23 results on '"Scofield, Anne E."'
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2. Could quagga mussels impact offshore benthic community and surface sediment-bound nutrients in the Laurentian Great Lakes?
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Eifert, Rae-Ann, Burlakova, Lyubov E., Karatayev, Alexander Y., Daniel, Susan E., Scofield, Anne E., and Hinchey, Elizabeth K.
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- 2023
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3. Intra-lake trends and inter-lake comparisons of Mysis diluviana life history variables and their relationships to food limitation
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Holda, Toby J., Watkins, James M., Scofield, Anne E., Pothoven, Steven A., Warner, David M., O'Brien, Timothy P., Bowen, Kelly L., Currie, Warren J.S., Jude, David J., Boynton, Patrick V., and Rudstam, Lars G.
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- 2023
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4. Size spectra analysis of a decade of Laurentian Great Lakes data
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Evans, Thomas M., Feiner, Zachary S., Rudstam, Lars G., Mason, Doran M., Watkins, James M., Reavie, Euan D., Scofield, Anne E., Burlakova, Lyubov E., Karatayev, Alexander Y., and Sprules, W. Gary
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Great Lakes (North America) -- Environmental aspects ,Plankton -- Environmental aspects -- Physiological aspects -- Forecasts and trends ,Market trend/market analysis ,Earth sciences - Abstract
Size spectra analysis (SSA) is used to detect changes in food webs by simplifying complex community structures through abundance-versus-biomass considerations. We applied SSA to 10 years (2006-2015) of data on Great Lakes organisms ranging in size from picoplankton to macrozooplankton. Summer pelagic size spectra slopes were near the theoretical value of -1.0, but spring slopes were steeper, reflecting seasonal differences in abundance of small and large individuals. Pelagic size spectra slopes were relatively stable over the time period we examined. Height (the predicted number of organisms at the spectra midpoint) varied among lakes and was slightly higher in summer than spring in more productive basins. Including benthic data led to shallower slopes when combined with pelagic data, suggesting benthic organisms may increase food web efficiency; height was less affected by benthic data. Benthic data are not routinely included in SSA, but our results suggest they affect slopes and therefore SSA-based predictions of fish abundance. The ability of SSA to track changes in trophic energy transfer makes it a valuable ecosystem monitoring tool. L'analyse des spectres de taille (AST) est utilisee pour detecter des changements dans les reseaux trophiques en simplifiant la structure de communautes complexes sur la base de considerations concernant l'abondance et la biomasse. Nous avons applique l'AST a 10 annees (2006-2015) de donnees sur des organismes des Grands Lacs de tailles allant du picoplancton au macrozooplancton. Les pentes des spectres de taille pelagiques estivaux s'approchent de la valeur theorique de -1,0, mais les pentes des spectres printaniers sont plus fortes, refletant des variations saisonnieres de l'abondance des petits et grands individus. Les pentes des spectres de taille pelagiques sont relativement stables durant la periode etudiee. La hauteur (le nombre predit d'organismes au point median du spectre) varie d'un lac a l'autre et est legerement plus grande en ete qu'au printemps dans les bassins plus productifs. L'inclusion de donnees benthiques produit des pentes plus faibles quand elles sont combinees aux donnees pelagiques, ce qui donne a penser que les organismes benthiques pourraient accroitre l'efficacite du reseau trophique; l'incidence des donnees benthiques sur la hauteur est moins importante. Des donnees benthiques ne sont pas systematiquement incluses dans les AST, mais nos resultats indiqueraient qu'elles ont une incidence sur les pentes et donc sur les predictions de l'abondance des poissons issues de l'AST. La capacite de l'AST de faire ressortir les variations des transferts energetiques trophiques en fait un bon outil de surveillance des ecosystemes. [Traduit par la Redaction], Introduction Understanding and predicting ecosystem productivity requires knowledge about the current state of the ecosystem and how it influences production of different organisms. However, ecosystem modeling is challenging because food [...]
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- 2022
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5. Consequences of changing water clarity on the fish and fisheries of the Laurentian Great Lakes
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Bunnell, David B., Ludsin, Stuart A., Knight, Roger L., Rudstam, Lars G., Williamson, Craig E., Hook, Tomas O., Collingsworth, Paris D., Lesht, Barry M., Barbiero, Richard P., Scofield, Anne E., Rutherford, Edward S., Gaynor, Layne, Vanderploeg, Henry A., and Koops, Marten A.
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Great Lakes (North America) -- Environmental aspects ,Fishes -- Environmental aspects ,Fisheries -- Environmental aspects ,Fish industry -- Environmental aspects ,Water turbidity -- Environmental aspects ,Earth sciences - Abstract
Human-driven environmental change underlies recent changes in water clarity in many of the world's great lakes, yet our understanding of the consequences of these changes on the fish and fisheries they support remains incomplete. Herein, we offer a framework to organize current knowledge, guide future research, and help fisheries managers understand how water clarity can affect their valued populations. Emphasizing Laurentian Great Lakes findings where possible, we describe how changing water clarity can directly affect fish populations and communities by altering exposure to ultraviolet radiation, foraging success, predation risk, reproductive behavior, or territoriality. We also discuss how changing water clarity can affect fisheries harvest and assessment through effects on fisher behavior and sampling efficiency (i.e., catchability). Finally, we discuss whether changing water clarity can affect understudied aspects of fishery performance, including economic and community benefits. We conclude by identifying generalized predictions and discuss their implications for priority research questions for the Laurentian Great Lakes. Even though the motivation for this work was regional, the breadth of the review and generality of the framework are readily transferable to other freshwater and marine habitats. Si des modifications de l'environnement causees par les humains sous-tendent les changements recents de la clarte de l'eau dans bon nombre des grands lacs de la planete, notre comprehension des consequences de ces changements sur les poissons et les peches qu'ils soutiennent demeure incomplete. Nous presentons un cadre pour organiser les connaissances actuelles, orienter la recherche future et aider les gestionnaires des peches a comprendre l'incidence possible de la clarte de l'eau sur les populations qu'ils gerent. En mettant l'accent, dans la mesure du possible, sur des constatations relatives aux Grands Lacs laurentiens, nous decrivons l'incidence directe que peuvent avoir les variations de la clarte de l'eau sur les populations et communautes de poissons en modifiant l'exposition au rayonnement ultraviolet, le succes d'approvisionnement, le risque de predation, le comportement de reproduction ou la territorialite. Nous abordons egalement l'incidence que peuvent avoir les modifications de la clarte de l'eau sur les prises et revaluation des peches par le biais d'effets sur le comportement des pecheurs et l'efficacite d'echantillonnage (c.-a-d., la capturabilite). Enfin, nous tentons d'etablir si les modifications de la clarte de l'eau peuvent avoir une incidence sur des aspects sous-etudies de la performance des peches, y compris les avantages economiques et pour les collectivites. Nous concluons en formulant des predictions generales et discutons des questions de recherche prioritaires qu'elles font ressortir pour les Grands Lacs laurentiens. Meme si l'intention a l'origine du present article etait regionale, la portee de la synthese et le caractere general du cadre font qu'ils peuvent etre transposes aisement a d'autres habitats marins et d'eau douce. [Traduit par la Redaction], Introduction Although scientists have increasingly documented changing water clarity in freshwater ecosystems worldwide, we do not fully understand its effects on aquatic food webs and the fisheries that they support. [...]
