Anthropogenic disturbances, including coastal habitat modification and climate change are threatening the stability of kelp beds, one of the most diverse and productive marine ecosystems. To test the effect of temperature and irradiance on the microscopic gametophyte and juvenile sporophyte stages of the rare kelp, Saccharina angustissima, from Casco Bay, Maine, USA, we carried out two sets of experiments using a temperature gradient table. The first set of experiments combined temperatures between 7-18 degrees C with irradiance at 20, 40, and 80 mu mol photons m(-2) s(-1). The second set combined temperatures of 3-13 degrees C with irradiance of 10, 100, and 200 mu mol photons m(-2) s(-1). Over two separate 4-week trials, in 2014 and again in 2015, we monitored gametogenesis, the early growth stages of the gametophytes, and early sporophyte development of this kelp. Gametophytes grew best at temperatures of 8-13 degrees C at the lowest irradiance of 10-mu mol photons m(-2) s(-1). Light had a significant effect on both male and female gametophyte growth only at the higher temperatures. Temperatures of 8-15 degrees C and irradiance levels of 10-100 mu mol photons m(-2 )s(-1) were conditions for the highest sporophyte growth. Sporophyte and male gametophyte growth was reduced at both temperature extremes-the hottest and coldest temperatures tested. S. angustissima is a unique kelp species known only from a very narrow geographic region along the coast of Maine, USA. The coupling of global warming with high light intensity effects might pose stress on the early life-history stages of this kelp, although, as an intertidal species, it could also be better adapted to temperature and light extremes than its subtidal counterpart, Saccharina latissima.
Saccharina latissima is a perennial kelp with a circumboreal distribution from the North Pacific to the North Atlantic coasts. Our study clarified the taxonomy of the morphologically distinct Saccharina latissima forma angustissima (Collins) A. Mathieson from the low intertidal zone on exposed islands and ledges of Casco Bay, Maine, USA. To identify genetic divergence between the two morphotypes, S. latissima and S. latissima f. angustissima, we used a multilocus phylogenetic approach including nuclear-encoded internal transcribed spacer, mitochondrial cox1 and cox3, and plastid-encoded rbcL gene sequences. Genetic analysis of the individual markers and combined data set using SVDquartets resulted in p-distance values for all markers of, 1%, suggesting low divergence between the two forms. However, there was as much or more genetic divergence between S. latissima and S. latissima f. angustissima as there were between other taxonomically accepted species of Saccharina. To investigate sexual compatibility between the two forms, we made reciprocal crosses of the gametophytes and observed sporophyte formation. All crosses were successfully grown to the juvenile sporophyte stage, suggesting that the two are reproductively compatible in vitro. It is unknown if the two populations freely hybridize in the field. Last, we compared wave action, the ecological factor most likely driving the unique morphology, at exposed sites with S. latissima f. angustissima and protected sites with S. latissima. The mean wave force at the exposed site was over 30 times higher in magnitude than at the protected site at 160.04 +/- 32.58 N and 4.75 +/- 6.75 N, respectively, during the summer. The significant differences in morphology, the lack of specimens with intermediate morphologies, and the results of a common garden experiment suggest that the morphological differences in S. latissima f. angustissima are heritable with a genetic basis. Therefore, on the basis of our molecular evidence coupled with ecological studies, we are elevating S. latissima f. angustissima (Collins) A. Mathieson to specific rank as S. angustissima (Collins) Augyte, Yarish & Neefus comb. nov. & stat. nov.
Seaweed aquaculture in the Northwest Atlantic has been steadily increasing with five commercial kelp farms already established. Currently, kelp production is limited to winter and spring, and new seaweed crops need to be developed in order to supplement seasonal kelp production. Porphyra umbilicalis is a member of the most economically valuable group of seaweeds known by the Japanese name nori. It is an ideal candidate for aquaculture since it exhibits short production cycles, rapid growth, high nutrient uptake rates, and high pigment and protein content. Further, sexual reproduction appears to be absent in populations in the Northwest Atlantic, which considerably simplifies the production of seed stock. The goal of this study was to determine the conditions that optimize growth, photosynthetic efficiency of photosystem II (F v/F m), and pigment and protein content of P. umbilicalis. Cultured blades were grown under a matrix of temperatures (10, 15, and 20 °C), light levels (30, 60, 110, and 250 μmol photons m−2 s−1), and photoperiods (8:16, 12:12, and 16:8 light/dark) in a factorial design for 4 weeks. Growth rates were highest (>9 % day−1) in blades grown between 10 and 15 °C, with light levels ≥110 μmol photons m−2 s−1 and ≥12 h of light in the day. F v/F m was significantly affected by photoperiod with this effect dependent on light level; the overall range of F v/F m values was small. Here, we report detailed information on the growth rate, F v/F m,, and pigment and protein content of P. umbilicalis grown under 36 treatment combinations. These results provide physiological information on P. umbilicalis from the Northwest Atlantic that will aid in the development of P. umbilicalis aquaculture on a commercial scale.
