Erroneous Counts Research Articles

Possibilities and limitations of platelet counting methods

Currently, the use of hematological analyzers makes it possible to quickly and accurately count the number of platelets in the vast majority of blood samples. In some cases, the automatic determination of this indicator may be incorrect, due to the limitations of the methods used. Monitoring the results of automatic platelet count is necessary when obtaining pathological values and is carried out by microscopic examination of a peripheral blood smear. The article describes the methods and limitations of automatic determination of the number of platelets, possible causes of erroneous counting and ways to correct the result. Morphological descriptions of the most common artifacts that affect the correct definition of this indicator are presented. Modern methodological approaches to solving the problem of correct platelet counting in EDTA-dependent pseudothrombocytopenia are highlighted.

Data investigation of installed and output power densities of onshore and offshore wind turbines worldwide

Differing estimates have emerged about how much land or water area is used by existing wind farms and how much power can be obtained from that area. Whereas, no single unique method exists to define wind farm spacing area, the spacing area (thus installed and output power densities) of a wind farm can be determined in a way to meet specific logical criteria, This study proposes a new, intuitive, data based, automatized method of estimating spacing areas occupied by existing onshore and offshore wind farms worldwide. The method eliminates the erroneous counting of space outside of wind farm boundaries, space between clusters of turbines, and overlapping space that results when assuming a large fixed area around each turbine. At least one of three types of extra space has incorrectly been included in all calculations of wind farm areas to date. Unlike most previous methods, this method also ensures that the addition of a wind turbine to a farm increases the overall required spacing area of the farm. The study then uses data from over 1600 operating wind turbines in 16 onshore and 7 offshore wind farms in 13 countries across 5 continents during the period 2016–2018 to quantify installed and output power densities of these farms. Finally, it compares results with estimates from other studies. Results indicate that the mean (range) installed and output power densities of onshore wind farms in Europe are 19.8 (6.2–46.9) MW/km2 and 6.64 (2.3–8.2) W/m2, respectively; of onshore wind farms outside of Europe are similarly 20.5 (16.5–48) MW/km2 and 6.84 (4.81–11.2) W/m2, respectively; and of offshore wind farms in Europe are 7.2 (3.3–20.2) MW/km2 and 2.94 (1.15–6.32) W/m2, respectively. The mean capacity factors in each case are thus 33.5%, 33.4%, and 40.8%, respectively. These results indicate substantially higher installed and output power densities than previously reported, based simply on different definitions of land area, with no impact on capacity factor. Thus, existing wind turbines may extract more wind power over less land or water than previously thought.

COMPARISON OF PLATELET COUNTS SHOWN BY AUTOMATIC HAEMATOLOGY ANALYSERS AND COUNTS MEASURED MANUALLY IN POPULATION OF MOUNTAINOUS HILLY REGION OF CHENAB VALLEY ATTENDING OPD ON ROUTINE BASIS IN GMC DODA. ASSOCIATED HOSPITAL

In clinical practice it is very important to perform the platelet counts. The estimation of platelet counts from peripheral blood smears is an accurate method and provides adequate quality assurance in traditional methods as the automated cell counters are not available at all hospital setups especially in rural areas. In modern era use of automated analyzers based on impedance technology has resulted in improvement of accuracy and helps in measurement of platelet indices such as Mean Platelet Volume (MPV) Plateletcrit (PCT) and Platelet Distribution Width (PDW). However, both the methods have certain limitations. Platelet counts were estimated on a 5-part Differential Automated Hematology Analyzer and manually on Leishman stained peripheral blood SMEAR.
 Aims & Objective: 1. This study was conducted to compare platelet counts by peripheral blood smear method and automated method in patients attending OPD on routine basis in a mountainous hilly region of J&k .
 
 It also aims to study the relation, if any, between the platelet count (automated) and platelet indices like Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) and to assess the possible role of these parameters in certain defined situations.
 