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- 2021
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6. Deep chlorophyll maxima across a trophic state gradient : A case study in the Laurentian Great Lakes
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Scofield, Anne E., Watkins, James M., Osantowski, Eric, and Rudstam, Lars G.
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- 2020
7. Are Harmful Algal Blooms Increasing in the Great Lakes?
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Bosse, Karl R., Fahnenstiel, Gary L., Buelo, Cal D., Pawlowski, Matthew B., Scofield, Anne E., Hinchey, Elizabeth K., and Sayers, Michael J.
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MODIS (Spectroradiometer) ,NORMALIZED difference vegetation index ,ALGAL blooms ,REMOTE sensing ,IMAGE sensors - Abstract
This study used satellite remote sensing to investigate trends in harmful algal blooms (HABs) over the last 21 years, focusing on four regions within the Laurentian Great Lakes: western Lake Erie, Green Bay, Saginaw Bay, and western Lake Superior. HABs in the water column were identified from remote sensing-derived chlorophyll concentrations, and surface HAB scums were classified based on the Normalized Difference Vegetation Index (NDVI) band ratio index. Using imagery from the Moderate Resolution Imaging Spectroradiometer sensor on the Aqua satellite (MODIS-Aqua) from 2002 to 2022, we generated daily estimates of the HAB and surface scum extents for each region, which were then averaged to generate mean annual extents. We observed a significant decline in the Saginaw Bay mean annual HAB extents over the 21-year study period. Otherwise, no significant changes were observed over this period in any region for either the HAB or surface scum mean annual extents, thus suggesting that HABs are not increasing in the Great Lakes. Despite the lack of increasing trends, the blooms are still recurring annually and causing a negative impact on the nearby communities; thus, we believe that it is crucial to continue studying Great Lakes HABs to monitor the impact of current and future abatement strategies. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Heterogeneity in zooplankton distributions and vertical migrations: Application of a laser optical plankton counter in offshore Lake Michigan
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Scofield, Anne E., Watkins, James M., and Rudstam, Lars G.
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- 2020
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9. Feeding ecology of Limnocalanus macrurus in the Laurentian Great Lakes
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Nasworthy, Kayden C., Scofield, Anne E., and Rudstam, Lars G.
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- 2020
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10. The deep chlorophyll layer in Lake Ontario: extent, mechanisms of formation, and abiotic predictors
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Scofield, Anne E., Watkins, James M., Weidel, Brian C., Luckey, Frederick J., and Rudstam, Lars G.
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- 2017
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11. Lake-wide measurements of primary productivity in Lake Erie.
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Lesht, Barry M., Scofield, Anne E., and Bockwoldt, Katelyn A.
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CARBON fixation , *PHOTOSYNTHETIC rates , *PRODUCTIVITY accounting , *TIME series analysis , *SOLAR radiation - Abstract
Few lake-wide, seasonal primary production measurements have been made in Lake Erie. None more recent than 1997 have been reported in the literature. In 2019 we used 13C uptake to measure production at 11 stations across the lake during three surveys in May, July, and September and at four of these stations during two additional surveys in April and August. Samples were collected at two depths (2 m and 6 m) and incubated on deck using eight levels of irradiance. We fit the resultant photosynthesis-irradiance curves with models that included the initial slope at low light levels, the maximum photosynthesis rate at light saturation, and when warranted, the negative slope at high irradiance. During May, there was little variation in chlorophyll-normalized volumetric productivity with sample depth, and productivity generally was higher nearshore and in the western basin than it was offshore. The distinction between nearshore and offshore stations was less pronounced in July, but nearshore productivity was higher than offshore in September. Using the photosynthesis data from all five surveys, chlorophyll concentration profiles, and estimated clear-sky solar insolation, we calculated time series of vertically integrated daily production at a western basin station, two central basin stations, and an eastern basin station. Central basin production was highest during August, estimated to be 748 mg C m-2 d-1 and 779 mg C m-2 d-1 at our two stations. Production peaked in July in the western basin (510 mg C m-2 d-1) and September in the eastern basin (421 mg C m-2 d-1). Whole-lake seasonal areal phytoplankton photosynthesis was estimated as 1.661E6 tonnes, about half of estimates made in the 1990s using 14C methods. These results inform our understanding of spatial-temporal trends in Lake Erie productivity and highlight the need for continued measurements of Lake Erie primary production. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Cyclops sibiricus Lindberg 1949
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Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E., and Rudstam, Lars G.