This year’s recipients of the New England Botanical Club’s Merritt Lyndon Fernald Award are Jeremy C. Nettleton, Arthur C. Mathieson, Carol Thornber, Christopher D. Neefus, and Charles Yarish for their paper entitled “Introduction of Gracilaria vermiculophylla (Rhodophyta, Gracilariales) to New England, USA: Estimated Arrival Times and Current Distribution” published in Rhodora 115 (961): 28-41 (January)
Effective workflows are essential components in the digitization of biodiversity specimen collections. To date, no comprehensive, community-vetted workflows have been published for digitizing flat sheets and packets of plants, algae, and fungi, even though latest estimates suggest that only 33% of herbarium specimens have been digitally transcribed, 54% of herbaria use a specimen database, and 24% are imaging specimens. In 2012, iDigBio, the U.S. National Science Foundation's (NSF) coordinating center and national resource for the digitization of public, nonfederal U.S. collections, launched several working groups to address this deficiency. Here, we report the development of 14 workflow modules with 7-36 tasks each. These workflows represent the combined work of approximately 35 curators, directors, and collections managers representing more than 30 herbaria, including 15 NSF-supported plant-related Thematic Collections Networks and collaboratives. The workflows are provided for download as Portable Document Format (PDF) and Microsoft Word files. Customization of these workflows for specific institutional implementation is encouraged.
Seaweed aquaculture in the Northwest Atlantic is a growing industry that is currently based on winter-spring kelp production. Aquaculture of Pyropia leucosticta, a species of economically valuable nori, could provide a spring-summer crop and diversify the industry. The objectives of this study were to determine the optimum conditions for the production of the foliose blade phase and the conditions for advancement from the microscopic conchocelis to the foliose blade phase of P. leucosticta. Foliose blades were grown under a matrix of temperatures (10, 15, and 20 °C), photoperiods (8:16, 12:12, and 16:8 L:D), and light levels (30, 60, 110, and 250 μmol photons m−2 s−1) for a period of 1 month. Free-living conchocelis was grown under a matrix of temperatures (10, 15, and 20 °C), photoperiods (8:16, 12:12, and 16:8 L:D), and ammonium concentrations (20 and 500 μM) for 8–12 weeks. Blades grew optimally at 10 to 15 °C, ≥110 μmol photons m−2 s−1 and ≥12 h of light in the day, with growth rates of over 18 % day−1 recorded. Phycobilin content of blades significantly decreased with increasing day length, while protein content significantly decreased with increasing light level. Conchospore release and germination was observed after approximately 40 days under all tested photoperiods, temperatures, and ammonium concentrations and none of these treatments significantly affected the time until germination. Overall, this study provides important background information required for the establishment of Pyropia leucosticta aquaculture in the Northwest Atlantic.