 Materials and methods: A prospective study was conducted in a tertiary care hospital on 200 Ethylene Diamine Tetra Acetic acid (EDTA) anticoagulated blood samples. Samples were evaluated by 5-Part differential automated hematology analyser using impedance counting method and by examination of peripheral blood smear method (PBF).
 Results: In thrombocytopenic patients, the platelet count assessed by automated analyzer revealed an inverse relation with Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) and showed large granular and giant platelets on PBS.
 Conclusion: Automated hematology analyzer is essential for immediate and accurate complete blood count evaluation but blood samples showing erroneous results or low platelet counts on analyzer should be confirmed on peripheral blood smear. The platelet indices like Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) can point to the underlying pathology especially in cases of thrombocytopenia.
 Keywords: Automated analyser, Peripheral blood smear, MPV, PDW, large granular platelets.

How many apples make a quarter? The challenge of discrete proportional formats

Proportional judgments are easier for children in continuous formats rather than discretized ones (e.g., liquid in a beaker vs. in a beaker with unit markings). Continuous formats tap a basic sense of approximation magnitude, whereas discretized formats evoke erroneous counting strategies. On this account, truly discrete formats with separated objects should be even harder. This study (N = 565 7- to 12-year-old children) investigated that prediction. It also examined whether the format effects vary with children’s fraction knowledge (FK; part–whole relations, computation, and fraction number line estimation). As found previously, discretized formats were more challenging than continuous ones; as predicted, discrete formats were yet harder. The format effect interacted with FK. Low-FK children were above chance only with continuous formats, medium-FK children struggled with discrete formats only, and high-FK children did well with all three formats.

Validation of a new method for estimating low platelet counts: G&S method

ABSTRACT Introduction: Automated hematology analyzers are able to produce low platelet counts with great precision and accuracy. However, these analyzers may produce erroneous counts due to the presence of interferences. Therefore, additional methodologies are required to confirm platelet counts, such as blood smear and a direct count, using the Neubauer chamber. Objective: To validate the reliability estimate produced by the G&S method. Material and method: One hundred and fifty platelet counts were analyzed in the hematology and emergency laboratories of the Hospital Nacional Docente Madre-Nino San Bartolome, in Lima, Peru, by four methodologies: one optical platelet count (PLTO), one indirect blood smear count (Indirect), and two direct counts (Direct and G&S). Descriptive and inferential statistics were used to compare the groups. Results: A significant difference was observed in the distribution of the four methodologies and, after applying the post-hoc analysis, a similarity between the PLTO and G&S methods was found. Also, the Direct, G&S and Indirect methods showed a positive correlation with the PLTO method. The Bland-Altman test demonstrated that the G&S method presented a high agreement with the PLTO method. Conclusion: The G&S method is inexpensive, easy to perform, and has demonstrated statistical reliability concerning the automated methodology, and is useful for confirming low platelet counts after a suspected error by the automated equipment or when this device is not available for use.

Children’s learning from others: Conformity to unconventional counting

The current study investigated whether children’s conformity to a majority testimony influenced their willingness to revise their own erroneous counting knowledge. The content of the testimonies focused on conventional rules of counting, by means of pseudoerrors (i.e., unconventional counts) occurring during a detection task. In this work measurements were taken at two different time points. At time 1 children aged 5 to 7 years (N = 88) first made independent judgments on the correctness of unconventional counting procedures presented by means of a computerized detection task. Subsequently, they watched a video in which four teachers (unanimous majority) or three (non-unanimous majority) made correct claims about the counts and children had to decide whether the informants were right or not, and justify their answers. Our participants conformed significantly more when the correct testimony was provided by a unanimous majority than by a non-unanimous majority. In addition, in two of the three pseudoerrors presented, there was no difference in the children’s tendency to conform to unconventional counts as age increased. At time 2, which was taken to test whether the effect of the testimony was maintained over time, the responses of the 32 children (16 from each age group) who had endorsed the claims of the unanimous majority at time 1 revealed that teachers’ testimonies only had a lasting influence on elementary school children’s understanding of conventional counting rules.

