University of Maine

About: University of Maine is a education organization based out in Orono, Maine, United States. It is known for research contribution in the topics: Population & Ice sheet. The organization has 8637 authors who have published 16932 publications receiving 590124 citations. The organization is also known as: University of Maine at Orono.

Biology of deep-water octocorals.

Abstract: Publisher Summary This chapter discusses the taxonomy, phylogeny, biogeography, ecology, and reproductive biology of deep-sea octocorals and also focuses on gorgonian octocorals because they are the predominant octocoral group in the deep sea. The most widely accepted taxonomic scheme for octocorals divides the subclass into four orders: (1) helioporacea, (2) alcyonacea, (3) gorgonacea, and (4) pennatulacea. The distinctions between most orders and suborders are blurred by intermediate taxa that resulted in a continuum of colonial organization and skeletal structure. The major areas of study of deep-sea gorgonians and sources of species descriptions are also summarized. Octocorals have been known from deep water in the North Atlantic, although the Challenger expedition showed that octocorals could be found in the depths of all oceans. Knowledge of deep-water octocorals of the Indo-West Pacific region is meagre and contrasts with the wealth of information on shallow-water taxa. The distribution of the three major deep-sea families' discussed are––chrysogorgiidae, isididae, and primnoidae. Deep-sea octocoral colonies are often large so it offers a wide range of biogenic habitats to other invertebrate species. The chapter also focuses on those invertebrate species that are found most frequently on the octocoral host. Reproduction, growth, age, food habits, and conservation issues are also considered.

Paleoecological investigation of recent lake acidification in the Adirondack Mountains, N.Y.

Abstract: Paleoecological analysis of the sediment record of 12 Adirondack lakes reveals that the 8 clearwater lakes with current pH < 5.5 and alkalinity < 10 μeq l-1 have acidified recently. The onset of this acidification occurred between 1920 and 1970. Loss of alkalinity, based on quanitative analysis of diatom assemblages, ranged from 2 to 35 μeq l-1. The acidification trends are substantiated by several lines of evidence including stratigraphies of diatom, chrysophyte, chironomid, and cladoceran remains, Ca:Ti and Mn:Ti ratios, sequentially extracted forms of Al, and historical fish data. Acidification trends appear to be continuing in some lakes, despite reductions in atmospheric sulfur loading that began in the early 1970s. The primary cause of the acidification trend is clearly increased atmospheric deposition of strong acids derived from the combustion of fossil fuels. Natural processes and watershed disturbances cannot account for the changes in water chemistry that have occurred, but they may play a role. Sediment core profiles of Pb, Cu, V, Zn, S, polycyclic aromatic hydrocarbons, magnetic particles, and coal and oil soot provide a clear record of increased atmospheric input of materials associated with the combustion of fossil fuels beginning in the late 1800s and early 1900s. The primary evidence for acidification occurs after that period, and the pattern of water chemistry response to increased acid inputs is consistent with current understanding of lake-watershed acidification processes.

Molecular and culture-based analyses of aerobic carbon monoxide oxidizer diversity.

Abstract: Isolates belonging to six genera not previously known to oxidize CO were obtained from enrichments with aquatic and terrestrial plants. DNA from these and other isolates was used in PCR assays of the gene for the large subunit of carbon monoxide dehydrogenase (coxL). CoxL and putative coxL fragments were amplified from known CO oxidizers (e.g., Oligotropha carboxidovorans and Bradyrhizobium japonicum), from novel CO-oxidizing isolates (e.g., Aminobacter sp. strain COX, Burkholderia sp. strain LUP, Mesorhizobium sp. strain NMB1, Stappia strains M4 and M8, Stenotrophomonas sp. strain LUP, and Xanthobacter sp. strain COX), and from several well-known isolates for which the capacity to oxidize CO is reported here for the first time (e.g., Burkholderia fungorum LB400, Mesorhizobium loti, Stappia stellulata, and Stappia aggregata). PCR products from several taxa, e.g., O. carboxidovorans, B. japonicum, and B. fungorum, yielded sequences with a high degree (>99.6%) of identity to those in GenBank or genome databases. Aligned sequences formed two phylogenetically distinct groups. Group OMP contained sequences from previously known CO oxidizers, including O. carboxidovorans and Pseudomonas thermocarboxydovorans, plus a number of closely related sequences. Group BMS was dominated by putative coxL sequences from genera in the Rhizobiaceae and other alpha-PROTEOBACTERIA: PCR analyses revealed that many CO oxidizers contained two coxL sequences, one from each group. CO oxidation by M. loti, for which whole-genome sequencing has revealed a single BMS-group putative coxL gene, strongly supports the notion that BMS sequences represent functional CO dehydrogenase proteins that are related to but distinct from previously characterized aerobic CO dehydrogenases.