The production of ‘food boluses’ by Antarctic krill and implications for organic matter transport

Antarctic krill (Euphausia superba) are a key species in the marine Antarctic ecosystem. Food boluses, a byproduct of feeding where krill form a compact food mass within their feeding basket, were formed and rejected under laboratory conditions. We explored the mechanism used to form these boluses by examining krill feeding behaviour and observed two distinct scenarios that can lead to the formation of boluses: 1) when concentrations of food items are too high for krill to filter feed efficiently; 2) when either biological or foreign particles are caught in the feeding basket and unable to be processed by the krill. We measured the frequency of rejection of the boluses, along with their composition, sinking rates, and carbon and nitrogen contents. For cell concentrations over 108 cells L-1, the frequency of rejection ranged from 2.6 to 17 boluses per hour. Bolus sinking velocities averaged 367 m d-1, with carbon and nitrogen contents averaging 24.1 µg C mm-3 and 2.3 µg N mm-3, respectiv..., , # Data from: The production of ‘food boluses’ by Antarctic krill and implications for organic matter transport

Dataset DOI: [10.5061/dryad.cvdncjtg0](10.5061/dryad.cvdncjtg0)

## Description of the data and file structure

This dataset was collected to investigate how Antarctic krill (*Euphausia superba*) form and reject food boluses under varying phytoplankton concentrations, and to quantify the physical and elemental characteristics of these boluses. Experiments were conducted in temperature-controlled laboratory conditions using captive krill fed different microalgal diets. Measurements include the size, sinking velocity, carbon and nitrogen content, and production/rejection rates at different food concentrations of both boluses and faecal pellets.

### Files and variables

#### File: Bolus_krill_data.xlsx

**Tab 1_Bolus**

**Description:** Measurements of individual food boluses formed by Antarctic krill under laboratory conditions.

##### Variables

* Diet- Genus of microalgae fed...,

南极磷虾（Antarctic krill, Euphausia superba）是南极海洋生态系统中的关键物种。食物团（food boluses）是磷虾摄食过程中的副产物，指磷虾在其摄食篮内形成的致密食物团，此类食团可在实验室条件下形成并被排出。本研究通过观测磷虾摄食行为，探究了此类食团的形成机制，共发现两类可诱导食团形成的情形：1）食物颗粒浓度过高，导致磷虾无法高效滤食；2）生物颗粒或外来颗粒物被摄食篮捕获，且无法被磷虾处理。本研究测定了食团的排出频率、组成、沉降速率以及碳、氮元素含量。当细胞浓度超过10^8 个·L^-1时，食团排出频率为每小时2.6至17个。食团沉降速率平均为367 m·d^-1，碳、氮元素含量分别平均为24.1 μg C mm^-3与2.3 μg N mm^-3，……
# 数据来源：《南极磷虾的“食物团”生产及其对有机质输运的启示》

数据集DOI：[10.5061/dryad.cvdncjtg0]

## 数据与文件结构说明
本数据集旨在探究南极磷虾（Antarctic krill, Euphausia superba）在不同浮游植物浓度下形成并排出食物团的机制，并定量测定此类食团的物理与元素特征。实验在控温实验室条件下开展，使用饲喂不同微藻饵料的圈养磷虾进行。测定指标包括食团与粪便颗粒的尺寸、沉降速率、碳氮含量，以及不同食物浓度下的食团产生/排出速率。

### 文件与变量
#### 文件：Bolus_krill_data.xlsx
**工作表1_Bolus**
**说明：** 实验室条件下南极磷虾形成的单份食物团的测定数据。
##### 变量
* Diet- 饲喂所用微藻的属级类群……