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Arthropoda ,Cyclops sibiricus ,Hexanauplia ,Animalia ,Cyclops ,Biodiversity ,Cyclopoida ,Taxonomy ,Cyclopidae - Abstract
Cyclops sibiricus Lindberg, 1949 Synonymy: Cyclops strenuus sibiricus Lindberg (1949): 87 −90, fig. 1. Cyclops canadensis Einsle (1988): 2146 −2149, fig. 1. Material examined: 1 female dissected and slide mounted, 1 female, collected from the St. Marys River, Sault Ste. Marie, Michigan, USA (46.49853N,- 84.32590W)on May 15,1972,initially reported as C.strenuus in Selgeby (1975). 4 females dissected and slide mounted, 7 females, collected from the St. Marys River, Neebish Island, Michigan, USA (46.33691 N, - 84.20122 W) on May 3 and May 24, 1995, initially reported as C. strenuus in Hudson et al. (1998). Females: Body large, robust and cyclopiform. Prosome longer than urosome (Table 1), cephalothorax longer then wide. Rostrum fairly pronounced. Antennule (A1) consisting of 17 segments (Fig. 1a), not extending beyond the cephalothorax. A small convex row of spinules present on the proximal margin of the A1 first segment. Pitting on surface of A1 first segment apparently absent (Fig. 1b). Setation present on A1 segments 1−9, 11−12, 14−17. Aesthetascs present on A1 segments 12, 16, and 17. Aesthetasc on A1 segment 12 extending to the middle of segment 14 (Fig. 1c). A1 segments 15−17 with finely textured hyaline membrane (Fig. 1d). Antenna (A2) 4-segmented with 3 setae on the basipodite including exopodite seta and 1,9, 7 setae on the successive (endopodal)segments.A2 exopodite seta reaching beyond the distal margin of the endopod and lightly ornamented with plumose setules which decrease in length distally. Caudal surface of A2 basipodite (Fig. 2a) ornamented with 4−6 broad based spinules descending in height from the lateral to distal margin, a single oblique row of 5−6 short thin spinules at position B (Hołyńska et al. 2003), 7−9 long thin spinules longitudinally at position A, and flanked laterally by a field of tiny spinules numbering approximately 12 at position C. Labrum (La) and Mandible (Md) not observed in detail. Maxillular (Mxl) palp proximalmost seta (Fig. 2b) ornamented only with tiny spinules distally, setae of the lateral lobe ornamented likewise. Surface of Mxl palp either ornamented with exceedingly tiny spinules or apparently bare (Fig. 2b). Maxilla (Mx) not observed in detail. Maxilliped (Mxp) syncoxopodite armed with 3 plumose setae, basipodite with 2 plumose setae, endopodite 1 with 1 plumose seta, endopodite 2 with 1 plumose and 2 bare setae. Mxp syncoxopodite frontal surface ornamented with a long membranous element (Hołyńska & Dahms 2004) with somewhat club shaped distal terminus (Fig. 2c) and a transverse row of approximately 10 small spinules. Ornamentation present on the frontal surface of successive mxp segments in the form of thin hair-like spinules with the exception of endopodite 2. Spine formula of swimming legs 1−4 (P1−P4) third exopodite 3, 4, 3, 3. Full spine and setal formula of P1−P4 shown in Table 2 following Sewell (1949). Ornamentation of swimming legs is as follows. P1 intercoxal sclerite (coupler) and coxopodite unornamented. P1 coxopodite setae densely ornamented with long setules. P1 basipodite armed with a row of long spinules on the frontal surface between insertion of exopodite and endopodite (Fig. 2d). P1 medial margin of basipodite haired and medial spine of basipodite with proximal margin bare and distal margin sparely armed with setules (Fig. 2d). P2 coupler unornamented, coxopodite seta armed as in P1, coxopodite ornamented with spinules at position B and hairs at position F (Einsle, 1996a). P2 medial margin of basipodite haired. P3 ornamented as in P2 except coupler caudal surface ornamented with horizontal row of long hairs. P4 coupler ornamented as in P3, coxopodite ornamented with spinules at positions, A, B, C, D, and E (Fig. 2e). P4 coxopodite setae short, not extending beyond medial margin of basipodite and sparsely ornamented with setules (Fig. 2f; Table 1). P4 medial margin of basipodite unhaired. P4 endopodite 3 longer then wide with outer terminal spine relatively short (Table 1). P5 basal segment with spinules present near insertion of lateral seta. P5 distal segment with long apical seta (Table 1) and stout subapical spine. Spinules present lateral to the insertion of the apical seta and at the insertion of the subapical spine. Genital double-somite wider then long at widest point (Table 1), surface pitting discrete if present. Posterior margins of proceeding 2 urosomites crenulate. Posterior margin of anal somite ornamented with fine spinules. Anal operculum unornamented. Caudal rami more than five times longer than wide (Table 1) with inner margins weakly haired.Tiny spinules ornament the insertions of lateral and terminal external (Einsle 1996a)caudal seta (S4) (Hołyńska et al. 2003). Terminal median internal caudal setae (S2) relatively long, nearly equal in length to the urosome and more than twice as long as caudal rami (Table 1). Additional morphometry of caudal setae included in Table 1., Published as part of Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E. & Rudstam, Lars G., 2022, Reevaluation of the genus Cyclops Müller, 1776 (Cyclopoida: Cyclopidae) in the Laurentian Great Lakes basin: first report of the Palearctic species Cyclops divergens Lindberg, 1936 from Lake Erie and documentation of Cyclops sibiricus Lindberg, 1949 in the St. Marys River, pp. 183-195 in Zootaxa 5182 (2) on pages 185-186, DOI: 10.11646/zootaxa.5182.2.5, http://zenodo.org/record/7049624, {"references":["Lindberg, K. (1949) Contribution a l'etude de quelques Cyclopides (Crustaces copepodes) du groupe strenuus provenant principalement du Nord de l'Eurasie. Arkiv fur