The consequences of initial variability in reproductive effort on later pollination and fruit development have frequently been investigated with flower removal experiments. Often, plants produce many fewer fruits than flowers, so flower removal might not be expected to alter subsequent growth or development patterns all that much. Yet, many studies have demonstrated such changes even for species with low average fruit set, which begs for an explanation. Many (at least seven, by our count) such explanations have been reported in the literature, but experimental support for most is limited. In summer 2014, we conducted a field experiment on a lowbush blueberry (Vaccinium angustifolium) farm in Maine. In this experiment, we coupled flower removal with three other treatments, each designed to assess the validity of one of three often-cited hypotheses invoked to explain why growth and development changes occur following flower removal: 1) “Short-term nutrient shortages;” 2) “spatiotemporal limitations;” and 3) “the compound interest effect.” The three respective treatments—foliar nitrogen fertilization, positionally biased flower removal, and defoliation—were designed to either intensify or weaken the apparent effects of flower removal if the corresponding hypothesis had merit. As in a 2013 preliminary experiment, flower removal elicited several statistically significant growth and development changes in blueberry, including increases in final leaf area, ripe fruit weight, fruit ripening rate, and relative fruit production. The additional treatments also elicited several significant plant responses, though not always with concomitant flower removal effects as well. For example, fertilization generally increased fruit cluster mass by harvest, but flower removal itself had no such effect on cluster mass. Most observed interactive effects between flower removal and the additional treatments either ran counter to expectations, were limited in scope, or couldn't be unambiguously interpreted. For at least a few observed changes, none of the additional treatments significantly altered the effects of flower removal. We conclude that current hypotheses for the mechanistic basis for changes induced by flower removal are inadequate, at least for blueberry, a species with frequently low fruit set even when managed commercially. However, strong intellectual and economic imperatives exist to encourage further investigation into this open question.Plants grown in horticulture or occurring as adventives outside their native range can provide insight into species’ fundamental niche requirements that might not be evident from the native range, or realized niche, alone. Such occurrences can also identify conditions that support individual survival, but do not currently sustain positive population growth (i.e., a species’ ‘tolerance niche’). Further, in the context of rapid climate change, horticultural and adventive occurrences beyond current range edges might circumvent natural dispersal limitations and facilitate species range shifts. To explore these concepts in the field, we investigated the history and structure of five newly discovered populations of naturalized Magnolia tripetala near horticultural sites in western Massachusetts, USA. This tree species is native to the southeastern US, but has been grown horticulturally in the Northeast since the 1800s. However, naturalized populations had not been well documented in the region previously, raising the possibility that the species’ escape has been triggered by recent climate change. With tree coring and life stage surveys, we asked whether the naturalized populations exhibited synchronous patterns of establishment and expansion, suggestive of climatic release and a shift from tolerance niche to fundamental niche conditions in the region. Across the five sites, we documented 660 individuals, with populations ranging in size from 46 to 396 individuals, including seedlings, saplings, and reproduct
Greenland is a continental island in the northern part of the North Atlantic where the foliose Bangiales flora is poorly known. It is an important area for the study of algal biogeography because of the region’s glacial history, in which Greenland has been alternately exposed to or isolated from the North Pacific via the Bering Strait. A molecular study using 3′ rbcL + 5′ rbcL–S sequences was undertaken to assess the diversity of foliose Bangiales on the west coast of Greenland and rbcL sequences were used to study the Greenland flora in a larger phylogenetic and floristic context. New and historic collections document seven species in four genera from the west coast of Greenland. All species had a close link to North Pacific species, being either conspecific with them or North Atlantic–North Pacific vicariant counterparts.
Seaweeds inhabiting the upper intertidal zone are subjected to temperature, light, and water stresses and vertical distribution has been linked to environmental tolerance. Previous studies have also attributed successful recovery from freezing stress in intertidal seaweeds to desiccation tolerance. Potphyra umbilicalis Razing is an aseasonal red alga inhabiting the mid to upper intertidal zone in temperate and subarctic regions of the North Atlantic. It is a member of the economically important group of foliose Bangiales, and has been documented to only reproduce asexually via neutral spores in the Northwest Atlantic. The goal of this study was to assess the effects of freezing on the viability of small blades of P. umbilicalis. Cultured blades of P. umbilicalis (4.8 +/- 0.22 mg) were air dried to 5% or 30% absolute water content (AWC) and frozen for 1, 3, 6, or 12 months at -80 degrees C or -20 degrees C. Following freezing, blades were rehydrated and the growth rate of each blade was measured weekly for 4 weeks. Photosynthetic efficiency of photosystem II (Fv/Fn,) was assessed for each blade 3 h and 4 weeks post-rehydration. Overall, there was 100% blade survival and all blades continued to grow after rehydration. Although the conditions under which the blades were frozen did have statistically significant effects on post-rehydration growth rate and F-v/F-m in general the differences were quite small. Post-rehydration growth rates ranged from 7.06 to 8.03 +/- 0.16% day(-1). AWC had an effect on post-rehydration growth rates for blades frozen at -80 degrees C, but not blades frozen at -20 degrees C The length of freezing had a somewhat greater effect on blades with 5% AWC than blades with 30% AWC. Growth rates peaked two weeks post-rehydration followed by a small decline in weeks 3 and 4. F-v/F-m values following freezing were generally similar to those recorded in previous studies on non-frozen blades; however, blades frozen for 6 months performed better than blades frozen for 12 months. Overall, these results indicate that short- and long-term freezing have little physiological effect on blades of P. umbilicalis. Therefore, freezing may be a viable method for preservation of P. umbilicalis for aquaculture. (C) 2014 Elsevier B.V. All rights reserved.
