A climatology and time series for dissolved nitrate in the Gulf of Maine region

2014 ◽  
Vol 103 ◽  
pp. 223-237 ◽  
Author(s):  
N.D. Rebuck ◽  
D.W. Townsend
Keyword(s):  
Time Series ◽  
Gulf Of Maine

scholarly journals Time-series metabarcoding analysis of zooplankton diversity of the NW Atlantic continental shelf

2019 ◽  
Vol 76 (4) ◽  
pp. 1162-1176 ◽  
Author(s):  
Ann Bucklin ◽  
Heidi D Yeh ◽  
Jennifer M Questel ◽  
David E Richardson ◽  
Bo Reese ◽  
...  
Keyword(s):  
Time Series ◽  
Gulf Of Maine ◽  
Diversity Index ◽  
Hypervariable Region ◽  
Detailed Examination ◽  
Science Center ◽  
Ecosystem Monitoring ◽  
Fisheries Science ◽  
Ocean Ecosystem ◽  
Taxonomic Groups

Abstract Biodiversity of zooplankton is central to the functioning of ocean ecosystems, yet morphological taxonomic analysis requires teams of experts and detailed examination of many samples. Metabarcoding (DNA sequencing of short amplified regions of one or a few genes from environmental samples) is a powerful tool for analysis of the composition and diversity of natural communities. The 18S rRNA V9 hypervariable region was sequenced for 26 zooplankton samples collected from the Gulf of Maine, Georges Bank, and Mid-Atlantic Bight during ecosystem monitoring surveys by the U.S. Northeast Fisheries Science Center during 2002–2012. A total of 7 648 033 sequences and 22 072 operational taxonomic units (OTUs) were identified and classified into 28 taxonomic groups of plankton. Comparative analysis of molecular (V9 sequence numbers) and morphological (abundance counts) focused on seven taxonomic groups and revealed similar patterns of variation among years and regions. Sequence numbers and abundance counts showed positive correlation for all groups, with significant correlations (p < 0.05) for Calanoida, Gastropoda, and Chaetognatha. Shannon diversity index values calculated using sequence numbers and abundance counts showed highly significant correlation (r = 0.625; p < 0.001) across all regions during 2002–2012. This study demonstrates the potential of metabarcoding for time-series analysis of zooplankton biodiversity, ocean ecosystem assessment, and fisheries management.

Time-series measurements of atmospheric and oceanic CO2 and O2 in the Western Gulf of Maine

OCEANS 2008 ◽  
2008 ◽  
Author(s):  
S. Shellito ◽  
J. Irish ◽  
D. Vandemark ◽  
S. Maenner ◽  
N. Lawerence-Slavas ◽  
...  
Keyword(s):  
Time Series ◽  
Gulf Of Maine

scholarly journals Air-Sea CO<sub>2</sub> fluxes on the Scotian Shelf: seasonal to multi-annual variability

2010 ◽  
Vol 7 (11) ◽  
pp. 3851-3867 ◽  
Author(s):  
E. H. Shadwick ◽  
H. Thomas ◽  
A. Comeau ◽  
S. E. Craig ◽  
C. W. Hunt ◽  
...  
Keyword(s):  
Time Series ◽  
Surface Waters ◽  
Gulf Of Maine ◽  
Co2 Flux ◽  
Sea Surface ◽  
Co2 Fluxes ◽  
Resolution Time ◽  
Scotian Shelf ◽  
Shelf Region ◽  
Annual Scale

Abstract. We develop an algorithm to compute pCO2 in the Scotian Shelf region (NW Atlantic) from satellite-based estimates of chlorophyll-a concentration, sea-surface temperature, and observed wind speed. This algorithm is based on a high-resolution time-series of pCO2 observations from an autonomous mooring. At the mooring location (44.3° N and 63.3° W), the surface waters act as a source of CO2 to the atmosphere over the annual scale, with an outgassing of −1.1 mol C m−2 yr−1 in 2007/2008. A hindcast of air-sea CO2 fluxes from 1999 to 2008 reveals significant variability both spatially and from year to year. Over the decade, the shelf-wide annual air-sea fluxes range from an outgassing of −1.70 mol C m−2 yr−1 in 2002, to −0.02 mol C m−2 yr−1 in 2006. There is a gradient in the air-sea CO2 flux between the northeastern Cabot Strait region which acts as a net sink of CO2 with an annual uptake of 0.50 to 1.00 mol C m−2 yr−1, and the southwestern Gulf of Maine region which acts as a source ranging from −0.80 to −2.50 mol C m−2 yr−1. There is a decline, or a negative trend, in the air-sea pCO2 gradient of 23 μatm over the decade, which can be explained by a cooling of 1.3 °C over the same period. Regional conditions govern spatial, seasonal, and interannual variability on the Scotian Shelf, while multi-annual trends appear to be influenced by larger scale processes.