Zoologi, 1, 87 - 99.","Einsle, U. K. (1988) Cyclops canadensis n. sp. and Cyclops scutifer Sars, 1863 (Crustacea: Copepoda) from northern Canada. Canadian Journal of Zoology, 66, 2146 - 2149. https: // doi. org / 10.1139 / z 88 - 319","Selgeby, J. H. (1975) Life histories and abundance of crustacean zooplankton in the outlet of Lake Superior, 1971 - 1972. Journal of the Fisheries Research Board of Canada, 32, 461 - 470. https: // doi. org / 10.1139 / f 75 - 056","Hudson, P. L., Reid, J. W., Lesko, L. T. & Selgeby, J. H. (1998) Cyclopoid and harpacticoid copepods of the Laurentian Great Lakes. Ohio Biological Survey Bulletin, Columbus, 1 - 50 pp.","Holynska, M., Mirabdullayev, I. M., Reid, J. W. & Ueda, H. (2003) Copepoda: Cyclopoida: Genera Mesocyclops and Thermocyclops, In: Dumont, H. J. F., Ueda, H. & Reid, J. W. (Ed.), Guides to the Identification of the Microinvertebrates of the Continental Waters of the World Vol. 20. Backhuys, Leiden, 1 - 318 pp.","Holynska, M. & Dahms H. (2004) New diagnostic microcharacters of the cephalothoracic appendages in Cyclops O. F. Muller, 1776 (Crustacea, Copepoda, Cyclopoida). Zoosystema, 26, 175 - 198.","Sewell, R. B. S. (1949) The littoral and semi-parasitic Cyclopoida, Monstrilloida and Notodelphyoida. Scientific Report John Murray Expedition, 1933 - 34, 9, 17 - 199.","Einsle, U. K. (1996 a) Copepoda: Cyclopoida: Genera Cyclops, Megacyclops, Acanthocyclops, In: Dumont, H. J. F. (Ed.), Guides to the Identification of the Microinvertebrates of the Continental Waters of the World Vol. 10. SPB Academic Publishing, New York City, 1 - 83 pp."]}
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- 2022
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13. Cyclops divergens Lindberg 1936
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Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E., and Rudstam, Lars G.
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Cyclops divergens ,Arthropoda ,Hexanauplia ,Animalia ,Cyclops ,Biodiversity ,Cyclopoida ,Taxonomy ,Cyclopidae - Abstract
Cyclops divergens Lindberg, 1936 Synonymy: Cyclops strenuus divergens Lindberg (1936): 3 −5, figs. 3−7. Cyclops rubens divulsus Lindberg (1956): 112 −113. Cyclops singularis Einsle (1996b): 170, 172−176, figs. 2−6. Material examined: 1 female dissected and slide mounted, collected from U.S. EPA GLNPO monitoring station ER58, Lake Erie, Ohio, USA (41.67853 N, - 82.93182 W) on April 1, 2013 (planktonic abundance of C. strenuus in Barbiero et al. (2019). 1 male dissected and slide mounted, collected from Maumee Bay, Lake Erie, Ohio, USA (41.70217 N, - 83.35375 W) on April 17, 2014, initially reported as C. strenuus in Hudson & Lesko (2003). 1 male dissected and slide mounted, collected from U.S. EPA GLNPO monitoring station ER61, Lake Erie, Ontario, Canada (41.94755 N, - 83.04310 W) on April 20, 2019 (planktonic abundance of C. sibiricus (Table 1), robust and cyclopiform. Prosome longer than urosome (Table 1) and cephalothorax longer then wide. Rostrum small and fairly discrete. A1 consisting of 17 segments (Fig. 3a) and extending beyond the cephalothorax. A1 first segment strongly pitted (Fig. 3b) as described in Krajíček et al. (2016) and ornamented with a small convex row of spinules. Setation present on A1 segments 1−9, 11−12, 14−17. Aesthetascs present on A1 segments 12, 16, and 17. Aesthetasc on A1 segment 12 extending to the midpoint of segment 14 (Fig. 3c). A1 segments 15−17 with finely textured hyaline membrane (Fig. 3d). A2 4-segmented with 3 setae on the basipodite including exopodite seta and 1, 9, 7 setae on the successive (endopodal) segments. A2 exopodite seta reaching beyond the distal margin of the endopodite and strongly ornamented with large spinules. Caudal surface of A2 basipodite (Fig. 4a) ornamented with 6 large spinules of similar height from the lateral to distal margin, an oblique row of 5 stout spinules and a small convex row of 4 short broad based spinules at position B (Hołyńska et al. 2003), a longitudinal row of approximately 9 spinules at position A, and flanked by a small field of approximately 12 tiny spinules at position C. In general, ornamentation of this appendage more robust in appearance then that of C. sibiricus. La with hair on caudal surface restricted to small parallel patches. Md not observed in detail. Mxl palp proximalmost seta ornamented with plumose setules in the proximal third and all 3 setae of the lateral lobe ornamented with only tiny spinules distally. Two large conspicuous spinules present on the surface of one maxillular palp and inconspicuous on the other palp. Mx not observed in detail. Mxp syncoxopodite armed with 3 plumose setae, basipodite with 2 plumose setae, endopodite 1 with 1 plumose seta, endopodite 2 with 1 plumose and 2 bare setae. Mxp sycoxopodite with relatively short membranous element with prominent hook at distal terminus (Fig. 4b) as in Hołyńska & Dahms (2004) and ornamented with a transverse row of small spinules on the distal third as described in Krajíček et al. (2016). Ornamentation present on the frontal surface of successive mxp segments in the form of thin hair-like spinules except endopodite 2. Spine formula of P1−P4 identical to C. sibiricus (Table 2). Ornamentation of swimming legs as follows. P1 coupler and coxopodite unornamented. P1 coxopodite setae strongly ornamented with long setules. P1 medial margin of basipodite haired, basipodite frontal surface with a row of long spinules between the insertion of exopodite and endopodite (Fig. 4c). Medial spine of basipodite setulation heteronomous with long setules proximally and abruptly decreasing in length distally (Fig. 4c). P2 and P3 ornamented likewise as follows. Coupler unornamented. Coxopodite ornamented with spinules at position B and