PreCount: a predictive model for correcting real-time occupancy count data

Sensing the number of people occupying a building in real-time facilitates a number of pervasive applications within the area of building energy optimization and adaptive control. To ascertain occupant counts, the adoption of camera-based sensors i.e. 3D stereo-vision and thermal cameras have grown significantly. However, camera-based sensors can only produce occupant counts with accumulating errors. Existing methods for correcting such errors can only correct erroneous count data at the end of the day and not in real-time. However, many applications depend on real-time corrected counts. In this paper, we present an algorithm named PreCount for accurately correcting raw counts in real-time. The core idea of PreCount is to learn error estimates from the past. We evaluated the accuracy of the PreCount algorithm using datasets from four buildings. Also, the Normalized Root Mean Squared Error was used to evaluate the performance of PreCount. Our evaluation results show that in real-time PreCount achieved a significantly lower Normalized Root Mean Squared Error compared to raw counts and other correction approach with a maximum error reduction of 68% when benchmarked with ground truth data. By presenting a more accurate algorithm for estimating occupant counts in real-time, we hope to enable buildings to better serve the actual number of people to improve both occupant comfort and energy efficiency.

Corrigendum to Schneider, Scheu & Brose (2012) DOI: 10.1111/j.1461‐0248.2012.01750.x

In the simulations for our paper ‘Body mass constraints on feeding rates determine the consequences of predator loss’ in Ecology Letters, we discovered a technical flaw which led to wrong predictions of interaction strengths. We apologise for this confusion. Here, we provide a corrected set of parameters which produces qualitatively matching results with regard to the major interpretations of the paper. In addition, we correct an erroneous count of springtails in one replicate of the experiment, resulting in higher experimental interaction strength of spiders on springtails. However, after these corrections, all interpretations of the paper remain valid. As a consequence of these mistakes, we commit ourselves to transparent and reproducible computational research by providing raw data and the full simulation code as an open access repository on GitHub (https://github.com/fdschneider/Schneider_et_al_2012_Corrigendum; DOI: 10.5281/zenodo.10878). All equations and allometric exponents given in the paper remain valid. We refined few parameters to reproduce interaction strengths matching the experiment similarly well as in the original publication: The parameters of the Ricker function (eqn 2 in the paper, success rate): Ropt = 200, γ = 1; the normalisation constants of attack rate: a0 = 0.15; and handling time: h0 = 8.0. All parameters are still in the range of previously documented values (references in original paper). The simulations were initialised with densities N1 = 912, N2 = 350, N3 = 4, N4 = 2 and body masses M1 = 0.0104, M2 = 0.157, M3 = 25.69 and M4 = 125.3 [mg], for springtails, predatory mites, spiders and centipedes respectively (although the body masses reported in the paper were rounded to one digit less). In the simulations we did not assume a delayed restocking of mites as it was the case in the experiment. Simulations reflect a period of 1152 h. The statical estimates of feeding rates reported in the paper are correct. The experimental and simulated ISij were positively correlated at the population level (Pearson's correlation coefficient r = 0.91; P < 0.001; Fig. 4b), whereas the positive correlation at the per capita level was only marginally significant (r = 0.49; P = 0.093). We are grateful to Tomas Jonsson who brought the mistake to our attention and to Kevin Cazelles for a thorough review of the code.

