The role of chitin-rich skeletal organic matrix on the crystallization of calcium carbonate in the crustose coralline alga Leptophytum foecundum.

The organic matrix (OM) contained in marine calcifiers has a key role in the regulation of crystal deposition, such as crystalline structure, initiation of mineralization, inhibition, and biological/environmental control. However, the functional properties of the chitin-rich skeletal organic matrix on the biological aspect of crystallization in crustose coralline algae have not yet been investigated. Hence, the characterization of organic matrices in the biomineralization process of this species was studied to understand the functions of these key components for structural formation and mineralization of calcium carbonate crystals.

Sequencing type material resolves the identity and distribution of the generitype Lithophyllum incrustans, and related European species L. hibernicum and L. bathyporum (Corallinales, Rhodophyta).

DNA sequences from type material in the nongeniculate coralline genus Lithophyllum were used to unambiguously link some European species names to field-collected specimens, thus providing a great advance over morpho-anatomical identifi-cation. In particular, sequence comparisons of rbcL, COI and psbA genes from field-collected specimens allowed the following conclusion: the generitype species, L. incrustans, occurs mostly as subtidal rhodoliths and crusts on both Atlantic and Mediterranean coasts, and not as the common, NE Atlantic, epilithic, intertidal crust reported in the literature.

DNA sequencing, anatomy, and calcification patterns support a monophyletic, subarctic, carbonate reef-forming Clathromorphum (Hapalidiaceae, Corallinales, Rhodophyta).

For the first time, morpho-anatomical characters that were congruent with DNA sequence data were used to characterize several genera in Hapalidiaceae-the major eco-engineers of Subarctic carbonate ecosystems. DNA sequencing of three genes (SSU, rbcL, ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene and psbA, photosystem II D1 protein gene), along with patterns of cell division, cell elongation, and calcification supported a monophyletic Clathromorphum. Two characters were diagnostic for this genus: (i) cell division, elongation, and primary calcification occurred only in intercalary meristematic cells and in a narrow vertical band (1-2 μm wide) resulting in a "meristem split" and (ii) a secondary calcification of interfilament crystals was also produced.

Evolution of the Northern Rockweed, Fucus distichus, in a Regime of Glacial Cycling: Implications for Benthic Algal Phylogenetics.

Northern hemisphere rockweeds (Fucus) are thought to have evolved in the North Pacific and then spread to the North Atlantic following the opening of the Bering Strait. They have dispersed and widely speciated in the North Atlantic and its tributary seas. Fucus distichus is likely near the ancestral member of this genus, and studies have shown that there are several species/subspecies in this complex (i.

Arctic sea-ice decline archived by multicentury annual-resolution record from crustose coralline algal proxy.

Northern Hemisphere sea ice has been declining sharply over the past decades and 2012 exhibited the lowest Arctic summer sea-ice cover in historic times. Whereas ongoing changes are closely monitored through satellite observations, we have only limited data of past Arctic sea-ice cover derived from short historical records, indirect terrestrial proxies, and low-resolution marine sediment cores. A multicentury time series from extremely long-lived annual increment-forming crustose coralline algal buildups now provides the first high-resolution in situ marine proxy for sea-ice cover.

Algal turf scrubber (ATS) floways on the Great Wicomico River, Chesapeake Bay: productivity, algal community structure, substrate and chemistry(1).

Two Algal Turf Scrubber (ATS) units were deployed on the Great Wicomico River (GWR) for 22 months to examine the role of substrate in increasing algal productivity and nutrient removal. The yearly mean productivity of flat ATS screens was 15.4 g · m(-2)  · d(-1) .

MESOPHYLLUM SPHAERICUM SP. NOV. (CORALLINALES, RHODOPHYTA): A NEW MAËRL-FORMING SPECIES FROM THE NORTHEAST ATLANTIC(1).

Mesophyllum sphaericum sp. nov. is described based on spherical maërl individuals (up to 10 cm) collected in a shallow subtidal maërl bed in Galicia (NW Spain).

THE BIOGEOGRAPHIC ORIGIN OF ARCTIC ENDEMIC SEAWEEDS: A THERMOGEOGRAPHIC VIEW(1).

The Arctic is geologically and biogeographically young, and the origin of its seaweed flora has been widely debated. The Arctic littoral biogeographic region dates from the latest Tertiary and Pleistocene. Following the opening of Bering Strait, about 3.