Feeding ecology of benthic filter-feeders at Potter Cove,an Antarctic coastal ecosystem

A rich benthic filter-feeding community is present at Potter Cove, South Shetland, in spite of some usually unfavorable conditions affecting their feeding ecology, such as low phytoplankton production in summer and high sedimentation rates. However, organic material that could fuel the benthic system, such as macroalgal fragments, was detected in the water-bottom interface year-round. Mean assimilation efficiency of several sizes of macroalgal particles under different inorganic particulate percentages varied between 26–51% in a clam, and 26–72% in two ascidian species. Estimated particle flux (feces) produced by ascidians varied according to species and abundance. The C:N ratio of feces was relatively high. Plasticity and profit from the available food sources contribute to the success of the filter-feeding community in Potter Cove.     

Biomass and associations of benthic marine macroalgae from the inner Potter Cove (King George Island, Antarctica) related to depth and substrate

The biomass of the benthic marine macroalgae from the inner Potter Cove was studied along a depth profile across different substrates during Antarctic summer. Macroalgal associations were identified by means of cluster analysis. Twenty-two species were found in the study site, approximately half of the species present in the area. This paucity may be explained by the strong preponderance of the brown algae Desmarestia anceps and D. menziesii, which are able to exclude other species by competition for light. The mean biomass of all macroalgae was 1,390 g DW/m²ǃ,787 g DW/m². Nine macroalgal associations were identified with different preferences for depth, substrate and the degree of exposure. Overall, there was a tendency for macroalgae to grow on fine substrates with increasing depth. Species richness decreased at 20 m depth, probably due to limiting light conditions. The results are discussed with respect to previous studies in East and West Antarctica.     

Food availability and gut contents in the ascidian Cnemidocarpa verrucosa at Potter Cove, Antarctica

A high seasonality characterizes Antarctic environments, and generates marked differences in availability and composition of food for benthic filter feeders. During a year-round period at Potter Cove, Antarctica, algal pigment concentration (chlorophyll a) and organic matter were measured in water column and sediment samples. Chemical composition of gut contents of the ascidian Cnemidocarpa verrucosa was also analyzed. Despite the low standing stock, capture and absorption of organic matter were detected year-round, suggesting intake of other particles besides microalgae. The mechanism that provides food to the ascidians and epibenthic communities may be related to the supply of allochtonous particles, bottom resuspension events, and microbial community dynamics. Sea-ice cycles may affect food availability in terms of water-column mixing and benthic resuspension. The scarce primary production and the high amount of sedimented material are not limiting conditions in Potter Cove, which presents a rich ascidian community.     

Early life history timings in marbled rockcod (Notothenia rossii) fingerlings from the South Shetland Islands as revealed by otolith microincrement

Although it has been reported that Notothenia rossii elsewhere hatches in spring, our daily increment back-counting from the capture date in otoliths of fingerlings caught in Potter Cove, South Shetland Islands, in the 2000s, showed two main periods of larval hatching, one in summer (February–March) and another in winter (July). In concordance, the simultaneous presence of two cohorts born the same year was identified in the age/length frequency distribution of fish sampled in spring 2010, which belonged to biological ages 0+ and 1+ and hatched, respectively, in summer and winter–spring. Maximum and minimum ages of pelagic blue-phase and demersal brown-phase fingerlings were, respectively, 227 and 240 days, indicating a demersal settlement after about 8 months from hatching. The estimated growth rate was 0.23–0.33 mm/day, equivalent to that of South Georgia fingerlings and higher than those of other nototheniids of similar size range. Based on early life events associated with the hatching periods, two types of life cycles are hypothesised for South Shetland fingerlings. The pelagic blue-phase fingerlings (6.5–7.6 cm TL, age group 0+) hatched in July (winter cohort), entering in Potter Cove in February–March. The brown-phase fingerlings (6.3–10.6 cm, mostly of age group 0+) hatched in February–March (summer cohort) and were collected in the cove in spring (the smaller specimens) or in summer (the larger ones). Finally, early juveniles (10.7–15.5 cm, age group 1+) hatched in winter, mainly in July (winter cohort), entering in the cove the following year to spend the second winter inshore.     

