Invasive bryozoan alters interaction between a native grazer and its algal food

2013 ◽  
Vol 93 (5) ◽  
pp. 1393-1400 ◽  
Author(s):  
John M. O'Brien ◽  
Kira A. Krumhansl ◽  
Robert E. Scheibling
Keyword(s):  
Choice Experiment ◽  
Large Scale ◽  
Atlantic Coast ◽  
Grazing Rate ◽  
Choice Experiments ◽  
Saccharina Latissima ◽  
Membranipora Membranacea ◽  
Kelp Beds ◽  
Lacuna Vincta ◽  
Invasive Bryozoan

The epiphytic bryozoan Membranipora membranacea encrusts the surface of kelp blades, causing recurrent large-scale defoliation events in kelp beds off the Atlantic coast of Nova Scotia, Canada. The gastropod Lacuna vincta grazes kelp, creating perforations that weaken blade tissues and increase the fragmentation rate. We assess the interaction between M. membranacea and L. vincta by measuring the grazing rate of snails on bryozoan-encrusted and non-encrusted kelp (Saccharina latissima) in no-choice and choice experiments in the laboratory conducted in November and December 2010. There was no effect of diet on grazing rate in no-choice experiments. In choice experiments, however, L. vincta grazed significantly more non-encrusted than encrusted kelp (7.1 versus 1.1 mg snail−1 d−1), and grazing rate of non-encrusted kelp was almost twice that in the no-choice experiment (3.8 mg snail−1 d−1), indicating that snails may avoid colonies of M. membranacea on partially encrusted kelp blades. We found no effect of diet on growth, reproduction and survival of snails maintained for four weeks on encrusted or non-encrusted kelp. By concentrating grazing damage on non-encrusted areas of blades, L. vincta may act synergistically with M. membranacea to increase the likelihood of blade breakage and canopy loss. This indirect effect of the invasive bryozoan could augment its direct effect on the standing biomass of native kelp beds and detrital export to adjacent communities.

scholarly journals Phylogeography in an “oyster” shell provides first insights into the genetic structure of an extinct Ostrea edulis population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hayer ◽  
Dirk Brandis ◽  
Alexander Immel ◽  
Julian Susat ◽  
Montserrat Torres-Oliva ◽  
...  
Keyword(s):  
Large Scale ◽  
Wadden Sea ◽  
Atlantic Coast ◽  
Phylogenetic Reconstruction ◽  
Oyster Shell ◽  
Glacial Refugia ◽  
Late Nineteenth Century ◽  
Ostrea Edulis ◽  
Geographic Ranges ◽  
The North

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.

A Multi-proxy assessment of the impact of climate change on Late Holocene (ca 4500-3800 BP) Native American villages of the Georgia coast

2021 ◽  
Author(s):  
Carey James Garland ◽  
Victor D Thompson ◽  
Matthew C Sanger ◽  
Karen Y Smith ◽  
Fred T Andrus ◽  
...  
Keyword(s):  
Native American ◽  
Environmental Change ◽  
Large Scale ◽  
Atlantic Coast ◽  
Archaic Period ◽  
Late Archaic ◽  
Shell Ring ◽  
Shell Rings ◽  
Georgia Coast ◽  
The Impact

Circular shell rings along the Atlantic Coast of southeastern North America are the remnants of some of the earliest villages that emerged during the Late Archaic Period (5000 – 3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic Period (ca 3800 – 3000 BP). Here, we combine Bayesian chronological modeling with multiple environmental proxies to understand the nature and timing of environmental change associated with the emergence and abandonment of shell ring villages on Sapleo Island, Georgia. Our Bayesian models indicate that Native Americans occupied the three Sapelo shell rings at varying times with some generational overlap. By the end of the complex’s occupation, only Ring III was occupied before abandonment ca. 3845 BP. Ring III also consists of statistically smaller oysters ( Crassostrea virginica ) that people harvested from less saline estuaries compared to earlier occupations. These data, when integrated with recent tree ring analyses, show a clear pattern of environmental instability throughout the period in which the rings were occupied. We argue that as the climate became unstable around 4300 BP, aggregation at shell ring villages provided a way to effectively manage fisheries that are highly sensitive to environmental change. However, with the eventual collapse of oyster fisheries and subsequent rebound in environmental conditions ca. 3800 BP, people dispersed from shell rings, and shifted to non-marine subsistence economies and other types of settlements. This study provides the most comprehensive evidence correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period.

