The rapid evolution of non‐native species can facilitate invasion success, but recent reviews indicate that such microevolution rarely yields expansion of the climatic niche in the introduced habitats. However, because some invasions originate from a geographically restricted portion of the native species range and its climatic niche, it is possible that the frequency, direction, and magnitude of phenotypic evolution during invasion have been underestimated. We explored the utility of niche shift analyses in the red seaweed Gracilaria vermiculophylla, which expanded its range from the northeastern coastline of Japan to North America, Europe, and northwestern Africa within the last 100 years. A genetically informed climatic niche shift analysis indicates that native source populations occur in colder and highly seasonal habitats, while most non‐native populations typically occur in warmer, less seasonal habitats. This climatic niche expansion predicts that non‐native populations evolved greater tolerance for elevated heat conditions relative to native source populations. We assayed 935 field‐collected and 325 common‐garden thalli from 40 locations, and as predicted, non‐native populations had greater tolerance for ecologically relevant extreme heat (40°C) than did Japanese source populations. Non‐native populations also had greater tolerance for cold and low‐salinity stresses relative to source populations. The importance of local adaptation to warm temperatures during invasion was reinforced by evolution of parallel clines: Populations from warmer, lower‐latitude estuaries had greater heat tolerance than did populations from colder, higher‐latitude estuaries in both Japan and eastern North America. We conclude that rapid evolution plays an important role in facilitating the invasion success of this and perhaps other non‐native marine species. Genetically informed ecological niche analyses readily generate clear predictions of phenotypic shifts during invasions and may help to resolve debate over the frequency of niche conservatism versus rapid adaptation during invasion.

Theory predicts that the maintenance of haplodiplontic life cycles requires ecological differences between the haploid gametophytes and diploid sporophytes, yet evidence of such differences remain scarce. The haplodiplontic red seaweed Gracilaria vermiculophylla has invaded the temperate estuaries of the Northern Hemisphere, where it commonly modifies detrital and trophic pathways. In native populations, abundant hard substratum enables spore settlement, and gametophyte:tetrasporophyte ratios are ~40:60. In contrast, many non-native populations persist in soft-sediment habitats without abundant hard substratum, and can be 90%-100% tetrasporophytic. To test for ecologically relevant phenotypic differences, we measured thallus morphology, protein content, organic content, "debranching resistance" (i.e., tensile force required to remove a branch from its main axis node), and material properties between male gametophytes, female gametophytes, and tetrasporophytes from a single, nonnative site in Charleston Harbor, South Carolina, USA in 2015 and 2016. Thallus length and surface area to volume ratio differed between years, but were not significantly different between ploidies. Tetrasporophytes had lower protein content than gametophytes, suggesting the latter may be more attractive to consumers. More force was required to pull a branch from the main axis of tetrasporophytes relative to gametophytes. A difference in debranching resistance may help to maintain tetrasporophyte thallus durability relative to gametophytes, providing a potential advantage in free-floating populations. These data may shed light on the invasion ecology of an important ecosystem engineer, and may advance our understanding of life cycle evolution and the maintenance of life cycle diversity.

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More recently, forms of cobalamin produced by bacteria that contain adenine in place of 5,6-dimethylybenzimidazole in the -axial position [9,10] have been identifi ed and called pseudocobalamin. As a result many eukaryotes are unable to acquire pseudocobalamin; thereby, providing yet another point of infl uence on algal productivity [5,11]. Studies examining the role of cobalamins as a limiting nutrient that controls phytoplankton dynamics in lakes and oceans rely on accurate measurements of cobalamin variants.

Analysis of vitamin B12 in sea water is laborious, time consuming, and often requires storage of relatively large-volume water samples. Alleviating these major limitations will increase the throughput of samples and, as a consequence, improve our understanding of the distribution and role of vitamin B12 in the oceans. Previous studies have indicated that target analyte recovery is negatively affected at flow rates exceeding 1 mL min -1 using home-made C18 Solid Phase Extraction (SPE) cartridges. In this study, the effect of flow rate on recovery of vitamin B12 was tested across a range of flow rates between 1 and 37 mL min -1 using a commercial SPE cartridge containing surface-modified styrene divinylbenzene. Recovery of vitamin B12 at flow rates up to the maximum rate tested did not statistically differ from 1 mL min 1. A second study was conducted to determine whether storage of the SPE cartridges at -20°C had a negative impact on vitamin B12 recovery. Recovery of vitamin B12 from SPE cartridges stored up to 13 days did not differ from unfrozen SPE cartridges. These data suggest that rapid extraction and cold storage of vitamin B12 on commercial SPE cartridges does not negatively affect recovery and offers an economical alternative to field studies.