hairs at F (Einsle 1996a). Coxopodite setae strongly ornamented with long setules. P4 coupler caudal surface ornamented with a proximally placed horizontal row of long hairs. P4 coxopodite ornamented (Fig. 4d) with spinules at positions A, C, D, and E. P4 coxopodite setae long extending beyond the distal terminus of the basipodite medial margin (Fig. 4e; Table 1) and medial margin of basipodite unhaired. P4 coxopodite setae with proximal third sparsely armed with long setules and distal 2 thirds densely armed with long setules. P4 endopodite 3 longer than wide and outer terminal spine relatively long (Table 1). P5 basal segment lacking ornamentation, P5 distal segment as in C. sibiricus. P5 apical seta long (Table 1) and ornamented with plumose setules distally. Genital double-somite wider then long at widest point (Table 1) and surface strongly pitted. Posterior margins of proceeding 2 urosomites crenulate. Posterior margin of anal somite ornamented with fine spinules. Anal operculum unornamented. Caudal rami more than five times longer than wide (Table 1) with inner margins haired. Tiny spinules present at the insertions of lateral caudal seta and S4 (Hołyńska et al. 2003). S2 shorter than urosome and longer than caudal rami (Table 1). Males: Body as in female, with total body length shorter than female (Table 1). Prosome longer than urosome, slightly more so than female (Table 1) and cephalothorax longer than wide. A1 geniculate (Fig. 5a), consisting of 17 segments variously modified in length and width in comparison to female. A1 first and second segment strongly pitted, pitting rapidly declines in subsequent segments. Setation present on all segments. A1 first segment with 3 aesthetascs, 2 placed proximally and 1 distally. Singular aesthetascs present on A1 segments 4, 9, 13, 16, and 17. A single pectenate seta present on A1 segments 11 and 12. A2 armature as in female. A2 caudal surface ornamentation as in female with additional spinulation at position C (approximately 20 spinules). La as in female. Md gnathobase armed with 10−12 jagged, and more or less triangular teeth of similar length but variable width and 2 setae, 1 pectenate and one bare. Md palp with 2 long plumose setae and 1 short bare seta. Mxl palp proximalmost seta ornamented with plumose setules in the proximal third (Fig. 5b) and tiny spinules in the distal two thirds. Setae of the mxl palp lateral lobe lacking setules, ornamented only with tiny spinules. Large spinules present on the surface of mxl palp (Fig. 5b), 3 spinules apparent on both palps in 2014 specimen, 4 spinules apparent on one palp and 3 on the other in 2019 specimen. Mx not observed in detail. Mxp armed and ornamented as in female. P1−P4 armature as in female (Table 2), P1−P4 ornamentation as in female with the exception of the P4 basipodite medial margin being partly to fully haired and long hairs on caudal surface of P4 coupler notably more abundant (Fig. 5c). P4 endopodite 3 more elongate than in female (Table 1). P5 as in female. Rudimentary leg 6 (P6) consisting of 3 setae, 1 long plumose seta, 1 short plumose seta, and 1 short pectenate seta, with tiny spinules present at the insertion of each seta. Urosome 5-segmented and sparsely pitted. Ornamentation of posterior margin of urosomites, anal somite, and anal operculum as in female. Morphometry of caudal rami and caudal setae similar to that of female (Table 1). Genetic Sequencing The C. divergens CV copepodite specimen (Sample ID: ZOOPS _0581) collected from Lake Erie produced a successful COI-5P genetic sequence (http://www.boldsystems.org/index.php/Public_RecordView?processid=ZOO PS581-20). The specimen was assigned to BIN BOLD: ACL 6037 (dx.doi.org/10.5883/ BOLD: ACL 6037) which is populated with 20 COI-5P sequences of Cyclops specimens from continental Europe in the Barcode of Life Data system (Ratnasingham & Hebert 2007). The Lake Erie C. divergens COI-5P sequence was 99.4% similar to a specimen (COPCLAD456) collected from Norway (Falkenhaug & Hobaek unpublished), 99.2% similar to a specimen (MK 329340) collected from Poland (Hołyńska & Wyngaard 2019), and 97.7−98.0% similar to three specimens (KP 772955, KP772957, KP 772958) collected from Czechia (Krajíček et al. 2016). Mean distance between the Lake Erie C.divergens CV copepodite specimen and the above mentioned publicly available C. divergens COI-5P sequences from Europe was 1.60%. The sequenced specimen is e-vouchered in the BOLD collection at the University of Guelph, all other Lake Erie and St. Marys River Cyclops specimens are archived at the Cornell Biological Field Station., Published as part of Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E. & Rudstam, Lars G., 2022, Reevaluation of the genus Cyclops Müller, 1776 (Cyclopoida: Cyclopidae) in the Laurentian Great Lakes basin: first report of the Palearctic species Cyclops divergens Lindberg, 1936 from Lake Erie and documentation of Cyclops sibiricus Lindberg, 1949 in the St. Marys River, pp. 183-195 in Zootaxa 5182 (2) on pages 187-190, DOI: 10.11646/zootaxa.5182.2.5, http://zenodo.org/record/7049624, {"references":["Lindberg, K. (1936) Notes sur des Cyclopides (Crustaces Copepodes) de l'Iran. Bulletin du Musee royal d'Histoire naturelle de Belgique, 12, 1 - 26.","Lindberg, K. (1956) Courtes diagnoses de quelques membres nouveaux ou peu connus du genre Cyclops S. Str. Bolletino della Societa Entomologica Italiana, 86, 112 - 117.","Einsle, U. K. (1996 b) Cyclops heberti n. sp. and Cyclops singularis n. sp., two new species within the genus Cyclops (\" strenuussubgroup \") (Crust. Copepoda) from ephemeral ponds in southern Germany. Hydrobiologia, 319, 167 - 177. https: // doi. org / 10.1007 / BF 00013729","Barbiero, R. P., Rudstam, L. G., Watkins, J. M. & Lesht, B. M. (2019) A