Quasi-differential neutron scattering from 238U from 0.5 to 20 MeV

The Rensselaer Polytechnic Institute Linear Accelerator was used to produce a pulsed neutron beam that was incident on a 238U scattering sample 30m from the source. Eight liquid scintillator (EJ-301) proton recoil fast neutron detectors located at several angles surrounding the sample were positioned at a distance 0.5m. Neutrons resulting from elastic scattering, inelastic scattering, and fission reactions were recorded as a function of time-of-flight. Pulse shape analysis including a new gamma misclassification correction was used to reduce erroneous counts from gamma events produced from fission and inelastic scattering reactions. The experimental data were simulated using an improved model of the Rensselaer Polytechnic Institute neutron scattering system that included individual detector efficiencies and neutron flux shape. The experimental data were compared with several evaluated nuclear data libraries using a figure-of-merit. Overall, the JENDL-4.0 evaluation provided the best agreement with the 238U experimental data. Furthermore, the Rensselaer Polytechnic Institute scattering model was used to constrain uncertainties that allowed for improvements to a new 238U evaluation.

A 3-year longitudinal study of children's comprehension of counting: Do they recognize the optional nature of nonessential counting features?

This 3-year longitudinal study examines developmental changes in children's ability to differentiate essential from nonessential counting features. Kindergarteners watched a computer-presented detection task which included three kinds of counts: correct conventional, erroneous and pseudoerrors (with and without statements of cardinal values for the sets). Children had to judge the correctness of those counts and justify their responses. Our data showed that children's explanations provided additional information and thus increased reliability of the assessment. Children were better at detecting erroneous counts than pseudoerrors and at detecting pseudoerrors with cardinal value than pseudoerrors without it. Group analysis showed that children's performance improved with age but analysis of individual differences qualified this result by identifying individual differences in developmental patterns. This study thus provides a more detailed picture of the developmental trajectories of children's comprehension of essential and nonessential counting aspects.

Waldenström macroglobulinemia with cryoglobulinemia revealed by amorphous deposits on blood smear

We report the case of an 86-year-old woman who presented with a 2-month history of anemia (9 g/dL) and weight loss. She had a medical history of arthrosis and hyperuricemia. Blood tests showed a normocytic aregenerative anemia with mean corpuscular hemoglobin concentration (MCHM) of 31.6 %, platelets 217 9 10/L, white blood count 3.3 9 10/L with lymphopenia (0.66 9 10/L) associated with elevated CRP (62 mg/L) and hypoproteinemia (58 g/L). TSH and creatinine were normal. Ultrasound and computed tomography revealed a hepatosplenomegaly, and positron emission tomography showed increased uptake in a right inguinal lymph node, biopsy of which revealed no tumor infiltrate. Examination of the blood smear showed amorphous lightly basophilic deposit mimicking white cells or platelet aggregates. The deposits had the same color and appearance as immunoglobulin inclusion in Mott cells, suggesting cryoglobulinemia. Laboratory tests confirmed the presence of cryoglobulin, characterized as an IgM lambda monoclonal protein (3.5 g/L). Due to the lack of evident etiology of this anemia, a bone marrow aspiration was done; smear examination revealed significant infiltration (83 % of the cells) by lymphoplasmocytoid cells which, with the cryoglobulinemia, permitted the diagnosis of Waldenstrom macroglobulinemia. Revelation of lymphoid hemopathy by cryoglobulin precipitates on blood smear remains rare and atypical [1]. The presence of cryoglobulin frequently results in erroneous WBC or platelet counts with pseudoleukocytosis or pseudothrombocytosis [2], whereas in our case

Rapid enumeration of Oenococcus oeni during malolactic fermentation by flow cytometry

The aim of this study was to provide a method to rapidly enumerate Oenococcus oeni cells during malolactic fermentation (MLF). To keep MLF under control, it is important to monitor the growth of the bacteria O. oeni. However, the enumeration of O. oeni using the plate count technique requires a very long incubation time of about 10 days or more, which is not adapted to monitoring MLF in real time. Flow cytometry (FCM), in combination with several fluorescent probes, is a rapid method for counting large numbers of bacterial cells. However, probes based on fluorescein [FDA, carboxyfluorescein diacetate (cFDA)] did not give good results for O. oeni. For the first time, we propose using the BacLight™ kit for enumeration of O. oeni, and we compare the results with three methods: plate count and FCM, in combination with either fluorescein probes or the BacLight™kit. The last method provides a perfect correlation with the plate count method. FCM coupled with the Baclight™ kit makes it possible to count O. oeni cells during MLF with a perfect correlation with the plate count method. The result is obtained in 20 min vs 10 days with the reference method which will be very useful for wine microbiologists. Moreover, it should be emphasized that FDA/cFDA staining is not recommended because it can lead to an erroneous count during the latency period or at the end of growth due to the variation of intracellular pH in the O. oeni cells during growth.