Evidence of Macroalgal Colonization on Newly Ice-Free Areas following Glacial Retreat in Potter Cove (South Shetland Islands), Antarctica

Climate warming has been related to glacial retreat along the Western Antarctic Peninsula. Over the last years, a visible melting of Fourcade Glacier (Potter Cove, South Shetland Islands) has exposed newly ice-free hard bottom areas available for benthic colonization. However, ice melting produces a reduction of light penetration due to an increase of sediment input and higher ice impact. Seventeen years ago, the coastal sites close to the glacier cliffs were devoid of macroalgae. Are the newly ice-free areas suitable for macroalgal colonization? To tackle this question, underwater video transects were performed at six newly ice-free areas with different degree of glacial influence. Macroalgae were found in all sites, even in close proximity to the retreating glacier. We can show that: 1. The complexity of the macroalgal community is positively correlated to the elapsed time from the ice retreat, 2. Algae development depends on the optical conditions and the sediment input in the water column; some species are limited by light availability, 3. Macroalgal colonization is negatively affected by the ice disturbance, 4. The colonization is determined by the size and type of substrate and by the slope of the bottom. As macroalgae are probably one of the main energy sources for the benthos, an expansion of the macroalgal distribution can be expected to affect the matter and energy fluxes in Potter Cove ecosystem.     

The benthic macro-algae of Georgian Bay,the North Channel and their drainage basin

Thirty-nine subgeneric taxa of macroalgae have been collected from 83 sites in Georgian Bay, the North Channel and their drainage basin. There were 15 species in the Bay and Channel and 32 species in streams, rivers and impoundments in the basin. Only 8 of the Bay and Channel species were also found in the watershed. Cladophora glomerata was the most important species in Georgian Bay and the North Channel, having an estimated 640 × 10³ m² cover and 19 × 10⁴ kg fresh weight standing crop. However, this species was largely concentrated on the southwestern shorelines of these water bodies. Its distribution along the northeastern shoreline appears to be limited by total ion and phosphorus levels. Chara globularis/vulgaris was the subdominant taxon in Georgian Bay and the North Channel with an estimated 70 × 10³ m² cover and 15 × 10³ kg fresh weight biomass. This species was more widely distributed than C. glomerata. No other taxon contributed significantly to the standing crop including the frequently occurring Ulothrix zonata, Zygnema spp. and Spirogyra spp. The maximum benthic macroalgal biomass was estimated to be approximately 10% of the phytoplankton biomass.     

Ecosystem functioning impacts of the invasive seaweed Sargassum muticum (Fucales,Phaeophyceae)

Ongoing changes in natural diversity due to anthropogenic activities can alter ecosystem functioning. Particular attention has been given to research on biodiversity loss and how those changes can affect the functioning of ecosystems, and, by extension, human welfare. Few studies, however, have addressed how increased diversity due to establishment of nonindigenous species (NIS) may affect ecosystem function in the recipient communities. Marine algae have a highly important role in sustaining nearshore marine ecosystems and are considered a significant component of marine bioinvasions. Here, we examined the patterns of respiration and light‐use efficiency across macroalgal assemblages with different levels of species richness and evenness. Additionally, we compared our results between native and invaded macroalgal assemblages, using the invasive brown macroalga Sargassum muticum (Yendo) Fensholt as a model species. Results showed that the presence of the invader increased the rates of respiration and production, most likely as a result of the high biomass of the invader. This effect disappeared when S. muticum lost most of its biomass after senescence. Moreover, predictability–diversity relationships of macroalgal assemblages varied between native and invaded assemblages. Hence, the introduction of high‐impact invasive species may trigger major changes in ecosystem functioning. The impact of S. muticum may be related to its greater biomass in the invaded assemblages, although species interactions and seasonality influenced the magnitude of the impact.     

BIOMASS,PRODUCTION, AND LITTERFALL IN THE COASTAL SAGE SCRUB OF SOUTHERN CALIFORNIA

A 22-year-old stand of coastal sage scrub in the coastal mountains of southern California had a peak standing aboveground biomass of 1,417 g/m², determined by dimension analysis. Annual aboveground net primary production was 255 g/m²/yr, determined by monthly twig harvests of dominant species and the clipping production of subordinate species. The stand was codominated by two drought-deciduous species, Salvia leucophylla and Artemisia californica, which together comprised 81% of the biomass. Annual litterfall was measured at 194 g/m²/yr. These biomass, production, and litterfall values are less than those measured in most evergreen chaparral communities in California. Seasonally, the two dominant shrubs began aboveground production in the winter soon after the first rains and continued growth for six months until early summer. A massive leaf fall occurred in May–June as the summer drought began, but twig and inflorescence production for both species continued at a high rate into the summer months. Salvia leucophylla had two shoot types: 1) an early spring canopy shoot that elongated rapidly, produced the inflorescence, and died in mid-summer; and 2) a short side shoot produced in late spring with small dense leaves that were retained during the summer drought and early winter. Artemisia californica produced a single cohort of twigs in the early spring, most of which carried inflorescences by late summer.     