cross-lake comparison of crustacean zooplankton communities in the Laurentian Great Lakes, 1997 - 2016. Journal of Great Lakes Research 45, 672 - 690. https: // doi. org / 10.1016 / j. jglr. 2019.03.012","Hudson, P. L. & Lesko, L. T. (2003) Free-living and parasitic copepods of the Laurentian Great Lakes: Keys and details on individual species. Available from: http: // www. glsc. usgs. gov / greatlakescopepods / (Accessed 25 May 2022)","Holynska, M., Mirabdullayev, I. M., Reid, J. W. & Ueda, H. (2003) Copepoda: Cyclopoida: Genera Mesocyclops and Thermocyclops, In: Dumont, H. J. F., Ueda, H. & Reid, J. W. (Ed.), Guides to the Identification of the Microinvertebrates of the Continental Waters of the World Vol. 20. Backhuys, Leiden, 1 - 318 pp.","Holynska, M. & Dahms H. (2004) New diagnostic microcharacters of the cephalothoracic appendages in Cyclops O. F. Muller, 1776 (Crustacea, Copepoda, Cyclopoida). Zoosystema, 26, 175 - 198.","Einsle, U. K. (1996 a) Copepoda: Cyclopoida: Genera Cyclops, Megacyclops, Acanthocyclops, In: Dumont, H. J. F. (Ed.), Guides to the Identification of the Microinvertebrates of the Continental Waters of the World Vol. 10. SPB Academic Publishing, New York City, 1 - 83 pp.","Ratnasingham, S. & Hebert, P. D. N. (2007) BOLD: The Barcode of Life Data System (www. barcodinglife. org). Molecular Ecology Notes, 7, 355 - 364. https: // doi. org / 10.1111 / j. 1471 - 8286.2007.01678. x","Holynska, M. & Wyngaard, G. A. (2019) Towards a phylogeny of Cyclops (Copepoda). Zoologica Scripta, 1 - 23. https: // doi. org / 10.1111 / zsc. 12342"]}
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- 2022
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14. Cyclops Muller 1776
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Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E., and Rudstam, Lars G.
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Arthropoda ,Hexanauplia ,Animalia ,Cyclops ,Biodiversity ,Cyclopoida ,Taxonomy ,Cyclopidae - Abstract
Key to Cyclops species of the Laurentian Great Lakes: 1a. Long setules present on proximalmost seta of mxl palp (Fig. 5b)................................................ 2 1b. Long setules absent on proximalmost seta of mxl palp (Fig. 2b)................................................. 3 2. A1 extending beyond cephalothorax (female) and A1 first segment densely pitted (Fig. 3b), surface of mxl palp ornamented with large spinules (Fig. 5b), mxp syncoxopodite with short membranous element featuring prominent distal hook (Fig. 4b) and transverse row of small spinules, P1 basipodite medial spine with heteronomous setulation (Fig. 4c), P3 coupler unornamented, P4 coupler ornamented with horizontal row of long hairs (Fig. 5c), P4 coxopodite ornamented with spinules at positions A, C, D, and E (Fig. 4d), P4 coxopodite setae extending beyond medial margin of the basipodite (Fig. 4e), P5 basal segment lacking ornamentation................................................................. C. divergens Lindberg, 1936 3a. P4 coxopodite setae unmodified (Fig. 2f).................................................................. 4 3b. P4 coxopodite setae proximally swollen................................................................ 5 4. A1not extending beyond cephalothorax (female) andA1 first segment lacking pits (Fig. 1b), surface of the mxl palp unornamented or ornamented with only tiny spinules (Fig. 2b), mxp syncoxopodite with long membranous element featuring somewhat club shaped distal terminus (Fig. 2c) and transverse row of small spinules, P1 basipodite medial spine proximal margin bare (Fig. 2d), P3 and P4 coupler ornamented with horizontal row of long hairs, P4 coxopodite ornamented with spinules at positions A, B, C, D, and E (Fig. 2e), P4 coxopodite setae not extending beyond medial margin of the basipodite (Fig. 2f), P5 basal segment ornamented with spinules near insertion of lateral seta.................................... C. sibiricus Lindberg, 1949 5. A1 extending beyond cephalothorax (female) and A1 first segment lacking pits, surface of the mxl palp ornamented with small spinules, mxp syncoxopodite with short membranous element lacking distal hook or club and with oblique row of long spinules, P4 coupler unornamented, P4 coxopodite ornamented with spinules at positions A, B, C, D, and occasionally F, P4 coxopodite setae extending beyond medial margin of the basipodite, P5 basal segment unornamented............ C. scutifer Sars, 1863, Published as part of Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick L., Watkins, James M., Scofield, Anne E. & Rudstam, Lars G., 2022, Reevaluation of the genus Cyclops Müller, 1776 (Cyclopoida: Cyclopidae) in the Laurentian Great Lakes basin: first report of the Palearctic species Cyclops divergens Lindberg, 1936 from Lake Erie and documentation of Cyclops sibiricus Lindberg, 1949 in the St. Marys River, pp. 183-195 in Zootaxa 5182 (2) on pages 191-192, DOI: 10.11646/zootaxa.5182.2.5, http://zenodo.org/record/7049624, {"references":["Lindberg, K. (1936) Notes sur des Cyclopides (Crustaces Copepodes) de l'Iran. Bulletin du Musee royal d'Histoire naturelle de Belgique, 12, 1 - 26.","Lindberg, K. (1949) Contribution a l'etude de quelques Cyclopides (Crustaces copepodes) du groupe strenuus provenant principalement du Nord de l'Eurasie. Arkiv fur Zoologi, 1, 87 - 99.","Sars, G. O. (1863) Oversigt af de indenlandske Ferskvandcopepoder. Forhandlinger i Videnskabs-Selskabet i Christiana, 1862, 212 - 262."]}
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- 2022
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15. Reevaluation of the genus Cyclops Müller, 1776 (Cyclopoida: Cyclopidae) in the Laurentian Great Lakes basin: first report of the Palearctic species Cyclops divergens Lindberg, 1936 from Lake Erie and documentation of Cyclops sibiricus Lindberg, 1949 in the St. Marys River
