Comparison of mesozooplankton production estimates from Saanich Inlet (British Columbia, Canada) using the chitobiase and biomass size spectra approaches

2020 ◽  
Vol 655 ◽  
pp. 59-75
Author(s):  
LE Kwong ◽  
KD Suchy ◽  
AR Sastri ◽  
JF Dower ◽  
EA Pakhomov

Zooplankton production estimates are necessary to understand the availability and transfer of energy to higher trophic levels in marine food webs. Methods have been developed to quantify zooplankton production; however, they are difficult to compare as they focus on single species, groups, stages, or size classes of zooplankton. We compared 2 methods for estimating crustacean production: the chitobiase method (based on a crustacean moulting enzyme), and 3 empirical growth rate models (Huntley-Lopez, Hirst-Lampitt, and Hirst-Bunker) applied to optically resolved mesozooplankton normalized biomass size spectra (NBSS). Mesozooplankton net samples were collected between March and August of 2010 and 2011 in Saanich Inlet (British Columbia, Canada) and analyzed in the laboratory using microscopy and a bench-top laser optical particle counter (lab-LOPC). Microscope and lab-LOPC estimates of abundance and biomass were in close agreement. Crustacean production estimates were highest using Huntley-Lopez (0.20-185.3 mg C m-3 d-1), followed by Hirst-Bunker (0 .01-18.3 mg C m-3 d-1), chitobiase (0.05-15.6 mg C m-3 d-1), and Hirst-Lampitt (0.03-14.3 mg C m-3 d-1). Hirst-Lampitt-, Hirst-Bunker-, and chitobiase-based estimates of crustacean production and trophic transfer efficiency (TTE) yielded similar patterns/magnitude, while the Huntley-Lopez model was more variable. Estimates showed stronger agreement in 2011 than in 2010, attributed to the shift from El Niño to La Niña conditions. We highlight similarities/differences associated with these techniques and suggest that Hirst-Bunker estimates of production and TTE are most consistent with chitobiase-based values.

Nature ◽  
1962 ◽  
Vol 194 (4823) ◽  
pp. 36-37 ◽  
Author(s):  
B. M. BARY ◽  
W. E. BARRACLOUGH ◽  
R. HERLINVEAUX

Zootaxa ◽  
2011 ◽  
Vol 2825 (1) ◽  
pp. 1 ◽  
Author(s):  
MICHEL ROUX ◽  
PHILIP LAMBERT

Two new species of deep-sea stalked crinoids belonging to the family Hyocrinidae were collected in the northeastern Pacific. The descriptions contain detailed information on character variations and ontogeny. The five specimens of Gephyrocrinus messingi n. sp. lived at depths ranging from 1,777 m to 2,110 m off British Columbia and California. This new species is the first record of the genus Gephyrocrinus in the Pacific Ocean, which was previously known from only a single species, G. grimaldii, from the northeastern Atlantic at the same depth range. The two species illustrate opposing phenotypes within the same genus. Fifty-eight specimens of the second new species, Ptilocrinus clarki n. sp., were dredged off British Columbia close to the type-locality of P. pinnatus, the type species of the genus Ptilocrinus, but at shallower depths ranging from 1,178 to 1,986 m. This exceptional collection provides significant data on intraspecific variation in the main morphological characters, especially arm pattern. The ontogeny of stalk articulations and the main traits of adoral plate differentiation are described in detail. A complementary investigation on P. pinnatus was conducted using specimens collected by the “Albatross” expedition at a depth of 2,906 m. Despite similarities in external morphology, tegmen and cover plates, the two ptilocrinid species display significant differences in pinnule architecture, aboral cup and stalk articulations. From comparison with Gephyrocrinus messingi n. sp. and Ptilocrinus clarki n. sp., G. grimaldii and P. pinnatus are interpreted as the result of heterochronic development by paedomorphy after ecological or geographic isolation. Pinnule architecture in the two new species suggests first steps in an evolutionary trend toward a rigid box which protects gonad inflation in the proximal part of the pinnule. These new data on Ptilocrinus and Gephyrocrinus create problems in the current taxonomy of the family Hyocrinidae. The main derived characters, especially in pinnule and arm pattern, are used to propose new hypotheses for hyocrinid phylogeny.