Anadromous Sturgeons: Habitats, Threats, and Management

2007 ◽  
Keyword(s):  
Large Scale ◽  
Atlantic Coast ◽  
The United States ◽  
Management Plan ◽  
Commercial Fishing ◽  
Atlantic Sturgeon ◽  
Coastal Fisheries ◽  
Number Of Factors ◽  
Acipenser Oxyrinchus ◽  
The U.S

<em>Abstract.</em>—Large-scale commercial fisheries for Atlantic sturgeon <em>Acipenser oxyrinchus</em> in the late 1880s eventually led to substantial reductions in the population size. The coastwide Atlantic sturgeon population of the United States has not recovered to the levels seen prior to the 1900s. A number of factors have contributed to the slow recovery or continued decline of Atlantic sturgeon populations, including continued commercial fishing and the targeting of females for caviar, bycatch in other fisheries, and changes in habitat due to dam construction and water quality degradation. The Atlantic States Marine Fisheries Commission (ASMFC) developed the first coastwide management plan for Atlantic sturgeon in 1990. In response to the shortcomings of that plan, the ASMFC applied new standards and the authority granted to it by the U.S. Congress to adopt a coastwide moratorium on all harvesting in 1998. A federal status review conducted in 1998 concluded that the continued existence of Atlantic sturgeon was not threatened given the situation at the time. Since then, monitoring programs have indicated varying levels of relative abundance in several water bodies along the Atlantic coast. The U.S. government is responsible for undertaking a status review to document any changes since the last review and determining whether those findings warrant a threatened or endangered listing for the species. The government’s findings may have far-reaching effects on many other Atlantic coastal fisheries.

Florida Inlets and Intertidal Biofouling Communities

2017 ◽  
Vol 51 (2) ◽  
pp. 7-21 ◽  
Author(s):  
Kevin B. Johnson ◽  
Jayden L. Roberts
Keyword(s):  
Atlantic Coast ◽  
Environmental Indicators ◽  
Rocky Intertidal ◽  
Drainage Basins ◽  
Bugula Neritina ◽  
Bare Rock ◽  
The North ◽  
Latitudinal Patterns ◽  
Invasive Bryozoan ◽  
Community Component

AbstractThis study reports on the identity and coverage of rocky intertidal species in the major inlets of Florida’s Atlantic coast. From north to south, these inlets are Fort George, St. Augustine, Ponce De Leon, Port Canaveral, Sebastian, Fort Pierce, Jupiter, Lake Worth, Boca Raton, Port Everglades, Baker’s Haulover, and Port of Miami. Dominant coverage in the southerly inlets included star corals (Siderastrea radians, 62% Port of Miami), ribbed barnacles (Tetraclita stalactifera, 18% Port Everglades), and zoanthid corals (Palythoa sp., 40% Baker’s Haulover). In the north, the community shifted and species absent in the south became common (e.g., eastern oysters Crassostrea virginica, 9% Fort George, 15% St. Augustine; the macroalga Enteromorpha lactuca, 10% Fort George, 17% Sebastian Inlet). The invasive bryozoan Bugula neritina was always present north of the Port of Miami and was a major community component north of Port Everglades (e.g., 27% Fort Pierce Inlet and 22% Ponce de Leon Inlet). Correlations between intertidal populations and environmental indicators included the oyster C. virginica with various sea surface temperature (SST) parameters (e.g., inverse correlations with max SST, R2 = 0.81, p = .038). Likewise, the coralline alga Pneophyllum fragile was correlated with various SST parameters (e.g., min SST, R2 = 0.51, p = .020). Bare rock and B. neritina both showed inverse correlations with the human population of inlet drainage basins (R2 = 0.28, p = .040 and R2 = 0.33, p = .026, respectively), the latter relationship an unexpected pattern for a notorious invader. These data show latitudinal patterns and provide baselines for future comparisons in the wake of projected climate change.

scholarly journals Supportive wind conditions influence offshore movements of Atlantic Coast Piping Plovers during fall migration