Concentration and dispersal of a Pseudo-nitzschia bloom in Penn Cove, Washington, USA

A bloom of the pennate diatom Pseudo-nitzschia, several species of which are associated with the production of the potent excitotoxin domoic acid, was observed in a Puget Sound, Washington embayment in July and August of 1997. Penn Cove, which receives nutrients from the nearby Skagit River and abundant sunshine during summer months due to its location in the rain shadow of the Olympic Mountains, is the home of a commercial mussel farm which supplies shellfish to many coastal areas of the USA. Levels of domoic acid in mussels increased to 3 ppm on 6 and 10 July, corresponding to the observation of a brown algal bloom in Penn Cove. Four species of Pseudo-nitzschia (P. pungens, P. multiseries, P. australis, and P. pseudodelicatissima) were present in our samples from the cove, corresponding to levels of domoic acid in seawater ranging from 0.1-0.8 mirog l(-1) as measured by a receptor binding assay. The highest Pseudo-nitzschia concentration during the time of our sampling was 13 million cells per liter on 28 July. The bloom of Pseudo-nitzschia occurred after a period of strong discharge from the Skagit River and rain accompanied by elevated south and southeasterly winds. Stratification of the cove, providing optimal bloom conditions, was facilitated by weak winds, sunshine, and a freshwater lens at the mouth of the cove. The position of the Pseudo-nitzschia bloom was influenced by buoyancy fronts caused by exchange of water within the cove with that of Saratoga Passage. The decay of this bloom in Penn Cove was accompanied by decreasing nitrate levels at all measured depths. These and future observations aid in the development of a model for prediction of toxic bloom events in the shallow embayments of Puget Sound.     

Seasonal aspects of the biology and diet of nearshore nototheniid fish at Potter Cove,South Shetland Islands,Antarctica

Summary Approximately 1000 specimens belonging to eight fish species were collected at Potter Cove, King George Island, South Shetland Islands, from August 1985 to May 1986. This study deals with the dominant species Notothenia neglecta, Notothenia gibberifrons, Trematomus newnesi and Notothenia rossii marmorata. Age and size structure of the fish were analyzed using scale and otolith readings. Notothenia neglecta was the most abundant species. It spawns in the austral autumn. Juvenile N. rossii marmorata migrate offshore when sexually mature. Over eight hundred stomach contents were analyzed. The four species studied were generally benthophagous. However, in summer T. newnesi and N. rossii marmorata, carried out vertical migrations, feeding on pelagic organisms. Gammarid amphipods constituted the main food in all four species. Algae were consumed regularly throughout the year and we suggest that they are intentially eaten by the fish, rather than by accident. Two 48 hour sampling periods, carried out in summer of 1987, showed that N. neglecta was more active during the day.     

The life history and production of Chaoborus punctipennis (Diptera: Chaoboridae) in Lake Norman,North Carolina,U.S.A.

A study of the life history and production of Chaoborus punctipennis (Say) in Lake Norman, North Carolina, U.S.A. was conducted from February 1978 through January 1979. Four sublittoral (～8 m) and two profundal (～30 m) locations were sampled. Larvae and pupae were collected with a modified Petersen grab and a plankton net, and adults were collected with emergence and light traps. Based on larval, pupal, and adult collections, there appear to be two generations per year — an overwintering spring generation and a summer generation. Annual dry weight standing stock biomass, dry weight production, and P/ B ratio were estimated from each sampling location and depth zone. Production was estimated by the size-frequency method. Standing stock biomass (30.9 mg · m^-2) and production (170.8 mg · m^-2) were highest in the profundal zone. In the sublittoral zone, standing stock biomass and production were 4.7 mg · m^-2, and 29.6 mg · m^-2, respectively. Annual P/ B ratios in the profundal and sublittoral zones were 5.5 and 6.3, respectively.     