Zootaxa ◽  
2009 ◽  
Vol 2213 (1) ◽  
pp. 1-46 ◽  
Author(s):  
MATTHEW J. COLLOFF

The morphology of the genus Scapheremaeus Berlese, 1910 is reviewed and characters of taxonomic utility delineated. Based on the morphological review, some 13 species-groups are outlined based on major morphotypes. There are two main categories: i) species that have a complete circumdorsal scissure with plicate microsculpture on the circumnotogastral plate and strongly contrasting microsculpture (foveolae, ridges or tubercles) on the centrodorsal plate (plicate species-groups), and ii) species with the circumdorsal scissure complete, incomplete or absent but with little or no contrast in microsculpture between the central and lateral regions: typically both regions foveolate or reticulate (non- plicate species-groups). A catalogue of world species of Scapheremaeus is provided. Scapheremaeus petrophagus (Banks, 1906) is not a Scapheremaeus but belongs to an undetermined genus in the Ameronothroidea. Cymbaeremaeus cyclops Oudemans, 1915 is recombined to Scapheremaeus. Five new species are described (S. angusi sp. nov., S. cheloniella sp. nov., S. ewani sp. nov., S. lambieae sp. nov., and S. pulleni sp. nov.) from soil and litter habitats in semi-arid Mallee eucalypt vegetation at Bookmark Biosphere Reserve, South Australia. These are the first members of the genus Scapheremaeus to be described from Australia, though undescribed species have been recorded previously. All the new species are morphologically closely-related and belong to a single species-group: Carinatus.


1997 ◽  
Vol 54 (8) ◽  
pp. 1725-1735 ◽  
Author(s):  
D E Duplisea ◽  
S R Kerr ◽  
L M Dickie

Three parameters were derived from annual biomass size spectra constructed for a 22-year time series of demersal fish data for the entire Scotian Shelf: (i) total sampled biomass density, (ii) modal body weight, and (iii) the shape of the various biomass size spectra. Temporal variability of these parameters was compared among six species groups and between the species groups and their total. Species-group biomass varied more over the time series than did the total biomass, indicating the presence of a system factor. Conversely, modal body weight was as variable, and sometimes more variable, for the total than it was within species groups, indicating variability mainly at the species level. The shape of the biomass size spectrum showed annual differences in variability owing mainly to contributions of species groups. This variability was higher than variability in the combined species totals. We conclude that total biomass is limited at the combined species (systemwide) level because it depends on energy input to the system. Variability is greater at the species group (subsystem) level because the multiage species-group biomasses do not equally reflect a given energy limitation. Neither modal body weight nor the shape of the biomass spectrum is sensitive to the degree of taxonomic aggregation, suggesting that both measures are independent of energy input (primary production). We found no evidence of consistent species replacement trends on the shelfwide scale and conclude that diffuse replacement best describes species succession on the Scotian Shelf as a whole.


1985 ◽  
Vol 63 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Grant W. Hughes

A comparative analysis of the ecology of sympatrically occurring Pholis laeta and Pholis ornata was conducted in Saanich Inlet, British Columbia. Summer microhabitat use of eelgrass bed depths, intertidal habitat use, prey type, and characteristic location of prey taken differed in fish older than 1 year and may have facilitated the coexistence of these morphologically similar species. Prey sizes and activity patterns were similar between species. Winter segregation of the species during the breeding season may have reduced the possibility of hybridization. Competition for breeding habitats and differences in trophic apparatus may partly explain the observed patterns of resource use.