The Condor ◽  
2020 ◽  
Vol 122 (3) ◽  
Author(s):  
Pamela H Loring ◽  
James D McLaren ◽  
Holly F Goyert ◽  
Peter W C Paton
Keyword(s):  
North Carolina ◽  
New England ◽  
Large Scale ◽  
Atlantic Coast ◽  
Offshore Wind ◽  
Charadrius Melodus ◽  
Outer Continental Shelf ◽  
Southern New England ◽  
Piping Plovers ◽  
The U.S

Abstract In advance of large-scale development of offshore wind energy facilities throughout the U.S. Atlantic Outer Continental Shelf (OCS), information on the migratory ecology and routes of federally threatened Atlantic Coast Piping Plovers (Charadrius melodus melodus) is needed to conduct risk assessments pursuant to the Endangered Species Act. We tagged adult Piping Plovers (n = 150) with digitally coded VHF transmitters at 2 breeding areas within the southern New England region of the U.S. Atlantic coast from 2015 to 2017. We tracked their migratory departure flights using a regional automated telemetry network (n = 30 stations) extending across a portion of the U.S. Atlantic Bight region, a section of the U.S. Atlantic coast, and adjacent waters of the Atlantic Ocean extending from Cape Cod, Massachusetts, to Cape Hatteras, North Carolina. Most adults departed within a 10-day window from July 19 to July 29, migrated nocturnally, and over 75% of individuals departed within 3 hr of local sunset on evenings with supportive winds. Piping Plovers migrated offshore directly across the mid-Atlantic Bight, from breeding areas in southern New England to stopover sites spanning from New York to North Carolina, USA, over 800 km away. During offshore migratory flights, Piping Plovers flew at estimated mean speeds of 42 km hr−1 and altitudes of 288 m (range of model uncertainty: 36–1,031 m). This study provides new information on the timing, weather conditions, routes, and altitudes of Piping Plovers during fall migration. This information can be used in estimations of collision risk that could potentially result from the construction of offshore wind turbines under consideration across large areas of the U.S. Atlantic OCS.

scholarly journals Centennial-scale precipitation anomalies in the southern Altiplano (18° S) suggest an extratropical driver for the South American summer monsoon during the late Holocene

2019 ◽  
Vol 15 (5) ◽  
pp. 1845-1859 ◽  
Author(s):  
Ignacio A. Jara ◽  
Antonio Maldonado ◽  
Leticia González ◽  
Armand Hernández ◽  
Alberto Sáez ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Large Scale ◽  
Southern Oscillation ◽  
Atlantic Coast ◽  
Austral Summer ◽  
High Elevation ◽  
South American ◽  
Tropical Andes ◽  
The South ◽  
Precipitation Anomalies

Abstract. Modern precipitation anomalies in the Altiplano, South America, are closely linked to the strength of the South American summer monsoon (SASM), which is influenced by large-scale climate features sourced in the tropics such as the Intertropical Convergence Zone (ITCZ) and El Niño–Southern Oscillation (ENSO). However, the timing, direction, and spatial extent of precipitation changes prior to the instrumental period are still largely unknown, preventing a better understanding of the long-term drivers of the SASM and their effects over the Altiplano. Here we present a detailed pollen reconstruction from a sedimentary sequence covering the period between 4500 and 1000 cal yr BP in Lago Chungará (18∘ S; 4570 m a.s.l.), a high-elevation lake on the southwestern margin of the Altiplano where precipitation is delivered almost exclusively during the mature phase of the SASM over the austral summer. We distinguish three well-defined centennial-scale anomalies, with dry conditions between 4100–3300 and 1600–1000 cal yr BP and a conspicuous humid interval between 2400 and 1600 cal yr BP, which resulted from the weakening and strengthening of the SASM, respectively. Comparisons with other climate reconstructions from the Altiplano, the Atacama Desert, the tropical Andes, and the southwestern Atlantic coast reveal that – unlike modern climatological controls – past precipitation anomalies at Lago Chungará were largely decoupled from north–south shifts in the ITCZ and ENSO. A regionally coherent pattern of centennial-scale SASM variations and a significant latitudinal gradient in precipitation responses suggest the contribution of an extratropical moisture source for the SASM, with significant effects on precipitation variability in the southern Altiplano.

scholarly journals Latitudinal, seasonal and depth-dependent variation in growth, chemical composition and biofouling of cultivated Saccharina latissima (Phaeophyceae) along the Norwegian coast