The invasive Asiatic red alga Gracilaria vermiculophylla has recently spread rapidly around the globe. In the Northwest Atlantic, it was first collected in Virginia during 1998; in New England, it was first recorded from Narragansett Bay, Rhode Island in 2007. Until now, the specific dates of its introduction and current distribution in New England have been poorly understood. We employed a combination of field collections, evaluations of historical herbarium specimens, and molecular investigations (including mt-CO1 gene sequencing) to document its present distribution and approximate dates of introduction within New England. We found G. vermiculophylla at 18 of 24 Northwest Atlantic sites growing with native Gracilaria populations. Presently, it is recorded from Stamford, CT to Greenland, NH, with no populations known from five Maine sites where the native G. tikvahiae grows. Molecular screening of historical specimens revealed that G. vermiculophylla was collected from five sites in Massachusetts during 2000, whereas it was first documented in New Hampshire from the middle of the Great Bay Estuarine System (i.e., Dover Point) during 2003. In Rhode Island, initial specimens were documented during 2007, and those in Connecticut were first confirmed during 2010. As G. vermiculophylla has gone primarily undetected in New England since at least 2000, this highlights the difficulty of documenting the arrival and spread of an invasive species that closely resembles a native congener. Hence, DNA sequencing is critical in clarifying the introduction and expansion of such non-native seaweeds.
It was with great excitement that we planned the combined meetings of Northeast Aquaculture Conference and Exposition (NACE) and the International Conference on Shellfish Restoration (ICSR) with the 33rd Milford Aquaculture Seminar (MAS). Bringing these different but complementary audiences together resulted in a meeting that combined many different aspects of fisheries restoration and aquaculture under one umbrella.Four hundred attendees including government representatives, research scientists, industry, and academia at both the university and vocational high school levels attended this event. The meeting commenced on Wednesday December 12th 2012, with over eighty people attending seven field trips to area aquaculture farms and research facilities. The formal program began on Thursday, December 13th with a plenary session including invited speakers Eric Schwabb, Acting Assistant Secretary for Conservation and Management at NOAA; Sebastian Belle, Executive Director of the Maine Aquaculture Association and Boze Hancock from the Nature Conservancy, who discussed the role of aquaculture in fisheries restoration. John Bullard, the Northeast Regional Administrator of NOAA Fisheries Service, addressed the group during the luncheon the following day. The technical papers and workshops presented were divided into 35 sessions over three days of the meeting and included topics such as the history of aquaculture, aquaculture hatchery innovations, siting and planning issues, risk management, aquaculture business management, ocean acidification, climate change, as well as aquaculture disease issues and potential remedies. Having persons present who have experienced problems and successes, along with those in manufacturing and government responsible for addressing concerns and sharing best practices, was invaluable. Discussions among this cross-section of persons who represent different aspects of aquaculture were as important as the well-presented and interesting formal papers and poster sessions. These discussions were facilitated by the many opportunities presented during the large trade show, reception, breaks, lunches, banquet and lobster bake held throughout the meeting.The importance of and need for aquaculture were made evident by all who were in attendance. We are grateful to the twenty four meeting sponsors and to all those who participated and made this such an important and memorable meeting.While oyster restoration efforts have been under way in the Chesapeake Bay for more than two decades, until recently, varying reporting methods and success criteria made it difficult to determine how much progress had been made. A goal to "Restore native oyster habitat and populations in 20 out of 35 to 40 candidate tributaries by 2025" was set in the 2010 strategy to implement the Chesapeake Bay Protection and Restoration Executive Order (signed by President Obama in 2009). This goal made it a priority for state and federal fishery managers, academics, and scientists working on oyster restoration to collaboratively define a "restored tributary" and a "restored reef" to enable them to track progress. A team of these people, led by NOAA staff, agreed on "oyster metrics" in 2011 (http//preview.tinyurl.com/8kmbdpm) that specify key metrics and target ranges for them, including tributary size, how to determine how much restorable bottom a tributary contains, how much of that restorable bottom needs to be restored, and the minimum oyster density and biomass in that restored bottom to count a tributary as restored. These new metrics enable experts to clearly see how oyster restoration efforts are working and use adaptive management to improve these efforts. These metrics serve as a tool to plan and evaluate oyster restoration consistently across the Chesapeake Bay, and the consensus-based framework used to develop them may have broader application to other restoration activities.In the past, oyster restoration in Maryland was performed primarily
In northeastern North America, Zygiella atrica often build their orb webs near the ocean. We analyzed individual field‐built Z. atrica webs to determine if organic low‐molecular‐mass solutes (LMM) in their sticky droplets showed any unusual features not previously seen in orb webs of other species living in less salty environments. While two of the three most abundant organic LMM (putrescine (butane‐1,4‐diamine) and GABamide (4‐aminobutanamide)) are already well‐known from webs of inland spiders, the third major LMM, β‐alaninamide (3‐aminopropanamide), a homolog of GABamide, has not been detected in sticky droplets from any other araneoid spiders (27 species). It remains to be established, however, whether or not use of β‐alaninamide is related to proximity to saltwater. We observed variability in organic LMM composition in Z. atrica webs that appeared to be influenced more by an undetermined factor associated with different collecting locations and/or collection dates than by different genders or instars. Shifts in composition when adult females were transferred from the field to the laboratory were also observed. Structural similarities and inverse correlations among β‐alaninamide, GABamide, and N‐acetylputrescine suggest that they may form a series of LMM fulfilling essentially the same, as yet unknown, role in the webs of those species in which they occur.