Zootaxa ◽  
2021 ◽  
Vol 4965 (3) ◽  
pp. 401-436
Author(s):  
ROBB BENNETT ◽  
CLAUDIA COPLEY ◽  
DARREN COPLEY

Species of North American Cybaeus L. Koch (Araneae: RTA clade: Cybaeidae) are common moist-forest spiders classified in Holarctic and Californian clades. Here, in the third paper in a planned series reviewing the six Californian clade species groups, we review the species of the consocius group. We recognize nine species: Cybaeus consocius Chamberlin & Ivie, C. hesper Chamberlin & Ivie, C. hummeli Bennett spec. nov., C. opulentus spec. nov., C. pan Bennett spec. nov., C. penedentatus Bennett, C. simplex Roth, C. ubicki Bennett spec. nov., and C. vulpinus Bennett. Eight of these species have restricted distributions in the central Sierra Nevada Mountains of eastern California, U.S.A (C. opulentus, C. pan spec. nov., and C. vulpinus) or the central coast of western California (C. consocius, C. hesper, C. hummeli spec. nov., C. penedentatus, and C. ubicki spec. nov.); a single species (C. simplex), is relatively widely distributed in western Oregon, U.S.A. Descriptions, illustrations, distribution maps, and an identification key are provided as well as a discussion of conservation issues of relevance to the group. 


Zootaxa ◽  
2009 ◽  
Vol 2259 (1) ◽  
pp. 1-159 ◽  
Author(s):  
GARY A. P. GIBSON

Spalangia Latreille and Playaspalangia Yoshimoto, the only two genera classified in Spalangiinae (Chalcidoidea: Pteromalidae) are revised for the New World. Thirty-one species of Spalangia and a single species of Playaspalangia, P. rothi Yoshimoto, are recognized from the New World. One further name, Spalangia tarsalis Brèthes, is treated as a nomen dubium. European species of Spalangia not yet known from the New World are also discussed and illustrated relative to regional species, but are not treated formally. The following new synonymies are proposed: Spalangia erythromera brachyceps Bouček under Spalangia erythromera Förster n. syn., Spalangia bakeri Kieffer under Spalangia chontalensis Cameron n. syn., and Spalangia lanaiensis Ashmead under Spalangia impunctata Howard n. syn. Spalangia simplex Perkins is newly recorded from the New World and the following 13 species are described as new: Spalangia alyxia n. sp., Spalangia flavicrus n. sp., Spalangia imitator n. sp., Spalangia innuba n. sp., Spalangia leiopleura n. sp., Spalangia masneri n. sp., Spalangia nigroides n. sp., Spalangia noyesi n. sp., Spalangia plaumanni n. sp., Spalangia rugosifrons n. sp., Spalangia stictocephala n. sp., Spalangia stictocyla n. sp., and Spalangia xanthoscapa n. sp. The 2 genera and the 32 regional species of Spalangiinae are keyed, described and illustrated, and regional hosts and distributions are summarized for each species. Distribution maps document the known range of each of the species in the New World. For purposes of comparison of morphologically similar species, 7 informal species groups are recognized in Spalangia to include 29 of the 31 New World species: the attae-group (S. attae Burks, S. rugosifrons, S. stictocyla and S. stictocephala), the cameroni-group (S. cameroni Perkins, S. longepetiolata Bouček and S. gemina Bouček), the drosophilae- group (S. bethyloides Bouček, S. drosophilae Ashmead, S. flavicrus, S. impunctata, S. innuba, S. leiopleura and S. plaumanni), the endius group (S. endius Walker and S. nigripes), the nigra-group (S. alyxia, S. chontalensis, S. masneri, S. nigra Latreille, S. nigroides and S. nigroaenea Curtis), the noyesi-group (S. noyesi and S. xanthoscapa), and the subpunctata-group (S. erythromera, S. fuscipes, S. haematobiae Ashmead, S. imitator and S. subpunctata Förster).


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