2020 ◽  
Vol 32 (4) ◽  
pp. 2215-2232 ◽  
Author(s):  
Silje Forbord ◽  
Sanna Matsson ◽  
Guri E. Brodahl ◽  
Bodil A. Bluhm ◽  
Ole Jacob Broch ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Latitudinal Gradient ◽  
Biomass Yield ◽  
Saccharina Latissima ◽  
Seaweed Farming ◽  
Membranipora Membranacea ◽  
Salinity Levels ◽  
Biomass Yields ◽  
Tissue Nitrogen ◽  
Frond Length

Abstract The Norwegian coastline covers more than 10° in latitude and provides a range in abiotic and biotic conditions for seaweed farming. In this study, we compared the effects of cultivation depth and season on the increase in biomass (frond length and biomass yield), chemical composition (protein, tissue nitrogen, intracellular nitrate and ash content) and biofouling (total cover and species composition) of cultivated Saccharina latissima at nine locations along a latitudinal gradient from 58 to 69° N. The effects of light and temperature on frond length and biofouling were evaluated along with their relevance for selecting optimal cultivation sites. Growth was greater at 1–2 m than at 8–9 m depth and showed large differences among locations, mainly in relation to local salinity levels. Maximum frond lengths varied between 15 and 100 cm, and maximum biomass yields between 0.2 and 14 kg m−2. Timing of maximum frond length and biomass yield varied with latitude, peaking 5 and 8 weeks later in the northern location (69° N) than in the central (63° N) and southern (58° N) locations, respectively. The nitrogen-to-protein conversion factor (averaged across all locations and depths) was 3.8, while protein content varied from 22 to 109 mg g−1 DW, with seasonality and latitude having the largest effect. The onset of biofouling also followed a latitudinal pattern, with a delayed onset in northern locations and at freshwater-influenced sites. The dominant epibiont was the bryozoan Membranipora membranacea. Our results demonstrate the feasibility of S. latissima cultivation along a wide latitudinal gradient in North Atlantic waters and underscore the importance of careful site selection for seaweed aquaculture.

License Limitation Regulations: The South African System

1973 ◽  
Vol 30 (12) ◽  
pp. 2077-2084 ◽  
Author(s):  
L. P. D. Gertenbach
Keyword(s):  
South African ◽  
Large Scale ◽  
Scientific Evidence ◽  
Atlantic Coast ◽  
Second World War ◽  
World War ◽  
Conservation Policies ◽  
The Government ◽  
New Industry ◽  
Second World

The exploitation of pelagic shoal resources off South Africa’s west (Atlantic) coast began during the second world war, with large-scale expansion beginning in 1947–49. At the end of the forties, the Government lacked the scientific evidence to formulate effective conservation policies, and pending the outcome of the research programs it deemed it advisable to put a brake on the expansion of these fisheries.An obvious measure was a ceiling on the annual catches. But this would not necessarily have prevented further influx into the fishing or the processing phases of the industry. As part of an economy-wide practice to require licenses for various kinds of operations, these were required for all fishing boats and factories. The Government decided in 1949 to refuse the issue of licenses for additional fish-processing factories and to limit the number and capacity to those already in operation or under construction.In 1953 the fishermen, aware of the limitation on the outlets (factory intakes) for their catches, and the continued influx of outsiders into the flourishing fishing side, willingly agreed to the freezing of the number and hold capacity of vessels fishing for pilchards and maasbankers. After the enactment by parliament of the necessary enabling laws, regulations were issued to establish a Pilchard/Maasbanker Boat Limitation Committee consisting of government, factory, and fishermen representatives to apply the controls over the number of boats, their hold capacity and the allocation of this fleet to the various factories.Adjustments, including some increases in the capacity of the fleet, were made from time to time to cope with changing conditions in the resource.A serious weakening in the control system occurred when fishing and processing licenses were granted to operators of fishmeal factory ships.The results of the limitation of entry into the fishing phase and the processing phases include several significant trends, among which are a smaller number of boats, larger-size boats with more powerful engines and equipment, and increased factory-ownership of boats. The factories introduced stickwater plants and other processes to increase the yield of meal from the available tonnage of raw fish.Although the industry has experienced difficult periods, it nevertheless seems, broadly viewed, that through the policy of restricting entry at the early stages of the new industry, it acquired sufficient resilience to cope not only with the ups but also the downs. It appears doubtful that "overcrowded" fishing and processing sectors would have had sufficient resilience to face fluctuating catches and fishmeal prices.

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