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CONNOLLY, JOSEPH K., primary, MARSHALL, CHRISTOPHER C., additional, HUDSON, PATRICK L., additional, WATKINS, JAMES M., additional, SCOFIELD, ANNE E., additional, and RUDSTAM, LARS G., additional
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- 2022
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16. Foreword: Stressors and successes, Lake Ontario CSMI intensive year 2018
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Watkins, James M., primary, Rudstam, Lars G., additional, Karatayev, Alexander Y., additional, Currie, Warren J.S., additional, Scofield, Anne E., additional, and Hollenhorst, Thomas P., additional
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- 2022
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17. Seasonal habitat use indicates that depth may mediate the potential for invasive round goby impacts in inland lakes
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Andres, Kara J., primary, Sethi, Suresh Andrew, additional, Duskey, Elizabeth, additional, Lepak, Jesse M., additional, Rice, Aaron N., additional, Estabrook, Bobbi J., additional, Fitzpatrick, Kimberly B., additional, George, Ellen, additional, Marcy‐Quay, Benjamin, additional, Paufve, Matthew R., additional, Perkins, Kelly, additional, and Scofield, Anne E., additional
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- 2020
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18. Reevaluation of the genus Cyclops in the Great Lakes: report of the exotic species Cyclops divergens from Lake Erie.
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Connolly, Joseph K., Marshall, Christopher C., Hudson, Patrick, Watkins, James M., Scofield, Anne E., and Rudstam, Lars G.
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CYCLOPS scutifer - Abstract
Large cyclopoid copepods of the genus Cyclops are seldom collected in the Laurentian Great Lakes, with only Cyclops scutifer and Cyclops strenuus reported from the region. Rare reports of the species C. strenuus date back to 1972 within the Great Lakes basin. The first specimens reported as C. strenuus were collected from the St. Marys River, and additional specimens have been collected from western Lake Erie since 2013. We examined all available archived materials of C. strenuus from the Great Lakes and determined that specimens from the two localities belong to two separate species, neither of which refer to C. strenuus. Archived specimens collected from the St. Marys River in 1972 and 1995 were reidentified as Cyclops sibiricus, a Holarctic species known from Siberia, Russian Federation, Alaska, USA, and northern regions of Canada. The occurrences of C. sibiricus from the St. Marys River extend the known distribution of the species southward some 1,688 km in the Nearctic region. Cyclops specimens collected from the western basin of Lake Erie in 2013, 2014, and 2019 were identified as the Palearctic species Cyclops divergens using both conventional taxonomy and genetic barcoding. C. divergens is known from localities across much of Europe and eastward into Central Asia. The occurrences of the species from western Lake Erie constitute the first detection of C. divergens in the Great Lakes and the Nearctic region. Therefore, we expect C. strenuus does not occur in the Great Lakes basin and is likely restricted to the Palearctic region. [ABSTRACT FROM AUTHOR]
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- 2023
19. Finescale vertical distribution of Zooplankton in offshore Lake Ontario in 2018.
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Watkins, James M., Scofield, Anne E., Hollenhorst, Tom, Miller, Sam, and Rudstam, Lars G.
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ZOOPLANKTON - Abstract
Zooplankton in Lake Ontario cover a broad range of size and taxonomic groups that exhibit a diversity of life history strategies and environmental preferences. Vertical gradients of light and temperature are particularly important controls on distribution. Monitoring based on traditional net sampling provide only a coarse assessment of overall biomass and community composition. However, a finer scale understanding of the vertical variation of zooplankton is important for comparisons to the distribution of phytoplankton and planktivorous fish. During 2018, a Triaxus vehicle and V-fin equipped with a laser optical plankton counter (LOPC) were towed several times along a western and eastern offshore transect in Lake Ontario, undulating from 5 to 60 m depth along a 10 km path. These continuous transects supplemented a traditional lakewide net-based zooplankton survey. Zooplankton respond to both horizontal gradients such as thermal bar fronts in spring as well as vertical gradients such as summer stratification and deep chlorophyll maxima (DCM). Deep zooplankton layers initially align closely with the DCM, but persist into the fall despite weaker stratification and the complete dissipation of the DCM. These layers were consistently represented by deep calanoid copepods, while other taxa were limited to the warmer epilimnion. [ABSTRACT FROM AUTHOR]
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- 2023
20. Consistent patterns in δ13C and δ15N of multiple trophic levels across the Laurentian Great Lakes.
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Scofield, Anne E., Hook, Tomas O., Bunnell, David B., Fisk, Aaron, Hoffman, Joel C., Johnson, Timothy B., Weidel, Brian C., Bootsma, Harvey A., Heuvel, Cecilia E., Krauss, Richard, McNaught, Andrew Scott, Nawrocki, Brent, Rennie, Michael, Turschak, Benjamin, Vinson, Mark, Wegher, Marissa, and Collingsworth, Paris D.