The Prognostic Value of Lymph Node Cross-Sectional Cancer Area in Node-Positive Breast Cancer: A Comparison with N Stage and Lymph Node Ratio

The number of positive axillary lymph nodes (LNs) is the only node-related factor for prognostic evaluation of breast cancer recognized by AJCC (TNM staging). However, N staging may not completely reflect LN tumor involvement due to the erroneous count of LNs in the presence of matted LNs and different tumor volume in LNs. Additionally, the positive/total LN ratio (LNR) has been shown to outperform N staging in survival prediction. In our study, to better quantify the tumor involvement of axillary LNs, we measured the cross-sectional cancer area (CSCA) of the positive LNs in 292 breast cancer patients diagnosed between 1998 and 2000 in our institution and compared its prognostic value to that of number of positive LNs (metLN)/N stage and LNR. Statistical analyses of these three LN-related factors were performed by Kaplan-Meier method and multivariate Cox's regression model. Patients were divided into three groups based on the different LN CSCA (<50, 50–500, and >500 mm2), or LNR (<0.1, 0.1–0.65, and >0.65), or N stage (N1–N3). Multivariate analysis demonstrated LNR was the most significant LN-related survival predictor with hazard ratio (HR) 25.0 (P = 0.001), compared to the metLN (HR 0.09, P = 0.052) and CSCA (HR 2.24, P = 0.323).

Lymph nodal staging for non-small-cell lung cancer

We read with interest Matsuguma et al.’s recent paper in the journal [1] on the optimum method of lymph node (LN) staging for non-small-cell lung cancer (NSCLC). We congratulate the authors on their elegant analysis of the data to conclude that the LN ratio had the best discriminatory power, followed by the LN number, both of which were superior to the current nodal staging system. Several other authors [2–5] have come up with similar results and have espoused the use of either the LN ratio or positive LN number for the pathological staging of NSCLC. In an ideal world, with uniform standards of surgery, pathology grossing and reporting, there is no doubt that these methods would be superior to the conventional lymph nodal staging system. We, however, believe that there are several points to be considered before recommending that these be used to modify the existing tumour node metastases (TNM) staging system. First, it is often difficult to get an accurate count of the number of LNs harvested in the mediastinum. Frequently, this depends not only on the expertise of the operating surgeon, but also the diligence of the pathologist grossing the specimen. Moreover, anthracotic LNs in the mediastinum often fragment, thereby giving an erroneous count. Secondly, the ratio of metastatic LNs would be widely variant between surgeons, thoracic units and institutions depending on their surgical philosophy, expertise and again, the pathologist. Surgeons performing mediastinal LN sampling would have very different LN ratios from those who perform a radical systematic mediastinal LN dissection. Paradoxical results could appear due to an inordinately high pick-up of normal LNs, reducing the LN ratio. Thirdly, preoperative LN staging, already inaccurate, would become even more inaccurate as it would be virtually impossible to get a metastatic LN ratio or even an LN number based on radiological investigations or even a mediastinoscopy. Finally, these methods would increase the complexity of staging, making them less likely to be complied with by routine pathology reporting. While we agree wholeheartedly with the authors that the LN ratio or number would be superior to the existing TNM staging system, we would be reluctant to advocate the adoption of these methods in the TNM staging system.

Managing atrial fibrillation in the CRT patient: Controversy or consensus?

