Body size is manifestly one of the most important attributes of an organism from an ecological and evolutionary point of view. Size has a predominant influence on an animal's energetic requirements, its potential for resource exploitation, and its susceptibility to natural enemies. A large literature now exists on how physiological, life history, and population parameters scale with body dimensions (24, 131). The ecological literature on species interactions and the structure of animal communities also stresses the importance of body size. Differences in body size are a major means by which species avoid direct overlap in resource use (153), and size-selective predation can be a primary organizing force in some communities (20, 70). Size thus imposes important constraints on the manner in which an organism interacts with its environment and influences the strength, type, and symmetry of interactions with other species (152, 207). Paradoxically, ecologists have virtually ignored the implications of these observations for interactions among species that exhibit size-distributed populations. For instance, it has been often suggested that competing species

https://www.jstor.org/stable/pdf/2096954.pdf

The ontogenetic niche and species interactions in size-structured populations

The Intergovernmental Panel on Climate Change (IPCC) Technical Paper Climate Change and Water draws together and evaluates the information in IPCC Assessment and Special Reports concerning the impacts of climate change on hydrological processes and regimes, and on freshwater resources – their availability, quality, use and management. It takes into account current and projected regional key vulnerabilities, prospects for adaptation, and the relationships between climate change mitigation and water. Its objectives are:

/pdf/climate-change-and-water-2dpc0zbpsj.pdf

Climate change and water.

http://snobear.colorado.edu/Markw//WatershedBio/10/Week15/Carpenter.pdf

Cascading Trophic Interactions and Lake Productivity

Communities of microscopic plant life, or phytoplankton, dominate the Earth's aquatic ecosystems. This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities in lakes and rivers and oceans. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity. Although focussed on one group of organisms, the book develops many concepts relevant to ecology in the broadest sense, and as such will appeal to graduate students and researchers in ecology, limnology and oceanography.

/pdf/the-ecology-of-phytoplankton-4ev70n3jsq.pdf

The Ecology of Phytoplankton

The rise of harmful cyanobacteria blooms: The potential roles of eutrophication and climate change

The maximum size of plastic bead ingested by Bosmina Zongirustris and six species of Daphnia increased with increasing body size of the animals. The relationship between the diameter (,u) of the largest bead ingested ( y ) and carapace length (x, in mm) is given by an expression, y = 22x + 4.87. This relationship could be used to predict which members of a phytoplankton community would be available as food for different-sized -species of filter-feeding Cladocera.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1968.13.4.0675

The relationship between body size of filter‐feeding cladocera and the maximum size of particle ingested

The size-efficiency hypothesis, first proposed in 1965 by Brooks & Dodson (24), has profoundly influenced the direction of research in aquatic ecology since its publication.3 The size-efficiency hypothesis (SEH) is an attempt to explain the commonly observed inverse relationship between the abundances of smalland of large-bodied herbivorous zooplankton in freshwater lakes. The SEH was originally stated as follows:

The Size-Efficiency Hypothesis and the Size Structure of Zooplankton Communities

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1969.14.5.0693

Relation between filtering rate, temperature, and body size in four species of daphnia

Until recently, biological drivers of plankton aggregation were under-appreciated, because most studies concentrated on physical processes. New technological advances, novel experiments and theory have shifted focus to the pivotal role of behaviour in plankton patch dynamics. Our review highlights four biological drivers of zooplankton spatial patchiness and brings together recent research on well studied marine and freshwater taxa, primarily copepods and cladocerans. Diverse and powerful behavioural responses by zooplankton to physical and chemical signals are shown to contribute to the formation and breakdown of zooplankton patches over several different spatial scales.

Biological drivers of zooplankton patchiness.