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STABLE isotope tracers ,FOOD chains - Abstract
Stable isotope ratios of nitrogen (δ
15 N) and carbon (δ13 C) are valuable tools for studying food web structure, but broad-scale variations in baseline δ15 N and δ13 C are not well-understood for freshwaters. We use the Great Lakes as a case study to test for variation in isotopic ratios in lakes that exhibit gradients in residence time, watershed characteristics, and trophic state. We used a nested ANOVA to investigate differences in δ13 C and δ15 N of organisms of multiple trophic levels (zooplankton, benthos, rainbow smelt, and lake trout) across lakes and seasons, accounting for within-lake variation due to region and year. There were significant effects of lake on baseline values of δ13 C and δ15 N; patterns were generally consistent with expectations, with more oligotrophic lakes (Superior) being relatively depleted and more mesotrophic (Ontario) to eutrophic (Erie) lakes being enriched in both δ13 C and δ15 N. Season was a significant factor for δ13 C in all taxa except benthos and for δ15 N in zooplankton and rainbow smelt. Zooplankton and benthos δ15 N values were highly variable, but this variation was dampened in fish, as expected due to integration of prey items over time. Post-hoc analysis of δ13 C and δ15 N versus lakewide average chlorophyll, residence time, and watershed characteristics indicate that these properties are correlated with stable isotopes values. This study suggests that baseline isotopes ratios in large lakes may be predictable based on lake and watershed characteristics, as has been demonstrated for some marine and smaller freshwater systems. [ABSTRACT FROM AUTHOR]- Published
- 2023
21. Trophic dynamics of fishes in the Great Lakes: a cross-lake comparison using stable isotopes data.
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Eglite, Elvita, Scofield, Anne E., Hook, Tomas O., and Collingsworth, Paris D.
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ISOTOPES - Abstract
Stable isotope ratios of nitrogen (δ
15 N) and carbon (δ13 C) are valuable tools for identifying basal energy sources for fish production and describing trophic complexity, but cross-lake comparisons are often limited by the challenges associated with standardizing study design and isotopic baselines. Using studies conducted in collaboration with the bi-national Cooperative Science and Monitoring Initiative, as well as other research efforts across the Great Lakes, we assembled δ15 N and δ13 C data for zooplankton and fish muscle tissue across all Great Lakes from 2002 to 2018. We aimed to detect differences in food web structures by estimating trophic positions (TP) and the ratio of benthic to pelagic δ13 C contributions for planktivorous Rainbow Smelt (Osmerus mordaX) and piscivorous Lake Trout (Salvelinus namaycush). To account for variable baselines in the lower food web, we used averaged bulk zooplankton δ15 N values by lake, month, year. Despite high variation in the zooplankton, we identified a robust pattern in TP across lakes for both species. Consistent with predator-prey interactions, mean TPs of Lake Trout (4.1-5.9) were greater than Rainbow Smelt (3.1-4.6) in all lakes. TPs were lower in Superior, Huron and Michigan, and greater in Ontario and Erie. The proportion of benthic/pelagic contributions to fish diets also differed among lakes, with Lake Huron having the highest benthic reliance. Overall, TPs increased with the lake productivity and suggest that both food web complexity and resource use by these fish species differs across lakes. [ABSTRACT FROM AUTHOR]- Published
- 2023
22. Trends in particulate nutrient concentrations and seston stoichiometry of the Laurentian Great Lakes.
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Doody, Erica, Scofield, Anne E., and Pawlowski, Matthew
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STOICHIOMETRY - Abstract
Offshore particulate matter is typically planktonic in origin; changes in concentrations and elemental ratios can reflect surrounding ecological conditions and aid in assessing ecosystem health. The EPA's Great Lakes National Program Office has collected particulate nutrient data in both spring and summer from all five of the Laurentian Great Lakes since the late 1990s. Here, we present a cross-lake comparison of temporal trends in particulate phosphorus (PP), particulate nitrogen (PN), particulate organic carbon (POC), total suspended solids (TSS), and seston stoichiometry (N:P) from 1997 - 2019. Significant spring trends over the full time series include increased PP in Lake Superior, increased PN in central and eastern Lake Erie, decreased PP, PN, POC and TSS in Lake Huron, and decreased PP and TSS in southern Lake Michigan. The only significant trends in summer data were declines in epilimnion PP and TSS in Lake Michigan. After over a decade of general declines, PN concentrations across most lakes started increasing in 2012, with a significant break point in that year for lakes Superior, Huron, Michigan, and Ontario. Particulate N:P has changed in recent years, indicating possible nutrient deficiency in the lower food web, and the recent changes may hint at declining seston nutritional quality. We also compare particulate nutrient temporal patterns to the timing of significant ecological changes in the Great Lakes, including the expansion of dreissenid mussel populations, declines in the spring phytoplankton bloom, and changes to the zooplankton community. [ABSTRACT FROM AUTHOR]
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- 2023
23. Insights into scattering layer identity using dual frequency acoustics in the Great Lakes.
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Blair, Hannah, Rudstam, Lars G., Nasworthy, Kayden C., Watkins, James M., Scofield, Anne E., Evans, Thomas M., Sethi, Suresh A., Warner, David M., Yule, Daniel L., and Esselman, Peter C.
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BIOMASS ,ZOOPLANKTON ,SOUND waves - Abstract
Acoustic backscattering strength (Sv) depends not only on biomass but also on the size of the animals insonified. The length dependence is related to the relative length of the sound wave and the animals and is highly dependent on the frequency of sound used. This relationship is non-linear, and smaller organisms have substantially lower acoustics backscattering at lower frequencies (=i.e., shorter wavelengths) compared to larger organisms. Marine acousticians use the difference in backscattering at different frequencies to infer the identity of the organisms in the scattering layers. The taxonomically less complex zooplankton community in Great Lakes should lend itself even better to this approach than the highly diverse oceans. Here we present examples from several data sets to explore the ability of Sv differencing to identify and separate fish, mysids and larger zooplankton in the Great Lakes. Acoustic returns from both ships and unmanned vehicles were compared with data from Optical Plankton Counters and net tows. Sv differencing using 120 and 430 kHz data provided distinct signatures for zooplankton, mysid, and fish layers. Increased future use of multifrequency unmanned acoustic data collection systems will increase our ability to predict distribution and migrations of different zooplankton groups. [ABSTRACT FROM AUTHOR]
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- 2023
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