Search results for "seasonality"

Phytoplankton primary production in a eutrophic cooling water pond

1984

The seasonal variation of phytoplankton photosynthesis was measured with 14C-method in a warmed ice-free pond in central Finland. Simultaneously with in situ measurements the photosynthesis was also measured in an incubator with different water temperatures and constant light (ca. 16 W m−2). The total annual photosynthesis was 57.2 C m−2 a−1. The portion of the winter and spring production of the annual photosynthesis was 18.4%, that of the autumn production ws 17.4%. Thus 64.3% of the total annual phytoplankton photosynthesis occurred in the three summer months. The range of the daily integrated photosynthesis per unit area was 1.9—563 mg C m−2d−1. The photosynthetic rate per unit chloroph…

A Short-Term Data Based Water Consumption Prediction Approach

2019

A smart water network consists of a large number of devices that measure a wide range of parameters present in distribution networks in an automatic and continuous way. Among these data, you can find the flow, pressure, or totalizer measurements that, when processed with appropriate algorithms, allow for leakage detection at an early stage. These algorithms are mainly based on water demand forecasting. Different approaches for the prediction of water demand are available in the literature. Although they present successful results at different levels, they have two main drawbacks: the inclusion of several seasonalities is quite cumbersome, and the fitting horizons are not very large. With th…

A theoretically-based overland flow resistance law for upland grassland habitats

2022

Abstract Sediments conveyed from interrill areas to rills are transported by a thin flow (overland flow) and the knowledge of overland flow resistance is useful to evaluate overland flow velocity and sediment transport capacity. The aim of this paper was to verify the applicability of a theoretical overland flow resistance law, based on a power-velocity distribution, using field measurements for four upland grassland types used in different management strategies (Hay Meadows, Low-density Grazing, Rushes and Rank Grassland). Particular attention was deserved to the effects of vegetation growth cycles on the surface roughness and the corresponding reduction of overland flow velocity. The rela…

Last interglacial temperature seasonality reconstructed from tropical Atlantic corals

2016

Abstract Reconstructions of last interglacial (LIG, MIS 5e, ∼127–117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. We present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire (Caribbean Netherlands). These have been precisely dated by the 230Th/U-method to between 130 and 120 ka ago. Annual banding of the coral skeleton enabled construction of time windows of monthly resolved strontium/calcium (Sr/Ca) temperature proxy records. In conjunction with a previously published 118 ka coral record, our eight records of up to 37 …

A Critical Comparison of Remote Sensing Leaf Area Index Estimates over Rice-Cultivated Areas: From Sentinel-2 and Landsat-7/8 to MODIS, GEOV1 and EUM…

2018

Leaf area index (LAI) is a key biophysical variable fundamental in natural vegetation and agricultural land monitoring and modelling studies. This paper is aimed at comparing, validating and discussing different LAI satellite products from operational services and customized solution based on innovative Earth Observation (EO) data such as Landsat-7/8 and Sentinel-2A. The comparison was performed to assess overall quality of LAI estimates for rice, as a fundamental input of different scale (regional to local) operational crop monitoring systems such as the ones developed during the "An Earth obseRvation Model based RicE information Service" (ERMES) project. We adopted a multiscale approach f…

Night, day, sunrise, sunset: do fish under snow and ice recognize the difference?

2008

1. Although boreal lakes are ice-covered for several months annually, little is known about the behaviour of fish under ice. To consider the reasons for diel vertical migrations (DVM) it is important to compare periods under ice as opposed to under open water. Echosounding provides a tool for non-intrusive continuous monitoring of fish, even in winter. 2. Changes in the vertical distribution of fish through six 48-h periods were monitored using a stationary, mounted echosounder that beamed vertically either from the bottom up or from the surface down from February to April, 2003. The up-beaming and down-beaming transducers were run alternately for 24 h each over the 48-h period. Standard ec…

Spatial, seasonal and long-term variability of phytoplankton photosynthesis in lakes

1994

Rotifer vertical distribution in a strongly stratified lake: a multivariate analysis

1998

The main source of variation of rotifer species distributions in lake Arcas-2, a small karstic lake near Cuenca (Spain), was explored by means of principal components factor (PCA) and canonical correlation (CCA) analyses. PCA was performed using rotifer densities and CCA using rotifer densities plus physical and chemical parameters. Factor 1 of PCA separated summer species from winter-spring species and Factor 2 accounted for the variation in the vertical profile. Three summer species with different food habits (Polyarthra dolichoptera, Hexarthra mira and Asplanchna girodi) were grouped together at the positive end of Factor 1, while Factor 2 separated the two hypolimnetic species (Filinia …

Development of tree-ring maximum latewood density chronologies for the western Tien Shan Mountains, China: Influence of detrending method and climate…

2013

a b s t r a c t Three tree-ring maximum latewood density chronologies were developed from high elevation Picea schrenkiana sites in the western Tien Shan Mountains using different detrending methods. The new chro- nologies extend back to the early 16th and late 17th centuries, and contain significant late spring and summer temperature signals, respectively. An assessment of varying detrending methods and band-pass filtering the chronologies revealed only slightly differing low frequency trends retained in the maximum latewood densities. The distance between sampling sites and the varying seasonality of limiting climatic factors are identified as key drivers affecting the correlation among t…

Effects of temporal abiotic drivers on the dynamics of an allometric trophic network model

2023

Current ecological research and ecosystem management call for improved understanding of the abiotic drivers of community dynamics, including temperature effects on species interactions and biomass accumulation. Allometric trophic network (ATN) models, which simulate material (carbon) transfer in trophic networks from producers to consumers based on mass-specific metabolic rates, provide an attractive framework to study consumer–resource interactions from organisms to ecosystems. However, the developed ATN models rarely consider temporal changes in some key abiotic drivers that affect, for example, consumer metabolism and producer growth. Here, we evaluate how temporal changes in carrying ca…