scholarly journals Potential growth of pelagic juvenile cod in relation to the 1978–2006 winter–spring zooplankton on the Northeast US continental shelf

2015 ◽  
Vol 72 (9) ◽  
pp. 2549-2568 ◽  
Author(s):  
R. G. Lough ◽  
T. Kristiansen
Keyword(s):  
Time Series ◽  
New England ◽  
Gulf Of Maine ◽  
Climatic Conditions ◽  
Calanus Finmarchicus ◽  
Georges Bank ◽  
Potential Growth ◽  
Lower Growth ◽  
Centropages Typicus ◽  
Pelagic Juvenile

Abstract Environmental conditions during the pelagic juvenile cod period determine their fitness to survive settlement as demersal juveniles (0-group) and recruitment. This study examines the potential growth of pelagic juvenile cod in five areas of the New England Shelf based on time series of zooplankton and ocean temperature from surveys. An individual-based model was used to estimate the temporal variation in growth of juvenile cod at each survey station based on available prey of appropriate sized copepods of Calanus finmarchicus, Pseudocalanus spp., Centropages typicus, and Centropages hamatus. Mean juvenile cod growth was low (1–7% d−1) during January–February and March–April time series across all areas, Gulf of Maine (GOM), Eastern Georges Bank, Western Georges Bank, southern New England to Middle Atlantic Bight (MAB). Growth increased significantly in May–June with the seasonal increase in copepod density and temperature generally from South to North. The 1990–1999 warm years had the highest growth of 12–14% d−1 compared with the cooler 2000–2006 years and colder 1978–1989 years of similarly lower growth of 8–11% d−1. Growth in the MAB stayed the same 13% d−1 as in 1990–1999, whereas GOM growth decreased significantly to ∼6% d−1. High prey densities during May–June 1990–1999 for Georges Bank and GOM, followed by a strong decrease in 2000–2006 may explain the decrease in growth during the same periods. While all four copepod species contributed to potential growth, C. typicus, a more southern species, could be the more important prey for juveniles in the coastal areas during all months in contrast to Pseudocalanus spp. for the larvae. Centropages typicus also is the most adaptable and likely species able to expand and thrive under warmer climatic conditions, which could be of significance to future recruitment. Age-1 recruitment for Georges Bank cod was found to be related to juvenile growth.

scholarly journals Multiyear variability of phytoplankton abundance in the Gulf of Maine

2011 ◽  
Vol 68 (9) ◽  
pp. 1833-1841 ◽  
Author(s):  
Joseph Kane
Keyword(s):  
Time Series ◽  
Gulf Of Maine ◽  
Late Summer ◽  
Environmental Variable ◽  
Calanus Finmarchicus ◽  
Phytoplankton Abundance ◽  
Low Salinity ◽  
The North ◽  
The Common ◽  
The North Atlantic Oscillation

Abstract Kane, J. 2011. Multiyear variability of phytoplankton abundance in the Gulf of Maine. – ICES Journal of Marine Science, 68: 1833–1841. Significant interannual changes in phytoplankton abundance were identified in the Continuous Plankton Recorder time-series collected in the Gulf of Maine from 1961 to 2008. Abundance levels of nearly all the common taxa began to increase in 1990 and remained elevated through 2001. During that period, total numbers were above average throughout the year, with an unusual bloom in late summer. Multivariate analysis of abundance identified three consecutive multiyear periods of varying abundance levels: low to average from 1961 to 1989, above average or very high from 1990 to 2001, and below average thereafter, through 2008. Phytoplankton abundance patterns were closely aligned to the rising trends displayed by several of the common zooplankton taxa. The North Atlantic Oscillation was the only environmental variable examined that showed some association with time-series abundance trends of plankton. The index was primarily positive in the 1990s, which would favour the propagation of warm, nutrient-rich slope water into the region. Perhaps the increased influx of this water, along with feedback enrichment from abundant zooplankton stocks and reduced top-down control by the relative scarcity of the dominant copepod Calanus finmarchicus, combined with a low salinity to make the 1990s a unique decade for plankton change in the Gulf of Maine.