The cumulative incidence of new onset atrial fibrillation (AF) in patients undergoing cardiac resynchronization therapy (CRT) is substantial, exceeding 25% in multiple recent studies. Although AF patients undergoing CRT show improved echocardiographic parameters, functional status, and quality of life in, they benefit to a lesser degree than do patients in normal sinus rhythm. They also exhibit a trend toward increased mortality. Understanding the barriers to response from CRT among AF patients is critical to addressing the needs of growing populations of patients with AF and HF. Foremost among these are suboptimal biventricular pacing, often characterized by fusion or pseudo-fusion complexes, leading to inefficient CRT delivery. Furthermore, AF increases the risk of inappropriate shocks, which lead to substantial psychiatric morbidity, increased risk of heart failure hospitalization, and may also increase mortality. Assiduous rate control is reasonable for all AF patients receiving CRT, but there is a paucity of data regarding specific antiarrhythmic drug therapy recommendations. For patients with permanent AF and severe symptoms, atrioventricular junction ablation appears effective in improving response by ensuring biventricular capture and reducing implantable cardioverter-defibrillator shock burden in selected patients. Catheter-based techniques such as pulmonary vein isolation appear more attractive and in the future may offer further advantages and lower risks, particularly for patients with paroxysmal AF.

Accuracy of Platelet Counting by Automated Hematologic Analyzers in Acute Leukemia and Disseminated Intravascular Coagulation

Platelet counting in patients with acute leukemia or disseminated intravascular coagulation (DIC) may have a risk for erroneous counts owing to the presence of nonplatelet particles or platelet activation. We evaluated automated platelet counting methods using the Abbott Cell-Dyn Sapphire (Abbott Diagnostics, Santa Clara, CA), Sysmex XE-2100 (Sysmex, Kobe, Japan), ADVIA 2120 (Siemens Diagnostics, Tarrytown, NY), and Beckman Coulter LH 750 (Beckman Coulter, Miami, FL) compared with the international reference method (IRM). Automated platelet counting methods were inaccurate compared with the IRM, without evidence of interfering nonplatelet particles. It is interesting that platelet activation markers were associated with DIC severity and erroneous platelet counting, suggesting that platelet activation is a potential source of inaccuracy. Furthermore, the artifactual in vitro platelet activation induced a high degree of intermethod variation in platelet counts. The inaccuracy of automated platelet counts increased the risk for misdiagnosis of DIC. More attention needs to be given to the accuracy of platelet counts, especially in clinical conditions with florid platelet activation.

How you count counts: the importance of methods research in applied ecology

1 Methods papers play a crucial role in advancing applied ecology. Counting organisms, in particular, has a rich history of methods development with many key advances both in field sampling and the treatment of resulting data. 2 Most counts, however, have associated errors due to portions of the population of interest being unavailable for detection (e.g. target population not fully sampled; individuals present but not detectable), detection mistakes (e.g. detectable individuals missed; non-existent individuals recorded), or erroneous counts (e.g. large groups miscounted; individuals misidentified). 3 Developments in field methods focus on reducing biases in the actual counts. Simultaneously, statisticians have developed many methods for improving inference by quantifying and correcting for biases retrospectively. Prominent examples of methods used to account for detection errors include distance sampling and multiple-observer methods. 4 Simulations, in which population characteristics are set by the investigator, provide an efficient means of testing methods. With good estimates of sampling biases, computer simulations can be used to evaluate how much a given counting problem affects estimates of parameters such as population size and decline, thereby allowing applied ecologists to test the efficacy of sampling designs. Combined with cost estimates for each field method, such models would allow the cost-effectiveness of alternative protocols to be assessed. 5 Synthesis and applications. Major advances are likely to come from research that looks for systematic patterns, across studies, in the effects of different types of bias and assumption violation on the ecological conclusions drawn. Specifically, determining how often, and under what circumstances, errors contribute to poor management and policy would greatly enhance future application of ecological knowledge.

