal barrier by small colonization propagules. Instead, a history of large population size in L. obliquidens and L. obscurus contributes to growing biological and environmental evidence that the equatorial barrier became permeable during glacial/interglacial cycles, leading to vicariant isolation of antitropical populations.

Diversity of Diazotrophic Unicellular Cyanobacteria in the Tropical North Atlantic Ocean

ABSTRACT We present data on the genetic diversity and phylogenetic affinities of N2-fixing unicellular cyanobacteria in the plankton of the tropical North Atlantic Ocean. Our dinitrogenase gene (nifH) sequences grouped together with a group of cyanobacteria from the subtropical North Pacific; another subtropical North Pacific group was only distantly related. Most of the 16S ribosomal DNA sequences from our tropical North Atlantic samples were closely allied with sequences from a symbiont of the diatom Climacodium frauenfeldianum. These findings suggest a complex pattern of evolutionary and ecological divergence among unicellular cyanobacteria within and between ocean basins.

Applied Conservation Genetics and the Need for Quality Control and Reporting of Genetic Data Used in Fisheries and Wildlife Management

Genetic data are often critical for defining populations for management purposes (e.g., identifying geographic boundaries or diagnostic characters for genetically discrete subunits) but can be called into question by both scientific and legal review. This can result in reversed or delayed implementation of management actions. We discuss methods for data quality control and quality analysis and describe examples of steps applied to 2 of the most common types of genetic data, mitochondrial DNA sequences, and microsatellite genotypes. These steps can serve both as guides to conservation geneticists and as an initial protocol for managers to determine whether genetic data will hold up against legal and scientific challenges. In addition, we suggest types of data and quality measures that should be reported as supplementary materials to published reports. These supplementary data serve to reduce the occurrence of legal and conservation controversies and improve reproducibility over time in population genetics studies where genetic monitoring is likely to play an increasing role.

Genetic tracking of a protected whale

Unusual circumstances have allowed us to trace the life of an individual whale, from its conception in the North Atlantic in 1964 to its sale as raw meat in Osaka, Japan, in 1993. We documented genetic polymorphisms in nuclear and mitochondrial genes of the Osaka meat and showed that they exactly matched those of a naturally occurring blue/fin whale hybrid harpooned near Iceland in 1989. This genetic match allowed us to trace the pathway of this individual from ocean to market. Such techniques can be useful in genetic monitoring programmes developed for the future regulation of the whaling industry and for international management of whale stocks.

How many protected minke whales are sold in Japan and Korea? A census by microsatellite DNA profiling

Products from the protected East Sea/Sea of Japan (‘J’ stock) minke whales (Balaenoptera acuturostrata) are sold widely on the commercial markets of Japan and Korea despite the protection of this stock since 1986. To determine the minimum number of individual whales for sale, genotypes from six microsatellite loci were used to profile North Pacific (NP) minke whale products purchased on these markets between December 1997 and October 1999. Genotype differences showed that 99 NP minke whale products from the Japanese market represented 86 unique individuals. Of these, 33.7% were of likely J-stock origin based on mitochondrial (mt) DNA haplotypes. In Korea, genotyping showed that 23 NP minke products from March 1999 represented 18 individuals, and 19 products from October 1999 represented 16 individuals. No matches were found between the two sampling periods, giving a total of 34 unique individuals. A frequency-of-capture model suggests that 98 minke whales were present on the Korean market over the two brief sampling periods. No genotype matches were confirmed between the two countries, indicating that undocumented exploitation of this depleted stock must be additive, and greater than previously assumed.

Atlantic White-Sided Dolphin: Lagenorhynchus acutus

Publisher Summary This chapter describes the Atlantic white-sided dolphins that are robust and powerful, impressively patterned, and more colorful than most dolphins. A narrow, bright white patch on the side extends back from below the dorsal fin and continues toward the flukes as a yellow brown blaze above a thin dark stripe. The back and dorsal fin are black or very dark gray, as are the flippers and flukes, while the belly and lower jaw are white, and the sides of the body a lighter gray. A black eye ring extends in a thin line to the upper jaw, and a very thin stripe extends backward from the eye ring to the external ear. A faint gray stripe may connect the leading edge of the flipper with the rear margin of the lower jaw. The beak is short and grades smoothly into the “melon” (forehead). The upper jaw contains 29–40 and the lower jaw 31–38 small, conical teeth. Molecular analysis has recently been used to examine the evolutionary relationships of Lagenorhynchus acutus and the five other currently recognized members of the genus Lagenorhynchus. Although formal taxonomic revision awaits a comprehensive review of morphological and molecular characters, the molecular evidence suggests that some of the five are actually more closely related to the right whale dolphins (genus Lissodelphis) and some Southern Hemisphere dolphins (genus Cephalorhynchus) than they are to L. acutus.

Dusky Dolphin Life History and Demography

Publisher Summary With five other dolphin species, dusky dolphins ( Lagenorhynchus obscurus ), are currently classified in the genus Lagenorhynchus , but that is likely to change in the near future once the details are better understood. Analysis of full-length cytochrome b DNA sequences by LeDuc and coauthors gave the first evidence that the current naming scheme, which implies that all six species are closely related by placing them in a single genus, is incorrect. Although the final assignment of genus names to the species awaits detailed study and formal taxonomic review and publication, the new understanding of evolutionary relationships within this group has been recognized in several recent papers, which place all but the two North Atlantic species into subfamily Lissodelphininae. Morphological evidence suggests differentiation, possibly at the subspecies level, between geographically distinct dusky dolphin populations. Molecular data provide further evidence for significant differentiation. There is tantalizing evidence that dusky dolphins from Argentina and Southern Africa recently separated from an ancestral Atlantic population, although not all agree with this conclusion and instead suggest a Pacific/Indian Ocean source population. Formal taxonomic consideration of subspecies status awaits concentrated study utilizing both morphological and molecular analysis.

Stranding of a Commerson's dolphin, Cephalorhynchus commersonii, in Buenos Aires Province, Argentina

miguel in~i’guez, marta hevia, frank cipriano, javier sarradell and ricardo doumecq milieu Fundacion Cethus, Potosi 2087, (B1636BUA), Olivos, Pcia, Buenos Aires, Argentina, Whale and Dolphin Conservation Society, Brookfield House, 38 St Paul Street, Chippenham, SN15 1LJ, UK, Conservation Genetics Laboratory, San Francisco State University, San Francisco, CA 94132, USA, General and Special Pathology, Veterinary Faculty, National University of Rosario, Santa Fe Province, Argentina, Calle 54 n8 2726 (7630) Necochea, Pcia, Buenos Aires, Argentina