Traditionally, diatoms have been associated w ~ t h productive pelagic food chains that lead, through suspensionfeeding planktonic copepods, to top consumers and important fisheries Here, 15 laborator~es located ivorldw~de in 12 d~ffer ent countries and representing a variety of marine, estuarine and freshwater environments present strong evidence that diatom diets are in fact inferior for copepod reproduction When fed to females of 16 copepod species, all but 1 of the 17 diatoms e x a m ~ n e d significantly reduced egg production rates or egg viability compared to non-diatom controls These effects are hypothesized to influence copepod recruitment patterns and the flow of energy in marine food webs. KEY WORDSDiatom-copepod mteractions . Copepod recruitm e n t . Food webs The 'classic' pelagic food web refers to the widely held concept of a trophic linkage between outbursts of diatom-rich phytoplankton, copepod production and fish (Runge 1988, Cushing 1989, Legendre 1990). The spring diatom bloom, for example, is considered to initiate and support the cycle of secondary production and growth of fish larvae that depend predominantly on the egg and naupliar stages of planktonic copepods, the dominant constituents of the zooplankton in most oceanic regions, for food (Turner 1984, Mann 1993). The stratified waters of the oligotrophic or post-bloom temperate ocean, on the other hand, support a flagellate-dominated, microbial production, which has traditionally been considered to be ineffectively transferred to the mesozooplankton and fish (Cushing 1989). It has long been known that many copepod species feed on diatoms in the sea (Lebour 1922, Marshal1 & Orr 1955). However, the importance of diatoms as a dominant and high quality food source for copepod product~on has recently been questioned (Kleppel et al. 1991, Kleppel 1993). For example, new studies have reported that some diatom species induce copepod egg mortality by blocking embryogenesis (Poulet et al. 1995, Ianora et al. 1996, Uye 1996). The implications of these results challenge the traditional view of the role of diatoms in the pelagic food web. Here, we report observations designed to determine 'Authors given in a lphabet~c order. \"Addressee for correspondence. E-mail: poulet@sb-roscoff.fr whether the inhibitory effects of diatoms on copepod '\"Present address. Faculty of Apphed Bioloqical Science, are indeed a phenomenon. Hiroshima University, ~ i ~ a s h i ~ i r o s h i m a , .Japan Using the same protocols described in detail in Poulet O Inter-Research 1997 Resale o f full article n o t permjt ted Mar Ecol Prog Ser 157: 287-293, 1997 et al. (1995) and Uye (1996), 15 laboratories located worldwide have examined the reproductive response of a number of copepod species to different diatom species, representing a variety of temperate and subarctic freshwater, estuarine, and coastal ocean environments (see Table 1). The reproductive response of copepods to various food treatments was quantified by incubating adult females in containers holding 150 to 1000 ml, 0.45 pm filtered seatvater enriched with diatom or non-diatom (control, usually a dinoflagellate) diets. Algae were cultured in F/2 (diatoms) and K (non-diatoms) media (Guillard & Ryther 1962, Keller et al. 1967) and were given in excess (10' to 10' cells ml-') to copepods. Experiments ran for 4 to 40 d, depending on the copepod species and diets. Each day, copepods were transferred to new containers with fresh media and eggs were counted and left undisturbed for 48 to 72 h to determine hatching success. Details of preparation of phytoplankton extracts are given elsewhere (Poulet et al. 1994, Uye 1996). Tests demonstrating that culture media, bacteria in cultures and anoxia did not affect hatching had already been conducted (Ianora et al. 1996, Uye 1996). Among the 37 diatom-copepod combinations examined, there were 4 categories of responses (Table 1, Fig. 1). Except for 1 combination (Category IV), where there was no negative effect, diatoms supported either lower copepod fecundity (Category 111) or hatching success (Category 11) or both (Category I) , when compared to non-diatom diets (p i 0.01). Thus, while diatoms may provide a source of energy and materials for copepod growth (Vidal 1980), they often reduce fecundity and/or hatching success. These observations constitute the paradox of diatom-copepod interactions in the pelagic food web. How can diatoms support copepod development yet depress their reproductive potential? The results in Table 1 show that diatoms reduced fecundity, on average, by 87 % (Categories I and 111) and hatching success by 80% (Categories I and 11) with time. Non-diatom diets in controls (Table 2) induced negligible changes in both fecundity (+ 16 %) and hatching success (-4 %). Among cultured clones, the same diatom species showed considerable intraspecific differences in their impact (e.g. Skeletonema costatum, Phaeodactylum tncornutum), reflecting species-specific feeding behaviors or variable intracellular composition of the algae. For example, S. costatum reduced fecundity and hatching in Acartia clausi, fecundity but not hatching in Calanus helgolandicus, and neither of the two in C. finmarchicus. Chaudron et al. (1996) have shown that a decrease in egg viability was significantly correlated to diatom cell concentrations in diets. In the present study, hatching success was affected at even lower diatom concentrations of 102 cells ml-' (Fig. 2). In temperate waters, cell Control l

/pdf/the-paradox-of-diatom-copepod-interactions-501ek2j7rs.pdf

Carolyn W. Burns

Papers

The relationship between body size of filter‐feeding cladocera and the maximum size of particle ingested

The Size-Efficiency Hypothesis and the Size Structure of Zooplankton Communities

Relation between filtering rate, temperature, and body size in four species of daphnia

Biological drivers of zooplankton patchiness.

The paradox of diatom-copepod interactions