Distribution and production of macrophytes and phytoplankton in the lagoon of Venice: comparison of actual and past situation

This paper aims at comparing inedited maps of macrophytes and phytoplankton distribution in the lagoon of Venice in 1980 and 2003. The macrophyte distribution is displayed with reference to different biomass intervals which allow the calculation of the occupied surface, standing crop (SC), net (NPP) and gross (GPP) production. In 1980 the total macroalgal SC was ca. 841 ktonnes whereas the annual NPP and GPP were estimated to be ca. 2912 and 18498 ktonnes, respectively. In 2003 macroalgae displayed a marked regression and the SC, NPP and GPP decreased to ca. 89, 471 and 2336 ktonnes. Maps of the seagrass distribution date back to 1990 but their biomass and production have been quantified only in 2003. On the whole, in 2003, on a surface of ca. 56 km2 the three species living in the lagoon accounted for a SC and a NPP of ca. 209 and 821 ktonnes, whereas the GPP estimated according to literature was about twice as high as the NPP. Cymodocea nodosa was the most abundant phanerogam in the lagoon. Its SC was higher than the total of the macroalgae, although the latter were more productive. Zostera marina covered the highest surface in the lagoon but its biomass and production were a little lower than that of C. nodosa. Nanozostera noltii, which was common and widespread in the past, displayed an evident regression trend which was mainly due to the increase of the water turbidity and the disruptions of its habitat. Similarly, phytoplankton, underwent a descending trend, although data quoted in the present paper display its distribution only in the summer period.     

Photosynthetic light requirements and vertical distribution of macroalgae in newly ice-free areas in Potter Cove,South Shetland Islands,Antarctica

In Potter Cove, Antarctica, newly ice-free areas appeared due to glacial retreat. Simultaneously, the inflow of sediment increased, reducing underwater photosynthetically active radiation (PAR, 400–700 nm). The aim of this study was to determine the photosynthetic characteristics of two macroalgal species colonizing three newly ice-free areas, A1, A2 and A3, with increasing degree of glacial influence from A1 to A3. Turbidity, salinity and temperature were measured, and light attenuation coefficients (K _d) calculated and considered as a proxy for glacial sediment input. The lower depth distribution of the red alga Palmaria decipiens and the brown alga Himantothallus grandifolius was 10 m in A3, 20 m in A2 and 30 m in A1. Both species were then collected, at 5 and 10 m at all areas. Photosynthetic parameters and the daily metabolic carbon balance (CB) were determined. K _d was significantly higher in A3 compared with A1 and A2. The CB of P. decipiens was significantly higher in A1 followed by A2 and A3, and significantly higher at shallower than at greater depth. For H. grandifolius CB was significantly lower in A3 and in A2 at deeper depths compared with the rest of areas and depths. The lower distribution limit of the algae was positively correlated to the light penetration. An increase in the sediment run-off due to global warming might lead to an elevation of the lower depth distribution limit but retreating glaciers can open new space for macroalgal colonization. These changes will probably affect macroalgal primary productivity in Potter Cove with consequences for the coastal ecosystem.     

The summer zooplankton community at South Georgia: biomass,vertical migration and grazing

Zooplankton abundance and biomass were determined during January 1990 at two stations to the north-west of South Georgia using a Longhurst Hardy Plankton Recorder (LHPR). At both shelf and oceanic station sites, zooplankton biomass, (excluding Euphausia superba), was found to be ca. 13 g dry mass m^–2. Copepods and small euphausiids dominated the catches. These estimates are over 4 times higher than values generally reported for the Southern Ocean and may reflect firstly, the high productivity of the study area, secondly, the time of year, summer, when biomass for many species is maximal, and thirdly, the high sampling efficiency of the LHPR. Principal components analysis disclosed similarities and differences between adjacent depth strata in terms of abundance, biomass and species composition. At both stations most variability occurred in the mixed layer (0–60 m) and thermocline (60–120 m) with depth horizons below this being more homogeneous. Diel migrations were observed for most taxa with abundance increasing in the mixed layer at night. At the oceanic station, species and higher taxa belonging to the mesopelagic community were generally well spread throughout this domain and, with the exception of Pleuromamma robusta and Metridia curticauda, showed little evidence of migration. The grazing impact of the epipelagic community (copepods and small euphausiids) was estimated to remove 3–4% of the microbial standing stock day^–1 and a conservative 25% and 56% of daily primary production at the oceanic and shelf stations respectively.     

