Twentieth Century Delta δC Variability in Surface Water Dissolved Inorganic Carbon Recorded by Coralline Algae in the Northern North Pacific Ocean and the Bering Sea

The oxygen isotopic composition and Mg/Ca ratios in the skeletons of long-lived coralline algae record ambient seawater temperature over time. Similarly, the carbon isotopic composition in the skeletons record delta(13)C values of ambient seawater dissolved inorganic carbon. Here, we measured delta(13)C in the coralline alga Clathromorphum nereostratum to test the feasibility of reconstructing the intrusion of anthropogenic CO(2) into the northern North Pacific Ocean and Bering Sea. The delta(13)C was measured in the high Mgcalcite skeleton of three C. nereostratum specimens from two islands 500 km apart in the Aleutian archipelago. In the records spanning 1887 to 2003, the average decadal rate of decline in delta(13)C values increased from 0.03% yr(-1) in the 1960s to 0.095% yr(-1) in the 1990s, which was higher than expected due to solely the delta(13)C-Suess effect. Deeper water in this region exhibits higher concentrations of CO(2) and low delta(13)C values. Transport of deeper water into surface water (i.e., upwelling) increases when the Aleutian Low is intensified. We hypothesized that the acceleration of the delta(13)C decline may result from increased upwelling from the 1960s to 1990s, which in turn was driven by increased intensity of the Aleutian Low. Detrended delta(13)C records also varied on 4-7 year and bidecadal timescales supporting an atmospheric teleconnection of tropical climate patterns to the northern North Pacific Ocean and Bering Sea manifested as changes in upwelling.

Cladorhiza corona sp. nov. (Porifera : Demospongiae : Cladorhizidae) from the Aleutian Islands (Alaska)

A new species of Cladorhizidac, front the Aleutian Islands is described and compared with all known species of Cladorhizza worldwide. Cladorhiza corona sp. now has a unique growth form with two planes of differently shaped appendages. Appendages are Inserted directly at the stalk; a spherical or conical body at the stalk is lacking. It is the only species reported where different spicule types occur in three morphologically different areas of the sponge. The spiculation of the basal plate is characterized by the occurrence of short, thick anisoxcas and the lack of anisochelae. Anisochelac arc found in the stalk and the basal appendages only. Flattened sigmancistras and (sub-)tylostyles are restricted to the crown. The arrangement of spicules is different in the basal plate, the stalk with the basal appendages, and in the distal append ages. The dimensions and combination of spicule types separate C. corona sp. nov. from all known members of the genus.

Physiological Responses to Environmental Variation in Intertidal Red Algae: Does Thallus Morphology Matter?

Morphological variation within and among many species of algae show correlated life history traits. The trade-offs of Life history traits among different morphs are presumed to be determined by morphology. Form-function hypotheses also predict that algae of different morphological groups exhibit different tolerances to physiological stress, whereas algae within a morphological group respond similarly to stress. We tested this hypothesis by comparing photosynthetic and respiratory responses to variation in season, light, temperature, desiccation and freezing among the morphologically similar fronds of Chondrus crispus and Mastocarpus stellatus and the alternate stage crust of M. stellatus. Physiological differences between fronds of the 2 species and crusts and fronds were consistent with their patterns of distribution and abundance in the intertidal zone. However, there was no clear relationship between algal morphology and physiological response to environmental variation. These results suggest that among macroalgae the correlation between Life history traits and morphology is not always causal. Rather, the link between life history traits and morphology is constrained by the extent to which physiological characteristics codetermine these features.