scholarly journals Alexandrium fundyense cysts in the Gulf of Maine: Long-term time series of abundance and distribution, and linkages to past and future blooms

2014 ◽  
Vol 103 ◽  
pp. 6-26 ◽  
Author(s):  
Donald M. Anderson ◽  
Bruce A. Keafer ◽  
Judith L. Kleindinst ◽  
Dennis J. McGillicuddy ◽  
Jennifer L. Martin ◽  
...  
Keyword(s):  
Time Series ◽  
Gulf Of Maine ◽  
Alexandrium Fundyense ◽  
Abundance And Distribution

scholarly journals Coherent trends in contiguous survey time-series of major ecological and commercial fish species in the Gulf of Maine ecosystem

2009 ◽  
Vol 67 (1) ◽  
pp. 26-40 ◽  
Author(s):  
Janet A. Nye ◽  
Alida Bundy ◽  
Nancy Shackell ◽  
Kevin D. Friedland ◽  
Jason S. Link
Keyword(s):  
United States ◽  
Time Series ◽  
Fish Species ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Ecological Factors ◽  
The United States ◽  
Common Species ◽  
Total Biomass ◽  
Commercial Fish

AbstractNye, J. A., Bundy, A., Shackell, N., Friedland, K. D., and Link, J. S. 2010. Coherent trends in contiguous survey time-series of major ecological and commercial fish species in the Gulf of Maine ecosystem. – ICES Journal of Marine Science, 67: 26–40. Fish are often delineated into distinct population or stock units that reflect human institutional borders more than ecological factors. In the Northwest Atlantic, there are many species in the broader Gulf of Maine area (GOMA), yet the area is surveyed and managed for the most part in the south by the United States and in the north by Canada. Biomass time-series of 19 representative fish species and total biomass from 7 different surveys conducted by the United States and Canada in the GOMA are compared. All species showed coherent trends in relative biomass across at least two survey time-series, and in many species a single trend could describe all time-series trends accurately. For instance, Canadian and the US time-series of Atlantic cod, Atlantic herring, haddock, thorny skate, and goosefish had comparable trends. Conversely, species such as longhorn sculpin and spiny dogfish showed differing survey time-series trends and asynchronous event timing, suggesting that their population dynamics differ spatially. Collectively, the results demonstrate the value of comparing time-series for common species from contiguous ecosystems and elucidate the relative importance of environmental and fishing factors on each species.

scholarly journals Interdecadal variability in the Gulf of Maine zooplankton community, with potential impacts on fish recruitment

2005 ◽  
Vol 62 (7) ◽  
pp. 1511-1523 ◽  
Author(s):  
Andrew J. Pershing ◽  
Charles H. Greene ◽  
Jack W. Jossi ◽  
Loretta O'Brien ◽  
Jon K.T. Brodziak ◽  
...  
Keyword(s):  
Time Series ◽  
Large Scale ◽  
Gulf Of Maine ◽  
Principal Component ◽  
Trophic Levels ◽  
Interdecadal Variability ◽  
Calanus Finmarchicus ◽  
Rapid Decline ◽  
Zooplankton Abundance ◽  
The Impact

Abstract We used principal component analysis (PCA) to explore interannual changes in a time-series lasting more than 40 years of zooplankton abundance from NOAA's Continuous Plankton Recorder (CPR) survey. This analysis identified a complex of taxa, including Centropages typicus, Oithona spp., Pseudocalanus spp., and Metridia lucens that followed a common pattern of interdecadal variability characterized by a dramatic increase in these taxa around 1990, followed by a rapid decline in 2002. All of these taxa showed a large proportional increase in winter abundance between the 1980s and 1990s. These changes could be driven by increased primary productivity during winter, caused by a large-scale freshening of the Northwest Atlantic Shelf. In addition to the “community shift” mode, the analysis found a strong mode of interannual variability attributed to previously described changes in the abundance of late-stage Calanus finmarchicus. To explore the impact of these modes on higher trophic levels, we correlated the zooplankton modes with recruitment time-series from 12 fish stocks from the Gulf of Maine region. Several significant correlations were found, suggesting that the changes in the zooplankton modes may reflect broad changes in the Gulf of Maine ecosystem.

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