The impact of zooplankton status on the management of Lake Kinneret (Israel)

Monthly averages of standing stock wet biomass of zooplankton in Lake Kinneret (Israel) varied between 11 and 76 g m^–2 during 1969–1981, with the exception of two months. Averaged contributions of different groups were: Cladocera 58%, Copepoda 35% and Rotifera 7%. Total standing crop wet biomass is highest during January–June, averages varied between 35 and 50 g m^–2, and decreases during summer–fall (23–36 g m^–2). The winter biomass of Cladocera fluctuated between 22 and 35 g m^–2 and dropped to a range of 9–23 g m^–2 in summer, whereas copepod biomass varied very little around an average of 18 g (ww) m^–2 with the exception of low values from April to June. The stock biomass of Rotifera is relatively high during winter floods season (December-March) whilst in summer it is very low.Young stages of fish in Lake Kinneret feed mostly on zooplankton and zoobenthic forms. The most abundant fish in the Kinneret ecosystem, Mirogrex terraesanctae terraesanctae, also feed on zooplankton at the adult stage throughout the year, and herbivorous fish consume zooplankton during the summer when lake plankton resources are limited.The summer ecosystem of Lake Kinneret is characterised as a steady state type, in which the impact of the zooplankton-chain is of great importance. Increase of predation pressure on zooplankton by fish can disequilibrate the balanced trophic relations existing between nannoplankton production and zooplankton grazing capacity. Such a situation can lead to organics accumulation as nannoplankton blooms, resulting in water quality deterioration. Management options aimed at preventing collapse of zooplankton populations are discussed.     

Summer feeding activities of zooplankton in Prydz Bay, Antarctica

Grazing of dominant zooplankton copepods (Calanoides acutus, and Metridia gerlachei), salps (Salpa thompsoni) and microzooplankton was determined during the austral summer of 1998/1999 at the seasonal ice zone of the Prydz Bay region. The objective was to measure the ingestion rates of zooplankton at the seasonal ice zone, so as to evaluate the importance of different groups of zooplankton in their grazing impact on phytoplankton standing stock and primary production. Grazing by copepods was low, and accounted for <1% of phytoplankton standing stocks and 3.8-12.5% of primary production for both species during this study; even the ingestion rates of individuals were at a high level compared with previous reports. S. thompsoni exhibited a relatively high grazing impact on primary production (72%) in the north of our investigation area. The highest grazing impact on phytoplankton was exerted by microzooplankton during this investigation, and accounted for 10-65% of the standing stock of phytoplankton and 34-100% of potential daily primary production. We concluded that microzooplankton was the dominant phytoplankton consumer in this study area. Salps also played an important role in control of phytoplankton where swarming occurred. The grazing of copepods had a relatively small effect on phytoplankton biomass development.     

Year-Round Aggregation of Sandbar Shark,Carcharhinus plumbeus (Nardo, 1827), in Boncuk Cove in the southern Aegean Sea,Turkey (Carcharhiniformes: Carcharhinidae)

The present study provided a two-years assessment to understand the seasonal fluctuations of aggregation of the Sandbar Shark, Carcharhinus plumbeus, in Boncuk Cove in the southern Aegean Sea. Underwater Visual Censuses (UVC) revealed that the species is present in the cove throughout the year but form aggregations only between March and November. Aggregation in groups was observed at a daily sea temperature above 18.1°C and this indicated a possible lower threshold for aggregations for Boncuk Cove population.     

Population studies of three aquatic gastropods in an intermittent backwater

Summary Three snail populations of an intermittent backwater were studied over a 20-month period, and estimates were made of rate of population change, mean biomass, annual and summer net production, and survival under conditions of little standing water. Lymnaea palustris and Physa integra populations were essentially univoltine, while G. parvus appeared to produce several generations during the year. L. palustris formed a protective epiphragm and was apparently better suited to recurrent dry periods than either G. parvus or P. integra, the latter population being maintained through immigration from the stream population. The population density of G. parvus was usually well below, and more aggregated, than the other two species, and there was considerable sampling error associated with its estimated population parameters.The estimated annual production rates for L. palustris and P. integra were 2.18 g/m² and 1.59 g/m², respectively, and these two species accounted for about 98% of the total gastropod production. About 75.9% and 66.5% of the L. palustris and P. integra production, respectively, occurred between June and November. Summer turnover ratios (ratio of production to mean standing crop) in 1969 were 4.69 for L. palustris and 2.94 for P. integra. An extended dry period early in the summer of 1970 reduced total snail production to about 18–24% that of the previous season, although summer turnover ratios were fairly consistent.     