The Development of Proportional Reasoning: Effect of Continuous Versus Discrete Quantities

This study examines the development of children's ability to reason about proportions that involve either discrete entities or continuous amounts. Six-, 8- and 10-year olds were presented with a proportional reasoning task in the context of a game involving probability. Although all age groups failed when proportions involved discrete quantities, even the youngest age group showed some success when proportions involved continuous quantities. These findings indicate that quantity type strongly affects children's ability to make judgments of proportion. Children's greater success in judging proportions involving continuous quantities appears to be related to their use of different strategies in the presence of countable versus noncountable entities. In two discrete conditions, children—particularly 8- and 10-year-olds—adopted an erroneous counting strategy, considering the number of target elements but not the relation between target and nontarget elements, either in terms of number or amount. In contrast, in the continuous condition, when it was not possible to count, children may have relied on an early developing ability to code the relative amounts of target and nontarget regions.

Defining and Defending Murine Models of Plaque Rupture

There is general agreement that atherosclerotic plaque rupture is a major clinical problem and that finding ways to prevent it would be greatly facilitated by an animal model of plaque rupture. The article by Schwartz et al1 seeks to clarify and define the terms used in descriptions of disrupted atherosclerotic plaques, and then to apply these to murine models in order to assess their similarities to and differences from human ruptured lesions. On the face of it this seems a reasonable thing to do, but it has some serious conceptual problems. The first is the issue of whether it is useful at all to provide definitions of disrupted plaques, especially when these are based on histopathology. The second concerns the transferability of such definitions from human to mouse. I would like also to deal with issues relating to reevaluation of existing mouse models of plaque rupture. What do we gain from framing scientific definitions of real-world phenomena? In the context of the ruptured plaque, Schwartz et al1 argue that this would provide an agreed upon and consistent framework that would make it easier for different labs to compare and contrast their data. There is obviously virtue in this as a general principle in science, but we have to consider the possibility that in the developing field of plaque rupture it may be premature. We do not know why plaques rupture, we do not know whether “plaque erosions” are simply the adjacent manifestations of ruptures that are out of the plane of the section, and we do not know whether “plaque fissures” arise through a different set of processes to plaque ruptures. In other words, this means that we do not know whether ruptures, erosions and fissures are ontogenically similar or different. We are therefore moving beyond the boundaries …

Evaluation and correction of subresolved particles by the optical plankton counter in three Australian estuaries with pristine to highly modified catchments

High concentrations of subresolved particles smaller than the 250 μm equivalent spherical diameter (ESD) detection limit of the optical plankton counter (OPC) have hampered its use in turbid estuarine waters. Coincidence of these subresolved particles produced erroneous counts of up to 58 L−1 for 100 μm mesh filtered water samples from three subtropical east Australian estuaries using the laboratory OPC‐1L. The influence of these erroneous counts on in situ OPC‐2T measurements was assessed by comparison with measurements of simultaneously collected net zooplankton using the laboratory OPC‐1L. The total zooplankton abundance from the in situ OPC‐2T measurements could be corrected for erroneous counts of subresolved particles using OPC‐1L measurements of 100 μm mesh filtered water sampled from the same site but with large error. No such corrections were possible for OPC‐2T measurements of total zooplankton biomass or normalized biomass size spectra (NBSS). No meaningful or significant correlations were found between the abundance or biomass of subresolved particles and in situ light attenuance, probably due to tannin‐rich waters with low subresolved particle concentrations. NBSS of simultaneously collected net zooplankton from OPC‐1L measurements indicated higher biomass in the disturbed Manning and Wallamba rivers, whose catchments support intensive livestock agriculture and some residential development, compared to the forested Wallingat River. NBSS may therefore be a useful indicator of nutrient enrichment in estuaries. The slope of NBSS may respond to both production of small particles and the predation and loss of large particles.