Foliose species of the Bangiales (Porphyra sensu lato) have a long history of study in the N Atlantic, but there are still regions, especially in the northern parts of the N Atlantic that need more attention. A molecular study using rbcL and cox1 sequences was undertaken to assess the diversity of foliose Bangiales species in Iceland and the Faroe Islands. Herbarium collections from the intertidal and subtidal of Iceland (summer and winter) and the Faroe Islands (all seasons) revealed a total of 13 species (11 common to both areas), which were referred to four of the genera recognized in a recent two-gene global phylogeny. Boreophyllum birdiae, Porphyra dioica, P. linearis, P. purpurea, P. umbilicalis, Pyropia 'leucosticta' A, Pyropia njordii Mols-Mortensen, J. Brodie & Neefus, sp. nov., Wildemania amplissima and W. miniata were common to both areas, while Pyropia thulaea and Wildemania abyssicola (Kjellman) A. Mols-Mortensen & J. Brodie, comb. nov. (Porphyra abyssicola Kjellman) were reported from Iceland but not from the Faroe Islands; Porphyra sp. FO and Pyropia elongata were reported from the Faroe Islands but not from Iceland. Boreophyllum birdiae is reported for the first time for Iceland and Porphyra sp. FO is reported for the first time for the Faroe Islands. Pyropia njordii is described from the Faroe Islands and is also recorded for Iceland, Greenland, New England, USA and Nova Scotia, Canada. A total of 25 foliose Bangiales species are now reported from the N Atlantic and these results demonstrate the importance of investigating as many areas as possible to reach a more complete understanding of species diversity and distribution.
Blackler first recorded Colpomenia peregrina in the Northwest Atlantic based on collections from Nova Scotia, Canada. Five decades later we found large quantities of C. peregrina in Maine, USA, even though it was absent during earlier floristic studies in this region. Thus, C. peregrina has undergone a rapid southern expansion along the Northwest Atlantic coast. While the causes of such an expansion are unknown, it could have a major effect on both shellfish cultivation and native seaweeds within New England because of competitive interactions and increased drag.
The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU ( rbc L) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia , and Wildemania . Four of the seven filamentous genera recognized in our analyses already have generic names ( Bangia , Dione , Minerva , and Pseudobangia ), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbc L sequence data should be obtained so that they can be assigned to the appropriate genus.
Distromatic foliose blades of the algal genus Ulva are notoriously difficult to identify due to their simple morphologies and few diagnostic characteristics that often exhibit intraspecific variation and interspecific overlap. Hence, species differentiation is difficult and diversity estimates are often inaccurate. Two major goals of this study were to assess the diversity of distromatic Ulva spp. in the Great Bay Estuarine System (GBES) of New Hampshire and Maine, USA, and to compare historical and present day records of these species. Molecular analysis (using ITS sequences) of field-collected specimens revealed four distinct taxa: Ulva lactuca, U. rigida, U. compressa, and U. pertusa. Prior to molecular screening, Ulva lactuca was the only distromatic Ulva species reported for the GBES. Ulva pertusa and the foliose form of U. compressa are newly recorded for the Northwest Atlantic, and the range of U. rigida has been extended. Molecular analysis of historical herbarium voucher specimens indicates that U. rigida, U. pertusa, and the foliose form of U. compressa have been present in the GBES since at least 1966, 1967, and 1972, respectively. The distromatic morphotype of U. compressa is found only in low salinity areas, which suggests that salinity may influence its morphological development. Molecular and morphological evaluations are critical if we are to distinguish between cryptic taxa, accurately assess biodiversity, and effectively monitor the spread of non-indigenous macroalgae.