Macrophyte communities and their impact on benthic fluxes of oxygen, sulphide and nutrients in shallow eutrophic environments

The impact of macrophyte communities on benthic fluxes has been analyzed in three shallow coastal environments: Etang du Prévost (Mediterranean coast of France), characterized by the large floating macro-alga Ulva rigida; Certes fishponds (Bassin d'Arcachon), covered by Ruppia cirrhosa; and the inner intertidal mud-flat in the Arcachon Bay (French Atlantic coast), which has extensive Zostera noltii meadows. In these bodies of water, primary production is dependent primarily on the dominant seagrasses and macroalgae that are also responsible for the large quantity of organic matter deposited on the sediment surface. In 1993 and 1994, fluxes of oxygen, sulphide and nutrients were measured in early and late summer, which were selected in order to represent the production and decomposition phases of the dominant macrophytes. Experimental work was undertaken to measure: (1) standing crop of dominant macroalgae and rooted phanerogams and the elemental and macromolecular composition of plant biomass; (2) benthic fluxes of oxygen, sulphide, nitrogen and phosphorus using incubation of multiple dark and light benthic chambers; (3) water-sediment profiles of free-sulphide in sediment cores with rooted phanerogams (Ruppia) as well as with floating Seaweeds (Ulva).At the selected sampling sites, in addition to external (tides) and/or internal (sediment reactivity) factors, we observed differences in benthic fluxes which were clearly related to growth patterns and structure of the macrophyte communities. The Z. noltii meadows were stable and characterized by slow growth and almost constant biomass. In the more sheltered sampling station in the Certes fishponds, R. cirrhosa beds showed a summer decrease due to extensive epiphyte growth. During the decomposition phase, significant fluxes of free-sulphide occurred inside the dark benthic chambers, probably due to the metabolism of the epiphytic layer. In the Etang du Prévost, U. rigida achieved high biomass levels, even though the macroalgal beds exhibited a patchy distribution due to wind action and the hydrodynamics of the lagoon. In the decomposition phase, which was coincident with the annual dystrophic crisis the rapid decomposition of Ulva led to high fluxes of free sulphide.The shift from the production to decomposition phase resulted in substantial changes in nutrient recycling only in the macro-algal-dominated system. During the growth period dissolved inorganic nitrogen and phosphorus were kept at low levels due to macrophyte uptake. In contrast during the decomposition phase when the macroalgal biomass was mineralised, nitrogen and phosphorus were rapidly recycled. The same processes did not occur in the Certes fishponds probably because of the greater internal buffering capacity linked either to plant morphology/physiology or to the properties of the sediment.     

A general biodiversity–function relationship is mediated by trophic level

Species diversity affects the functioning of ecosystems, including the efficiency by which communities capture limited resources, produce biomass, recycle and retain biologically essential nutrients. These ecological functions ultimately support the ecosystem services upon which humanity depends. Despite hundreds of experimental tests of the effect of biodiversity on ecosystem function (BEF), it remains unclear whether diversity effects are sufficiently general that we can use a single relationship to quantitatively predict how changes in species richness alter an ecosystem function across trophic levels, ecosystems and ecological conditions. Our objective here is to determine whether a general relationship exists between biodiversity and standing biomass. We used hierarchical mixed effects models, based on a power function between species richness and biomass production (Y = a × S^b), and a database of 374 published experiments to estimate the BEF relationship (the change in biomass with the addition of species), and its associated uncertainty, in the context of environmental factors. We found that the mean relationship (b = 0.26, 95% CI: 0.16, 0.37) characterized the vast majority of observations, was robust to differences in experimental design, and was independent of the range of species richness levels considered. However, the richness–biomass relationship varied by trophic level and among ecosystems; in aquatic systems b was nearly twice as large for consumers (herbivores and detritivores) compared to primary producers; in terrestrial ecosystems, b for detritivores was negative but depended on few studies. We estimated changes in biomass expected for a range of changes in species richness, highlighting that species loss has greater implications than species gains, skewing a distribution of biomass change relative to observed species richness change. When biomass provides a good proxy for processes that underpin ecosystem services, this relationship could be used as a step in modeling the production of ecosystem services and their dependence on biodiversity.